Diagnosis of pulmonary embolism with magnetic resonance angiography

BACKGROUND: Diagnosing pulmonary embolism may be difficult, because there is no reliable noninvasive imaging method. We compared a new noninvasive method, gadolinium-enhanced pulmonary magnetic resonance angiography, with standard pulmonary angiography for diagnosing pulmonary embolism. METHODS: A total of 30 consecutive patients with suspected pulmonary embolism underwent both standard pulmonary angiography and magnetic resonance angiography during the pulmonary arterial phase at the time of an intravenous bolus of gadolinium. All magnetic resonance images were reviewed for the presence or absence of pulmonary emboli by three independent reviewers who were unaware of the findings on standard angiograms. RESULTS: Pulmonary embolism was detected by standard pulmonary angiography in 8 of the 30 patients in whom pulmonary embolism was suspected. All 5 lobar emboli and 16 of 17 segmental emboli identified on standard angiograms were also identified on magnetic resonance images. Two of the three reviewers reported one false positive magnetic resonance angiogram each. As compared with standard pulmonary angiography, the three sets of readings had sensitivities of 100, 87, and 75 percent and specificities of 95, 100, and 95 percent, respectively. The interobserver correlation was good (k=0.57 to 0.83 for all vessels, 0.49 to 1.0 for main and lobar vessels, and 0.40 to 0.81 for segmental vessels). CONCLUSIONS: In this preliminary study, gadolinium-enhanced magnetic resonance angiography of the pulmonary arteries, as compared with conventional pulmonary angiography, had high sensitivity and specificity for the diagnosis of pulmonary embolism. This new technique shows promise as a noninvasive method of diagnosing pulmonary embolism without the need for ionizing radiation or iodinated contrast material.     

Prevalence of acute pulmonary embolism in central and subsegmental pulmonary arteries and relation to probability interpretation of ventilation/perfusion lung scans

PURPOSE: The purpose of this investigation is to determine the prevalence of acute pulmonary embolism (PE) limited to subsegmental pulmonary arteries. BACKGROUND: Contrast-enhanced helical (spiral) and electron-beam CT, in the hands of experienced radiologists who are skillful with this modality, are sensitive for the detection of acute PE in central pulmonary arteries, but have a low sensitivity for the detection of PE limited to subsegmental pulmonary arteries. The potential for CT to diagnose PE, therefore, is partially dependent on the prevalence of PE limited to subsegmental pulmonary arteries. METHODS: Data are from the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED). The largest pulmonary arteries that showed PE, as interpreted by the PIOPED angiographic readers, were identified in 375 patients in PIOPED with angiographically diagnosed PE. RESULTS: Among all patients with PE, 6% (95% confidence interval [CI], 4 to 9%) had PE limited to subsegmental branches of the pulmonary artery. Patients with high-probability ventilation/ perfusion (V/Q) scans had PE limited to subsegmental branches in only 1% (95% CI, 0 to 4%). Among patients with low-probability V/Q lung scans, 17% (95% CI, 8 to 29%) had PE limited to the subsegmental branches. Patients with low-probability V/Q scans and no prior cardiopulmonary disease had PE limited to the subsegmental pulmonary arteries in 30% (95% CI, 13 to 53%), whereas patients with low-probability V/Q scans who had prior cardiopulmonary disease had PE limited to subsegmental pulmonary arteries in 8% (95% CI, 2 to 22%) (p < 0.05). CONCLUSION: Based on data from all patients with PE in PIOPED, the prevalence of PE limited to subsegmental pulmonary arteries is low, 6%. PE limited to subsegmental pulmonary arteries was most prevalent among patients with low-probability V/Q scans, particularly if they had no prior cardiopulmonary disease.     

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.     

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.     

Diagnosis of pulmonary embolism with spiral and electron-beam CT

PURPOSE: To compare spiral (SCT) and electron-beam CT (EBT) for the diagnosis of pulmonary embolism (PE). MATERIALS AND METHODS: From June 1997 to June 1998 188 patients with suspected acute or chronic thromboembolism of the pulmonary arteries were examined. A total of 108 patients were scanned using SCT and 80 patients using EBT. On each scanner two different scan protocols were evaluated. RESULTS: PE was diagnosed in 38 patients using EBT and in 49 patients using SCT. Especially with EBT, isolated peripheral emboli could be confidently diagnosed. When EBT and SCT were compared for the analysis of peripheral pulmonary arteries, some paracardiac segmental and subsegmental vessels were significantly better analyzable with EB. Additional or diseases other than PE were diagnosed in 112 patients. Other diagnoses included bronchial carcinoma and aortic dissection. CONCLUSIONS: Advanced CT scanning techniques allow the highly accurate diagnosis of central and peripheral PE. Other potentially life-threatening underlying diseases are also readily recognized.     

