Prosthetic heart valve assessment with multidetector-row CT: imaging characteristics of 91 valves in 83 patients

Multidetector CT (MDCT) has shown potential for prosthetic heart valve (PHV) assessment. We assessed the image quality of different PHV types to determine which valves are suitable for MDCT evaluation. All ECG-gated CTs performed in our institutions since 2003 were reviewed for the presence of PHVs. After reconstruction in 3 specific PHV planes, image quality of the supravalvular, perivalvular, subvalvular and valvular regions was scored on a four-point scale (1 = non-diagnostic, 2 = moderate, 3 = good and 4 = excellent) by two independent observers. Eighty-four CT examinations (66 cardiac, 18 limited-dose aortic protocols) of 83 patients with a total of 91 PHVs in the aortic (n = 71), mitral (n = 17), pulmonary (n = 1) and tricuspid (n = 2) position were included. CT was performed on a 16-slice (n = 4), 64-slice (n = 28) or 256-slice (n = 52) MDCT system. Median image quality scores for the supra-, peri- and subvalvular regions and valvular detail were (3.5, 3.3, 3.5 and 3.5, respectively) for bileaflet PHV; (3.0, 3.0, 3.5 and 3.0, respectively) for Medtronic Hall PHV; (1.0, 1.0, 1.0 and 1.0, respectively) for Björk-Shiley and Sorin monoleaflet PHV and (3.5, 3.5, 4.0 and 2.0 respectively) for biological PHV. Currently implanted PHVs have good image quality on MDCT and are suitable for MDCT evaluatio

Prospective ECG triggering reduces prosthetic heart valve-induced artefacts compared with retrospective ECG gating on 256-slice CT

Item does not contain fulltextOBJECTIVES: Multidetector computed tomography (MDCT) has diagnostic value for the evaluation of prosthetic heart valve (PHV) dysfunction but it is hampered by artefacts. We hypothesised that image acquisition using prospective triggering instead of retrospective gating would reduce artefacts related to pulsating PHV. METHODS: In a pulsatile in vitro model, a mono- and bileaflet PHV were imaged using 256 MDCT at 60, 75 and 90 beats per minute (BPM) with either retrospective gating (120 kV, 600 mAs, pitch 0.2, CTDI(vol) 39.8 mGy) or prospective triggering (120 kV, 200 mAs, CTDI(vol) 13.3 mGy). Two thresholds (>175 and <-45HU), derived from the density of surrounding structures, were used for quantification of hyper- and hypodense artefacts. Image noise and artefacts were compared between protocols. RESULTS: Prospective triggering reduced hyperdense artefacts for both valves at every BPM (P = 0.001 all comparisons). Hypodense artefacts were reduced for the monoleaflet valve at 60 (P = 0.009), 75 (P = 0.016) and 90 BPM (P = 0.001), and for the bileaflet valves at 60 (P = 0.001), 90 (P = 0.001) but not at 75 BPM (P = 0.6). Prospective triggering reduced image noise at 60 (P = 0.001) and 75 (P < 0.03) but not at 90 BPM. CONCLUSIONS: Compared with retrospective gating, prospective triggering reduced most artefacts related to pulsating PHV in vitro. KEY POINTS: * Computed tomographic images are often degraded by prosthetic heart valve-induced artefacts * Prospective triggering reduces prosthetic heart valve-induced artefacts in vitro * Artefact reduction at 90 beats per minute occurs without image noise reduction * Prospective triggering may improve CT image quality of moving hyperdense structures.1 juni 201

Multidetector CT imaging of mechanical prosthetic heart valves: quantification of artifacts with a pulsatile in-vitro model

Item does not contain fulltextOBJECTIVES: Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design. METHODS: A Medtronic Hall tilting disc (MH), and Carbomedics (CM), St Jude (SJM), and ON-X bileaflet valves underwent CT in an in-vitro model using retrospective gating with a 64 detector CT system in stationary and pulsatile conditions. Artifacts and radiopaque component volumes were quantified with thresholds based on surrounding structures and valvular components. RESULTS: Hypodense artifacts volumes (mm(3)) were 1,029 +/- 147, 535 +/- 53, 371 +/- 16, and 366 +/- 18 for the SJM, MH, CM and ON-X valves (p < 0.001 except for the latter two valves p = 0.43). Hyperdense artifact volumes were 3,546 +/- 141, 2,387 +/- 103, 2,003 +/- 102, and 3,033 +/- 31 for the SJM, MH, CM and ON-X valve, respectively (all differences p < 0.001). Leaflet motion affected hypodense (F = 41.5, p < 0.001) and hyperdense artifacts (F = 53.7, p < 0.001). Closed and moving leaflets were associated with the least and the most artifacts respectively (p < 0.001, both artifact types). CONCLUSION: Both valve design and leaflet motion affect PHV-induced artifacts. Best imaging results may be expected for the CM valve during phases in which the leaflets are closed

