Investigation Of Pulmonary Embolism Diagnosis Research Articles

Clinicians' interpretation of ventilation/perfusion lung scan reports: Where are we today?

Clinicians' interpretation of lung scan reports will determine which further management decisions are taken when potentially fatal pulmonary embolism (PE) is suspected. To assess current referring clinicians' interpretation of the terminology used in ventilation/perfusion (V/Q) scan reports, whether this interpretation is affected by experience level, and how it affects clinical management decisions. This was a questionnaire-based cross-sectional study. Between September 2020 and May 2021, 300 questionnaires were distributed among clinicians who refer patients for V/Q scans. Of the 162 clinicians who responded, 94% thought that there is >85% likelihood of PE or definitely PE present when a scan is reported as 'high probability of PE'; 87% interpreted 'low probability of PE' as <10% likelihood of PE or definitely no PE present. Overall, >70% of clinicians across all experience levels correctly interpreted the intended meaning of probability categories according to the Modified Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) II criteria. Of the respondents, 77% agreed that clinically significant PE is ruled out by a normal scan. Further investigation for inconclusive findings, features of parenchymal lung disease and cardiomegaly were selected by 72%, 93% and 98% of clinicians, respectively. The findings of this study regarding high-probability scan results were in line with existing literature on lung scan report interpretation. However, our findings regarding low-probability scan results and negative V/Q scan specificity contrasted with the findings in these articles, suggesting that clinicians are now more familiar with lung scan interpretation guidelines. Experience level did not significantly affect interpretation of reports. Although most clinicians agreed that a negative scan excludes clinically significant PE, two-thirds of them would still subject the patient to further unnecessary investigations to exclude PE. What the study adds. Our findings regarding a low-probability ventilation/perfusion (V/Q) scan and the specificity of a negative V/Q scan contrasted with previous articles on lung scan interpretation, suggesting that clinicians are now more familiar with lung scan interpretation guidelines.Implications of the findings. Although most clinicians understood the negative predictive value of a V/Q scan, 20% would still investigate further with computed tomography pulmonary angiography or treat as confirmed pulmonary embolism. Education of clinicians about the negative predictive value of V/Q scans is important to avoid unnecessary radiation or anticoagulation.

Deep Learning-based Outcome Prediction in Progressive Fibrotic Lung Disease Using High-Resolution Computed Tomography.

Rationale: Reliable outcome prediction in patients with fibrotic lung disease using baseline high-resolution computed tomography (HRCT) data remains challenging. Objectives: To evaluate the prognostic accuracy of a deep learning algorithm (SOFIA [Systematic Objective Fibrotic Imaging Analysis Algorithm]), trained and validated in the identification of usual interstitial pneumonia (UIP)-like features on HRCT (UIP probability), in a large cohort of well-characterized patients with progressive fibrotic lung disease drawn from a national registry. Methods: SOFIA and radiologist UIP probabilities were converted to Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED)-based UIP probability categories (UIP not included in the differential, 0-4%; low probability of UIP, 5-29%; intermediate probability of UIP, 30-69%; high probability of UIP, 70-94%; and pathognomonic for UIP, 95-100%), and their prognostic utility was assessed using Cox proportional hazards modeling. Measurements and Main Results: In multivariable analysis adjusting for age, sex, guideline-based radiologic diagnosis, anddisease severity (using total interstitial lung disease [ILD] extent on HRCT, percent predicted FVC, DlCO, or the composite physiologic index), only SOFIA UIP probability PIOPED categories predicted survival. SOFIA-PIOPED UIP probability categories remained prognostically significant in patients considered indeterminate (n = 83) by expert radiologist consensus (hazard ratio, 1.73; P < 0.0001; 95% confidence interval, 1.40-2.14). In patients undergoing surgical lung biopsy (n = 86), after adjusting for guideline-based histologic pattern and total ILD extent on HRCT, only SOFIA-PIOPED probabilities were predictive of mortality (hazard ratio, 1.75; P < 0.0001; 95% confidence interval, 1.37-2.25). Conclusions: Deep learning-based UIP probability on HRCT provides enhanced outcome prediction in patients with progressive fibrotic lung disease when compared with expert radiologist evaluation or guideline-based histologic pattern. In principle, this tool may be useful in multidisciplinary characterization of fibrotic lung disease. The utility of this technology as a decision support system when ILD expertise is unavailable requires further investigation.

