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S Saini

Publications and source records attributed to S Saini.

At least 217 records · Page 12Linked to original sources
PubMed1989

Routine sonographic techniques fail to quantify gallstone size and number: a retrospective study of 111 surgically proved cases.

We analyzed sonographic images retrospectively to determine their value in quantifying gallstone size and number in 111 surgically proved stone-containing gallbladders for which routine preoperative sonograms were available. The number and size of of stones found on pathologic examination were correlated with the results of image analysis. In patients with more than one stone, observable size differences were recorded if the smallest stone diameter was less than 50% of the largest stone diameter. Estimates of gallstone size and number from preoperative sonograms were correct in only 23 (21%) of 111 cases. Stone size and number were overestimated as often as they were underestimated. Stones of a uniform size were recognized correctly in 59 (92%) of 64 cases. Stones of two different sizes were correctly identified in only 14 (30%) of 47 cases; the second, smaller stones were missed in 26 (79%) of 33 cases. These findings indicate poor sonographic characterization of gallbladder contents when imaging studies are performed solely to determine the presence or absence of gallstones.

Cholelithiasis↗
PubMed1989

Detection of hepatic metastases with MR imaging: spin-echo vs phase-contrast pulse sequences at 0.6 T.

The purpose of this study was to compare the sensitivity of T1-weighted and T2-weighted spin-echo (SE) pulse sequences with T2-weighted phase-contrast (PC) imaging techniques for the detection of hepatic metastases. Pulse-sequences performance was evaluated in 52 consecutive patients with 88 hepatic metastases who underwent MR imaging at 0.6 T. Lesion-liver contrast-to-noise ratios (CNR) on SE 260/14 (-12.4 +/- 6.7) and PC 2350/60 (+10.8 +/- 4.2) images were significantly (p less than .05) greater than on SE 2350/60 (+ 7.8 +/- 3.9), SE 2350/120 (+8.1 +/- 4.8), SE 2350/180 (+7.9 +/- 4.5), and PC 2350/30 (+4.6 +/- 2.9) images. Sensitivity for detection of 88 individual metastases was comparable on SE 260/14 (78 of 88 patients) and PC 2350/60 (81 of 88 patients) images and was significantly (p less than .05) greater than on in-phase T2-weighted SE images (TE = 60, 70 of 88 patients; TE = 120, 69 of 88 patients; TE = 180, 65 of 88 patients). Histologic analysis of tumor-free liver showed fatty change in 11 of 13 specimens available for pathologic evaluation. In all 11 of those patients, PC images increased tumor-liver contrast in comparison with the in-phase SE images. This analysis suggests that for detection of hepatic metastases at midfield strengths, the T1-weighted, short TR/short TE (SE 260/14) and the T2-weighted, phase-contrast (PC 2350/60) pulse sequences offer comparable performance.

Adult↗
PubMed1989

Pleural interventions. Indications, techniques, and clinical applications.

Pleural interventions represent one of the newest frontiers of interventional radiology. Many of the data are preliminary, but it is tempting to postulate that future side-by-side comparisons would prove these innovations superior to unguided techniques. Each procedure utilizes similar principles of pleural intervention yet emphasizes unique issues pertinent to the disease processes involved.

Diagnostic Imaging↗
PubMed1988

Gd-DOTA: characterization of a new paramagnetic complex.

The relaxivity, biodistribution, and toxicity of the gadolinium-tetraazacyclododecanetetraacetic acid (Gd-DOTA) complex were evaluated. This cyclic complex has much greater in vitro stability (10(28)) than similar noncyclic complexes such as gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) (10(23)) or gadolinium-ethylenediaminetetraacetic acid (Gd-EDTA) (10(17)). The T1 relaxivity of Gd-DOTA (meglumine salt) determined in saline and in liver tissue at 20 MHz was similar to the relaxivity of Gd-DTPA. Tissue proton relaxation enhancement (PRE) correlated closely with chemical measurement of tissue gadolinium concentration. In rats, the biodistribution of Gd-DOTA was similar to Gd-DTPA with a distribution half-life of 3 minutes and an elimination half-life of 18 minutes. The median lethal dose (LD50) in mice of Gd-DOTA was 93% higher than that of Gd-DTPA; the calculated safety factor (ratio of LD50 to effective dose) was 53 for Gd-DOTA and 28 for Gd-DTPA. The data suggest that in vitro stability correlates with in vivo safety.

