Significance of inhalation and perfusion scintigraphy for the diagnosis of pulmonary embolism (author's transl)

Inhalation and perfusion scintigrams, general radiological examination of the thorax and an EKG were done on 43 patients with clinically suspected pulmonary embolism. In 11 cases, the clinical diagnosis could be confirmed on the basis of the scintigraphic examination. In the remaining 32 patients, an embolich event could be excluded by pulmonary scintigram, radiological examination and later the clinical course. A synopsis of clinical observations, X-ray and scintigraphy, therefore, permitted a basically reliable diagnosis of pulmonary embolism; selective pulmonary angiography should be used only in exceptional cases.     

Autopsy evidence of pulmonary thromboembolism

OBJECTIVE: To determine the prevalence of pulmonary thromboembolism (PE) and underlying risk factors at autopsy, compared with clinical diagnosis. DESIGN: Retrospective review of autopsy records, death certificates and medical histories. PATIENTS AND SETTING: All 132 patients who underwent autopsy at St Vincent's Hospital, Melbourne, in 1992. RESULTS: Sixteen cases (12% of autopsies) of PE were found at autopsy. In only two had PE been recorded on the death certificate; in one other, diagnosis had been made before death. Associated pulmonary infarction and/or haemorrhage was found in only six patients with PE. All 16 had at least one underlying risk factor: advanced age, cancer, heart disease, or recent pelvic or abdominal surgery. In four patients with missed PE, clinical records showed episodes consistent with PE. There were four false-positive diagnoses. CONCLUSIONS: Significant undiagnosed pulmonary embolism is not uncommon at autopsy. Many episodes are clinically silent, but the diagnosis should be suspected in at-risk patients with unexplained episodes of dyspnoea and tachycardia.     

Value of perfusion lung scan in the diagnosis of pulmonary embolism: results of the Prospective Investigative Study of Acute Pulmonary Embolism Diagnosis (PISA-PED)

To assess the value of perfusion lung scan in the diagnosis of pulmonary embolism, we prospectively evaluated 890 consecutive patients with suspected pulmonary embolism. Prior to lung scanning, each patient was assigned a clinical probability of pulmonary embolism (very likely, possible, unlikely). Perfusion scans were independently classified as follows: (1) normal, (2) near-normal, (3) abnormal compatible with pulmonary embolism (PE+: single or multiple wedge-shaped perfusion defects), or (4) abnormal not compatible with pulmonary embolism (PE-: perfusion defects other than wedge-shaped). The study design required pulmonary angiography and clinical and scintigraphic follow-up in all patients with abnormal scans. Of 890 scans, 220 were classified as normal/or near-normal and 670 as abnormal. A definitive diagnosis was established in 563 (84%) patients with abnormal scans. The overall prevalence of pulmonary embolism was 39%. Most patients with angiographically proven pulmonary embolism had PE+ scans (sensitivity: 92%). Conversely, most patients without emboli on angiography had PE- scans (specificity: 87%). A PE+ scan associated with a very likely or possible clinical presentation of pulmonary embolism had positive predictive values of 99 and 92%, respectively. A PE- scan paired with an unlikely clinical presentation had a negative predictive value of 97%. Clinical assessment combined with perfusion-scan evaluation established or excluded pulmonary embolism in the majority of patients with abnormal scans. Our data indicate that accurate diagnosis of pulmonary embolism is possible by perfusion scanning alone, without ventilation imaging. Combining perfusion scanning with clinical assessment helps to restrict the need for angiography to a minority of patients with suspected pulmonary embolism.     

Clinical and instrumental diagnosis of pulmonary embolism

Pulmonary embolism shows a high mortality especially for the difficulty in establishing an early correct diagnosis. The pathophysiology and thus the clinical manifestations of pulmonary embolism (PE) are essentially conditioned by three factors: the size of the embolus, the pre-existing cardiorespiratory condition, the release caused by the embolus, of some substances or the activation of reflexes which tend to worsen the purely mechanical consequences of PE. The clinical manifestations resulting from the combination of these factors result in three clinical patterns: acute cor pulmonare, pulmonary infarction, acute dyspnea. PE symptoms may be absent in a moderate percentage of cases and if present, they are nonspecific. Some laboratory tests were shown to be of no diagnostic accuracy, as enzyme determination, a sign of necrosis, blood gas analysis, and determination of alveolar arterial oxygen gradient. Among blood coagulation tests, D-dimer determination was shown to be of some relevance. However, at present, it cannot be used to confirm the diagnostic suspicion of PE. Among the instrumental cardiologic procedures, while ECG has a poor diagnostic reliability, transesophageal echocardiography in central embolism may be able to visualize the embolus and to accurately assess the hemodynamic effects, supplying sufficient information for PE therapy. Even if imaging procedures as pulmonary angiography and more recently CT or MRI are the most reliable diagnostic tools, the diagnostic suspicion of PE in subjects at risk, the use of the examined methods and the search in these patients for the presence of lower limb deep vein thrombosis, often asymptomatic, may increase the number of treated patients thus decreasing the mortality of this disease.     