Frequency of computed tomography abnormalities in patients with chronic thromboembolic pulmonary hypertension: a comparative study between lung perfusion scan and computed tomography pulmonary angiography.

IntroductionChronic thromboembolic pulmonary hypertension (CTEPH) is one of the leading causes of pulmonary hypertension. Diagnosis of CTEPH can be established using various imaging techniques, including ventilation-perfusion scintigraphy (VQ) and multidetector computed tomography pulmonary angiography (CTPA). The aim of this study was to determine the frequency of direct pulmonary vascular, parenchymal lung, and cardiac abnormalities on CTPA in patients with CTEPH and to compare the diagnostic accuracy of both VQ scan CTPA in detecting CTEPH.MethodsWe retrospectively included 54 patients who had been referred for pulmonary hypertension service (20 males, 34 females). All patients had VQ scan and CTPA within 15 days and underwent pulmonary artery endarterectomy (PEA) thereafter. VQ scans were reported according to modified PIOPED (Prospective Investigation of Pulmonary Embolism Diagnosis) criteria. CTPA was considered as diagnostic for CTEPH if it showed presence of thrombus, webs, stenosis, or perfusion lung abnormalities.ResultsThe mean age of the study population was 41±10 years. The mean pulmonary artery pressure was 53±13 mmHg. Fifty-three out of 54 patients in the study population had high probability VQ scan and one patient had intermediate probability. CTPA was suggestive of CTEPH in all patients. The most frequent CTPA findings in the central pulmonary arteries and peripheral arteries were presence of thrombotic materials, abnormal vessel tapering and abrupt vessels-cut off (76% vs 65%, 67% vs 48%, and 48% vs 22%), respectively. The mosaic lung perfusion was present in 78% of the patients, and various cardiac morphology abnormalities were present and most common was abnormal right to left ventricle ratio (69%).ConclusionOur findings indicate that both VQ scan and CTPA are highly sensitive for the detection of CTEPH confirmed by PEA. Most CTEPH patients had several pulmonary vascular, parenchymal lung and cardiac abnormalities. There was no sign with 100% sensitivity on CTPA for CTEPH detection.

STUDY ON THE ROLE OF VENTILATION-PERFUSION SCAN IN DETECTION OF SILENT PULMONARY EMBOLISM IN NEPHROTIC SYNDROME CHILDREN

INTRODUCTION: Clinically silent pulmonary thromboembolism is commoner than symptomatic one in children with nephrotic syndrome. The present study was done to look for the occurrence of asymptomatic pulmonary thromboembolism in children with nephrotic syndrome using V IQ scan, which is noninvasive, cost effective. MATERIALS AND METHODS: This prospective study conducted at a tertiary care centre over a period of one year on one hundred children with nephrotic syndrome between the ages of 5 and 15 years with a median age of 8 years attending the Pediatric Nephrology Clinic were taken up for the study. Patients showing defect in Tc99m-MAA perfusion scintigraphy underwent ventilation scan within 24-48 hours. Scan ndings were interpreted by two nuclear medicine physicians independently who were unaware of illness of the patients. The results were interpreted according to Modied Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) criteria. The overall incidence of abnormal V/Q RESULTS: scan in our study was 14%. Individually the incidence was 13.9% in group I, 22.22% in group II and 3.6% in group III, which indicates that patients with steroid resistant and steroid sensitive nephrotic syndrome in relapse were prone to develop thromboembolic complications more than those who were in remission. Combined scintigraphic evidence of pulmonary thromboembolism was 18.05% in Groups I and II compared to 3.6% in controls (Group III). Patients with abnormal ventilation-perfusion scan showed s CONCLUSION: ignicantly larger (p&lt;0.05) duration of illness (mean 69.7±55.3 months) and signicantly greater degree (p&lt;0.001) of proteinuria as compared to patients with normal ventilation-perfusion scan who had mean duration of illness of 45.5±38.0 months.

