Tuesday, September 27, 2011

Spinal Epidural Lymphoma- Review Article

Primary spinal epidural lymphoma (PSEL) is a subset of lymphomas, where there are no other recognizable sites
of lymphomas at the time of diagnosis.  The incidence of this subset of lymphomas is much less. It, however, is increasingly diagnosed, due to the increased use of more sensitive imaging modalities. 

Review article is now published with me as one of the contributors: Cugati G, Singh M, Pande A, Ramamurthi R, Balasubramanyam M, Sethi SK, et al. Primary spinal epidural lymphomas. J Craniovert Jun Spine 2011;2:3-11. Full free text is available.

Monday, September 26, 2011

Acute Cerebellitis-is it infectious or post infectious?

12 yr old boy had febrile episode of 5 days before developing seizures, and ataxia with altered sensorium and shows  on MRI,  an ill defined possibly” C “shaped , subtly enhancing  fluid signal intensity on all pulse sequences , of predominantly white matter regions  of posterior fossa, with more of vasogenic  rather than cytotoxic oedema ,  mass effect on 4th ventricle, leading to  proximal hydrocephalus  and no bleed- picture suggestive of post infectious BRPINDs (Benign  Regressive  Post   Infectious Neurological  Disorders)

Teaching points by Dr MGK Murthy.  Contributors- Mr Hamid and  Mr Gupta

1.      Infectious edema  can be diagnosed by (a) short duration ,(b) gray matter as site of involvement,(c) decreased mental status  and (d) abnormal CSF, with post infectious exhibiting  opposites of these characteristics
2.      “C” shape is apparently on account of myelinating axons separating the areas of edema
3.      Post infectious demyelinating oedema is possible
4.      BRPINDs  usually exhibit good prognosis with no residual  disabilities
5.      These can be of ADEM variety where brain and cord are involved, or neuromyelitis optica where only optic nerves and cord are involved or only cerebellar variety (as in this case)
6.      MRI  is usually diagnostic  with CSF playing complementary role
7.      BRPINDs could be caused by bacterial/viral/vaccination (MMR)/drugs(arsenic, gold and sulfas etc)/Miscellaneous(herbal extracts etc)

Renal Sinus Tumor-MR urography

An adult male underwent USG check for left loin pain  with no hematuria. USG suggested a mixed echogenic mass for which enhanced CT showed heterogenous mildy enhancing mass in the renal sinus on left , possibly transitional cell carcinoma  with distorted collecting systems. MR urography has been advised in the light of this. It shows  a relatively  well defined complex mass lesion in the renal sinus location with stretched calyces and pelvis as such with no hydronephrosis or MR demonstrable calcification. It displays  relative bright signal on T1 and intermediate on T2 with heterogenous suppression on fat suppression. Inview of the above , mesenchymal origin  tumour lesions like fibroma are possible. Rest of  the  urography is normal

Teaching points by Dr MGK Murthy. Contributors Dr Krishna Mohan and Mr Laxman

1.Renal sinus  is perinephric space extension to deep recess on medial border of kidney
2. Has major artery/vein, major/minor collecting systems, adipose tissue/lymphatics/nerves of autonomic nervous system/varying degrees of fibrous tissue
3.Lesions are  defined as non tumorous  {lipomatosis/cysts/vascular orgin including aneurysms/fluid collections including urinomas  or extravasations}
And tumourous {renal pelvis(TCC)/mesenchymal origin(lipoma/fibroma etc)/renal parenchyma or retroperitoneal tumours projecting in to the region}
4.Parapelvic is usually referred to as alongside and peripelvic is defined as diffuse and all around the pelvis in terminology
5.USG is inadequate in tumors conditions and urography only shows sequelae
6.Coronal CT on MDCT technology is the ideal modality of choice with MRI including MR Urography playing a decisive role in  conflicting findings
7. 90%of renal pelvis tumors are Transitional cell carcinomas with 10% particularly in presence of calculus –squamous carcinoma and haematuria is  MUST
8.Mesenchymal  tumors include fibroma, hemangioma, leiomyoma, and angiomyolipoma and radiological  clue would be calyces stretching  with/ without  hydronephrosis

