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Biomedical subjects

S A Merchant

Publications and source records attributed to S A Merchant.

At least 19 recordsLinked to original sources
PubMed2005

Magnetic resonance urography (MRU) versus intravenous urography (IVU) in obstructive uropathy: a prospective study of 30 cases.

AIM: Intravenous Urography (IVU) as a diagnostic modality has limitations in patients of obstructive uropathy with impaired renal function. Our aim was to study the technique and diagnostic accuracy of Magnetic Resonance Urography (MRU) in obstructive uropathy and to correlate the findings with IVU. METHODOLOGY: Forty-eight patients, selected over a six-month period, based on mild to severe pelvicalyceal dilatation on screening ultrasonography, underwent an IVU; those having non-obstructive dilatation were excluded (18 patients). Thirty patients (age range 10 to 75 years) with definite obstructive dilatation underwent MRU. These were obtained using an open MRI unit (Siemens Magnetom Open Viva) with low-dose gadolinium-DTPA (0.01 mmol/kg body weight) using various MRI sequences. MRU studies were classified as 'excellent' or 'diagnostic' and data generated was compared with that of IVU. RESULTS: MRU studies were 'excellent' in twelve and 'diagnostic' in eighteen patients. Of the sixty pelvicalyceal systems (PCS) evaluated in thirty patients, there were thirty-seven calculi, nine pelvi-ureteric junction (PUJ) obstructions, six with impaired renal function, four malrotated kidneys and one each of horseshoe kidney, pancake kidney, pelvic mass (endometriomas), duplex moieties, ureterocele and vesico-ureteric reflux. MRU better depicted moderate-severe PCS dilatation, staghorn and urethral calculi, impaired renal function, extrinsic ureteric and PUJ obstruction. IVU better depicted small calculi and mild PCS dilatation. CONCLUSIONS: In these thirty patients of obstructive uropathy, low magnetic field, open MRI units and low-dose Gd-DTPA provided cost-effective MRU studies with excellent diagnostic utility. MRU scored over IVU in patients with moderate-severe dilatation, staghorn and urethral calculi, impaired renal function, extrinsic ureteric and PUJ obstruction.

Adolescent↗
PubMed2003

Role of multidetector CT virtual bronchoscopy in the evaluation of post-tracheostomy tracheal stenosis--a preliminary study.

AIM: To study the technique and utility of virtual bronchoscopy (virtual reality endobronchial simulation, VRES) as a tool to evaluate post-tracheostomy tracheal stenoses and to correlate the findings of virtual and invasive bronchoscopy and to follow-up treated lesions or those currently under treatment that were initially diagnosed with VRES. METHODOLOGY: This prospective study comprised nine patients in the age group 13 to 65 years presenting with breathlessness and stridor following one or multiple tracheostomies. They underwent plain CT using a multidetector CT (MDCT) scanner (Siemens Volume Zoom) using narrow (1 mm) collimation. These thin slice images were post-processed using an Irix-based workstation with a 'Fly-Through' endoscopy application. These patients also underwent a rigid (three patients) or fiberoptic (six patients) bronchoscopy. RESULTS: Of the nine patients that underwent VRES, five were found to have stenoses, three had obstructing granulation tissue, one had an obstructing membrane and one had synechiae. The invasive bronchoscopic findings supported the VRES diagnosis in all but one case of stenosis, one of granulation tissue and the case with synechiae. Membranes and synechiae were relatively difficult to diagnose without the corresponding axial and multiplanar images. VRES achieved a higher sensitivity, while invasive bronchoscopy a higher specificity. CONCLUSIONS: VRES proved to be comparable to invasive bronchoscopy in the depiction of post-tracheostomy tracheal stenoses, with a notable advantage in critical stenoses in that the airway distal to the stenosis could be assessed with VRES but not with invasive bronchoscopy. A preliminary VRES was found to be of assistance in the selection of patients for the more invasive therapeutic procedures such as laser ablation of granulation tissue and its follow-up.

Adolescent↗
PubMed1991

Ureteral obstruction in hydatid disease.

A case of ureteric obstruction in renal hydatid disease is reported. This unusual complication possibly occurred following surgery. To the best of our knowledge, this has not been previously reported.

Echinococcosis↗
PubMed1991

Ultrasound guided aspiration cytology--a valuable diagnostic aid.

Ultrasonography (US) remains underutilized as a guidance tool for performing fine needle aspiration cytology (FNAC) mainly because of a lack of understanding and experience in this technique. We describe here our experience in performing 346 FNACs. In our opinion, US guided FNACs are highly accurate and safe procedures which can be done on an out-patient basis, with routinely available equipment.

Biopsy, Needle↗
PubMed1990

Ureteral valves: preoperative radiologic diagnosis.

The authors report two cases of congenital ureteral valves that were diagnosed preoperatively in adults. The radiologic, operative and histologic findings are described. A short review of the available literature is also presented. The importance of a confident radiologic diagnosis of this congenital anomaly is emphasized.

Adult↗
PubMedDate not supplied

Multiple reflective channels in the spleen: a sonographic sign of portal hypertension.

We consistently observed small "reflective channels" (RCs) in the splenic parenchyma in patients with portal hypertension (PHT). The purpose of this study was to investigate the frequency of this sign in PHT and in splenic disorders unrelated to PHT compared to normal controls. The significance of this sign in the diagnosis of PHT and in differentiating PHT splenomegalies from others was also assessed. A total of 337 patients underwent sonographic examination of the spleen: 147 normal, 75 non-PHT splenic pathologies, and 115 with PHT. The RCs were scored from grade 0 to 3 by counting the number in an area of 12 mm2 in the splenic parenchyma. Of 222 normal and non-PHT spleens, 174 (78%) showed grade 0, 44 (20%) grade 1, four grade 2 (1%), and none showed grade 3 RCs. Of 115 PHT cases, 17 showed grade 0, 25 grade 1, 44 grade 2, and 29 showed grade 3 RCs. The sensitivity of this sign was 0.85 with a specificity of 0.77 and an accuracy of 0.80 in detecting PHT (p < 0.001). The interobserver and intraobserver variation for grading was insignificant (p > 0.1). The RCs could be explained by periarterial fibrosis and dilatation of venous sinuses with increased collagen in their walls, which is known to occur in PHT. The vascular nature on ultrasound (US) was confirmed by the presence of flow on color Doppler. This sign is readily differentiated from the calcifications of tuberculosis, histoplasmosis, sickle cell infarcts, and phleboliths; it serves as a useful aid in diagnosing and differentiating PHT splenomegaly from non-PHT splenomegaly.

Adolescent↗
PubMedDate not supplied

Tuberculous chylous ascites: pathognomonic CT findings.

The computed tomographic (CT) appearance of chylous ascites is usually that of water with corresponding attenuation coefficients. This case report depicts the fat-fluid level sign on CT (shown by supine and decubitus scans), which is pathognomonic of chylous ascites.

Adult↗