Image quality and diagnostic accuracy of unenhanced SSFP MR angiography compared with conventional contrast-enhanced MR angiography for the assessment of thoracic aortic diseases

The purpose of this study was to determine the image quality and diagnostic accuracy of three-dimensional (3D) unenhanced steady state free precession (SSFP) magnetic resonance angiography (MRA) for the evaluation of thoracic aortic diseases. Fifty consecutive patients with known or suspected thoracic aortic disease underwent free-breathing ECG-gated unenhanced SSFP MRA with non-selective radiofrequency excitation and contrast-enhanced (CE) MRA of the thorax at 1.5 T. Two readers independently evaluated the two datasets for image quality in the aortic root, ascending aorta, aortic arch, descending aorta, and origins of supra-aortic arteries, and for abnormal findings. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were determined for both datasets. Sensitivity, specificity, and diagnostic accuracy of unenhanced SSFP MRA for the diagnosis of aortic abnormalities were determined. Abnormal aortic findings, including aneurysm (n = 47), coarctation (n = 14), dissection (n = 12), aortic graft (n = 6), intramural hematoma (n = 11), mural thrombus in the aortic arch (n = 1), and penetrating aortic ulcer (n = 9), were confidently detected on both datasets. Sensitivity, specificity, and diagnostic accuracy of SSFP MRA for the detection of aortic disease were 100% with CE-MRA serving as a reference standard. Image quality of the aortic root was significantly higher on SSFP MRA (P < 0.001) with no significant difference for other aortic segments (P > 0.05). SNR and CNR values were higher for all segments on SSFP MRA (P < 0.01). Our results suggest that free-breathing navigator-gated 3D SSFP MRA with non-selective radiofrequency excitation is a promising technique that provides high image quality and diagnostic accuracy for the assessment of thoracic aortic disease without the need for intravenous contrast material

Does dual-energy CT of lower-extremity tendons incur penalties in patient radiation exposure or reduced multiplanar reconstruction image quality?

ObjectiveThe purposes of this study were to evaluate the quality and radiation exposure of data acquired with dual-energy CT compared with single-energy MDCT in the depiction of lower-extremity tendons and to assess whether a dual-energy CT voltage exists at which the quality of tendon depiction is optimal.Subjects and methodsEleven healthy volunteers and seven clinically referred patients (10 men, eight women; mean age, 43.1 years; range, 20-71 years) underwent conventional single-energy CT and dual-energy CT examinations of both lower extremities with a dual-source CT scanner. Dual-energy reconstructions were made at combined tube voltages approximating 86, 98, 110, 122, and 134 kVp. Quantitative and qualitative analyses were performed on six tendons in each lower extremity, and the findings were compared with single-energy CT findings. The radiation dose involved was recorded in each case.ResultsA trend toward increasing tendon attenuation was observed with increasing reconstructed tube voltage. The group of single-energy CT reconstructions proved significantly superior to each of the dual-energy CT reconstructions with regard to signal-to-noise ratio (F = 35.25, p < 0.0001) and contrast-to-noise ratio (F = 37.19, p < 0.0001), although interobserver agreement in subjective ranking was poor. Dual-energy CT had a significantly higher radiation dose (p < 0.05) than single-energy CT.ConclusionDual-energy CT of lower-extremity tendons, irrespective of the reconstruction tube voltage chosen, yields multiplanar reformations inferior to those of single-energy CT with regard to signal-to-noise and contrast-to-noise ratios while involving significantly escalated patient exposure to ionizing radiation. Whether the tissue-differentiating promise of dual-energy CT is realized in future studies and warrants such concessions remains to be seen

Data from: Prevalence of coronary artery disease evaluated by coronary CT angiography in women with mammographically detected breast arterial calcifications

To assess the correlation between breast arterial calcifications (BAC) on digital mammography and the extent of coronary artery disease (CAD) diagnosed with dual source coronary computed tomography angiography (CTA) in a population of women both symptomatic and asymptomatic for coronary artery disease. 100 consecutive women (aged 34 – 86 years) who underwent both coronary CTA and digital mammography were included in the study. Health records were reviewed to determine the presence of cardiovascular risk factors such as hypertension, hyperlipidemia, diabetes mellitus, and smoking. Digital mammograms were reviewed for the presence and degree of BAC, graded in terms of severity and extent. Coronary CTAs were reviewed for CAD, graded based on the extent of calcified and non-calcified plaque, and the degree of major vessel stenosis. A four point grading scale was used for both coronary CTA and mammography. The overall prevalence of positive BAC and CAD in the studied population were 12% and 29%, respectively. Ten of the 12 patients with moderate or advanced BAC on mammography demonstrated moderate to severe CAD as determined by coronary CTA. For all women, the positive predictive value of BAC for CAD was 0.83 and the negative predictive value was 0.78. The presence of BAC on mammography appears to correlate with CAD as determined by coronary CTA (Spearman’s rank correlation coefficient = 0.48, p<.000001). Using logistic regression, the inclusion of BAC as a feature in CAD predication significantly increased classification results (p=0.04)