Wednesday, March 30, 2005

Ferucarbotran-Enhanced MRI Versus Triple-Phase MDCT for the Preoperative Detection of Hepatocellular Carcinoma.

Kim SH, Choi D, Kim SH, Lim JH, Lee WJ, Kim MJ, Lim HK, Lee SJ.

OBJECTIVE: We compared ferucarbotran-enhanced MRI with triple-phase MDCT for the preoperative detection of hepatocellular carcinoma.
SUBJECTS AND METHODS: Seventy-three consecutive patients with 121 hepatocellular carcinomas underwent ferucarbotran-enhanced MRI, including a dynamic study, and triple-phase MDCT before hepatic resection. The diagnosis of hepatocellular carcinoma was confirmed in all patients by means of pathologic examination after surgical resection. Three experienced radiologists independently reviewed the MR and CT images on a segment-by-segment basis. The accuracy of these techniques for the detection of hepatocellular carcinoma was assessed by conducting a receiver operating characteristic (ROC) analysis of the observations of 88 resected hepatic segments with at least one hepatocellular carcinoma each and 121 resected hepatic segments without hepatocellular carcinoma.
RESULTS: The mean values of the area under the ROC curve (A(z)) for ferucarbotran-enhanced MRI and triple-phase MDCT for all observers were 0.947 and 0.949, respectively; the difference between these two values was not statistically significant (p = 0.799). The mean sensitivities of MRI and triple-phase MDCT were 90.2% and 91.3%, respectively, and their mean specificities were 97.0% and 95.3%, respectively. The differences in the mean sensitivities and specificities of these two imaging techniques were not statistically significant (p > 0.05 in each case).
CONCLUSION: Ferucarbotran-enhanced MRI seems to be as accurate as triple-phase MDCT for the preoperative detection of hepatocellular carcinoma.

AJR Am J Roentgenol. 2005 Apr;184(4):1069-76.

MR angiography of the carotid arteries using 3 different techniques: Accuracy compared with intraarterial x-ray angiography & endarterectomy specimens

Fellner C, Lang W, Janka R, Wutke R, Bautz W, Fellner FA.

PURPOSE: To compare three different magnetic resonance angiography (MRA) techniques with x-ray angiography and endarterectomy specimens.
MATERIALS AND METHODS: Twenty-one patients underwent x-ray angiography, three-dimensional time-of-flight (TOF) focusing on the carotid bifurcation, high-resolution (HR) contrast-enhanced (CE) MRA, and time-resolved CE MRA. Stenoses of internal carotid arteries were evaluated by three independent observers on identical projection of x-ray angiography and MRA. Maximum stenosis grades on MRA were assessed additionally and correlated with endarterectomy specimens in 12 cases.
RESULTS: Sensitivity for the detection of severe stenoses was excellent (100%) for all MRA techniques, and specificity was superior for three-dimensional TOF (96.7%) compared with HR CE MRA (80.6%) and time-resolved CE MRA (83.9%). The correlation between x-ray angiography and MRA for all stenoses was slightly superior for three-dimensional TOF and HR CE MRA compared with the time-resolved technique (kappa = 0.87 and 0.86 vs. 0.84). The same trend was seen for the interobserver agreement and for the correlation with endarterectomy specimens. Eleven up to 17 stenoses (depending on the MRA technique) were graded higher using additional projections.
CONCLUSION: Three-dimensional TOF MRA yielded even more accurate results than HR CE MRA in grading of stenoses near the carotid bifurcation. Therefore, a combination of both methods seems to be advantageous.

J. Magn. Reson. Imaging 2005;21:424-431.

Saturday, March 26, 2005

Tutorial-ear cartilage calcification

Causes-

Most common-frost bite
Alkaptonuria
Cushing syndrome
Addisons disease
Relapsing polychondritis


From- Review of Radiology-second edition by Sumer K Sethi,Peepee publishers

Thursday, March 24, 2005

Comparison of full-field digital mammography and film-screen mammography: image quality and lesion detection.

