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Sanjeeva P Kalva

Publications and source records attributed to Sanjeeva P Kalva.

16 recordsLinked to original sources
PubMed2007

16-MDCT angiography in living kidney donors at various tube potentials: impact on image quality and radiation dose.

OBJECTIVE: The objective of our study was to compare the performance of 16-MDCT angiography at various peak kilovoltage (kVp) settings and the impact of the different settings on image quality and on radiation dose in adult kidney donors. MATERIALS AND METHODS: Sixty-two renal donors (32 men, 30 women) who underwent 16-MDCT were divided into three groups: 18 subjects were studied at 140 kVp (group A); 20, at 120 kVp (group B); and 24, at 100 kVp (group C). Other constant scanning parameters were as follows: detector collimation, 0.625 mm; table feed, 9.375 mm/rotation; gantry rotation time, 500 milliseconds; and automatic current tube modulation (ATCM) using a noise index of 15. A total of 135-140 mL of iodinated contrast material (300 mg I/mL) was administered at 5 mL/s via an 18-gauge cannula, and arterial phase scanning was initiated using a bolus-tracking technique. Two observers evaluated image quality of the axial and 3D images and the visibility of branch order in the superior mesenteric artery (SMA) and renal arteries. Attenuation (in Hounsfield units [H]) in the aorta, SMA, and main renal artery was also measured by placing a region of interest. Radiation dose measurements were based on the scanner-generated CT dose index volume (CTDI(vol)). Each parameter tested was compared among the three groups using a nonparametric analysis of variance test, and a p value of 0.05 was considered significant. RESULTS: Differences in the quality of the axial images existed between groups A and C (p < 0.001) and between groups B and C (p < 0.01); the image quality of the 3D images and the visibility of branch order in the SMA and renal arteries were comparable for all groups. The difference in mean attenuation of the aorta, SMA, and renal arteries was significant between groups A and C (p < 0.001) and between groups B and C (p < 0.01). All groups had 100% diagnostic accuracy in identifying the number of renal arteries on the side of nephrectomy. The mean radiation dose in CTDI(vol) was 25 +/- 3 mGy at 140 kVp, 17 +/- 4 mGy at 120 kVp, and 12 +/- 3 mGy at 100 kVp (p < 0.001). CONCLUSION: Our initial observations suggest that the image quality of 16-MDCT angiography performed at 120 kVp is similar to that of CT angiography (CTA) performed at 140 kVp in adult kidney donors but with a significant radiation dose reduction. CTA at 100 kVp results in higher image noise but provides diagnostically acceptable images with significant radiation dose reduction compared with CTA at 120 or 140 kVp.

Adult↗
PubMed2006

Mediastinal bronchial artery aneurysms: endovascular therapy in two patients.

We report two patients with cystic fibrosis and mediastinal bronchial artery aneurysms treated by means of endovascular coil embolization. In one case, the presence of a long segment of bronchial artery proximal to the aneurysm allowed coil embolization with regular steel coils. In the second case, the aneurysm was near the origin of the bronchial artery from the aorta. We used detachable coils to occlude this aneurysm for more precise embolization.

Adult↗
PubMed2006

TrapEase vena cava filter: experience in 751 patients.

