Thursday, March 20, 2008

Radiology Grand Rounds XXII

Here is a case of Spinal ependymoma recuurence for the Radiology Grand Rounds submitted by Dr Sumer Sethi of Teleradiology Providers. Concept and Archive of the Radiology Grand Rounds is available at- Radiology Grand Rounds.

Pathology-Ependymomas are believed to account for 60% of all primary neoplasms of the spinal cord and filum terminale. Intraspinal ependymomas are most easily grouped into 3 classes: intramedullary lesions, myxopapillary ependymomas, and metastases from an intracranial origin. Intraspinal ependymomas are believed to arise from the ependymal cells lining the central canal, from the ventriculus terminalis of the conus, from within the filum terminale, or from cerebrospinal fluid (CSF) dissemination. xopapillary ependymomas arise almost exclusively in the region of the conus and filum terminale. They account for as many as 90% of tumors in the conus.

MRI-On T1-weighted images, ependymomas generally appear isointense relative to the normal cord, hyperintense relative to the normal cord on T2 weighted images. Ependymomas are and intensely enhancing with the administration of a gadolinium-based contrast material.

Hope you enjoyed this edition of Radiology Grand Rounds submissions are requested for the next Radiology Grand Rounds posted every month last sunday. If you interested in hosting any of the future issues contact me at sumerdoc-AT-yahoo-DOT-com.

Case by-
Dr.Sumer K Sethi, MD
Consultant Radiologist ,VIMHANS and CEO-Teleradiology Providers

Wednesday, March 19, 2008

Response Evaluation Criteria in Solid Tumors

Methods of Measurement
CT and MRI are the best currently available and reproducible methods to measure target lesions selected for response assessment. Lesions on chest X-ray are acceptable as measurable lesions when they are clearly defined and surrounded by aerated lung. However, CT is preferable.
Baseline documentation of “Target” and “Non-Target” lesions
All measurable lesions up to a maximum of five lesions per organ and 10 lesions in total, representative of all involved organs should be identified as target lesions and recorded and measured at baseline. A sum of the longest diameter (LD) for all target lesions will be calculated and reported as the baseline sum LD. The baseline sum LD will be used as reference by which to characterize the objective tumor. • All other lesions (or sites of disease) should be identified as non-target lesions and should also be recorded at baseline. Measurements of these lesions are not required, but the presence or absence of each should be noted throughout follow-up.

Response Criteria
Complete Response(CR):
Disappearance of all target lesions
Partial Response (PR): At least a 30% decrease in the sum of the LD of target lesions, taking as reference the baseline sum LD
Progressive Disease (PD): At least a 20% increase in the sum of the LD of target lesions, taking as reference the smallest sum LD recorded since the treatment started or the appearance of one or more new lesions
Stable Disease (SD): Neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD, taking as reference the smallest sum LD since the treatment started


Saturday, March 15, 2008

Discoid Lateral Meniscus-MRI

Discoid lateral menisci is a common problem. The normal configuration of a meniscus is that of a matured crescent moon, whereas that of a discoid meniscus generally is a thickened, very early crescent moon. Children with discoid meniscus usually present with a snapping knee joint, this snapping increases the chance of tearing the lateral meniscus as seen in this case. MRI is the modality of choice to evaluate a discoid meniscus before surgery.

Teaching Points :

Discoid meniscus is fairley common in children on clinical examination to come with snapping sounds of the knees.Clinical examination shows a senstivity of 88 % v/s an MRI sensitivity of only 38 % in various series.

There are 3 varieties – complete, incomplete and wrisberg variant.

Normal lateral meniscus covers approximately 70 % of the tibial plateau as compared to 50 % in case of medial meniscus.

The most acurate Radiological criteria is  a ratio of minimal meniscal width to the maximal tibial width exceeding 20 %. The others include squaring of the lateral tibial border, presence of osteochondritis dessicans at times, widening of the lateral joint space on X-ray.

The relative MRI criteria include minimal meniscal width on coronal of more than 15 mm, ratio of sum of both lateral  horns to the meniscal diameter of more than 75 %, absence of menico-capsular attachment and coronary ligaments on MRI.Discoid meniscus by its biomechanics, is more susceptible for shearing forces leading to tears more often. Treatment varies from conservasion to complete meniscectomy

Case by-
Dr.Sumer K Sethi, MD
Consultant Radiologist ,VIMHANS
CEO-Teleradiology Providers
Editor-in-chief, The Internet Journal of Radiology
Director, DAMS (Delhi Academy of Medical Sciences)

Tuesday, March 11, 2008

HRCT-Ground Glass Opacity

"Ground-Glass Opacity-Ground glass opacification is seen as increased opacification of lung without obscuration of the bronchial and vascular markings. GGO can represent partially filled alveoli, active inflammation, or fine fibrosis below the resolution of CT images"
Causes - Alveolar proteinosis, Adult respiratory distress syndrome, Acute interstitial pneumonitis, Bronchiolitis obliterans oganizing pneumonia (BOOP),Desquamtive interstitial pneumonitis etc
Further reading---
AJR 2005; Miller WT, Shah RM. Isolated diffuse ground-glass opacity in thoracic CT: causes and clinical presentations. 184: 613-622

Tuesday, March 04, 2008

Radiology Mistakes on TV

How many of us radiologists notice this on TV and cinemas every now and then! A very interesting blog post by Mike Enriquez in Advanceweb Magazine wherin he says--"The number of times I have seen radiographs incorrectly placed on the view box in one of these shows is way too many. I mean, basic stuff that the show producers just can't seem to get right! Numerous PA chest images have been shown reversed! How about when AP Abdomen Flat Plate images are viewed upside down? And, then, there are the insults to technical quality! Ever notice how any time you are shown an AP skull image and the entire image receptor has been exposed? Not any signs of collimation or a R/L marker anywhere to be seen!"

Blog Archive