Fischmann A, Siegmann KC, Wersebe A, Claussen CD, Muller-Schimpfle M.

The objective of this study is to compare image quality and lesion detection for full field digital mammography (FFDM) and film-screen mammography (FSM). In 200 women we performed digital mammography of one breast and film-screen mammography of the other breast. Imaging parameters were set automatically. Image quality, visualization of calcifications and masses were rated by three readers independently. Mean glandular dose was calculated for both systems. We found no significant difference in mean glandular dose. Image quality was rated by reader A/B/C as excellent for FFDM in 153/155/167 cases and for FSM in 139/116/114 cases (p less than 0.03/0.001/0.001). FFDM demonstrated improved image quality compared with film-screen mammography. Microcalcification detection was also significantly better with the digital mammography system for two of the three readers.

Br J Radiol. 2005 Apr;78(928):312-5.

Monday, March 21, 2005

Dose implications of fluoroscopy-guided positioning (FGP) for lumbar spine examinations prior to acquiring plain film radiographs.

Saunders M, Budden A, Maciver F, Teunis M, Warren-Forward H.

Fluoroscopy is increasingly being used as a positioning device prior to obtaining plain film radiographs. This is particularly true for those examinations where the type of projection and habitus of the patient present difficulties. An example is the examination of the lumbar spine; especially the L5/S1 projection. The purpose of this study was to determine the effect of fluoroscopy-guided positioning (FGP) on patient dose. The study assessed the difference in dose-area product (DAP) between conventional film-screen radiography (FSR) and a FGP assisted series of the lumbar spine. DAP values were monitored on 102 patients (50 FSR, 52 FGP) over 7 (4 FSR, 3 FGP) study sites. The median values for all FGP and FSR procedures were 8.3 Gy cm(2) and 12.5 Gy cm(2), respectively. The differences in doses were attributed to lower mAs and tighter collimation used in FGP assisted procedures. The study has demonstrated that it is possible to achieve lower DAP values using FGP. What now has to be asked is whether FGP should be acknowledged and further introduced into clinical practice. If so, there is a need for careful monitoring and reporting of dose so that strict protocols can be set in place to ensure the ALARA principle is enforced.

Br J Radiol. 2005 Feb;78(926):130-4.

Thursday, March 17, 2005

Journal Club- Colour Doppler ultrasonography replacing surgical exploration for acute scrotum: myth or reality?

Lam WW, Yap TL, Jacobsen AS, Teo HJ.

Background: Traditionally, every patient with an acute scrotum needed surgical exploration for definitive exclusion of testicular torsion. Objective: In this study, we aimed to evaluate the improved accuracy in clinical diagnosis with colour Doppler Ultrasonography (US) added to normal clinical assessment.
Materials and methods: We retrospectively reviewed 626 patients, who presented with acute scrotal pain between January 1998 and June 2004. Following history and physical examination, the patients either proceeded directly to surgery or underwent US examination. If clinical suspicion of testicular torsion persisted after US, the patients would still undergo scrotal exploration.
Results: Of the 294 patients who had routine scrotal exploration without preliminary US, only 23 (7.8%) were found to have testicular torsion. Amongst the 332 cases that had initial US, 9 (2.7%) patients revealed testicular torsion that was confirmed at subsequent surgery. The remaining 323 patients had initial negative US, but 29 were explored eventually on clinical indications. Of these, 4 (1.2% of 323) cases were diagnosed intra-operatively as testicular torsion. None of the remaining 294 patients who were managed conservatively proved to have testicular torsion after a minimum follow-up of 2 weeks. For testicular torsion, US yielded a sensitivity of 69.2% (95% confidence interval =38.9-89.5), specificity of 100% (95% CI=98.5-100), positive predictive value of 100% and negative predictive value of 97.5%.
Conclusions: US has proven to decrease the number of emergency scrotal explorations, length of hospital stay and hence reduce the cost of management of acute scrotum.

