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Aravind Arepally

Publications and source records attributed to Aravind Arepally.

At least 19 recordsLinked to original sources
PubMed2006

Intrabiliary MR imaging: assessment of biliary obstruction with use of an intraluminal MR receiver coil.

PURPOSE: The primary aim of this study was to determine whether intrabiliary magnetic resonance (MR) imaging is feasible in a clinical setting and to optimize MR imaging parameters for the technique. In addition, it was attempted to determine the accuracy of intrabiliary MR imaging in the setting of biliary obstruction of unknown cause. MATERIALS AND METHODS: Intrabiliary MR was performed prospectively in 15 patients with biliary obstruction of unknown cause. A 0.030-inch MR intravascular receiver coil was placed in an existing biliary tube. Intrabiliary MR was performed on a 1.5-T system. T1-weighted, T2-weighted, and single-shot fast spin-echo images were acquired. T1-weighted images were also acquired after the administration of a gadolinium contrast agent. Signal intensity analysis was conducted in the region of the common bile duct. Accuracy of intrabiliary MR, computed tomography (CT), MR, and cholangiography were determined by correlation with surgical pathologic findings. RESULTS: Intrabiliary MR was successfully performed in 14 of 15 patients. MR examinations were performed in less than 1 hour. The signal-to-noise ratio in the region of the common bile duct with the intrabiliary MR technique was increased by a factor of 9 compared with standard surface-coil MR imaging (P < .00001). The mean n-plane resolution achieved was 740 +/- 20 microm x 1,150 +/- 20 microm obtained with use of a field of view of 18 cm x 18 cm (range, 15-24 cm) and a matrix of 256 x 160. Of the pulse sequences tested, the gadolinium-enhanced T1-weighted image was the best for identifying tumor and delineating tumor margins. Intrabiliary MR had a higher sensitivity than CT (100% vs 50%), a higher specificity than cholangiography (80% vs 20%), and a better correlation (P = .015) with surgical pathologic findings than CT, MR imaging, or cholangiography. CONCLUSIONS: Intrabiliary MR was well tolerated in a clinical setting and provided high spatial resolution and excellent contrast between the biliary lumen and adjacent structures. Intrabiliary MR demonstrated an advantage in detecting the presence or absence of biliary malignancies compared with currently available standard imaging techniques. The technique may be useful to evaluate biliary obstruction of unknown cause.

Cholangiography↗
PubMed2006

Evaluation of MR/fluoroscopy-guided portosystemic shunt creation in a swine model.

PURPOSE: To evaluate three different percutaneous portosystemic shunts created with magnetic resonance (MR) imaging and fluoroscopy guidance in a swine model. MATERIALS AND METHODS: In stage 1 of the experiment, an active MR intravascular needle system was created for needle tracking and extracaval punctures. Twenty inferior vena cava (IVC)/superior mesenteric vein (SMV)/portal vein (PV) punctures were performed in 10 swine (weight, 40-45 kg) in a 1.5-T short-bore interventional MR imager. With use of a real-time MR imaging sequence, the needle was guided through the IVC and into the SMV or PV (N = 20 punctures). After confirmation, a wire was advanced into the portal venous system under MR imaging guidance (N = 20). In stage 2, animals were transferred to the radiographic fluoroscopy suite for deployment of shunts. Three different shunts were evaluated in this study: (i) a commercial stent-graft, (ii) a prototype bridging stent, and (iii) a prototype nitinol vascular anastomotic device. Postprocedural necropsy was performed in all animals. RESULTS: Successful MR-guided IVC/SMV punctures were performed in all 20 procedures (100%). All three shunts were deployed. Stent-grafts had the poorest mechanism for securing a shunt. The vascular anastomotic device and the bridging stent had more secure anchoring mechanisms but also had higher technical failure rates (50% and 40%, respectively). When deployed successfully, the vascular anastomotic device resulted in no bleeding at the sites of punctures at necropsy. CONCLUSION: Percutaneous shunts and vascular anastomoses between the portal mesenteric venous system and IVC were successfully created with use of a combination of MR imaging and conventional fluoroscopy for guidance.

