Sunday, October 31, 2004
Saturday, October 30, 2004
String of beads in radiology-
- Fibromuscular dysplasia
- Chr. Pancreatitis (chain of lakes)
- Small bowel obstruction
- varicose bronchiectasis
condition of unknown aetiology that involves the extracranial internal carotid arteries and vertebral arteries. The internal carotid is involved in about 75% of cases and the vertebral in less than 25%. It is characterized by narrowing of the affected vessel with a string of beads appearance , due to focal annular repetitive intimal and medial proliferative changes. Not infrequently an incidental finding, fibromuscular hyperplasia may be a cause of dissection and is associated with an increased incidence of intracranial aneurysms.
The radiographic changes of hydrostatic oedema are quite characteristic. In the normal adult, the lower lobe pulmonary vessels are larger than the upper lobe vessels due to gravitational forces. As the left-sided pressure increases, the blood is diverted to the upper lobes. This results in "cephalization" with the upper lobe vessels becoming larger than the lower lobe vessels. As left heart pressure increases, fluid enters the peribronchovascular interstitium. As the interstitium becomes oedematous, the interlobular septa become prominent and the markings indistinct. Pleural effusions are frequent in the more severe stages of left heart failure with a slight predominance to the right.
Friday, October 29, 2004
Thursday, October 28, 2004
Wednesday, October 27, 2004
Tuesday, October 26, 2004
a condition in which there is aplasia or obliteration of some or all of the extrahepatic biliary tree: the gallbladder may or may not be involved. It presents in the neonate or young infant with clinical findings of obstructive jaundice and conjugated hyperbilirubinaemia. If undiagnosed or unrelieved progressive biliary cirrhosis will develop. The prognosis is inversely related to the age at which surgery is undertaken and the degree of liver damage. The aetiology is unknown but some consider it to be due to an inflammatory process which leads to progressive obliteration of the bile ducts in the perinatal period.
At ultrasound examination, which should be done following a 4-hour fast, before the onset of cirrhosis, the liver is normal. There is no intrahepatic bile duct dilatation. The gallbladder is not usually seen but if identified it may be spherical. The extrahepatic biliary tree is not seen. A normal ultrasound examination does not exclude the diagnosis. Hepatobiliary scintigraphy using a Tc99m-labelled iminodiacetic acid product (e.g. HIDA) typically demonstrates good hepatic uptake of tracer, with progressive accumulation within the liver but no evidence of excretion into the extrahepatic bile ducts or into bowel. Premedication with phenobarbitone for 5 days prior to the study is recommended to ensure maximal hepatic enzyme function should there be some impairment of liver function. The absence of bowel activity at 24 hours is generally taken to be an indication for liver biopsy and/or operative cholangiography. Findings in neonatal hepatitis include poor hepatocellular uptake of tracer, delayed excretion into bowel and occasionally non-excretion as in biliary atresia.
Treatment is surgical and involves anastomosing an intrahepatic bile duct (usually in segment III) to a loop of jejunum to bypass the extrahepatic obstruction (Kasai procedure). Complications include sepsis and anastamotic stricture. The procedure should be performed as early as possible after diagnosis to avoid complications related to cirrhosis and portal hypertension.
Monday, October 25, 2004
2-4-2005 to 3-4-2005
22nd Karnataka state level conference of I.R.I.A By-D.K chapter of Karnataka state Branch of IRIA At-Dr.T.M.A Pai Convention centre Mangalore Contact :Dr.Raghavendra Bhat. K Address : Balmatta scan Centre.Balmatta Mangalore PH: 0824-2443720,9845071520 Email : firstname.lastname@example.org
8-4-2005 to 10-4-2005
Clinical Course and Hands - on training for Proton MRS of Brain. By-MRI centre, Dr. Balabhai Nanavati Hospital, Mumbai in collaboration with GE healthcare, India At-Dr. Balabhai Nanavati Hospital, S.V. Road, Vile Parle (w), Mumbai - 56 Contact :Dr. Sona Pungavkar,Mobile No. 098202855565Address : Dr. Balabhai Nanavati Hospital, S.V. Road, Vile Parle (w), Mumbai - 56 Ph : 098202855565
Email : email@example.com Website www.nanavatihospital.org
9-4-2005 to 10-4-2005
North Zone Radiology Meet 2005 By-IRIA, Punjab & Chd branch At-Govt. Medical College, Patiala Organiser : Dr. Manoj Mathur Contact : firstname.lastname@example.org Address : 2014 Lal Bagh Street,Patiala Ph : 0175-2212246, 094173-29926 Email : email@example.com
30-4-2005 to 1-5-2005
3rd Chest Radiology Review Course By-REF,IndiaAt-MLT, KEM Hospital, Mumbai Address : Bhaveshwar Vihar, 383 Sardar V. P. Rd Ph: 022-2388-4015 Fax: 022-2382-9595 Email : firstname.lastname@example.org Website www.refindia.net
23-10-2005 to 25-10-2005
ISVIR - 8th Annual Conference At-Pune
Contact : Wg Cdr Hirdesh Sahni Address : Associate Professor , Dept of Radiodiagnosis, AFMC, Solapur Rd, Pune 411040 Ph: 020-26306061, 09370144728 Email : email@example.com Website www.isvir.org
Sunday, October 24, 2004
Clinical:The normal area of the mitral valve is 4 to 6 cm2. Severe stenosis is associated with areas less than 0.8 cm2, and most valves are replaced when their area becomes less than 1.1 cm2. Mitral stenosis results in increased resistance to emptying of the left atrium. This produces a reduced left ventricular output and an increase in pulmonary venous pressure (a valveless system, thus LA pressures are transmitted directly to the vessels). Eventually this increased pressure is back transmitted to the pulmonary arteries. The pulmonary arteries undergo medial hypertrophy and intimal sclerosis in response, and pulmonary arterial hypertension results. Ultimately, the right ventricle hypertrophies, dilates, and then fails. Clinically there is a diastolic murmur and resting tachycardia as the heart attempts to supply more blood systemically. Rarely, patients with mitral stenosis can present with diffuse alveolar hemorrhage . Another rare, late sequella of mitral stenosis is parenchymal ossification . In approximately 0.6% of cases of mitral stenosis, a coexisting ASD may relieve the left atrial hypertension and promote the formation of a left to right shunt. This combination of findings is known as Lutembacher syndrome .
The two major factors influencing prognosis in mitral stenosis are the presence of pulmonary hypertension (triples operative mortality) and the presence of symptoms . Once more than mild symptoms develop, the prognosis for medical treatment decreases .