Pediatr Radiol. 2005 Mar 11; [Epub ahead of print]

Wednesday, March 16, 2005

IMAGE QUIZ



A T-2 weighted MR image-Axial section brain

An unique opportunity to win my book "Review Of Radiology".All you have to do is diagnose this case post your answers as comments here and send your full name,current occupation and postal address to sumerdoc-AT-yahoo-DOT-com.

NOTE-In case of many correct entries the prize would be given by a lucky draw.

ANSWER-CLOSED LIP SCHIZENCEPHALY WITH HETEROTOPIC GRAY MATTER

Schizencephaly is one of the migrational disorders of brain, which include lissencephaly, pachygyria, heterotopia, and polymicrogyria.it is characterized by a gray matter lined cleft that extends from the ependymal surface of the brain through the white matter to the pia.
Two types are recognized: type I, or closed lip schizencephaly, in which the cleft walls are in apposition, and type II, or open lip schizencephaly, in which the walls are separated. In either instance the cleft is lined by heterotopic gray matter. The clefts can be unilateral or bilateral, symmetric or asymmetric.
Bilateral clefts have a worse prognosis for development, with seizures present in the majority. Patients may present with hemiparesis (more likely in unilateral forms) or tetraparesis (more likely in bilateral forms). Mental retardation and seizures are other common presentations, being more severe in bilateral clefts.
CT scans of closed lip schizencephaly may show only a slight outpouching, or "nipple" at the ependymal surface of the cleft. The full thickness cleft or the pial-ependymal seam may be difficult to detect on CT scans. Open lip schizencephaly has a larger, more apparent gray matter lined CSF cleft. The majority of patients have bilateral clefts, most of them roughly symmetrical in location and more likely open (type II) than closed (type I) the presence of heterotopic gray matter is considered pathognomic for schizencephaly, distinguishing it from an acquired condition.
Schizencephaly was earlier considered a rare anomaly but now with advent of axial imaging (CT and MRI) this condition is more frequently recognized.

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Tuesday, March 15, 2005

Grand Rounds XXV are up

Grand rounds 25 are up... it goes on like this-
As a child of television, I had to wonder what Grand Rounds would look like if it were TV, presented by a TV critic from a magazine known for its somewhat snarky TV reviews...

Check out Respectful Insolence (a.k.a. "Orac Knows")

Monday, March 14, 2005


Alveolar pulmonary edema showing the classical bat wing appearance, seen as perihilar fluffy opacities.
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Friday, March 11, 2005

Application of PET and PEt/CT imaging for cancer screening

Chen YK, Ding HJ, Su CT, Shen YY, Chen LK, Liao AC, Hung TZ, Hu FL, Kao CH

The aim of this study was to evaluate the potential application of 18-fluorodeoxyglucose positron emission tomography (FDG PET) and PET/CT for cancer screening in asymptomatic individuals. The subjects consisted of 3631 physical check-up examinees (1947 men, 1684 women; mean age +/- SD, 52.1 +/- 8.2 y) with non-specific medical histories. Whole-body FDG PET (or PET/CT), ultrasound and tumor markers were performed on all patients. Focal hypermetabolic areas with intensities equal to or exceeding the level of FDG uptake in the brain were considered abnormal and interpreted as neoplasia. Follow-up periods were longer than one year. Among the 3631 FDG PET (including 1687 PET/CT), ultrasound and tumor markers examinations, malignant tumors were discovered in 47 examinees (1.29%). PET findings were true-positive in 38 of the 47 cancers (80.9%). In addition, 32 of the 47 cancers were screened with the PET/CT scan. PET detected cancer lesions in 28 of the 32 examinees. However, the CT detected cancer lesions in only 15 out of 32 examinees. The sensitivity of FDG PET in the detection of a wide variety of cancers is high. Most cancer can be detected with FDG PET at a resectable stage. CT of the PET/CT for localization and characteristics of the lesion showed an increased specificity of the PET scan. The use of ultrasound and tumor markers may complement the PET scan in cancer screening for hepatic and urologic neoplasms.
Anticancer Res. 2004 Nov-Dec;24(6):4103-8

