Suspicion Of Acute Pulmonary Embolism Research Articles

Comparison of Dual-Energy Computed Tomography Pulmonary Angiography-Derived Contrast Enhancement with Standard Dual-Energy Pulmonary Angiography in Diagnosing Subsegmental Pulmonary Embolism: A Prospective Study.

Objective In this study, we compare the diagnostic accuracy of dual-energy (DE) computed tomography pulmonary angiography (CTPA) derived contrast enhancement (DECTPA, CTPA images with iodine maps) with standard dual-energy pulmonary angiography (SCTPA) for diagnosis of subsegmental pulmonary embolism in the cases with clinical suspicion of acute pulmonary embolism (APE). Materials and Methods We included 50 cases with clinical suspicion of APE that were referred for CTPA. All the patients underwent CTPA in the dual-energy protocol. Two radiologists evaluated the images. The first radiologist interpreted the SCTPA images (vascular images) and the second radiologist interpreted the DECTPA (CTPA images with iodine maps) for findings of APE. We calculated the sensitivity, specificity, and negative predictive value of DECTPA vis-à-vis SCTPA images. Results The DECTPA with the advantage of iodine map utilization yielded higher detection of thrombi in peripheral subsegmental arteries (72 vs. 99; p = - 0.001) as compared to the SCTPA images by identification of 18 new perfusion defects (interquartile range [IQR]: 0-1) that were consistent with APE. Filling defects were identified in 27 (IQR: 0-4) more subsegmental arteries supplying these 18 areas, which were not detected on SCTPA alone. These 18 perfusion defects were identified in 13 cases. In these 13 cases, 4 new cases were diagnosed that were negative on CTPA ( p = -0.125). In the evaluation of the APE, sensitivity and specificity were calculated and it was found that DECTPA showed 100% sensitivity and 86% specificity with 100% negative predictive value in the detection of thrombi as compared to the routine CTPA. Conclusion DECTPA has higher sensitivity and negative predictive value in the detection of the subsegmental perfusion defect identification as compared to SCTPA.

Acute pulmonary embolism in a patient with hepatitis C virus infection and hepatocellular carcinoma: a case report

BackgroundCardiac metastases in hepatocellular carcinoma patients are infrequently encountered and usually associated with a very poor prognosis.Case presentationHereby, we report a case of an acute pulmonary embolism (PE) on top of HCC with direct cardiac invasion to the right atrium (RA) through the inferior vena cava with another metastasis to the right ventricular apex in the form of highly mobile cauliflower mass protruding through the tricuspid valve into RA and nearly obliterating right ventricular outflow tract in a multi-centric hepatocellular carcinoma patient.ConclusionAcute dyspnea in a patient with a long history of hepatitis C virus infection raises the suspicion of acute PE due to either hypercoagulable state induced by malignancy or by cardiac extension of the tumor which usually carries high mortality rates. To the best of our knowledge, this case is the first case in the literature to show cardiac metastases in HCC with two different pathological mechanisms.

A comparative analysis of the diagnostic performances of four clinical probability models for acute pulmonary embolism in a sub-Saharan African population: a cross-sectional study