Friday, September 23, 2011

Multislice CT-The Modern Leonardo Da Vinci

Leonardo Da Vinci- drew many studies of the human skeleton and its parts, as well as muscles and sinews. He studied the mechanical functions of the skeleton and the muscular forces that are applied to it in a manner that prefigured the modern science of biomechanics.He drew the heart and vascular system, the sex organs and other internal organs, making one of the first scientific drawings of a fetus in utero. Look at this image taken from wikipedia and is a drawing of heart by Leonardo Da vinci and see how closely it resembles the Cardiac CT image, that is why, it may be appropiate to label multislice CT as modern Leonardo..

Tracheal Diverticulum-CT

67 year old smoker with shortness of breath shows: right paratracheal focal air cyst of approximately 3.2 cms length and 1 cm lumen with thin communication to the posterior tracheal wall with no cartilaginous rings. It suggests the uncommon tracheal diverticulum.

Teaching points by Dr MGK Murthy:

Paratracheal air cyst is a nonspecific term used for collection of air parallel to the trachea. Usually it occurs on the right in view of left side being occupied by esophagus.

Absense of alveoli excludes apical hernia or paraseptal bullae or blebs.

Barium swallow / oral contrast  would differentiate Zenker's diverticulum or pharyngocele. Extension from directly below the vocal cords would go in favour of laryngocele.

Presence of azygos fissure would occur along with azygos lobe.

Tracheal diverticulum can be 

a). congenital – possibly represents vestigial supernumerary  lung buds or aborted abnormal buds.
Lined by cartilages.
Small and narrow mouthed.

b). Acquired – Usually in smokers or chronic cough or expiratory obstructive air way diseases.
Majority at D2 level.
Size can varying.
Expand during forced expiration and decreased in inspiration.
Usually due to weakness in the posterior wall with pulmonary functions abnormality.
Lined by respiratory epithileum.

Mounier – Kuhn syndrome consists of multiple tracheal diverticula with marked dilatation of trachea and main bronchi with bronchiectasis and repeated lower respiratory tract infections.

Wednesday, September 21, 2011

3Tesla MRI- Article Published

Our article on 3 Tesla MRI in Neuroimaging was recently published in Imaging & Diagnostics magazine issue 3,  we are sharing the   link to the online version for our readers and peers here.

3Tesla MRI in Neuroimaging.

Tuesday, September 20, 2011

In House Radiologist versus Outsourcing

This eternal debate continues with Sep 2011 issue of Journal of the American College of Radiology, where authors talk of  value-added services by having radiologists in house: (1) patient safety, (2) quality of the images, (3) quality of the interpretations, (4) service to patients and referring physicians, (5) cost containment, and (6) helping build the hospital's business. 

 However, according to me, a mixed approach where in we have teleradiology complementing the inhouse team, by means of 1) vacation coverage,  2) added expertise for example we help one of our centres in cardiac CT and other in MSK MRI, 3) Peer Review , 4 ) Second opinions.

Placental Insufficiency & Diffusion-weighted Imaging

 Study published in December 2010 Radiology, 257, 810-819, suggests that placental dysfunction associated with growth restriction is associated with restricted diffusion and reduced ADC. Looks like another promising application of DWI in future.

Monday, September 19, 2011

Never Conclude Fractures on One Projection

The good old Radiographic principle revisited
Never conclude on one projection. Example by Dr MGK Murthy.

Patient with history of  fall
Frontal oblique apparently comfortable with soft tissue shadow  in the vicinity  of  fifth digit with  mild curvature of metacarpalin the region

Lo  behold!!

