Diagnostic performance of quantitative coronary artery disease assessment using computed tomography in patients with aortic stenosis undergoing transcatheter aortic-valve implantation.

BACKGROUND: Computed tomography angiography (CTA) is a cornerstone in the pre- transcatheter aortic valve replacement (TAVI) assessment. We evaluated the diagnostic performance of CTA and coronary artery calcium score (CACS) for CAD evaluation compared to invasive coronary angiography in a cohort of TAVI patients. METHODS: In consecutive TAVI patients without prior coronary revascularization and device implants, CAD was assessment by quantitative analysis in CTA. (a) Patients with non-evaluable segments were classified as obstructive CAD. (b) In patients with non-evaluable segments a CACS cut-off of 100 was applied for obstructive CAD. The reference standard was quantitative invasive coronary angiography (QCA, i.e. ≥ 50% stenosis). RESULTS: 100 consecutive patients were retrospectively included, age was 82.3 ± 6.5 years and 30% of patients had CAD. In 16% of the patients, adequate visualization of the entire coronary tree (all 16 segments) was possible with CTA, while 84% had at least one segment which was not evaluable for CAD analysis due to impaired image quality. On a per-patient analysis, where patients with low image quality were classified as CAD, CTA showed a sensitivity of 100% (95% CI 88.4-100.0), specificity of 11.4% (95% CI 5.1-21.3), PPV of 32.6% (95% CI 30.8-34.5), NPV of 100% and diagnostic accuracy of 38% (95% CI 28.5-48.3) for obstructive CAD. When applying a combined approach of CTA (in patients with good image quality) and CACS (in patients with low image quality), the sensitivity and NPV remained at 100% and obstructive CAD could be ruled out in 20% of the TAVI patients, versus 8% using CTA alone. CONCLUSION: In routinely acquired pre-TAVI CTA, the image quality was insufficient in a high proportion of patients for the assessment of the entire coronary artery tree. However, when adding CACS in patients with low image quality to quantitative CTA assessment in patients with good image quality, obstructive CAD could be ruled-out in 1/5 of the patients and may therefore constitute a strategy to streamline pre-procedural workup, and reduce risk, radiation and costs in selected TAVI patients without prior coronary revascularization or device implants.

Impact of an endorectal coil for 1H-magnetic resonance spectroscopy of the prostate at 3.0T in comparison to 1.5T: Do we need an endorectal coil?

OBJECTIVES: To evaluate the influence of endorectal coil (ERC) regarding spectral quality and diagnostic suitability and diagnostic performance in 3.0T 1H-magnetic resonance spectroscopy imaging (MRSI) compared to 1.5T MRSI. MATERIALS AND METHODS: The study was approved by the Institutional Review Board. MRSI of the prostate was performed on 19 patients at 1.5T with ERC (protocol 1), at 3.0T with a disabled ERC (protocol 2) and at 3.0T with ERC (protocol 3). Age, weight, body size, body-mass-index, prostate volume, time between measurements, diagnostic suitability of spectra, histopathological results after biopsy of cancer suspect lesions (CSL), sensitivity and specificity were evaluated. Signal-to-noise ratio (SNR) was calculated and compared using semiparametrical multiple Conover-comparisons. Correlations between SNR and prostate volume and BMI were indicated using Pearson correlation coefficient. Distribution of SNR was evaluated for prostate quadrants. RESULTS: Diagnostic suitable spectra were achieved in 76 % (protocol 1, 100% in CSL), 32 % (protocol 2, 59% in CSL) and 50 % (protocol 3, 80% in CSL) of the voxels. SNR was significantly higher in protocol 3 compared to protocol 2 and 1 (93,729 vs. 27,836 vs. 32,897, p<0.0001) with significant difference between protocol 2 and 1 (p<0.023). Highest SNR was achieved in the dorsal prostate (protocols 1 and 3; p<0.0001). Sensitivity at 3.0T was higher with use of ERC. Specificity was highest at 1.5T with ERC. CONCLUSION: The ERC improves the diagnostic suitability and the SNR in MRSI at 3.0T. Less voxels at 3.0T with disabled ERC are suitable for diagnosis compared to 1.5T with ERC. MRSI at 3.0T with ERC shows the highest SNR. SNR in dorsal quadrants of the prostate was higher using ERC.