Magnetic resonance pulmonary angiography and direct imaging of embolus for the detection of pulmonary emboli

RATIONALE AND OBJECTIVES: The authors developed a two-dimensional breathhold magnetic resonance (MR) technique for the direct imaging of pulmonary emboli. METHODS: In vitro MR imaging was performed to demonstrate the potential generation of clot-blood contrast by in vivo pulmonary embolism (PE). A two-dimensional magnetization prepared gradient-echo (turbo-FLASH) breathhold technique was designed to directly image intravascular emboli by the selective nulling of the blood signal. A turbo-FLASH pulmonary angiographic breathhold sequence was used to provide spatial localization of detected emboli. Thirteen patients with suspected PE were studied; 6 patients underwent conventional pulmonary angiography (CPA) and the remaining 7 had diagnoses based on findings from other studies. RESULTS: In vitro study of blood clot demonstrated an initial rise and then fall in T1 sufficient to generate clot-blood contrast after eight days of clot formation. All patients with CPA or alternative study evidence of PE were diagnosed as positive with direct embolus imaging MR. There were no false-positive diagnoses. Three additional emboli were detected using the MR technique compared with CPA. The MR pulmonary angiographic sequence provided a useful road map for localization of intravascular emboli but was less sensitive for PE detection than the embolus imaging technique. CONCLUSIONS: The direct imaging of PE is feasible using a simple two-dimensional breathhold technique.     

Spiral CT angiography in the diagnosis of central pulmonary embolism: comparison with pulmonary angiography and scintigraphy

PURPOSE: To evaluate the accuracy of spiral CT angiography in the diagnosis of central pulmonary embolism (PE). MATERIAL AND METHODS: A retrospective study was undertaken in a population of 90 patients who were evaluated with spiral CT angiography (acquisition: 12 to 24 s with or without strict apnea; injection of 90 cm3 of 12, 20 or 30% contrast material at a rate of 4 to 7 cm3, selective pulmonary angiography of each lung (n = 55) and/or ventilation-perfusion (VP) scanning (n = 35). RESULTS: Among the 55 patients evaluated with both spiral CT and angiography, central pulmonary embolism was excluded in 19 patients (34%), assessed in 29 patients (53%) whereas CT examination was considered as inconclusive in 7 patients (13%) due to interpretive difficulties at the level of obliquely oriented arteries and/or presence of hilar lymph nodes (sensitivity: 90.5%; specificity: 82.6%). With spiral CT, the finding of 95 central emboli (3 main, 61 lobar and 31 segmental) corresponded exactly to the angiographic findings; spiral CT enabled direct visualization of intraluminal filling defects (n = 95) whereas the angiographic recognition of PE was based on direct (n = 57) and indirect (n = 38) signs. Spiral CT angiography was more sensitive and specific than VP scanning. CONCLUSION: Spiral CT angiography appears as a sensitive and specific noninvasive method for the diagnosis of central PE.     

A comparative analysis of pulmonary perfusion scans with pulmonary angiograms

Pulmonary angiograms and pulmonary lung perfusion scans on 162 patients with pulmonary embolism were comparatively analyzed. Among the expert angiographic panel members who independently evaluated the studies there was consistent agreement on the diagnosis, size of the emboli, and severity. Consistency of agreement among the expert pulmonary lung perfusion scan panelists was considerably less. These data demonstrate that, in addition to the lack of specificity of the lung perfusion scan for the diagnosis of pulmonary thromboemboli, there is a considerable problem of interpretation in this patient population.     

