Software-Based Hybrid Perfusion SPECT/CT Provides Diagnostic Accuracy When Other Pulmonary Embolism Imaging Is Indeterminate

Abstract

Purpose To investigate the diagnostic performance of perfusion single-photon emission computed tomography/computed tomography (Q-SPECT/CT) in patients suspected to have pulmonary embolism (PE) but with indeterminate computed tomographic pulmonary angiography (CTPA) or planar ventilation/perfusion (V/Q) scans. Methods This retrospective study included two groups of patients. Group I consisted of 49 patients with nondiagnostic CTPA. These 49 patients underwent subsequent V/Q scans. Further Q-SPECTs were obtained in patients with indeterminate planar images and fused with existing CTPA. Group II consisted of 182 non-CTPA patients with indeterminate V/Q scans. These 182 patients underwent further Q-SPECT and separate noncontrast low-dose CT chest. Fusion Q-SPECT/ CT scans were obtained through FDA-approved software and interpreted according to published criteria as positive, negative, or indeterminate for PE. Upon retrospective analyses, the final diagnosis was made using composite reference standards including all available clinical and imaging information for at least 6-month follow-up. ResultsIn group I patients, 1 was positive, 24 were negative, and another 24 (49 %, 24/49) were indeterminate. In the subsequent 24 Q-SPECT/CTPAs, 4 were positive, 19 were negative, and 1 was indeterminate (4.2 %, 1/24). In group II patients, 9 (4.9 %, 9/182) were indeterminate, 33 were positive, and 140 were negative. The combined nondiagnostic rate for Q-SPECT/CT was only 4.9 % (10/ 206). There was six false-negative and one false-positive Q-SPECT/CT examinations. The sensitivity, specificity, and positive and negative predictive value of Q-SPECT/ CT were 85.7 % (36/42), 99.4 % (153/154), 97.3 % (36/ 37) and 96.2 % (153/159), respectively. Conclusions Q-SPECT/CT improves the diagnostic rate with promising accuracy in diagnosing PE that yields a satisfactory clinical verdict, especially when the CTPA and planar V/Q scan are indeterminate.

Quantitative single-photon emission computed tomography/computed tomography for technetium pertechnetate thyroid uptake measurement

“…The clinical application of quantitative SPECT/CT is long overdue since the suggested potential usefulness has been repeatedly stated in the literature. [ 1 , 2 , 22 , 23 ] In the present study, the quantitative SPECT/CT proved to be more accurate than the previous gold standard test for thyroid uptake measurement. The low performance of the TUS for the 99m TcO 4 %thyroid uptake measurement has been previously acknowledged in the societies of endocrinology and nuclear medicine (personal communication).…”

2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS)

“…Several studies suggest that data acquisition in single-photon emission CT (SPECT) imaging, with or without low-dose CT, may decrease the proportion of non-diagnostic scans to as low as 0-5% [121,[126][127][128]. However, most studies reporting on the accuracy of SPECT are limited by their retrospective design [129,130] or the inclusion of SPECT itself in the reference standard [127], and only one study used a validated diagnostic algorithm [131]. The diagnostic criteria for SPECT also varied; most studies defined PE as one CTPA: computed tomographic pulmonary angiography; mGy: milligray; mSv: millisieverts; PE: pulmonary embolism; SPECT: single-photon emission computed tomography; V/Q: ventilation/perfusion (lung scintigraphy).…”

Ventilation/perfusion SPECT for the diagnosis of pulmonary embolism: A systematic review

“…As per study protocol, nine studies were excluded because they assessed the performance of perfusion SPECT/CT imaging, without ventilation SPECT. [17][18][19][20][21][22][23][24][25] Computed based on provided data. In the study from Le Duc Pennec et al, results were provided according to the 4 categories of the PIOPED classification.…”