Ventilation-perfusion Scan Research Articles

"Guiding lights" for the diagnosis of chronic thromboembolic pulmonary hypertension in the flow of patients with pulmonary embolism

On December 13, 2021, an expert council was held to determine the position of experts of different specialties regarding the reasons for the low level of diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH) in real clinical practice in a pandemic of a new coronavirus infection and possible ways to improve detection in patients with pulmonary embolism (PE) ) in history. The reasons for the low level of diagnosis of CTEPH are the insufficient level of knowledge of specialists, especially primary care physicians; lack of clear regulatory documents and expert centers for the management of this category of patients. Primary diagnosis of CTEPH in a pandemic can be strengthened through the widespread use of telemedicine for consultations of primary care physicians with specialists from expert centers; to maximize the role of echocardiography and computed tomography (CT) as differential diagnostic tools for dyspnea, in particular in patients with COVID-19. To increase the detection rate of CTEPH, diagnostic vigilance is required in patients with risk factors and episodes of venous thromboembolism. To improve the screening of CTEPH, it is necessary to create an algorithm for monitoring patients who have had PE; provide educational activities, including through the media; create materials for patients with accessible information. The regulatory documents should designate the circle of responsible specialists who will be engaged in long-term monitoring of patients with PE. Educational programs are needed for primary care physicians, cardiologists, and other physicians who come into the field of view of patients with CTEPH; introduction of a program to create expert centers for monitoring and managing patients with the possibility of performing ventilation-perfusion lung scintigraphy, cardiopulmonary stress test, CT, right heart catheterization. It seems important to build cooperation with the Ministry of Health of Russia in order to create special protocols, procedures for managing patients with PE and CTEPH.

SWYER JAMES: A SHIFT IN THE DIAGNOSIS

SWYER JAMES: A SHIFT IN THE DIAGNOSIS

A CASE OF SARS-COV-2 ASSOCIATED WITH QUADRUPLE BACTERIAL COINFECTION

A CASE OF SARS-COV-2 ASSOCIATED WITH QUADRUPLE BACTERIAL COINFECTION

RADIOGRAPHIC FINDINGS OF CHRONIC THROMBOEMBOLIC PULMONARY HYPERTENSION

RADIOGRAPHIC FINDINGS OF CHRONIC THROMBOEMBOLIC PULMONARY HYPERTENSION

ANATOMICALLY SUSTAINABLE VARIATION OF UNILATERAL PULMONARY ARTERY AGENESIS (UPAA)

ANATOMICALLY SUSTAINABLE VARIATION OF UNILATERAL PULMONARY ARTERY AGENESIS (UPAA)

GOING WITH THE FLOW: A UNIQUE PRESENTATION OF EISENMENGER SYNDROME

GOING WITH THE FLOW: A UNIQUE PRESENTATION OF EISENMENGER SYNDROME

AMIODARONE THYROTOXICOSIS LEADING TO PULMONARY HYPERTENSION

AMIODARONE THYROTOXICOSIS LEADING TO PULMONARY HYPERTENSION

Perfusion-only imaging in pregnant women: A comparative reader study with implications for practice patterns.

This study seeks to understand the value of ventilation imaging in pregnant patients imaged for suspected pulmonary embolism (PE). Ventilation-perfusion (VQ) scans in this high-risk population were compared to ventilation-only scans. We hypothesize that in this relatively healthy population, the exclusion of ventilation scans will not impact the rate of scans interpreted as positive. This retrospective blinded comparative reader study on collated VQ scans performed on pregnant patients in the course of routine clinical care in a > 5 year period (03/2012 to 07/2017). Each set of VQ and perfusion only (Q) studies were reviewed by 8 readers (4 nuclear radiology fellows and 4 nuclear medicine faculty) in random order; the Q scans simply omitted the ventilation images. Readers recorded each study as PE, no PE, or non-diagnostic (prospective investigative study of acute PE diagnosis classifications). Logistic mixed effects models were used to test the association between scan type (VQ vs Q). 203 pairs of studies in 197 patients were included (6 patients had 2 scans). Subjects ranged from 14 to 45 years of age, with a median 28 years. A significant association between scan type and positive/negative classification. Q-scans received more positive classifications than VQ-scans (median of 7.6% vs 6.7%). No association was seen between scan type and positive/indeterminate classification, nor between scan type and negative/indeterminate classification. The exclusion of ventilation images in VQ-scans was associated with a higher rate of positive studies, but this difference was small (<1%). Given the overwhelmingly normal percentage of Q-exams (>90% in our study), and the benefits of omitting ventilation imaging, perfusion-only imaging should be considered a reasonable option for imaging the pregnant patient to exclude PE.

