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Dushyant Sahani

Publications and source records attributed to Dushyant Sahani.

At least 19 recordsLinked to original sources
PubMed2006

Contrast-induced nephropathy in patients with chronic kidney disease undergoing computed tomography: a double-blind comparison of iodixanol and iopamidol.

BACKGROUND: Based on a single clinical trial, it has been suggested that the contrast agent iodixanol, which is isotonic to human plasma, may be less nephrotoxic than other nonionic contrast agents in renally impaired patients after intra-arterial injection. We compared the effects on renal function of iopamidol-370 injection (796 mOsm/kg) and iodixanol-320 (290 mOsm/kg) in patients with chronic kidney disease undergoing contrast-enhanced multidetector computed tomography (CE-MDCT) examinations using a multicenter, double-blind, randomized, parallel-group design. METHODS: A total of 166 patients with stable moderate-to-severe chronic kidney disease (screening and baseline serum creatinine, SCr, > or =1.5 mg/dL and/or creatinine clearance, CrCl, < or =60 mL/min) who were undergoing CE-MDCT of the liver or peripheral arteries were randomized to receive equi-iodine IV doses (40 gI) of either iopamidol-370 (370 mgI/mL) or iodixanol-320 (320 mgI/mL) at 4 mL/s. SCr and CrCl were obtained at screening, baseline, and at 48-72 +/- 6 hours after dose (mean, 57.4 hours). Contrast-induced nephropathy (CIN) was defined as an absolute increase > or =0.5 mg/dL (44.2 micromol/L) and/or a relative increase in SCr > or =25% from baseline. RESULTS: A total of 153 patients were included in the final analysis (13 patients excluded because of lack of follow-up, hemodialysis to remove contrast, average daily CrCl variation >1% at screening). The 2 study groups were comparable with regard to age, gender distribution, the presence of diabetes, concomitant medications, hydration, and contrast dose. Mean predose SCr was 1.6 +/- 0.4 mg/dL in both groups (P = 0.9). An absolute increase > or =0.5 mg/dL (44.2 micromol/L) in SCr was observed in none of the patients receiving iopamidol-370 and in 2.6% (2/76) of patients receiving iodixanol-320 (95% confidence interval -6.2, 1.0, P = 0.2). A relative increase > or =25% in SCr occurred in 4% (3/77) of patients receiving iopamidol-370 and in 4% (3/76) of the patients receiving iodixanol-320 (95% confidence interval -6.2, 6.1, P = 1.0). CONCLUSION: The rate of CIN was similarly low in risk patients after intravenous administration of iopamidol-370 or iodixanol-320 for CE-MDCT.

Adult↗
PubMed2005

Efficacy and safety of MR imaging with liver-specific contrast agent: U.S. multicenter phase III study.

PURPOSE: To assess prospectively the efficacy and safety of postcontrast magnetic resonance (MR) imaging with gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) compared with that of precontrast MR imaging in patients who are known to have or are suspected of having liver lesions and who are scheduled for hepatic surgery. MATERIALS AND METHODS: Investigational review board approval and written informed consent were obtained. HIPAA went into effect after data collection. A total of 172 patients were enrolled. After precontrast MR imaging, 169 patients (94 men, 75 women; mean age, 61 years; age range, 19-84 years) received an intravenous bolus of 25 micromol/kg Gd-EOB-DTPA and underwent dynamic gradient-recalled-echo and delayed MR imaging 20 minutes after injection. Arterial and portal phase computed tomography (CT) were performed within 6 weeks of MR imaging. The standard of reference was surgery with intraoperative ultrasonography (US) and biopsy and/or pathologic evaluation of resected liver segments and/or 3-month follow-up of nonresected segments if intraoperative US was not available. Three blinded reviewers and unblinded site investigators identified liver lesions on segment maps. The Wilcoxon signed rank test was used to compare differences in per-patient sensitivity of precontrast and postcontrast MR images. Adverse events were recorded, and patient monitoring and laboratory assay were performed at time of injection and up to 24 hours after contrast material administration. RESULTS: At MR imaging, 316 lesions were identified in 131 patients. In 77% (P = .012), 72% (P = .15), and 71% (P = .027) of patients for readers 1, 2, and 3, respectively, more lesions were seen at precontrast and postcontrast MR imaging combined than at precontrast MR imaging alone. Sensitivity values for blinded readings were significantly greater at postcontrast MR imaging than at precontrast MR imaging for two of three blinded readers. For all blinded readers, combined precontrast and postcontrast MR images showed no difference in sensitivity compared with helical CT scans. The use of MR imaging, however, yielded fewer patients with at least one false-positive lesion (37%, 31%, and 34% of patients for readers 1, 2, and 3, respectively) than did helical CT (45%, 36%, and 43% of patients for readers 1, 2, and 3, respectively). CONCLUSION: Compared with precontrast MR imaging, postcontrast MR imaging with Gd-EOB-DTPA demonstrated improved sensitivity for lesion detection in the majority of blinded readers, with no substantial adverse events.

