An analysis of true- and false-positive results of vocal fold uptake in positron emission tomography-computed tomography imaging.

OBJECTIVES: Positron emission tomography-computed tomography with fluorine-18 fluorodeoxy-D-glucose has a major role in the investigation of head and neck cancers. Fluorine-18 fluorodeoxy-D-glucose is not a tumour-specific tracer and can also accumulate in benign pathology. Therefore, positron emission tomography-computed tomography scan interpretation difficulties are common in the head and neck, which can produce false-positive results. This study aimed to investigate patients detected as having abnormal vocal fold uptake on fluorine-18 fluorodeoxy-D-glucose positron emission tomography-computed tomography. METHODS: Positron emission tomography-computed tomography scans were identified over a 15-month period where reports contained evidence of unilateral vocal fold uptake or vocal fold pathology. Patients' notes and laryngoscopy results were analysed. RESULTS: Forty-six patients were identified as having abnormal vocal fold uptake on positron emission tomography-computed tomography. Twenty-three patients underwent positron emission tomography-computed tomography and flexible laryngoscopy: 61 per cent of patients had true-positive positron emission tomography-computed tomography scans and 39 per cent had false-positive scan results. CONCLUSION: Most patients referred to ENT for abnormal findings on positron emission tomography-computed tomography scans had true-positive findings. Asymmetrical fluorine-18 fluorodeoxy-D-glucose uptake should raise suspicion of vocal fold pathology, accepting a false-positive rate of approximately 40 per cent.

Modern Radiology in the Management of Head and Neck Cancer.

The accurate staging of head and neck cancer is vital to direct appropriate management strategies and to deliver the best radiation therapy and surgery. Initial challenges in head and neck cancer imaging include determination of T- and N-stage, stage migration with detection of metastatic disease and identification of primary disease in the patient presenting with nodal metastases. In follow-up, imaging has an important role in assessing patients who may require salvage surgery after radiotherapy and assessing clinical change that may represent either residual/recurrent disease or radiation effects. This overview gathers recent evidence on the optimal use of currently readily available imaging modalities (ultrasound, computed tomography, magnetic resonance imaging and positron emission tomography-computed tomography) in the context of head and neck squamous cell cancers.

Significance of tumour calcification in ovarian carcinoma.

The purpose of this study was to assess the pattern and significance of tumour calcification in ovarian carcinoma. Patients with calcifying ovarian carcinoma were identified from radiological reports. Their tumour characteristics, serum calcium levels, treatment and survival were compared with a control group of patients with non-calcifying disease. Patterns and distribution of calcification were assessed. Available serial CT scans were reviewed for changes in both soft-tissue and calcified disease according to RECIST (response evaluation criteria in solid tumours) criteria where feasible. Temporal changes in calcification were correlated with changes in soft tissue disease and CA125 levels. The calcified group numbered 122 (22 other patients had calcifying tumour but insufficient clinical data). Calcification in ovarian carcinoma had a prevalence of 8% (144/1721) in our series. There was a significant difference (p<0.001) between the two groups in the distribution of histological type, with serous tumours being more common in the calcified group (74/122 (61%)) than in the controls (509/1498 (34%)). The calcified tumour patients tended to have lower grade disease (p<0.001). No differences between the groups were found for age, treatment or serum calcium levels. Distribution of calcification was diffusely peritoneal in 34 patients, in association with a pelvic mass in 15, nodal in 11 and within the anterior abdominal wall in 2. There was no correlation between changes in calcification on serial CT scans and corresponding CA125 levels. In conclusion, calcification tends to occur most commonly in serous cystadenocarcinomata and in tumours of lower grade. Changes in calcification cannot be used as a marker of disease response.

MnDPDP enhanced magnetic resonance imaging of focal liver lesions.

Mangafodipir trisodium (MnDPDP) is a contrast agent for use in magnetic resonance imaging (MRI) of the liver. The agent is taken up by normal hepatocytes resulting in increased signal on T1-weighted imaging, and is excreted in the biliary system. Hepatocyte-containing liver neoplasms such as hepatomas or focal nodular hyperplasia (FNH), take up MnDPDP and demonstrate varying degrees of enhancement. Metastatic liver deposits and primary liver tumours of non-hepatocyte origin do not typically enhance with MnDPDP thus increasing their conspicuity compared with pre-contrast T1-weighted images. Metastases may demonstrate rim enhancement particularly on delayed imaging at 24 h, which can increase their conspicuity, thus allowing better visualization of small lesions. Functional biliary obstruction due to liver metastases can also result in wedge shaped areas of parenchymal enhancement. The MRI features of various focal liver after continuance with lesions following MnDPDP are discussed and illustrated including primary lesions such as hepatoma and secondary metastases.

Small bowel obstruction: the role of computed tomography in its diagnosis and management with reference to other imaging modalities.