BackgroundThe diagnosis of acute pulmonary embolism (PE) is one of the most challenging in emergency settings where prompt and accurate decisions need to be taken for life-saving purposes. Here, the assessment of the clinical probability of PE is a paramount step in its diagnosis. Although clinical probability models (CPM) for PE are routinely used in emergency departments (EDs) of low-resource settings, few studies have cited their diagnostic performances in sub-Saharan Africa (SSA). We aimed to comparatively assess the accuracy of four CPM in the diagnosis of acute PE in sub-Saharan Africans.MethodsWe carried out a cross-sectional study to compare the sensitivity, specificity, positive and negative predictive values and accuracy of four CPM namely; the Wells, simplified Wells, revised Geneva and the simplified revised Geneva (SRG) Scores to computed tomography pulmonary angiography (CTPA) in all adults patients with suspected PE admitted to the EDs of the Gynaeco-obstetric and Paediatric Hospital of Yaoundé and the Yaoundé Central Hospital in Cameroon between January 1, 2017 and April 30, 2018.ResultsIn total, we enrolled 30 patients with clinical suspicion of acute PE. PE was confirmed on CTPA in 16 (53.3%) cases. Their mean age was 53.7 ± 15.5 years and 36.7% were males. All four scores had a diagnostic performance superior to 50% in all criteria assessed. The simplified Wells score had the highest sensitivity (62.5%) followed by the Wells score (56.3%). The SRG score had the highest specificity (71.4%). The score with highest PPV was the SRG score (66.7%) and that with the highest NPV was the Wells score (56.3%). Overall the models with the highest accuracies were the Wells and SRG scores (60% for each).ConclusionAll CPM had a suboptimal diagnostic performance, perhaps highlighting the need of a more optimal CPM for acute PE in SSA. However, the Wells and the SRG scores appeared to be most accurate than the other two scores in the ED. Hence, both or either of them may be used in first intention to predict PE and guide which ED patients should undergo further investigations in an emergency SSA setting.

Tricuspid annular plane of systolic excursion to prognosticate acute pulmonary symptomatic embolism (TAPSEPAPSE study).

The imaging standard for evaluation of acute pulmonary embolism (PE) includes a computed tomography pulmonary angiogram. Ultrasonography has shown promise in obtaining the tricuspid annular plane systolic excursion (TAPSE) measurements, which may be of clinical importance in patients with acute PE. The objective of this study is to evaluate the diagnostic capability of TAPSE measurements for patients with suspicion for acute PE. We prospectively enrolled patients who came to the emergency department with suspicion of acute PE. Each patient underwent a point-of-care sonogram where a TAPSE measurement was obtained, followed by computed tomography pulmonary angiogram. Based on the computed tomography pulmonary angiogram findings, patients were grouped into 3 categories: no acute PE, clinically insignificant acute PE, or clinically significant acute PE. We enrolled 87 patients in this study. Twenty-three (26.4%) of these patients were diagnosed with PE. Of patients with PE, 15 (65%) were found to have a clinically significant acute PE. Analysis of mean TAPSE measurements between patients with clinically significant acute PE and those with insignificant or no PE was 15.2 mm and 22.7 mm, respectively (P ≤ .0001). Following receiver operating characteristic curve analysis, optimum TAPSE measurement to identify clinically significant acute PE is 18.2 mm. A cutoff TAPSE measurement of 15.2 mm shows a sensitivity of 53.3% (95% confidence interval, 26.7%-80%) and a specificity of 100% (95% confidence interval, 100%-100%) for the diagnosis of a clinically significant PE. Our data suggest that TAPSE measurements less than 15.2 mm have a high specificity for identifying clinically significant acute PE.

Diagnostic value of QRS and S wave variation in patients with suspicion of acute pulmonary embolism

BackgroundThis study aimed to investigate the diagnostic value of QRS and S wave variation in patients admitted to the emergency department with suspicion of acute pulmonary embolism (APE). MethodComputerized tomographic pulmonary angiography (CTPA) was performed in 118 consecutive patients to evaluate patients with suspected APE, and 106 subjects with appropriate electrocardiogram and CT images constituted the study population. ResultsUsing CTPA, APE was diagnosed in 48.1% (n:51) of the study population. The comparison of patients with APE and those without APE revealed that increased heart rate, right axis deviation of QRS axis, complete or incomplete right bundle branch block, prominent S wave in lead D1, increased QRS duration, percentage of QRS (9,8[4,8–19,0] vs 3,8[2,7–71]; p<0,001), S wave variation (22,3[9,6–31,9] vs 4,8 [2-8]; p<0,001) and ΔS wave amplitude (1.1[0.5–1.5] vs 0.2[0.1–0.5]; p<0.001) were significantly associated with APE, but no relationship was detected with respect to the presence of atrial arrhythmias, clockwise rotation of the horizontal axis, fragmentation, ST segment deviation, T wave inversion, and S1Q3T3 and S1S2S3 patterns. The percentage of S wave variation (OR: 1072 per 1% increase, 95% CI:1011–1137) was found to be an independent predictor of APE. ΔS wave amplitude>0.5mm predicted APE with a sensitivity of 72.6% and a specificity of 74.6% (AUC:0.805, 95% CI: 0.717–0.876; p<0.001). ConclusionThe present study demonstrated that QRS and S wave variation could be useful electrocardiographic signs for the diagnosis of APE.