Adult↗
PubMed2005

Imaging angiogenesis: applications and potential for drug development.

Recognition of the importance of angiogenesis to tumor growth and metastasis has led to efforts to develop new drugs that are targeted to angiogenic vasculature. Clinical trials of these agents are challenging, both because there is no agreed upon method of establishing the correct dosage for drugs whose mechanism of action is not primarily cytotoxic and because of the long time it takes to determine whether such drugs have a clinical effect. Therefore, there is a need for rapid and effective biomarkers to establish drug dosage and monitor clinical response. This review addresses the potential of imaging as a way to accurately and reliably assess changes in angiogenic vasculature in response to therapy. We describe the advantages and disadvantages of several imaging modalities, including positron emission tomography, x-ray computed tomography, magnetic resonance imaging, ultrasound, and optical imaging, for imaging angiogenic vasculature. We also discuss the analytic methods used to derive blood flow, blood volume, empirical semiquantitative hemodynamic parameters, and quantitative hemodynamic parameters from pharmacokinetic modeling. We examine the validity of these methods, citing studies that test correlations between data derived from imaging and data derived from other established methods, their reproducibility, and correlations between imaging-derived hemodynamic parameters and other pathologic indicators, such as microvessel density, pathology score, and disease outcome. Finally, we discuss which imaging methods are most likely to have the sensitivity and reliability required for monitoring responses to cancer therapy and describe ways in which imaging has been used in clinical trials to date.

Angiogenesis Inhibitors↗
PubMed2005

Multidetector-row CT: economics and workflow.

With rapid evolution of multidetector-row CT (MDCT) technology and applications, several factors such as technology upgrade and turf battles for sharing cost and profitability affect MDCT workflow and economics. MDCT workflow optimization can enhance productivity and reduce unit costs as well as increase profitability, in spite of decrease in reimbursement rates. Strategies for workflow management include standardization, automation, and constant assessment of various steps involved in MDCT operations. In this review article, we describe issues related to MDCT economics and workflow.

Economics, Medical↗
PubMed2005

Imaging of acute mesenteric ischemia using multidetector CT and CT angiography in a porcine model.

Acute mesenteric ischemia, a frequently lethal disease, requires prompt diagnosis and intervention for favorable clinical outcomes. This goal remains elusive due, in part, to lack of a noninvasive and accurate imaging study. Traditional angiography is the diagnostic gold standard but is invasive and costly. Computed tomography (CT) is readily available and noninvasive but has shown variable success in diagnosing this disease. The faster scanning time of multidetector row CT (M.D.CT) greatly facilitates the use of CT angiography (CTA) in the clinical setting. We sought to determine whether M.D.CT-CTA could accurately demonstrate vascular anatomy and capture the earliest stages of mesenteric ischemia in a porcine model. Pigs underwent embolization of branches of the superior mesenteric artery, then imaging by M.D.CT-CTA with three-dimensional reconstruction protocols. After scanning, diseased bowel segments were surgically resected and pathologically examined. Multidetector row CT and CT angiography reliably defined normal and occluded mesenteric vessels in the pig. It detected early changes of ischemia including poor arterial enhancement and venous dilatation, which were seen in all ischemic animals. The radiographic findings--compared with pathologic diagnoses-- predicted ischemia, with a positive predictive value of 92%. These results indicate that M.D.CT-CTA holds great promise for the early detection necessary for successful treatment of acute mesenteric ischemia.

