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Superior vena cava (SVC) obstruction commonly occurs in the setting of malignancy. Cases of benign SVC obstruction are being seen more frequently with the use of long-term central venous lines. This is the case particularly in Cystic Fibrosis (CF). We describe in this report the successful use of intravascular stenting to treat this distressing condition in the setting of thrombotic occlusion of the SVC in a patient with CF.

Objective: Many studies have reported the use of attenuation-corrected positron emission tomography with 18F-fluorodeoxyglucose (FDG PET) with full-ring tomographs to differentiate between benign and malignant pulmonary nodules. We sought to evaluate FDG PET using a partial-ring tomograph without attenuation correction., Methods: A retrospective review of PET images from 77 patients (range 38-84 years of age) with proven benign or malignant pulmonary nodules was undertaken. All images were obtained using a Siemens/CTI ECAT ART tomograph, without attenuation correction, after 185 MBq 18F-FDG was injected. Images were visually graded on a 5-point scale from "definitely malignant" to "definitely benign," and lesion-to-background (LB) ratios were calculated using region of interest analysis. Visual and semiquantitative analyses were compared using receiver operating characteristic analysis., Results: Twenty lesions were benign and 57 were malignant. The mean LB ratio for benign lesions was 1.5 (range 1.0-5.7) and for malignant lesions 5.7 (range 1.2-14.1) (p < 0.001). The area under the ROC curve for LB ratio analysis was 0.95, and for visual analysis 0.91 (p = 0.39). The optimal cut-off ratio with LB ratio analysis was 1.8, giving a sensitivity of 95% and a specificity of 85%. For lesions thought to be "definitely malignant" on visual analysis, the sensitivity was 93% and the specificity 85%. Three proven infective lesions were rated as malignant by both techniques (LB ratio 2.6-5.7)., Conclusions: FDG PET without attenuation correction is accurate for differentiating between benign and malignant lung nodules. Results using simple LB ratios without attenuation correction compare favourably with the published sensitivity and specificity for standard uptake ratios. Visual analysis is equally accurate.

Objective: The purpose of this study was to evaluate the ease, completeness, and clinical utility of double-contrast barium enema (DCBE) performed immediately after incomplete colonoscopy., Subjects and Methods: During a 30-month period, a prospective study was performed in 103 patients (79 women, 24 men) to determine the ease and completeness of DCBE immediately after failed colonoscopy and any additional useful information provided by the enema. The ease with which DCBE was performed was graded from 1 (easy) to 10 (difficult)., Results: DCBE revealed the entire colon in 97 patients (94%). Incomplete DCBE was a result of obstruction and incontinence in three patients each. The mean score for ease of performing DCBE was 5.0. In 14 patients (14%), significant additional diagnostic information was provided by the immediate DCBE. In eight patients, abnormalities were identified on DCBE that had not been seen at colonoscopy (five malignant neoplasms, one diverticular mass, two extrinsic masses, and multiple strictures). In four patients, a suspected colonoscopic abnormality was excluded with DCBE findings; and in two patients, a colonoscopic abnormality was further characterized with DCBE., Conclusion: Immediate DCBE after incomplete colonoscopy allows complete colonic evaluation in most cases, often adds vital diagnostic information, and eliminates repeated bowel preparation and unnecessary delay in diagnosis.

Purpose: To evaluate the safety and effectiveness of a systematic protocol for sedation and analgesia in interventional radiology., Materials and Methods: Ninety-one adult patients underwent 113 abdominal interventional procedures. Fentanyl citrate and midazolam hydrochloride were administered in one to five steps (A, B, C, D, E) until the patient was drowsy and tranquil at the effective loading dose (ELD). Doses per step were as follows: A, fentanyl 1 microg per kilogram of body weight; B, midazolam 0.010-0.035 mg/kg; C, repeat dose in A; D, repeat half the dose in B; and E, midazolam 1-2-mg boluses (maximum, 0.15 mg/kg)., Results: The ELD was reached in no procedure after step A, in 70 after B, in 23 after C, and in 18 after D. Step E was needed in two procedures. The mean maximum pain score (scale of 0 to 10) was 3.4; pain scores in 85 (75%) procedures were 4 or less (discomforting). Severe pain occurred in seven (6%) procedures. Hypoxia (oxygen saturation < 90%) occurred in 11 (22%) procedures performed in patients breathing room air and four (6%) performed in those breathing supplemental oxygen (P: =.04). All patients responded to supplemental oxygen., Conclusion: This stepwise "ABCDE protocol" allows safe and effective sedation of patients. It is easy to use and may be useful in training radiology residents, staff, and nurses in the techniques of sedation and analgesia. Supplemental oxygen should be used routinely.