Do another projection and we have stippled pieces of bone in the vicinity of proximal row carpus possibly emanating from triquetral. Triquetral fractures are best seen on lateral radiograph and are due to  forced hyper flexion injuries  due to attachment of  Radiocarpal ligament

Remember acceptable  criterion for True lateral wrist
Radiograph for scapho –piso- capitate alignment -Ventral cortex of pisiform shows between ventral cortices of distal pole of scaphoid and head of capitate. Our X ray fits in to acceptable criterion (but not excellent) as pisiform is over the scaphoid almost completely

What do we do?
 We go for  MRI (to exclude extensor carpi ulnaris tendon and other soft tissue injuries apart from marrow edema delineation) and if necessary for MDCT after that

Whoever said Plain X rays are simple  with digital  technology

Radiology and Gulf war-Hippocampal Perfusion Dysfunction

Now in the latest issue of Radiology published online Sept. 13, researchers have found Gulf War veterans with specific syndromes, abnormal hippocampal blood flow persists, and in some cases worsens, 11 years after initial testing. War surely has long lasting effects.

Saturday, September 17, 2011

Opercular Syndrome-MRI

10 year old male child comes with history of seizures with no significant birth history. MRI shows bilateral symmetrical FLAIR hyperintensities which are heterogeneous involving opercular regions with no restriced diffusion or blooming on SWI suggesting bilateral opercular syndrome.

Teaching points by Dr MGK Murthy :

Also called facio-labio-pharyngo-glosso-laryngeal and brachial paralysis or cortical variety of pseudo-bulbar-palsy or Foix – Chavany – Marie syndrome.

Five clinical types:
(a) the classical and most common form associated with cerebrovascular disease.
(b) a subacute form caused by CNS infections.
(c) a developmental form most often related to neuronal migration disorders.
(d) a reversible form in children with epilepsy.
(e) a rare type associated with neurodegenerative disorders.

Can be congenital or acquired, intermitant or persistent.

Characterised by a loss of voluntary control of facial, lingual, pharyngeal and masticatory muscles in the presence of preserved reflexive and automatic functions of the same muscles.

Thursday, September 15, 2011

Cardiac CT/PET-will we take back cardiac imaging ultimately?

According to September 2011 RadioGraphics, 31, 1239-1254, edition where the authors predict the utility for cardiac PET/CT especially for coronary artery disease.  According to them, Hybrid PET–computed tomography scanners allow functional evaluation of myocardial perfusion combined with anatomic characterization of the epicardial coronary arteries, thereby offering great potential for both diagnosis and management.  Cardiac PET can be performed with an increasing variety of cyclotron- and generator-produced radiotracers

Wednesday, September 14, 2011

Making your Radiology Practice BIG

Key question

Brand creation versus Incentive based strategies.

Why is radiology business not such an easy business to create BRAND VALUE for consumers.
Image source-Wikipedia.

-          Patients are consumers but not the deciding factor in RADIOLOGY. Referring physician decides.
-          His decision is not only based on EXPERTISE but also on incentive and personal relationships.
-          Still Pathology labs have done it in past, is it possible in Radiology?
-          Teleradiology is bound to become the basis of common brand creation in radiology centre chain
-          Sonographers will be required as getting radiologists to do the ultrasounds is getting tougher by the day. Sonographers should do the USG and radiologist should interpret the images.
-          Some corporate chains are already working on acquiring existing centres and creating common platform.
-          There is definite role for entrepreneurs in this field in times to come for sure. Running an ultrasound centre in your locality is NOT entrepreneurship. What are your thoughts on this topic? All comments are welcome.