Alloys↗
PubMed2006

Percutaneous MR imaging-guided transvascular access of mesenteric venous system: study in swine model.

PURPOSE: To determine if, with use of magnetic resonance (MR) imaging guidance alone, transcaval puncture of the superior mesenteric vein (SMV) and/or portal vein is feasible with a percutaneous femoral vein approach. MATERIALS AND METHODS: The Institutional Animal Care and Use Committee approved the animal studies. Ten inferior vena cava (IVC)-SMV punctures were performed in six pigs. An active MR intravascular needle system was used for all transvascular punctures, and all procedures were performed with a 1.5-T MR unit. The needle was introduced via a 12-F femoral vein sheath and advanced into the IVC by using a real-time gradient-recalled-echo sequence (3.4/1.2 [repetition time msec/echo time msec], 45 degrees flip angle, and six to eight frames per second). Fast transverse spoiled gradient-recalled acquisition in the steady state (SPGR) (6.0/1.5, 60 degrees flip angle, one frame per second) was performed to confirm needle trajectory. The needle system was advanced under real-time MR imaging to puncture the SMV. The location of the needle tip was confirmed with a fast spin-echo sequence (1904/4.5, 36-cm field of view). A direct MR portogram was obtained after the administration of gadopentetate dimeglumine at a concentration of 25% with fast SPGR (6/1.3, 90 degrees flip angle, no section selection, three frames per second). Success was defined as entry into the mesenteric venous system without traversal of any retroperitoneal organs or adjacent vasculature. RESULTS: Successful MR imaging-guided IVC-SMV punctures were performed in all 10 procedures (100%). The needle was fully visualized as it traversed the retroperitoneum and entered the SMV. MR portograms were successfully obtained following all punctures through the needle. Conventional transverse MR imaging helped confirm that the needle did not traverse any retroperitoneal organs or vessels. CONCLUSION: With use of only MR imaging guidance and an active MR imaging intravascular needle system, the authors were able to successfully puncture the SMV from the IVC with direct visualization of the needle and all retroperitoneal structures.

Animals↗
PubMed2005

Magnetic resonance image-guided trans-septal puncture in a swine heart.

PURPOSE: To test the feasibility of performing magnetic resonance (MR)-guided trans-septal punctures in the swine heart. MATERIALS AND METHODS: All procedures were performed in a 1.5-T MR scanner. A novel, active MR intravascular needle system was utilized for needle tracking and septal punctures. Trans-septal punctures were performed in five swine using electrocardiogram (ECG)-gated high resolution and non-ECG-gated, real-time MR imaging techniques. The intravascular needle was advanced over a guidewire from the femoral vein. Once the needle was in proper position, trans-septal punctures were made. RESULTS: Active tracking of the needle traversing the septum was possible. The location of the catheter tip was confirmed using real time gradient recalled echo (GRE). After a confirmatory ventriculogram with gadolinium-DTPA, a 0.014-inch guidewire was advanced into the left atrium and left ventricle. All punctures were made with no change in cardiac rhythm or rate; postmortem analysis was performed on all animals and demonstrated that 18/19 (95%) punctures were directly through the fossa ovalis. CONCLUSION: Using only MR guidance and a novel active intravascular needle system, we were able to repeatedly puncture the fossa ovalis in a swine heart from a transfemoral approach, with direct visualization of all components, including the needle, the atria, the fossa ovalis, and the surrounding vasculature.

Animals↗
PubMed2005

A randomized controlled trial of beta-blockers versus endoscopic band ligation for primary prophylaxis: a large sample size is required to show a difference in bleeding rates.