PURPOSE: To evaluate the clinical safety and efficacy of the TrapEase vena cava filter in a 4-year single-center experience. METHODS: The clinical and imaging data of 751 patients (384 men; mean age 64 years, range 16-99) who had a TrapEase inferior vena cava (IVC) filter placed between January 1, 2001, and December 31, 2004, were reviewed retrospectively. More than a third of patients (297, 39.5%) presented with pulmonary embolism (PE), 188 (25.0%) had deep vein thrombosis (DVT), 40 (5.3%) had both PE and DVT, and the rest (226, 30.1%) had other symptoms. Indications for filter placement were contraindication to anticoagulation (461, 61.4%), complication of anticoagulation (42, 5.6%), failure of anticoagulation (39, 5.2%), and prophylaxis (209, 27.8%). Filters were placed in the infrarenal (n=738) or suprarenal (n=13) position through a femoral (n=729) or jugular vein (n=22) approach. Follow-up computed tomographic (CT) scans of the chest and abdomen were evaluated for recurrent PE and filter-related complications, respectively. RESULTS: Three (0.4%) patients developed groin hematoma. During a mean 295-day clinical follow-up (range 1-1677), 55 (7.5%) patients developed symptoms of PE, and 1 (0.1%) death was attributed to PE. Chest CT performed for various clinical indications in 219 patients at a mean 192 days (range 1-1346) showed PE in 15 (6.8%) patients; 10 were symptomatic and 5 asymptomatic, but there were no fatalities. Follow-up abdominal CT (n=270) at a mean 189 days (range 1-1415) showed fracture of filter components in 8 (3.0%), thrombus within the filter in 68 (25.2%), thrombus extending beyond the filter in 4 (1.5%), near total caval occlusion in 2 (0.7%), and no cases of migration. CONCLUSION: The TrapEase vena cava filter is effective in the prevention of pulmonary embolism, with minimal complications.

Adolescent↗
PubMed2005

Multi-detector row CT in evaluation of 94 living renal donors by readers with varied experience.

PURPOSE: To retrospectively assess the accuracy of four-section multi-detector row computed tomography (CT) in the evaluation of renal transplant donors when scans are read by one of multiple readers with varied levels of expertise, by using surgery as the reference standard. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board and complied with the Health Insurance Portability and Accountability Act. Informed consent was waived. Between October 1999 and March 2003, 94 renal donors (42 men, 52 women; mean age, 44 years) underwent four-section multi-detector row CT. Unenhanced scanning of the abdomen was performed with 5-mm section thickness and table speed of 15 mm per rotation. Next, 135-150 mL of nonionic iodinated (300 mg/mL) contrast material was injected intravenously at a rate of 4-5 mL/sec. Contrast material-enhanced CT was initiated 20-25 seconds, 65-70 seconds, and 10 minutes after start of injection. Arterial phase scanning was performed with 1.25-mm section thickness and 7.5-mm table speed. Venous and excretory phase scanning was performed with 2.5-mm section thickness and 15-mm table speed. Each scan was evaluated independently by one of 11 readers for renal vascular and ureteral anatomic variants. Findings at CT were compared with those at surgery. Sensitivity and specificity (with 95% confidence intervals) and accuracy of CT were calculated on the basis of presence or absence of variant anatomy at surgery. RESULTS: CT depicted 107 of 114 renal arteries confirmed at surgery; seven accessory arteries were missed in six donor kidneys. CT depicted 95 of 98 renal veins confirmed at surgery. Sensitivity and specificity of CT were 66% and 100%, 75% and 100%, and 50% and 100%, and overall accuracy was 94%, 97%, and 99%, for identification of variant anatomy of renal arteries, veins, and ureters, respectively. CONCLUSION: Multi-detector row CT as the sole imaging technique in the preoperative evaluation of living renal donors is accurate even when images are read by multiple readers with varied levels of expertise.

Adult↗
PubMed2005

Assessing tumor perfusion and treatment response in rectal cancer with multisection CT: initial observations.

