Long-term follow-up of management of failing in situ saphenous vein bypass grafts using endovascular intervention techniques.

PURPOSE: To report the long-term follow-up of previously reported cases of salvaging failing or failed in situ bypass grafts using endovascular techniques, to include previously unreported cases, and to include the results of thrombolysis for the salvage of occluded in situ venous bypass grafts. MATERIALS AND METHODS: Between 1985 and 1995, 352 patients underwent distal bypass via the in situ saphenous vein. Seventy-three of these patients underwent endovascular interventions for (i) graft stenoses (65 lesions in 40 patients) treated by balloon angioplasty (PTA), (ii) AV residual fistulas to veins (AVF) (23 patients) occluded by coil embolotherapy, (iii) graft occlusion (21 occluded grafts in 19 patients) treated by catheter-directed high-dose thrombolytic infusion and PTA or surgical revision of uncovered stenoses, and (iv) retained valve leaflets causing stenoses (five patients) treated by valvectomy and/or PTA. Cumulative patency rates were determined by the Kaplan-Meier method. Twenty-nine of 73 patients had been previously reported by the authors. RESULTS: PTA was successful in 39 of 40 patients, cumulative patency after bypass PTA was 0.79 (SE +/- 0.07) for 12 months and 0.63 (SE +/- 0.12) for 5 years. The only complication of PTA was a graft anastomotic disruption that was successfully treated by surgery. Longer lesions and lesions requiring repeated PTA were more likely to restenose. For thrombolysis, there were 13 of 19 successful infusions and five delayed occlusions. The cumulative patency for both 12 months and 5 years was 0.43 (SE +/- 0.12). AVF embolization was successful in 21 of 23 patients. Cumulative patency for 12 months and 5 years was 0.87 (SE +/- 0.07) and 0.81 (SE +/- 0.09), respectively. Five successful valvectomy procedures were performed by stripping residual valves with endocardial forceps. CONCLUSION: In experienced hands, PTA and AVF embolization can be performed on failing in situ saphenous vein bypass grafts with good long-term patency. Thrombolysis results were less favorable but can prolong patency of grafts.

Low-dose nonenhanced helical CT of renal colic: assessment of ureteric stone detection and measurement of effective dose equivalent.

PURPOSE: To evaluate a low-dose, nonenhanced helical computed tomographic (CT) protocol in the detection of ureteric stones and measure the associated effective dose equivalent (H(E)) of radiation. MATERIALS AND METHODS: Sixty patients suspected of having renal colic and referred by emergency department physicians underwent nonenhanced helical CT with 7-mm collimation and a 2:1 pitch and then conventional intravenous urography (IVU). The two studies were prospectively and independently interpreted. The diagnostic accuracy of CT for ureteric stone detection was determined by comparing the scans with the IVU images and with a combination of clinical, surgical, and other imaging findings. The radiation risk from typical CT and IVU examinations (five images) was measured in terms of H(E) and compared with the estimated risk from two previously reported CT protocols. RESULTS: CT correctly depicted 36 of 37 ureteric stones, and one false-positive case was recorded, for a sensitivity of 97%, specificity of 96%, and accuracy of 97%. The H(E) for our CT protocol was determined to be 2.8 mSv, which is about double that for IVU and about 75% and 50% of that for two previously reported CT protocols. CONCLUSION: Our low-dose CT protocol is superior to IVU and clinically adequate for diagnosis of renal colic.

Intraarterial catheter-directed thrombolysis: urokinase versus tissue plasminogen activator.

The purpose of this study was to evaluate the differences between tissue plasminogen activator (TPA) and urokinase (UK) in the management of ischemic limbs. A total of 58 limbs (24 in the TPA group and 34 in the UK group) in 53 patients were studied prospectively. The two groups were based on the surgeon's preference for lytic agent. The dose regimen for UK was 150,000 IU/hr over 1/2 to 2 hr followed by a continuous infusion of 50,000 IU/hr. TPA was given as a 5-mg bolus followed by 1 mg/hr. Both groups received heparin at a rate of 400 IU/hr through the side arm of the arterial sheath. There was no significant difference in efficacy between UK and TPA, but TPA acted faster and had a higher incidence of bleeding complications.