Primary prophylaxis with nonselective beta-blockers in high-risk subjects has been shown to be effective in reducing both esophageal variceal bleeding and mortality. Recently it has been suggested that band ligation may be a better option for primary prophylaxis. We compared nonselective beta-blockers with band ligation in patients with large varices (F2, F3) and elevated hepatic venous wedge pressure gradient (HVWPG, > or = 12 mm Hg). All patients were prospectively followed for variceal bleeding, mortality, and treatment-related complications. Based on previous published studies, we estimated that 90 patients in each arm would be required to show a difference in bleeding rate. The study was prematurely terminated when we realized that our estimated sample size was inadequate to show a difference based on the observed bleeding rate. At the time of termination, 31 patients (Child A, 11; B, 14; C, 6), with a mean HVWPG of 19 +/- 9.1 mm Hg, were randomized to either band ligation (group A; n = 16) or beta-blockers (group B; n = 15). Baseline demographics of both groups were similar and the mean follow-up period was 27.4 +/- 12.9 months. During the follow-up, two patients in group A and one patient in group B had bleeding. Nine patients (29%; group A, six; group B, three; P = ns) died due to non-bleeding-related causes and five (16%) patients (group A, three; group B, two) underwent liver transplantation. Treatment-related complication were minimal in both groups. Despite the selection of high-risk patients, the observed bleeding rate was much lower than anticipated. Based on our observed bleeding rates, 424 patients would be required in each arm to show a difference between band ligation and beta-blocker therapy.

Adrenergic beta-Antagonists↗
PubMed2005

Intrabiliary MR imaging.

The goal of this research is to illustrate the potential role of interventional MR imaging ina clinical setting. As shown by this study, IBMR is feasible, is well tolerated, and positively affects patient management. IBMR allowed for significantly decreased field of view and high in-plane resolution and provided contrast between the biliary lumen and adjacent structures with high diagnostic accuracy. This technique enabled clinicians not only to improve imaging of the biliary tree but also to make a more accurate diagnosis. Based on this pilot work, there are several potential avenues of further expansion for IBMR. For example, enhanced imaging of the biliary tree may allow for monitoring of new biliary treatment regimens such as photodynamic therapy or molecular targeting. In addition, this technique may also foster development of innovative new percutaneous procedures that may eventually treat some biliary disorders under MR imaging guidance.

Cholestasis, Intrahepatic↗
PubMed2005

Transhepatic catheter-directed thrombectomy and thrombolysis of acute superior mesenteric venous thrombosis.

PURPOSE: To evaluate clinical outcomes after percutaneous treatment of superior mesenteric vein (SMV) thrombosis. MATERIALS AND METHODS: A retrospective chart review was conducted of all patients with SMV thrombosis treated with percutaneous catheter-directed thrombectomy/thrombolysis. The demographics of the study population, potential causative factors contributing to SMV thrombosis, and morbidity and mortality associated with therapy were assessed. RESULTS: Eleven patients (mean age, 44.3 years +/- 12.8) with SMV thrombosis were treated with percutaneous transhepatic catheter-directed thrombectomy/thrombolysis. Potential causative factors included recent major abdominal surgery, thrombophilic conditions, pancreatitis, and repetitive abdominal trauma. The mean duration between the onset of symptoms and percutaneous treatment was 8.6 days +/- 6.5. Computed tomography confirmed the clinical diagnosis in nine patients (81.8%). One patient (9.1%) had a bleeding complication, which was treated by chest tube drainage without long-term sequelae. One patient (9.1%) with refractory SMV thrombosis died of sepsis and multiple organ failure. No recurrent episode of SMV thrombosis or mortality was documented during a mean follow-up of 42 months +/- 22.5. CONCLUSIONS: Percutaneous transhepatic catheter-directed thrombectomy/thrombolysis for SMV thrombosis is associated with a rapid improvement in symptoms and low incidences of long-term morbidity and mortality. Percutaneous thrombectomy and thrombolysis should be considered in all patients with acute SMV thrombosis without evidence of bowel necrosis.

Acute Disease↗
PubMed2005

The utility of TIPS in the management of Budd-Chiari syndrome.