Data That Support Removing the Mysticism for Radiologist's Performance of Cardiac CT and MRI.

Data That Support Removing the Mysticism for Radiologist's Performance of Cardiac CT and MRI.

Applying Wells score to inconclusive perfusion only modified PIOPED II (Prospective Investigation of Pulmonary Embolism Diagnosis II) readings in orderto optimize the lung scintigraphy diagnostic yield in acute pulmonary embolism detection.

When using perfusion only modified PIOPED II criteria for PE detection, generated non-diagnostic scans are found to be the main diagnostic restriction. The objective of current study is to identify the role of Wells criteria added to inconclusive readings with the intent of enhancing the lung scintigraphy diagnostic yield. CTPA was performed in 34 suspected PE patients with inconclusive lung scintigraphy. They also were evaluated by Wells score and classified as low, intermediate and high probability. Overall prevalence and the rate of PE for each probability were calculated. Furthermore, NPV for scores < 2 and PPV for scores > 6 were computed. Having a mean age of 59.75 ± 17.38years, 7 (20.6%), 23 (67.6%) and 4 (11.8%) of cases had total criteria point count < 2, 2-6 and > 6, respectively. Using CTPA, 5 patients (14.7%) were diagnosed with PE. None of the patients with scores < 2 had PE with an associated NVP of 100%. Patients with scores 2-6 had a PE rate of 4.3% and 100% of patients with scores > 6 were diagnosed with PE, implying that the PPV of scores > 6 was 100%. Adding Wells score to non-diagnostic scans allowed identification of PE to be done reliably, and provided further insight into how lung scintigraphy in conjunction with clinical assessment is a practical strategy not only for the patients unfit for performing CTPA but also in all the patients referred for PE evaluation.

A Clinically Meaningful Interpretation of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) II and III Data

This study aimed to calculate the multiple-level likelihood ratios (LRs) and posttest probabilities for a positive, indeterminate, or negative test result for multidetector computed tomography pulmonary angiography (MDCTPA) ± computed tomography venography (CTV) and magnetic resonance pulmonary angiography (MRPA) ± magnetic resonance venography (MRV) for each clinical probability level (two-, three-, and four-level) for the nine most commonly used clinical prediction rules (CPRs) (Wells, Geneva, Miniati, and Charlotte). The study design is a review of observational studies with critical review of multiple cohort studies. The settings are acute care, emergency room care, and ambulatory care (inpatients and outpatients). Data were used to estimate pulmonary embolism (PE) pretest probability for each of the most commonly used CPRs at each probability level. Multiple-level LRs (positive, indeterminate, negative test) were generated and used to calculate posttest probabilities for MDCTPA, MDCTPA + CTV, MRPA, and MRPA + MRV from sensitivity and specificity results from Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) II and PIOPED III for each clinical probability level for each CPR. Nomograms were also created. The LRs for a positive test result were higher for MRPA compared to MDCTPA without venography (76 vs 20) and with venography (42 vs 18). LRs for a negative test result were lower for MDCTPA compared to MRPA without venography (0.18 vs 0.22) and with venography (0.12 vs 0.15). In the three-level Wells score, the pretest clinical probability of PE for a low, moderate, and high clinical probability score is 5.7, 23, and 49. The posttest probability for an initially low clinical probability PE for a positive, indeterminate, and negative test result, respectively, for MDCTPA is 54, 5 and 1; for MDCTPA + CTV is 52, 2, and 0.7; for MRPA is 82, 6, and 1; and for MRPA + MRV is 72, 3, and 1; for an initially moderate clinical probability PE for MDCTPA is 86, 22, and 5; for MDCTPA + CTV is 85, 10, and 4; for MRPA is 96, 25, and 6; and for MRPA + MRV is 93, 14, and 4; and for an initially high clinical probability of PE for MDCTPA is 95, 47, and 15; for MDCTPA + CTV is 95, 27, and 10; for MRPA is 99, 52, and 17; and for MRPA + MRV is 98, 34, and 13. For a positive test result, LRs were considerably higher for MRPA compared to MDCTPA. However, both a positive MRPA and MDCTPA have LRs >10 and therefore can confirm the presence of PE. Performing venography reduced the LR for a positive and negative test for both MDCTPA and MRPA. The nomograms give posttest probabilities for a positive, indeterminate, or negative test result for MDCTPA and MRPA (with and without venography) for each clinical probability level for each of the CPR.

