Colour-assisted compression ultrasound in the diagnosis of calf deep venous thrombosis.

OBJECTIVE: To determine sensitivity and specificity of colour-assisted compression ultrasound (CUS) in the diagnosis of deep venous thrombosis (DVT) isolated to the calf veins. DESIGN: Prospective comparison of CUS with contrast venography in patients undergoing both procedures, with blinded evaluation of results. SETTING: Alfred Hospital, Melbourne (an urban tertiary referral hospital), between November 1990 and May 1992. SUBJECTS: Patients presenting for contrast venography with signs or symptoms of lower limb DVT. OUTCOME MEASURES: Presence of DVT; technical adequacy of examination. RESULTS: 92 of 402 patients (104 limbs) were examined. DVT was detected by venography in 43 limbs and was isolated to the calf veins in 19. It was diagnosed by CUS for eight of these 19. Calf CUS was technically inadequate in 26 limbs. Sensitivity and specificity of CUS for isolated calf DVT were 67% (95% confidence interval [CI], 40%-94%) and 93% (95% CI, 83%-100%), respectively, when the CUS was adequate. The low sensitivity of CUS was related to small size of the thrombi, inadequate studies because of previous DVT or very swollen limbs and technical errors. CONCLUSION: CUS is accurate for detecting larger isolated calf DVT when the calf study is adequate. Including the calf veins as well as the femoropopliteal veins in the initial CUS examination for symptomatic suspected lower limb DVT may reduce the need for follow-up CUS.

Comparison of ultrasound and blood pool scintigraphy in the diagnosis of lower limb deep venous thrombosis.

We report a prospective, blinded comparison of compression ultrasound (US) and Tc-99m erythrocyte-labelled venous blood pool scintigraphy (BPS) in patients presenting with symptoms of deep venous thrombosis (DVT). Contrast venography (CV) was used as the gold standard. Ninety-eight lower limbs of 76 patients were examined. DVT was present at CV in 38 of 98 limbs and was isolated to the calf veins in eight. Sensitivity and specificity of ultrasound for femoropopliteal thrombus were 81.5% and 96% and of venous blood pool scintigraphy were 55% and 96%. For deep venous thrombosis in the whole limb sensitivity and specificity of ultrasound were 74% and 90% and of venous blood pool scintigraphy were 61% and 88%. In the calf sensitivity and specificity of US were 61% and 94% and of venous blood pool scintigraphy were 61% and 89%. Excluding equivocal venous blood pool scintigraphy results, the predictive values of a positive and negative venous blood pool scintigraphy study for the whole limb were 84% and 86%. The predictive values of a positive and negative ultrasound where the examination was adequate were 82% and 86%. US is a more sensitive alternative to CV than BPS for femoropopliteal DVT. When neither US nor CV can be performed, BPS remains a useful initial test for DVT, provided it is unequivocally positive or negative.

Perimesencephalic subarachnoid haemorrhage: negative angiography and favourable prognosis.

The computed tomography (CT) scans of 110 consecutive patients who presented, over a 4.5-year period, following spontaneous subarachnoid haemorrhage (SAH), were reviewed. All 110 patients also had one or more 4-vessel digital subtraction cerebral angiograms. The CT scans were reviewed in each case without knowledge of the angiographic result. In nine patients (8%), SAH was confined to the perimesencephalic area, interpeduncular cistern and/or prepontine region at CT. All nine patients had at least two, and some as many as four, negative cerebral angiograms. Eighteen of the 110 patients (16%) ultimately had negative angiography. Hence, the patients with isolated perimesencephalic haemorrhage (PMH) accounted for 50% of the negative angiograms. There was a significant association between isolated PMH and negative angiography (chi 2 = 50.1, P < 0.005). The specificity of PMH for negative angiography was 100% (95% confidence interval (CI) = 97-100%) and the sensitivity of PMH for a negative study was 50% (95% CI = 16-84%). Six of the 110 patients had basilar artery aneurysms demonstrated angiographically as the cause of their SAH but none of these six had isolated PMH at CT. All patients with isolated PMH were alive and well at follow up and none had suffered repeat SAH or vasospasm-related ischaemic cerebral injury. Perimesencephalic haemorrhage should be distinguished from SAH in general, because of the good prognosis associated with it and the doubtful need for repeat cerebral angiography after an initial negative study.

Excimer laser angioplasty in the atherosclerotic rabbit: comparison with balloon angioplasty.

The early and late results of excimer laser angioplasty and balloon angioplasty were compared in atherosclerotic rabbit iliac arteries. Immediately after laser angioplasty (n = 13) with a bare 600 microns fiber, there was a 33% increase in angiographically measured minimum lumen diameter; after balloon angioplasty (n = 12), there was a 53% increase. Restenosis (defined as loss of at least 50% of the gain achieved by angioplasty) occurred in none of six laser-treated rabbits studied 1 month later, compared with four of six balloon-treated rabbits (p = 0.06). Planimetric measurements of cross sections of the arterial wall 1 month after angioplasty showed less intimal and medial tissue in laser-treated (1.8 +/- 0.2 mm2) than in the balloon-treated rabbits (3.0 +/- 0.4 mm2; p less than 0.05). Typical thermal effects were absent on microscopic examination of laser angioplasty sites. It is concluded that in this animal model, excimer laser irradiation results in an immediate increase in lumen diameter comparable with balloon angioplasty, but is associated with less residual atheromatous tissue than balloon angioplasty and a trend toward a lower rate of restenosis.

Arteriographic complications in the DSA era.

Prospective data were collected on complications associated with intraarterial digital subtraction angiography in 2,475 consecutive patients at a 650-bed Melbourne teaching hospital. Carotid or cerebral studies were performed in 939 patients, and the prevalence of stroke (ie, permanent neurologic deficit) was 0.3%. The overall prevalence of systemic complications was 1.8%, with no patients requiring hemodialysis because of renal failure. Comparison was made with previously reported complication rates for conventional film angiography.

Outpatient myelography with iohexol and iopamidol; pilot study and contrast trial.

50 patients underwent myelography on an outpatient basis; the incidence and severity of side effects were compared, in a prospective study, with 180 inpatient examinations over the same period. In addition, in the initial 200 myelograms (36 outpatients and 164 inpatient) iohexol and iopamidol were compared in a double blind trial. Headache was the most common side effect in both patient groups, recorded in 50% of outpatients and 25% of inpatients. Other side effects were of comparable incidence. 84% of outpatients undergoing myelography found it "acceptable", and did not consider a night in hospital necessary after the procedure. No difference in side effects was demonstrated between the two contrast media. This pilot study suggests that outpatient myelography is practical and safe, with considerable cost saving implications.