Animals↗
PubMed1988

Complicated pancreatic abscesses: problems in interventional management.

Twenty-five patients with grade D or E pancreatitis underwent percutaneous drainage. These patients required multiple computed tomography (CT) examinations, multiple catheter insertions, multiple catheter manipulations, and long-term catheter drainage. Eight of the 25 patients were successfully treated with catheter drainage alone. Sixteen underwent surgical drainage, ten after attempts at percutaneous drainage and six prior to radiologic drainage. Of the ten patients who had initial percutaneous drainage, only four were clinically improved from the drainage procedure alone. Although the fluid component of the abscess was often adequately drained in all ten patients, surgery was required to remove pieces of necrotic debris. Six patients who underwent surgical debridement had residual abscesses in the post-operative period and were all successfully treated with percutaneous drainage. One patient died from unrelated causes. Successful interventional management of patients with pancreatic abscesses requires intensive radiologic intervention and monitoring and may be better served by a combination of radiologic and surgical means.

Abscess↗
PubMed1988

Superparamagnetic iron oxide: clinical application as a contrast agent for MR imaging of the liver.

Superparamagnetic iron oxide (ferrite) particles were evaluated as a contrast agent for magnetic resonance (MR) imaging. In this pilot study, doses ranging from 10 to 50 mumol/kg were administered intravenously to 15 patients. Ferrite-enhanced images of the liver obtained with standard pulse sequence techniques significantly increased the number of hepatic lesions detected (P less than .01) and reduced the threshold size for detection to 3 mm (P less than .01). The improved clinical performance of ferrite-enhanced images correlated with significant increases in measured contrast-to-noise ratios (P less than .01). Degradation of superparamagnetic activity and/or clearance of ferrite from the liver was demonstrated as early as 12 hours after injection, suggesting that the lack of chronic toxicity observed in animal studies may be reproduced in humans. These initial clinical results appear to confirm extensive preclinical data indicating that ferrite administered at a dose of 20 mumol/kg has the potential to significantly improve the performance of abdominal MR imaging.

Adult↗
PubMed1988

Image-guided pleural biopsies: indications, technique, and results in 23 patients.

Twenty-six pleural biopsies were performed on 23 patients over a 3-year period. Twenty-three biopsies were performed guided with ultrasound; one, with computed tomography; and two, with fluoroscopy. Indications for an image-guided pleural biopsy were (a) pleural masses or thickening that were either not seen on chest radiographs or seen only on one view and (b) small or loculated pleural effusions of unknown cause with no mass seen. If only pleural fluid was present, reverse bevel needles were used for biopsy (n = 15). If a discrete pleural mass or thickening was seen with cross-sectional imaging, standard (16-20 gauge) biopsy needles were used (n = 11). In the 23 patients, biopsy results were true positive in ten (nine with malignancy, one with tuberculous pleurisy), true negative in ten (confirmed either at subsequent thoracotomy or clinical follow-up), and false negative in three. Complications were few, with a significant pneumothorax occurring in two patients (8.7%). Image-guided biopsy of small pleural lesions and small pleural effusions can be performed by the radiologist who understands the special needles and techniques involved.

Biopsy, Needle↗
PubMed1988

Thoracic empyema: management with image-guided catheter drainage.

Forty-three patients with thoracic empyema were treated by means of image-guided catheter drainage. In 40 patients, image-guided catheter drainage was the primary treatment method; in three it was used after conventional, surgical chest tube placement failed. Drainage was performed with ultrasound guidance in 30 patients (69.8%), computed tomography in eight (18.6%), and fluoroscopy in five (11.6%). A combination of guidance modalities was used in six patients. Image-guided catheter drainage alone was successful in 31 of 43 patients (72.1%). In three patients (7%), empyemas were initially drained, but a thoracotomy was ultimately required because of a persistent pleural peel. In eight patients (18.6%), the procedure failed, predominantly due to tube clogging, persistent pneumothorax, or progressive development of a pleural peel. In one patient, drainage was successful but he died 10 days later of complications of renal failure. No major complications were encountered. Treatment of these patients requires a thorough understanding of the pathogenesis of pleural space infection, principles of empyema drainage, techniques of abscess drainage under image guidance, and the use of a pleural drainage system.