A lung ultrasound sign allowing bedside distinction between pulmonary edema and COPD: the comet-tail artifact

OBJECTIVE: Acute cardiogenic pulmonary edema and exacerbation of chronic obstructive pulmonary disease (COPD) can have a similar clinical presentation, and X-ray examination does not always solve the problem of differential diagnosis. The potential of lung ultrasound to distinguish these two disorders was assessed. DESIGN: Prospective clinical study. SETTING: The medical ICU of a university-affiliated teaching hospital. PATIENTS: We investigated 66 consecutive dyspneic patients: 40 with pulmonary edema and 26 with COPD. In addition, 80 patients without clinical and radiologic respiratory disorders were studied. MEASUREMENTS: The sign studied was the comet-tail artifact arising from the lung wall interface, multiple and bilaterally disseminated to the anterolateral chest wall. RESULTS: The feasibility was 100%. The length of the examination was always under 1 min. The described pattern was present in all 40 patients with pulmonary edema. It was absent in 24 of 26 cases of COPD as well as in 79 of 80 patients without respiratory disorders. The sign studied had a sensitivity of 100% and a specificity of 92% in the diagnosis of pulmonary edema when compared with COPD. CONCLUSIONS: With a described pattern present in 100% of the cases of pulmonary edema and absent in 92% of the cases of COPD and in 98.75% of the normal lungs, ultrasound detection of the comet-tail artifact arising from the lung-wall interface may help distinguish pulmonary edema from COPD.     

The traps of pulmonary embolism

The clinical diagnosis of pulmonary embolism (PE), even massive, remains difficult and perplexing. In our hospital, the percentage of exact clinical diagnoses has not significantly changed over recent years, with a false-negative rate of 78%, and a false-positive rate of 2%. In approximately 20% of cases, autopsy showed several emboli and pulmonary infarctions of various ages, indicating recurrent embolic episodes. The diseases most frequently associated were cardiac diseases (51%) and tumours (24%). Pneumonia considerably decreases the probability of an exact diagnosis of PE; hospitalisation in the Cardiology department or Intensive Care Unit increased the probability of this diagnosis. While the numerous diagnostic algorithms recently proposed have a limited value, the process integrating clinical and instrumental data in order to establish a prospective clinical probability, should facilitate identification of acute PE in live patients.     

Utility of an integrated clinical, echocardiographic, and venous ultrasonographic approach for triage of patients with suspected pulmonary embolism

The potential role of ultrasound techniques in diagnosing acute pulmonary embolism (PE) has been investigated in severe cases with hemodynamic compromise, but is still unclear for the whole clinical spectrum of patients with suspected PE. The aim of this study was to assess the utility of an integrated bedside evaluation for PE based on the combination of a clinical score, 2-dimensional echocardiography, and color venous duplex scanning. A group of 117 consecutive patients with suspected PE was assessed using a clinical likelihood score, echocardiography, and venous duplex scanning in order to obtain a preliminary diagnosis of PE, which was subsequently compared with the final diagnosis obtained by lung perfusion scintigraphy and angiography. A preliminary diagnosis of PE was made in 70 patients; a final diagnosis of PE was made in 63 patients, of which 56 had and 7 did not have a preliminary diagnosis of PE. The preliminary diagnosis therefore showed 89% sensitivity and 74% specificity, with a total accuracy of 82%. In patients with massive PE, sensitivity and negative predictive values of the preliminary diagnosis were 97% and 98%, respectively. Echocardiography was poorly sensitive (51%) but highly specific (87%) for PE. Thus, the integration of clinical likelihood, echocardiography, and venous duplex scanning provides a practical approach to patients with suspected PE, allows the rapid implementation of appropriate management strategies, and may reduce or postpone the need for further instrumental evaluation of more limited access.     

