The case report hase been published by:
Tateishi, R, Nishimura, T, Tao, S. et al. Photon-Counting Detector Computed Tomography Depicts a Ventricular Tachycardia Substrate: Periaortic Septal Intramural Late Iodine Enhancement. J Am Coll Cardiol Case Rep. 2026 Apr, 31 (15) . https://doi.org/10.1016/j.jaccas.2026.107250
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Visual Summary Spatial Relationship Between LIE on PCD-CT and Arrhythmogenic Substrate(A) Preprocedural photon-counting detector computed tomography image and three-dimensional visualization using ADAS 3D software. The red arrow indicates late iodine enhancement. (B) Isochronal late activation map. Lines of conduction block with split potentials (yellow arrows) were observed in the RVOT and periaortic septal region of the LVOT, spatially corresponding to the edge of the late iodine enhancement area. Ao = aorta; LIE = late iodine enhancement; LV = left ventricle; LVOT = left ventricular outflow tract; RV = right ventricle; RVOT = right ventricular outflow tract; PA = pulmonary artery; PCD-CT = photon-counting detector computed tomography.
Background
Recent studies have demonstrated that delayed enhancement using contrast-enhanced computed tomography corresponds with late gadolinium enhancement on cardiac magnetic resonance imaging. However, few studies have evaluated scar-related ventricular tachycardia (VT) substrates using high-resolution photon-counting detector computed tomography (PCCT).
Case Summary
A 49-year-old man with cardiac sarcoidosis underwent catheter ablation of monomorphic VT. Preoperative iodine mapping on PCD-CT showed late iodine enhancement (LIE) localized to the septal region between the periaortic region and right ventricular outflow tract. Electroanatomic mapping revealed a localized abnormal voltage area and line of conduction block with split potentials colocalized with the LIE. Radiofrequency ablation was performed from both the right and left ventricular outflow tracts and successfully eliminated the VT inducibility. No ICD shocks have occurred after the procedure.
Discussion
PCD-CT provides improved signal detection and superior spatial resolution, enabling visualization of VT substrates in anatomically challenging regions. In patients who are contraindicated for cardiac magnetic resonance imaging, PCD-CT serves as a valuable alternative imaging modality.
Take-Home Messages
The higher spatial resolution of PCD-CT enables a more precise detection of periaortic substrates, whereas detecting late gadolinium enhancement on cardiac magnetic resonance imaging is challenging given a thin myocardium and anatomical complexity.•Because PCD-CT does not have the same restrictions as cardiac magnetic resonance imaging, it can be used in patients with non–MRI-conditional implantable cardioverter-defibrillators to accurately identify and locate ventricular tachycardia substrates.