¿Está indicada la angiografía por tomografía computarizada de las arterias pulmonares en pacientes con alta probabilidad clínica de tromboembolia pulmonar?

When a diagnostic test confirms clinical suspicion, the indicated treatment can be administered. A problem arises when the diagnostic test does not confirm the initially suspected diagnosis; when the suspicion is grounded in clinically validated predictive rules and is high, the problem is even worse. This situation arises in up to 40% of patients with high suspicion for acute pulmonary embolism, raising the question of whether CT angiography of the pulmonary arteries should be done systematically. This paper reviews the literature about this issue and lays out the best evidence about the relevant recommendations for patients with high clinical suspicion of acute pulmonary embolism and negative findings on CT angiography. It also explains the probabilistic concepts derived from Bayes’ theorem that can be useful for ascertaining the most appropriate approach in these patients.

Clinical and Demographic Predictors of Acute Pulmonary Embolism in Central Africa Using 64-Rows Multi-Detector Computed Tomography Angiography

&lt;p&gt;&lt;em&gt;Background: Acute pulmonary embolism is a life-threatening entity. Its diagnosis remains a challenge for clinicians and it is important to be aware of factors that increase risks of the disease. In this study, we access the clinical and demographic predictors of pulmonary embolism using 64-rows multi-detector Computed Tomography Angiography in central Africa.&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;Methods: From 01 January to 30 July 2016, the data record of patients who underwent chest 64-rows multi-detector Computed Tomography Angiography indicated for clinical suspicion of acute pulmonary embolism at Biamba Marie Mutombo Dikembe Hospital were retrospectively &lt;/em&gt;&lt;em&gt;were revisited and analyzed using logistic regression models.&lt;/em&gt;&lt;em&gt;&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;Results: Sixty-five consecutive patients (age range, 24 to 84 years and mean age 56.8 ± 14.9 years) were included with a female predominance. Pulmonary embolism was formerly detected in 17 patients (26.2% of cases). Age ≥ 65 years (OR = 9.5 CI 95%:14.74, 60.79, p = 0.018) and obesity (OR = 40.8 CI 95%:2.85, 58.44, p = 0.006) were the predictors of pulmonary embolism. Heart disease and pneumonia were the main pathologies associated and the main alternative diagnoses.&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;Conclusion: This study shows that age and obesity were independent predictors of PE. In central Africa&lt;/em&gt;&lt;em&gt; where Computed Tomography machine is not widely available,&lt;/em&gt;&lt;em&gt; aged and obese patients&lt;/em&gt;&lt;em&gt; with a clinical suspicion of pulmonary embolism&lt;/em&gt;&lt;em&gt; &lt;/em&gt;&lt;em&gt;should be dealt with as a higher suspicion of true &lt;/em&gt;&lt;em&gt;pulmonary embolis&lt;/em&gt;&lt;em&gt;m.&lt;/em&gt;&lt;em&gt; &lt;/em&gt;&lt;/p&gt;

Elevated d-dimer cut-off values for computed tomography pulmonary angiography—d-dimer correlates with location of embolism

