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J B Karani

Publications and source records attributed to J B Karani.

15 recordsLinked to original sources
PubMed2006

Parametric mapping of the hepatic perfusion index with gadolinium-enhanced volumetric MRI.

The purpose of this study was to adapt the hepatic perfusion index (HPI) methodology previously developed for MRI to derive 3D parametric maps of HPI, and to investigate apparent differences in HPI maps between a group of colorectal cancer patients and controls. To achieve this, a new and simpler approach to HPI calculation which does not require measurements from the aorta or portal vein is introduced, and assessed with large liver regions of interest (ROIs) in patients and controls. Several example HPI maps showing localized variation are then presented. The subject group consisted of 12 patients with known colorectal metastases, and 13 control subjects referred for routine contrast-enhanced spine imaging with no history of neoplastic disease. HPI was evaluated from serial T1 volume acquisitions acquired over the course of a Gd-DTPA bolus injection. Regions of abnormal perfusion were visible on the HPI maps derived for the patient group, manifested as areas of locally increased HPI extending around the visible margins of known metastases evident on the conventional contrast-enhanced images. This method for MR voxel-based parametric mapping of HPI has the potential to demonstrate regional variations in perfusion at the segmental and subsegmental level.

Adult↗
PubMed2005

Comparison of the hepatic perfusion index measured with gadolinium-enhanced volumetric MRI in controls and in patients with colorectal cancer.

The aim of the study was to adapt the methodology established for dynamic CT measurements of the hepatic perfusion index (HPI) to MRI, and to assess the potential role of MRI measurements of the HPI in detecting regional alterations in liver perfusion between patients with colorectal liver metastases and normal controls. The HPI was evaluated from serial T(1) volume acquisitions acquired over the course of a Gd-DTPA bolus injection. Time-course data from regions of interest in the liver, spleen and aorta were used to calculate the HPI; and HPI data from control subjects were compared with data from patients with known colorectal metastases. Significant differences were found between the relative portal perfusion and hepatic perfusion indices calculated for the patient and control groups (p<0.005). These results suggest that hepatic perfusion indices can be derived using MRI-based methods, and that these perfusion indices are sensitive to differences in liver perfusion associated with established metastatic liver disease on imaging. This technique may contribute to the early detection of liver metastases, allowing early surgical intervention and improved patient survival.

Adult↗
PubMed2002

Hepatic artery stenosis following liver transplantation: significance of the tardus parvus waveform and the role of microbubble contrast media in the detection of a focal stenosis.

PURPOSE: To evaluate the role of microbubble ultrasound contrast media in detecting stenosis of the post-liver transplant extrahepatic hepatic artery (HA) in the presence of the tardus parvus spectral Doppler waveform of the intrahepatic HA. MATERIALS AND METHODS: All post-liver transplant patients with a prolonged systolic acceleration time (SAT>0.08s) and/or a reduced resistant index (RI<0.50) of the HA (the tardus parvus waveform) on colour Doppler ultrasound (CDUS), were assessed with microbubble contrast medium for a focal arterial stenosis. Following microbubble contrast-enhanced CDUS, patients underwent arteriography or follow-up CDUS. RESULTS: A total of 2038 examinations were performed in 529 liver transplant recipients; 16 (3.02%) tardus parvus waveforms were identified. The median SAT of the intrahepatic HA was 0.18s (range 0.11-0.38s) and the RI 0.47 (range 0.22-0.58). No extrahepatic elevated peak systolic velocity (PSV), defined as above 1.00m/s, was detected on the baseline examinations. Following the administration of microbubble contrast, medium, PSV in the extrahepatic HA was elevated in 14 of 16 patients, (median=2.15m/s, range=1.44-3.10m/s); flow was not identified in two patients. Arteriography was performed in 10 patients and confirmed stenosis in eight (median grade of stenosis 93%, range 60-99%) and occlusion in two. The measured median PSV at contrast-enhanced CDUS in the stenosis group was 2.03m/sec (range 1.44-2.71m/sec). Repeat CDUS in six patients not undergoing arteriography showed resolution in four; one underwent re-transplantation before arteriography and one patient maintains a tardus parvus waveform. In transplant recipients undergoing arteriography during the study period (n=55), no hepatic artery stenosis without a tardus parvus waveform was seen. CONCLUSION: The tardus parvus waveform pattern is an excellent screening test for the presence of post-liver transplantation hepatic artery stenosis. There is only a limited role for microbubble ultrasound contrast agent in the presence of a tardus parvus waveform. It could be used following equivocal colour Doppler ultrasound, but arteriography will still be necessary.

Adolescent↗
PubMed2001

Survival and outcome after hepatic artery thrombosis complicating pediatric liver transplantation.