Identification and Follow-up of COVID-19 Related Matching Ventilation and Perfusion Defects on Functional Imaging Using VQ SPECT/CT.

PurposeAvailable clinical data have revealed that coronavirus disease 2019 (COVID-19) is associated with a risk of pulmonary microthrombosis and small airway disease. These patients present with varying degrees of perfusion abnormalities. The purpose of this study was to evaluate the use of a ventilation/perfusion single-photon emission computed tomography/computed tomography (VQ SPECT/CT) in the detection and follow-up of persistent lung perfusion abnormalities that were suspected to be due to pulmonary microthrombosis, small airway disease, or both.Methods A retrospective study was conducted at the department of nuclear medicine of Universitas Academic Hospital in Bloemfontein, South Africa. We reviewed the studies of 78 non-hospitalized patients with COVID-19 infection referred to our department from July 2020 to June 2021 for a perfusion only SPECT/CT study or a VQ SPECT/CT study. Pulmonary embolism was suspected in all 78 cases.ResultsSeventy-eight patients were studied. The median (interquartile range) age was 45 (41–58) years, and the majority (n = 69; 88.5%) were females. Twenty-two (28.2%) of these patients had matching VQ defects with mosaic attenuation on CT. All nine of the patients who had follow-up studies had these abnormalities persistently, even after 1 year.ConclusionWe confirm that the VQ scan is a safe and effective tool to identify and follow-up recovered COVID-19 patients with persistent ventilation and perfusion abnormalities suspicious of small airway disease and pulmonary microthrombosis.

Interobserver Variability in Interpretation of VQ SPECT and its Impact on Patient Management

Background: Pulmonary Embolism (PE) is a major cause of morbidity, mortality and hospitalization. Ventilation Perfusion lung scan (VQ) is a powerful tool in diagnosing PE. It has been noted that there are some variations between highly experienced physicians in interpreting VQ SPECT due to lack of widely accepted reporting guidelines. Aim of the Study: Is to measure the interobserver variability in interpreting VQ scans, and then re-measure it again after applying standardized guidelines. Methods: Two cohorts of patients were included in this study the first included 347 patients and the second 290. Interobserver variability between 4 experienced physicians was measured on the first cohort and re-measured on the second cohort after applying 10 points agreed standardized guidelines. Results: Showed substantial increase in the percentage of agreement between all the physicians after applying the agreed 10 points standardized diagnostic criteria. This was apparent in all the categories with the highest agreement achieved when comparing 2 physicians. Kappa value increased from 0.346 to 0.4665 between the 4 Physicians, from low 0.3 to high 0.4 range between 3 Physicians and from as low as 0.2762 to the maximum of 0.5516 between 2 physicians. Unclassified number decreased between the 2 cohorts from 16.5% to 8% and subsequently decreasing false positive cases from 7.5% to 1.7%. Conclusion: Adherence to reporting guidelines increases the interobserver agreement in interpreting VQ SPECT leading to better patient outcomes and increased referrer confidence in reporting VQ SPECT.

Multiorgan ultrasonographic findings in patients with pulmonary embolism at diagnosis and clinical follow-up: a proof of concept study.

The purpose of this descriptive feasibility study was to assess the clinical impact and feasibility of conducting a multiorgan ultrasound examination of patients with pulmonary embolism at both time of diagnosis and at clinical follow-up. Hemodynamically stable patients with pulmonary embolism verified by CT pulmonary angiography or ventilation perfusion scintigraphy were eligible for inclusion. Enrolled patients underwent multiorgan ultrasound investigation encompassing echocardiography supplemented with focused lung and deep venous ultrasound emphasizing right ventricular strain, subpleural consolidations and presence of deep venous thrombi. Identical investigations were conducted at 3months follow-up. The presence of ultrasonographic findings at diagnosis and follow-up was compared and the clinical impact of any remaining pathology or strain was described. Twenty-one patients were enrolled in the study of whom 20 survived to attend follow-up. Mean age was 62 ± 15years and 48% were female. At diagnosis, the most prevalent ultrasonographic findings were subpleural consolidations in 11 patients and right ventricular dilation in eight. At follow-up, signs of right ventricular strain had resolved in all patients. However, in one patient, no resolution was seen in a subpleural consolidation observed at the time of pulmonary embolism diagnosis, resulting in referral to a chest CT. Additionally, one patient exhibited residual deep venous thrombotic material, leading to prolongation of anticoagulative treatment. In patients with pulmonary embolism, multiorgan ultrasound is feasible in follow-up and adequately powered studies should determine the clinical utility of such an approach.

