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S Saini

Publications and source records attributed to S Saini.

At least 91 records · Page 5Linked to original sources
PubMed1997

Focal liver lesions: characterization with conventional spin-echo versus fast spin-echo T2-weighted MR imaging.

PURPOSE: To compare prospectively the diagnostic accuracy of T2-weighted conventional spin-echo (SE) and fast SE magnetic resonance (MR) imaging for differentiation of benign (hemangiomas or cysts) from malignant (metastases or hepatocellular carcinoma) liver lesions. MATERIALS AND METHODS: Fifty-three patients with 55 confirmed liver lesions (20 hemangiomas, eight cysts, 22 metastases, four hepatocellular carcinomas, one malignant fibrous histiocytoma) underwent T2-weighted conventional SE (repetition time msec/echo time [TE] msec = 3,100/ 80,160) and fast SE (5,000-5,000/99-104 [effective TE]) MR imaging at 1.5 T. The images were evaluated quantitatively (lesion-liver signal intensity ratio and lesion T2 index [SIlesion TE80/SIlesion TE160, where SI = signal intensity] and qualitatively (blinded reading) by using receiver operating characteristic analysis. RESULTS: Quantitatively, the T2 index (Az = .988) was more accurate than the signal intensity ratio at conventional SE (Az = .920) and fast SE (Az = .910) imaging (P < .05). Qualitatively, there was no statistically significant difference between the blinded reading of conventional SE (Az = .988) and fast SE (Az = .986) images in lesion characterization (benign vs malignant). There was a trend, however, toward superiority of conventional SE imaging for evaluation of "hypervascular" metastases (n = 9). CONCLUSION: With the specific parameters used, conventional SE and fast SE images provide equal accuracy for characterization of focal liver lesions. In patients with hypervascular metastases, double-echo conventional SE images may be preferable.

Adult↗
PubMed1997

Liver metastases: improved detection with dynamic gadolinium-enhanced MR imaging?

PURPOSE: To compare dynamic gadolinium-enhanced with unenhanced magnetic resonance (MR) imaging in detection of liver metastases. MATERIALS AND METHODS: Two groups of patients were prospectively examined with unenhanced and dynamic gadolinium-enhanced MR imaging. The first group (n = 48) had proved liver metastases; the second group (n = 49) did not. One set of unenhanced and one set of gadolinium-enhanced MR images were selected per patient. Three independent, blinded readers assessed the images for presence, number, location, and conspicuity of lesions. Data were analyzed with receiver operating characteristic curves, and contrast-to-noise ratios were calculated for the images. RESULTS: There was no statistically significant difference between the use of unenhanced and gadolinium-enhanced MR images in the differentiation of patients with from patients without metastases. The numbers of false-positive and false-negative diagnoses of individual lesions were higher (not statistically significant) with dynamic MR images than with unenhanced MR images. At dynamic MR imaging, contrast-to-noise ratio was highest in the early phase (30 seconds after injection of the contrast agent) but was not significantly different from the contrast-to noise ratio of the T2-weighted images. CONCLUSION: Dynamic gadolinium-enhanced MR imaging showed no improvement over unenhanced MR imaging in detectability of liver metastases.

Adult↗
PubMed1997

Differentiation of liver hemangiomas from metastases and hepatocellular carcinoma at MR imaging enhanced with blood-pool contrast agent Code-7227.

PURPOSE: To evaluate differentiation of liver lesions at magnetic resonance (MR) imaging enhanced with Code-7227. MATERIALS AND METHODS: Thirty-five patients with 38 proved liver lesions (15 hemangiomas, 17 metastases, six hepatocellular carcinomas [HCCs]) underwent T1-weighted gradient-echo and T2-weighted fast-spin-echo MR imaging at 1.5 T before and after intravenous administration of Code-7227 (1.1 mg iron per kilogram of body weight). RESULTS: In hemangiomas, the mean contrast-to-noise ratio on precontrast and postcontrast images, respectively, increased from -4.51 +/- 4.7 (standard deviation) to 5.19 +/- 6.3 on T1-weighted images and decreased from 14.73 +/- 7.4 to 0.64 +/- 5.1 on T2-weighted images. In comparison, metastases remained hypointense to liver on T1-weighted images (from -5.77 +/- 5.9 to -7.8 +/- 6.8) and hyperintense on T2-weighted images (from 8.73 +/- 5.4 to 12.61 +/- 6.1). Although HCC enhanced more than metastases, they also remained hypointense to liver on T1-weighted images (from -4.87 +/- 6.1 to -1.79 +/- 5.7) and hyperintense on T2-weighted images (from 10.12 +/- 7.9 to 8.7 +/- 6.4). The degree of enhancement on T1-weighted images and of signal intensity drop on T2-weighted images were significantly lower in malignant liver masses than in hemangiomas (P < .001). CONCLUSION: Distinctly different enhancement patterns with Code-7227 helped accurate differentiation of liver lesions.

