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Biomedical subjects

S Saini

Publications and source records attributed to S Saini.

At least 181 records · Page 10Linked to original sources
PubMed1991

Focal nodular hyperplasia of the liver: MR findings in 35 proved cases.

MR images of 28 patients with 35 lesions of hepatic focal nodular hyperplasia were reviewed to determine the frequency of findings considered typical of this condition (isointensity on T1- and T2-weighted pulse sequences, a central hyperintense scar on T2-weighted images, and homogeneous signal intensity). Fifteen lesions were imaged at 0.6 T with T1- and T2-weighted spin-echo (SE) pulse sequences; 20 lesions were imaged at 1.5 T with T1-weighted SE and gradient-echo pulse sequences and T2-weighted SE pulse sequences. Diagnosis of focal nodular hyperplasia was made pathologically in 25 patients, with nuclear scintigraphy in four, and with follow-up imaging in six. Only seven lesions (20%) were isointense relative to normal liver on both T1- and T2-weighted images. On T1-weighted SE images, 21 lesions (60%) were isointense relative to normal liver, 12 (34%) were hypointense, and two (6%) were hyperintense. On T2-weighted SE images, 12 lesions (34%) were isointense and 23 (66%) were hyperintense relative to normal liver. A central scar was present in 17 lesions (49%) and was hypointense relative to the lesion on T1-weighted images and hyperintense on T2-weighted images. Twenty lesions (57%) were of homogeneous signal intensity throughout the lesion, except for the presence of a central scar. All three MR imaging characteristics were present in three cases (9%). We conclude that hepatic focal nodular hyperplasia has a wide range of signal intensity on MR imaging.

Adult↗
PubMed1991

Treatment of critically ill patients with sepsis of unknown cause: value of percutaneous cholecystostomy.

Because of the difficulty in diagnosing acute cholecystitis in critically ill patients with severe intercurrent illness by clinical and imaging methods or percutaneous aspiration of the gallbladder, a trial of percutaneous cholecystostomy was performed in 24 patients in the intensive-care unit with persistent, unexplained sepsis after a complete clinical, laboratory, and radiologic search showed no alternative source of infection. Persistent high fevers, despite antibiotic therapy, were present in all patients, with elevated WBC count in 18 patients, vague abdominal tenderness in 11, and septic shock requiring vasopressors in 15. Sonographically, all patients had distended, spherical gallbladders, six had gallstones, eight had wall thickening, three had pericholecystic fluid, and four had Murphy's sign. All patients were seen by a senior abdominal surgeon, who agreed to a trial of percutaneous cholecystostomy. Fourteen patients (58%) responded to percutaneous cholecystostomy, as evidenced by a decrease in WBC count, defervescence, and the ability to be weaned off vasopressors. Bile cultures were positive in four patients. Ten patients (42%) did not respond to percutaneous cholecystostomy; five eventually died of unrelated causes. A respiratory source of infection was eventually found in three of these 10 patients, with no proved source of infection in the remainder. No complications related to catheter insertion occurred in this group of patients. Bile leaks occurred in two patients when the percutaneous cholecystostomy catheter was removed, but without serious consequence. Our experience suggests that a lower threshold for performing percutaneous cholecystostomy in this difficult clinical subset of patients is worthwhile.

Acute Disease↗
PubMed1991

Differentiation between hemangiomas and metastases of the liver with ultrafast MR imaging: preliminary results with T2 calculations.

We studied the efficacy of T2 measurements at high field strength in distinguishing between liver hemangiomas and hepatic metastases when an ultrafast (single-excitation) MR imaging technique is used. Fourteen patients with known liver tumors were imaged in a 2.0-T prototype ultrafast MR scanner with a spin-echo (infinite TR and TE of 30-340 msec) pulse sequence. Each image was obtained with a total data acquisition time of 20 msec. T2 calculations for hepatic metastases (n = 6) showed a mean of 79.3 +/- 13.5 msec, whereas hemangiomas (n = 8) showed a T2 of 139.8 +/- 18.8 msec (p less than .0001). T2 values of lesions had a smaller relative standard deviation than previously reported, and the range of T2 values of hemangiomas (119-181 msec) and metastases (68-103 msec) did not overlap. Our preliminary results suggest that T2 calculations with ultrafast MR imaging may be useful for differentiating hemangiomas from metastases. We hypothesize that T2 values obtained from ultrafast MR images are more reliable than those obtained from conventional MR images, primarily because of the elimination of T1 information and effects of motion on image signal intensity.

Carcinoid Tumor↗
PubMed1991

Percutaneous dilatation of benign biliary strictures: single-session therapy with general anesthesia.

