MnDPDP-enhanced MR imaging of the liver

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 μmol/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.

Manganese-enhanced MRI predicts the histological grade of hepatocellular carcinoma in potential surgical candidates

AIM

To evaluate the role of manganese-enhanced magnetic resonance (Mn-MRI) in predicting tumour differentiation prior to liver transplant or resection for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

The inclusion criteria were patients with HCC who underwent Mn-MRI prior to transplantation or resection from 2001-2008. T1-weighted MRI images were acquired at 0 and 24h after manganese dipyridoxal diphosphate (MnDPDP) intravenous contrast medium and reviewed prospectively. Manganese retention at 24h was correlated with tumour differentiation and disease-free survival.

RESULTS

Eighty-six patients underwent Mn-MRI (transplantation 60, resection 26); 114/125 lesions (91%) that were arterialised as evidenced at computed tomography (CT) and had manganese uptake on MRI were HCC. There were 11 false positives (9%) that were regenerative nodules. Ten of fourteen non-manganese-retaining HCC (71%) were poorly differentiated, compared with only 13/114 manganese-retaining HCC (11%) (p<0.0001). Sensitivity, specificity, positive and negative predictive values of non-retention of MnDPDP in predicting poorly differentiated tumours were 0.43, 0.96, 0.71 and 0.88. Median disease-free survival of patients with non-manganese-retaining HCC was less than for patients with manganese-retaining HCC (14±5 months versus 39±3 months, log rank p=0.025).

CONCLUSION

Non-manganese-retaining HCCs are likely to be poorly differentiated and have a poor prognosis. Manganese-enhanced MRI appears to have a role in preoperative assessment of HCC and warrants further evaluation.

Role of imaging in the management of pancreatic mass

Pancreatic cancer is the second commonest malignant gastrointestinal neoplasm. Modern imaging techniques have greatly increased sensitivity in diagnosing and staging pancreatic cancers. Multidetector CT in particular, plays a critical role in local staging and determining the resectability of pancreatic tumours. MR and endoscopic ultrasound are valuable in those groups of patients in whom CT findings alone are inconclusive in tumour characterisation and local staging, particularly vascular involvement. In this article we review the current established concepts and the role of imaging in the multidisciplinary management of pancreatic tumours together with a comprehensive review of the literature.

Vanishing liver tumours

Spontaneous resolution of liver tumours is a rare, but recognized entity that has been reported to occur within the spectrum of benign and malignant liver tumours occurring in both adult and paediatric population. The aetiology of this unusual phenomenon is not clearly understood. In this article we present case examples of various benign and malignant liver tumours that have regressed spontaneously without treatment together with a review of the literature, and a summary of the current understanding of the pathogenesis of these tumours.

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.

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.

Abdominal complications from crack cocaine

Not only is cocaine a powerfully addictive and dangerous drug of abuse, the use of the purified cocaine derivative crack has also reached epidemic proportions. Apart from causing fatal cardiorespiratory complications, crack cocaine is capable of producing surgical emergencies, which may or may not be associated with the pharmacology of cocaine itself. This is a report of crack-induced pneumoperitoneum, the mechanism of which seemed to be related to the prolonged Valsalva manoeuvre during crack smoking. Other differential diagnoses of crack related pneumoperitoneum are also discussed.

Hepatic artery pseudoaneurysms following liver transplantation: incidence, presenting features and management

AIM

Hepatic artery pseudoaneurysm (PA) is an uncommon complication of liver transplantation. We report a series of 13 patients, the largest published review including outcome. The presenting features, risk factors and role of radiology in the diagnosis and management of this frequently fatal complication are discussed.

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.

Segmental portal hypertension due to splenic vein obstruction: imaging findings and diagnostic pitfalls in four cases

Segmental portal hypertension due to isolated splenic vein obstruction is a rare but important entity as it is the only curable cause of portal hypertension by splenectomy. Four cases are presented illustrating the radiological features of splenic vein obstruction, and the diagnostic pitfalls that arose in patients with complicated clinical presentations.

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.

Accuracy of radiology in detection of hepatocellular carcinoma before liver transplantation

BACKGROUND/AIMS

Recurrence of hepatocellular carcinoma (HCC) after orthotopic liver transplantation (OLT) depends on tumor size and number; the accuracy of radiology in detecting HCC is uncertain. This study compared tumor size at radiological and pathological examination in 30 patients with HCC who underwent OLT.

METHODS

Pre-OLT radiology included ultrasonography (US), computerized tomography (CT), and hepatic angiography (HA). Sensitivity of radiology was calculated by comparison with pathology.

RESULTS

Radiology missed HCC in two patients but showed five with small (< 4 cm) and eight with large (> 4 cm) lesions. Multicentricity was shown in 15 cases at radiological examination and 24 at pathological examination, including one incidental and 4 of 5 radiologically small HCC. Mean tumor bulk was 3.4, 74, 338, and 1375 cm3, respectively, in patients with incidental, small, large, and multicentric HCC at radiology. Sensitivities of US, CT, and HA in detection of HCC (and multicentricity) were 80% (16.6%), 86.6% (58.3%), and 90% (58.3%). No recurrence was found in patients with incidental or small HCC; even when multicentric.

CONCLUSIONS

US, CT, and HA identified patients with small or large tumor bulk, but sensitivity in detecting satellites was poor; their finding in patients with radiologically small or incidental tumors does not affect outcome. The failure of US, CT, and HA to detect satellites must be considered in patients undergoing partial hepatectomy for HCC.