Adult↗
PubMed1988

Superparamagnetic iron oxide: enhanced detection of focal splenic tumors with MR imaging.

Superparamagnetic iron oxide (AMI-25), a reticuloendothelial cell-specific contrast agent for magnetic resonance (MR) imaging, was evaluated for its ability to permit detection of splenic metastases in 18 patients. Superparamagnetic iron oxide, at a dose of 30 mumol of iron per kilogram, decreased the signal intensity of spleen from 19.5 +/- 4.8 to 3.1 +/- 2.2 (spin-echo sequence, repetition time msec/echo time msec = 1,500/42; P less than .05), without changing the signal intensity of tumor. As a result, the tumor-spleen contrast-to-noise ratio increased from 0.2 (tumor isointense relative to spleen) to 18.0 (tumor hyperintense relative to spleen). As a consequence of increased contrast, splenic tumors were detected in four of 18 patients (45 individual lesions; P less than .05), whereas nonenhanced MR imaging permitted detection of splenic lesions in only two of 18 patients (four individual lesions). Maximum tumor-spleen contrast was achieved within 60 minutes after intravenous administration. These initial clinical results indicate that MR imaging with superparamagnetic iron oxide may offer improved accuracy in the diagnosis of splenic tumors.

Adenocarcinoma↗
PubMed1988

Pyogenic liver abscess: contrast-enhanced MR imaging in rats.

MR imaging was used to evaluate experimentally induced pyogenic liver abscesses in an animal model. Rats were examined before and after IV administration of either gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA), ferrite particles, or both contrast agents together. Pyogenic liver abscesses appeared hypointense on T1-weighted images and hyperintense on T2-weighted images. Bolus administration of Gd-DTPA using a fast spin-echo sequence with repetition time of 250 msec and echo time of 20 msec (SE 250/20) showed transient selective enhancement of normal hepatic tissue and increased lesion conspicuity, quantitatively assessed by the contrast-to-noise ratio, which increased from -35.7 to -59.0. Delayed leakage of Gd-DTPA into the abscess center partially obscured small lesions at 30-60 min. Ferrite particles reduced the signal intensity of normal liver, and the abscess then appeared homogenously hyperintense. Applying the SE 500/32 sequence, the contrast-to-noise ratio increased from -1.2 to +74.0. Coordinated administration of both contrast agents showed a further increase in contrast to +94.0, with a hyperintense abscess rim surrounded by hypointense liver. Gd-DTPA increases abscess-liver contrast by rim enhancement of the abscess wall, and ferrite increases the abscess-liver contrast by selectively decreasing the signal intensity of surrounding normal liver. As a result of increased contrast-to-noise ratio, both contrast agents, alone or in combination, increase the conspicuity of hepatic abscesses.

Animals↗
PubMed1988

Dual-contrast MR imaging of liver cancer in rats.

MR contrast agents increase hepatic tumor conspicuity, as measured in terms of contrast-to-noise (C/N) ratios. With an animal model of hepatic metastases from breast cancer, IV administration of Gd-DTPA (0.2 mmol/kg) shows a biphasic time response, transiently increasing the signal intensity of liver relative to tumor, with C/N ratio magnitudes increasing from -5.7 to -16.3 (SE 250/20); after a delay, the signal intensity of tumor increases relative to liver with a reversal of the C/N sign from negative to positive and an increase in the C/N magnitude to +25.0. IV administration of ferrite particles (0.05 mmol Fe/kg) shows a monophasic time response, increasing signal intensity of tumor relative to liver from +1.5 to +49.5 (SE 500/30). When both contrast agents were administered together (dual-contrast technique), the tumor-liver C/N magnitude reached a maximum of +67.8 (SE 500/30) 12 min after drug infusion. Analysis of individual contrast and noise factors contributing to this technique revealed a strong correlation between the signal intensity of liver and the signal intensity of ghost artifacts, which increase after administration of Gd-DTPA (r = .89) and decrease after administration of ferrite (r = 1.0). Dual-contrast imaging shows a synergistic addition of contrast and suppression of noise from ghost artifacts, maximizing the C/N and increasing the conspicuity of focal liver lesions.

Animals↗