The Utility of Hybrid SPECT/CT Lung Perfusion Scintigraphy in Pulmonary Embolism Diagnosis

Abstract

Background: Pulmonary embolism (PE) is diagnosed either by ventilation/perfusion (V/Q) scintigraphy or pulmonary CT angiography. One of the imaging methods used in nuclear medicine is hybrid SPECT/CT scintigraphy. Objectives: The aim of this study was to evaluate the utility of SPECT/CT(Q) scintigraphy in the diagnosis of PE and to compare SPECT/CT(Q) with planar(Q) and SPECT(Q) methods. Methods: The study group consisted of 109 consecutive patients suspected of having PE referred for performing lung scintigraphy. The inclusion criteria were: performance of perfusion planar, SPECT and SPECT/CT scans; availability of clinical data covering a 6-month follow-up period, and D-dimer level testing. The number of eligible patients was 84. PE was reported in patients with at least 1 segmental or 2 subsegmental perfusion defects without parenchymal abnormalities on CT scans. PE was excluded when there was a normal perfusion pattern or perfusion defects were caused by lung parenchymal abnormalities or were not arranged in accordance with the pulmonary vasculature. Results: Twenty-six patients (31%) had a final diagnosis of PE. The sensitivity and specificity values of each method were as follows: planar(Q) 73 and 43%, SPECT(Q) 88 and 47% and SPECT/CT(Q) 100 and 83%. SPECT/CT(Q) yielded a significantly higher diagnostic accuracy than planar(Q) (p < 0.001) and SPECT(Q) (p < 0.001) scans. Conclusions: We conclude that hybrid SPECT/CT(Q) imaging has a high diagnostic efficacy in the diagnosis of PE. Lung perfusion scintigraphy performed with a hybrid SPECT/CT device has a significantly higher sensitivity and specificity than scanning performed with the planar or SPECT technique.

Clinical utility of perfusion (Q)-single-photon emission computed tomography (SPECT)/CT for diagnosing pulmonary embolus (PE) in COVID-19 patients with a moderate to high pre-test probability of PE

“…Cobes et al retrospectively analyzed V/Q SPECT/CTs in 5 patients hospitalized with COVID-19 and determined that V/Q SPECT/CT could play a role diagnosing embolic complications while following meticulous hygiene [ 22 ]. However, combining a low-dose chest CT with Q-only SPECT can also satisfactorily demonstrate etiologies of potential non-embolic false positive results, such as pulmonary emphysema or bullous disease [ 23 ]. Ventilation studies can contaminate staff members and equipment and in a high-volume nuclear medicine institution, the necessary decontamination steps may not be offset by the benefit of ventilation imaging in some patients during the COVID-19 pandemic.…”

“…The authors reported a similar sensitivity and specificity to Lu et al (100 and 83%, respectively) concluding that Q-SPECT/CT imaging had a high diagnostic efficacy in evaluating patients suspected to have PE. In addition, the inclusion of a chest CT (even at low dose) adds value by characterizing acute pulmonary pathology which could account for the patient’s clinical presentation [ 23 ]. In addition, based on the current European Association of Nuclear Medicine guidelines, Q-only SPECT is already recommended as standard of care, for example in pregnant patients with suspected PE [ 8 ].…”

A review of imaging modalities in pulmonary hypertension

“…In a study of 84 patients, SPECT/CT yielded a significantly higher diagnostic accuracy for PE (sensitivity 100% and specificity 83%) than planar and SPECT scans. [77] More recently, SPECT/CT has been used to evaluate CTEPH. [78] A study of 15 patients with precapillary PH and 11 healthy controls calculated a perfusion redistribution index (PRI) using SPECT/CT images.…”

Pulmonary thromboembolism: new diagnostic imaging techniques

“…There have been few studies on the utility of SPECT/CT in the diagnosis of PTE, and there are no definitive recommendations regarding the method. However, it is believed that SPECT/CT has a high (99%) accuracy for the diagnosis, with a sensitivity of 97-100% and a specificity of 83-100% ( 19 , 20 ) .…”