Acute pulmonary embolism (APE) is a potentially fatal condition, and making a timely diagnosis can be challenging. Computed tomography pulmonary angiography (CTPA) has become the modality of choice, and this contributes to the increasing load on emergency room CT scanners. Our purpose was to investigate whether an elevated d-dimer cut-off could reduce the demand for CTPA while maintaining a high sensitivity and negative predictive value (NPV). We retrospectively reviewed all patients referred for CTPA with suspicion of APE in 2012, and collected d-dimer values and CTPA results. We investigated the diagnostic performance of d-dimer using a 0.5 mg/L cut-off and an age adjusted cut-off. We also evaluated a new and elevated cut-off. Cases were categorized according to their CTPA result into: no embolism, peripheral embolism, lobar embolism and central embolism. Finally we investigated a possible correlation between d-dimer values and location of embolism. We included 1,051 CTPAs, from which 216 (21%) showed pulmonary embolism. There were concomitant d-dimer analyses in 822 CTPA examinations. The current 0.5 mg/L cut-off achieved a sensitivity and NPV of 99%. The age-adjusted cut-off achieved a sensitivity and NPV of 98%, and our suggested cut-off of 0.9 mg/L achieved a sensitivity and NPV of 97%. We conclude that the elevated d-dimer cut-off of 0.9 mg/L achieved a high sensitivity and NPV, while reducing the number of CTPA by 27%. The correlation between d-dimer values and location of embolisms supports the suggestion of an elevated d-dimer value.

Beyond arterial gases: the role of lactates in risk stratification in pulmonary embolism

Background and aim: Lactic acid is a well established early marker of tissue hypoperfusion and it can be used as a therapeutical target. It usually measured on every patient with suspicion of acute pulmonary embolism. However, its prognostic significance in this setting is unknown. We aimed to determine whether arterial lactate was associated with in-hospital mortality in patients with PE. Methods: We retrospectively analyzed 193 patients (mean age 72.63±16.64 years; 47.2% male) admitted to our emergency department with acute PE between January and December 2010. Arterial blood was immediately collected after patient admission and the sample was processed within 15 minutes. Clinical, laboratorial and follow-up data was collected; the endpoint was in-hospital mortality. Results: Mean lactate level was 1.91±1.73. The best cut-off value (2.5 mmol/L) had an area under the ROC curve of 0.758 and a sensitivity of 57.1% and a specifity of 86.6%. Regarding the demographic and clinical data, we haven't found any significant difference between patients with lactate levels > 2.5 mmol/L and patients with lactate levels ≤ 2.5 mmol/L. Nevertheless, patients with lactate levels > 2.5 mmol/L had higher levels of BNP (570 vs. 221, p < 0.001), troponin (0.82 vs. 0.24, p < 0.001) and LDH (189 vs. 164, p=0.031). A value over 2.5 mmol/L was associated with an increased hazard ratio of 1.294 (95% CI: 1.052 – 1.590, p = 0.015) of in-hospital mortality. Conclusion: An only slighlty elevated arterial lactate level, collected immediately after admission, is a specific predictor of in-hospital mortality and may help in early triage of higher-risk patients.

Acute pulmonary embolism in the era of multi-detector CT: a reality in sub-Saharan Africa

BackgroundThe advantages of multi-detector computed tomography (MDCT) have made it the imaging modality of choice for some patients with suspected cardiothoracic disease, of which pulmonary embolism (PE) is an exponent. The aim of this study was to assess the incidence of PE in patients with clinical suspicion of acute PE using MDCT in a sub-Saharan setting, and to describe the demographic characteristics of these patients.MethodsConsecutive records of patients who underwent MDCT pulmonary angiography for suspected acute PE over a two-year period at the Radiology Department of a university-affiliated hospital were systematically reviewed. All MDCT pulmonary angiograms were performed with a 16-detector computed tomography (CT) scanner using real-time bolus tracking technique. Authorization for the study was obtained from the institutional authorities.ResultsForty-one MDCT pulmonary angiograms were reviewed of which 37 were retained. Of the 4 excluded studies, 3 were repeat angiograms and 1 study was not technically adequate. Twelve of 37 patients (32.4%) had CT angiograms that were positive for PE, of which 7 were males. The mean age of these patients was 47.6±10.5 years (age range from 33 to 65 years). Twenty five patients out of 37 (67.6%) had CT angiograms that were negative for PE. Eleven PE-positive patients (91.7%) had at least 1 identifiable thromboembolic risk factor whilst 5 PE-negative patients (20%) also had at least a thromboembolic risk factor. The relative risk of the occurrence of PE in patients with at least a thromboembolic risk factor was estimated at 14.4.ConclusionAcute PE is a reality in sub-Saharan Africa, with an increased likelihood of MDCT evidence in patients with clinical suspicion of PE who have at least a thromboembolic risk factor. The increasing availability of MDCT will help provide more information on the occurrence of PE in these settings.

