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.

Percutaneous revascularization of complex iliac artery stenoses and occlusions with use of Wallstents: three-year experience.

PURPOSE: To assess the outcome of percutaneous placement of Wallstents for treatment of hemodynamically significant diffuse stenoses (> 3 cm in length), chronic occlusions, failed angioplasty procedures, and flow-limiting dissection in the iliac arteries. MATERIALS AND METHODS: Lesions in 94 iliac limbs were treated in 66 patients. Indications for stent placement included claudication in 49 limbs and limb-threatening ischemia in 45. Forty-two limbs were treated for diffuse disease, 39 for chronic occlusion, nine for failed angioplasty, and four for flow-limiting dissection. RESULTS: Technical success was achieved in 86 of 94 limbs (91%), with major complications in 9% of patients. One death occurred within 30 days (not procedure-related). Ankle-brachial indexes improved from 0.51 +/- 0.24 to 0.76 +/- 0.22 (P < .001). Eighty-five percent demonstrated improvement under Rutherford criteria. Follow-up was obtained up to 38 months (mean, 14 months +/- 8). Cumulative primary patency rates were 78% at 1 year and 53% at 2 and 3 years (standard error 10%). Secondary patency rates were 86% at 1 year and 82% up to 32 months (standard error > 10% after 32 months). No significant decrease in mean ankle-brachial index was observed during follow up. No difference in primary patency was observed based on lesion type, symptom severity, lesion location, or runoff status. The limb salvage rate for patients with limb-threatening ischemia was 98% at a mean follow-up of 14 months +/- 7. CONCLUSIONS: Technical success and complication rates for percutaneous iliac artery revascularization with use of Wallstents are favorable, symptoms improved in the majority of patients, and excellent secondary patency can be achieved. With use of Wallstents, most patients with iliac artery insufficiency as a result of long-segment disease or chronic occlusions can be treated percutaneously.

Is bilateral lower extremity compression sonography useful and cost-effective in the evaluation of suspected pulmonary embolism?

OBJECTIVE: Because deep venous thrombosis is clinically linked with pulmonary embolism and often treated similarly, we sought to assess the usefulness of obtaining bilateral lower extremity compression sonograms when findings on ventilation-perfusion lung scans indicate a low or indeterminate probability of pulmonary embolism. Demonstration of deep venous thrombosis would provide a rationale for treating both pulmonary embolism and deep venous thrombosis. MATERIALS AND METHODS: Two hundred twenty-three consecutive patients with suspected pulmonary embolism had ventilation-perfusion lung scans and concurrent bilateral lower extremity compression sonograms; 34 also had pulmonary arteriography. RESULTS: In 75 cases, the results of ventilation-perfusion lung scanning indicated an indeterminate probability of pulmonary embolism. Evidence of thrombosis was seen on sonograms in 11 of these 75. In the remaining 64, 17 underwent pulmonary arteriography and four (24%) had pulmonary embolism. Findings on lung scans indicated a low probability of pulmonary embolism in 70 of 223 patients. Evidence of thrombosis was seen on sonograms in 11 of these 70. Five of the remaining 59 underwent pulmonary arteriography and one (20%) had pulmonary embolism. According to the 1993 Medicare Fee Schedule, if all 145 patients whose lung scans were nondiagnostic had sonography and only those with normal sonograms had pulmonary arteriography, the professional and hospital charges would be $359,552. If all 145 had pulmonary arteriography without sonography, the charges would be $395,031. CONCLUSION: If ventilation-perfusion lung scans indicate a low or an indeterminate probability of pulmonary embolism and bilateral lower extremity compression sonography is performed, only those patients with normal sonographic findings would need further study. Thus, 15% (22/145) of patients could be spared pulmonary arteriography, and the estimated savings in cost would be 9%.

Use of preprocedural tests by interventional radiologists.