Sensitivity and specificity of a rapid whole-blood assay for D-dimer in the diagnosis of pulmonary embolism

BACKGROUND: Patients with suspected pulmonary embolism often have nondiagnostic lung scans and may present in circumstances where lung scanning is unavailable. Levels of D-dimer, a fibrin-specific product, are increased in patients with acute thrombosis; this may simplify the diagnosis of pulmonary embolism. OBJECTIVE: To determine the sensitivity and specificity of a whole-blood D-dimer assay in patients with suspected pulmonary embolism and in subgroups of patients with low pretest probability of pulmonary embolism or nondiagnostic lung scans. DESIGN: Prospective cohort. SETTING: Four tertiary care hospitals. PATIENTS: 1177 consecutive patients with suspected pulmonary embolism. MEASUREMENTS: All patients underwent an assessment of pretest probability by use of a standardized clinical model, a D-dimer assay, ventilation-perfusion lung scanning, and bilateral compression ultrasonography. Patients in whom pulmonary embolism was not initially diagnosed were followed for 3 months. Accordingly, patients were categorized as positive or negative for pulmonary embolism. RESULTS: Of the 1177 patients, 197 (17%) were classified as positive for pulmonary embolism. Overall, the D-dimer assay showed a sensitivity of 84.8% and a specificity of 68.4%. In 703 patients (3.4%) with a low pretest probability of pulmonary embolism, the likelihood ratio associated with a negative D-dimer test result was 0.27, resulting in a posterior probability of 1.0% (95% CI, 0.3% to 2.2%). In 698 patients with nondiagnostic lung scans (previous probability, 7.4%), the likelihood ratio associated with a negative D-dimer test result was 0.36, resulting in a posterior probability of 2.8% (CI, 1.4% to 4.8%). CONCLUSIONS: A normal D-dimer test result is useful in excluding pulmonary embolism in patients with a low pretest probability of pulmonary embolism or a nondiagnostic lung scan.     

Pulmonary embolism in patients with intermediate probability lung scans: diagnosis with Doppler venous US and D-dimer measurement

PURPOSE: To test the usefulness of lower limb Doppler venous compression ultrasound (US) and serum D-dimer measurements in diagnosis of pulmonary embolism in patients in whom ventilation-perfusion (V-P) scans indicate intermediate probability of pulmonary embolism. MATERIALS AND METHODS: V-P scanning, pulmonary angiography, US, and D-dimer measurements were performed in 36 patients without known deep venous thrombosis but with intermediate probability of having a pulmonary embolism. RESULTS: Pulmonary angiography demonstrated pulmonary embolism in 15 (41%) of 36 patients. US demonstrated deep venous thrombosis in only two patients, both with pulmonary embolism. Sensitivity of US was only 13%, but specificity was 100%. Five (14%) of the 36 patients had normal (< 220 micrograms/L) D-dimer levels; none of the five had pulmonary embolism. Sensitivity and specificity of D-dimer values were 100% and 16%, respectively, with a negative predictive value of 100%. CONCLUSION: Combined D-dimer measurement and US were helpful in correctly diagnosing pulmonary embolism in only seven (20%) of 36 patients. Pulmonary angiography is still required to diagnose pulmonary embolism in the majority of patients.     

The risk of a diagnosis of cancer after primary deep venous thrombosis or pulmonary embolism

BACKGROUND: Several small studies have indicated an association between deep venous thrombosis or pulmonary embolism and a subsequent diagnosis of cancer, but the subject is controversial. METHODS: We conducted a nationwide study of a cohort of patients with deep venous thrombosis or pulmonary embolism that was drawn from the Danish National Registry of Patients for the years 1977 through 1992. The occurrence of cancer in the cohort was determined by linkage to the Danish Cancer Registry. The expected number of cancer cases was estimated on the basis of national age-, sex-, and site-specific incidence rates. RESULTS: A total of 15,348 patients with deep venous thrombosis and 11,305 patients with pulmonary embolism were identified. We observed 1737 cases of cancer in the cohort with deep venous thrombosis, as compared with 1372 expected cases (standardized incidence ratio, 1.3; 95 percent confidence interval, 1.21 to 1.33). Among the patients with pulmonary embolism, the standardized incidence ratio was 1.3, with a 95 percent confidence interval of 1.22 to 1.41. The risk was substantially elevated only during the first six months of follow-up and declined rapidly thereafter to a constant level slightly above 1.0 one year after the thrombotic event. Forty percent of the patients given a diagnosis of cancer within one year after hospitalization for thromboembolism had distant metastases at the time of the diagnosis of cancer. There were strong associations with several cancers, most pronounced for those of the pancreas, ovary, liver (primary hepatic cancer), and brain. CONCLUSIONS: An aggressive search for a hidden cancer in a patient with a primary deep venous thrombosis or pulmonary embolism is not warranted.     