BACKGROUND AND AIM: Budd-Chiari syndrome (BCS) is a rare condition associated with hepatic venous outflow obstruction classically treated with portosystemic shunts or liver transplantation. Recent reports indicate promising results with the use of transjugular intrahepatic portosystemic shunts (TIPS) in the treatment of these patients. PATIENTS AND METHODS: We reviewed a 10-year single-institution experience with TIPS in patients diagnosed with BCS. RESULTS: Eleven patients with BCS underwent TIPS procedures, 3 of whom carried a diagnosis of paroxysmal nocturnal hemoglobinuria, a relative contraindication for liver transplantation. One TIPS procedure was unsuccessful for technical reasons. No patient suffered mortality or major morbidity related to the TIPS procedure. The mean reduction of portal venous pressures was 43.7%, with a mean decrease of 73% in the pressure gradient. Of the 7 patients where long-term follow-up was available, 57% had shunts which remained patent but required several nonsurgical revisions for occlusion, with an average assisted patency of 37.5 months. CONCLUSIONS: TIPS is an effective modality in the treatment of patients with BCS, especially for those who are not candidates for liver transplantation. TIPS can be successfully used as a bridge to surgical portosystemic shunting, as well as liver transplantation, but may cause technical difficulties when performing transplantation.

Budd-Chiari Syndrome↗
PubMed2005

Human peripheral arteries: feasibility of transvenous intravascular MR imaging of the arterial wall.

Feasibility of in vivo transvenous intravascular magnetic resonance (MR) imaging of the human arterial wall was determined. All subjects provided written informed consent, and institutional review board approved the study. Six arteries in six patients were imaged with a guidewire placed in the iliac vein (n = 5) or left renal vein (n = 1). Pre- and postcontrast T1-weighted and T2-weighted transvenous MR imaging were performed. An atherosclerotic plaque with a fibrous cap was identified on 27 (42%) of 64 images of veins without stents; intimal hyperplasia in a renal artery with a stent was identified on 12 images. Contrast-to-noise ratios (CNRs) on arterial wall postcontrast T1-weighted images were superior to those on images obtained with other sequences (P < .001), and the postcontrast images demonstrated the greatest number of plaques with a low-signal intensity core and fibrous cap. Preliminary results show that transvenous MR imaging is feasible for high-spatial-resolution imaging of the arterial wall and atherosclerotic plaque. Postcontrast T1-weighted imaging affords greatest CNR for the arterial wall.

Aged↗
PubMed2005

Intravascular bullet migration: a report of two cases.

In the trauma setting, penetrating vascular injuries secondary to gunshot wounds need to be addressed promptly and carefully. By identifying the entry and exit sites, the pathway of injury can usually be determined. Vessel injury is typically related to direct vascular trauma or secondary blast injury. On rare occasions, the involved vessels can serve as conduits, transporting projectiles to various locations remote from the entry wounds. The cases described demonstrate different manifestations of bullet embolism within the arterial and venous systems. We provide a literature review and we discuss therapeutic options available in these unique scenarios.

Adolescent↗
PubMed2004

Diagnostic utility and safety of transjugular kidney biopsy in the obese patient.

BACKGROUND: The obese patient may be potentially at high risk for traditional percutaneous ultrasound-guided biopsy. The utility of transjugular kidney biopsy (TJKB) in this group of patients has not been established. METHODS: We conducted a retrospective analysis of 37 obese patients who underwent TJKB at our centre. The kidney was approached via the right renal vein in 31 patients. Under fluoroscopy, core biopsies were obtained from the lower pole with a 19G biopsy needle. Post-procedure venogram was performed to assess for contrast extravasation indicating capsule perforation or communication with the collecting system. Patients were followed for procedure-related complications. Mean weight was 128 kg (range: 77-187 kg) and body mass index was 44 kg/m(2) (range: 34-64 kg/m(2)). Mean creatinine was 2.2 mg/dl (range: 0.5-6.5 mg/dl). Fifteen patients had diabetes, five of whom were nephrotic; 10 other patients had nephrotic range proteinuria. RESULTS: Of the 37 patients, six were hospitalized at the time of biopsy and three were admitted for observation. All patients returned to baseline activity the day following procedure. Histopathological diagnosis was made in 33 cases (89.2%) with a mean of 19.2 glomeruli (range: 0-62 glomeruli) per patient. There was one major complication: a delayed retroperitoneal bleed requiring multiple transfusions. Contrast extravasation outside the capsule occurred in five patients and extravasation into the collecting system occurred in three. Body mass index was not associated with number of glomeruli obtained or complication rate. CONCLUSIONS: TJKB in obese patients is a relatively safe, reliable and minimally invasive procedure with an excellent diagnostic yield.