Etiologies of mitral stenosis include rheumatic heart disease (most commonly), congenital mitral stenosis, or an obstructing lesion such as a left atrial myxoma.
CXR: The left atrial appendage is the only portion of the left atrium that forms part of the left border of the heart. On PA radiographs it occupies the portion of the left heart border between the main pulmonary artery segment and the superior portion of the left ventricular contour. When left atrial pressure and volume are normal, this segment of the left heart border is concave. Early or mild enlargement of the left atrium may be detected as enlargement of the left atrial appendage with straightening of this segment of the left heart border. With continued enlargement, this segment will become convex. Another finding of left atrial enlargement include a "double density" in the mid-portion of the cardiac silhouette on the frontal view. A line from the mid-point of the right border of the double density to the midpoint of the border of the left mainstem bronchus should measure less than 7.5 cm (7.0 cm in females). A normal left atrium should also lie anterior to a line drawn down the center of the trachea on the lateral, non-rotated view. Other findings which can suggest LA enlargement include posterior esophageal displacement on barium swallow, elevation of the left mainstem bronchus, and straightening of the left heart border due to enlargement of the left atrial appendage. In cases of long-standing stenosis, the LA wall may calcify. Mitral valve calcification is only seen 10% of cases (Note: Calcification of the mitral valve annulus does not indicate mitral stenosis). Pulmonary venous congestion can be seen as the stenosis progresses. Since the left ventricle is unaffected by mitral stenosis it will remain normal . Later there is pulmonary arterial hypertension and right ventricular enlargement.
MRI: On MRI other findings of mitral stenosis include a mild increased signal intensity in the lungs on spin echo images due to pulmonary venous hypertension and interstitial edema. Cine gradient images can be used to demonstrate turbulent flow across the mitral valve which appears as a fan-shaped signal void in the LV below the valve during diastole.
Saturday, October 23, 2004
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Wednesday, October 20, 2004
Magnetic resonance imaging (MRI) of the bladder is most frequently used for staging of a known bladder tumor and follow-up of a treated cancer patient. MRI is well suited for bladder evaluations, since it is a noninvasive examination that allows multiplanar visualization of the entire pelvis and offers superior soft-tissue contrast.
Bladder cancer is a common tumor of the urinary tract, accounting for 6% to 8% of male malignancies and 2% to 3% of female malignancies.1 The most common histologic cell type is transitional cell carcinoma, accounting for 90% of all primary tumors of the urinary bladder. The remaining 5% to 10% of malignant bladder tumors are nontransitional and consist of squamous cell carcinomas, adenocarcinomas, small cell carcinomas, and, rarely, sarcomas. Cross-sectional imaging aids in determining tumor stage, including detection of local extension of the tumor, lymph node involvement, and distant metastasis.2 Presently, magnetic resonance (MR) imaging is the modality of choice in imaging of urinary bladder neoplasms, and staging accuracy of MR imaging in bladder cancer ranges from 73% to 96%. These values are 10% to 33% higher than those obtained with computed tomography (CT).3 Because the most common disease of the urinary bladder that requires further imaging is bladder cancer,4 the most frequent indications for MR imaging of the bladder are staging of a known bladder tumor and follow-up of a treated cancer patient. The excellent soft-tissue contrast and multiplanar capability of MR imaging improve the evaluation of the location and extent of bladder tumors.5
Currently, a 1.5T MR scanner with a phased-array pelvic coil is commonly used for imaging of the urinary bladder. The typical urinary bladder protocol includes T1-weighted spin-echo images (repetition time [TR]: 400 to 550 msec; echo time [TE]: minimum) obtained in the axial plane and T2-weighted fast spin-echo (TR: 4000 to 5500 msec; TE: 80 to 120 msec) images also obtained in the axial plane. Subsequently, fast multiplanar spoiled gradient-echo images with fat suppression (TR: 180 to 300 msec; TE:1.7 to 4.2 msec) are obtained in the axial plane before, at 20 seconds (arterial phase), and at 70 to 115 seconds (venous phase) after gadopentate dimeglumine injection (0.1 mmol/kg). Sagittal or coronal T2-weighted images may be obtained, if the anteroposterior or inferosuperior extent of disease needs to be evaluated. Sagittal and coronal gadolinium-enhanced images are also recommended for the evaluation of the bladder tumors, when the tumor is located in the base or the dome of the bladder. Typical parameters for optimal bladder imaging are: 20- to 30-cm ﬁeld-of-view (FOV), 6-mm slice thickness, and 2-mm intersection gap. Ideally, the urinary bladder should be moderately distended during imaging. The low distension may cause misevaluation of the bladder wall thickening, and overdistension may obscure small tumors.
Bladder cancer is more common in men (male/female: 3:1) than in women. It is the fourth most common cancer in men, after prostate, lung, and colorectal cancer, and it accounts for 10% of all cancer cases in men. In women, it is the eighth most common cause of cancer and accounts for 4% of all cancer cases in women.6 It is generally a disease of the elderly, and its incidence peaks at the sixth to seventh decade.7
Several factors predispose patients to bladder cancer. Cigarette smokers are 2 to 6 times more likely to develop urothelial cancer than those who do not smoke.8,9 Cystitis and chronic urinary tract infection are predisposing factors to bladder cancer, and 7% of bladder tumors are found to be associated with diverticuli (Figure 1). Strong association with aniline dyes, aromatic amines, diesel fumes, and long-term use of analgesic phenacetin has been reported in the development of bladder cancer.1
Pathologically, 90% of the bladder tumors are epithelial, and 90% of the epithelial tumors are transitional cell carcinomas. At the time of presentation, 30% of patients have multifocal disease, and there may be widespread areas of metaplasia and carcinoma in situ.1 The remaining 10% of epithelial tumors include squamous cell carcinomas, adenocarcinomas, small cell carcinomas, and, rarely, sarcomas.2 Leiomyosarcoma, rhabdomyosarcoma (Figure 2), phaeochromocytoma, and hamartomatous malformations are among the nonepithelial tumors.1 Gross or microscopic hematuria is the most common clinical presentation, followed by symptoms related to associated urinary infection.10
Staging and management of bladder cancer
Local extension of the tumor (T), lymph node involvement (N), and distant metastasis (M) are the indicators used in staging. Table 1 presents the bladder cancer staging used.11 Treatment options and prognosis depend on the clinical stage of the bladder tumor. It is critically important to differentiate between superﬁcial and invasive disease.1 Superﬁcial tumors are treated with local endoscopic resection, with or without adjuvant intravesical instillations of chemotherapeutic agents; while invasive tumors are treated by curative cystectomy and palliative chemo- and/or radiation therapy.12
Management of bladder tumors starts with clinical staging, including cystoscopic examination of the organ. This method allows for immediate biopsy and can distinguish superﬁcial from invasive tumors, but it is not capable of detecting extravesical disease. This distinction is important because patients with non– organ-conﬁned disease have higher recurrence rates and lower survival rates.13
CT has been a valuable tool for the evaluation of bladder tumors, but MR imaging has been shown to be superior in the detection of superﬁcial and multiple tumors, and in staging accuracy in detecting extravesical tumor extension and surrounding organ invasion, especially with dynamic contrast administration.2,14-20 Accuracy of MR imaging on a stage-by-stage basis has been reported to be between 64% and 85%.16,18,19,21,22 Staging accuracy of MR imaging in differentiating superﬁcially versus deeply muscle-invasive tumors, and organ-conﬁned versus non–organ-con-ﬁned tumors is between 85% and 95%.15,17,21,23
Restaging after treatment is particularly challenging. Intravesical therapy with chemotherapeutic agents is used to treat low-stage tumors. Intravesical therapy may cause bright submucosal enhancement after administration of gadolinium. Previoustransurethral resection or biopsy of the tumor may cause inﬂammation and edema, and this may result in overstaging. Using MR imaging, it is not possible to discriminate by signal characteristics alone between edema resulting from treatment and tumor recurrence, but the presence of a mass with an enhancement pattern typical of a tumor may enable the diagnosis of recurrence.