Magnetic resonance imaging for diagnosis of acute pulmonary embolism: not yet a suitable alternative to CT‐PA

See also Revel MP, Sanchez O, Couchon S, Planquette B, Hernigou A, Niarra R, Meyer G, Chatellier G. Diagnostic accuracy of magnetic resonance imaging for acute pulmonary embolism: results of the ‘IRM-EP’ study. This issue, pp 743–50; and Sodhi KS, Saxena AK. Diagnostic accuracy of computed tomography pulmonary angiography and magnetic resonance imaging for an acute pulmonary embolism. This issue, pp 961.

Update on techniques for the diagnosis of pulmonary embolism

The clinical suspicion of acute pulmonary embolism (PE) is frequently raised. However, the diagnosis of PE is confirmed in only 20 - 30% of these patients. The high incidence in addition to the potential harm from false-positive or false-negative diagnostic decisions underline the importance of a standardised diagnostic algorithm with high sensitivity as well as specificity. This article reviews the diagnostic tests for the diagnosis of PE. This review provides an overview of the different clinical decision rules (CDRs), D-dimer tests and imaging techniques in patients suspected of PE. Furthermore, the diagnostic process in patients with clinically suspected recurrent PE, suspicion during pregnancy and new research areas are discussed. Various diagnostic tests are available to detect or exclude PE with good accuracy. CDRs and D-dimer tests play an important role in the exclusion of PE. Neither is sufficient as a single test, but the combination of an 'unlikely' clinical prediction and a normal D-dimer test result safely excludes PE. In case of a high CDR score and/or an elevated D-dimer concentration, extra imaging is necessary with multi-slice computed tomography pulmonary angiography as first choice modality.

Triple Rule-Out CT in Patients with Suspicion of Acute Pulmonary Embolism: Findings and Accuracy 1

The aim of this study was to prospectively investigate the diagnostic value of triple rule-out computed tomography (CT) in patients suspected of having acute pulmonary embolism (PE). A total of 125 patients with suspicion of PE, of whom 14 patients had the additional clinical suspicion of acute aortic syndrome, underwent electrocardiogram-gated triple rule-out dual-source CT. The contrast media application protocol was adjusted to obtain a homogenous attenuation of the pulmonary arteries, thoracic aorta, and coronary arteries. The diagnostic performance of triple rule-out CT was assessed by using adjudicated discharge diagnoses as reference standards. A total of 161 adjudicated cardiovascular discharge diagnoses were made in the 125 patients (including all true-positive and true-negative findings): acute PE was found in 26 (21%) and was excluded by CT in 99 (79%), coronary artery disease was found in 3 (3%) and was excluded by catheter angiography in 9 (6%), left ventricular systolic dysfunction was found in 2 (2%) and was excluded by echocardiography in 8 (6%), and acute aortic syndrome was found in 5 (4%) and was excluded by CT in 9 (7%) patients. Nonvascular chest disease was found in 34 (27%) and included pneumonia (n = 17), neoplasms (n = 5), fractures/osteolysis (n = 3), pericarditis (n = 2), and post-pneumonectomy syndrome (n = 1). Triple rule-out CT was normal in 53 (42%) patients. Overall sensitivity, specificity, and positive and negative predictive value of triple rule-out CT for cardiovascular disease were 100% (95% confidence interval [CI] 90-100%), 98% (95%CI 94-100%), 95% (95%CI 82-99%), and 100% (95%CI 97-100%, respectively). Triple rule-out CT is feasible in patients with suspicion of PE, reveals a wide range of vascular and non-vascular chest disease, and offers an excellent overall diagnostic performance.