Aims: To compare the diagnostic performance of hepatic arterial (HA) Doppler ultrasound post-liver transplantation for hepatic artery thrombosis and stenosis in our unit with the literature. To evaluate the role of the technique in clinical practice., Materials and Methods: In a two-phase 'audit cycle' study, adult OLT patients had Doppler studies comprising detection of HA flow and measurements of peak systolic velocity, resistive index and systolic acceleration time. In phase I, patients had Doppler examinations 'routinely' and for any hepatic biochemical abnormality. In phase II, Doppler ultrasound was performed early post-OLT and later only if a senior transplant clinician suspected graft ischaemia. In addition to HA measurements the waveform was visually assessed. Clinical outcome was the 'gold standard'., Results: Phase 1: 38 patients, 40 OLT operations, 125 Doppler studies; 14 arteriograms. Phase 2: 35 patients, 42 OLT operations, two HA angioplasties, one HA revision, one non-occlusive thrombus, 140 studies; 17 arteriograms. Results; Phase 1 [Phase 2]: sensitivity 80% [100%]; specificity 71% [81%]; PPV 28% [56%]; NPV 96% [100%]; incidence of HA abnormality 12.5% [19. 5%]; likelihood ratio of negative result 0.28 [0]; of positive result 2.8 [5.3]., Conclusion: Previously reported results are reproducible. Normal HA waveform should also be a criterion of normality. The technique is very sensitive but relatively non-specific. Predictive values improve with discriminate use. MacEneaney, P. M. (2000). Clinical Radiology55, 517-524., (Copyright 2000 The Royal College of Radiologists.)

Aims: The pneumocolon technique in small bowel meal examination is used to obtain double-contrast views of the distal ileum. The purpose of this study was to determine the proportion of cases in which an overhead pneumocolon radiograph demonstrated clinically relevant findings in the colon., Methods: The overhead pneumocolon radiographs in 151 patients who underwent small bowel meals were evaluated retrospectively. A chart review was performed on those patients with positive colonic findings to determine if the suspected abnormalities affected patient management., Results: Colonic abnormalities were identified in 34 of the 151 patients. One patient had a previously undiagnosed ascending colonic cancer; 17 had evidence of acute or chronic colitis; 13 had diverticulosis; one had a caecal polyp; one had an ileosigmoid fistula; one had a filling defect in the ascending colon. In 25 cases the colonic abnormality was visible only on the pneumocolon radiograph and not on the preceding single-contrast images. Management was altered by the colonic findings in seven cases. False-positive findings occurred in two cases., Conclusions: A routine overhead radiograph following use of the pneumocolon technique is a useful adjunct to small bowel meal examination as it can yield unsuspected and clinically significant colonic findings.Chou, S. (2000). Clinical Radiology55, 459-464., (Copyright 2000 The Royal College of Radiologists.)

Because of the poor prognosis for patients with esophageal cancer and the risks associated with surgical intervention, accurate staging is essential for optimal treatment planning. Positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) is a useful adjunct to more conventional imaging modalities in this setting. FDG PET is not an appropriate first-line diagnostic procedure in the detection of esophageal cancer and is not helpful in detecting local invasion by the primary tumor, and further studies are required to determine its efficacy in the detection of local nodal metastases. However, FDG PET is superior to anatomic imaging modalities in the ability to detect distant metastases. Metastases to the liver, lungs, and skeleton can readily be identified at FDG PET. In addition, FDG PET has proved valuable in determining the resectability of disease and allows scanning of a larger volume than is possible with computed tomography. Recurrent disease is readily diagnosed and differentiated from scar tissue with FDG PET. In addition, FDG PET may play a valuable role in the follow-up of patients who undergo chemotherapy and radiation therapy, allowing early changes in treatment for unresponsive tumors. The management of most patients with esophageal cancer can be improved with use of FDG PET.

Positron emission tomography (PET) with 18F-fluoro-2-deoxyglucose (FDG) has recently emerged as a practical and useful imaging modality in patients with lung cancer. Malignant tumours demonstrate increased uptake of FDG, a positron-emitting radiopharmaceutical. This increased FDG uptake in tumours can be seen using PET. FDG PET has much higher accuracy than other imaging modalities for the differentiation of benign and malignant lung nodules. The sensitivity of PET is 96% and the specificity 77% for diagnosing malignant nodules. PET is also more accurate than computed tomography (CT) for staging mediastinal nodal involvement (sensitivity 89%, specificity 94%). While CT relies on an arbitrary anatomical cutoff of 1 cm to diagnose malignant nodes, which may simply be enlarged due to inflammation, PET can accurately diagnose metastases in nodes smaller than 1 cm. Several studies have shown significantly better staging of distant metastases with FDG PET than with traditional techniques such as bone scanning. Differentiation of recurrent disease from scar tissue in the postoperative patient is often difficult with CT or magnetic resonance imaging. The low uptake of FDG in scar tissue allows reliable differentiation between scar tissue and a recurring tumour with PET. Early studies suggest a promising role for PET in the evaluation of response to chemotherapy. This may allow treatment to be changed after only one course of chemotherapy, instead of waiting for anatomical disease progression to become obvious clinically or with CT. Finally, significant improvements in cost effectiveness have been demonstrated when FDG PET is added to the preoperative work-up of patients with lung cancer.

Purpose: To describe the MR appearances of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy., Methods: MR examinations were performed on 15 family members (both symptomatic and asymptomatic). The phenotype was defined by the presence of abnormalities on MR scanning in genetically susceptible individuals., Results: There were 10 abnormal and 5 normal MR scans. Three subjects with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy had moderate or severe neurologic deficits, 4 had transient focal neurologic symptoms, 2 had migraine, and 1 was asymptomatic (all these had abnormal MR scans). Only 1 subject with migraine had a normal MR. Four other asymptomatic family members had normal scans. Two main abnormalities emerged. First, small, linear, and punctate lesions were identified in the periventricular white matter, brain stem, basal ganglia, and thalamus. Second, large confluent patches of abnormal tissue were present in subcortical regions that often were symmetric and had a tendency to occur in the temporal lobes., Conclusions: The diffuse myelin loss and small infarcts that cause cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy are well demonstrated with MR. Presymptomatic abnormalities can be seen on MR.