(2023) van der Bie | PCCT for TAVR planning and follow-up

Daniel Stromer

This early case series illustrates how UHR PCCT can improve structural heart imaging before and after TAVR, particularly through sharper depiction of the aortic valve, annulus, coronary arteries, prosthetic valve frames, and vascular access routes. UHR acquisition allows 0.2-mm sections, compared with 0.4 mm in the regular PCCT mode, helping reduce calcium and metal blooming.

In pre-TAVR imaging, sharper reconstruction improved visualization of heavily calcified coronary arteries and IMAR substantially improved femoral-artery assessment despite bilateral hip prostheses. Post-TAVR, PCCT depicted hypoattenuating leaflet thickening, valve-in-valve anatomy, and an incompletely expanded left-main stent with an assessable lumen despite substantial surrounding metal and calcium.

The spectral capabilities add information beyond spatial resolution: VMI, virtual noncontrast, and iodine maps helped characterize leaflet abnormalities and distinguish iodine from calcification. These are promising proof-of-concept applications, but the report is a small case series rather than a comparative diagnostic-accuracy study.

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Figure 2: Photon-counting detector CT scan for pre–transcatheter aortic valve replacement planning in an 81-year-old female patient (with contrast material). (A) Electrocardiogram shows a highly irregular heart rate was present at the time of scanning. (B) Contrast-enhanced visualization of the aortic annulus and native aortic valve in the sagittal plane with sharp delineation of the leaflets and a small calcification in the nodule of Arantius (white arrow). (C) Ultra-high-resolution image shows the coronary arteries (Bv56 kernel, multiplanar reformatted image). (D) Conventional reconstructions at 0.6-mm section thickness (Bv40 kernel) for comparison (multiplanar reformatted image). (E, F) Axial reconstructions at the level of the femoral arteries (arrows) without (E) and with (F) iterative metal artifact reduction (IMAR) reconstruction. QIR = quantitative iterative reconstruction.

Protocol

Detail	Value
Scanner	NAEOTOM Alpha, dual-source PCCT
Regular detector configuration	144 × 0.4 mm
UHR detector configuration	120 × 0.2 mm
UHR section thickness	0.2 mm
Pre-TAVR cardiac acquisition, Case 2	Prospectively ECG-triggered UHR CTA, 15–53% RR
Tube voltage, Case 2 [kVp]	120
IQ level, Case 2	43
CTDIvol, Case 2 cardiac [mGy]	26.8
Access-route acquisition, Case 2	High-pitch skull base to groin, 0.4-mm sections
Access-route IQ level	41
Access-route CTDIvol [mGy]	2.45
Coronary UHR kernel, Case 2	Bv56
Comparator reconstruction, Case 2	Bv40, 0.6-mm sections
Metal artifact reduction	IMAR for vascular access assessment
Post-TAVR acquisition, Case 3	120 kV; IQ 50; CTDIvol 15.2 mGy
Spectral post-processing, Case 3	VMI, virtual noncontrast, iodine map, fused iodine/VNC
Post-TAVR acquisition, Case 4	Retrospective ECG-gated UHR; 120 kV; IQ 60; CTDIvol 58 mGy
Valve-in-valve acquisition, Case 5	Full-cycle retrospective ECG-gated UHR; 120 kV; IQ 65; CTDIvol 61.5 mGy
Valve-in-valve reconstruction	Bv56; QIR 4
Ex vivo valve acquisition	UHR, 140 kV
Ex vivo reconstruction	Qr89/Qr76; QIR 4

Key Results

Parameter	Main finding
Spatial resolution	UHR PCCT enabled 0.2-mm sections vs 0.4 mm in regular PCCT mode
Pre-TAVR coronary imaging	Bv56 UHR reconstruction reduced calcium blooming compared with 0.6-mm Bv40
Access-route assessment	IMAR improved femoral-artery visualization despite bilateral hip prostheses
Leaflet assessment	PCCT demonstrated hypoattenuating leaflet thickening after TAVR and valve-in-valve TAVR
Coronary stent assessment	Left-main stent lumen remained assessable; incomplete expansion from adjacent calcification was visualized
Spectral imaging	VMI, VNC, and iodine maps provided additional characterization of valve leaflets and calcification

Source:
van der Bie J, Sharma SP, van Straten M, Bos D, Hirsch A, Dijkshoorn ML, Adrichem R, van Mieghem NMDA, Budde RPJ. Photon-counting Detector CT in Patients Pre- and Post-Transcatheter Aortic Valve Replacement. Radiology: Cardiothoracic Imaging. 2023;5(2). doi:10.1148/ryct.220318.