Low yield of ventilation and perfusion imaging for the evaluation of pulmonary embolism after indeterminate CT pulmonary angiography.

Ventilation and perfusion (VQ) imaging is common following suboptimal CT pulmonary angiogram (CTPA) for pulmonary embolism (PE) evaluation; however, the results of this diagnostic pathway are unclear. The purpose of our study is to determine the incidence of PE diagnosed on VQ scans performed in patients with suboptimal CTPAs. One hundred twenty-two suboptimal CTPAs with subsequent VQ scans within 1week were retrospectively identified. VQ reports utilizing modified​prospective investigation of pulmonary embolism diagnosis (PIOPED) and prospective investigative study of acute pulmonary embolism diagnosis (PISAPED) criteria were evaluated for presence of PE; intermediate probability, high probability, and PE present were considered PE positive. Three hundred consecutive reports of each diagnostic CTPA and diagnostic VQ studies were reviewed to estimate baseline PE positive rates at our institution. These were compared to the positive VQ scan rate after suboptimal CTPA by Fisher's exact test. Reported reason for suboptimal CTPA was noted. When contrast bolus timing was suboptimal, we measured main pulmonary artery (mPA) Hounsfield units (HU). Potential alternative diagnoses in CTPA reports were noted. 97.5% (119/122) of VQ scans following suboptimal CTPA were negative for PE, and 2.5% (3/122) were positive for PE. This was significantly lower than baseline PE positive rate of 10.7% (32/300, p<0.01) for VQ imaging, and 10.3% (31/300, p<0.01) for CTPA at our institution. Most (79.5%) CTPAs were suboptimal due to contrast timing. Average mPA density in these cases was 164±61HU. Most of these studies ruled out central PE. Potential alternative diagnosis was reported in 34/122 (28%) of suboptimal CTPAs, for which pneumonia accounted 59%. There is very low incidence of PE diagnosed on VQ imaging performed after suboptimal CTPA. This may be attributed to the ability of most suboptimal CTPAs to rule out central PE.

A Clinically Meaningful Interpretation of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) Scintigraphic Data

