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Biomedical subjects

A N Shetty

Publications and source records attributed to A N Shetty.

23 records · Page 2Linked to original sources
PubMedDate not supplied

Pelvic endometriosis: MR imaging spectrum with laparoscopic correlation and diagnostic pitfalls.

Endometriosis is a common multifocal disease involving a number of anatomic sites in the pelvis. Although laparoscopy is the standard of reference for diagnosis, magnetic resonance (MR) imaging is a noninvasive method for evaluating areas inaccessible to laparoscopy. A large endometrioma (> or = 1 cm in diameter) appears as a homogeneously hyperintense mass on T1-weighted MR images and as a low-signal-intensity mass with areas of high signal intensity on T2-weighted images. A small endometrioma may be indicated when a pelvic mass less than 1 cm in diameter is hyperintense on T1-weighted images irrespective of its appearance on T2-weighted images. Endometriosis may also manifest as multiple, homogeneously hyperintense cysts on T1-weighted images. Involvement of the alimentary tract or bladder can appear as areas of high signal intensity. Although MR imaging is limited in its ability to depict small endometrial implants and adhesions, the advantages of MR imaging over laparoscopy include the ability to characterize endometriotic lesions and to evaluate extraperitoneal sites of involvement, contents of a pelvic mass, or lesions hidden by dense adhesions. The roles of the two modalities are therefore complementary. Knowledge of the variety of MR imaging appearances of endometriosis and organ involvement within the pelvis is important for guiding a subsequent laparoscopic examination.

Adult↗
PubMedDate not supplied

Contrast-enhanced MR angiography of the mesenteric circulation: a pictorial essay.

Outstanding results have been achieved with magnetic resonance (MR) angiography, which has become competitive with conventional angiography as a vascular imaging technique. With the advances in gradient technology and the capability of imaging vessels in a single breath hold, one can track an intravenous bolus of paramagnetic contrast agent and evaluate the entire mesenteric circulation. Use of a breath-hold technique obviates the problem of motion artifact. Use of targeted maximum-intensity projection images from the three-dimensional (3D) volume data allows evaluation of the vascular anatomy at different phases (arterial and venous) of contrast enhancement. MR angiography performed with a contrast-enhanced breath-hold fat-suppressed 3D technique allows visualization of the superior mesenteric vessels, celiac artery, and portal vein in healthy subjects. Pathologic conditions of the mesenteric vessels that can be identified with this technique include stenosis or occlusion of the superior mesenteric artery, celiac artery aneurysm, thrombosis of the superior mesenteric vein, portal hypertension with varices, and vascular invasion by pancreatic carcinoma.

Adult↗
PubMedDate not supplied

MR angiography of the thoracic aorta with an electrocardiographically triggered breath-hold contrast-enhanced sequence.

An electrocardiographically (ECG) triggered breath-hold contrast material-enhanced magnetic resonance (MR) angiography sequence has been developed for imaging the thoracic aorta. A three-dimensional (3D) gradient-echo sequence is used with a contrast material bolus. Forty-nine patients with various aortic abnormalities and five healthy volunteers underwent imaging with the sequence. All studies were performed in a single breath hold. ECG-triggered breath-hold contrast-enhanced MR angiography was tolerated in 48 of the 49 patients. The images demonstrated no respiratory motion artifacts and diminished pulsation artifacts. The cardiac chambers, aortic root, ascending and descending aorta, aortic arch, proximal arch vessels, and proximal coronary arteries were clearly demonstrated and not obscured by ghost artifacts. The 3D data set allowed excellent multiplanar reformation, permitting orthogonal or oblique views of the vascular anatomy. A variety of congenital and acquired abnormalities were clearly identified. When this sequence is used, it is important to evaluate both the maximum-intensity projection and source images. Delayed imaging should be performed to detect late filling. In conjunction with cine MR and T1-weighted spin-echo imaging, ECG-triggered breath-hold contrast-enhanced MR angiography should be considered the technique of choice for imaging the thoracic aorta.

Aorta, Thoracic↗
PubMedDate not supplied

A comparison of continuous infusion of vecuronium and atracurium in midline and paramedian laparotomies.

This was a study to compare continuous intravenous infusion of atracurium with continuous intravenous infusion of vecuronium for intraoperative muscle relaxation in 62 ASA I / II patients. Scheduled for laparotomies and pelvic surgeries under general anaesthesia. They were randomly allocated in two groups to receive either vecuronium infusion of 50 microg/kg/hour following a bolus dose of 0.1 microg/kg, or atracurium infusion of 400 microg/kg/hour following a bolus dose of 0.5 microg/kg. The mean infusion dose of atracurium was 478 +/- 44.11 microg/kg/hour and that of vecuronium was 63.2 +/- 74 microg/kg/hour for adequate muscle relaxation. The depth of neuromuscular blockade was monitored by using peripheral nerve stimulator so that only one twitch of train of four was present, resistance to ventilation, surgical relaxation and haemodynamic changes. Vecuronium infusions produced more haemodynamic stability than atracurium infusions. Vecuronium produced lesser change in systolic blood pressure (mean change of 3. 46 +/- 3.33%) from baseline values as compared to atracurium (mean change of 5.81 +/- 3.73%) from baseline values ( p < 0.01) which was statistically significant. The difference in mean pulse rate change from baseline value in the atracurium group (4.78 +/- 2.745%) was less than that in the vecuronium group (5.99 +/- 2.67%), which was not statistically significant. Spontaneous recovery was faster with vecuronium (540.94 +/- 76.46 seconds) as compared to atracurium (596. 33 +/- 72.48 seconds). 84.4% of patients who received vecuronium fell within good to very good category of muscle relaxation as compared to 63.3% in atracurium group. There were no cost benefits when either agents were used in infusion form.

Adolescent↗