Pediatric abdominal trauma: evaluation by computed tomography.

When indications for immediate laparotomy are not present, CT of the abdomen and pelvis can be used to evaluate pediatric blunt abdominal trauma. During 2-year period, the medical records and abdominal/pelvic CT scans of 100 consecutive pediatric patients who were evaluated for blunt abdominal trauma were retrospectively reviewed. The scans appeared normal for 73 children. Of these children, 30 had severe head injuries and a depressed sensorium. A total of 27 abdominal/pelvic CT scans were interpreted as abnormal. Findings included nine splenic fractures, six renal contusions, nine hepatic lacerations, one duodenal hematoma, one traumatic pancreatitis, four bony injuries, six miscellaneous abnormalities, and one intraperitoneal bleed. Only two of these 27 patients required abdominal surgery. The remaining 25 patients were treated conservatively based upon a stable clinical state and CT delineation of the extent of injury. No mortality resulted. CT is the radiographic examination of choice for hemodynamically stable pediatric patients with blunt abdominal trauma. CT provided a reliable adjunct examination technique when a physical examination could not be performed and a complete history could not be obtained. The extent of abdominal/pelvic injuries is well delineated and can often be followed by diagnostic imaging, usually allowing for conservative therapy.

Advances in ultrasound imaging of venous thrombosis.

In the contemporary clinical setting, a diagnosis of deep vein thrombosis can be established using ultrasound. While different ultrasound modalities, including direct B-mode venous imaging, Doppler, and vein compression, have been employed to diagnose clot, it is the compression technique that has been established as the dominant method. In venographically controlled series, compression ultrasound has demonstrated a 93% sensitivity and 99% specificity for clot detection. These remarkable results have been achieved without the evaluation of calf veins. Recent improvements in instrumentation have permitted the direct visualization of calf veins, and it would seem likely that this will result in even better sensitivity for clot detection.

Percutaneous large bore venotomy and tract creation: comparison of sequential dilator and angioplasty balloon methods in a porcine model. Preliminary report.

We used a pig model to evaluate the pathologic changes that occur during large caliber percutaneous venotomy and tract creation such as is necessary to deliver the Greenfield vena caval filter. Four sequential dilator and four angioplasty balloon tract creations were performed on eight external jugular veins in four adult pigs. Gross and microscopic evaluations of the veins and surrounding tissue followed the procedures. Morphometric measurements based on extent and severity of pathologic changes in the specimens were graded from 0 (normal) to 3 (severe and/or extensive). We found that while either technique entailed damage to the veins, the sequential dilator method produced substantially more smooth muscle stretching and tearing and disruption of the internal elastica. There also was greater perivascular and intramural hemorrhage. These changes extended as far distally as the catheters and sheaths were advanced. While the number of experimental samples is too small to allow valid statistical analysis, our results suggest that the angioplasty balloon technique may be superior for tract and venotomy creation. Furthermore, large sheaths should be advanced only enough to maintain venous access to limit the extent of potential venous damage.

Arteriosclerosis obliterans in a rabbit model.

RATIONALE AND OBJECTIVES: The authors induced atherosclerotic occlusions in a rabbit model, using and comparing different experimental methods. METHODS: Lesions were induced in 40 femoral arteries in 20 rabbits. Four combinations of lesion induction methods were used: 1) drying of the endothelium with carbon dioxide gas; 2) gas-drying of the artery plus mechanical injury; 3) gas-drying plus induced thrombosis of the treated segment using thrombin; and 4) gas-drying, mechanical injury, and induced thrombosis. All rabbits were fed a high-fat, high-cholesterol diet for 1 to 2 months after lesion induction. RESULTS: Seventeen rabbits were available for follow-up. Sixty-eight percent (13 of 19) of femoral arteries treated with thrombin-induced thrombosis demonstrated atherosclerotic occlusions, compared with 27% of those that did not receive this treatment (4 of 15; P < .01). CONCLUSIONS: Thrombin-induced thrombotic occlusion of a segment of artery which has been de-endothelialized, followed by a high-fat, high cholesterol diet, results in a higher yield of experimental occlusive atherosclerosis in rabbits than is achievable by other methods.

Medical student attitudes toward radiology. A multi-institutional survey.