Magnetic resonance imaging. Application to family practice.

OBJECTIVE: To review indications, contraindications, and risks of using magnetic resonance imaging (MRI) in order to help primary care physicians refer patients appropriately for MRI, screen for contraindications to using MRI, and educate patients about MRI. QUALITY OF EVIDENCE: Recommendations are based on classic textbooks, the policies of our MRI group, and a literature search using MEDLINE with the MeSH headings magnetic resonance imaging, brain, musculoskeletal, and spine. The search was limited to human, English-language, and review articles. Evidence in favour of using MRI for imaging the head, spine, and joints is well established. For cardiac, abdominal, and pelvic conditions, MRI has been shown useful for certain indications, usually to complement other modalities. MAIN MESSAGE: For demonstrating soft tissue conditions, MRI is better than computed tomography (CT), but CT shows bone and acute bleeding better. Therefore, patients with trauma or suspected intracranial bleeding should have CT. Tumours, congenital abnormalities, vascular structures, and the cervical or thoracic spine show better on MRI. Either modality can be used for lower back pain. Cardiac, abdominal, and pelvic abnormalities should be imaged with ultrasound or CT before MRI. Contraindications for MRI are mainly metallic implants or shrapnel, severe claustrophobia, or obesity. CONCLUSIONS: With the increasing availability of MRI scanners in Canada, better understanding of the indications, contraindications, and risks will be helpful for family physicians and their patients.

Neuroepithelial cyst of the posterior fossa: two case reports with radiologic-pathologic correlation.

The clinical, radiologic and pathological findings in two cases of neuroepithelial cyst of the posterior fossa are described. The first patient was a 43-year-old woman who presented with clumsiness of the hands, gait disturbance and slurring of speech. Magnetic resonance imaging (MRI) revealed a large cystic structure between the cerebellum and the brain stem on the left side, accompanied by compression of the medulla oblongata and displacement of the forth ventricle to the right. The second patient was an 11-month-old boy who presented with progressive bulbar dysfunction. He had previously undergone surgery for myelomeningocele and hydrocephalus associated with Arnold-Chiari type 2 malformation. MRI revealed a large cystic mass isointense with cerebrospinal fluid between the cerebellum and the midbrain, compressing the fourth ventricle and displacing the brain stem to the right. The cases were pathologically similar, the cyst containing a single layer of cuboidal epithelium and rims of neuroglial cells. Immunohistochemical staining was consistent with neuroepithelial cyst. It is important to distinguish this type of cyst from a malignant mass to ensure appropriate treatment and determine the prognosis. In addition, even though neuroepithelial cysts of the posterior fossa are benign, they are often symptomatic because of their mass effect. The second case was unusual because the cyst developed over a period of 2 months, which shows that this type of cyst can develop rapidly. To the authors' knowledge, the association with Arnold-Chiari type 2 malformation has not previously been reported.

Multiple cardiac masses diagnosed with prenatal ultrasonography in the fetus of a woman with tuberous sclerosis.

Cardiac rhabdomyomas are associated with tuberous sclerosis, but their identification in utero is uncommon. The authors report a case of multiple cardiac masses discovered in utero by prenatal ultrasonography at about 30 weeks gestational age. Follow-up included neonatal echocardiography, ultrasonography and computed tomography of the head. The differential diagnosis of echogenic intracardiac masses, as well as their management, is discussed.

Dynamic computed tomography evaluation of tracheobronchomegaly.

The authors report a case of tracheobronchomegaly in a 62-year-old man with chronic expiratory cough. Computed tomography showed dilatation of the trachea on inspiration and complete collapse of the trachea and the proximal bronchi on full expiration. The authors discuss the importance of the collapse on expiration as the cause of the patient's symptoms.