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. Methods: 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. Results: 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). Conclusion: The POS protocol, implemented during the COVID-19 surge, efficiently and safely excluded PE in 79% of patients.

Hepatocellular carcinoma (HCC) is the most common type of liver cancer, with a poor median survival when left untreated. Extrahepatic metastases involving musculoskeletal tissues typically present with concomitant nonosseous metastases at the time of diagnosis. A 61-year-old male on 1-year remission, following transarterial chemoembolization of a 2.3-cm hepatic HCC 1 year before, presented with a 2-month history of left wrist pain and swelling after falling on an outstretched hand. Computed tomographic scan revealed diffuse osteolytic lesions localized in left hand and distal forearm, associated with equivocal diffuse activity on bone scan. Subsequent surgical debridement revealed metastatic hepatocellular carcinoma.

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). Methods: 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). Results: 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%; P = 0.223) and CTPA (asthma, 1.6%; nonasthma, 1.5%; P = 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%; P = 0.547) or CTPA (asthma, 0.6%; nonasthma, 0.6%; P = 0.796), nor was a history of asthma associated with a higher false-negative rate for VQ (asthma, 0.4%; nonasthma, 0.9%; P = 0.015) or CTPA (asthma, 1.9%; nonasthma 1.5%; P = 0.347). Conclusion: A history of asthma in the preceding 10 y was not associated with impaired diagnostic performance of PE imaging for either VQ or CTPA.

The rapid emergence of the COVID-19 pandemic has altered the risk–benefit calculus of many activities, including the practice of medicine. COVID-19 is caused by a single-strand RNA virus, SARS-CoV-2, belonging to the Coronaviridae family. The virus is known to infect the upper respiratory tract

This high quality meta-analysis by Tromeur et al. imparts great additional value to the recent Cochrane review on this topic of the evaluation of pulmonary embolism in pregnancy. Specifically, it is quite impressive that both computed tomography pulmonary angiography (CTPA) and ventilation-perfusion (VQ) imaging have a pooled negative predictive value of 100% and the pooled rates on non-diagnostic results are comparable in this population. We however differ regarding the maternal breast radiation exposure. There is an error in referencing Mitchell et al. in Table 4: the paper does not state the maternal effective doses at all for pregnant patients and the mean breast effective doses are incorrect. Mitchell et al. were able to reduce the mean breast dose from 7.64 mGy to 3.65 mGy utilizing a reduced 80 kV monitoring scan prior to the diagnostic scan. This paper does not give a dose range, thus approximately 50% of pregnant patients’ breast dose was more than 3.65 mGy. Low-dose perfusion imaging as described by Tromeur et al. utilizes 25% of a conventional perfusion dose, thus imparts 25% of the radiation to the maternal breast, maternal whole body and fetus: 0.16 mGy, 0.47 mGy and 0.02 mGy respectively. The CTPA maternal breast dose is at least 22 times higher than that of low dose perfusion imaging, and this is not insignificant given the increased breast mitotic rate during pregnancy. It is interesting that the short term breast cancer rate was not increased post CTPA. However, the majority of the CTPA patients were postpartum when the mitotic rate is normal, while the majority of patients who underwent VQ imaging were pregnant when the mitotic rate is increased. Limiting detection, screening has not yet begun for these cohorts. We agree that the fetal dose of both CTPA and VQ are negligible, but given the at least 22-fold increase in breast dose for CTPA, low-dose perfusion imaging is preferred in the setting of a normal chest radiograph. Renee M. Moadel, Jean-Ju Sheen, Leonard M. Freeman and Linda Broyde-Haramati

REPLY: We wanted to thank Karimzadeh and colleagues for their thoughtful comments on our editorial entitled, “Diagnostic Evaluation of Pulmonary Embolism During the COVID-19 Pandemic” ([1][1]). Perforce, any response to an evolving crisis will be based on incomplete data and best judgments.

This 33-year-old man presented with hemorrhagic stroke manifesting with left hemiparesis and right ptosis. Angiography revealed no patent carotids. The anterior and middle cerebral arteries were filling collaterally through the posterior vertebrobasilar pathway. The presumptive diagnosis was moyamoya disease. The etiology of the bleeding was right basilar tip aneurysm that subsequently had partial coil placement. Months later, the neck of the aneurysm perforated and second coiling was performed. Later on follow-up, patient developed left hand tremor. A radionuclide DATscan revealed total absence of right-sided basal ganglia activity. A possible etiology was occlusion of the middle cerebral artery's lenticulostriate branches.

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. Methods: 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. Results: 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% (n = 154) and CTPA in 37.1% (n = 91). Chest radiographs, performed in 96.3% (n = 236), were normal in 72.9% (n = 172). Imaging results for pulmonary embolism were negative in 88.2% (n = 216), positive in 4.1% (n = 10), and indeterminate in 7.8% (n = 19) with no difference between V/Q and CTPA (P = 0.63). Reimaging within 90 d occurred in 9.8% (n = 24), 14.7% (20/136) after initial V/Q, and 5% (4/109) after initial CTPA (P = 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 (P = 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. Conclusion: 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.

BACKGROUND: The symptoms of normal pregnancy overlap those of pulmonary embolism (PE). Limited literature suggests that low-dose perfusion scanning (LDQ), which yields lower maternal-fetal radiation exposure than CT pulmonary angiography (CTPA), performs well in excluding PE in pregnant patients. METHODS: We performed a retrospective cohort study of sequential pregnant women who underwent imaging for PE with LDQ or CTPA between 2008 and 2013 at Montefiore Medical Center. Our practice recommends LDQ for patients with negative results on chest radiographs. Patients were categorized according to initial imaging modality, and a subgroup analysis was performed in patients with asthma. The primary outcome was the negative predictive value (NPV) of imaging determined by VTE diagnosis within 90 days. RESULTS: Of 322 pregnant women (mean age, 27.3 +/- 6.3 years), initial imaging was positive for PE in 2.7% (6 of 225) of LDQs and 4.1% (4 of 97) of CTPAs, negative in 88.0% (198 of 225) of LDQs and 86.6% (84 of 97) of CTPAs, and indeterminate/nondiagnostic in 9.3% (21 of 225) of LDQs and 9.3% (9 of 97) of CTPAs (P - .79). Ten patients (3.1%) were treated for PE. The NPV was 100% for LDQ and 97.5% for CTPA. Subgroup analysis of patients with asthma (23.9% of this population) revealed a high likelihood of a negative study in the LDQ and CTPA groups (74.1% and 87.0%, respectively) and 100% NPV for both modalities. CONCLUSIONS: PE is an uncommon diagnosis in pregnancy. LDQ and CTPA perform well, with less maternal-fetal radiation exposure with LDQ. Therefore, when available, LDQ is a reasonable first-choice modality for suspected PE in pregnant women with a negative result on chest radiograph.

OBJECTIVE 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. CONCLUSION 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.