PURPOSE: To use first-pass perfusion computed tomography (CT) to prospectively investigate tumor vascularity in rectal cancer and to determine whether any of the perfusion parameters would predict tumor response to chemotherapy and radiation therapy. MATERIALS AND METHODS: The institutional review board approved this study, and informed prior consent was obtained from participants. Perfusion CT of rectal cancer was performed with four-section multi-detector row CT in 15 patients (13 men, two women; mean age, 62.1 years; age range, 46-84 years). Five patients with prostate cancer served as controls. All patients with rectal cancer underwent 6-8 weeks of chemotherapy and radiation therapy followed by surgery. In nine patients, perfusion CT was repeated after completion of chemotherapy and radiation therapy. Contrast medium-enhanced dynamic CT was performed with a static table position for 45 seconds, and the data were analyzed by using commercial software to calculate tissue blood flow (BF), blood volume, mean transit time (MTT), and vascular permeability-surface area product. Perfusion parameters of normal rectum and tumor were compared. Perfusion parameters before and after chemotherapy and radiation therapy were compared. A tumor was considered to have responded if its stage at pathologic analysis indicated regression compared with the preoperative stage. Baseline perfusion values were compared between responders and nonresponders. Statistical analysis was performed with the Student t test. RESULTS: Rectal cancer showed higher BF and shorter MTT compared with those of normal rectum (P < or =.05). After chemotherapy and radiation therapy, tumors showed significant reduction in BF and increase in MTT (P < or =.05). There was a significant difference in baseline BF and MTT values between responders and nonresponders (P < or =.05). Tumors in three patients with high initial BF and short MTT showed poor response. CONCLUSION: Perfusion CT of rectal cancer can enable assessment of tumor vascularity and perfusion changes that result from chemotherapy and radiation therapy. In this small patient sample, tumors with initial high BF and short MTT values tended to respond poorly to chemotherapy and radiation therapy.

Aged↗
PubMed2005

Detection of liver metastases from adenocarcinoma of the colon and pancreas: comparison of mangafodipir trisodium-enhanced liver MRI and whole-body FDG PET.

OBJECTIVE: The objective of our study was to assess the relative performance of mangafodipir trisodium-enhanced liver MRI and whole-body FDG PET for the detection of liver metastases from adenocarcinoma of the colon and pancreas. MATERIALS AND METHODS: Imaging data of 34 patients (23 men, 11 women; age range, 44-78 years) with adenocarcinoma of the colon (n = 27) or adenocarcinoma of the pancreas (n = 7) who had undergone mangafodipir trisodium-enhanced liver MRI and whole-body FDG PET were retrospectively reviewed for the presence and number of liver metastases. Histopathology (n = 25) or follow-up imaging (n = 9) served as the standard of reference. Breath-hold T1-weighted gradient-recalled echo, respiratory-triggered T2-weighted fast spin-echo, and mangafodipir trisodium-enhanced axial fat-saturated high-spatial-resolution (256 x 512) T1-weighted gradient-recalled echo images were obtained on a 1.5-T scanner. FDG PET was performed after the injection of 15-20 mCi (555-740 MBq) of FDG. The sensitivity, positive predictive value, and accuracy were calculated for each technique. The performances of the two techniques were compared using the Fisher's exact test. RESULTS: Thirty patients had hepatic metastases and four had no hepatic metastases according to the standard of reference. The total number of metastases was 79, including 33 that measured less than 1 cm. Based on a per-patient analysis, MRI and FDG PET showed sensitivities of 96.6% and 93.3%, positive predictive values of 100% and 90.3%, and accuracies of 97.1% and 85.3%, respectively. According to a per-lesion analysis, MRI and FDG PET showed sensitivities of 81.4% and 67.0%, positive predictive values of 89.8% and 81.3%, and accuracies of 75.5% and 64.1%, respectively. MRI detected more hepatic metastases than FDG PET (p = 0.016). Of the 33 subcentimeter lesions confirmed on the standard of reference, all were identified on MRI, whereas only 12 were detected on FDG PET (p = 0.0001). CONCLUSION: In patients with colon and pancreatic adenocarcinoma, high-spatial-resolution mangafodipir trisodium-enhanced liver MRI and whole-body FDG PET were comparable in the detection of patients with liver metastases. FDG PET provided additional information about extrahepatic disease and was useful in initial staging. However, significantly more and smaller liver metastases were detected on MRI than on FDG PET.

Adenocarcinoma↗
PubMed2004

Autoimmune pancreatitis: imaging features.