MDCT of 220 consecutive patients with suspected acute pulmonary embolism. Incidence of pulmonary embolism and of other acute and nonacute thoracic findings

Purpose: This study was undertaken to evaluate the incidence of pulmonary embolism (PE) and other clinically relevant thoracic findings discovered on contrast-enhanced multidetector computed tomography (MDCT) examination in patients with a suspicion of acute PE.

MDCT of 220 consecutive patients with suspected acute pulmonary embolism: incidence of pulmonary embolism and of other acute or non-acute thoracic findings

This study was undertaken to evaluate the incidence of pulmonary embolism (PE) and other clinically relevant thoracic findings discovered on contrast-enhanced multidetector computed tomography (MDCT) examination in patients with a suspicion of acute PE. We retrospectively reviewed 220 reports of 40-row MDCT exams in consecutive patients (101 men, 119 women; mean age 55 years+/-18) suspected for acute PE. Presenting symptoms and risk factors were recorded. Image quality and incidence of PE and other clinically relevant thoracic findings were evaluated. MDCT were diagnostic in 96.8% of patients. Nineteen patients (8.6%) were positive for PE. Signs and symptoms were present in 82.7% (182) and risk factors in 38.2% (84) of the population. Clinically relevant thoracic findings were detected in 45.9% (101) of the patients. Ten patients had PE and other thoracic findings. Half of the patients (110) had neither PE nor other clinically relevant thoracic findings. Chest MDCT, with an excellent overall image quality, provided an explanation for the clinical presentation in about 50% of emergency department patients studied and was useful in detecting PE and other thoracic diseases with symptoms mimicking PE. However, half of the exams were negative.

Validity of echocardiography in non-invasive diagnosis of acute pulmonary embolism (author's transl)

M-mode echocardiography was used in 66 consecutive patients with a clinical suspicion of acute pulmonary embolism. It could be ascertained in 30 patients using pulmonary angiography and in 19 using lung scintigraphy. When pulmonary embolism had effects on haemodynamics, an end-diastolically enlarged right ventricle, a diminished left ventricle, reduced closing velocity of the anterior mitral valve cusp and paradox septum movement were seen in precordial echocardiography (n = 18). The relation of end-diastolic diameter of the right ventricle to the left ventricle correlated with the angiographic severity of pulmonary embolism (r = 0.78). In patients with acute pulmonary embolism and pulmonary hypertension a significant enlargement of the right pulmonary artery was found in the suprasternal beam direction when compared with patients without pulmonary hypertension (14.7 +/- 2.2 mm/m2 body surface vs 11.0 +/- 1.2 mm/m2 body surface; P less than 0.01). The index width of the right pulmonary artery of all patients correlated with the mean pulmonary artery pressure (r = 0.84). In one patient a thrombus in the right pulmonary artery could be demonstrated by suprasternal echocardiography. Haemodynamically effective pulmonary embolisations in patients without cardiopulmonary history can be diagnosed using echocardiography.