Small bowel obstruction is a leading cause of acute surgical admissions for abdominal pain. There is an increasing tendency for initial conservative management rather than immediate operative intervention, as a proportion of cases will resolve spontaneously. This has resulted in a growing reliance on radiological investigations to reassure the surgeon that medical therapy can be safely instituted. The onus therefore rests with radiologists to guide their surgical colleagues by correctly interpreting the plain abdominal radiograph and suggesting appropriate further investigation if warranted. Recently, computed tomography (CT) has been proposed as the test of choice to define the level and cause of acute small bowel obstruction and to identify complications such as ischaemia and perforation which will prompt surgical intervention. This review will discuss the utility of early CT in the diagnosis of acute small bowel obstruction and outline its impact on patient management.

Mycobacterial infections: still a millennium bug--the imaging features of mycobacterial infections.

Mycobacterial infection is re-emerging as a major health care concern. Although Mycobacterium tuberculosis(MTB) is still the most important pathogen, atypical mycobacterium (AMB) infections are becoming increasingly common. We present a pictorial review of the imaging features of these infections in the chest, abdomen, brain and musculoskeletal system. Imaging similarities and differences between the normal and the immunocompromised host will be highlighted.

The utility of computed tomography in acute small bowel obstruction.

Small bowel obstruction is a significant cause of acute surgical admissions. Surgeons are tending to favour an initial trial of conservative management. Due to the unreliability of clinical signs to predict accurately those patients requiring early intervention there is an increasing tendency to utilize imaging investigations, particularly computed tomography (CT), to help define the severity, cause and complications of acute small bowel obstruction. The aim of this pictorial review is to demonstrate the contribution CT can make to the management of these patients. Burkill, G. J. C., Bell, J. R. G. & Healy, J. C. (2001). Clinical Radiology56, 350-359.

Technical report: lymph node enhancement at MRI with MnDPDP in primary hepatic carcinoma.

AIMS: To report two cases of lymph node enhancement in primary hepatic carcinoma following the administration of Mangafodipir trisodium (MnDPDP, Teslascan(R), Nycomed Amersham U.K.), an hepatocyte specific magnetic resonance imaging (MRI) contrast agent. To review our experience with this contrast agent and the literature to establish if such enhancement occurs in normal lymph nodes or has been previously described in hepatocellular carcinoma (HCC) or other lesions. MATERIALS AND METHODS: The radiological reports of all MnDPDP enhanced abdominal MRI examinations were reviewed for lymph node enlargement. The MR images from examinations with reported nodal enlargement were re-evaluated for evidence of nodal enhancement and the hospital notes and histological reports were reviewed. Nodal enhancement was considered present if lymph node signal intensity was greater than that of the spleen following MnDPDP. Literature searches were performed on Medline and PubMed for previous descriptions of lymph node enhancement following MnDPDP. RESULTS: The reports of 90 MnDPDP abdominal MRI examinations were reviewed. Of 18 cases of lymph node enlargement, two had evidence of lymph node enhancement following MnDPDP. These two cases had hepatocellular carcinoma and fibrolamellar hepatocellular carcinoma, respectively, confirmed on liver biopsy. No reports of lymph node enhancement following MnDPDP were identified in the literature. CONCLUSION: Two cases of lymph node enhancement following MnDPDP have been presented. Although histological confirmation of the lymph nodes was not obtained, the authors propose that the lymph node enhancement was due to functioning hepatocytes in lymph node metastases from the patients' histologically confirmed hepatocellular carcinomas. Burkill, G. J. C., Mannion, E. M. & Healy, J. C. (2001). Clinical Radiology56, 67-71.

Survey on the use of pulmonary scintigraphy, spiral CT and conventional pulmonary angiography for suspected pulmonary embolism in the British Isles.

AIM: To determine current clinical practice in the radiological diagnosis of acute pulmonary embolism and assess the use of spiral volumetric computed tomography. METHOD: A survey of 327 acute hospitals including cardiothoracic and orthopaedic tertiary referral centres was undertaken to assess current utilization of lung scintigraphy, spiral computed tomography and pulmonary angiography in the investigation of suspected pulmonary embolism. Responses were received from 215/327 (66%) centres. RESULTS: Lung scintigraphy was provided by 208 hospitals (144 on-site and 64 off-site). Spiral CT services were provided by 111 (52%) hospitals (on- or off-site), 142 (66%) units had access to angiographic facilities. Sixty-three centres out of 215 (29%) offered both on-site lung scintigraphy and spiral CT while only 41/215 (19%) hospitals were able to undertake all three tests on-site. On average, 501 perfusion (Q) or ventilation-perfusion (V/Q) scintigrams were performed per hospital per year with 26 spiral CT studies and just 4.6 pulmonary angiograms. CONCLUSION: These data suggest that lung scintigraphy is frequently the only imaging test in patients other than chest radiography, despite the large number of indeterminate results reported in most series.

Aneurysm of the left brachiocephalic vein: an unusual cause of mediastinal widening.

A case of left brachiocephalic venous aneurysm is presented. Thoracic venous aneurysms are rare with only 27 previous cases in the medical literature, the majority involving the superior vena cava. There are only two previous reports of isolated brachiocephalic venous aneurysm. Venous aneurysms are usually first detected as mediastinal widening on a chest radiograph and can be further defined using CT, MRI or angiography. The aetiology is uncertain. Management is usually conservative, but surgical correction has been performed.