Adult↗
PubMed1997

Percutaneous gastrostomy with T-fastener gastropexy: results of 316 consecutive procedures.

PURPOSE: To assess the rates of technical success and complications associated with radiologic gastrostomy or gastrojejunostomy performed with T-fastener gastropexy. MATERIALS AND METHODS: In 316 consecutive patients, radiologic gastrostomy or gastrojejunostomy with T-fastener gastropexy was performed over a 10-year period. Results of the procedures were reviewed. Results of follow-up were available for all patients. RESULTS: Of 316 procedures, 314 were successful (technical success rate, 99.4%). Six (1.9%) major complications occurred; 50% occurred in patients with peritoneal involvement from ovarian carcinoma. Ten (3.2%) minor complications occurred. Four minor complications occurred in patients with ovarian cancer and ascites. The 30-day mortality rate was 3.8% (12 patients) with one procedure-related death (0.3%). CONCLUSION: A T-fastener gastropexy may have a protective role in prevention of leakage of gastric contents into the peritoneum in patients with ascites. Ascites need no longer be considered a contraindication for radiologic gastrostomy. A gastropexy enables routine use of larger gastrostomy tubes and ready replacement of a displaced tube even before the development of a mature tract.

Adult↗
PubMed1997

US-guided thoracentesis: requirement for postprocedure chest radiography in patients who receive mechanical ventilation versus patients who breathe spontaneously.

PURPOSE: To identify a population of patients who may not need chest radiography after diagnostic thoracentesis by assessing and comparing the pneumothorax rates in patients with mechanical ventilation (intubation) versus spontaneously breathing patients (no intubation). MATERIALS AND METHODS: A retrospective review of all radiographs, clinical records, and ultrasound (US) scans obtained in 434 patients who underwent US-guided thoracentesis was performed. Three hundred forty-two patients were not intubated and 92 were intubated. Nine patients were excluded because of preexisting pneumothorax. The size of the effusion, the needle size used, and whether a pneumothorax occurred after the procedure were determined. RESULTS: Results demonstrated that only 10 pneumothoraces occurred (six in intubated and four in nonintubated patients). None of the nonintubated patients with pneumothorax and two of the six intubated patients with pneumothorax needed chest tubes. The difference in the pneumothorax rate between intubated and nonintubated patients was statistically significant (P < .01). CONCLUSION: Spontaneously breathing patients who undergo diagnostic thoracentesis do not need postprocedure chest radiography.

Adolescent↗
PubMed1996

Fertilization stimulates an increase in inositol trisphosphate and inositol lipid levels in Xenopus eggs.

Previous experiments from our lab have suggested that the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) is required for sperm-induced egg activation in Xenopus laevis. Here we measure the endogenous production of both Ins(1,4,5)P3 and PIP2 during the sperm-induced and ionomycin-induced calcium wave in the egg and find that both increase following fertilization. Ins(1,4,5)P3 increases 3.2-fold from an unfertilized egg level of 0.13 pmole per egg (0.29 microM) to a peak of 0.42 pmole per egg (0.93 microM) as the calcium wave reaches the antipode in the fertilized egg. This continuous production of Ins(1,4,5)P3 during the time that the Ca2+ wave is propagating across the egg suggests the involvement of Ins(1,4,5)P3 in wave propagation. This increase in Ins(1,4,5)P3 is smaller in ionomycin-activated eggs than in sperm-activated eggs, suggesting that the sperm-induced production of Ins(1,4,5)P3 involves a PIP2 hydrolysis pathway that is not simply raising intracellular Ca2+. While one might expect PIP2 levels to fall as a result of hydrolysis, we find that PIP2 actually increases 2-fold. The total lipid fraction in unfertilized egg exhibits 0.8 pmole PIP2 per egg and this increases to 1.5 pmole as the calcium wave reaches the antipode. The PIP2 concentration peaks 2 min after the completion of the calcium wave at 1.8 pmole per egg. The amount of PIP2 in the animal and vegetal hemispheres of the egg was also measured by cutting frozen eggs in half. The vegetal hemisphere contained twice the amount of PIP2 as the animal hemisphere but it also contained twice the amount of lipid. Thus, there was an equivalent amount of PIP2 normalized to lipid in each hemisphere. Isolated animal and vegetal hemisphere cortices exhibit similar PIP2 concentrations, suggesting that the 2-fold higher total PIP2 in the vegetal half is not due to a gradient of PIP2 in the plasma membrane, but rather implies that cytoplasmic organelle membranes also contain PIP2.

