We included 321 consecutive patients presenting at Brest University Hospital in Brest, France, with clinically suspected PE and positive d-dimer or high clinical probability. Patients in whom VTE was deemed absent were not given anticoagulants and were followed up for 3 months.
Results
Detection of DVT by ultrasonography established the diagnosis of PE in 43 (13%). Lung scan associated with clinical probability was diagnostic in 243 (76%) of the remaining patients. MDCT scan was required in only 35 (11%) of the patients. The 3-month thromboembolic risk in patients not given anticoagulants, based on the results of the diagnostic protocol, was 0.53% (95% CI, 0.09-2.94).
Conclusions
A diagnostic strategy combining clinical assessment, d-dimer, ultrasonography, and lung scan gave a noninvasive diagnosis in the majority of outpatients with suspected PE and appeared to be safe.
Section snippets
Study Population and Enrollment
The eligible study population consisted of consecutive patients aged 18 years or older who were inpatients and outpatients seen at Brest University Hospital in Brest, France, between April 2004 and September 2006 with symptoms suggestive of PE. The hospital is a tertiary care center for a 300,000 population area. Clinical probability of PE was assessed by the physicians in charge according to the clinical model described by Wells et al7 on the basis of risk factors for VTE, symptoms and signs
Results
We included 321 patients with a median age of 72 years (range, 18-95 years). General characteristics of included patients are shown in Table 1.
Discussion
In this study, we found that using diagnostic strategy based on lung scan as the main imaging test safely excluded PE in inpatients and outpatients with suspected PE. The 3-month thromboembolic risk in patients in whom PE was ruled out on the basis of this diagnostic strategy was 0.53% (95% CI, 0.09-2.94). This 3-month thromboembolic risk is in line with what is observed after a negative pulmonary angiography9 and with the thromboembolic risk observed in recently published diagnostic
Acknowledgments
Author contributions:Dr Salaun: contributed to designing the study, managing imaging procedures, analyzing the data, and redacting the manuscript.
Dr Couturaud: contributed to designing the study, ensuring inclusion and follow-up of patients, analyzing the data, and redacting the manuscript.
Dr Le Duc-Pennec: contributed to designing the study, managing imaging procedures, and redacting the manuscript.
Dr Lacut: contributed to designing the study, ensuring inclusion and follow-up of patients,
Computed tomographic pulmonary angiography vs ventilation-perfusion lung scanning in patients with suspected pulmonary embolism: a randomized controlled trial
JAMA
(2007)
DJ Brenner et al.
Computed tomography—an increasing source of radiation exposure
N Engl J Med
(2007)
A Torbicki et al.
Guidelines on the diagnosis and management of acute pulmonary embolism: the Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC)
Eur Heart J
(2008)
There are more references available in the full text version of this article.
In this article the technique, interpretation, and diagnostic performance of scintigraphy for the diagnosis of acute pulmonary embolism (PE) are reviewed. Lung scintigraphy has stood the test of time as a reliable and validated examination for the determination of PE. Ventilation/perfusion (V/Q) lung scintigraphy assesses the functional consequences of the clot on its downstream vascular bed in conjunction with the underlying ventilatory status of the affected lung region, in contrast to CT pulmonary angiography (CTPA), which visualizes presence of the clot within affected vessels. Most-commonly used ventilation radiopharmaceuticals are Technetium-99m labeled aerosols (such as 99mTechnetium-DTPA), or ultrafine particle suspensions (99mTc-Technegas) which reach the distal lung in proportion to regional distribution of ventilation. Perfusion images are obtained after intravenous administration 99mTc-labeled macro-aggregated albumin particles which lodge in the distal pulmonary capillaries. Both planar and tomographic methods of imaging, each favored in different geographical regions, will be described. Guidelines for interpretation of scintigraphy have been issues by both the Society of Nuclear Medicine and Molecular Imaging, and by the European Association of Nuclear Medicine. Breast tissue is particularly radiosensitive during pregnancy due to its highly proliferative state and many guidelines recommend use of lung scintigraphy rather than CTPA in this population. Several maneuvers are available in order to further reduce radiation exposure including reducing radiopharmaceutical dosages or omitting ventilation altogether, functionally converting the study to a low-dose screening examination; if perfusion defects are present, further testing is necessary. Several groups have also performed perfusion-only studies during the COVID epidemic in order to reduce risk of respiratory contagion. In patients where perfusion defects are present, further testing is again necessary to avoid false-positive results. Improved availability of personal protective equipment, and reduced risk of serious infection, have rendered this maneuver moot in most practices. First introduced 60 years ago, subsequent advances in radiopharmaceutical development and imaging methods have positioned lung scintigraphy to continue to play an important clinical and research role in the diagnosis of acute PE.