Bioethics: occupational therapy attitudes toward the prolongation of life

Two cases of massive pulmonary embolism, confirmed by angiographic or necropsy findings, were remarkable by the absence of arterial hypoxaemia. The various mechanisms responsible for arterial hypoxaemia in pulmonary embolism are discussed. It is suggested that in patients with massive pulmonary embolism a markedly decreased cardiac output might account for the absence of arterial hypoxaemia. In the light of these two cases the finding of a normal PaO2 does not rule out the diagnosis of pulmonary embolism.     

Study on antifertility effect of a novel LHRH antagonist in male rats

The diagnosis of pulmonary embolism is even in contemporary clinical practice problematical. Pulmonary angiography is used in our departments very little due to its invasive character. The method of choice for diagnosis remains therefore perfusion scintigraphy of the lungs, in this country frequently without ventilation scintigraphy as it is not available in the majority of our departments of nuclear medicine. In recent years in the diagnostic algorithms also assessment of D-dimers was started, i.e. assessment of products of fibrinolysis assessed by monoclonal antibodies. The authors tried to find out how many patients admitted to the medical department for diagnosis of pulmonary embolization may have a false positive diagnosis on the basis of pulmonary scintigraphy. During the period III/96 to V/96 a total of 18 patients from the medical clinic with suspected pulmonary embolism were examined where the value of D-dimers(latex test) was assessed and at the same time perfusion scintigraphy was performed. With regard to the highly negative predictive value of D-dimer assessment the authors focused their attention on patients with a suspect or positive lung scan (i.e. treated on account of pulmonary embolism) while D-dimers were negative. Of 13 patients with suspect or possible pulmonary embolism, as assessed by scintigraphy, four had negative dimers(30%). With regard to the 90% reported negative predictive value, based on the literature, thus three of these patients were unnecessarily admitted to hospital and treated. The authors assume that assessment of D-dimers should be part of the examination protocol due to its non-pretentious character and low price as compared with costs of hospitalization.     

Venous thromboses and pulmonary emboli in autopsy material (author's transl)

Venous thromboses of the pelvic veins and the veins of the lower limbs were found in 40% of the post mortems carried out on 1350 adults during 1974. The thromboses were bilaterally located in the calf veins in the vast majority of cases. The predominating underlying diseases of patients with thrombosis were malignant neoplasia or cardiovascular diseases. 319 cases (23.5%) showed massive pulmonary embolism. The pulmonary embolism had taken a fulminating fatal course in 7.8% of cases. Thromboses of the lower limb veins seem to have a higher tendency to become mobilized to cause fatal pulmonary embolism than thromboses occurring in other sites. A significantly higher incidence of venous thrombosis, as well as of pulmonary embolism, was found in higher age groups and in female patients; the prognosis is, moreover, grave in these cases. A significant increase in the incidence of venous thromboses and pulmonary embolism-especially those with a rapidly fatal course-has been registered over the past years as compared with previous investigations.     

Usefulness of computerized tomography in the study of pleural effusion with no presumed diagnosis

To establish the diagnostic yield of computerized tomography (CT) in pleural effusions with no presumed diagnosis arising from standard clinical examination. A prospective protocol study enrolling all cases of effusion admitted to our hospital between January 1994 through July 1995 without a presumed diagnosis after initial testing that included thoracocentesis. Twenty-two patients were enrolled. All were given a CT scan as well as other complementary examinations considered appropriate and were referred to our outpatient clinic for follow-up. The CT images were read by an expert radiologist and their contribution was classified as "diagnostic", "suggestive" or "nil". A definitive etiologic diagnosis was achieved in 14 cases (8 neoplasms, 4 benign due to asbestos, 1 tuberculosis and 1 pulmonary embolism). The CT contribution was nil in 13 cases (59%), "diagnostic" in 6 (2 mesotheliomas, 1 hypernephroma, 1 lymphoma, 1 adenocarcinoma of the colon and another of the ovary) and "suggestive" in 3 (2 benign due to asbestos and 1 lymphoma). Positive information was obtained in 9 cases (41%). CT gives good yield in the investigation of pleural effusions with no presumed diagnosis and should be made available to this group of patients before other more invasive procedures are resorted to. It is especially useful for detecting neoplastic disease of the upper abdomen, mesothelioma and sings of unsuspected exposure to asbestos.     