Dengue Hemorrhagic Fever-MRI

32 yr adult with clinical and serology positive Dengue fever with acute encephalopathy with low platelet  counts   shows on CEMRI, multiple hemorrhagic   focal lesions in supra and infratentorial locations with relative sparing of basal ganglia and brainstem and varying degrees of  restriction and enhancement ,   possibly explained by different ages of bleed and  therefore varying  degrees  of breakdown of blood brain barrier

Questions in the case
1. Thalami spared?---   variations are reported
2. Enhancement is varied  in different lesions? possibly  related to  different ages of  bleed
3. Meninges normal--  Imaging  is not good  enough for meningitis
4. Cord is normal?--- encephalomyelitis is only  known to occur in some
5. Is comorbidity possible with some other infections?—certainly possible, but since serology and CSF are negative, less likely

Teaching points  for Radiologist  by Dr MGK Murthy. Images by Mr Hariom and Mr Venkat.
·         Dengue fever occurs in about 100 countries ,and is caused by RNA virus of Flavivirdae family
·          Non-neurotropic nature of the virus is now questioned with some  growing from CSF
·         Neurology involvement can be encephalitis (direct virus effects) or more common encephalopathy (usually metabolic, hypotension or haemorrhage  related findings)
·         CSF serology an virus culture are considered as gold standard
·         MRI plays crucial role in altered sensorium patients to  exclude  other causes  as well  show focal lesions apart from  severity and nature
·         Viral encephalitides have predilection for certain sites as below :
HSV: Frontal, Temporal lobes
Japanese Encephalaitis: Thalamus, basal ganglia, cerebellum, brainstem
West Nile fever: Deep grey matter, mesial temporal lobe, cerebellum, brainstem. Difficult to differentiate from JE on imaging alone
Rabies: Hippocampi, basal ganglia, brainstem , temporal lobes.
Chikungunya: cingulated gyrus, Limbic system
Nipah: multiple white matter lesions.

Monday, September 12, 2011

Cardiac decompensation-CXR

Elderly person with shortness of breath what is the finding?

There is big heart and generally ill-defined lung fields. On closer examination,  we notice, upper lobar vessels are around 3mm(normal maximum of 2mm) called cephalization has occurred. There are few areas of peribronchial cuffing i.e. there is interstitial fluid accumulated around the bronchi  making them look like doughnuts . Both perihilar regions are hazy and ill-defined suggesting fluid. The appearance  is  classical of  cardiac decompensation.

Teaching points by Dr MGK Murthy
·         Left atrial pressure measure is quite represented by X ray appearance. Normal being 5-10 mm Hg, cephalization(10-15),Kerley B lines (15-20),interstitial edema(20-25), an alveolar edema(>25mm Hg)
·         Kerley B lines are 1-2 cms long horizontal bases  lines  and are perpendicular to pleural surface
·         Pulmonary oedema usually clears in about 3days or less. Clearance is usually from periphery to center(because of  emptying effect of breathing and movement )
·         Unilateral oedema may be seen in dependent side if patient lies on one side overnight. Normal vessel to bronchus ratio is upper lobes(0.85), at hila(1.0) and lower lobes (1.35).

Trachea on CXR-Patient with Stridor

What are the findings in elderly male with  history of  wheezing?
Tracheal lumen despite malrotation and flexion of the neck looks abnormal focally in thoracic segment. The others include curvilinear calcification at the left heart border with no significant cardiomegaly along with left costopleural opacity

How do we explain and what is the important finding?
It is difficult to pinpoint extent of severity of individual findings in this patient at this time. However as the  patient has reported for wheezing with possible expiratory stridor, I would suggest we concentrate on Trachea and ask for direct/ indirect tracheoscopy , fluoroscopy to see post wall collapse or CT chest or simply good lateral view and follow up  x- rays ( if clinical situation permits)