Pulmonary embolism (PE) is a common condition associated with significant morbidity and mortality. Diagnostic test characteristics reported in terms of sensitivity and specificity are difficult to translate at the clinical level. More relevant measures are likelihood ratios (LRs), which can convert a pretest into a posttest probability. The aim of our study was to calculate the LRs and posttest probabilities for multiple-level test result for ventilation/perfusion (V/Q) lung scintigraphy and for perfusion scintigraphy combined with chest radiography using modified Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) II and the Prospective Investigative Study of Pulmonary Embolism Diagnosis (PISAPED) criteria for each clinical probability level for the most commonly used clinical prediction rules (CPR) using the PIOPED data. PE pretest probability was estimated for the most commonly used CPRs (Wells, Geneva, Miniati, and Charlotte) at each clinical probability level (two-, three-, and four-level). Multiple-level LRs (high, indeterminate, low, very low probability, and normal) and the positive, indeterminate, and negative results for V/Q scintigraphy, and the positive, indeterminate, and negative results for perfusion scintigraphy were generated and used to calculate posttest probabilities based on the sensitivity and specificity data from PIOPED for each clinical probability level (low, intermediate, and high) for each CPR. Nomograms were also created. The LRs for a positive V/Q and perfusion scintigraphy test using modified PIOPED II and PISAPED criteria were 20.6, 11, and 23.7, and for a negative test result were 0.15, 0.16, and 0.2, respectively. In the three-level Wells score, the posttest probability for an initial low clinical probability PE for a positive, indeterminate, and negative test result, respectively, for V/Q scintigraphy is 56, 5, and 0.9; for perfusion scintigraphy with modified PIOPED 40, 7, and 0.9, and with PISAPED 59, not available (N/A), and 1.2; for an initial moderate clinical probability PE for V/Q scintigraphy 86, .22, and 4; for perfusion scintigraphy with modified PIOPED 77, 26, and 5, and with PISAPED 88, N/A, and 6; for an initial high clinical probability of PE for V/Q scintigraphy 95, 48, and 13; and for perfusion scintigraphy with modified PIOPED 92, 53, and 13, and with PISAPED 96, N/A, and 16. With LRs >10, a positive test result for V/Q and perfusion scintigraphy can confirm the presence of PE. Only a normal test result has low enough LR to exclude PE.

Modified PISAPED Criteria in Combination with Ventilation Scintigraphic Finding for Predicting Acute Pulmonary Embolism.

This prospective clinical study aimed at assessing three pulmonary scintigraphic algorithms to detect acute pulmonary embolism (PE): Lung ventilation/perfusion (V/Q) scintigraphy along with modified prospective investigation of pulmonary embolism diagnosis (PIOPED) criteria; lung perfusion scintigraphy along with prospective investigative study of acute pulmonary embolism diagnosis (PISAPED) criteria; and lung perfusion scan in combination with ventilation scan, along with modified PISAPED criteria, which were newly developed. Patients with suspicion of PE were eligible for this study if they had no abnormal chest x-ray. Their diagnostic workup included a clinical assessment, a pulmonary V/Q scintigraphy, and CT pulmonary angiography (CTPA), as well as a clinical outcome assessment over a period of 24 weeks. Referred to the final clinical diagnosis of patients, the sensitivity and specificity of each algorithm were evaluated. The diagnostic performance of each algorithm by the area under the maximum likelihood fitted receiver operating characteristic (ROC) curve was determined. With respect to the PISAPED criteria, the sensitivity was 60.8% and specificity was 87.3%. No patient was classified into nondiagnostic category. The PIOPED criteria showed that the sensitivity was 95.0% and specificity was 88.2%, while 57.4% of the patients were in nondiagnostic category. The areas under the ROC curve constructed from the PISAPED criteria results and the modified PIOPED criteria results were 0.734 and 0.859 (P < 0.01), respectively. The modified PISAPED criteria demonstrated that the sensitivity was 83.8% and specificity was 89.1%. No patient was classified into nondiagnostic category. The area under the ROC curve constructed from modified PISAPED criteria was 0.864 (P < 0.01). Perfusion scans used with ventilation scans and modified PISAPED criteria may increase the diagnostic accuracy of pulmonary scintigraphy for acute PE, compared with the two major algorithms.

Suspected Pulmonary Thromboembolism and Deep Venous Thrombosis: A Comprehensive 64-slice Multidetector Computed Tomography Diagnosis in Gynecologic Patients.

Suspected Pulmonary Thromboembolism and Deep Venous Thrombosis: A Comprehensive 64-slice Multidetector Computed Tomography Diagnosis in Gynecologic Patients.