Percutaneous biliary stricture dilatation (PBSD) is an uncomfortable procedure for patients that presently requires multiple dilatation sessions spread over many days. We evaluated the use of general anesthesia to enable PBSD to be performed in a single sitting in 14 patients with benign biliary strictures (11 anastomotic and three iatrogenic strictures). Four patients had multiple strictures, and the other 10 had a single stricture. Strictures were documented by transhepatic cholangiography (11 patients) or T-tube cholangiography (three); quantitative biliary perfusion studies were additionally performed in seven cases. Dilatation was performed transhepatically in 11 patients and via a T-tube track in three. Balloons ranged from 8 to 12 mm in diameter and were manually inflated for 3 min with an average of five inflations per stricture. Stenting catheters were left across the strictured areas in all patients for 6-21 days (mean, 10 days) before removal. The mean duration of hospital stay for all patients was 5.7 days, which could further be divided into means of 3.6 days (range, 1-6 days) for 11 patients without complications and 13.7 days (range, 13-14 days) for three patients who had complications. Complications included cholangitis; liver hematoma (which resolved with conservative therapy in both cases); and pseudoaneurysm of the hepatic artery, which necessitated angiographic embolization. PBSD achieved long-term patency in 13 (93%) of 14 patients with a follow-up period of 2.0 to 5.5 years (mean, 3.2 years). A stricture recurred in one patient 1.5 years after dilatation. We conclude that PBSD with the patient under general anesthesia can be performed in a single visit to the radiology department with excellent long-term patency rates, a shorter hospital stay, and a pain-free procedure for the patient.

Adolescent↗
PubMed1991

[Magnetic resonance tomographic diagnosis of a myelolipoma of the adrenal glands].

Myelolipoma is an uncommon, benign, adrenal lesion composed of fatty tissue and bone marrow elements. The presence of fat within this tumor is the key factor in identification and noninvasive diagnosis with imaging methods. Since fat has a characteristic behavior reflected by the MR signal intensity, a specific diagnosis can be made by MRI.

Adrenal Gland Neoplasms↗
PubMed1990

Clinical application of superparamagnetic iron oxide to MR imaging of tissue perfusion in vascular liver tumors.

Previous studies of AMI-25, a particulate iron oxide magnetic resonance contrast agent, imaged liver tumors 1 or more hours after injection, in the retention phase after complete clearance of AMI-25 from the circulation. In the present study, imaging was performed in the distribution phase, during the first 12 minutes after injection while contrast agent remain in circulation, and these images were compared with those obtained in the retention phase. Nineteen patients with cancer were studied, including 15 imaged during the distribution phase. T2-weighted distribution phase images demonstrated 90% of the lesions detected by means of T2-weighted retention phase images, showed a 3.5-fold increase in contrast-to-noise ratio over images obtained before administration of AMI-25, and increased diagnostic confidence by reducing signal from small intrahepatic blood vessels. Distribution phase images showed little contrast agent uptake by cancer tissue. Both distribution and retention phase images demonstrated greater contrast agent uptake by hemangiomas than by malignant neoplasms (P less than .01). The use of both distribution phase and retention phase AMI-25-enhanced images offers improved diagnostic accuracy in the detection and characterization of focal liver lesions.

Adenocarcinoma↗
PubMed1990

Gallstone fragmentation with contact electrohydraulic lithotripsy: in vitro study of physical and technical factors.

To identify physical and technical factors that have an effect on fragmentation, the authors performed in vitro contact electrohydraulic lithotripsy (EHL) on gallstones 10 mm or larger in size. Of 122 gallstones, 113 (93%) could be fragmented with 1-46 pulses from a 3-F electrode (average, 10 pulses). Only 12 of the 113 stones could be fragmented with a single spark. Of the nine stones that did not fragment with 50 pulses from a 3-F electrode, four were larger than 30 mm in diameter, and five were seen at radiography to be heavily calcified; all of these stones were fragmented with five or fewer pulses from a 9-F electrode. Stone capture in a wire basket facilitated fragmentation of gallstones of all sizes, but particularly those stones 15 mm or larger. Contact EHL could be performed as well in a 1:1 dilute diatrizoate irrigating solution as in 1:6 normal saline. A significantly greater number of pulses was required to fragment gallstones 15 mm in diameter or larger compared with stones smaller than 15 mm (P less than .01). In addition, stones 15 mm or smaller had a greater tendency to fragment into "gravel" (ie, fragments measuring 2 mm or less), while EHL of stones larger than 15 mm produced larger, discrete fragments of approximately equal size (P less than .05). EHL of heavily calcified gallstones required a significantly greater number of pulses than EHL of less calcified or noncalcified stones (P less than .002).

Cholelithiasis↗
PubMed1990

Simulation of gallstone fragments by cavitation bubbles during extracorporeal shock wave lithotripsy: physical basis and in vitro demonstration.

During extracorporeal shock wave lithotripsy of gallstones, sonography often shows a swirling pattern of echogenic foci shortly after the application of shock waves. This effect has been thought to represent gallstone fragments in suspension. However, evidence suggests that this finding is in part due to cavitation, a physical phenomenon associated with the formation or movement of gas bubbles in the fluid-filled gallbladder. Condoms filled with degassed water and five human bile specimens were positioned in the focus of an MPL 9000 lithotriptor (Dornier Medical Systems, Munich). A solitary nonradiopaque gallstone was then added to a bile-filled condom, and the sonographic pattern was observed before and after fragmentation. The mean clearance time of the cavitation bubbles was 4 seconds for degassed water and 22 seconds for human bile. Gallstone fragments were distinguished from cavitation bubbles by their prolonged settling time (up to 30 minutes) along the dependent gallbladder wall.