Tumors can arise anywhere in the bladder, but they are most commonly located in the lateral wall. When a tumor is located around the ureteral oriﬁces, it may produce partial or complete blockage of one or both ureters, resulting in hydroureter and hydronephrosis.10 Tumors manifest a variety of patterns of growth, including papillary, sessile, inﬁltrating, nodular, mixed, and ﬂat intraepithelial growth. Because the bladder does not have a distinct basement membrane, it is difﬁcult to detect the invasion of the lamina propria by imaging .24 However, the detrussor muscle can be well evaluated with MR imaging; therefore, the depth of muscle invasion can be assessed. The fat tissue around the bladder can be seen clearly on MR imaging, and the interface between the bladder wall and the surrounding fat can be evaluated for extravesical tumor spread.
MR imaging features
Urinary carcinomas have intermediate signal intensity, equal to that of muscle on the T1-weighted images. T1-weighted images are used to assess perivesical fat invasion and lymph node involvement. T2-weighted images aid in determining the depth of tumor inﬁltration into the bladder wall. On T2-weighted images, urine has high signal intensity, and the bladder wall appears hypointense. Bladder tumors have the same, or slightly higher, signal intensity as the bladder wall on T2-weighted images. An intact, low-signal-intensity muscle layer at the base of the tumor is classiﬁed as stage Ta or T1 (Figure 3); a disrupted low-signal-intensity muscle layer without inﬁltration of perivesical fat is classiﬁed as stage T2b (Figure 4).25
Urinary bladder carcinomas and their metastases develop neovascularization26; therefore, these tumors enhance earlier than the normal bladder wall.3 In the arterial phase of contrast enhancement, bladder tumors enhance more than the muscle of the bladder (Figure 5). Superﬁcial tumors (those without muscle invasion, stage T1 and lower) may be differentiated from muscle-invasive tumors on contrast-enhanced images. On contrast-enhanced studies, a lesion with an irregular, shaggy outer border, and streaky areas of the signal intensity of the tumor in the perivesical fat is classiﬁed as stage T3b (Figure 6). A tumor extending into an adjacent organ or abdominal and pelvic sidewall with the same signal intensity as the primary tumor is classiﬁed as stage T4a or T4b, respectively (Figure 7).25With the current imaging protocols using 1.5T MR scanners, MR imaging cannot differentiate stage Ta tumors from stage T1; and differentiation of stage T2a tumors (superﬁcial muscle invasion) from stage T2b (deep muscle invasion) is problematic but sometimes can be better delineated on contrast-enhanced studies.2
Based on MR imaging features, it is not possible to differentiate between different histologic cell types of bladder tumors, but few clues may lead to the differentiation of transitional from non–transitional-cell carcinomas. Non–transitional-cell carcinomas are aggressive tumors that usually extend beyond the bladder wall at the time of initial diagnosis, whereas two thirds of transitional cell carcinomas are superﬁcial. Non–transitional-cell carcinomas tend to cause marked bladder wall thickening and tend to be larger than transitional cell carcinomas.27 The non–transitional-cell carcinomas of the bladder include: squamous cell carcinoma, adenocarcinoma, small cell carcinoma, and carcinosarcoma.
Squamous cell carcinoma
Squamous cell carcinoma is the most common non–transitional-cell bladder tumor, accounting for 3% to 7% of all bladder tumors in the United States. Approximately 80% of squamous cell carcinomas in Egypt are associated with chronic infection caused by schistosomiasis (bilharziasis).24The disease is relatively more common in women, unlike transitional cell carcinoma, which is more common in men. The reported female-to-male ratio varies from 1.25:1 to 1.8:1.28 In contrast to transitional cell carcinomas, squamous cell carcinomas are often widespread and involve areas other than the base of the bladder. Most squamous cell carcinomas are solitary and large at the time of detection, with invasion of the muscular wall reported in >80% of patients (Figure 8). Metastases have been identiﬁed in at least 10% of patients at the time of diagnosis. Interestingly, metastases from squamous cell carcinomas of the urinary bladder often occur at sites other than the regional lymph nodes. Common metastatic sites include bone, lung, and bowel.29
Adenocarcinoma of the urinary bladder is uncommon, accounting for 0.5% to 2% of all bladder malignancies.30 Adenocarcinomas are classiﬁed into 3 groups: primary, urachal, and metastatic.24 Like squa mous cell carcinomas, many adenocarcinomas probably occur in reaction to long-term mucosal irritation. Cystitis glandularis, bladder exstrophy, and urachal remnants are also associated with adenocarcinoma of the bladder. Cystitis glandularis has been observed in approximately 50% of adenocarcinoma cases located at the bladder base3,11,24,28,29; however, most au thors do not accept this entity as a predisposing factor for urothelial adenocarcinoma. Adenocarcinoma is observed in <10% of patients with bladder exstrophy, and >80% of urachal neoplasms are adenocarcinomas.29 Signet cell adenocarcinomas characteristically produce linitis plastica of the bladder (Figure 9).