Adolescent↗
PubMed2004

Incidence of venous obstruction following insertion of an implantable cardioverter defibrillator. A study of systematic contrast venography on patients presenting for their first elective ICD generator replacement.

AIMS: The number of implantable cardioverter defibrillator (ICD) implantations, as well as follow-up procedures such as generator exchanges, lead revisions and lead system upgrades, is ever-increasing. Lead revisions and implantation of additional leads require venous access at the site of the previous ICD implantation. The aim of our study was therefore to evaluate the incidence of venous obstruction after chronic transvenous ICD system implantation. METHODS AND RESULTS: One hundred and five consecutive patients admitted for their first elective ICD generator replacement were included. All patients underwent bilateral contrast venography and the images were analyzed by two attending radiologists. Venous obstruction was classified as moderate stenosis (50-75% diameter reduction), severe stenosis (>75%) or total occlusion. Venous obstruction of various degrees was found in 25% of the patients. Complete occlusion was found in 9%, severe stenosis in 6% and moderate stenosis in 10% of the patients. The incidence of venous obstruction was increased in patients with a pacemaker prior to the initial ICD system implantation (67%). No difference was found in patients with a single defibrillator lead compared with patients who had an additional superior vena cava (SVC) shocking coil. However, the presence of a second shocking coil in the SVC incorporated in a single ICD lead was associated with an increased incidence of venous obstruction. No difference was found between silicone and polyurethane insulated leads. CONCLUSION: This study shows that venous obstruction occurs relatively frequently after ICD implantation. Therefore, contrast venography should always be obtained if malfunction of a preexistent lead is suspected or a system upgrade is considered.

Brachiocephalic Veins↗
PubMed2004

Safety and hemodynamic effects of pulmonary angiography in patients with pulmonary hypertension: 10-year single-center experience.

OBJECTIVE: We sought to examine the incidence of complications and change in pulmonary artery pressure in patients with pulmonary hypertension who were undergoing pulmonary angiography. MATERIALS AND METHODS: A retrospective review was performed for all patients who underwent pulmonary angiography over a 10-year period at a single institution. Patients with moderate pulmonary hypertension (pulmonary artery pressure, 30-59 mm Hg) and severe pulmonary hypertension (pulmonary artery pressure, >/= 60 mm Hg) served as the study population. Demographic data, clinical indication, pre- and postcontrast pulmonary artery pressure measurements, type of pulmonary hypertension, contrast agent volume, complications, and American Society of Anesthesiologists (ASA) classification were recorded for all patients and compared. RESULTS: Two hundred two of 612 patients who underwent pulmonary angiography had pulmonary hypertension. Moderate pulmonary hypertension was present in 155 patients (77%) and severe pulmonary hypertension, in 47 patients (23%). Three (2.0%) of four complications were fatal. The complication rate was higher in patients with severe pulmonary hypertension compared with patients with moderate pulmonary hypertension but not statistically significant (6.3% vs 0.6%, p = 0.63). Patients with complications had a higher mean ASA score than those without complications (4.0 vs 3.0, p = 0.03). Patients with lung transplants had the greatest increase in pulmonary artery pressure after pulmonary angiography compared with all other clinical indications (16.75 +/- 12.97 mm Hg vs 5.46 +/- 6.86 mm Hg, p = 0.003). CONCLUSION: The complication rate of pulmonary angiography in patients with pulmonary hypertension is low. However, in severely ill patients with acute pulmonary hypertension, pulmonary angiography should be undertaken with extreme caution.

Angiography↗
PubMed2003

Spontaneous renal artery dissection: treatment with coil embolization.

A 47-year-old man presented with nonspecific left flank pain and severe hypertension as a result of a spontaneous dissection of an accessory renal artery. Because of the progressive increase in the size of the dissection flap and uncontrollable hypertension, treatment with segmental embolization of the true and false lumen of the accessory renal artery was performed with successful clinical outcome. This case report will address the salient clinical features of spontaneous renal artery dissections and treatment options.