PURPOSE: To retrospectively determine imaging findings in patients with autoimmune pancreatitis. MATERIALS AND METHODS: Twenty-nine patients (25 male and four female; mean age, 56 years; range, 15-82 years) with histopathologic diagnosis of autoimmune pancreatitis were examined. Data were reviewed by two radiologists in consensus. Imaging findings for review included those from helical computed tomography (CT), 25 patients; magnetic resonance (MR) imaging with MR cholangiopancreatography (MRCP), four patients; endoscopic ultrasonography (US), 21 patients; endoscopic retrograde cholangiopancreatography (ERCP), 19 patients; and percutaneous transhepatic cholangiography, one patient. Images were analyzed for appearances of pancreas, biliary and pancreatic ducts, and other findings, such as peripancreatic inflammation, encasement of vessels, mass effect, pancreatic calcification, peripancreatic nodes, and peripancreatic fluid collection. Follow-up images were available in nine patients. Serologic markers such as serum immunoglobulin G (IgG) and antinuclear antibody levels were available in 12 patients. RESULTS: CT showed diffuse (n = 14) and focal (n = 7) enlargement of pancreas. Seven patients had minimal peripancreatic stranding, with lack of vascular encasement, calcification, or peripancreatic fluid collection. Nine patients had enlarged peripancreatic lymph nodes. MR imaging showed focal (n = 2) and diffuse (n = 2) enlargement with rimlike enhancement in one. MRCP revealed pancreatic duct strictures in two and sclerosing cholangitis-like appearance in one. Endoscopic US showed diffuse enlargement of pancreas with altered echotexture in 13 patients and focal mass in the head in six. ERCP showed stricture of distal common bile duct in 12 patients, irregular narrowing of intrahepatic ducts in six, diffuse irregular narrowing of pancreatic duct in nine, and focal stricture of proximal pancreatic duct in six. Serologic markers showed increased IgG and antinuclear antibody levels in seven of 12 patients. At follow-up, CT abnormalities and common bile duct strictures resolved after steroid therapy in three patients. CONCLUSION: Features that suggest autoimmune pancreatitis include focal or diffuse pancreatic enlargement, with minimal peripancreatic inflammation and absence of vascular encasement or calcification at CT and endoscopic US, and diffuse irregular narrowing of main pancreatic duct, with associated multiple biliary strictures at ERCP.

Adolescent↗
PubMed2004

Intraoperative US in patients undergoing surgery for liver neoplasms: comparison with MR imaging.

PURPOSE: To retrospectively compare intraoperative ultrasonography (US) and preoperative magnetic resonance (MR) imaging with contrast material enhancement for the depiction of liver lesions in patients undergoing hepatic resection. MATERIALS AND METHODS: A radiologist (D.V.S.) and a surgeon (K.K.T.) retrospectively identified 79 patients (36 female and 43 male patients; age range, 10-78 years; mean age, 57 years) who had undergone surgical resection for primary liver tumor or metastasis and had also undergone preoperative contrast-enhanced MR imaging within 6 weeks before surgery. MR imaging was performed with a 1.5-T system. Dedicated intraoperative US of the liver was performed or supervised by a gastrointestinal radiologist using a 7.5-MHz linear-array transducer, after adequate hepatic mobilization by the surgeon. Histopathologic evaluation of the 159 resected hepatic lesions served as the reference standard. The lesion distribution included colon cancer metastasis (n = 122), hepatocellular carcinoma (n = 23), cholangiocarcinoma (n = 6), cavernous hemangioma (n = 4), focal nodular hyperplasia (n = 2), hamartoma (n = 1), and metastatic embryonal sarcoma (n = 1). RESULTS: Of 159 lesions, 138 (86.7%) were identified at both MR imaging and intraoperative US. Twelve additional lesions (7.5%) in 10 patients were detected only at intraoperative US (eight metastases, one hepatocellular carcinoma, one cholangiocarcinoma, one hemangioma, and one biliary hamartoma). Both modalities failed to depict nine lesions (5.6%) (four metastases, four hepatocellular carcinomas, and one cholangiocarcinoma). The sensitivities of MR imaging and intraoperative US for liver lesion depiction were 86.7% and 94.3%, respectively. Surgical management was altered on the basis of the intraoperative US findings in only three of 10 patients (4%). CONCLUSION: Contrast-enhanced MR imaging is as sensitive as intraoperative US in depicting liver lesions before hepatic resection.

