Imaging in bariatric surgery: service set-up, post-operative anatomy and complications.

Obesity is an increasingly prevalent and costly problem faced by the healthcare system. The role of bariatric surgery in managing obesity has also increased with evidence showing a reduction in long-term morbidity and mortality. There are unique challenges faced by the radiology department in providing an imaging service for this population of patients, from technical and staffing requirements through to the interpretation of challenging post-surgical images. We describe these challenges and provide an overview of the most frequently performed procedures, normal post-operative imaging findings and the appearance of common complications.

Variation of mesorectal volume with abdominal fat volume in patients with rectal carcinoma: assessment with MRI.

The purpose of this study was to assess the variability in the volume of the mesorectum in patients with rectal carcinoma. A retrospective review was made of pelvic MRI studies in 30 patients (mean age 64 years, range 34-88 years, 18M:12F) with histologically proven rectal carcinomas that were confined to the mesorectum. The outer low signal margin of the mesorectum was traced, over at least 10 consecutive 10 mm contiguous slices, until its disappearance. The visceral fascial compartment, body cross-sectional area and body mass index were measured, on a solitary slice, at the level of the L5/S1 disc. Linear regression was calculated for independent determinants of the mesorectal volume. Mean mesorectal volume in males was 227.5 cm3 (95%CI 191.6-263.4), and in females was 157.5 cm3 (95%CI 129.3-185.7). The difference in mesorectal volume between men and women was statistically significant (p<0.001). Mean visceral compartment area in males was 18.4 cm2 (95%CI 16.3-20.5) and in females was 14.6 cm2 (95%CI 12.8-16.4). Visceral compartment area correlated with mesorectal area and volume in females (p<0.05), and extremely well in males (p<0.005). Body cross-sectional area, body mass index and age did not correlate with mesorectal size. The correlation of visceral compartment area with mesorectal volume and mean area suggests that the mesorectum is determined in a similar way to other body fat compartments, with a similar anatomical variation. This significant variation in size and volume may have an important prognostic implication in patients with rectal carcinoma. This volume can be measured and reported on pre-operative MRI scanning and may be communicated to surgeons and radiotherapists.

Radiology of gestational trophoblastic neoplasia.

Gestational trophoblastic neoplasia (GTN) encompasses a broad spectrum of placental lesions from the pre-malignant hydatidiform mole (complete and partial) through to the malignant invasive mole, choriocarcinoma and rare placental site trophoblastic tumour (PSTT). Ultrasound remains the radiological investigation of choice for initial diagnosis, and it can also predict invasive and recurrent disease. Magnetic resonance imaging is of invaluable use in assessing extra-uterine tumour spread, tumour vascularity, and overall staging. Positron emission tomography and computed tomography undoubtedly have a role in recurrent and metastatic disease, while angiography has a place in disease and complication management. This review will describe the relevant pathophysiology and natural history of GTN, and the use of imaging techniques in the diagnosis and management of these conditions.

Warfarin-associated thoracic aortic dissection in an elderly woman.

BACKGROUND: The risk/benefit ratio of warfarin therapy changes in the over 75s, when haemorrhagic side-effects become more common. These may not always be reported in the literature. CASE REPORT: A woman of 80 years, on long-term warfarin therapy presented with an acute dissecting thoracic aortic aneurysm; on investigation the only precipitating factor found was an international normalised ratio of 4.8. This patient, who also had an abdominal aortic aneurysm, survived, on discontinuation of her anticoagulant therapy. CONCLUSIONS: We describe a previously unreported complication of warfarin therapy in a patient over 75 years of age, to add to the cautions in prescribing this drug in patients of this age group.

Evaluation of the role of pre-operative magnetic resonance imaging in the management of rectal cancer.

OBJECTIVES: This study assesses the ability of body coil magnetic resonance imaging (MRI) to pre-operatively stage mural penetration, nodal status and circumferential resection margin (CRM) involvement of rectal cancer. PATIENTS AND METHODS: Between 1995 and 1997, MRI using a body coil was performed in consecutive patients with primary rectal carcinomas. Group A: 67 patients underwent surgery without long course neo-adjuvant therapy. Predicted tumour stage was compared to the histology of the specimen. Group B: 21 patients with MRI evidence of advanced disease, underwent long course neo-adjuvant therapy followed by repeat MRI prior to surgery. The second scan assessed response to treatment and likelihood of CRM involvement at subsequent surgery. RESULTS: Group A: Accuracy of pre-operative staging was: 'T' stage - 54%, 'N' stage - 77%, involvement of CRM by tumour - 97%. Group B: After long course neo-adjuvant therapy the second MRI scan was 95% accurate in predicting CRM involvement by tumour. CONCLUSION: In this study pre-operative rectal cancer staging with MRI and a body coil lacks accuracy in predicting mural penetration and nodal involvement. Body coil MRI can accurately predict the potential for CRM involvement. This technique may help determine which patients require long course neo-adjuvant therapy.

The radiological investigation of suspected lower limb deep vein thrombosis.

A postal survey was performed to determine the current practices and attitudes of radiologists towards the imaging of suspected lower limb deep vein thrombosis (DVT). One hundred and twenty-seven departments responded to a questionnaire sent in March 1996. The results show that 87% of hospitals possess colour Doppler ultrasound (CDUS) machines and that 46% of departments perform ultrasound as the first line investigation in over 90% of cases. Thirty per cent of departments considered calf vein visualization to be generally adequate and 34% thought that clinicians in their hospitals invariably anticoagulated patients with isolated calf thrombus. In hospitals where venography was routinely used as the first line investigation, the most common reasons were: the perceived inferiority of ultrasound (US) in demonstrating below-knee clot, its time-consuming nature and the limited access to suitable ultrasound machines. The widespread use of ultrasound is encouraging, however, there are clearly diverse views. A significant minority of departments depend principally upon venography in the diagnosis of DVT.

Imaging of small cell carcinoma of the male urogenital tract.

Five cases of small cell carcinoma (three of the prostate and two of the bladder) are described to illustrate the unusual behaviour of these tumours. Cerebral, hepatic and bulky lymph node spread with large volume local disease occurred. The role the radiologist may play in these diseases is discussed.

Radiographic manifestations of AIDS related lymphoma in the thorax.

Intrathoracic disease in AIDS-related lymphoma (ARL) produces a range of radiographic appearances. This study aimed to determine the frequency, distribution and characteristics of these appearances. The case notes and findings on imaging of 116 consecutive cases of ARL were reviewed retrospectively. In 52 cases there were abnormalities present on chest imaging (chest radiography or chest CT scanning). In 20 patients abnormalities were judged to be due to lymphomatous involvement and in 15 cases the thorax was the major site of disease. Correlation with biopsy results from thoracic disease (9), other disease (5), or evidence of response to treatment (6) was made. The most frequent imaging findings were pleural or intrapulmonary masses (7), frequently peripheral and sometimes with cavitation. In one case this simulated mycetoma formation. Pleural effusions and mediastinal lymph nodes were also frequently present, either alone or in combination. AIDS-related lymphoma uncommonly involves the chest as a major site of disease. A pleural or intrapulmonary mass with cavitation may represent the only site of disease and in these cases CT guided biopsy is likely to provide the histological diagnosis.