Photon-counting CT-angiography in pre-TAVR aortic annulus assessment: effects of retrospective vs. prospective ECG-synchronization on prosthesis valve selection.

To compare the diagnostic value of ultrahigh-resolution CT-angiography (UHR-CTA) compared with high-pitch spiral CTA (HPS-CTA) using a first-generation, dual-source photon-counting CT (PCD-CT) scanner for preprocedural planning of transcatheter aortic valve replacement (TAVR). Clinically referred patients with severe aortic valve stenosis underwent both, retrospective ECG-gated cardiac UHR-CTA (collimation: 120 × 0.2 mm) and prospective ECG-triggered aortoiliac HPS-CTA (collimation: 144 × 0.4 mm, full spectral capabilities) for TAVR planning from August 2022 to March 2023. Radiation dose was extracted from the CT reports, and the effective dose was calculated. Two radiologists analyzed UHR-CTA and HPS-CTA datasets, assessing the image quality of the aortic annulus, with regard to the lumen visibility and margin delineation using a 4-point visual-grading scale (ranges: 4 = "excellent" to 1 = "poor"). Aortic annulus area (AAA) measurements were taken for valve prosthesis sizing, with retrospective UHR-CTA serving as reference standard. A total of 64 patients were included (mean age, 81 years ± 7 SD; 28 women) in this retrospective study. HPS-CTA showed a lower radiation dose, 4.1 mSv vs. 12.6 mSv (p < 0.001). UHR-CTA demonstrated higher image quality to HPS-CTA (median score, 4 [IQR, 3-4] vs. 3 [IQR, 2-3]; p < 0.001). Quantitative assessments of AAA from both CTA datasets were strongly positively correlated (mean 477.4 ± 91.1 mm2 on UHR-CTA and mean 476.5 ± 90.4 mm2 on HPS-CTA, Pearson r2 = 0.857, p < 0.001) with a mean error of 22.3 ± 24.6 mm2 and resulted in identical valve prosthesis sizing in the majority of patients (91%). Patients with lower image quality on HPS-CTA (score value 1 or 2, n = 28) were more likely to receive different sizing recommendations (82%). Both UHR-CTA and HPS-CTA acquisitions using photon-counting CT technology provided reliable aortic annular assessments for TAVR planning. While UHR-CTA offers superior image quality, HPS-CTA is associated with lower radiation exposure. However, severely impaired image quality on HPS-CTA may impact on prosthesis sizing, suggesting that immediate post-scan image evaluations may require complementary UHR-CTA scanning.

Pre-Procedural Assessment of the Femoral Access Route for Transcatheter Aortic Valve Implantation: Comparison of a Non-Contrast Time-of-Flight Magnetic Resonance Angiography Protocol with Contrast-Enhanced Dual-Source Computed Tomography Angiography.

Background: We aimed to evaluate the feasibility of a non-contrast time-of-flight magnetic resonance angiography (TOF-MRA) protocol for the pre-procedural access route assessment of transcatheter aortic valve implantation (TAVI) in comparison with contrast-enhanced cardiac dual-source computed tomography angiography (CTA). Methods and Results: In total, 51 consecutive patients (mean age: 82.69 ± 5.69 years) who had undergone a pre-TAVI cardiac CTA received TOF-MRA for a pre-procedural access route assessment. The MRA image quality was rated as very good (median of 5 [IQR 4-5] on a five-point Likert scale), with only four examinations rated as non-diagnostic. The TOF-MRA systematically underestimated the minimal effective vessel diameter in comparison with CTA (for the effective vessel diameter in mm, the right common iliac artery (CIA)/external iliac artery (EIA)/common femoral artery (CFA) MRA vs. CTA was 8.04 ± 1.46 vs. 8.37 ± 1.54 (p < 0.0001) and the left CIA/EIA/CFA MRA vs. CTA was 8.07 ± 1.32 vs. 8.28 ± 1.34 (p < 0.0001)). The absolute difference between the MRA and CTA was small (for the Bland-Altman analyses in mm, the right CIA/EIA/CFA was -0.36 ± 0.77 and the left CIA/EIA/CFA was -0.25 ± 0.61). The overall correlation between the MRA and CTA measurements was very good (with a Pearson correlation coefficient of 0.87 (p < 0.0001) for the right CIA/EIA/CFA and a Pearson correlation coefficient of 0.9 (p < 0.0001) for the left CIA/EIA/CFA). The feasibility agreement between the MRA and CTA for transfemoral access was good (the right CIA/EIA/CFA agreement was 97.9% and the left CIA/EIA/CFA agreement was 95.7%, Kohen's kappa: 0.477 (p = 0.001)). Conclusions: The TOF-MRA protocol was feasible for the assessment of the access route in an all-comer pre-TAVI population. This protocol might be a reliable technique for patients at an increased risk of contrast-induced nephropathy.

Validation of color Doppler ultrasound and computed tomography in the radiologic assessment of non-malignant acute splanchnic vein thrombosis.

