Biomedical subjects
Publications and source records attributed to S Chopra.
The aim of this article is to present pictorially the spectrum of appearances of the appendix and appendicitis on CT. The images presented were selected from the database of our hospitals. The various appearances of the normal appendix on CT are shown. Appendicitis can be divided into four categories on the basis of CT findings. Examples of each category are shown.
We report a case of esophageal hemangioma presenting with dysphagia and odynophagia. To our knowledge, very few cases have been reported in the radiological literature.
Belgrade rats inherit microcytic, hypochromic anemia as an autosomal recessive trait (gene symbol b). Erythrocytes and tissue are iron deficient in the face of elevated TIBC (total iron binding capacity) and percent iron saturation; iron injections increased the number of erythrocytes but their appearance remained abnormal. We have investigated iron supplements to improve husbandry of b/b rats and to learn more about the underlying defect and its tissue distribution. Weekly i.m. (intramuscular) injections of iron-dextran (Imferon at 30 mg kg-1) improved the anemia but did not alter the red cell morphology. Certain diets also improved the health of b/b rats when compared to standard rat chows by the criteria of weight, survival to adulthood, hematology and reproduction. The critical nutritional factor turned out to be iron bioavailability, with ferrous iron added to the diet improving the health of Belgrade rats without affecting the underlying erythroid defect. Tissue iron measurements after dietary or parenteral supplementation confirmed the iron deficient status of untreated b/b rats and established that dietary ferrous iron partially relieved this deficiency, with injections leading to greater amounts of tissue iron. Serum iron and TIBC were also found to be elevated in untreated b/b rats, with dietary supplementation decreasing but not eliminating the elevation in TIBC. These studies indicate that iron supplements can improve the health of b/b rats without altering the underlying defect and also suggest that the mutation could alter iron uptake in the GI (gastrointestinal) tract.
To evaluate diagnostic computed tomographic (CT) angiograms of transjugular intrahepatic portosystemic shunts (TIPS), helical CT angiography was performed in 10 patients with (n = 7) or without (n = 3) shunt dysfunction. CT angiography was performed with 3-mm-thick sections, pitch of 1, 120 kV, and 180-220 mA, after injection of 150 mL nonionic contrast material at 5 mL/sec, with a 50-second scanning delay after initiation of injection. All patients underwent transjugular portography within 1 week after CT angiography. In all cases, CT angiography correctly showed the presence or absence of the abnormality. These preliminary data suggest that CT angiography can provide diagnostic images of normal and abnormal TIPS.
OBJECTIVE: This study was done to determine if the detection of pericolic lymph nodes on CT scans could be used to differentiate cancer of the colon from diverticulitis. MATERIALS AND METHODS: We retrospectively evaluated 58 CT scans from 57 patients with proven diverticulitis or cancer of the colon. The CT scans were evaluated by five board-certified radiologists who were unaware of the proven diagnosis. Consensus opinions regarding the presence and size of pericolic lymph nodes were recorded. These data were correlated with the proven diagnoses to determine the correlation between the observed findings and the type of colonic abnormality. Fisher's exact test was used to determine statistical significance. RESULTS: Lymph nodes were seen in 22 (71%) of 31 cases of colonic cancer and in four (15%) of 27 cases of diverticulitis. The lymph nodes were 0.5-2.5 cm in short-axis diameter. We saw no difference in node size for patients with colonic cancer versus patients with diverticulitis. The nodes were most commonly located along the blood vessels in the mesenteric fat. Statistical analysis showed a significant difference (p < .001) in the frequency but not in the size of nodes between the two groups of patients. The detection of nodes resulted in a diagnostic sensitivity and specificity for colonic cancer of 71% and 85%, respectively. CONCLUSION: Pericolic lymph nodes are seen much more frequently in patients with colonic cancer than in patients with diverticulitis. The detection of pericolic lymph nodes in patients suspected of having diverticulitis should raise the suspicion of underlying colonic cancer that should, in turn, prompt additional evaluation.
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UNLABELLED: Aim to describe the mammographic and ultrasonographic features of pure mucinous breast cancer. PATIENTS AND METHODS: The mammographic features of 15 patients and ultrasonographic features of seven patients with pure mucinous breast cancer were reviewed retrospectively by three experienced breast radiologists. RESULTS: The commonest mammographic appearance was of a poorly defined (86%) lobulated (71%) mass which could contain calcification (14%). A well defined mass (14%) and suspicious calcifications without a mass (7%) were also seen. Ultrasound showed a mass lesion in all seven cases which was either hypoechoic (86%) or mixed echogenicity (14%); 86% had a heterogeneous internal echo pattern; 71% showed distal enhancement while none showed distal attenuation. CONCLUSION: The imaging features of pure mucinous cancer are different from more common types of breast carcinoma. It is possible to misinterpret the appearances of this slow growing tumour as a benign lesion due to rarity of speculation on mammography and distal attenuation on ultrasonography. Most cases do, however, show other features suggesting malignancy.
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Thyroid cancer is treated by thyroidectomy followed by radioiodine ablation of the residual active tissue in the thyroid bed. Completeness of ablation can be assessed from neck images of whole-body 131I scans by visual estimation or quantitative analysis By visual assessment, ablation can be considered complete if there is no uptake in the neck or the uptake is empirically considered too small. By quantification, ablation is considered complete if neck uptake is < 1%. Further radioiodine therapy is considered necessary only if neck uptake exceeds 1% of the administered dose. Both visual assessment and quantification of thyroid bed uptake were applied to 46 scans after diagnostic or therapeutic doses of 131I had been administered to 25 patients who were being followed up for follicular or papillary carcinoma of the thyroid. The results were compared to assess the effect of either method on determining the need for a further ablative dose of 131I. Visual assessment overestimated thyroid bed uptake in 10 of 46 (22%) of the scans. Bearing in mind the unpleasantness of radioiodine ablation and the potential for bone marrow toxicity, it is recommended that quantification of neck uptake should be routinely performed as a guide to completeness of ablation and to determine the need for a therapeutic dose of the isotope. This should help to avoid unnecessary radioiodine treatment in patients with thyroid cancer.