Noncontrast Perfusion Single-Photon Emission CT/CT Scanning: A New Test for the Expedited, High-Accuracy Diagnosis of Acute Pulmonary Embolism

Standard ventilation and perfusion (V˙/Q˙) scintigraphy uses planar images for the diagnosis of pulmonary embolism (PE). To evaluate whether tomographic imaging improves the diagnostic accuracy of the procedure, we compared noncontrast perfusion single-photon emission CT (Q˙-SPECT)/CT scans with planar V˙/Q˙scans in patients at high risk for PE. Between 2006 and 2010, most patients referred for diagnosis of PE underwent both Q˙-SPECT/CT scan and planar V˙/Q˙scintigraphy. All scans were reviewed retrospectively by four observers; planar scans were read with modified Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) II and Prospective Investigative Study of Pulmonary Embolism Diagnosis (PISA-PED) criteria. On Q˙-SPECT/CT scan, any wedge-shaped peripheral perfusion defect occupying &gt; 50% of a segment without corresponding pulmonary parenchymal or pleural disease was considered to show PE. The final diagnosis was established with a composite reference standard that included ECG, ultrasound of lower-extremity veins, D-dimer levels, CT pulmonary angiography (when available), and clinical follow-up for at least 3 months. One hundred six patients with cancer and mean Wells score of 4.4 had sufficient follow-up; 22 patients were given a final diagnosis of PE, and 84 patients were given a final diagnosis of no PE. According to PIOPED II, 13 studies were graded as intermediate probability. Sensitivity and specificity for PE were 50% and 98%, respectively, based on PIOPED II criteria; 86% and 93%, respectively, based on PISA-PED criteria; and 91% and 94%, respectively, based on Q˙-SPECT/CT scan. Seventy-six patients had additional relevant findings on the CT image of the Q˙-SPECT/CT scan. Noncontrast Q˙-SPECT/CT imaging has a higher accuracy than planar V˙/Q˙imaging based on PIOPED II criteria in patients with cancer and a high risk for PE.

Anticoagulants for Cerebral Venous Thrombosis

See related article, p 8. Evidence relating to efficacy and safety of anticoagulants for CVT is only partially available from studies in the peer reviewed medical literature and from the corresponding authors of those studies. Consequently, this article is an opinion piece rather than a systematic review. Cerebral venous thrombosis (CVT) accounts for ≈0.5% of strokes and may occur at any age.1 Risk factors include pregnancy, oral contraceptives, head trauma, malignancy, infection, anemia, and dehydration. In older reports, the incidence of CVT was 3 to 4 per 1 million people per year in Europe and the United States.2 However, a survey published in 2012 found an incidence of CVT of 13.2 per 1 million people per year.3 With modern brain imaging technology, more cases are being discovered that probably would have resolved without medical intervention. Relative to pre-1990 clinical outcomes data, the average prognosis has dramatically improved.4,5 A Cochrane review of anticoagulant therapy for CVT4 based the recommendation in favor of using anticoagulation treatment (full-dose unfractionated heparin [UFH] or low-molecular-weight heparin [LMWH] followed by a vitamin K antagonist [VKA]) on 2 small randomized placebo-controlled trials (RCTs, n=79). These trials demonstrated a non-statistically significant reduction in deaths with anticoagulation (risk ratio, 0.33; 95% confidence interval [CI], 0.08–1.28). Subsequently, the European Federation of Neurological Sciences6 and the American Heart Association/American Stroke Association7 issued clinical practice guidelines calling for full-dose heparin acutely followed by VKAs for ≥3 months. The efficacy and safety of anticoagulants for CVT have not been comprehensively reviewed, with the inclusion of observational studies and the RCTs excluded from the Cochrane review. This review will evaluate published reports from 1990 to 2013 regarding the efficacy and safety of full-dose heparin (UFH or LMWH) during initial hospitalization and subsequent VKA treatment …

Diagnostic pathways in acute pulmonary embolism: recommendations of the PIOPED II investigators

