Dual-energy CT perfusion and angiography in chronic thromboembolic pulmonary hypertension: diagnostic accuracy and concordance with radionuclide scintigraphy.

OBJECTIVES: To evaluate the diagnostic accuracy of dual-energy computed tomography (DECT) perfusion and angiography versus ventilation/perfusion (V/Q) scintigraphy in chronic thromboembolic pulmonary hypertension (CTEPH), and to assess the per-segment concordance rate of DECT and scintigraphy. METHODS: Forty consecutive patients with proven pulmonary hypertension underwent V/Q scintigraphy and DECT perfusion and angiography. Each imaging technique was assessed for the location of segmental defects. Diagnosis of CTEPH was established when at least one segmental perfusion defect was detected by scintigraphy. Diagnostic accuracy of DECT perfusion and angiography was assessed and compared with scintigraphy. In CTEPH patients, the per-segment concordance between scintigraphy and DECT perfusion/angiography was calculated. RESULTS: Fourteen patients were diagnosed with CTEPH and 26 with other aetiologies. DECT perfusion and angiography correctly identified all CTEPH patients with sensitivity/specificity values of 1/0.92 and 1/0.93, respectively. At a segmental level, DECT perfusion showed moderate agreement (κ = 0.44) with scintigraphy. Agreement between CT angiography and scintigraphy ranged from fair (κ = 0.31) to slight (κ = 0.09) depending on whether completely or partially occlusive patterns were considered, respectively. CONCLUSIONS: Both DECT perfusion and angiography show satisfactory performance for the diagnosis of CTEPH. DECT perfusion is more accurate than angiography at identifying the segmental location of abnormalities. KEY POINTS: • Chronic thromboembolic pulmonary hypertension (CTEPH) is potentially treatable by surgery. • Dual-energy computed tomography (DECT) allows angiography and perfusion using a single acquisition. • Both DECT perfusion and angiography showed satisfactory diagnostic performance in CTEPH. • DECT perfusion was more accurate than angiography in identifying segmental abnormalities.

Absolute quantification of left ventricular global and regional function at nuclear MPI using ultrafast CZT SPECT: initial validation versus cardiac MR.

UNLABELLED: We sought to evaluate the accuracy of myocardial perfusion imaging (MPI) using cadmium-zinc-telluride (CZT) SPECT cameras for the measurement of left ventricular (LV) global and regional function, and the performance of absolute wall motion (WM) and wall thickness (WT) measurements for the detection of myocardial scarring, using cardiac MR as a reference. METHODS: Sixty patients with known or suspected coronary artery disease underwent MPI using a CZT SPECT camera, as well as cine and delayed enhanced cardiac MR. Gated MPI data were processed using quantitative gated SPECT software. LV global function was assessed by measuring LV end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF). Regional function was assessed by quantifying segmental WM and WT according to the 17-segment model. Myocardial scarring was quantified on each segment using delayed enhanced cardiac MR. Agreement between SPECT and cardiac MR was assessed using Pearson correlation and Bland-Altman analyses. The influence of measurement magnitude on the agreement was analyzed using Spearman correlation coefficients between the mean and SD of measurements. The performance of WM and WT for the detection of segments with more than 25% scar transmurality was assessed using receiver-operating-characteristic analysis. RESULTS: Correlation between methods was excellent for EF (R = 0.81, P < 0.0001) and ESV (R = 0.88, P < 0.0001) and was good for EDV (R = 0.71, P < 0.0001). Agreement was good for EF (bias, -2.7%; limits of agreement, -15.5 to +10.1) but was lower for EDV (bias, -29.7 mL; limits of agreement, -68.3 to +8.9) and ESV (bias, -9.9 mL; limits of agreement, -30.7 to +10.9). Correlation between methods was fair for WM (R = 0.49, P < 0.0001) and WT (R = 0.48, P < 0.0001). SPECT underestimated WT (bias, -41%; limits of agreement, -108 to +26), with an error depending on thickening magnitude (ρ = 0.70, P < 0.0001). The agreement in WM measurement was higher (bias, -1.4 mm; limits of agreement, -6.9 to +4) and independent of motion magnitude (ρ = 0.006, P = 0.86). WM and WT were equally able to identify scarred segments (area under the receiver-operating-characteristic curve, 0.74 ± 0.03 and 0.74 ± 0.03, respectively). CONCLUSION: MPI using CZT SPECT cameras and quantitative gated SPECT analysis accurately quantifies EF but still underestimates LV volumes. WM shows a higher agreement with cardiac MR than does WT, with errors in WT measurement increasing at greater thicknesses. Absolute quantification of segmental WM and WT can equally be used to identify myocardial scarring.