Aortic Dissection↗
PubMed2003

Arteriographic and pathologic evaluation of two suture-mediated arterial closure devices in a porcine model.

PURPOSE: To determine the acute and short-term effects the Sutura 8-F SuperStitch and Perclose 6-F Closer devices have on the femoral artery, as determined by angiography and pathologic examination. MATERIALS AND METHODS: From a common carotid artery cutdown, eight pigs underwent pelvic angiography (i) before placement of bilateral common femoral artery vascular sheaths, (ii) after sheath insertion, and (iii) after device deployment. Two pigs were immediately killed; six survived 4 weeks for repeat angiography and vessel harvest. RESULTS: Average vessel diameter before sheath insertion was 5.9 mm +/- 0.6 and 5.8 mm +/- 0.6 for vessels with Perclose and Sutura devices, respectively. After deployment of the Sutura device, there was a 44.7% (P =.001) mean diameter reduction from preprocedural diameters, compared to a 59.3% reduction (P <.001) with the Perclose device. After deployment of the Sutura device, there was a mean vessel diameter reduction of 14.1% (P =.53) versus the diameter immediately after sheath placement. After deployment of the Perclose device, there was a mean vessel diameter reduction of 43.8% (P =.05) versus the diameter immediately after sheath placement. At 4-week angiography, all vessels returned to their original diameters before sheath insertion. Pathologic examination showed mild adventitial fibrosis creating a "fibrous hood" surrounding the suture and vessel. CONCLUSIONS: Despite significant luminal compromise after device deployment, all vessels appeared normal on angiography at 4 weeks. Contrary to the normal angiographic findings, both devices incited periadventitial fibrosis, which created a fibrous hood around the suture and vessel.

Angiography↗
PubMed2003

Transcatheter coil embolization of large pulmonary artery pseudoaneurysms in a child.

The authors report a case of a 5-year-old boy who initially presented with mastoiditis, underwent successful surgical treatment, and during the immediate postoperative period developed multiple, bilateral pulmonary artery pseudoaneurysms. The large size and multiplicity of the pseudoaneurysms precluded the patient from undergoing thoracic surgery. Successful endovascular coil and wire embolization was performed in a staged set of procedures with use of more than 30 m of wire and coils.

Aneurysm, False↗
PubMed2003

In vivo intravascular MR imaging: transvenous technique for arterial wall imaging.

PURPOSE: To determine, in vivo, the potential for transvenous magnetic resonance (MR) imaging of the arterial wall and to assess appropriate MR pulse sequences for this method. MATERIALS AND METHODS: MR imaging was performed on 19 vessels (right renal artery, N = 9; left renal artery N = 2; external iliac artery, N = 4; abdominal aorta, N = 4) in nine swine. The animals were either low-density lipoprotein receptor knockout (N = 5) or Yucatan mini-pigs fed an atherogenic diet for 6 to 11 weeks (N = 4). The intravascular MR coil/guide wire (IVMRG) (Surgi-Vision, Gaithersburg, MD) was introduced via the external iliac vein into the inferior vena cava (IVC). The following electrocardiograph-gated MR pulse sequences were obtained: T1-weighted precontrast with and without fat saturation and T1-weighted postcontrast with fat saturation. Two observers scored wall signal and conspicuity and classified the vessel as normal, abnormal, or stented. Images were compared with histopathologic findings. RESULTS: The T1-weighted precontrast without fat saturation, T1-weighted precontrast with fat saturation, and T1-weighted postcontrast images correlated with histopathologic findings in 12 of 15 vessels, eight of 10 vessels, and 14 of 16 vessels, respectively. Abnormal histopathologic findings included: arterial wall thickening (N = 3), arterial dissection (N = 2), focal fibrous plaque (N = 2), adherent thrombus (N = 1). The T1-weighted postcontrast images were not compromised by artifacts and had the highest score for vessel wall signal and conspicuity. T1-weighted precontrast images were compromised by chemical shift artifact and poor blood suppression. Negligible artifacts were created by the platinum stent. CONCLUSION: The T1-weighted fat saturated postcontrast pulse sequence was superior to other sequences for transvenous MR imaging of the arterial wall.

Animals↗