BACKGROUND Pulmonary embolism (PE) is a potentially fatal disease. Diagnosis is challenging for clinicians because clinical presentation is variable and there is no diagnostic test that combines sufficiently high sensitivity and specificity to be used alone in clinically suspected PE. AIM OF THE STUDY PIOPED II investigators have formulated recommendations for the diagnostic approach to patients with suspected PE based on randomized trials. METHODS Diagnostic work-up recommendations were formulated based on the results of the Prospective Investigation of Pulmonary Embolism Diagnosis II and outcomes studies. RESULTS In many patients that present the combination of low or moderate clinical probability with negative D-dimer PE can be safely excluded. In other patients with suspected PE and positive D-dimer a CT angiography in combination with CT venography is recommended. PIOPED II investigators have also formulated recommendations for patients with suspected PE and allergy to iodinated contrast medium, with impaired renal function, and for women at fertile age and during pregnancy. In patients with discordant findings between clinical assessment and CTA o CTA/CTV, and with segmental or sub-segmental EP, further evaluation may be necessary and the diagnosis should be re-assessed. DISCUSSION AND CONCLUSIONS PIOPED II recommendations are of particular interest because consider, after the right clinical evaluation necessary for risk stratification of PE, the most recent, sensitive and specific imaging techniques for definitive diagnosis, such as CTA and CTV. D-dimer evaluation is recommended but, however, its low specificity is not underlined. The importance of combining CTA and CTV for a complete evaluation of the deep venous system is stated, but the difficulties of a routinary similar approach are not considered and alternative techniques, like compressive ultrasound and Colour Doppler ultrasound, are not proposed. The study faces also the issue of segmental and sub-segmental embolism, that presents a difficult clinical interpretation: the recommendations are, before starting the therapy, to re-evaluate and confirm the diagnosis, to avoid the risk of overtreatment.

Ventilation/Perfusion Scanning for Acute Pulmonary Embolism

Although the synthesis of ventilation-perfusion (V/Q) scan result and clinical pretest probability is vital to the diagnostic accuracy of V/Q scanning, there is no updated pretest/posttest tabular decision tool since that presented in the Prospective Investigation of Pulmonary Embolism Diagnosis I data. Because this verbal communication between the nuclear medicine physician and referring clinician is indispensable in this process, we sought to study the relationship between documentation of such communication (DCOMM) of the result of a V/Q scan and patient treatment outcome in patients with suspected acute pulmonary embolus (PE). Electronic medical records were searched for patients who underwent V/Q scan for the workup of acute pulmonary embolism from 2000 through 2009 at Harborview Medical Center in Seattle, Washington. Sin hundred eighty-two patients were included in the analysis. Ventilation-perfusion scan outcomes are reported categorically as normal (N), very low (V), low (L), intermediate (I), or high (H) probability. The distribution of V/Q results was 58 (N), 58 (V), 454 (L), 83 (I), and 29 (H). The treatment rates by group were 1.7% (N), 1.7% (V), 1.1% (L), 25.3% (I), and 96.6% (H). The rates of electronic documentation of communication between the nuclear medicine physician and referring physician were 16% (N), 22% (V), 19% (L), 30% (I), and 69% (H). In a logistic regression analysis, odds ratios for treatment relative to the N group were 1596 (P < 0.001) (H), 19 (P < 0.01) (I), and 0.63 (not statistically significant) (L). DCOMM predicted a higher rate of treatment, independent of the outcome of the V/Q scan. In a multivariate logistic regression, the odds ratio for treatment after DCOMM is 2.7 (P < 0.05) and increases to 4.8 (P < 0.01) when on-call studies are excluded. Review of 682 patients who underwent V/Q scan for suspected PE during 2000-2009 at a single institution demonstrates that DCOMM is a strong predictor of subsequent treatment for PE, across all probability outcomes. The results of this study demonstrate the potential effect of verbal communication from nuclear medicine physicians in this decision process, and a suggested precedent for critical results is presented.

Venous thromboembolism in cancer clinical trials: recommendation for standardized reporting and analysis

Carrier M, Khorana AA, Zwicker JI, Lyman GH, Le Gal G and Lee AYY on behalf of the subcommittee on Haemostasis and Malignancy for the SSC of the ISTH. Venous thromboembolism in cancer clinical trials: recommendation for standardized reporting and analysis. J Thromb Haemost 2012; 10: 2599–601.