A direct survey was taken of 1,238 members of the Society of Cardiovascular and Interventional Radiology (SCVIR) concerning the routine use of 14 tests (most frequently, prothrombin and partial thromboplastin times, complete blood cell counts, and blood urea nitrogen and serum creatinine levels) performed before 10 invasive percutaneous procedures (peripheral angiography, neuroangiography, transluminal angioplasty, thrombolysis, percutaneous needle biopsy, abscess drainage, percutaneous nephrostomy, biliary drainage, myelography, and venography). The survey was undertaken to determine the current practices and appropriateness of current routine use of preprocedural tests. The response rate was 34%, representing a cumulative annual volume of 322,208 cases. The practice of performing routine preprocedural tests is common among interventional radiologists. Data provided by this survey suggest that use of these tests is excessive. Adherence to suggested proposals derived from previously reported experience would result in an annual estimated savings of $20.0-$34.9 million (extrapolated for all procedures performed by SCVIR members in 1989).

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.

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.

Percutaneous drainage of 335 consecutive abscesses: results of primary drainage with 1-year follow-up.

Retrospective review of percutaneous abscess drainage (PAD) of 335 abscesses in 323 consecutive patients was undertaken. Particular attention was directed to body location, associated organ system, communications and fistulae, and to the underlying immunologic status of the patient. One-year follow-up was available in all patients. Overall, the cure rate was 62.4% (209 of 335 abscesses), with a failure rate of 8.95% (30 of 335 abscesses). There were 14.2% (46 of 323 patients) deaths in the follow-up period, of which 4.6% (15 of 323 patients) were believed attributable to sepsis or septic complications. The overall complication rate was 9.8% (33 of 335 abscesses), most of which were minor in nature. For the patient exhibiting immunocompromise, representing 53.1% (172 of 323 patients) of the patient population, the cure rate was 53.4% (95 of 178 abscesses), which was significantly lower than the cure rate of 72.6% (114 of 157 abscesses) for the immunocompetent patient population (n = 151) (P less than .001). The recurrence rate was 2.1% (seven of 335 abscesses), with all recurrences within 3 months of initial drainage. PAD is effective and permanent treatment for both immunocompromised and immunocompetent patients.

Prebiopsy wire localization of a small peripheral lung nodule.

The authors report a case in which metallic microcoils were placed under computed tomographic guidance as wire localization devices prior to an excisional lung biopsy. The technique and advantages are somewhat analogous to those of pre-excisional biopsy of a breast mass with use of wire localization performed under mammographic guidance. This technique was useful for localizing the mass as well as limiting the amount of surgically excised tissue in this case. Additionally, the postexcision specimen radiograph helped confirm that the lung lesion in question had been removed. This may be a useful preoperative technique prior to excisional biopsies of small lung lesions that may not be accessible with percutaneous biopsy techniques and in selected cases such as in patients with diseased lung parenchyma surrounding a lesion or in patients in whom the lesion to be excised is adjacent to the pulmonary root.

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.

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 drainage of hepatic abscesses: comparison of results in abscesses with and without intrahepatic biliary communication.

Results of percutaneous drainage performed in eight patients with eight liver abscesses with intrahepatic biliary communication and 22 patients with 26 liver abscesses without biliary communication were analyzed to determine whether the presence of an intrahepatic biliary communication affected the outcome of treatment. The clinical features and response to treatment of both groups were compared. The presence or absence of biliary communication was determined by injection of contrast material into the abscess under fluoroscopic guidance either during or several days after initial drainage. Duration of drainage was longer (p less than .05) in patients with communication (range, 7-44 days; mean, 22 days) than in patients without communication (range, 1-33 days; mean, 13 days). Percutaneous drainage was curative in five (63%) and palliative or temporizing in one (13%) of eight patients with communication. It was curative in 15 (68%) and palliative or temporizing in five (23%) of 22 patients without communication (p = .317). Liver abscesses with intrahepatic biliary communication did not require percutaneous transhepatic biliary diversion for cure. Despite longer duration of drainage for abscesses with intrahepatic biliary communication, the cure rates of percutaneous drainage for both groups were similar. Patients in whom an intrahepatic biliary communication was shown did not require alternative interventional or surgical measures for cure.

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.