Wednesday, March 09, 2005

King Tut's CT scan rules out violent death

But test results provide little insight into how he died

Image hosted by Photobucket.com

King Tut wasn't murdered by a blow to the head, nor was his chest crushed in an accident. But after ruling out those long-time theories, the most revealing tests ever performed on the boy pharaoh's mummy didn't solve the mystery of how he died.
The results of the high-tech CT scan released yesterday raised one new possibility: They suggested that just days before his death, Tutankhamen might have badly broken his left thigh, puncturing the skin -- an injury that could have caused a dangerous infection.
But not everyone on the Egyptian-led team that pored over 1,700 CT images of Tut's body taken two months ago agreed with that theory. Some said the fracture could have occurred from mishandling when the mummy was discovered in 1922 in Luxor's Valley of the Kings.
Zahi Hawass, head of Egypt's Supreme Council of Antiquities, said the study allowed him to rule out violent death, but left him with no idea how Tut died. He said further tests will try to determine whether Tut died from natural causes, or perhaps was poisoned, but he stressed that it is unlikely they will find an answer.
Still, the CT results provided the most revealing insight yet into the life of ancient Egypt's most famous king, who ruled 3,300 years ago.
Tutankhamen was a well-fed, healthy, yet slightly built 19-year-old, standing 5 feet 6 inches tall at the time of his death, the test suggests. It was the first time his age has been established.
He had the typical overbite characteristic of other kings from his family and a slight cleft palate, which did not cause a cleft lip or other facial deformities. He also had large incisor teeth and his lower teeth were slightly misaligned.
While much interest has surrounded Tut's life, most attention has focused on how he died. X-rays taken in 1968 by Liverpool University anatomists found bone fragments inside Tut's skull, suggesting he might have been slain by being hit on the head.
But Mr. Hawass said the CT scan, the first ever performed on an ancient Egyptian king, ruled that out.
"The team found no evidence for a blow to the back of the head, and no other indication of foul play," he said.
He suggested that the fragments came from royal funerary workers who drilled a hole into the skull to let embalmers pour resins and other fluids in to prepare the body for mummification.
Some on the CT-scan team, which included two Italian experts and one from Switzerland, speculated that damage to the skull and upper neck might have been caused by the archaeological team led by Briton Howard Carter when they removed the pharaoh's famous golden mask after discovering his tomb.
Mr. Hawass said the team discounted a theory that the absence of Tut's sternum and most of his front ribs indicated a traumatic death.
"They also found it extremely unlikely that he suffered an accident in which he crushed his chest," he said, adding that such an injury would have caused damage elsewhere in the body, such as the spine, and the team saw none.
Mr. Hawass said he had no firm idea of how Tut died. But he offered two theories.
"He may have died from natural causes or was poisoned. We are going to look at his viscera to see if his organs show any signs, but it is virtually impossible to prove how he died," he said, giving no details on more tests or when they would be performed.
Mr. Hawass said Tut's death, around 1323 B.C., was surprising considering he was only 19, appeared to be healthy and suffered no infectious diseases or major childhood malnutrition.
"The mystery of his death will continue, but the case over whether he was [violently] murdered is closed," he said.
The CT scan, during which Tut's leather-like mummy was briefly removed from its tomb and placed into the scanner, did not address questions about Tut's precise royal lineage. It is unclear whether he was the son or a half brother of Akhenaten, the "heretic" pharaoh who introduced a revolutionary form of monotheism to ancient Egypt and was the son of Amenhotep III.
Mr. Hawass reiterated his refusal to allow DNA testing on Tut's remains, saying the science has a 40-per-cent chance for error when used on mummies.
"I believe these results will close the case of Tutankhamen, and the king will not need to be examined again," he said. "We cannot go again and open this mummy at all -- King Tut will rest forever."

