The purpose of this article is to outline recent progress made in ventilation-perfusion (V/Q) scintigraphy imaging techniques and the interpretation systems used for the diagnosis of pulmonary ...embolism (PE). Various state-of-the-art approaches that can be selected according to the needs dictated by the medical practice environment and specific patient groups are presented.
Although advances in tomographic imaging have certainly improved the sensitivity of V/Q scans for the diagnosis of PE, they may lead to overdiagnosis by revealing small and clinically insignificant PEs.
Sickle cell disease, a complex disorder with known pulmonary complications, has the potential to confound the diagnosis of pulmonary embolism. We hypothesized that when the choice of imaging is ...guided by chest radiographic results, CT pulmonary angiography (CTPA) and ventilation-perfusion (V/Q) scintigraphy have comparable diagnostic performance in sickle cell disease.
A retrospective cohort of adults with sickle cell disease who were imaged for suspected pulmonary embolism with either CTPA or V/Q, from 2000 to 2016 at our institution, was established. To reduce radiation exposure, our practice recommends V/Q for stable patients with normal chest radiographs. Results of index pulmonary embolism imaging, 90-d follow-up, and results of chest radiography were recorded.
Two hundred forty-five adults with sickle cell disease comprised the cohort. The mean age (±SD) was 33 ± 10.5 y, and 58% (141) were men. Index imaging was V/Q in 62.9% (
= 154) and CTPA in 37.1% (
= 91). Chest radiographs, performed in 96.3% (
= 236), were normal in 72.9% (
= 172). Imaging results for pulmonary embolism were negative in 88.2% (
= 216), positive in 4.1% (
= 10), and indeterminate in 7.8% (
= 19) with no difference between V/Q and CTPA (
= 0.63). Reimaging within 90 d occurred in 9.8% (
= 24), 14.7% (20/136) after initial V/Q, and 5% (4/109) after initial CTPA (
= 0.08). Reimaging revealed a pulmonary embolism diagnosis after negative/indeterminate results in 0.7% (1/149) of V/Qs and 1.2% of (1/86) CTPAs (
= 0.69). Over the 17-y study period, 47% (114/245) underwent repeated imaging, and 11% (27/245) were diagnosed with pulmonary embolism at least once.
In sickle cell disease patients with suspected pulmonary embolism, positive imaging rates were low for any given clinical presentation, but 11% of the cohort was diagnosed with pulmonary embolism over the 17-y study period. CTPA and V/Q performed comparably for pulmonary embolism diagnosis when the choice of imaging was guided by results of chest radiography. Hence, V/Q is a reasonable first choice for sickle cell disease patients with normal chest radiographs.
The purpose of this study was to evaluate a pulmonary embolism (PE) perfusion-only screening (POS) protocol introduced during the coronavirus disease 2019 (COVID-19) pandemic surge. Subjects without ...dense parenchymal lung opacities were studied; those with less than 1 segmental perfusion defect were considered to have no PE, whereas those exhibiting 1 or more defects were indeterminate, mandating additional examinations to determine the final diagnosis.
We analyzed demographic information, clinical data, imaging findings, and follow-up data from the electronic records of COVID-19 patients who underwent lung scintigraphy during the 60-d study period.
In total, 53 studies were performed on 17 COVID-19-positive and 36 COVID-19-negative patients. The POS protocol efficiently excluded PE in 79% of cases; the remaining 21%, indeterminate for PE, were generally referred for alternative testing or were directly anticoagulated. In patients with negative POS results, there was a very low mortality before hospital discharge (1/42) and normal results on follow-up studies (6/6).
The POS protocol, implemented during the COVID-19 surge, efficiently and safely excluded PE in 79% of patients.
Asthma and pulmonary embolism (PE) can present with overlapping symptoms, and distinguishing between these 2 conditions can be challenging. Asthma may limit imaging for PE because of either worsened ...ventilation defects on ventilation-perfusion scanning (VQ) or increased motion artifacts on CT pulmonary angiography (CTPA).
We identified adults evaluated for PE with VQ or CTPA from 2012 to 2016. Patients with chronic lung disease (other than asthma) were excluded. Studies were classified as negative, positive, or nondiagnostic. Follow-up of negative cases was reviewed to determine the rate of repeat exams (within 1 wk) and the false-negative rate (defined as diagnosis of venous thromboembolism within 90 d).
We reviewed 19,412 adults (aged 52 ± 18 y, 70% women) evaluated for PE (60% with VQ, 40% with CTPA); 23% had a history of asthma. Nondiagnostic results were comparable for those with and without asthma for both VQ (asthma, 3.3%; nonasthma, 3.8%;
= 0.223) and CTPA (asthma, 1.6%; nonasthma, 1.5%;
= 0.891). A history of asthma was not associated with a higher rate of repeat exams after negative imaging for VQ (asthma, 1.9%; nonasthma, 2.1%;
= 0.547) or CTPA (asthma, 0.6%; nonasthma, 0.6%;
= 0.796), nor was a history of asthma associated with a higher false-negative rate for VQ (asthma, 0.4%; nonasthma, 0.9%;
= 0.015) or CTPA (asthma, 1.9%; nonasthma 1.5%;
= 0.347).
A history of asthma in the preceding 10 y was not associated with impaired diagnostic performance of PE imaging for either VQ or CTPA.
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