RT Journal Article SR Electronic T1 Lung ventilation/perfusion scintigraphy for the screening of chronic thromboembolic pulmonary hypertension (CTEPH): which criteria to use? JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 3352 OP 3352 VO 63 IS supplement 2 A1 Romain Le Pennec A1 Cécile Tromeur A1 Charles Orione A1 Philippe Robin A1 Raphaël Le Mao A1 Claire De Moreuil A1 Mitja Jevnikar A1 Clément Hoffman A1 Laurent Savale A1 Francis Couturaud A1 Olivier Sitbon A1 David Montani A1 Xavier Jaïs A1 Gregoire Le Gal A1 Pierre-Yves Salaün A1 Marc Humbert A1 Pierre-Yves Le Roux YR 2022 UL http://jnm.snmjournals.org/content/63/supplement_2/3352.abstract AB 3352 Introduction: The diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH) is a major challenge as it is a curable cause of pulmonary hypertension (PH). Ventilation/Perfusion (V/Q) lung scintigraphy is the imaging modality of choice for the screening of CTEPH. However, there is no consensus on the criteria to use for interpretation. The aim of this study was to assess the accuracy of various interpretation criteria of planar V/Q scintigraphy for the screening of CTEPH in patients with PH.Methods: The eligible study population consisted of consecutive patients with newly diagnosed PH in the Brest University Hospital, France. Final diagnosis (CTEPH or non-CTEPH) was established in a referential center on the management of PH, based on the ESC/ERS guidelines and a minimum follow-up of 3 years. A retrospective central review of planar V/Q scintigraphy was performed by three nuclear physicians blinded to clinical findings and to final diagnosis. The number, extent (sub segmental or segmental) and type (matched or mismatched) of perfusion defects were reported. Sensitivity and specificity were evaluated for various criteria based on the number of mismatched perfusion defects and the number of perfusion defects (regardless of ventilation). Receiver operating characteristic (ROC) curves were generated and areas under the curve (AUC) were calculated for both.Results: A total of 226 patients with newly diagnosed PH were analyzed. 56 (24.8%) were diagnosed with CTEPH while 170 patients (75.2%) were diagnosed with non-CTEPH. The optimal threshold was 2.5 segmental mismatched perfusion defects, providing a sensitivity of 100 % (95% CI 93.6-100%) and a specificity of 94.7% (95%CI 90.3-97.2%). Lower diagnostic cut-offs of mismatched perfusion defects provided similar sensitivity but lower specificity. Ninety five percent of patients with CTEPH had more than 4 segmental mismatched defects. An interpretation only based on perfusion provided similar sensitivity but a specificity of 81.8% (95%CI 75.3-86.9%).Conclusions: Our study confirmed the high diagnostic performance of planar V/Q scintigraphy for the screening of CTEPH in patients with PH. The optimal diagnostic cut-off for interpretation was 2.5 segmental mismatched perfusion defects. An interpretation only based on perfusion defects provided similar sensitivity but lower specificity.