Small cell carcinoma
Small cell carcinoma of the bladder has also been called undifferentiated and poorly differentiated carcinoma. Most small cell carcinomas occur as a component of mixed carcinomas. Age, sex, and symptoms are comparable to those of transitional cell carcinomas. Cystoscopically, small cell carcinomas tend to be polypoid or nodular and often appear as ulcerated masses that cannot be distinguished from other high-grade bladder cancers (Figure 10). Metastatic spread occurs rapidly, and the most frequent sites are the regional lymph nodes, bones, and peritoneal cavity.29
Carcinosarcoma of the urinary bladder is a rare neoplasm; approximately 73 cases have been reported. They are most frequently observed in the female genital tract.31 Neither the etiology nor the pathogenesis of carcinosarcomas is currently known. Unlike transitional cell carcinomas, carcinosarcomas are highly aggressive tumors, with high recurrence rates and a poor prognosis. These tumors can present as large single tumors or multiple small- to medium-sized tumors. The tumors may be polypoid or sessile and may arise from anywhere in the bladder. Location, size, shape, and multiplicity do not help to differentiate carcinosarcomas from transitional cell carcinomas. Dynamic gadolinium-enhanced imaging in carcinosarcomas does not show early strong arterial enhancement, a feature differentiating this tumor from a transitional cell carcinoma. On T2-weighted imaging, the signal intensity of carcinosarcomas can be heterogeneous.32
MR imaging is a noninvasive examination that allows multiplanar visualization of the entire pelvis and offers superior soft-tissue contrast. It is a useful modality for the assessment of tumors of the urinary bladder. Imaging with gadolinium enhancement allows evaluation of the bladder tumor extent and adjacent organ involvement. MR imaging thus plays a critical role in improving staging accuracy, determining patient management, and assessing response to therapy.
Monday, October 18, 2004
Friday, October 15, 2004
Thursday, October 14, 2004
Nonvisualization of the appendix on helical computed tomography (CT) examination is associated with low incidence of acute appendicitis in the absence of secondary inflammatory changes, according to the results of a retrospective study published in the October issue of the American Journal of Roentgenology. Appendicitis may be safely ruled out given the visualization of more than a scant amount of pericecal fat.
"CT has become part of the standard of care in managing patients with suspected acute appendicitis," writes Paul Nikolaidis, MD, from the Department of Radiology at Northwestern University Feinberg School of Medicine in Chicago, Illinois, and colleagues. "Sometimes, however, the appendix is not visualized on CT examination despite the use of optimal imaging parameters."
To assess the significance of nonvisualization of the appendix in the absence of secondary inflammatory changes, the investigators retrospectively reviewed CTs taken to rule out appendicitis in 366 consecutive patients presenting with symptoms of lower abdominal or right lower quadrant pain.
Original CT reports included 56 CTs (15%) in which the original reviewer was unable to visualize the appendix in the absence of secondary inflammatory changes, including abscess formation, localized perforation, periappendiceal fat stranding, or appendicolith.
The investigators were able to visualize appendices in 10 of these CTs upon review, yielding 46 CTs (13%) in which nonvisualization of the appendix was agreed upon. Pericecal fat was evaluated on a scale of 0 (scant, n = 8), 1 (n = 20), and 2 (abundant, n = 28).
In 12 patients (26%), CT indicated gastrointestinal (n = 8) and genitourinary (n = 4) symptom sources. Of 34 remaining patients, 11 (24%) were diagnosed through further imaging or clinical evaluation. One patient (2%) with a scant amount of pericecal fat (score = 0) was diagnosed with acute appendicitis that was confirmed by surgical pathology.
"The amount of fat surrounding the cecum influences our ability to visualize the appendix and therefore more confidently exclude the possibility of acute appendicitis," the authors write, pointing out the scant amount of pericecal fat (score of 0) in the patient with the missed diagnosis.
Study limitations include its retrospective nature and the lack of follow-up information for a relatively large number of patients (50%).
"In the absence of a distinctly visualized appendix and secondary inflammatory changes, the incidence of acute appendicitis is low (2%)," the authors conclude, adding that acute appendicitis may be safely excluded with CT visualization of more than a scant amount of pericecal fat.
Am J Roentgenol. 2004;183:889-892
Wednesday, October 13, 2004
Applications are invited from Indian citizens who have passed their final MBBS examination in the first or second attempt, and have completed their internship.The Commission tenure lasts for five years, and can be extended by another five. Eligibility Criteria-medical qualification that is included in First/Second Schedule or Part I of the Third Schedule of the IMC Act 1958. -permanent registration from any State Medical Council/ MCI.-Post Graduate Degree holders -- MD, MS, MCh, DM -- in the following subjects will be given preference: AnaesthesiaSurgeryRadiologyObstetrics & GynaecologyMedicine-under 45 years old as on December 31.ImportantYou cannot apply if you have taken more than two chances in your final MBBS examinations. How to applyFor admission forms, please contact: Office of the Director General Armed Forces Medical Services/DG-1AMinistry of Defence'L' BlockNew Delhi 110 001.-You are requested to enclose a non-refundable demand draft of any nationalised bank for Rs 200 payable at New Delhi in favour of the Director General Armed Forces Medical Services (APF Fund). -Please write your name and address at the back of the demand draft.-Please ensure that the demand draft bears the code number of the issuing bank.-Please include a self-addressed stamped envelop (4" x 9") to be intimated about the date of interview.Completed forms must reach the above address by October 21. Selection procedureSelected candidates will be called for an interview -- in November-December -- by a Board of Officers at: Director General Armed Forces Medical ServicesMinistry of Defence'M' BlockNew Delhi.If you are appearing for this interview for the first time, you will be paid round trip second-class railway/ bus fares.
Tuesday, October 12, 2004
Least radiosensitive tissue of body-Nervous tissue/Brain
Most radiosensitive blood cell-lymphocyte
Least radiosensitive blood cell-Platelet
Most common organ to be affected by radiation-skin(erythema earliest change)
Most radioresistant organ-vagina
Most common mucosa to be affected by radiation-Intestinal mucosa
Monday, October 11, 2004
Hydrocephalus is the accumulation of cerebrospinal fluid in the brain, resulting from increased production or, more commonly, pathway obstruction or decreased absorption of the fluid. CSF shunts have been used for decades for the treatment of hydrocephalus. CSF shunting involves establishing an accessory pathway for the movement of CSF in order to bypass an obstruction of the natural pathways.
The shunt is positioned to enable the CSF to be drained from the cerebral ventricles or subarachnoid spaces into another absorption site (e.g., the right atrium of the heart or the peritoneal cavity) through a system of small catheters. A regulatory device, such as a valve, may be inserted into the pathway of the catheters.