BACKGROUND/PURPOSE: Hepatic artery thrombosis (HAT) represents a significant cause of graft loss and mortality after pediatric orthotopic liver transplantation (OLT). The incidence and etiology of this complication have been investigated in detail but relatively little is known about outcome. METHODS: A review was conducted of all children with confirmed HAT complicating OLT during a 10-year period (1990 through 1999) in a single center. HAT was established by angiography or at operation in all cases. RESULTS: From a consecutive series of 400 pediatric OLTs, there were 31 (7.8%) instances of HAT in 29 children of median age 3.8 years (range, 8 days to 16 years). Twenty-four (83%) are alive after a median follow-up of 3.6 years. Fourteen cases occurred after transplantation of whole grafts and 17 after reduced or split livers. Of the 18 episodes resulting in retransplantation, there were 5 deaths and 2 second episodes of HAT; surviving children are alive with good graft function. Of the 13 episodes managed without retransplantation, 4 patients underwent attempted early revascularisation of the graft, which was successful in 2, and the remainder initially were treated conservatively. All 13 children are alive after a median follow-up of 4.1 years (range, 0.6 to 5.8), but 5 required radiologic or surgical intervention for biliary or septic complications; biochemical liver function is normal in 8, mildly abnormal in 3, and poor in 2. Retransplantation was less likely in those who had received reduced or split grafts (7 of 17) compared with those who had received whole grafts (11 of 14), but this difference just failed to reach statistical significance (chi(2) = 3.01, 0.1 > P > .05). CONCLUSIONS: Using a selective policy of retransplantation, revascularisation, and conservative treatment, 83% of children survived HAT complicating OLT. Approximately 40% of children with HAT survived without retransplantation. J Pediatr Surg 36:888-891.

Child↗
PubMed2000

Rib abnormalities arising before and after birth.

UNLABELLED: Rib abnormalities detected in the neonatal period are usually thought to be part of a skeletal disorder. There are, however, many causes which include metabolic bone disease, infection and trauma. Rib abnormalities are also found in general disorders such as chromosomal abnormalities or hypothyroidism. CONCLUSION: A thorough examination of the neonatal chest radiograph must include the review of the skeletal parts, which can often be revealing.

Bone Diseases, Metabolic↗
PubMed1997

Developmental intrahepatic shunts of childhood: radiological features and management.

The purpose of this study was to evaluate the role of radiological techniques in the diagnosis and management of developmental intrahepatic shunts. Hepatic vascular fistulae are recognised sequelae of liver trauma and intrahepatic tumours. However, there are rare developmental malformations which may present in childhood or later life and which may carry life-threatening complications. Retrospective analysis of clinical and radiological data was carried out in 24 patients. Anomalies evaluated were: (a) direct communication between hepatic artery and hepatic veins; (b) congenital hepatoportal arteriovenous malformations; and (c) congenital portocaval anastomosis with persistent flow through the ductus venosus. Although rare, the prompt recognition of these vascular anomalies allows early surgical or radiological intervention and reversal of the haemodynamic complications.

Arteriovenous Fistula↗
PubMed1997

Retroperitoneal collections--aetiology and radiological implications.

PURPOSE: Retroperitoneal collections related to the psoas, in the absence of pancreatitis, are uncommon. This study reviews the imaging, pathogenesis and management of retroperitoneal collections with particular emphasis on distinguishing imaging features and the role of percutaneous drainage. MATERIALS AND METHODS: Twenty-three retroperitoneal collections in 22 patients were reviewed in a 2-year period. Twenty-one patients underwent computed tomography (CT), with ultrasound (US) conducted in 14 and magnetic resonance imaging (MRI) in four. The clinical history and associated aetiological factors were noted. Methods of drainage were compared, pathological/microbiological results were recorded and the clinical outcome noted. RESULTS: The mean age of presentation was 46.9 years (range 18-85 years). There was a male to female preponderance (17 to 6). Eighteen collections proved to be abscesses with five haematomas confirmed. Of the abscesses, three were primary and 15 were secondary to spinal, gastrointestinal or renal disease. Escherichia coli was the commonest isolated organism followed by Mycobacterium tuberculosis. No haematomas were drained. Twelve abscesses were drained successfully by percutaneous methods; three were managed with antibiotics alone; three were managed surgically. CONCLUSION: Secondary abscesses predominate and investigation should be directed at excluding a gastrointestinal or renal source. Tuberculous disease remains a significant problem. Percutaneous drainage allows effective management, even in the presence of a secondary abscess.

Adult↗
PubMed1997

MnDPDP-enhanced MR imaging of the liver. Correlation with surgical findings.