http://www.theglobeandmail.com

Monday, March 07, 2005

Safety concerns of 3-Tesla MR scanners


Safety Considerations of 3T MR Scanners
Obviously, the safety issues involve the stronger magnetic field of the 3T system. The most conspicuous concern is the static magnetic field strength and the so-called projectile effect.
True, some guidelines for the MR environment remain the same with the stronger magnets. “Guidelines for general behavior in the MR environment, as far as watching out for strong static fields, will be the same for new systems and systems currently being used. This is especially true for the projectile effect, where ferromagnetic objects close to the static magnetic field can become dangerous projectiles that could injure or kill anyone between the object and the magnet. A 1.5T magnet has 30,000 times the strength of the earth’s magnetic field, while a 3T magnet has the force of 60,000 times the strength. When you reach forces of that level, it’s difficult to draw a line marking the point at which an object becomes a harmful projectile. How much more lethal would an unsecured oxygen tank become in the presence of a 3T system than near a 1.5T system?

Magnetic Field Effects
The most considerable concerns involve the effect of the magnetic field on medical devices and implants. Some medical devices are safe and compatible at 1.5 but not at 3T. A metallic device with weak ferromagnetic qualities in relation to a 1.5 system may experience significant magnetic field interaction at 3T.
Problems presented by 3T for metallic implants include translational attraction and torque. Translational attraction is essentially the projectile effect, when an object moves sideways toward a magnet. By comparison, torque, as it relates to MRI, refers to the shifting or twisting of ferromagnetic medical devices and implants inside the patient’s body. The movement is caused by the static magnetic field and can cause discomfort or injury if an implant is displaced. It can even cause death if the movement involves a life-sustaining device. Most reported cases of MR-related injuries and the few fatalities that have occurred have apparently been the result of failure to follow safety guidelines or of use of inappropriate or outdated information related to the safety aspects of biomedical implants and devices. To prevent accidents in the MR environment, therefore, it is necessary to revise information on biologic effects and safety according to changes that have occurred in MR technology and with regard to current guidelines for biomedical implants and devices.
In the study, which was published in the March 2003 issue of the American Journal of Neuroradiology (“Aneurysm Clips: Evaluation of Magnetic Field Interactions and Translational Attraction by Use of ‘Long-Bore’ and ‘Short-Bore’ 3.0-T MR Imaging Systems,” [Shellock, Jean A. Tkach, Paul M. Ruggieri, Thomas J. Masaryk, and Peter A. Rasmussen]), the researchers evaluated magnetic field interactions for 32 aneurysm clips in association with exposure to “long-bore” and “short-bore” 3T MR systems.Each clip was quantitatively assessed for translational attraction and qualitatively evaluated for torque. The researchers found that 17 of the 32 aneurysm clips showed positive magnetic field interactions. Specifically, 15 aneurysm clips made from commercially pure titanium and titanium alloy displayed no translational attraction, while 17 clips made from stainless steel alloy, Phynox, and Elgiloy displayed positive deflection angles. According to the researchers, the 32 different aneurysm clips passed the deflection angle test by using the long- and short-bore 3T MRI systems, which indicated that they are safe for patients and other persons in MR environments. However, the authors write, only clips made from the titanium and titanium alloy are entirely safe for patients undergoing MR imaging procedures because of the total lack of magnetic field interactions. The remaining clips require characterization of magnetic interactions.

Greater Heat Potential
Other crucial elements of safety are radiofrequency (RF), heat, and the specific absorption rate. RF energy pulses are used in every MR system to generate the signal measured during each scan. The absorption of RF power into the body causes heating of the tissue. Unregulated absorption can lead to injury.

Sunday, March 06, 2005

Journal Club-High-resolution sonography of the rib: can fracture and metastasis be differentiated?

Paik SH, Chung MJ, Park JS, Goo JM, Im JG.Department of Radiology, Soonchunhyang University, Bucheon Hospital, Gyeonggido, Korea.