In general, the valve keeps the CSF flowing away from the brain and moderates the pressure or flow rate. Some valves are fixed pressure valves (i.e., monopressure valves), and others have adjustable settings. The drainage system using catheters and valves enables evacuation of the excess CSF within the brain and, thereby, reduction of the pressure within the cranium.
Several different types of CSF shunt valves and associated accessories are used for treatment of hydrocephalus. Information for certain CSF shunt valves is provided at the end of this monograph. In general, shunt valves that use magnetic components require following highly specific safety guidelines to perform MR procedures safely in patients with these devices.
CODMAN HAKIM PROGRAMMABLE VALVE
The CODMAN HAKIM Programmable Valve (Codman, Raynham, MA) offers the ability to optimize the opening pressure of a shunt system before and after implantation. This is considered to be an important feature because the shunted patient's condition will often change over the course of treatment. The use of a programmable valve allows the surgeon to noninvasively change the opening pressure, negating the need for revision surgery to alter the valve pressure. Furthermore, the programmability of the valve may allow for the development of specialized treatment regimens.
The opening pressure of the CODMAN HAKIM Programmable Valve is changed through the use of an externally applied magnetic field. The spring in the ball and spring mechanism of the valve sits atop a rotating spiral cam that contains a stepper motor. Applying a specific magnetic field to the stepper motor will cause the cam to turn slightly, increasing or decreasing the tension on the spring and ball, thus changing the opening pressure of the valve.
With regard to MRI, the product insert for the CODMAN HAKIM Programmable Valve states: "Note: Remember to verify valve pressure setting after an MRI."
DELTA SHUNT ASSEMBLY
The Delta Shunt Assembly (Medtronic Neurosurgery, Goleta, CA) combines the Delta valve with an integral, open-end, radiopaque peritoneal catheter. All Delta shunt assemblies incorporate the same product features as the Delta valves. These include injectable reservoir domes, occluders for selective flushing, and a completely nonmetallic design. The valves are fabricated of dissimilar materials -- polypropylene and silicone elastomer -- reducing the chance of valve sticking and deformation.
The normally closed Delta chamber mechanism minimizes overdrainage by utilizing the principles of hydrodynamic leverage. Because of the nonmetallic design, the Delta shunt is safe for patients undergoing MR procedures.
POLARIS ADJUSTABLE PRESSURE VALVE
The POLARIS Adjustable Pressure Valve (Sophysa USA, Costa Mesa, CA) has magnets made of Samarium-Cobalt, which are specially treated to preserve permanent magnetization even after repeated exposure to MR at 3T. The principle of the POLARIS Adjustable Pressure Valve is based on the variation in pressure exerted on a ball by a semicircular spring at different points along its curvature. The flat semicircular calibrated spring determines an operating pressure. Because of the unique design of the POLARIS Adjustable Pressure Valve, it is considered to be safe for patients undergoing MR procedures at 3T or less.
The Pulsar Valve (Sophysa USA, Costa Mesa, CA) for CSF drainage is a monopressure valve. Its principle is based on the play of a silicone membrane, calibrated in low, medium, or high pressure, ensuring a proximal regulation of CSF flow through the shunt system. The Pulsar Valve is safe for patients undergoing MR procedures.
SOPHY MINI MONOPRESSURE VALVE
The Sophy Mini Monopressure Valve (Sophysa USA, Costa Mesa, CA) for CSF drainage has a ball-in-cone mechanism. This device is safe for patients undergoing MR procedures.
The PS Medical Strata Valve (Medtronic Neurosurgery, Goleta, CA) is an adjustable flow control valve in which the resistance properties of the valve can be changed noninvasively by the caregiver. It is designed to minimize overdrainage of CSF and maintain intraventricular pressure within a normal physiologic range, regardless of patient position.
Extensive testing of the Strata Valve was conducted using MR with a static magnetic field of 1.5T. Results of the testing indicated that the valve is "MR-Safe." That is, exposure of the valve to MR scanning will not damage the valve, but it may change the valve's performance level setting. Therefore, after MR exposure, the valve performance level setting needs to be confirmed and adjusted as necessary.
From a diagnostic standpoint, the presence of the Strata valve in a patient may disrupt or impair the use of MR if the area of interest is near the location of the valve (personal communication, 9/17/04, Karen Rhodes, manager, Medtronic Neurosurgery, Goleta, CA).
SOPHY ADJUSTABLE PRESSURE VALVE
The principle of the SOPHY Adjustable Pressure Valve (Sophysa USA, Costa Mesa, CA) resides in the variation in pressure exerted on a ball by a semicircular spring at various points along its circumference. The spring is attached to a magnetic rotor whose position can be noninvasively altered using an adjustment magnet. A series of indentations allows a variety of positions to be selected, each position representing a different pressure setting. The valve's ball-in-cone mechanism maintains the selected pressure constant without significant drift through the time.
Because a magnetic component is associated with this device, special MR safety precautions exist for scanning patients with the SOPHY Adjustable Pressure Valve:
The pressure settings should always be checked in case of shock on the implantation site.
Changing pressure settings must only be performed by a neurosurgeon.
The patient must be advised that carrying his or her patient identification card is important and necessary for follow-up of clinical conditions.
Patients undergoing MR exposure should be advised that they might feel a small yet harmless effect due to MR.
The pressure settings should always be checked before and after MR exposure or after strong magnetic field exposure.
The patient must be advised that in the case of implantation on the skull, vibrations due to CSF flow may be perceived.
Patients with implanted valve systems must be kept under close observation for symptoms of shunt failure.
[For these devices, MR healthcare professionals are advised to contact the respective manufacturer to ensure that the latest information is obtained and carefully followed in order to ensure patient safety.]
Cerebral spinal fluid shunt valves and accessories. Raynham, MA: Codman. http://www.codmanjnj.com/CSFshunting.asp.
Cerebral spinal fluid shunt valves and accessories. Raynham, MA: Codman. http://www.codmanjnj.com/PDFs/Prog_ProcedureGuide.pdf.