INTRODUCTION: International guidelines propose color Doppler ultrasound (CDUS) and contrast-enhanced computed tomography (CT) as primary imaging techniques in the diagnosis of acute splanchnic vein thrombosis. However, their reliability in this context is poorly investigated. Therefore, the aim of our study was to validate CDUS and CT in the radiologic assessment of acute splanchnic vein thrombosis, using direct transjugular spleno-portography as gold standard. MATERIALS AND METHODS: 49 patients with non-malignant acute splanchnic vein thrombosis were included in a retrospective, multicenter analysis. The thrombosis' extent in five regions of the splanchnic venous system (right and left intrahepatic portal vein, main trunk of the portal vein, splenic vein, superior mesenteric vein) and the degree of thrombosis (patent, partial thrombosis, complete thrombosis) were assessed by portography, CDUS and CT in a blinded manner. Reliability of CDUS and CT with regard to portography as gold standard was analyzed by calculating Cohen's kappa. RESULTS: Results of CDUS and CT were consistent with portography in 76.6% and 78.4% of examinations, respectively. Cohen's kappa demonstrated that CDUS and CT delivered almost equally reliable results with regard to the portographic gold standard (k = 0.634 [p < 0.001] vs. k = 0.644 [p < 0.001]). In case of findings non-consistent with portography there was no clear trend to over- or underestimation of the degree of thrombosis in both CDUS (60.0% vs. 40.0%) and CT (59.5% vs. 40.5%). CONCLUSIONS: CDUS and CT are equally reliable tools in the radiologic assessment of non-malignant acute splanchnic vein thrombosis.

Assessment of aortic annulus dimensions for transcatheter aortic valve replacement (TAVR) with high-pitch dual-source CT: Comparison of systolic high-pitch vs. multiphasic data acquisition.

OBJECTIVES: To evaluate a systolic ECG-gated high-pitch aortoiliac computed tomography (CT) angiography for planning transcatheter aortic valve implantation (TAVI). METHODS: Patients referred for TAVI underwent a combined CT imaging with retrospective, multiphasic ECG-gating of the heart and systolic ECG-gated high-pitch aortoiliac CT angiography. Consecutive patients were retrospectively included in this study group. Heart rate (HR) and heart rate variability (HRV) were assessed during the high-pitch ECG prediction phase. Aortic annulus area (AAA) was planimetrically quantified on both datasets. While only one moment of cardiac cycle was available for measurements in the high-pitch CT, the point of time in the multiphasic CT was chosen, where AAA yielded maximum size. Hypothetical prosthesis sizing was compared between multiphasic vs. high-pitch CT. RESULTS: Among 61 patients (44.2 % men, mean age: 83.3 ± 5.5 years) average heart rate and HRV were 71.0 ± 13.4 bpm and 7.3 ± 8.5 bpm. 20 patients (32.7 %) had atrial fibrillation at the time of image acquisition. There was a strong correlation of AAA as derived from multiphasic vs. the high-pitch CT (r = 0.98). The difference in AAA was 10.5 ± 17.1mm2 (455.1 ± 83.0 mm2 for multiphasic vs. 444.5 ± 87.2 mm2 for high-pitch CT) and did not reach statistical significance (p = 0.08). Hypothetical prosthesis sizing showed an agreement in 55 of 61 patients (90.2 %). A sizing based on the high-pitch CT resulted in smaller prosthesis choice in 6 patients, all of them suffering from atrial fibrillation. Mean effective radiation dose was 10.9 ± 6.1 mSv for cardiac CTA and 4.1 ± 1.0 mSv for high-pitch CTA. CONCLUSION: For patients with sinus rhythm, systolic high-pitch aortoiliac CTA provides adequate prosthesis size selection as compared with multiphasic ECG-gated cardiac CTA and may result in significantly reduced radiation exposition.

Pre-procedural assessment of aortic annulus dimensions for transcatheter aortic valve replacement: comparison of a non-contrast 3D MRA protocol with contrast-enhanced cardiac dual-source CT angiography.

AIMS: To evaluate the feasibility of a non-contrast three-dimensional (3D)-FLASH magnetic resonance angiography (MRA) protocol for pre-procedural aortic annulus assessment for transcatheter aortic valve replacement (TAVR) in comparison with cardiac dual-source computed tomography angiography (CTA). METHODS AND RESULTS: In this prospective study, 69 of 104 consecutive patients (mean age 81.8 ± 5.4 years, 37.7% arrhythmic) with severe aortic stenosis who had undergone pre-TAVR cardiac CTA received a respiratory and ECG-triggered, non-contrast 3D-FLASH MRA at 3 T. Annular area measurements were obtained at mid-diastole for both modalities whereas maximum systolic area was assessed by CTA only. Systolic MRA dimensions were modelled, by adding the relative difference of systolic and diastolic CTA area dimensions as a corrective factor. Hypothetical prosthesis sizing was performed based on systolic CTA, diastolic, and modelled systolic MRA area measurements. MR image quality and degree of annular calcifications were evaluated using 4-point-grading scales. The mean acquisition time was 14 ± 4.2 min. The mean image quality was 3.1 ± 0.9 with only two examinations rated non-diagnostic. The mean degree of calcifications was equal. As assessed by Bland-Altman analysis, there was no relevant systematic difference between area measurements for modelled systolic MRA and systolic CTA [the mean difference -3.1 mm(2) (limits of agreement -44.4 mm(2); 38.2 mm(2))]. Agreement for hypothetical prosthesis sizing was found in 63 of 67 (94%) patients for systolic CTA and modelled systolic MRA. CONCLUSION: The employed non-contrast 3D-FLASH MRA protocol allows for reliable assessment of aortic annulus dimensions and calcifications even in the presence of arrhythmias in an all-comers pre-TAVR population. Implementation of this technique appears legitimate in patients at an increased risk for contrast-induced nephropathy.