A questionnaire was administered to 238 students at four institutions before and after a radiology clerkship to evaluate student attitudes regarding radiology as a career, radiologist expertise, and clerkship expectations. There was no statistically significant difference among the clerkships, although they varied in types of experience, geographic location, and size. After the clerkship, the students agreed more strongly that the radiologist should be involved in patient workup, screening of requests, interpretation of emergency room films, and consultations. A significant change in attitude could be identified after the four-week experience, indicating a desire for the radiologist to have a more active role as imaging consultant.

Percutaneous inferior vena cava cannulation for long-term parenteral nutrition.

Thrombosis of the superior vena cava and its contributory veins from previous parenteral nutrition catheters precluded this approach for a new Hickman catheter in a patient with short-gut syndrome. Percutaneous puncture of the inferior vena cava with subcutaneous tunneling of the catheter to the anterior chest wall provided good access to the central venous circulation for long-term parenteral nutrition.

Vertebral artery pseudoaneurysm. A rare complication of subclavian artery catheterization.

The present case report details a previously unreported complication of subclavian vein catheterization, vertebral artery pseudoaneurysm. Attention to this problem was brought about in the patient by the development of stridor and dysphagia noted 5 days following placement of the subclavian catheter. A computed tomographic scan of the neck revealed a superior mediastinal, contrast-enhancing mass in the region of the right subclavian artery with a "bull's-eye" sign suggestive of a pseudoaneurysm. Arteriography subsequently proved the pseudoaneurysm to be of vertebral origin. The pseudoaneurysm was ligated via a neck incision together with a median sternotomy to obtain vascular control. The evaluation and treatment options of this problem are discussed.

Venous ultrasonography.

Compression ultrasonography supplemented by pulsed and color Doppler imaging is the diagnostic modality of choice for evaluating lower extremity deep vein thrombosis in symptomatic and asymptomatic high-risk patients. Furthermore, this technique frequently can characterize the clot as occlusive or nonocclusive or acute or chronic and can define the extent of disease. In patients without thrombosis, this modality can suggest an alternative diagnosis in 12% of patients.

Compression ultrasonography for the detection of deep venous thrombosis in patients who have a fracture of the hip. A prospective study.

The effectiveness of compression ultrasonography in the detection of femoral and popliteal venous thrombosis was determined in a prospective trial over a period of seven months. Forty-two patients who had an isolated intertrochanteric or femoral neck fracture participated, and forty of these patients completed the study. The average age of the patients was 81.6 years. Venography was the standard with which all ultrasonic studies were compared. A total of 112 ultrasonic studies were performed. The incidence of major venous thrombosis, as detected by venography, was 12.5 per cent. All patients were clinically asymptomatic. The compression ultrasonic technique had an accuracy of 97 per cent, a sensitivity of 100 per cent, and a specificity of 97 per cent. Compression ultrasonography appears to be a very effective technique for diagnosing venous thrombosis in patients who have a fracture of the hip. It is safe, well accepted by both patients and staff, and simply and quickly performed, and it carries no inherent risks. It also can be readily repeated, making it ideal for monitoring high-risk patients.

Percutaneous alternatives in nutritional support: a radiologic perspective.

As alternatives to per os feeding and nutritional support increase in number and complexity, the interventional radiologist has come to play a more significant role in the creation and maintenance of nutritional access. In very difficult access cases, the concerted effort of the nutritional surgeon and the radiologist is often required. We describe several such situations which have been successfully managed at our institution. The indications for and techniques of percutaneous reestablishment of surgically placed jejunostomy tubes, the percutaneous conversion of gastrostomy to jejunostomy tubes with retention of the gastrostomy tube, and percutaneous placement of an inferior vena caval Hickman catheter are all described in detail.

Use of computed tomography scanning before and after sitting in an emergency department.

RATIONALE AND OBJECTIVES: Before a computed tomography (CT) scanner was installed in the emergency department, this hospital had no dedicated CT scanner for patients in the emergency department, and transporting these patients to the CT scanners in the radiology department took approximately 8-10 min each way. We sought to determine whether the presence of a CT scanner within the emergency department would lead to an increase in the number of emergent cranial CT examinations and a decrease in the diagnostic yield of these examinations. METHODS: More than 8,000 records of cranial CT examinations were reviewed for the 12 months before and the 12 months after the installation of the CT scanner in the emergency department. A positive case was defined as one that showed acute abnormality such as ischemia, hemorrhage, edema, or mass effect. RESULTS: Our results show a 30.1% increase in the number of CT scans of the head ordered by physicians in the emergency department after the installation of a CT scanner (p < .0001). This is compared with the background 1.8% increase in the total number of emergency department visits. However, in both periods, 12% of the total number of head scans done were positive. CONCLUSION: The convenience of having a CT scanner in the emergency department leads to greater use of CT examinations. However, the increase in the number of emergent CT studies is justified because the number of positive CT examinations increases proportionately.