Cerebral spinal fluid shunt valves and accessories. Goleta, CA: Medtronic Neurosurgery. http://www.medtronic.com/neurosurgery/shunts.html.
water lily sign
TB kidney/Putty kidney
Picture frame vertebra
Golden's S sign
Iscaemic colitis-thumb printing
Dandy walker syndrome
Antenatal USG-Polycystic kidneys
Pulmonary Secondaries with absent right breast shadow (following mastectomy)
CLOSED LIP SCHIZENCEPHALY WITH HETEROTOPIC GRAY MATTER
Antenatal US-Esophageal Atresia
A posteroanterior and lateral chest film should be obtained primarily to exclude competing diagnoses. They may be entirely normal in mild disease. As COPD progresses, abnormalities reflect emphysema, hyperinflation, and pulmonary hypertension. Emphysema is manifested by an increased lucency of the lungs. In smokers, these changes are more prominent in the upper lobes, while in a1AT deficiency, they are more likely in basal zones. Local radiolucencies >1 cm in diameter and surrounded by hairline arcuate shadows indicate the presence of bullae and are highly specific for emphysema. With hyperinflation, the chest becomes vertically elongated with low flattened diaphragms. The heart shadow is also vertical and narrow. The retrosternal airspace is increased on the lateral view, and the sternal-diaphragmatic angle exceeds 90°. In the presence of pulmonary hypertension, the pulmonary arteries become enlarged and taper rapidly. The right heart border may become prominent and impinge on the retrosternal airspace. The presence of "dirty lung fields" may reflect the presence of bronchiolitis.
Computed tomography has greater sensitivity and specificity for emphysema than the plain film but is rarely necessary except for the diagnosis of bronchiectasis and evaluation of bullous disease. Nonhomogeneous distribution of emphysema is thought by some to be an indicator of suitability for lung volume reduction surgery (LVRS).
Sunday, October 10, 2004
Holoprosencephaly is a complex intracranial abnormality characterized by absent or incomplete cleavage of the Prosencephalon (1).From a genetic point of view all holoprosencephalies have the same significance. Their frequency is estimated at 1 in 16,000 to 1 in 18,000 births (2).Holoprosencephalies have a heterogenous cause; chromosomal aberration is found in about one half of the cases. Chromosome 13 is most frequently involved. Partial deletion of chromosome 13 as well as trisomy may coexist with Holoprosencephalies. (2) Holoprosencephaly as, an autosomal dominant inheritance is rare but certainly exists. Recurrence risk after an isolated case of holoprosencephaly with normal chromosome is 5-6% (3).During the fourth gestational week, the neural tube forms three primary brain vesicles: the prosencephalon, mesencephalon and rhombencephalon. During the fifth week the forebrain (Prosencephalon) further divides into secondary vesicles: the telencephalon and diencephalons. Partial division of the telencephalon into two cerebral hemisphere occurs by the end of the fifth fetal week. Complete or partial failure in division of the developing cerebrum (Prosencephalon) into hemispheres and lobes results in the Holoprosencephalies. (4)Alobar form is rare malformation consisting of large Holospheric Brain. Alobar holoprosencephaly is characterized by nearly complete lack of ventricular and hemispheric cleavage. The Brain is basically an undifferentiated Holosphere with central monoventricle and fused thalami (4). 17% cases of Holoprosencephaly are reported with no facial anomaly (5).
Macahan PJ, Nyberg AD, Mack AL. Sonography of facial feature of alobar and semi lobar Holoprosencephaly. AJR, 1990:154:143-148.
Barness EG.Prosencephalon Growth Failures. Potter's Pathology of the Foetus And Infants.3rd Ed: Vol 2:Mosby: 1997:1056-1059.
Baraister M, Winter RM. Holoprosencephaly.Color atlas of Congenital Malformation Syndrome.Mosby: 1996:148.
Osborn AG. Disorders of Diverticulation and Cleavage, Sulcation and Cellular Migration. Diagnostic Neuroradiology.1st Ed: Vol 1:Mosby, 1994:37-39.
Dahnert WG, Radiology Review Manual. 3rd Ed: Williams &Wilkins, 1996:213-214.
Ind J Radiol Imag 2003 13:3:295-296
PURPOSE: To prospectively evaluate use of dynamic contrast material–enhanced magnetic resonance (MR) urography for measurement of renal transit time (RTT) of a contrast agent through the kidney and collecting system so as to identify obstructive uropathy in children.
MATERIALS AND METHODS: One hundred twenty-six children suspected of having hydronephrosis were hydrated prior to undergoing both conventional and dynamic contrast-enhanced MR urography of the kidneys and urinary tract. A three-dimensional sequence was used to track passage of contrast agent through the kidneys. Time between the appearance of contrast material in the kidney and its appearance in the ureter at or below the level of the lower pole of the kidney was defined as RTT. Bland-Altman plots were used to quantify intra- and interobserver performance. In 30 children, a nuclear medicine renogram was also obtained, and the half-life of renal signal decay after furosemide administration was derived and compared with the MR imaging RTT by using receiver operating characteristic curves.
RESULTS: On the basis of RTT, kidneys were classified as normal (RTT 245 seconds), equivocal (245 seconds > RTT 490 seconds), or obstructed (RTT > 490 seconds). Inter- and intraobserver agreement indicated that the technique is both robust and reproducible. Receiver operating characteristic analysis for comparison of results of MR imaging and diuretic renal scintigraphy showed good agreement between the modalities, with a mean area under the curve of 0.90.
CONCLUSION: When used in conjunction with morphologic images obtained in the same examination, RTT generally allowed normal kidneys to be differentiated from obstructed and partially obstructed kidneys.
While estimates of the frequency of müllerian duct anomalies vary widely owing to different patient populations, nonstandardized classification systems, and differences in diagnostic data acquisition, these anomalies are clinically important, particularly in women who present with infertility. An understanding of the differences between these uterovaginal anomalies, as outlined in the most widely accepted classification system—that published by the American Fertility Society (AFS) in 1988—is imperative given the respective clinical manifestations, different treatment regimens, and prognosis for fetal salvage. Although the AFS classification system serves as a framework for description of anomalies, communication among physicians, and comparison of therapeutic modalities, there often is confusion about appropriate reporting of certain anomalies, particularly those with features of more than one class. Many of the anomalies are initially diagnosed at hysterosalpingography and ultrasonography; however, further imaging is often required for definitive diagnosis and elaboration of secondary findings. At this time, magnetic resonance imaging is the study of choice because of its high accuracy and detailed elaboration of uterovaginal anatomy. Laparoscopy and hysteroscopy are reserved for women in whom interventional therapy is likely to be undertaken.