PURPOSE: To compare lesion detection and characterisation predicted by MnDPDP-enhanced MR imaging with surgical excision and pathological examination. MATERIAL AND METHODS: Ninety patients were intravenously infused at a rate of 2 to 3 ml/min with 5 mumol/kg mangafodipir trisodium (MnDPDP, Teslascan). The patients were examined with spin-echo and gradient-echo T1-weighted MR imaging at 1 h and 24 h after the end of infusion. The results were compared with identical pre-contrast sequences. In 20 of these patients, the pre-operative MR findings were compared with intra-operative ultrasonography and histology of the resected liver specimens. RESULTS: In those with liver metastases, there was a good correlation between MR and the hepatic disease in 11 out of 14 cases. In the group with primary liver tumours, MR findings correlated with hepatic disease in 5 out of 6 cases. CONCLUSION: Liver lesion characterisation is possible with MnDPDP, and MR contrast enhancement with this agent is considered to be an important adjunct to the radiological assessment of patients with neoplastic liver disease where accurate decisions for surgical planning are imperative.

Adolescent↗
PubMed1996

Pseudotumours of hepatic imaging.

The diagnosis of liver tumours with CT depends on differential attenuation coefficients and enhancement patterns. The sensitivity of CT in defining tumours is well established but there remain a variety of conditions that mimic these patterns, presenting a 'pseudotumour' appearance. A common illustrative example is hepatic steatosis, but less well recorded are the sphingolipidoses and intrahepatic arterioportal shunts, either post-traumatic or related to venous outflow block. Alpha-1-antitrypsin deficiency and hereditary tyrosinaemia provide examples in childhood.

Adolescent↗
PubMed1994

The use of percutaneous transluminal angioplasty in hepatic artery stenosis after transplantation.

Graft ischemia following liver transplantation is associated with a high incidence of morbidity and mortality. The present report concerns a group of seven patients in whom an anastomotic stenosis of the hepatic artery was identified. Three patients had unexplained allograft dysfunction at a median time of 28 days (range 13-64 days), and 3 had a biliary leak at a median time of 42 days after liver transplantation (range 35-270 days). In one patient the stenosis was diagnosed by routine Doppler ultrasound one week after transplant. Management was by percutaneous transluminal angioplasty at a median time of 35 days (range 13-270 days) after transplantation. After angioplasty there was a marked improvement in clinical appearance, liver function, and liver histology in 5 of the 7 patients. Those patients who had a biliary leak subsequently developed strictures that eventually required biliary tract reconstruction (hepaticojejunostomy) in two and retransplantation in one. Percutaneous transluminal angioplasty is an effective way of improving arterial blood flow in cases of anastomotic stenosis, reducing the likelihood of complete occlusion by thrombosis. If recognized early and treated promptly ischemic changes in the graft can resolve and the development of biliary strictures may be avoided.

Adult↗
PubMed1991

Selective arterial embolisation for hepatic trauma.

The technique of selective arterial embolisation for patients presenting with major hepatic trauma is described. We have used this technique successfully in four patients, three of whom had continued bleeding after emergency laparotomy. It can abolish localised intrahepatic arterial haemorrhage and arteriovenous shunting. Selective embolisation may prove to be a useful technique in reducing the mortality of major hepatic trauma.

Adolescent↗
PubMed1990

Biliary complications following orthotopic liver transplantation.

The gall-bladder conduit anastomosis (choledocho-cholecysto-choledochostomy) has been the most frequently used technique for the biliary tract anastomosis in the Cambridge/King's College Hospital joint liver transplantation programme since 1976. Cholangiograms and interventional biliary procedures performed over a 3 year period were reviewed retrospectively. Seventy-six of 148 patients managed post-operatively at King's College Hospital were studied (79 transplants). Cholangiograms were abnormal in 63 (80%) transplants with biliary strictures; inspissated bile formation, bile leak and T-tube malposition occurring in 50, 23, 14 and three transplants respectively. Anastomotic strictures occurred most frequently, predominantly at the proximal anastomosis, and the presence of inspissated bile and the T-tube in relation to these contributed towards subsequent biliary obstruction. Non-anastomotic strictures in the donor biliary tract were associated with a high position of the T-tube tip at or above the liver hilum. Saline irrigation of the bile ducts for inspissated bile or its removal via the endoscope were effective measures in the management of biliary obstruction but percutaneous balloon dilatation and endoscopic stent insertion for biliary strictures were found to have a limited role.

Adolescent↗
PubMed1990

Interventional radiology of the biliary tract. Intraductal radiation.

One palliative method of treating patients with a high duct cholangiocarcinoma is the use of 192Ir wire. This is placed through the tumor, which has been previously intubated, and delivers a high local dose of radiation. The mean survival time in 30 patients treated with intraductal radiation was 16.8 months, an improvement compared to surgical bypass or endoscopic and radiologic drainage procedures.

Adenoma, Bile Duct↗