Imaging Advances in Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is an under recognized complication of pulmonary embolism with significant morbidity and mortality when left untreated. There have been ongoing advances in the treatment of CTEPH with potentially excellent outcomes for patients when diagnosed and treated in a timely fashion. Although ventilation-perfusion scintigraphy remains critical in screening for CTEPH, the radiologic diagnosis involves multiple modalities from digital subtraction angiography to high quality computed tomography pulmonary angiography. State of the art imaging in CTEPH now also includes dual energy computed tomography, lung subtraction iodine mapping, and magnetic resonance imaging.

PH Roundtable: Tailoring CTEPH Imaging for Evaluation and Postintervention Assessment—What Works and What’s New?

PH Roundtable: Tailoring CTEPH Imaging for Evaluation and Postintervention Assessment—What Works and What’s New?

Diagnostic Evaluation of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a distinct form of pulmonary hypertension, uniquely characterized by pulmonary artery narrowing and occlusion from clot material. With advances in medical education and therapeutic options, awareness of CTEPH has grown significantly in recent years. The diagnostic evaluation remains complex, warranting an integrated assessment of history, physical exam, echocardiogram, chest imaging including computerized tomography with angiography, ventilation–perfusion scanning, right heart catheterization, catheter-based pulmonary angiography, and assessment for medical and mechanical CTEPH risk factors. The diagnostic evaluation of CTEPH is reviewed here.

Chronic Thromboembolic Pulmonary Hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH), defined as precapillary pulmonary hypertension (PH) by right heart catheterization and imaging consistent with chronic thromboembolism, is a long-term complication of pulmonary embolism (PE). Pathobiological mechanisms involve pulmonary artery occlusion from organized thromboembolic material despite at least three months of uninterrupted therapeutic anticoagulation followingacute PE and secondary microvasculopathy. Delay in diagnosis and management of CTEPH is associated with poor outcomes. High clinical suspicion,comprehensiveassessment of residual dyspnea or exercise intolerance in the aftermath of PE andaccurate interpretation ofcomputed tomography pulmonary angiography (CTPA) are pivotal steps inthe diagnosis. Ventilation-perfusion (V/Q) scan is the preferred initial radiologicscreening tool as normal V/Q essentiallyrules outCTEPH. Any mismatched perfusion defect on the V/Q scan in the setting of PH or any finding compatible with chronic thromboembolism on CTPA should prompt referral to an expert CTEPH center. Once the diagnosis is verified, all eligible patients should be offered pulmonary thromboendarterectomy (PTE). Pulmonary vasodilators or balloon pulmonary angioplasty are safe and effective in inoperable or post-PTE persistent/recurrent CTEPH. During the course of their disease, a patient may receive a combination of treatments, at times consisting of all three strategies. Lifelong therapeutic anticoagulation is recommended for CTEPH.

0829 Workup of Nocturnal Hypoxemia Leads to Diagnosis of Patent Foramen Ovale

Abstract Introduction Patent foramen ovale (PFO) in adults often remains asymptomatic until clinical manifestations such as cryptogenic stroke, migraine headache, air embolism, hypoxemia, or platypnea-orthodeoxia syndrome occur. In this case, prior workup of cryptogenic stroke failed to identify a PFO that was diagnosed after further investigation of polycythemia which revealed nocturnal hypoxemia on polysomnogram. Report of Cases: A 60-year-old male with history of recurrent venous thromboembolic events (VTE), secondary polycythemia, and cryptogenic strokes was referred for a polysomnogram during the evaluation of polycythemia. Over the span of six years, he had multiple cryptogenic strokes and VTEs in the setting of polycythemia and normal hypercoagulability labs. Further evaluation suggested secondary polycythemia after serum erythropoietin and JAK2 mutation testing were negative. The patient was a never smoker without evidence of malignancy or renal disease leading to suspicion that his polycythemia was due to hypoxemia despite normal oxygen saturations during point of care evaluations. He frequently reported shortness of breath during appointments. During a polysomnogram, the patient was found to have a total apnea-hypopnea index of fewer than 5 events per hour but demonstrated hypoxemia with 49.7% of total sleep time spent below an oxygen saturation of 90%. He was referred to pulmonology for further evaluation that showed normal resting oxygen saturation, no desaturation on a six-minute walk test, mild restrictive defect on pulmonary function testing, and a normal chest computed tomography with angiography. Prior transthoracic echocardiogram had demonstrated an atrial septal aneurysm without communication between the atrial chambers. No evidence suggestive of a right-to-left shunt was found on lateral imaging of the brain during a ventilation-perfusion scan. Further evaluation of the aneurysmal atrial septum on transesophageal echocardiogram with an agitated saline bubby study demonstrated a patent foramen ovale with a right-to-left shunt. In the setting of hypoxia leading to secondary polycythemia, the patient was scheduled for PFO closure. Conclusion Hypoxemia out of proportion to sleep-disordered breathing on polysomnogram should prompt further evaluation. Despite multiple prior strokes, our patient’s PFO had gone undiagnosed until polycythemia prompted a polysomnogram that demonstrated isolated nocturnal hypoxemia and prompted a further workup. Clinically significant hypoxemia is an indication for PFO closure. Support (If Any)