OBJECTIVE: Our aim was to evaluate whether high-resolution sonography can provide additional information concerning rib lesions compared with radiography or bone scintigraphy.
MATERIALS AND METHODS: Fifty-eight patients with high-uptake rib lesions seen on bone scintigraphy were selected. Radiography and rib high-resolution sonography were performed on these patients. High-resolution sonography was performed using a linear 5-12 MHz transducer. By means of clinical history, histopathologic examination, and follow-up observation, these patients were classified into rib fracture (n = 37), rib metastasis (n = 18), or unknown (n = 3) groups. High-resolution sonography images of the 55 proven cases were reviewed for the presence of five representative findings: cortical disruption, callus formation, cortical deformity, mass, or bone destruction. The frequencies of these findings were compared between the groups with fracture and metastasis.
RESULTS: Rib lesions were matched by bone scintigraphy and high-resolution sonography in 53 (96%) of 55 patients and by bone scintigraphy and plain radiography in 23 (42%) of 55 patients. High-resolution sonography revealed 17 (94%) of 18 patients with metastasis and 36 (97%) of 37 patients with rib fractures. Metastatic lesions were seen as mass formation (n = 13) and irregular bone destruction (n = 7) on high-resolution sonography. Fracture was seen as cortical disruption with or without hematoma (n = 17), callus formation (n = 9), or cortical deformity, such as angling or stepping (n = 12).
CONCLUSION: High-resolution sonography of the ribs is a useful method of characterizing rib lesions in patients who have hot-uptake lesions on bone scintigraphy.

AJR Am J Roentgenol. 2005 Mar;184(3):969-74

Wednesday, March 02, 2005

Bone Age assessment with ultrasound device.

Assessment of skeletal age at the wrist in children with a new ultrasound device.
Mentzel HJ, Vilser C, Eulenstein M, Schwartz T, Vogt S, Bottcher J, Yaniv I, Tsoref L, Kauf E, Kaiser WA.

Background: Determination of skeletal development in children is important. The most common method of evaluation uses the standards of Greulich and Pyle (G&P) to assess the left hand radiograph. Numerous assessments may be made during follow-up.
Objective: The aim of our study was to compare the accuracy of a new sonographic method with the standard radiographic method. Materials and methods: Seventy consecutive patients (age 6-17 years; 34 girls, 36 boys) underwent radiography of the left hand, followed by sonographic examination of the same hand using the BonAge system (Sunlight Medical Ltd., Israel). This system evaluates the relationship between the velocity of sound passing thorough the distal radial and ulna epiphysis and growth, using gender- and ethnicity-based algorithms. One experienced paediatric radiologist analysed the radiograph and assigned bone age scores based on the G&P atlas for the whole left hand and for the distal radius alone. The radiologist was blinded to the chronological age (CA), height of the patient and the BonAge result. Correlation between BonAge and G&P was undertaken.
Results: In 65 patients, BonAge measurement could be performed successfully. In five patients, the scanning process was impossible using the ultrasound device. The r(2) (r is the Pearson correlation coefficient) of the BonAge ultrasound measurement and the G&P method was 0.82. The averaged accuracy (i.e. absolute difference in years between G&P reading and BonAge ultrasonic results) was calculated. Results were similar for boys and girls: 1.0+/-0.8 years for the whole left hand and 0.8+/-0.7 year for the distal radius. On average, the difference between BonAge and CA is the same as the difference between G&P and CA, i.e. 1.4 years.
Conclusions: The BonAge device demonstrates the ability of ultrasound to produce an accurate assessment of bone age. The results are highly correlated with skeletal age evaluated conventionally using the G&P method. Obvious advantages of the ultrasound device are objectivity, lack of ionizing radiation, and easy accessibility.

Pediatr Radiol. 2005 Feb 24; [Epub ahead of print]

Image Case


Antenatal diagnosis of esophageal atresia- a case showing polyhydramnios, absent stomach bubble and a pouch like dilatation of cervical esophagus.
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