Teaching points by Dr MGK Murthy, Resident-Professor Series.
·         Trachea extends  from cricoid(C6) to carina with inferior end dynamic and changes with inspiration/expiration coming up to D6 at times
·         PA of Chest and true lateral with head hyperextended with high KVp(to get less of white bony thorax) are ideal. Unusual flexion of the neck specially in children produces buckled appearance (pseudomass )
·         Triad of  Anterior buckling of posterior tracheal wall, narrow AP dimension, and widened posterior membranous tracheal wall clinch tracheomalacia as diagnosis(fluoroscopy will help see unusual  expiratory collapse)
·          The other uncommon  causes are usually pappillomatosis, leiomyoma, schwannoma, paraganglioma, melanoma, carcinoma and sarcomas(1 true tracheal tumor for every 140 bronchogenic carcinomas estimated )
·         CT particularly in inspiration/ expiration is the imaging modality of choice

what about the heart and pleura in this case?
Incidental aneurysms in elderly age(this patient is 93 yrs old ) need echo correlation for evaluation and pleural thickening needs no follow up

Saturday, September 10, 2011

Possible Mycotic Pseudoaneurysm Superficial Temporal Artery-MDCT

Evidence of mild bulkiness of the right parotid gland along with multifocal vascular structures showing arterial phase enhancement in the substance of the parotid gland in relation to the course of the superficial temporal artery with vascular lesion lying anterior to the tragus. 

DifferentialsVascular lesions in this location in adult are a rare occurrence and this lesion however, likely represents vascular pathology with possible communication with superficial temporal branch of ECA, differential of such appearance although uncommon includes post mycotic pseudoaneurysms, may be sequale of parotitis. There is no history of trauma in this case. Haemangioma is less likely as they are relatively more common in younger age groups and show enhancement of focal area of a gland as a whole. 

Wednesday, September 07, 2011

Traumatic Lung Cyst-CT

This is a 16 year old male who developed hemoptysis following RTA. CT scan revealed subpleural alveolar opacification along with cystic lucency, which possibly represents contusion with post traumatic lung cyst. These traumatic lung cysts or lacerations usually not apparent at first because of surrounding pulmonary contusion. They are usually subpleural location under point of maximum impact.

Neck Lymphnode Levels for Radiologist

Whenever we are reporting a Head and Neck malignancy, radiologists should be aware of the following system of  levels which is universally understood by surgeons and pathologists.

Simplified numerical classification system

Group IA nodes are located in the submental space, between the anterior bellies of the digastric muscles.
Group IB (submandibular) nodes are found in the submandibular space
Groups II, III and IV are internal jugular nodes and they are divided into these three groups by two landmarks: the hyoid bone and the inferior border of the cricoid cartilage. Group II nodes are located above the hyoid cartilage Group III nodes are found between the hyoid bone and cricoid cartilage  and Group IV nodes are located below the cricoid cartilage
 Group V nodes are found in the posterior triangle Group V nodes can be identified on axial images posterior to the posterior margin of the sternocleidomastoid muscle.
Group VI nodes are anteriorly located: between the hyoid bone superiorly, the suprasternal notch inferiorly and between the carotid sheaths laterally.

Further reading and references:
Cervical lymphadenopathy: what radiologists need to know. Vincent Chong. Cancer Imaging. 2004; 4(2): 116–120.

Tuesday, September 06, 2011

Kohler's Disease-Plain Film

Köhler disease (also spelled "Kohler") is a rare bone disorder of the foot found in children between six and nine years of age. The disease typically affects boys, but it can also affect girls. It was first described in 1908 by Alban Köhler (1874–1947), a German radiologist.

    - self limiting avasulcar necrosis of the navicular;
    - navicular is subjected to repetitive compressive forces during weight t bearing which may be a risk factor for AVN, also, navicular is last bone in foot to ossify & delayed ossification appears to make the navicular more vulnerable to compressive damage.

Interesting to note- In February 2010 the Journal of the American Medical Association reported that the 19-year-old king Tutankhamun may well have died of complications from malaria combined with Kohler disease.

Foot X-ray-Interpretation Series

An adult with history of pain in the base of 2nd toe with history of trauma . Resident-Professor Series by Dr MGK Murthy.