Effect of anatomic distribution of pulmonary emboli on interobserver agreement in the interpretation of pulmonary angiography

OBJECTIVE: This study examines the anatomic distribution of emboli on pulmonary angiography and attempts to determine the relationship of vessel size to interobserver agreement, two factors having important implications in comparing pulmonary angiography with cross-sectional imaging for pulmonary embolism. MATERIALS AND METHODS: One hundred twenty-five consecutive pulmonary angiograms were reviewed retrospectively by three interventional radiologists. Initial interpretations were recorded and compared to determine interobserver agreement on a per-patient and per-embolus basis. Discordant interpretations were reviewed by all radiologists for a consensus interpretation. RESULTS: Unanimous per-patient agreement occurred in 91% (114/125) of initial interpretations. The largest artery containing acute pulmonary embolism was segmental or larger in 24 patients (83% of patients with acute positive findings, 19% of all patients) and subsegmental in only five patients (17% and 4%, respectively). On a per-patient basis, initial interobserver agreement averaged 45% and unanimous consensus agreement was achieved for 79% of patients having isolated subsegmental pulmonary embolism. Consensus readings altered initial per-patient interpretations for 30% of patients having only subsegmental pulmonary embolism; per-embolus interpretations were altered for 37% of all subsegmental emboli. CONCLUSION: Subsegmental emboli occurring as isolated findings are relatively rare. Approximately one third of subsegmental emboli and one third of patients having isolated subsegmental emboli may be initially misdiagnosed on pulmonary angiography. Objections to cross-sectional imaging for pulmonary embolism based on the inability to detect subsegmental pulmonary embolism when compared with pulmonary angiography should be reexamined with this data in mind.     

Usefulness of argyrophilic nucleolar organizer regions score to differentiate suspicious malignancy in pulmonary cytology

OBJECTIVE: Pulmonary cytologic specimens reported as "suspicious for malignancy" pose problems in clinical management. Silver staining for argyrophilic nucleolar organizer regions (AgNOR) has proved useful in making a cytopathologically differential diagnosis between benign and malignant cells. This study aimed to evaluate the usefulness of AgNOR score in the diagnosis of pulmonary cytologic specimens deemed inconclusive by conventional staining methods. METHODS: Pulmonary cytologic specimens initially reported as suspicious for malignancy with Papanicolaou or May-Grünwald-Giemsa (MGG) staining obtained from 35 proved cases were destained then restained using the AgNOR technique. Another 35 cases with clear cytologic diagnosis were also examined for comparison. The median number of dots, defined as the AgNOR score, was used to differentiate malignant from benign specimens. RESULTS: Malignant cases had significantly higher AgNOR scores than benign ones (p<0.001). There were no significant differences among smears previously stained with Papanicolaou or MGG method, among specimens obtained via bronchoscopic brushing, fine-needle aspiration of lung or pleural effusion, or among subgroups of malignant diseases. Based on the results of our previous study, the cutoff value of the AgNOR score to differentiate benignancy from malignancy was set at 6. At this setting, the sensitivity and specificity of AgNOR score were 88% and 80%, respectively, in aiding a differential diagnosis of pulmonary cytologic specimens initially classified as suspicious for malignancy. For those cases with a clear cytologic diagnosis, the sensitivity and specificity of AgNOR score were 92% and 100%, respectively. For all cases, the sensitivity of AgNOR score was 90% and the specificity was also 90%. CONCLUSIONS: The AgNOR score is of value in aiding a differential diagnosis between benign and malignant lesions in pulmonary specimens with equivocal cytologic features.     