C41 AN UNUSUAL CASE OF “PULMONARY EMBOLISM”

Abstract Background Pulmonary vein stenosis (PVS) is a complication of catheter–based radiofrequency ablation (RFA) for atrial fibrillation (AF), caused by a vascular response which leads to replacement of necrotic myocardium with collagen. Clinical presentation can mimic pulmonary embolism (PE) and usually appears some months after procedure. Case report A 65–year–old man was hospitalized in March 2021 with a complaint of worsening dyspnoea on exertion, over the course of one month. He had a past medical history of persistent atrial fibrillation, because of which he underwent four pulmonary vein ablations (both RFA and crioablation), the last one in 2019. The previous echocardiogram showed a high systolic pulmonary arterial pressure (sPAP of 75 + 5 mmHg) with normal right ventricular function and dimensions. Despite D–dimer at admission was negative, a CT pulmonary angiography was performed and showed occlusion of left superior pulmonary vein and a severe stenosis of right superior pulmonary vein; ventilation–perfusion scintigraphy (V/Q scan) demonstrated widespread decreased perfusion of both superior lung lobes. The patient underwent angioplasty of right pulmonary vein and after the procedure sPAP greatly decreased (35 mmHg). Discussion Despite its reduction in incidence and its short–term presentation from procedure, severe symptomatic pulmonary vein stenosis must be considered among complications of ablation for atrial fibrillation. Delayed symptoms can also present years after procedure, even if in literature few similar cases are described. Ventilation–perfusion scintigraphy is a very sensible method to assess the functional significance of pulmonary vein stenosis and it also relates with symptoms’ severity. It should be performed in case of a high clinical suspicion, considering that the characteristic ventilation–perfusion mismatch of this condition can be seen in other diseases too, over all pulmonary embolism. Conclusions This case report emphasizes the importance of a thorough anamnesis and an exact interpretation of diagnostic imaging to correctly identify this AF ablation complication and optimize the patient’s therapeutic management. It must be considered that PV stenosis can develop late and with unusual symptoms, mimicking other diseases, like pulmonary embolism, which has the same scintigraphic imaging.

Changes in Lung Perfusion in Patients Treated with Percutaneous Mechanical Thrombectomy for Intermediate-Risk Pulmonary Embolism

BackgroundCurrent pulmonary embolism treatment options rely heavily on anatomical clot location. However, anatomical location does not necessarily determine adverse outcomes; rather, clinical severity is secondary to the degree of perfusion impairment. Dual-energy computed tomography pulmonary angiogram (DE-CTPA) can map perfusion at the time of pulmonary embolism diagnosis. Single-photon emission computed tomography ventilation-perfusion scans allow for perfusion tracking similar to DE-CTPA. MethodsWe present 3 patients with intermediate-risk pulmonary embolism treated with mechanical thrombectomy using the Inari FlowTriever System (Inari Medical, Irvine, Calif). Lung perfusion scoring was applied to pre-procedure and post-procedure imaging. We graded perfusion of each lobe in 3 planes. If the entire lobe was perfused, a score of 3 was assigned. If lung perfusion is normal, total perfusion score is 15. All patients had pre-procedure and follow-up transthoracic echocardiograms. ResultsAll 3 patients were diagnosed with pulmonary embolism via DE-CTPA that showed right ventricle strain and had deep venous thrombosis. Following mechanical thrombectomy, patients immediately experienced improvement in perfusion score; scores continued to improve at follow-up. All patients also had improvement in right ventricle size or function on follow-up echocardiogram. DiscussionIntermediate-risk pulmonary embolism often has large initial clot burden that predicts residual pulmonary vascular obstruction. Residual pulmonary vascular obstruction is associated with increased risk of death, recurrent thrombus, and chronic thromboembolic pulmonary hypertension. Clot removal via thrombectomy may decrease the prevalence of residual pulmonary vascular obstruction by improving lung perfusion. We found that mechanical thrombectomy increased lung perfusion immediately and at follow-up assessments.