 1.What is it?
 There is a bony spur emanating from the lateral margin  of 1st metatarsal base

2.Is it  related to history of  present trauma ?
No it is not likely to be related to  the present trauma. Bony spurs occur in the foot very commonly as a result of chronic repetitive trauma of subclinical threshold variety or  as result of acute fracture healing.

3. Is there any other abnormality?
 I am not comfortable with flattened head of  2nd MT – one should immediately consider freibergs infarction. The os cuboidale is giving the impression of calcaneo-cuboid bridging .

4. Is it ?
 No it is not likely as the symptoms are not in that region and there is no increased density

5. Then what is it?
 It should be considered as anatomical variation or subtle biomechanical forces of the patients habitus which has led to remodeling of   the region.

What is new for Radioloigsts on ACL?

 Intercondylar notch width on Xray in tunnel view   acts as good predictor of  susceptible population for Anterior cruciate ligament problems. In one study, normal for adult males was 0.206 ,and females 0.208. On followup those developed ACL subsequently  has significantly reduced notch width (males 0.178 and females 0.172)
Does that mean, smaller notch width will cause ACL tear?  No it means , the ACL  is more susceptible because of bio-mechanics. Submitted by Dr MGK Murthy.

Friday, September 02, 2011

Don’t believe Scaphoid unless you have seen it all

This case is a part of our resident-professor series, by Dr MGK Murthy.  This algorithm is not based on text books and is our own clinical experience.

Is this fracture?
No it looks like  calcification on other views

Now is this Fracture?
Yes it is fracture of tubercle though the other oblique is not suggestive

 Why is that?
 In the second case  there was anatomical snuffbox tenderness and  it is of utmost importance even in todays digital world

What do we suggest to clinician?
Dr Murthy recommends to all clinicians,
·         If X ray is abnormal and tenderness then it is fracture definite
·         If x ray is positive and no tenderness snuff box then think of old fracture or calcification particularly  stress related and degenerative, MRI would solve riddle
·         If tenderness is there and X-ray is normal, still believe tenderness and go for  MRI or nuclear scan
·         If no tenderness and  Xray is suspicious then do other side to see anatomical variations
·         If both are negative then look  for other causes of pain and MRI will help. 

Thursday, September 01, 2011

Developmental Hip Dysplasia-MRI

A 9 month male baby has been felt to have clinically abnormal left hip with possible developmental dysplasia on the frontal radiograph with nondetectable femoral head. MR shows normal left femoral capital epiphysis, with possible delayed ossification ( not seen on the X-ray ) with dislocated position taking it to the upper and the outer quadrants of the intersection of hilgenreiner's line and perkin's lines with disturbed shenton's line with abnormal acetabular angle with normal capsule, labrum, ligamentum teres, iliopsoas tendon with mild free fluid and no AVN. Case submitted by Dr MGK Murthy, Mr Abdul Hamid, and Mr Sahadev Gupta.

Teaching points :

-        Developmental dysplasia of the hip is to be avoided with routine clinical examination at birth.
-        USG is a preferred modality till 6 months of age, when the femoral head shadowing may start interfering with acetabulum image ( femoral head starts ossification between 2 to 8 months ).
-        X-ray is the preferred modality after that with frontal projection and if needed frog leg positions ( Hip in flexion with external rotation )
-        MR is good for identified capsule, labrum, cartilage, presence of AVN and effusion, iliopsoas tendon compression, thick ligamentum teres and pulvinar hypertrophy.
-        Hilgenreiners (HG) line is the horizontal line between two triradiate cartilages.
-        Perkins line is perpendicular to HG and represents outer acetabular margin.
-        Shentons line is an extension of medial femoral metaphysis along the inferior edge of superior pubic ramus.
-        Acetabular angle is normally less than 28 degrees (decreases with age), and is measured as between HG and a line joining superolateral and inferomedial acetabular margins.

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