The appropriate use of contrast venography and pulmonary angiography in the orthopedic population.

Lower-extremity venous thrombosis and its major complication, pulmonary embolism, occur with an increased prevalence in the orthopedic population, even in patients receiving prophylactic therapy. Compression ultrasound has become the diagnostic test of choice to screen high-risk patients and to evaluate symptomatic patients. Contrast venography should be reserved to evaluate the few patients in whom adequate quality ultrasound examinations are unobtainable. Pulmonary angiography remains the "gold standard" in the diagnosis of pulmonary embolism and should be obtained in all patients in whom ventilation-perfusion scan results are discordant with clinical suspicion, and whenever treatment risks are extraordinary.

Percutaneous inferior vena caval filters.

Percutaneous placement of caval filters is performed with increasing frequency as an alternative or adjunctive therapy for venous thromboembolic disease. The stainless steel Greenfield filter may be placed surgically or percutaneously. There are now several other approved or investigational devices primarily intended for percutaneous delivery. Morbidity and mortality rates for percutaneous filter placement are lower than those published for surgical filter placement. Choosing among the various devices on the basis of published studies is difficult, as the indications for filter placement; objectivity of follow-up; and criteria for complications, success, and failure vary greatly among studies. The author analyzes published and unpublished data about the physical characteristics; clinical availability; and morbidity, mortality, and efficacy rates of several caval filters. The author concludes that filters should be placed percutaneously rather than surgically, that the ideal device cannot be determined on the basis of current data (and might not exist), and that the choice among devices might depend on clinical circumstances and device characteristics. A strong recommendation is made for an independent, multicenter, prospective, randomized trial and, in the interim, a mandatory registry of all patients receiving caval filters.

Low dose thrombolysis: a nonoperative approach to renal artery occlusion.

Selective infusion of low dose streptokinase into the occluded renal arteries of 3 patients produced clot lysis. Clot lysis was achieved with a dose of 5,000 units per hour (1/100 systemic dose) when delivered via catheter to the clot site for 24 to 36 hours. No untoward consequences related to bleeding were encountered. In selected patients this technique permits re-establishment of renal arterial patency without surgery.

Use of metallic stents to salvage and maintain patency in surgically created esophagocutaneous fistulas.

The authors report a case in which metallic Gianturco-Rosch stents were used to maintain patency of a surgically created cervical esophagocutaneous fistula. The patient was a young man with a schizoaffective disorder who underwent esophagogastrectomy as a result of multiple suicide attempts with lye ingestion. Surgical reconstruction was not possible due to extensive tissue damage. A surgically created cervical esophagocutaneous fistula allowed drainage of oral secretions but subsequently closed. Metallic Gianturco-Rosch stents were successfully used to maintain patency of this fistulous tract, following balloon dilation of the scarred hypopharynx and the tract, which has remained functional for 10 months.

Percutaneous management of abscesses that involve native arteries or synthetic arterial grafts.

Retrospective analysis of 250 cases in which abscess drainage was performed revealed four abscesses in four patients that were associated with either underlying infected synthetic arterial bypass grafts (n = 3) or an underlying infected native artery (n = 1). Percutaneous drainage of the abscess coupled with intravenous antibiotic therapy resulted in palliation in three patients and possible long-term cure in one patient. No catheter-related complications resulted. In two patients, preoperative abscess sterilization allowed the substitution of alternative revascularization procedures of decreased morbidity and technical complexity. On rare occasions, when emergent surgery is absolutely contraindicated in the setting of graft or arterial infection, percutaneous drainage may play a role in palliative therapy.

Angioplasty sites: assessment with the dual-access technique.

A technique was developed for evaluation of percutaneous transluminal angioplasty sites in arteries arising directly from the aorta. This technique involves the use of a 6-F sheath through which a 4-F pigtail catheter can be placed concurrently with a 0.032-inch guide wire that is left across the dilation site. This allows injection of adequate rates of contrast material while access is maintained, should redilation be necessary.