Management of mammographic indeterminate lesions. First place winner of the Conrad Jobst Award in the Gold Medal paper competition.

The positive predictive value of mammography in nonpalpable malignancy, only 20 to 25 per cent, could be improved with better mammographic criteria for lesions not requiring biopsy. The outcomes of 89 patients with indeterminate lesions were reviewed to determine whether these lesions could be managed safely by observation rather than biopsy. Indeterminate lesions were defined as 1) tightly clustered, nonlinear calcifications (> 5 within 1 cm of tissue); 2) dominant, well-circumscribed soft-tissue masses (< or = 1 cm2); or 3) asymmetric density. Lesions not immediately undergoing biopsy were followed with frequent-interval mammography. Twenty-two lesions (26%) underwent immediate biopsy, and 2 of these demonstrated carcinoma in situ with microinvasion. Sixty-seven lesions (74%) were observed (median follow-up, 34 months), and 2 (2.5%) proved to be malignant, for an overall malignancy rate of 4.5 per cent. All malignancies were stage I, and the patients remain alive with no evidence of disease (average follow-up, 24 months). Sixty patients were spared unnecessary biopsy, decreasing potential wire-directed biopsies by 25 per cent. The positive predictive value of mammography increased from 21 to 32 per cent over the period. Indeterminate lesions can be safely followed with frequent ipsilateral mammography, reserving biopsy for lesions that progress. Management schemes such as this one can be used to decrease the number of negative wire-directed biopsies.

Angiographic evidence of basilar artery constriction in the rabbit: a new model of vasospasm.

The main objective of this study was to produce angiographic evidence of basilar artery constriction using the rabbit model. The technique described involves the transdural injection of blood into the cisterna magna on two different days. The results obtained show that vasoconstriction occurs over a time period that is comparable in duration to that seen in patients undergoing vasospasm as a result of subarachnoid hemorrhage. Further investigation should be done to evaluate the usefulness of the rabbit model as a verifiable tool in studying the etiology of vasospasm.

High-flow angiopathy: cerebral blood vessel changes in experimental chronic arteriovenous fistula.

Profound vascular damage secondary to high-flow extracranial states has been well characterized. However, changes in cerebral vasculature secondary to high-flow states have not been studied. To determine changes related to high-flow states in cerebral vessels, a rabbit model was developed in which torrential flow was created in the vertebrals, carotids, basilar, and vessels of the circle of Willis by means of a carotid-jugular shunt after ligation of the proximal carotid. The clinical, angiographic, and histologic changes noted in the animal model include: abrupt clinical deterioration after a variable interval with some animals developing ptosis, afferent vessel dilatation and the development of prominent anastomotic channels, variable cerebral vessel histopathology--related to duration and relative proximity to the shunt--affecting all three vessel layers, plump, irregular, and clumped endothelium, denuded with adherent platelets, irregular, duplicated, and thinned internal elastic membrane, frayed with invasion of the intima by mesenchymal cells, vacuolization and necrosis of the media muscle, and invasion of adventitia by foreign cells and small blood vessels. The high-flow angiopathy seen in this model may help explain vascular changes associated with high-flow cerebral vascular lesions, as well as other types of vascular damage.