Unsuspected pulmonary embolism: prospective detection on routine helical CT scans

PURPOSE: To determine the prevalence of unsuspected pulmonary embolism (PE) on routine thoracic helical computed tomographic (CT) scans and to quantify the improvement in PE detection by using a cine-paging mode on a workstation instead of hard-copy review. MATERIALS AND METHODS: Seven hundred eighty-five patients referred for routine contrast medium-enhanced thoracic CT within 9 months were prospectively recruited. Helical CT was performed. Studies were prospectively interpreted by four radiologists. Two radiologists performed routine, undirected, hard-copy consensus review for official interpretation; two of three thoracic radiologists independently performed a dedicated workstation-based search for PE. The presence of PE involving the main, lobar, or segmental pulmonary arteries was assigned a score of 1-5 (1 = definitely negative, 5 = definitely positive) by each independent reviewer. Patients with a score of 4 or 5 underwent lower-extremity ultrasound, ventilation-perfusion scintigraphy, or both, followed by pulmonary CT angiography if the findings were still equivocal. RESULTS: Twelve (1.5%) of the 785 patients had unsuspected PE, with an inpatient prevalence of 5% (eight of 160) and an outpatient prevalence of 0.6% (four of 625). Of the 12 patients with unsuspected PE, 10 (83%) had cancer. Of the 81 inpatients with cancer, seven (9%) had unsuspected PE. A dedicated workstation-based search resulted in detection of PE in three more patients (25%) than did hard-copy interpretation. CONCLUSION: The prevalence of unsuspected PE was highest among inpatients with cancer. A directed, workstation-based search can improve the PE detection rate over that with hard-copy review.     

Consequences of a small decrease of air temperature from thermal equilibrium on thermoregulation in sleeping neonates

PURPOSE: To evaluate macromolecular contrast-enhanced MR-angiography for the detection of experimentally induced pulmonary artery embolism and to determine the size of the smallest detectable embolised vessel. METHODS: Pulmonary artery embolism was artificially induced in eight isolated perfused sheep lungs by injecting room air into the main pulmonary artery. The pulmonary vascular system enhanced by macromolecular gadolinium-DTPA-polylysine was imaged with a flow-sensitive gradient-echo technique. RESULTS: Pulmonary artery embolism was demonstrated in all eight lungs by an obvious cut-off phenomenon in the contrast-enhanced arteries proximal to the pulmonary air emboli. The smallest detectable embolised artery measured 1.6 mm in diameter and was located in the 6th generation of the pulmonary vascular system. CONCLUSIONS: In this experimental study MR angiography enhanced by a macromolecular contrast agent allowed noninvasive diagnosis of pulmonary artery embolism.     

Time-of-flight MR arteriography of below-knee arteries with maximum-intensity-projection reconstruction: is interpretation of the axial source images helpful?

OBJECTIVE: We evaluated the extent to which detailed review of axial source images enhances the interpretation of projectional reconstructions of two-dimensional time-of-flight MR arteriograms of the tibial vessels. SUBJECTS AND METHODS: Thirty-one patients (34 limbs) with limb-threatening ischemia underwent two-dimensional time-of-flight imaging and contrast-enhanced angiography of the below-knee arteries. Maximum-intensity-projection (MIP) reconstructions of the MR arteriograms were independently interpreted by three observers. The studies were then reinterpreted after detailed review of the axial source images. A consensus reading of each study was performed as well. The observers commented on the patency of 816 vascular segments and graded the extent of disease for 272 vessels. Interobserver agreement and correlation with contrast-enhanced angiography were determined. RESULTS: On average, the addition of axial images altered the observers' interpretation of MR arteriograms in 13% of segments for patency and in 18% of vessels for grading of disease severity. For determining the patency of vascular segments, mean interobserver agreement was 0.79 without and 0.80 with axial image interpretation, and mean agreement with contrast-enhanced angiography improved from 0.69 to 0.72 with the addition of axial images. When evaluating the extent of disease, correlation between observers improved for all combinations of observers with the addition of axial images, and correlation with contrast-enhanced angiography improved for two of three observers. Based on the consensus interpretation of the MR arteriograms, review of axial images was found to improve agreement with contrast-enhanced angiography in 34 vascular segments. In addition, axial image review correctly altered the number of stenoses identified in 12 vessels. When consensus interpretation identified a vessel as patent without significant stenosis on the MIP images, the MIP-based interpretation was found to be correct in all cases. CONCLUSION: Review of axial source images provides limited benefit to interpretation of MR arteriograms of the distal lower extremity in patients with peripheral vascular disease. Although selective review of axial source images may be appropriate, axial images can improve interpretation when MIP images are complicated by the presence of patient motion, difficult anatomy, or artifacts. Axial image review may also be appropriate when a significant stenosis is identified on the MIP images.     

