Adrenocortical tumor with left renal vein, vena cava and intrahepatic venous extension.

A 41 year old white female presented with upper respiratory distress and shortness of breath appeared on initial computed tomography (CT) scan to have a large left retroperitoneal mass with left renal vein extension including a mass up to the level of the atrium. This presentation suggested hypernephroma. She proved, however, to have an adrenal cortical carcinoma which displaced the kidney, exhibiting vascular invasion within the gland and non-adherent extension into the vena cava, atrium, common hepatic vein and left renal vein, where some adherence was present. This unusual tumor required extensive surgery for removal, including use of cardiopulmonary bypass, with good results.

Venous bypass of complicated stent placement for recurrent extracranial carotid occlusive disease.

Aim of the study was to to demonstrate a useful solution to carotid angioplasty and stent complications. A 67 year old male had uncomplicated left carotid endarterectomies in 1985 and 1986. A left distal common carotid angioplasty and stent in 1999 was complicated by stenosis. In 2000 a left common carotid bypass from the lower common carotid to the distal internal carotid well above the stent was performed, yielding retrograde filling of the external carotid, distal antegrade filling of the internal carotid, and widely patent vessels in subsequent Doppler studies. He is currently doing well clinically with no recurrent stenosis. In conclusion a second redo carotid operation was deferred in favor of angioplasty and stent, which had complications. Despite prior operations the only difficulty with the reoperation was obtaining control of the distal internal carotid above the stent. The strategy demonstrated here will be useful to correct complications of carotid angioplasty and stenting.

A gentle introduction to knowledge-based systems in medicine.

In summary, AI expert systems, through the example of medical problem solving, have been examined, considering goals, problems addressed, and problems resolved (or not resolved). How these systems attempt to replicate the knowledge and strategies of human experts has been shown, as well as how they determine these factors (in the form of the protocol). Through the example of diagnosis, some of the types of knowledge and approaches such systems must encode have been illustrated. Concrete examples of approaches to encoding were presented using MYCIN and PIP. These systems demonstrate more clearly the complexity of the problem domains under consideration, how that complexity can be dealt with, and the limitations and potential of AI. It is apparent that such systems have unique contributions to make, not only in terms of straightforward usefulness but also in terms of inspectability, which may be extended to a capacity for "explaining." On a more basic level, they are generating a reexamination of what is considered "intelligent" behavior--which may itself lead to future concepts, systems, and tools. Moreover, the fundamental goal of generality in the design of AI systems makes such things as, for example, the hypothetico-deductive model of behavior transferrable across domains, conferring a similar ability for revitalization and reexamination in each one.