The radiological management of the thrombosed arteriovenous dialysis fistula.

Patent vascular access is a prerequisite for adequate haemodialysis, and is a major determinant of quality of life and long-term survival of patients with end-stage renal disease. Autogenous haemodialysis fistulas (AVFs) have demonstrated superior clinical outcome when compared to synthetic grafts, but both types of access remain susceptible to venous stenoses, and consequent thrombotic occlusion. Recent publications have reported primary patency rates of up to 100% following percutaneous de-clotting of AVFs incorporating techniques such as pharmacological thrombolysis, mechanical thrombectomy, and thrombo-aspiration. Endovascular management also provides information regarding the underlying cause of access thrombosis, with option to treat. Consequently, there has been a paradigm shift in the management of fistula thrombosis, with interventional radiology assuming a lead role in initial salvage procedures. This article will attempt to provide the reader with an insight into the multiple radiological techniques that can be employed to salvage a thrombosed AVF based on current published literature.

Percutaneous treatment of pseudoaneurysms using fibrin adhesive.

This study was performed to assess the safety and efficacy of treatment of iatrogenic pseudoaneurysms with fibrin adhesive. 28 patients with iatrogenic pseudoaneurysms were treated. The first 20 patients had either at least one previously unsuccessful treatment of ultrasound guided compression repair (UGCR), a contraindication to UGCR or could not tolerate the procedure. Diagnosis was confirmed on ultrasound and angiography and a balloon inflated across the neck of the pseudoaneurysm. Fibrin adhesive was injected under ultrasound control directly into the pseudoaneurysm sac. The balloon was deflated after 15 min and check ultrasound and angiography performed, with a further ultrasound at 24 h. The subsequent eight patients underwent embolisation as the first line treatment without use of a protective balloon. 16 of the first 20 patients (80%) and all of the subsequent 8 patients had successful embolisation of the pseudoaneurysm after a single treatment. Two pseudoaneurysms failed to thrombose despite two treatments in one case and three treatments in the other, and both required surgery. The only significant complication was the development of local cellulitis in one patient. In conclusion, embolisation of iatrogenic aneurysms with fibrin adhesive is a safe and effective treatment. It should be considered as an alternative to surgery and UGCR.

Rotational digital subtraction angiography of the renal arteries: technique and evaluation in the study of native and transplant renal arteries.

Rotational digital subtraction angiography (RDSA) allows multidirectional angiographic acquisitions with a single injection of contrast medium. The role of RDSA was evaluated in 60 patients referred over a 7-month period for diagnostic renal angiography and 12 patients referred for renal transplant studies. All angiograms were assessed for their diagnostic value, the presence of anomalies and the quantity of contrast medium used. The effective dose for native renal RDSA was determined. 41 (68.3%) native renal RDSA images and 8 (66.7%) transplant renal RDSA images were of diagnostic quality. Multiple renal arteries were identified in 9/41 (22%) native renal RDSA diagnostic images. The mean volume of contrast medium in the RDSA runs was 51.2 ml and 50 ml for native and transplant renal studies, respectively. The mean effective dose for 120 degrees native renal RDSA was 2.36 mSv, equivalent to 1 year's mean background radiation. Those RDSA images that were non-diagnostic allowed accurate prediction of the optimal angle for further static angiographic series, which is of great value in transplant renal vessels.

Assessment of osteopenia from spine radiographs using two different methods: the Chingford Study.

Two methods for diagnosing radiological osteopenia in thoracic (TS) and lumbar (LS) spine radiographs were assessed: a subjective conventional method (A) and a semiquantitative method (B), by comparing them with bone mineral density (BMD) measured by dual energy X-ray absorptiometry (DEXA), in a population of "normal" women aged 45-70 years (n = 818). For both methods there was good intraobserver and interobserver reproducibility. BMDs were significantly lower with increasing radiological osteopenia grades (p < 0.001), and remained lower after adjustment for age and body mass index (p < 0.01). The proportion of subjects with DEXA-defined osteoporosis rose with increasing radiological osteopenia grades for both methods. The worst osteopenia categories identified 29.7-55.3% of women with DEXA-defined osteoporosis, compared with 6.1-11.7% in the "normal" categories. Both methods, however, showed a large degree of overlap of BMDs between the various radiological osteopenia grades. The sensitivity and specificity of method A in diagnosing osteoporosis were 45.3% and 78.4%, respectively, for the TS and 19.0% and 94.3%, respectively, for the LS. For method B the sensitivities and specificities were 8.8% and 96.1%, respectively (TS), and 10.2% and 95.6%, respectively (LS). Although both methods have poor sensitivities, "definite" or "high" grade osteopenia should be an indication for bone densitometry. The high specificities suggest that a "normal" (no osteopenia) X-ray is unlikely to have a significantly low BMD.

Evaluation of head examinations produced with a mobile CT unit.

Recent years have seen the development of mobile CT units, designed for use in operating theatres, intensive care units and accident and emergency departments. One such unit is the Tomoscan M (Philips, Utrecht, The Netherlands). It operates with a maximum tube voltage of 130 kV, and a maximum tube current of only 50 mA. This study tested whether acceptable quality CT images of the brain could be produced on the mobile unit with these parameters. 44 consecutive normal head examinations performed on the mobile scanner were compared with 35 examinations from two conventional CT units. Two independent readers scored the examinations for noise and artefact. CT dose index (CTDI) values for the three CT units were obtained in free air as an estimate of patient dose. Differences in artefact score between CT units were generally small, but noise scores were worse when using the Tomoscan M with a 2 s slice time. The lowest CTDI values were obtained with the Somatom DRH (Siemens, Erlangen, Germany) unit and the highest with the SR 7000 (Philips, Utrecht, The Netherlands), with values from Tomoscan M, in all except one case, falling between these values for the protocols used in the study. The measured scattered radiation doses from the Tomoscan M are presented.

Embolisation of cancer: what is the evidence?

Embolisation has become an accepted modality of cancer treatment in patients with a variety of clinical scenarios. It is commonly used in clinical practice in the treatment of hepatocellular carcinoma, hepatic metastases from colorectal cancer and neuroendocrine tumours, and renal cell carcinoma. This review summarizes the current evidence for the efficacy of embolotherapy in these clinical settings, together with the associated complications.

A comparison of air, CO2 and an air/CO2 mixture as insufflation agents for double contrast barium enema.

Using CO2 for DCBE is recommended as it may decrease pain afterwards but recent studies suggest it produces inferior distension. This prospective double blind study was designed to evaluate the use of an air/CO2 mixture. We randomised 105 patients to receive air, CO2 or a 50/50 mixture as the insufflation agent in DCBE. Gases were administered from prefilled bags. Those requiring additional insufflations before over couch films were recorded. Post procedure symptoms were evaluated by questionnaire. Distension and mucosal coating were assessed independently. There was no difference in mucosal coating. Those given CO2 had significantly less immediate and delayed pain compared to air and less delayed pain compared to the 50/50 mixture. Distension with air was graded better than with the other two agents but the difference did not reach statistical significance. However 50 % of patients receiving CO2 and 40 % of those receiving the mixture required additional insufflation before over couch films as distension was considered suboptimal, compared to 17 % of those given air, which was statistically significant. Our results indicate that using CO2 causes less pain than using air or the mixture although top up insufflations are often required to maintain adequate quality distension.