Scintigraphy with 111In-labeled autologous platelets in venous thromboembolism

Scintigraphy with 111in-labeled autologous platelets was performed in 20 patients with suspected venous thrombosis and/or pulmonary embolism. The platelets accumulated in venous thrombi in 6 or 7 patients (86%) with positive findings on impedance plethysmography or contrast venography; all 6 were receiving intravenous heparin. In 11 patients with pulmonary embolism diagnosed by ventilation--perfusion imaging or pulmonary angiography, platelet scintigraphy showed embolic uptake only in the one patient not on full-dose heparin. These findings suggest that scintigraphy with 111In-platelets is a promising noninvasive technique for detection of deep venous thrombosis. Heparin does not appear to block localization of labeled platelets in venous thrombi, but may inhibit their adherence to pulmonary emboli.     

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.     

Interobserver variability in the interpretation of chest roentgenograms of patients with possible pneumonia

BACKGROUND: Previous studies have found considerable interobserver variability in the roentgenographic diagnosis of pneumonia. In this study we determined the impact of experience on interobserver variability in the interpretation of chest roentgenograms of patients with pneumonia and defined the characteristics of chest roentgenograms interpreted as pneumonia by all groups. METHODS: The chest roentgenograms of 15 consecutive patients with a clinical and roentgenographic diagnosis of pneumonia were read by a convenience sample of 10 first-year and 20 fourth-year medical students, 21 medical residents, and 21 staff physicians from the department of medicine. Three board-certified radiologists served as the gold standard. The majority rule decision and logistic regression analysis were used to analyze agreement among the various groups of observers. RESULTS: Agreement with the majority decisions of the gold-standard radiologists on the presence or absence of pneumonia for all observations of the various groups were as follows: original radiologist, 87%; first-year medical students, 59%; fourth-year medical students, 54%; medical residents, 66%; and attending staff, 72%. Chest roentgenograms with dense lobar or segmental opacities were generally interpreted as pneumonia by all observers. Patchy opacities caused major disagreements and were usually read as not being due to pneumonia. Bronchopneumonia was not diagnosed by any of the observers. Air bronchograms, atelectasis, and chronic obstructive lung disease were usually not recognized by the nonradiologists. CONCLUSIONS: There is considerable interobserver variability in the roentgenographic diagnosis of pneumonia. This variability does not improve with increasing experience. Dense lobar or segmental opacities are uniformly recognized as pneumonia while patchy opacities result in a variety of interpretations.     

Sonographic observation of pulmonary infarction and early infarctions by pulmonary embolism

Fifty-eight consecutive patients with clinical symptoms of pulmonary embolism/infarction were examined by ultrasound as the first imaging modality. The diagnosis was confirmed in 35 patients by ventilation-perfusion scintigraphy; 13 underwent pulmonary angiography for verification of clinical diagnosis. Seven patients died, necropsy was performed and the diagnosis of pulmonary embolism was confirmed in six cases; three patients were submitted to transthoracic lung biopsy. Intercostal space and an additional small pleural effusion in 48% of the examined patients served as a sonic window for the 5 MHz sector scanner. In 42 of the 54 cases with a final diagnosis of pulmonary embolism/infarction a total of 69, hypoechoic, lesions with a pleural basis were detected. These were conspicuous, predominantly triangular, of a mean size 4.6 x 3.7 cm (range 9 x 8 to 2 x 1.5). A hyperechoic structure with reverberation artefacts suggestive of air was frequently visible in the centre: a sign of segmental involvement. The ultrasound examination yielded a true positive result in 41 cases. The overall sensitivity was 98% and the specificity 66%. The prevalence of pulmonary embolism was 83% and the diagnostic accuracy 90%. This suggests that chest sonography can be an efficient technique in the detection of pulmonary infarction.     

Angiographic evaluation of chronic pulmonary embolism

In some patients acute pulmonary emboli may fail to resolve normally, resulting in chronic pulmonary embolism. This may lead to pulmonary hypertension, respiratory insufficiency, cor pulmonale, and death. The angiographic evaluation in nine patients with chronic pulmonary embolism who underwent embolectomy is presented. Particular emphasis on the predictive value of selective bronchial arteriography in four of these patients is considered. In chronic pulmonary embolism, pulmonary arteries distal to obstructed areas may remain patent and be supplied by hypertrophied bronchial arteries. Since back-bleeding of arterial blood from the bronchial circulation at surgery may predict the success of embolectomy, preoperative bronchial arteriography may be useful for predicting potential surgical success.     