Animals↗
PubMed1996

Gadolinium-DTPA enhanced echoplanar MR imaging of the liver: preliminary observations.

This study describes our preliminary experience with dynamic gadopentetate dimeglumine enhanced echoplaner MR imaging (EPI) in fifteen patients with focal liver lesions. Lesion diagnosis was established by histology (n = 3) or typical imaging characteristics (exclusive of the EPI study) combined with clinical follow up (n = 12). Dynamic gadopentetate dimeglumine (0.1 mmol/kg) enhanced MR imaging was performed on a commercially available 1.5 T EPI equipped MR system using a single-excitation fat-suppressed inversion recovery pulse sequence. The choice of an IR sequence allowed nulling of the lesion signal by varying T1 prior to enhancement creating the optimal conditions for qualitative inspection of the enhancement profile. Intershot delay (defined as TR) ranged from 1-5s. Image analysis was performed qualitatively by two radiologists. Benign and malignant lesions displayed temporal enhancement profiles compatible with characteristic findings expected with conventional imaging modalities. Further refinements in our technique and expanded system capabilities will allow dynamic imaging of the entire liver with improved temporal resolution over conventional sequences.

Contrast Media↗
PubMed1996

T2 relaxation times of hypervascular and non-hypervascular liver lesions: do hypervascular lesions mimic haemangiomas on heavily T2-weighted MR images?

AIM: To correlate the T2 relaxation times of liver lesions with their vascularity at angiography and to determine whether hypervascular lesions have similar signal intensity to haemangiomas on heavily T2-weighted MR images. PATIENTS AND METHODS: Thirty-four patients with histologically proven malignant liver lesions had both angiography and T2W (SE 3000/80,160) MR imaging (1.5 T) of the liver. Angiographically, the lesions were hypervascular in 15 and non-hypervascular in 19 patients. Fifteen additional patients with proven haemangioma also had MR imaging during the same time period. The T2 relaxation time of a representative lesion was calculated for each patient and the results compared. RESULTS: The mean T2 time for hypervascular lesions was 76 +/- 21 ms compared with 79 +/- 18 ms for non-hypervascular lesions (P = 0.61). The mean T2 relaxation time for haemangiomas was significantly longer than either group: 147 +/- 46 ms (P = 0.0001). CONCLUSION: The T2 relaxation times of hypervascular and non-hypervascular liver lesions are similar and are significantly shorter than those of haemangiomas. Therefore, hypervascular lesions should not mimic haemangiomas on heavily T2-weighted images.

Carcinoma, Hepatocellular↗
PubMed1996

Mn-DPDP enhanced MR imaging of the liver: analysis of pulse sequence performance.

AIM: To compare liver enhancement and lesion-liver contrast on T1-weighted (T1W) gradient recalled echo (GRE), spin-echo (SE) and fat-suppressed SE (FS-SE) pulse sequences at Manganese-DPDP (Mn-DPDP) enhanced magnetic resonance (MR) imaging of the liver. PATIENTS AND METHODS. Twenty-one patients with known liver lesions were administered 5 mumol/kg of Mn-DPDP. TIW GRE (78/2.3/80 degrees), SE and F-SE (300/12) images were obtained before and 15 min after Mn-DPDP. Signal/noise ratio (SNR) and lesion-liver contrast/noise ratio (CNR) were calculated for each pulse sequence. RESULTS: Liver SNR (n = 21) and lesion-liver CNR (n = 10) increased significantly after Mn-DPDP on all three pulse sequences (P < 0.0001). Liver SNR was highest on the FS-SE and GRE pulse sequences (FS-SE = 43.8, GRE = 38.4, SE = 29.2). Lesion-liver CNR was highest on the FS-SE pulse sequence (FS-SE = -29.3, SE = -23.2, GRE = -19.8), which was significantly higher than the GRE pulse sequence (P < 0.05). CONCLUSION: The T1-weighted fat-suppressed SE (FS-SE) pulse sequence provides highest liver enhancement and lesion-liver contrast and is recommended for Mn-DPDP enhanced MR imaging.