Acute Disease↗
PubMed2004

Distinguishing stent from stone: use of bone windows.

OBJECTIVES: To present a simple method to assist in distinguishing stents or nephrostomy tubes from urinary tract stones. Non-contrast computed tomography (CT) is now routinely used for the diagnosis and follow-up of urinary tract stones. When stents or nephrostomy tubes are in place, it may be difficult to differentiate the stent from the stone. METHODS: Three representative patients with ureteral stents or nephrostomy drainage catheters (stents/tubes) who were suspected of having residual urinary tract stones were studied by visualizing the suspicious density on CT. Abdominal windows were used for initial viewing, then bone windows were used, and the two techniques were compared. The Hounsfield units (HU) of the various stents/tubes were measured in vitro to establish reference points. The pixel densities of stones have a known range and, in our experience, may be as high as 1600 HU. RESULTS: Using the abdominal window, no difference was observed in the radiographic appearance of the stents/tubes compared with urinary calculi. However, when viewed in the bone window, the stone appeared less dense than the stent/tube. The in vitro pixel densities of the stents/tubes measured 1600 to 2600 HU compared with the calculi, which do not exceed 1600 HU. CONCLUSIONS: Using the abdominal window, stents and stones may have the same CT appearance. However, the bone window allows a visual distinction between a stent/tube and a stone. This distinction is accounted for by differences in pixel density. This observation allows one to distinguish a stent/tube from a stone on CT in patients in whom a nephrostomy tube or ureteral stent is present.

Adult↗
PubMed2004

EUS findings in patients with autoimmune pancreatitis.

BACKGROUND: Autoimmune pancreatitis is an increasingly recognized benign condition with a presentation similar to pancreatic neoplasia but responds to corticosteroid therapy. Clinical features, ERCP, and CT findings have been described. This study assessed the EUS and EUS-guided FNA features of proven autoimmune pancreatitis. METHODS: The diagnosis of autoimmune pancreatitis was based on examination of surgical resection specimens or typical clinical findings (elevated immunoglobulin G level, no evidence of malignancy, characteristic non-EUS imaging studies, and clinical improvement, especially in response to treatment with a corticosteroid). RESULTS: Presenting manifestations in 14 patients included obstructive jaundice, abdominal pain, and weight loss. Ten patients underwent surgery (including exploratory surgery). Six were successfully treated with corticosteroid. EUS revealed diffuse hypoechoic pancreatic enlargement (8/14) or a focal irregular hypoechoic mass (6/14). Features of chronic pancreatitis were not noted. EUS-guided FNA of the pancreas was suggestive of chronic inflammatory pancreatitis in 9 of 12 patients. Celiac and peripancreatic lymphadenopathy (up to 3 cm in diameter) was present in 6 patients. EUS-guided FNA of lymph nodes (3/4) did not reveal evidence of malignancy. Vascular involvement was noted in 3 patients. CONCLUSIONS: The EUS features of autoimmune pancreatitis are easily mistaken for malignancy. However, a diffusely hypoechoic, enlarged pancreas, together with chronic inflammatory cells in aspirated cytologic specimens, is supportive of the diagnosis of autoimmune pancreatitis. When combined with clinical data, EUS and EUS-guided FNA may support a diagnosis of autoimmune pancreatitis, may warrant a trial of corticosteroid, and thereby may prevent unnecessary surgery.

Adolescent↗
PubMed2002

The role of magnetic resonance cholangiopancreatography in patients with suspected biliary obstruction.