Bile↗
PubMed1990

First clinical trial of a new superparamagnetic iron oxide for use as an oral gastrointestinal contrast agent in MR imaging.

The authors report the results of preclinical testing and initial clinical application of a superparamagnetic iron oxide specifically prepared as a contrast agent for magnetic resonance (MR) imaging of the gastrointestinal tract. MR imaging was performed at 0.6 and 1.5 T in 15 volunteers. Images of the upper abdomen and pelvis were obtained before and after ingestion of the contrast material at doses of 22.5-225.0 mg of iron in 600-900 L. Two readers scored the images. Delivery of contrast material into the proximal and distal small bowel, with obvious loss of signal intensity (T2 enhancement), was achieved in all subjects. Enhanced images showed improved delineation of the head and tail of the pancreas, anterior margins of the kidneys, and paraaortic region. The contrast agent did not generate artifacts, an improvement over prototype formulations evaluated previously in animals. Except for a brief episode of diarrhea in five subjects, the agent was well tolerated. Use of this contrast agent improved the diagnostic quality of abdominal MR images by enabling the distinction of the bowel from nonbowel structures at concentrations that did not produce image distortion.

Adult↗
PubMed1990

Hepatic tumors: quantitative tissue characterization with MR imaging.

To determine which quantitative methods of image analysis are most suitable for the differential diagnosis of benign and malignant hepatic lesions, the authors analyzed magnetic resonance images obtained at 0.6 T in 42 patients with proved hepatic cavernous hemangioma and 63 patients with various hepatic malignancies. The lesion-liver signal-intensity ratio for images obtained with a repetition time of 2,350 msec and echo time of 180 msec was most helpful in distinguishing hemangiomas from cancer (area under the receiving operator characteristic curve [ROC] = 0.99 +/- 0.005). All 38 lesions with lesion-liver signal-intensity ratios greater than 3.5 were hemangiomas, whereas all 57 hepatic tumors with a ratio less than 2.5 were malignant neoplasms. A specificity of 93% and sensitivity of 89% can be achieved with use of quantitative signal-intensity data only. The authors conclude that in conjunction with heavily T2-weighted pulse sequences, signal-intensity ratios are an important adjunct to morphologic analysis in the differential diagnosis of hepatic neoplasms.

Adult↗
PubMed1990

Occlusion of biliary endoprostheses: presentation and management.

A retrospective review of 20 cases of endoprosthesis occlusion in 17 patients was performed. The average length of stent patency before occlusion was 3.7 months. Clinical manifestations included one or a combination of the following: cholangitis (n = 17), jaundice (n = 9), and leakage of bile or purulent material from the percutaneous insertion site (n = 6). Eighteen of 20 episodes of endoprosthesis occlusion were successfully managed with normalization of biochemical parameters and alleviation of clinical manifestations. No therapy was attempted in two episodes of stent occlusion due to widespread metastatic disease. All 17 patients received intravenous fluid replacement and broad-spectrum antibiotic therapy. This was sufficient therapy to relieve symptoms in two cases of occlusion. Occluded stents were removed in the other 16 patients by means of radiologic (n = 10) or endoscopic (n = 6) methods. After the acute septic episode had subsided (2-5 days; mean, 3 days), new endoprostheses were percutaneously inserted in 10 cases of occlusion, long-term internal-external catheters were placed in five, and surgical bypass was performed in one. The authors conclude that endoprosthesis occlusion should not be considered a terminal event in patients with malignant biliary disease.

Aged↗
PubMed1990

Percutaneous cecostomy: controlled transperitoneal approach.

The authors present two cases of percutaneous cecostomy performed with a modified approach previously described for percutaneous gastrostomy and cholecystostomy. T-fastener devices were used to affix the cecum to the anterior abdominal wall; thus, the potential problem of fecal spillage was prevented. In both cases, adequate fecal drainage was provided without complication.

Aged↗
PubMed1990

Segmented turboFLASH: method for breath-hold MR imaging of the liver with flexible contrast.

A method called segmented turboFLASH imaging allows high-resolution, multisection, short-inversion-time (TI) inversion-recovery (STIR), T1- or T2-weighted magnetic resonance (MR) studies of the liver to be completed within a breath-hold interval. The method was applied in a phantom and in 19 patients with hepatic lesions. Sequence comparisons were performed among segmented turboFLASH, single-shot turboFLASH, T1-weighted gradient-echo with ultrashort echo time, and T2-weighted spin-echo (SE) techniques. Signal from fat and liver could be nulled with the segmented turboFLASH method, with TIs of 10 and 300 msec, respectively; signal from these tissues could not be eliminated with the single-shot approach. Signal-difference-to-noise ratios and contrast for the best segmented sequences were comparable with those of the best T2-weighted SE and T1-weighted gradient-echo techniques. It is concluded that it is feasible to obtain breath-hold images with arbitrary tissue contrast by means of segmented turboFLASH imaging. The method may prove helpful for the detection and characterization of hepatic lesions and will likely have applications to other anatomic regions such as the chest and pelvis.

Adenoma, Bile Duct↗