Adolescent↗
PubMed2004

Direct evidence that the VEGF-specific antibody bevacizumab has antivascular effects in human rectal cancer.

The effects of vascular endothelial growth factor (VEGF) blockade on the vascular biology of human tumors are not known. Here we show here that a single infusion of the VEGF-specific antibody bevacizumab decreases tumor perfusion, vascular volume, microvascular density, interstitial fluid pressure and the number of viable, circulating endothelial and progenitor cells, and increases the fraction of vessels with pericyte coverage in rectal carcinoma patients. These data indicate that VEGF blockade has a direct and rapid antivascular effect in human tumors.

Adenocarcinoma↗
PubMed2004

Imaging the liver.

Imaging of the liver is undertaken for the detection and characterization of suspected primary or secondary neoplasms, prior to planning a surgery or chemotherapy pump placement, for assessing treatment response, for evaluating biliary pathology, and for screening for liver neoplasms in high-risk groups. In this article, we review the advantages and disadvantages of various imaging modalities in the evaluation of the liver and formulate guidelines for the imaging of common clinical indications. A brief review of imaging findings in focal and diffuse liver disease is also presented.

Diagnostic Imaging↗
PubMed2003

Imaging of rectal cancer.

Radiologic evaluation of rectal cancer is invaluable in aiding the surgeon, gastroenterologist, and oncologist in the initial and follow-up management of patients with this malignancy. This review highlights recent developments in computed tomography; ultrasonographic, metabolic, and magnetic resonance imaging of rectal cancer; its clinical ramifications; and the direction of future efforts.

Endosonography↗
PubMedDate not supplied

"Recovery" vena cava filter: experience in 96 patients.

The purpose of the study was to assess the clinical safety and efficacy of the "Recovery(TM)" (Bard) inferior vena cava (IVC) filter. We retrospectively evaluated the clinical and imaging data of patients who had a "Recovery(TM)" IVC filter placed between January 2003 and December 2004 in our institution. The clinical presentation, indications, and procedure-related complications during placement and retrieval were evaluated. Follow-up computed tomography (CT) examinations of the abdomen and chest were evaluated for filter-related complications and pulmonary embolism (PE), respectively. "Recovery" filters were placed in 96 patients (72 males and 24 females; age range: 16-87 years; mean: 46 years). Twenty-four patients presented with PE, 13 with deep vein thrombosis (DVT) and 2 with both PE and DVT. The remaining 57 patients had no symptoms of thromboembolism. Indications for filter placement included contraindication to anticoagulation (n = 27), complication of anticoagulation (n = 3), failure of anticoagulation (n = 5), and prophylaxis (n = 61). The device was successfully deployed in the infrarenal (n = 95) or suprarenal (n = 1) IVC through a femoral vein approach. Retrieval was attempted in 11 patients after a mean period of 117 days (range: 24-426). The filter was successfully removed in nine patients (82%). Failure of retrieval was due to technical difficulty (n = 1) and the presence of thrombus in the filter (n = 1). One of the nine patients who had the filter removed developed IVC thrombus after retrieval and another had an intimal tear of the IVC. Follow-up abdominal CT (n = 40) at a mean of 80 days (range: 1-513) showed penetration of the IVC by the filter arms in 11, of which 3 had fracture of filter components. In one patient, a broken arm migrated into the pancreas. Asymmetric deployment of the filter legs was seen in 12 patients and thrombus within the filter in 2 patients. No filter migration or caval occlusion was encountered. Follow-up chest CT (n = 27) at a mean of 63 days (range: 1-386) showed PE in one patient (3%). During clinical follow-up, 12 of 96 patients developed symptoms of PE and only 1 of the 12 had PE on CT. There was no fatal pulmonary embolism in our group of patients following "Recovery" filter placement. However, the current version of the filter is associated with structure weakness, a high incidence of IVC wall penetration, and asymmetric deployment of the filter legs.

