Duplex ultrasonography criteria for internal carotid stenosis of more than 70% diameter: angiographic correlation and receiver operating characteristic curve analysis.

OBJECTIVE: To determine duplex ultrasonography criteria for detecting stenosis of 70% or more in the internal carotid artery, to be used as a means of selecting candidates suitable for endarterectomy (a procedure suggested by the North American Symptomatic Carotid Endarterectomy Trial as appropriate for symptomatic patients with 70% to 99% stenosis). PATIENTS AND METHODS: Between Jan. 1, 1991, and Apr. 30, 1993, 120 patients underwent internal carotid angiography at a tertiary care hospital for transient ischemic attacks, asymptomatic bruits or preoperative assessment. Of these, 83 also underwent duplex ultrasonography within 31 days of angiography. The angiographic and sonographic studies for 145 vessels in 75 of the patients (50 men and 25 women) were suitable for further study. The sonographic criteria were selected on the basis of a receiver operating characteristic curve relating peak systolic velocity of the internal carotid artery to the degree of stenosis determined angiographically. RESULTS: Angiography indicated that 33 of the vessels had stenosis of 70% or more and that 12 additional vessels were completely occluded. The combined sonographic criteria of peak systolic velocity of less than 40 cm/s or 175 cm/s or more yielded 91% sensitivity and 60% specificity for angiographically determined stenosis of 70% or more. CONCLUSION: In this patient population the combined criteria of peak systolic velocity of less than 40 cm/s or 175 cm/s or more were highly sensitive and reasonably specific for internal carotid artery stenosis of 70% or more.

Ascending aortic dissection causing unilateral absence of perfusion on lung scanning.

A case of an ascending aortic dissection occurring in a patient 8 years after an aortic valve replacement is presented. The patient's initial clinical presentation was thought to be due to pulmonary embolism, and a ventilation-perfusion lung scan demonstrated mismatched absence of perfusion to the entire right lung. Aortography and findings at surgery demonstrated a type A dissection of the ascending aorta. The anatomic relationship of the aorta and pulmonary artery and their common tunica adventitia make the right pulmonary artery susceptible to extrinsic compression after aortic dissection. Although uncommon, dissection of the ascending aorta needs to be considered in patients who have undergone previous aortic valve surgery and demonstrate mismatched unilateral absence of perfusion to the right lung. Because anticoagulation is contraindicated in patients with acute aortic dissection, confirmation of the diagnosis with angiography usually is required.

Atherectomy. Early use of three different methods.

The authors report their initial experience in 52 patients with three different techniques of peripheral artery atherectomy--the Tracwright (Kensey), used in 19 patients, the Simpson AtheroCath, used in 19 patients and the transluminal extraction catheter, used in 14 patients. The indications for atherectomy were claudication in 42 (80%) and limb-threatening ischemia in 10 (19%). There were no deaths. Complications included three arterial perforations, one thrombosis and one groin hematoma requiring operative evacuation. There were no distal embolizations. Atherectomy was initially unsuccessful in 15 (29%) patients. For the successfully completed procedures, the 1-year primary patency rates were as follows: Tracwright (Kensey) catheter 56%, Simpson catheter (63%) and transluminal extraction catheter (0%). Use of subsequent nonoperative procedures on recurrent stenoses produced secondary patency rates of 77% for the Tracwright (Kensey) technique, 80% for the Simpson catheter technique and 78% for the transluminal extraction catheter technique. The authors conclude that their early results justify further evaluation of these three techniques. Use of the transluminal extraction catheter is associated with higher rates of occlusion and restenosis.

Testicular microlithiasis: sonographic and clinical features.

Eleven cases of bilateral diffuse microlithiasis of the testes were evaluated sonographically. The presence of testicular microlithiasis was coincidental to the presence of testicular neoplasms (n = 2), nontesticular malignant lesion in the abdomen or chest (n = 2), subfertility (n = 2), varicocele (n = 1), epididymitis (n = 1), testicular maldescent (n = 1), scrotal trauma (n = 1), and transient scrotal pain (n = 1). Clinical follow-up suggested that testicular microlithiasis is an asymptomatic nonprogressive condition. Sonographic examination of testicular microlithiasis shows diffuse hyperechoic nonshadowing foci measuring 1-2 mm in diameter throughout both testes. The diagnosis of testicular microlithiasis was pathologically proved in five cases. In six cases, the diagnosis was made on the basis of the sonographic appearance (n = 6), clinical information and follow-up (n = 6), and radiologic demonstration of testicular microcalcifications (n = 3). The sonographic appearance of testicular microlithiasis is specific, and we believe that biopsy or orchiectomy in these cases is unnecessary.

Thrombus-trapping efficiency of the LGM (Vena Tech) and titanium Greenfield filters in vivo.

To assess the trapping efficiency of two vena cava filters, 326 radiopaque thrombi 5 mm in diameter were injected into adult sheep: four with LG-Medical (LGM) and four with titanium Greenfield (TG) filters. Thrombi were sequentially injected and not removed. Trapping was monitored fluoroscopically, and the pressure gradient across the filter was measured. The LGM filter trapped 70% of 5 x 5-mm and 100% of 5 x 10-mm thrombi; the TG, 26% of 5 x 5-mm, 34% of 5 x 10-mm, and 37% of 5 x 30-mm thrombi. The LGM filter required an average of 2.0 mL of trapped thrombus to occlude the filter, compared with 6.4 mL for the TG. These differences were statistically significant. These data indicate that in this model, the LGM filter traps thrombi more efficiently than the TG filter but is more likely to produce caval occlusion.

LGM (Vena Tech) vena cava filter: clinical experience in 64 patients.

LG-Medical (LGM) vena cava filters were inserted percutaneously in 64 patients. Each case was followed after the filter insertion. Clinical follow-up was available in all patients; in 11 patients it was the only form of follow-up. Findings were available from autopsies in seven patients, plain abdominal radiographs in 42, and duplex sonograms of the insertion vein and inferior vena cava (IVC) in 46. A filter was inserted without major complication in all patients. The filter failed to open fully in four patients and was tilted in the IVC in 15. Recurrent pulmonary embolism was found in two patients (fatal in one), and inconsequential filter migration occurred in 11. Introduction vein thrombosis occurred in four patients. IVC thrombosis, demonstrated at autopsy or sonography, was found in 14 patients (22%) and was symptomatic in six (9%). This report suggests that the LGM filter is easy to introduce, and few complications are associated with insertion. The rate of caval thrombosis, however, may be higher than previously reported.

Outpatient transfemoral angiography with a two-hour observation period.

A study was undertaken to determine whether reducing needle size would reduce the complication rate of outpatient angiography with 4F catheters. One hundred fifty-two patients were randomized. An 18-gauge needle was used in 51, a 20-gauge in 50, and a 21-gauge in 51. Patients were observed for 2 h. No patients deteriorated after discharge. None of the 18-gauge patients developed a hematoma. Four percent of the 20-gauge and 2% of the 21-gauge patients had mild hematomas. This suggests that outpatient angiography using 4F catheters and 2 h of observation is safe. Increased safety with 20 or 21-gauge needles was not confirmed.

Hepatic hemangioma in the presence of fatty infiltration: an atypical sonographic appearance.

The typical hepatic cavernous hemangioma presents no diagnostic difficulty at sonography. In contrast, an atypical hemangioma may cause great concern and result in costly and time-consuming investigations. The presence of diffuse fatty infiltration may result in an atypical echo-poor appearance of the hemangioma. Under such circumstances, computed tomography (CT) may not allow definitive diagnosis and magnetic resonance imaging (MRI) may be necessary.