The role of venous ultrasonography in the diagnosis of suspected deep venous thrombosis and pulmonary embolism

This paper describes the role of venous ultrasonography in the diagnosis of suspected deep venous thrombosis and pulmonary embolism. Inability to compress the common femoral or popliteal vein is usually diagnostic of a first episode of deep venous thrombosis in symptomatic patients (positive predictive value of about 97%). Full compressibility of both of these sites excludes proximal deep venous thrombosis in symptomatic patients (negative predictive value of about 98%). In patients with suspected deep venous thrombosis or in those who present with suspected pulmonary embolism but have a nondiagnostic lung scan, the subsequent risk for symptomatic venous thromboembolism is very low (<2% during 6 months of follow-up) provided that ultrasonography of the proximal veins remains normal in the course of 1 week (suspected deep venous thrombosis) or 2 weeks (suspected pulmonary embolism). Anticoagulation and further diagnostic testing can usually be safely withheld in these situations. Venous ultrasonography is much less reliable for the diagnosis of asymptomatic, isolated distal, and recurrent deep venous thrombosis than for the diagnosis of a first episode of proximal deep venous thrombosis in symptomatic patients. Clinical evaluation of the probability of deep venous thrombosis or pulmonary embolism, preferably by using a validated clinical model, complements venous ultrasonographic findings and helps to identify patients who would benefit from additional (often invasive) diagnostic testing. Thus, venous ultrasonography is thought to be a very valuable test for the diagnosis and management of patients with suspected deep venous thrombosis or pulmonary embolism.     

Diagnosis and treatment of shock due to massive pulmonary embolism: approach with transesophageal echocardiography and intrapulmonary thrombolysis

STUDY OBJECTIVES: To evaluate the diagnostic value of transesophageal echocardiography (TEE) as an initial diagnostic tool in shocked patients. The second objective was to study therapeutic impact of intrapulmonary thrombolysis in patients with diagnosed massive pulmonary embolism. DESIGN: Prospective observational study. SETTING: Medical ICU in 800-bed general hospital. PATIENTS: Twenty-four consecutive patients with unexplained shock and distended jugular veins. MEASUREMENTS AND MAIN RESULTS: In 18 patients, right ventricular dilatation with global or segmental hypokinesis was documented. In addition, central pulmonary thromboemboli (12 patients), reduced contrast flow in right pulmonary artery (one patient), and right ventricular free wall akinesis (one patient) were found. No additional echocardiographic findings were apparent in four patients. According to pulmonary scintigraphy or autopsy, sensitivity of TEE for diagnosis of massive pulmonary embolism (MPE) in patients with right ventricular dilatation was 92% and specificity was 100%. In patients without right ventricular dilatation, left ventricular dysfunction (four patients) or cardiac tamponade (two patients) was confirmed. Intrapulmonary thrombolysis was evaluated in 11 of 13 patients with MPE. Two patients died prior to attempted thrombolysis. Three patients received streptokinase and eight received urokinase. Twenty-four hours after beginning of treatment, total pulmonary resistance index significantly decreased for 59% and mean pulmonary artery pressure for 31%. Cardiac index increased for 74%. Nine of 11 patients receiving thrombolysis survived to hospital discharge. CONCLUSION: Bedside TEE is a valuable tool for diagnosis of MPE. It enables immediate intrapulmonary thrombolysis, which seems to be an effective therapeutic alternative in our group of patients with obstructive shock.     

Pulmonary embolism: prospective comparison of spiral CT with ventilation-perfusion scintigraphy

PURPOSE: To compare prospectively the accuracy of spiral computed tomography (CT) with that of ventilation-perfusion scintigraphy for diagnosing pulmonary embolism. MATERIALS AND METHODS: Within 48 hours of presentation, 142 patients suspected of having pulmonary embolism underwent spiral CT, scintigraphy, and (when indicated) pulmonary angiography. Pulmonary angiography was attempted if interpretations of spiral CT scans and of scintigrams were discordant or indeterminate and intermediate-probability, respectively. RESULTS: In the 139 patients who completed the study, interpretations of spiral CT scans and of scintigrams were concordant in 103 patients (29 with embolism, 74 without). In 20 patients, intermediate-probability scintigrams were interpreted (six with embolism at angiography, 14 without); diagnosis with spiral CT was correct in 16. Interpretations of spiral CT scans and those of scintigrams were discordant in 12 cases; diagnosis with spiral CT was correct in 11 cases and that with scintigraphy was correct in one. Spiral CT and scintigraphic scans of four patients with embolism did not show embolism. Sensitivities, specificities, and kappa values with spiral CT and scintigraphy were 87%, 95%, and 0.85 and 65%, 94%, and 0.61, respectively. CONCLUSION: In cases of pulmonary embolism, sensitivity of spiral CT is greater than that of scintigraphy. Interobserver agreement is better with spiral CT.