Adolescent↗
PubMedDate not supplied

Leiomyosarcoma of the uterus with intravascular tumor extension and pulmonary tumor embolism.

We report the case of a 48-year-old woman presenting with recurrent uterine leiomyosarcoma (LMS) associated with right iliac vein and inferior vena cava (IVC) invasion and left lower lobe pulmonary tumor embolus. Because the prognosis and treatment differ from that of thrombotic pulmonary emboli, the differentiating imaging characteristics of intravascular tumor embolism are reviewed. To our knowledge, only two other cases of intravenous uterine leiomyosarcomatosis have been described in the existing literature, and this is the first reported case of the entity with associated intravascular tumor embolism.

Diagnosis, Differential↗
PubMedDate not supplied

Using the K-edge to improve contrast conspicuity and to lower radiation dose with a 16-MDCT: a phantom and human study.

PURPOSE: To study the effect of tube current (milliamperes; mA) and potential (peak kilovolt; kVp) on the attenuation values and contrast-to-noise ratios of iodine- and gadolinium-based contrast media (CM) for computed tomography angiography (CTA). MATERIALS AND METHODS: Phantom Study: A water-filled phantom with five 20-mL syringes filled with 1:20 dilution of 282, 300, 370, and 400 milligrams of iodine per milliliter concentration CM and gadopentetate dimeglumine (Magnevist, Berlex Laboratories, Wayne, NJ, 0.5 mol/L) was scanned with a 16-multidetector CT using 80, 100, 120, and 140 kVp and 500-millisecond gantry rotation time. The milliampere was either fixed at 100, 200, 300, and 380 or automatically adjusted with noise indices of 15, 20, and 25 or manually adjusted to maintain a constant image noise. The attenuation value (Hounsfield unit; HU) and its standard deviation of CM in each syringe and of the water phantom were obtained. Statistical analysis was performed to determine difference between attenuation values and contrast medium-to-water contrast-to-noise ratios at various kVp and mA selection. Human Study: Three groups of patients had CTA for abdominal aortic aneurysm with similar computed tomography parameters, varying only in kVp selection of either 100 (group A), 120 (group B), or 140 (group C). Another group (group D) had CTA at 100 kVp but with the CM volume reduced to 60%. The CTA studies were evaluated for the quality of axial and 3D images; attenuation values in the aorta, superior mesenteric artery, and iliac arteries; image noise; and scanner-estimated radiation dose. Statistical analysis was performed to determine the difference in image quality and radiation dose among the groups. RESULTS: Phantom Study: In comparison with 140 kVp, regardless of selected milliampere or noise indices, images acquired at 80, 100, and 120 kVp showed 90.8% to 94.2%, 47% to 49.7%, and 18.9% to 20.7% (P<0.0001) increase in HU of iodine-based CM, respectively, and 62.9%, 39.6%, and 16.8% (P<0.0001) increase in HU of gadolinium-based CM, respectively. Human Study: The axial images in all the groups were diagnostically acceptable. There was significantly inferior quality of axial images associated with greater image noise in group A and group D (P<0.01) in comparison with group C, but there was no difference in the quality of 3D images among the 4 groups. In comparison with group C, there was significantly higher attenuation of the aorta, superior mesenteric artery, and iliac arteries in group A (P<0.01), group B (P<0.05), and group D (P<0.01). The radiation dose (CT dose index volume) decreased to 12+/-4 in groups A and D compared with 17+/-4 in group B and 24+/-5 in group C. CONCLUSIONS: Lower kVp increases the attenuation of iodinated and gadolinium CM. CTA of the abdominal aorta performed at low kVp results in higher attenuation in aorta with reduced radiation dose and without degrading the diagnostic image quality. The iodinated CM volume can be reduced by reducing kVp during CTA.

Adolescent↗