Coronary artery assessment by multidetector computed tomography in patients with prosthetic heart valves

Objectives Patients with prosthetic heart valves may require assessment for coronary artery disease. We assessed whether valve artefacts hamper coronary artery assessment by multidetector CT. Methods ECG-gated or -triggered CT angiograms were selected from our PACS archive based on the presence of prosthetic heart valves. The best systolic and diastolic axial reconstructions were selected for coronary assessment. Each present coronary segment was scored for the presence of valve-related artefacts prohibiting coronary artery assessment. Scoring was performed in consensus by two observers. Results Eighty-two CT angiograms were performed on a 64-slice ( = 27) or 256-slice ( = 55) multidetector CT. Eighty-nine valves and five annuloplasty rings were present. Forty-three out of 1160 (3.7%) present coronary artery segments were non-diagnostic due to valve artefacts (14/82 patients). Valve artefacts were located in right coronary artery (15/43; 35%), left anterior descending artery (2/43; 5%), circumflex artery (14/43; 32%) and marginal obtuse (12/43; 28%) segments. All cobalt-chrome containing valves caused artefacts prohibiting coronary assessment. Biological and titanium-containing valves did not cause artefacts except for three specific valve types. Conclusions Most commonly implanted prosthetic heart valves do not hamper coronary assessment on multidetector CT. Cobalt-chrome containing prosthetic heart valves preclude complete coronary artery assessment because of severe valve artefacts. Key Points Most commonly implanted prosthetic heart valves do not hamper coronary artery assessment Prosthetic heart valve composition determines the occurrence of prosthetic heart valve-related artefacts Bjork-Shiley and Sorin tilting disc valves preclude diagnostic coronary artery segment assessmen

Baseline MDCT findings after prosthetic heart valve implantation provide important complementary information to echocardiography for follow-up purposes

Objectives: Recent studies have proposed additional multidetector-row CT (MDCT) for prosthetic heart valve (PHV) dysfunction. References to discriminate physiological from pathological conditions early after implantation are lacking. We present baseline MDCT findings of PHVs 6 weeks post implantation. Methods: Patients were prospectively enrolled and TTE was performed according to clinical guidelines. 256-MDCT images were systematically assessed for leaflet excursions, image quality, valve-related artefacts, and pathological and additional findings. Results: Forty-six patients were included comprising 33 mechanical and 16 biological PHVs. Overall, MDCT image quality was good and relevant regions remained reliably assessable despite mild-moderate PHV-artefacts. MDCT detected three unexpected valve-related pathology cases: (1) prominent subprosthetic tissue, (2) pseudoaneurysm and (3) extensive pseudoaneurysms and valve dehiscence. The latter patient required valve surgery to be redone. TTE only showed trace periprosthetic regurgitation, and no abnormalities in the other cases. Additional findings were: tilted aortic PHV position (n = 3), pericardial haematoma (n = 3) and pericardial effusion (n = 3). Periaortic induration was present in 33/40 (83 %) aortic valve patients. Conclusions: MDCT allowed evaluation of relevant PHV regions in all valves, revealed baseline postsurgical findings and, despite normal TTE findings, detected three cases of unexpected, clinically relevant pathology. Key Points: • Postoperative MDCT presents baseline morphology relevant for prosthetic valve follow-up. • 83 % of patients show periaortic induration 6 weeks after aortic valve replacement. • MDCT detected three cases of clinically relevant pathology not found with TTE. • Valve dehiscence detection by MDCT required redo valve surgery in one patient. • MDCT is a suitable and complementary imaging tool for follow-up purposes

Surgically implanted aortic valve bioprostheses deform after implantation: insights from computed tomography

Objective: Little is known about the prevalence and degree of deformation of surgically implanted aortic biological valve prostheses (bio-sAVRs). We assessed bio-sAVR deformation using multidetector-row computed tomography (MDCT). Methods: Three imaging databases were searched for patients with MDCT performed after bio-sAVR implantation. Minimal and maximal valve ring diameters were obtained in systole and/or diastole, depending on the acquired cardiac phase(s). The eccentricity index (EI) was calculated as a measure of deformation as (1 − (minimal diameter/maximal diameter)) × 100%. EI of 10% non-circular. Indications for MDCT and implanted valve type were retrieved. Results: One hundred fifty-two scans of bio-sAVRs were included. One hundred seventeen measurements were performed in systole and 35 in diastole. None or trivial deformation (EI 5%) in 56% of studied cases and were considered non-circular (eccentricity index > 10%) in 17% of studied valves. • The higher deformity rate found in bio-sAVRs with (suspected) valve pathology could suggest that geometric deformity may play a role in leaflet malformation and thrombus formation similar to that of transcatheter heart valves