Feasibility of Single Lung Transplant for Post-COVID Fibrosis: A Case Report

IntroductionPreviously we reported bilateral lung transplantation is the last treatment option for irrecoverable COVID ARDS and post-COVID fibrosis. Now we report our first single lung transplant (SLTx) for post-COVID fibrosis.Case ReportA 59-year-old, never-smoker, female, with history of obstructive sleep apnea, hypertension and hyperlipidemia, presented to an outside hospital with COVID-19, shortness of breath, and bilateral pulmonary infiltrates on chest X-ray (CXR) (Figure 1a). She was admitted to the intensive care unit, never requiring intubation, for an overall 40-day hospitalization. At discharge, she had shortness of breath with minimal activity and required continuous oxygen (O2) therapy.One year later she presented to our institution for an outpatient lung transplant evaluation for her post-COVID fibrosis. Her cardiac work up was unremarkable, with the absence of pulmonary hypertension on echocardiogram and right heart catheterization. Computed Tomography of her chest showed only significant fibrosis in the upper lobes with traction bronchiectasis and volume loss (Figure 1c). Her lung ventilation perfusion scan showed grossly normal perfusion to both lungs. Thus, she was listed for left, right, and bilateral lungs with a Lung Allocation Score of 42.After 39 days of listing, she underwent left SLTx. Final pathology of her explanted lung (Figure 1d) showed both uninvolved lung parenchyma and interstitial fibrosis and capillary congestion (Figure 1e). Post-operatively, her course was unremarkable and she was discharged home on POD 19. She was seen in clinic on POD 22 and doing well with no need for supplemental O2 and improving CXR (Figure 1b).SummarySLTx can be used to treat debilitating post-COVID lung fibrosis when there is the absence of severe lung damage and pulmonary hypertension. Considering SLTx in these patients is necessary to expand the donor pool of lungs for a population of patients that will continue to grow with the continued COVID-19 pandemic.

Single Lung Transplantation for Pulmonary Fibrosis Secondary to COVID-19

IntroductionAs of April 2021, 78 lung transplants (LTx) were performed for a diagnosis of COVID-19: 50 for COVID-19 ARDS and 28 for pulmonary fibrosis. Bilateral LTx has been recommended as many patients develop significant pulmonary hypertension. Additionally, native lung explants may include cavitary areas of pneumonia, which could serve as a nidus for infection. Single LTx (SLTx) can be considered in patients who have chronic pulmonary fibrosis secondary to COVID-19 with a short window to receive a transplant, or who would otherwise be considered for a single lung. There have been no published cases of a single lung transplant for COVID-19 pulmonary fibrosis. We present a case of a patient with pulmonary fibrosis from COVID-19 who underwent SLTx.Case ReportA 70yo male with O+ blood type was hospitalized 8/2020 to 10/2020 with COVID-19 pneumonia, treated with Remdesivir and Tocilizumab. He had hypoxia but never required intubation. His course was complicated by bilateral pneumothoraces requiring chest tubes. He developed pulmonary fibrosis requiring 6 L of oxygen at rest. CT scan of his chest showed multifocal, peripheral prominent ground glass opacities and interlobal septal thickening with traction bronchiectasis. Ventilation-perfusion scan demonstrated 22% perfusion to the left lung and 78% to the right lung. Right heart catheterization showed pulmonary artery pressures of 36/12 mmHg. His pulmonary function test was suggestive of restrictive disease (FEV 0.81 L [30%], FVC 0.96 L [27%], and FEV1/FVC 85%) that had worsened over time. He was presented at multidisciplinary review board with recommendation to list for left SLTx, which was activated August 2021. The patient was admitted in September 2021 and underwent left single lung transplant via left anterolateral thoracotomy, off cardiopulmonary bypass. Total ischemia time was 3:54. Explant pathology showed end stage pulmonary fibrosis. The patient was extubated on postoperative day 1 with an uneventful postoperative course. He was discharged to skilled nursing facility on postoperative day 26 for rehabilitation.SummarySLTxp is safe and feasible for COVID-19 related pulmonary fibrosis in well-selected patients who have a short window to receive a transplant.