Adult↗
PubMed1996

Preoperative staging of cancer of the pancreas: value of MR angiography versus conventional angiography in detecting portal venous invasion.

OBJECTIVE: The purpose of this study was to compare contrast-enhanced MR angiography with conventional catheter angiography for detecting portal venous invasion in the preoperative staging of pancreatic cancer, using the surgical confirmation of vascular involvement as the standard of truth. SUBJECTS AND METHODS: MR and conventional angiography were performed in 20 patients with pancreatic carcinoma, with surgical confirmation in all cases. MR angiography was performed at 1.5 T, with coronal (2.9 mm) and axial (6.0 mm) contrast-enhanced breath-hold two-dimensional time-of-flight imaging. Data from each imaging technique were collected prospectively and analyzed in a blinded fashion by expert vascular radiologists. Vascular involvement in each patient and in each vessel (main portal vein, confluence, splenic vein, and superior mesenteric vein) determined whether the tumor was resectable (normal, abutment) or nonresectable (encased, occluded). Surgical confirmation of the vascular involvement of the portal venous structures was used as the standard of truth in all patients. RESULTS: Among the 20 patients, 11 tumors were surgically resectable and seven were nonresectable with performance of a palliative bypass. MR angiography and conventional angiography had an overall concordance in 65% of patients (13/20; seven resectable, four nonresectable, two false-negatives) on the basis of the vascular status in each patient of the portal venous structures and in 84% (47/56) of the individual vessels surgically confirmed. MR angiography correctly identified 11 of 11 resectable patients and five of nine nonresectable patients, with four false-negative cases. Conventional angiography correctly identified seven of 11 resectable patients and six of nine nonresectable patients, with three false-negative cases and four false-positive cases. CONCLUSION: The lack of false-positives by MR angiography suggests that MR imaging may provide a noninvasive screen for nonresectability on the basis of vascular involvement, with no patients with potentially resectable tumors being denied surgery by MR angiography in this cohort. However, the presence of false-negatives using MR angiography indicates the procedure would still not fully eliminate unnecessary laparotomies.

Aged↗
PubMed1996

MR contrast material for vascular enhancement: value of superparamagnetic iron oxide.

OBJECTIVE: The purpose of this study were to quantify abdominal vascular enhancement and to prove the feasibility of iron oxide-enhanced MR angiography in humans using three doses of superparamagnetic iron oxide agent AMI 227. SUBJECTS AND METHODS: Sixteen patients randomly received either 0.8, 1.1, or 1.7 mg Fe/kg of ultrasmall superparamagnetic iron oxide agent AMI 227. T1-weighted breath-hold gradient-echo images were obtained before and 45 min after i.v. administration of AMI 227. Signal intensity was measured in the aorta, the inferior vena cava, the portal vein, and muscle on unenhanced and contrast-enhanced images. Signal-to-noise ratios and enhancement [(SNR after contrast-SNR before contrast) / SNR before contrast] were calculated. Vessels were visually graded before and after administration of AMI 227. RESULTS: All vessels showed statistically significant enhancement 45 min. after administration of AMI 227 by both qualitative and quantitative measures (p < .001). There was no significant increase in noise or signal intensity of muscle after contrast material was administered. The amount of enhancement was not statistically significantly different among the three doses. CONCLUSIONS: AMI 227, which is currently in phase III clinical trials, demonstrates significant vascular enhancement and may prove useful as an MR angiographic contrast agent.

Adult↗
PubMed1996

Liver. II: Iron oxide-based reticuloendothelial contrast agents for MR imaging. Clinical review.

Iron oxide-based compounds are a new class of MR contrast agents that have a wide range of clinical applications. The biodistribution and subsequent influence on the MR image depends on the particle size. Iron oxides can be used to increase contrast-to-noise ratio, facilitating the visibility of focal liver lesions. Other applications include blood-pool imaging and targeting the reticuloendothelial system and cell surface receptors.

Contrast Media↗