Adherence to PIOPED II Investigators' Recommendations for Computed Tomography Pulmonary Angiography

BackgroundComputed tomography (CT) pulmonary angiography use has increased dramatically, raising concerns for patient safety. Adherence to recommendations and guidelines may protect patients. We measured adherence to the recommendations of Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED II) investigators for evaluation of suspected pulmonary embolism and the rate of potential false-positive pulmonary embolism diagnoses when recommendations of PIOPED II investigators were not followed. MethodsWe used a structured record review to identify 3500 consecutive CT pulmonary angiograms performed to investigate suspected pulmonary embolism in 2 urban emergency departments, calculating the revised Geneva score (RGS) to classify patients as “pulmonary embolism unlikely” (RGS≤10) or “pulmonary embolism likely” (RGS>10). CT pulmonary angiograms were concordant with PIOPED II investigator recommendations if pulmonary embolism was likely or pulmonary embolism was unlikely and a highly sensitive D-dimer test result was positive. We independently reviewed 482 CT pulmonary angiograms to measure the rate of potential false-positive pulmonary embolism diagnoses. ResultsA total of 1592 of 3500 CT pulmonary angiograms (45.5%) followed the recommendations of PIOPED II investigators. The remaining 1908 CT pulmonary angiograms were performed on patients with an RGS≤10 without a D-dimer test (n=1588) or after a negative D-dimer test result (n=320). The overall rate of pulmonary embolism was 9.7%. Potential false-positive diagnoses of pulmonary embolism occurred in 2 of 3 patients with an RGS≤10 and a negative D-dimer test result. ConclusionsNonadherence to recommendations for CT pulmonary angiography is common and exposes patients to increased risks, including potential false-positive diagnoses of pulmonary embolism.

Editorial introductions

Editorial introductions

Overutilization of CT Pulmonary Angiogram for Diagnosis of Pulmonary Embolism - Opportunities for Improvement

PURPOSE: Clinical manifestation of pulmonary embolism (PE) is non-specific and the physician's judgment is often inaccurate. Though CTPA (CT Pulmonary Angiography) is the gold standard, the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED II) study advocated conservative use of CTPA based on high pretest probability. However, despite the cost and complications, CTPA is often abused. The purpose of the study is to examine if CTPA was appropriately utilized based on Revised Geneva Score (RGS) and validated algorithm.

Influence of Population Prevalences on Numbers of False Positives: An Overlooked Entity

Disease prevalence alters the number of true positives (TP), true negatives (TN), false negatives (FN), and false positives (FP), even if the sensitivity and specificity of a test stays the same. We illustrate this using data for the detection of suspected acute pulmonary embolism (PE) from the Prospective Investigation of Pulmonary Embolism Diagnosis II (PIOPED II). We chose PE because of the clinical significance of the disease, the low prevalence of PE in the patient population being tested with CTPA with the widespread adoption of CTPA, and the serious clinical consequences of anticoagulation therapy in FP patients. Based on PIOPED II data (sensitivity 83%, specificity 96%), at a disease prevalence of approximately 5%, the number of FP patients is greater than the number of TP patients. Scaled to the US population, at a disease prevalence of 5%, there would be 139,800 FPs and 3,356,200 TNs. Assuming a mortality rate of 0.5% and a 3.0% rate of major bleeding secondary to anticoagulation therapy for well-controlled patients, if all FP patients received anticoagulation, there would be 699 deaths and 4194 major bleeding complications. At a prevalence of approximately 5% for PE, the number of FPs approaches or is greater than the number of TPs for CTPA for the detection of suspected acute PE. Patients with FP results may receive unnecessary, potentially harmful treatment with anticoagulation therapy. Population prevalence of disease needs to be taken into account along with the diagnostic accuracy of a test, because this may significantly affect downstream patient outcomes.