Acute pulmonary embolism: comparison and integration of perfusion lung scintigraphy with multislice spiral CT

This study compared and integrated the data from perfusion lung scintigraphy and multislice computed tomography (CT) for the emergency diagnosis of acute pulmonary embolism in nuclear medicine and radiology departments operating around the clock. One hundred and seven patients with a clinical and laboratory suspicion of acute pulmonary embolism who had already undergone chest radiography were divided into four groups according to the time interval between onset of clinical suspicion and performance of the two diagnostic examinations (0-24 h, 24-48 h, 0-48 h, 2-7 days). Cohen's test for the analysis of statistical concordance was used. Perfusion lung scintigraphy and multislice CT were positive in 29/107 (27.1%) and negative in 78/107 (72.89%). Positive concordance (PC) was found in 22 cases and negative concordance (NC) in 71 cases: 0-24 h: PC in 12, NC in 32 cases; 24-48 h: PC in 3, NC in 15 cases; 0-48 h: PC in 15, NC in 47 cases; 2-7 days: PC in 7, NC in 24 cases. Perfusion lung scintigraphy and multislice CT demonstrated elevated concordance if performed within 7 days of the onset of suspicion of acute pulmonary embolism. Concordance was higher if the examinations were completed within 24-48 h. In suspected acute pulmonary embolism, it is mandatory to reach a correct diagnosis within few hours--48 at the most.

Value of D-Dimer Testing in Acute Aortic Dissection

To the Editor: We read with great interest the recent review on etiology, diagnosis and management in aortic dissection.1 In their discussion on diagnostic strategies, the authors state that useful biomarkers for aortic dissection are currently absent. We recently reported on 24 patients with acute aortic dissection in whom D-dimer, a degradation product of cross-linked fibrin, was tested as a part of the initial diagnostic strategy.2 We found that, actually, all patients with acute aortic dissection …

Clinical Outcome After a Negative Spiral CT Pulmonary Angiographic Finding in an Inpatient Population From Cardiology and Pneumology Wards

The purpose of this study was to assess the clinical follow-up of a negative spiral CT (SCT) angiographic finding after a suspicion of acute pulmonary embolism (PE) in a population of inpatients with cardiac and/or respiratory disease. In this high-risk population, clinical findings suggestive of PE are frequently misleading. One hundred seventy-five consecutive patients hospitalized in cardiac and pneumology wards underwent SCT angiography for suspected PE over a 30-month period. Angiographic findings were positive in one third. For the 117 patients with negative SCT angiographic findings, a clinical follow-up during a minimum of 6 months was assessed, particularly in relation to recurrent thromboembolism, mortality, and cause of death. The mean +/- SD follow-up was 21 +/- 11.5 months, and five patients were unavailable for follow-up. Of the 117 patients with negative findings, 81 patients did not receive anticoagulant therapy and 46 patients received anticoagulation for cardiac disease or deep venous thrombosis. Twenty-two patients died during the follow-up period, 3 of them during the first 3 months following the initial event from an undetermined cause. In patients still alive, a new PE occurred in two cases. Patients with a poor cardiopulmonary reserve did not present any recurrent events. In this population, tests other than imaging (d-dimers, cardiac echocardiography, or venous ultrasound) contributed little to eliminate the diagnosis of PE. Whether or not early deaths are considered or not to be related to a recurrent PE, the rate of recurrence after a negative SCT angiographic finding varied between 1.8% and 4.9%. SCT angiography can be used confidently to rule out significant PE, and may prevent further investigations and unnecessary treatment in an inpatient population with cardiac and/or respiratory diseases.

Fractal Texture Analysis of Perfusion Lung Scans

The purpose of this study is to investigate if fractal texture analysis can assist in the diagnostic interpretation of perfusion lung scans. Forty-five perfusion scans were acquired from patients with clinical suspicion of acute pulmonary embolism (PE) who underwent pulmonary angiography for final diagnosis. Fractal texture analysis was performed on 270 regions of interest (ROIs) extracted from the posterior view of the lung scans. Specifically, there were 94 normally perfused ROIs and 176 abnormal ROIs representing various lung diseases including PE and obstructive pulmonary disease (OPD). The average fractal dimension (FD) of normal ROIs was statistically significantly higher than that of abnormal ROIs. Furthermore, the FDs of abnormal ROIs with PE were significantly lower than the FDs of ROIs with OPD present.