Multislice CTA excels in diagnosis of lower extremity disease

Published clinical studies are expanding the diagnostic limits of multislice CT and other modalities for cardiovascular applications. A meta-analysis in the November Radiology offers a powerful argument in favor of its use for diagnosing lower extremity disease. Other, more preliminary, studies suggest that multislice and dual-source CT will eventually help evaluate in-stent restenosis and the quantification of left ventricular function. New applications are emerging for cardiac MR, echocardiography, and PET/CT as well.

Lower extremity arterial disease

Lower extremity arterial disease: multidetector CT angiography meta-analysis

Radiology 2007 245: 433-439

With pooled sensitivity and specificity rates of 92% and 93% respectively, multislice CTA was found to be highly accurate for diagnosing arterial disease of the entire lower extremity. The conclusion is based on a meta-analysis of 70 studies involving 9541 arterial segments and 436 patients. Majanka H. Heijenbrok-Kal, Ph.D., and colleagues at Erasmus Medical Center in Rotterdam, the Netherland conducted the evaluation.

In-stent restenosis

Evaluation of patients with previous coronary stent implantation with 64-section CT

Radiology 2007 245: 416-423

Sixty-four slice CT angiography may be useful for noninvasively excluding the presence of in-stent or peristent restenosis, according to this study by Dr. Joanne D. Schuijf and colleagues at Leiden University Medical Center in the Netherlands. Sixty-five of 76 stents (86%) were deemed assessable in this study of 50 patients. Partially overlapping stents were counted as one; seven stents overlapped each other, meaning 58 were evaluated. A high heart rate and overlapping positioning were the main reasons imaging of the stents was deemed not interpretable. Multislice CT correctly identified significant restenosis, of greater than 50%, in six stents and the absence of significant restenosis (less than 50%) in the remaining 52. Sensitivity and specificity for the detection of significant peristent stenosis were 100% and 98% respectively.

Left ventricular function

Dual-source CT with improved temporal resolution in assessment of left ventricular function: a pilot study

AJR 2007; 189: 1064-1070

A pilot study involving 20 patients - 15 of whom had a previous myocardial infarction - demonstrated that dual-source CT accurately measures global left ventricular function and reliably evaluates regional wall motion. Dr. Harald Brodoefel and colleagues at Eberhard-Karls University in Tuebingen, Germany, found a strong correlation between dual-source CTA and cine MRI quantification of end-diastolic volume, end-systolic volume, stroke volume, and ejection fraction, with r scores ranging from 0.95 to 0.97. Good correlations were established for peak ejection rates (r = 0.79) and peak filling rate (r = 0.84), and moderate correlations between the two modalities were measured for time-to-peak ejection rate (r = 0.68) and time-to-peak filling rate from end systole (r = 0.64).

Ventricular tachycardia

Enhanced infarct border zone function and altered mechanical activation predict inducibility of monomorphic ventricular tachycardia in patients with ischemic cardiomyopathy

Radiology 2007; 245:712-719

Working in the laboratory of Dr. João Lima at Johns Hopkins Hospital, Dr. Veronica Rolim S. Fernandes and colleagues determined from contrast-enhanced cardiac MR studies of 46 patients with prior myocardial infarction and left ventricular dysfunction that specific distances of scar tissue from infarcted and noninfarcted myocardium can predict the inducibility of monomorphic ventricular tachycardia. Inducible patients had more infarcted and border zone sectors and a shorter time to peak circumferential shortening strain than noninducible patients in the border zone and adjacent and infracted regions (pRight ventricular wall motion

Role of right ventricular wall motion abnormalities in risk stratification and prognosis of patients referred for stress echocardiography

J Am Coll Cardiol 2007; 50:1981-1989

Dr. Sripal Bangalore and colleagues in the cardiology division of St. Luke's-Roosevelt Hospital in New York found from an evaluation of 2703 patients referred for stress echocardiography that right ventricular wall motion has prognostic value independent of left ventricular ischemia and ejection fraction in assessing cardiac risk. The right ventricle was evaluated using a three-segment five-point scale for wall motion abnormalities. Follow-up was performed an average of 2.7 years later (+/- 1.0 years) to confirm myocardial infarction and cardiac death. Abnormal RV wall motion was detected in 112 patients (4%). The data were determined to provide incremental value over rest and conventional stress echo studies. Bangalore recommended the routine performance of right ventricular wall motion analysis for cardiac risk stratification.

Ischemic heart disease

Relationship between CT coronary angiography and stress perfusion imaging in patients with suspected ischemic heart disease assessed by integrated PET-CT imaging

J Nuc Cardiology 2007;14(6):799-809

A study of 110 consecutive patients with suspected coronary artery diseases at Beth Israel Medical Center documented the strengths and weakness of multislice CTA and PET/CT perfusion imaging. Despite negative predictive values in the 97% range, 64-slice CTA was judged as a poor discriminator of patients with myocardial ischemia. Conversely, normal stress rubidium-82 perfusion performed poorly when discriminating patients with evidence of non-flow-limiting coronary atherosclerosis. The results, reported by nuclear medicine chair Dr. Marcelo Di Carli and colleagues, suggest that the two approaches would work well together.