Proteus syndrome is a sporadic disorder named for its highly variable manifestations. The disease causes tissue overgrowth in a mosaic pattern and may affect tissues derived from any germinal layer. The disease process is not usually apparent at birth but develops rapidly in childhood. Common manifestations include macrodactyly, vertebral abnormalities, asymmetric limb overgrowth and length discrepancy, hyperostosis, abnormal and asymmetric fat distribution, asymmetric muscle development, connective-tissue nevi, and vascular malformations. The features of Proteus syndrome indicate that the condition may be caused by a somatic alteration in a gene, but no specific genetic mutation has yet been identified. Therefore, the diagnosis and management of the disease depend heavily on clinical evaluation and imaging. Although the manifestations of Proteus syndrome are highly variable, accurate diagnosis is possible if standard diagnostic criteria are followed and if disease features are assessed in comparison with those found in similar syndromes.
Saturday, October 09, 2004
RSNA 2004 to Feature Focus Session on Medical Simulators
In order to perform procedures such as carotid stenting, you have to demonstrate a certain level of proficiency. The way to increase your proficiency is through medical simulation.— Anthony G. Gallagher, Ph.D.
Picture this: Medical students stand around a patient in an emergency room setting. The patient complains of severe abdominal pain. Following a diagnosis of sigmoid volvulus, a student injects a bolus of 10 mg morphine. The patient develops respiratory arrest and nearly dies. The patient is reprogrammed for the next lesson.
The patient isn't real. It is a high-fidelity medical simulator that talks, blinks, breathes and moves just like a real patient. Physiologic data, including heartbeat, oxygenation and blood pressure are displayed on a real-time cardiac monitor, alongside customized laboratory results and imaging studies. This particular scenario is part of an educational module created in the late 1990s by Harvard anesthesiologists John Pawlowski and Marty Gallagher at the Center for Medical Simulation in Boston.
Working with the Center, James A. Gordon, M.D., M.P.A., an emergency physician at Massachusetts General Hospital, now directs the new G.S. Bechwith Gilbert and Katharine S. Gilbert Medical Education Program in Medical Simulation at Harvard Medical School.
"Simulation is to medical education what the microscope was to science," says Nancy Oriol, M.D., Harvard's associate dean for student affairs. Originally costing up to $200,000, full-body patient simulators are now available for under $50,000.
Gary J. Becker, M.D., RSNA Board Liaison for Science and branch chief of image-guided intervention for the Cancer Imaging Program at the National Cancer Institute, agrees that medical simulators represent the future of medical education. "Following the exercise previously described, the students learned that they should have applied book knowledge in the emergency room," he says. "In the heat of battle, no one thought to reverse the effects of morphine sulfate with IV Narcan. This example of a tangible experience, with failure to recall and implement a life-saving treatment, is arguably a much better teaching method than a textbook."
At RSNA 2004 a hot topic focus session will be held on Wednesday, December 1 to highlight the use of medical simulators to educate radiologists—especially interventional radiologists. The session will also demonstrate how to use medical simulators to problem-solve in various medical scenarios.
One of the presenters, Anthony G. Gallagher, Ph.D., from Emory University, co-authored the first randomized, double-blinded study of virtual reality simulation in the training of surgical residents. The 2002 study demonstrated that residents trained on simulators to perform laparoscopic cholecystectomy performed 30 percent faster and were six times less likely to have intraoperative errors. Dr. Gallagher says a follow-up study with more complete data will be presented this month at the American College of Surgeons clinical congress.
"Minimally invasive procedures, especially image-guided interventions, are changing medicine," says Dr. Gallagher. "What we're seeing in carotid stenting is the convergence of interventional radiology, interventional cardiology, and vascular and neurovascular surgery. The FDA says that in order to perform procedures such as carotid stenting, you have to demonstrate a certain level of proficiency. The way to increase your proficiency is through medical simulation. This is a huge paradigm shift in medicine."
Focus session moderator Steven L. Dawson, M.D., an associate professor of radiology at Harvard, says medical education must be modernized. "Medicine is using the same teaching model that Egyptians used 4,000 years ago. If I'm a doctor in a teaching hospital and a sick person comes in, I learn while treating that person. If I need to learn how to treat a particular disease and no one with that disease shows up, I'm out of luck."
He adds that the system may have worked fine for many years, but times have changed. "We are in a crucial time in medical education where revolutions in computing, mathematics, engineering and education surround us," Dr. Dawson says. "Our challenge is to grab the best of these revolutions and create a new way of medical learning. Prototyping new procedures in silico gives a whole new meaning to the phrase, 'the practice of medicine.'"
Dr. Gordon will also participate in the focus session. His educational model of "full-body, immersive simulation" strives to replicate a full clinical encounter between a physician and a patient. He and his colleagues work with a robot-mannequin named "Stan," short for standard patient.
"The purpose of full-body patient simulation in my own work is to recreate a provider's emotional reaction to the care process," explains Dr. Gordon, who is an inaugural member of the Board of Overseers of the new Society for Medical Simulation. "In doing so, students using the simulator can integrate and remember material in a powerfully instructive way. Imagine a group taking care of Stan, who is having a heart attack and complains, 'Doctor, my chest hurts.' In the midst of the encounter, you could show the students a coronary angiogram to demonstrate the blocked artery. By juxtaposing 'real-time' diagnostic images alongside simulated clinical encounters, I think students can more easily integrate relevant anatomy and radiology with overall patient care."
The RSNA 2004 focus session will familiarize attendees with the state of the art of simulation and raise awareness of the concept's full potential.
Dr. Becker says medical simulators can be beneficial in:
Medical student education
Aptitude testing for specialty training
Specialty-specific clinical scenarios in residency training (e.g., response to life-threatening contrast reactions in radiology)
Procedure training—imparting essential skills, impacting the learning curve, reducing errors
Addition of advanced skills to basic ones already acquired (e.g., learning new procedures, such as carotid stenting, on a background of basic skills in angiography, angioplasty, stenting, etc.)
Re-credentialing in hospitals
Assessment (e.g., board examinations)
Maintenance of skills (practice hours logged in, as on a flight)
Practice improvement/quality assurance
"As a trustee for the American Board of Radiology (ABR), I envision the possibility of assessing a physician's ability to do a procedure," says Dr. Becker. "When a radiologist comes in for an oral exam, instead of showing an image and discussing how the patient would be managed, we could have the radiologist actually care for the patient."
Dr. Becker says medical simulation training also can help to counter the effects of the 80-hour workweek limits for residents. "There's a substantial and measurable decrease in the experience that residents are now getting," says Dr. Becker, who cites information from Boston Children's Hospital that there's been a 33 percent decline in the number of procedures performed by otolaryngology residents since the new work rules took effect. "Medical simulators could play a role to help this situation."
