Pulmonary cysticercus.

Cysticercus cellulosae, the encysted larva of Taenia solium, is reported in a solitary granulomatous lesion excised from the lung of a 61-year-old woman from Thailand. No extrapulmonary signs of cysticercosis were manifest preoperatively, and the diagnosis was not suspected clinically. Pulmonary cysticercus is rarely diagnosed histologically. When unaccompanied by extrapulmonary disease, a single cysticercus lung lesion may be clinically and radiologically indistinguishable from other granulomata and malignancy.

Digital angiographic measurement of radiographic contrast material kinetics for estimation of myocardial perfusion.

We studied the use of digital angiography for the quantification of regional myocardial perfusion in the dog using selective left coronary arterial injection of radiographic contrast material as a flow dilution indicator. We developed algorithms for generating time-intensity curves from regions of interest over the proximal coronary artery and the myocardium and for densitometric error correction by subtraction of the intensity curve over a small lead blocker before logarithmic transformation. The resultant myocardial time-density curves were analyzed for time from injection to peak concentration (TPC) and for exponential washout rate (k). A linear correlation was found between absolute coronary arterial blood flow and both k (slope = 0.13, r = .85) and 1/TPC (slope = 0.18, r = .85). Reproducibility of TPC and k for repeated studies was 11% and 16%. Induced hyperemia significantly improved the sensitivity to stenosis by increasing the average difference in TPC and k between regions served by normal and stenotic coronary arteries to 65% and 80%, respectively. By combining selective coronary arterial injection with the left lateral x-ray projection it was possible to avoid most overlap of regional perfusion beds in the dog. This study suggests that contrast dilution measurements made during digital coronary angiography provide a means for assessing the hemodynamic significance of stenoses and the efficacy of therapeutic interventions.

Digital quantification eliminates intraobserver and interobserver variability in the evaluation of coronary artery stenosis.

A leading problem with subjective interpretation of coronary angiography is high intraobserver and interobserver variability. Four experienced angiographers independently determined percent diameter narrowing of 36 stenoses using 3 methods: by subjective analysis of single-frame cine film images (film), by subjective analysis of digitized nonenhanced single-frame images (digital), and by using a semiautomated digital caliper quantification system (Corona). The reproducibility of interpretations was assessed by comparison of estimated intraclass correlation coefficients. Digital and Corona readings correlated well with subjective interpretation of film (r greater than 0.85 for both). In contrast to Corona, the angiographers systematically overestimated the magnitude of stenoses in the intermediate (50 to 75%) range. Corona markedly improved intraobserver (p less than 0.005) and interobserver (p less than 0.001) reproducibility. Corona less frequently misclassified individual observations than did film when categories of less than 50%, 50 to 75% and more than 75% diameter stenosis were used (3.7% vs 31.5%, p less than 0.001). Our results suggest that digitization of a coronary angiogram in a 512 X 512 matrix has no significant adverse effects on the perception and quantification of stenosis by angiographers. Additionally, automatic measurement of coronary stenosis has 2 major advantages: It is accurate compared with a group of experienced angiographers and for the practical purpose of clinical decision-making, it eliminates intraobserver and interobserver variability.

Coronary spasm: Prinzmetal's variant angina vs. catheter-induced spasm; refractory spasm vs. fixed stenosis.

An analysis of 2,394 selective coronary angiograms yielded 23 examples of coronary artery spasm. Of these, nine occurred in patients with Prinzmetal's variant angina and 14 were instances of catheter-induced spasm. Angiographic criteria can distinguish between the spasm of variant angina and catheter-induced spasm. The latter is usually asymptomatic, almost invariably in the right coronary artery, at the catheter tip, smooth, concentric, and less than 2 mm long. The former can occur in any coronary artery at a distance of 1--4 cm from the catheter tip, is usually irregular and eccentric, and is associated with angina, ST segment elevation, hypotension, and dysrhythmia. Response to nitroglycerin is often, but not always, complete in both. Stenoses that seem to be fixed in patients with Prinzmetal's angina should be suspected to be spasm even if unresponsive to nitroglycerin, especially when the rest of the vessel is normal. Additional pharmacologic manipulation and even recatheterization may be necessary to prove the dynamic nature of the lesion and avoid unnecessary surgery.

Increased cardiac contractility in acute uremia: interrelationships with hypertension.

To study the effects of acute uremia on the inotropic state of the rat heart, we subjected rats to bilateral nephrectomy and studied their hearts in the open chest 24 h later. Uremic rats had significantly higher systolic blood pressure than sham-operated animals. Left ventricular systolic pressure and maximum dP/dt, both during ejection and isovolumic contrations, were higher for any given end-diastolic pressure in hearts of uremic rats than in sham-operated animals. This difference in performance charcteristics was not abolished by doses of propranolol that blocked the heart rate response to isoproterenol. The administration of phenoxybenzamine during the 24 h of uremia abolished the blood pressure rise in uremic rats, but the increased contractile state persisted. Treatment of sham-operated animals with methoxamine to produce the same course of blood pressure as observed in uremic rats was also associated with an increased inotropic state. These results indicate that in the rat, acute uremia is associated with an increased inotropic state that is not mediated by beta-adrenergic mechanisms. The systolic hypertension of acute uremia is not the major cause of the increased contractility, although systolic hypertension without uremia can mimic the performance characteristics found in hearts of uremic rats.