2022, Nuclear Medicine and Molecular Imaging: Volume 1-4
Ventilation/Perfusion (V/Q) scintigraphy is a well-established test for pulmonary embolism diagnosis. Beside pulmonary embolism, the main clinical application of lung scintigraphy is pre-surgical assessment of lung cancer patients.
In lung cancer patients planned to undergo surgery, the prediction of post-operative lung function is a key step in the decision of whether to perform potentially lifesaving surgery in a patient who has an increased risk of peri-operative mortality or of post-operative impairment of lung function. In that respect, split lung function evaluation is required to estimate the fraction of lung function to be removed. Planar scintigraphy has been used for a long time to compute split lung function before pneumonectomy. More recently, the introduction of V/Q SPECT/CT has opened new perspectives to compute lobar split function before lobectomy.
In this article, the challenges associated with lung cancer surgery and the role of V/Q scintigraphy in predicting post-operative lung function and tailoring patient's management are reviewed.
Cancer therapy and progress in quality of imaging technologies for cancer surveillance and staging are in cause for the increase incidence of smaller incidental pulmonary embolism (PE). The clinical significance of incidental subsegmental pulmonary embolism (SSPE) is hard to define, balancing between possible false positive result, hypercoagulability signal, and truly venous thromboembolism (VTE) event. Evidence for optimal management of such findings are largely extrapolated from symptomatic SSPE in non-cancer patients and from symptomatic, more proximal PE in cancer patients. Current practice guidelines vary but some suggest withholding anticoagulation in selected patients. However, most SSPEs, incidental or not, should be treated as any other cancer-associated PE due to likely similar prognosis. Choice and duration of anticoagulation are extended from existing knowledge on more proximal PE.
Le diagnostic de l’embolie pulmonaire (EP) repose à l’heure actuelle sur l’utilisation séquentielle de tests diagnostiques, intégrés dans le cadre d’un algorithme ou d’une stratégie diagnostique, et non sur un test unique. L’étape initiale de ces stratégies diagnostiques est l’établissement de la probabilité clinique pré-test. Plusieurs scores validés sont à la disposition du clinicien pour permettre une évaluation standardisée et reproductible de la probabilité clinique, et représentent des outils diagnostiques fort utiles. En effet, de la probabilité clinique de base dépend la suite des investigations. En cas de probabilité clinique faible ou intermédiaire ou « unlikely », le dosage des D-dimères permet d’exclure le diagnostic d’EP chez 30 % des patients ambulatoires, sans recourir à une imagerie complémentaire. En cas de D-dimères positifs ou de probabilité clinique forte ou « likely », l’angioscanner multibarrettes est actuellement l’examen de choix. L’échographie de compression veineuse des membres inférieurs et la scintigraphie pulmonaire de ventilation/perfusion gardent toutefois toute leur place chez les patients ayant une contre-indication au scanner, en particulier les insuffisants rénaux. Par ailleurs, un nouveau test diagnostique, la tomoscintigraphie par émission monophotonique (TEMP) de ventilation/perfusion (V/P) ou single photon emission computed tomography (SPECT) semble être aussi performante que l’angioscanner, et pourrait représenter une alternative potentielle. Des études prospectives sont néanmoins nécessaires avant d’envisager son implémentation dans la pratique quotidienne.
The diagnosis of pulmonary embolism (PE) is nowadays based on the sequential use of several diagnostic tests rather than on a single test. These diagnostic strategies are safe and have been prospectively validated. The first step after identifying patients with suspicion of PE is to establish the pre-test clinical probability. Several scores are available in order to make a standardised and reproducible assessment of the clinical probability, and therefore represent precious diagnostic tools. Indeed, clinical probability guides further investigations. Indeed, in patients with a low or an intermediate clinical probability or an “unlikely” probability, PE can be safely ruled out by negative D-dimers in approximately one third of outpatients without additional imaging. In case of positive D-dimers and a high clinical probability or a “likely” clinical probability, CT pulmonary angiography is now the recommended imaging technique. However, lower limb venous compression ultrasound and ventilation/perfusion scans remain useful in patients with contra-indications to CT, mainly those with renal insufficiency. Finally, some novel diagnostic tests seem promising. For example, V/Q SPECT has arisen as a highly accurate test and a potential alternative to CTPA. However, prospective management outcome studies are still lacking and are warranted before its implementation in routine clinical practice.
That said, the ECG cannot be a primary diagnostic tool for PE due to the nonspecific nature of any ECG changes. Because a proximal DVT carries the greatest risk of PE,90 a compression ultrasonography (CUS) can be used to identify the presence and location of a DVT.10 When a DVT is present, the vein will not compress at the location of the thrombus.
Accurate, timely and cost-effective identification of pulmonary embolism remains a diagnostic challenge. This article reviews the pulmonary embolism diagnostic process with a focus on the best practice advice from the American College of Physicians. Benefits and risks of each diagnostic step are discussed. Emerging diagnostic tools, not included in the algorithm, are briefly reviewed.