Dr. Becker proposes that radiology create a strategic approach to medical simulation with help from educators, RSNA staff and volunteers, academics, the simulation industry and ABR representatives. "Without a high level of commitment and an overarching approach, radiology is in danger of being left in the dust of other medical specialties," says Dr. Becker. "Emergency medicine, anesthesia and surgery embraced the topic a long time ago. Interventional cardiology is now on board as well. Although they are ahead of us, there is so much still to be done that we can certainly catch up if we seize the opportunity. But we will need a significant investment of time, energy and resources, as well as a thoughtful strategic approach that makes sense for the entire discipline."
RSNA's belief that medical simulator technology will play an increasingly important role in radiology education has resulted in a collaborative workgroup involving RSNA and the Society of Interventional Radiology.
Steven L. Dawson, M.D. (left), helps a student learn how to place a chest tube into a simulated patient. The monitor shows a representation of the internal position of the tube on an augmented display.
A hands-on exhibit on medical simulation will be featured at RSNA 2004 in the infoRAD area. For more information about the exhibit or about the hot topic focus session, "Is Medical Simulation a Part of Your Future? Education in the Era of Patient Safety," go to rsna2004.rsna.org and click on Meeting Program in the left-hand column. Also see the RSNA.org column for a mini-tutorial on how to use the online RSNA Meeting Program.
(Robert Whitaker, 20th century, English urologist), percutaneous insertion of a canula into the renal pelvis with perfusion of contrast at a rate of 10 ml/minute and simultaneous recording of pressure in the renal pelvis and bladder to identify the presence of obstruction in doubtful cases. In children, the examination is performed under general anaesthetic and instead of a canula two fine needles are inserted. The infusion of contrast allows a simultaneous antegrade pyelography.....
Academic Press Journal Catalog
Institute of Physics Publishing
MedWeb: List of Electronic Newsletters and Journals.
Science.komm: Directory of links to radiology, oncology, and imaging journals.
Advance for Administrators in Radiology and Radiation Oncology
British Medical Journal
Diangostic Imaging Magazine
ECHOnet: Telematic Cardiovascular Imaging Magazine
Estimation of Blood Velocities Using
Ultrasound A Signal Processing Approach
European Journal of Ultrasound
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
IEEE Transactions on Medical Imaging
Journal of the Acoustical Society of America
Journal of Clinical Ultrasound
Journal of Digital Imaging
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Medical Engineering and Physics
Obstetric Safety References
On-line Journal of OB/Gyn Ultrasound
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Physics in Medicine and Biology
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Radiology Resource Guide & Medical Imaging Directory
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The Doctor Is In
The Examining Room of
1. Cobalt 60 is:
A. Naturally occurring radioisotope
B. Artificial radioisotope
C. Product of plutonium
D. Product of uranium
2. Safest light used in darkroom in an X-ray department is:
A. Dull white
3. Honey comb appearance on X-ray is seen in all except:
A. Rheumatoid arthritis
B. Tuberous sclerosis
C. Histiocytosis X
D. Wegener’s granulomatosis
4. Vessels catheterized on carotid angiography are:
A. 2 external carotids and 2 vertebral
B. 2 internal carotids and 2 vertebral
C. 2 internal carotids and 1 vertebral
D. 2 external carotids and 1 vertebral
5. X-rays are formed when electrons hit:
C. Radium source
D. None of the above
Friday, October 08, 2004
A chylothorax occurs when the thoracic duct is disrupted and chyle accumulates in the pleural space. The most common cause of chylothorax is trauma, but it also may result from tumors in the mediastinum. Patients with chylothorax present with dyspnea, and a large pleural effusion is present on the chest radiograph. Thoracentesis reveals milky fluid, and biochemical analysis reveals a triglyceride level that exceeds 110 mg/dL. Patients with chylothorax and no obvious trauma should have a lymphangiogram and a mediastinal computed tomographic (CT) scan to assess the mediastinum for lymph nodes. The treatment of choice for most chylothoraces is implantation of a pleuroperitoneal shunt. Patients with chylothoraces should not undergo prolonged tube thoracostomy with chest tube drainage because this will lead to malnutrition and immunologic incompetence.
Radiology of Pulmonary Tuberculosis:
• Ghon’s lesion: Subpleural consolidation + lymphatic + enlarged lymph nodes
• Lymphadenopathy is characteristic of primary infection ( also in Tuberculosis with AIDS)
• Consolidation can occur anywhere in the lung. (More common subpleural sites in lower lobe)
• Involves Apical segments of upper and lower lobes
• V. UN COMMON IN ANTERIOR SEGMENT OF UPPER LOBE**
Hematogenous spread of TB leads to miliary shadowing
Endobronchial spread : Tree in bud appearance**
Rasmussen aneurysm: Pulmonary artery in cavity TB may cause hemoptysis**
—In hemoptysis—First vessel to be studied-Bronchial artery.
Pneumococcal- more commonly basal, klebsiella more common right upper lobe, bulging fissure, mycoplasma earliest CXR change is fine reticulo-nodular shadows followed by consolidation. Viral pneumonias may show-peribronchial shadowing, reticulonodular shadows and consolidation
• Klebsiella pneumonia (Freidlander’s bacillus)
• Lung abscess
• Ca bronchus
• No or rare calcification in lung
• ‘Water lily’ sign OR CAMALOTE SIGN**
Hydatid cyst forms three layers:
Pericyst due to fibrous host reaction, ectocyst and the endocyst containing brood capsules.
ASPERGILLOSIS IN LUNG
CXR show density surrounded by air in the cavity (air crescent sign)
Also seen in –
AIR Crescent sign
• Aspergilloma or fungal ball
• Inspissated pus in a cavity
• Tumour or clot within the cavity
• Hydatid cyst.
2) Invasive aspergillosis
In immunocompromised persons
CT Halo appearance due to surrounding haemorrhagic inflammation.
3) Allergic bronchopulmonary aspergillosis type III immune reaction, central bronchiectasis, ‘gloved finger appearance’
CXR normal in 10% may show perihilar and mid/lower zone ground glass infiltrates, lymphadenopathy pleural effusion less common. Pneumothorax is well recognized complication.
Morphological Types(increasing severity)
Radiological Signs **
· ‘Signet-ring’ sign- bronchus is larger than the accompanying vessel
· Tram track sign- Lack of peripheral tapering (cylindrical bronchiectasis)
· String of beads appearance alternate dilatation and constriction (varicoid bronchiectasis)
· Cluster of grapes appearance (cystic bronchiectasis)
Ø Investigation of choice: HRCT**
Ø Central Bronchiectasis is a Sign of Allergic Bronchopulmonary Aspergillosis (ABPA) **
Ø Idiopathic disease showing tracheobronchomegaly is mounier-kuhn syndrome.
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