Endoscopic retrograde cholangiopancreatography (ERCP) is an accepted and accurate procedure that combines the advantage of diagnosis of biliary obstruction with possible therapeutic endobiliary intervention. However, it is an operator-dependent and invasive procedure that is associated with complications and limitations. Magnetic resonance cholangiopancreatography (MRCP) is a unique noninvasive technique for the diagnosis of biliary obstruction. It is well suited to provide the information required to plan the optimal therapeutic approach for these patients. MRCP has the potential to replace or at least precede ERCP as the first-line imaging effort in the evaluation of suspected biliary obstruction. Significant advantages and some notable limitations inherent to the modality dictate its judicious use in appropriate circumstances. The present article reviews the utility of MRCP in evaluation of biliary obstruction, with brief reference to its principles and techniques.

Adenocarcinoma↗
PubMed2002

Cystic pancreatic neoplasms evaluation by CT and magnetic resonance cholangiopancreatography.

CT provides limited assistance in the differentiation between serous and mucinous neoplasms. Because of the variability in the radiographic appearance of serous cystadenomas and overlap in CT characteristics with mucinous neoplasms, most serous neoplasms still require ancillary testing such as biopsy to reach a definitive diagnosis. MRCP is useful in differentiating benign and malignant mucinous tumors including IPMT of the pancreas. The presence of mural nodules is suggestive of malignancy; however, the absence of mural nodules does not indicate that the tumor is benign. A maximum main pancreatic duct diameter of greater than 15 mm and diffuse dilatation of the main pancreatic duct are suggestive of malignancy in main duct-type tumors. Among branch duct-type tumors, malignant tumors tend to be larger than benign tumors; however, this finding is variable. The presence of main pancreatic duct dilatation may be helpful in determining malignancy of branch duct-type tumors.

Biopsy↗
PubMed2002

Using multidetector CT for preoperative vascular evaluation of liver neoplasms: technique and results.

OBJECTIVE: The purpose of our study was to evaluate the performance of CT angiography using multidetector CT (MDCT) for preoperative vascular evaluation in candidates who were scheduled for liver neoplasm resection. SUBJECTS AND METHODS: Forty-two consecutive subjects with malignant liver tumors scheduled for resection were studied with multiphase MDCT. The first 22 subjects underwent both multiphase MDCT angiography and catheter angiography before surgery. The subsequent 20 subjects underwent only preoperative CT angiography. Postprocessing was performed, and the images were analyzed for the depiction of arterial, portal vein, and hepatic vein anatomy and for the identification of important vascular variants. The postprocessing findings were compared and correlated with the findings from catheter angiography (22/42) or intraoperative sonography (42/42) and surgery (42/42). RESULTS: Arterial anomalies were detected on the images of 17 of 42 patients, including a replaced right hepatic artery in five, replaced left hepatic artery in six, accessory right and left hepatic arteries in two, common trunk for the celiac and superior mesenteric arteries in one, and early bifurcation of the celiac artery in one. In 22 patients in whom catheter angiography confirmation was available, the number of arteries and almost all the significant anomalies were correctly identified on CT angiography (accuracy, 97%; sensitivity, 94%; specificity, 100%). In the subset of 20 patients who underwent MDCT angiography without catheter angiography confirmation, all clinically relevant information was provided by CT angiography. The portal and hepatic vein anatomy and the relationships of the liver tumors to the neighboring venous structures were shown on CT. CONCLUSION: Multidetector CT provides valuable preoperative information about hepatic vascular architecture and can be used as a noninvasive alternative to catheter angiography before oncologic liver surgery.

Adult↗
PubMedDate not supplied

Functioning acinar cell pancreatic carcinoma: diagnosis on mangafodipir trisodium (Mn-DPDP)-enhanced MRI.

We describe the imaging findings of a functional pancreatic acinar cell carcinoma in a patient who presented with weight loss, hyperlipasemia, and multiple foci of subcutaneous fat necrosis. The tumor invaded the adjacent splenic and portal vein, causing isolated left-sided portal hypertension. At MRI, the tumor showed marked enhancement following administration of the hepatobiliary-specific contrast agent mangafodipir trisodium (Mn-DPDP), thereby demonstrating the functional nature of the tumor. Avid uptake of Mn-DPDP by a functioning pancreatic tumor has not been reported in the radiology literature.

Aged↗