Diagnostic value of echocardiography and thoracic spiral CT angiography in the diagnosis of acute pulmonary embolism

The objective of this study was to define the limits of echocardiography and to evaluate thoracic spiral CT angiography (TSCTA) for the diagnosis of pulmonary embolism (PE). One hundred twelve consecutive patients, hospitalised for suspected PE, were included in this prospective study. All were investigated by pulmonary ventilation-perfusion scintigraphy (Sc) and 50 had a high probability of PE on this examination. Sc was normal in 22 patients. Forty patients were excluded because of an intermediate probability. In 50 patients with PE confirmed on Sc, transthoracic echocardiography (TTE) showed only indirect evidence of PE (intracavitary thrombus in 4% of cases). TSCTA demonstrated PE in 82% of cases and did not show any thrombus image when Sc was normal. Its negative predictive value was therefore 70% and its positive predictive value was 100%. Its sensitivity varied according to degree of perfusion defect (96% in the case of lobar lesion, 66% in the case of segmental lesion and 16% for a subsegmental lesion). Multidimensional transoesophageal echocardiography (TOE), performed in 37 of the 50 patients with PE, only revealed thrombi in the pulmonary tree in 3 patients (8%), all presenting severe PE. No thrombus was visualized on TOE in patients with non-serious PE. All thrombi observed on TOE were also demonstrated by TSCTA. In conclusion, TTE usually provides only indirect signs of PE. TOE has a poor diagnostic sensitivity for PE. TSCTA has a better sensitivity than TOE for the detection of thrombi in the pulmonary artery trunk and proximal centimetres of its two branches, but normal CT angiography cannot exclude a distal PE.     

Pulmonary intravascular tumor emboli: dilated and beaded peripheral pulmonary arteries at CT

The diagnosis of pulmonary intravascular tumor emboli is difficult to establish both clinically and on conventional radiographic studies. Between 1985 and 1991, four cases of pulmonary intravascular metastases were demonstrated on computed tomographic (CT) scans from among 14,000 CT scans of the chest. A retrospective study of these cases was performed, including a review of chest radiographs. All four patients had invasive tumors, including an atrial myxoma, a renal cell carcinoma, an osteosarcoma, and a chondrosarcoma of the pelvis. Three cases had histopathologic documentation of pulmonary artery tumor emboli. At CT, all the patients demonstrated multifocal dilatation and beading of peripheral pulmonary arteries, primarily in a subsegmental distribution involving multiple lobes. Ossification of the pulmonary arteries occurred in one case of metastatic osteosarcoma. In two cases, small, peripheral wedge-shaped opacities distal to some abnormal pulmonary arteries suggested pulmonary infarcts. The finding of dilated and beaded peripheral pulmonary arteries at CT is highly suggestive of metastatic intravascular tumor emboli.     

Massive tumorous pulmonary embolism in hepatocarcinoma

Tumoral pulmonary embolism is among the causes of acute dyspnea in patients with neoplasia. This phenomenon, different to thrombotic embolism, occurs frequently in patients with lung, gastrointestinal, liver, breast and uterus neoplasia. It is usually asymptomatic and usually constitutes an autopsy finding in these patients. More rarely it manifests as a cor pulmonale which evolves subacutely. Exceptionally large tumoral emboli spread from a primary tumoral mass, and obstruct main pulmonary arterial vessels, causing a clinical picture indistinguishable from massive pulmonary thromboembolism. We present case of massive tumoral pulmonary embolism by an hepatocarcinoma. In spite of an early thrombolytic treatment the patient died from acute pulmonary hypertension.     

Experimentally induced nasal hypersecretion does not reduce the efficacy of intranasal levocabastine

Pulmonary tumor embolism is an often missed antemortem diagnosis in patients with cancer and respiratory failure. Although rare, this complication is an important cause of additional morbidity. Referred for radionuclide pulmonary perfusion and ventilation scintigraphy, a typical pattern of multiple subsegmental peripheral defects on perfusion lung scanning without matching ventilation defects, suggesting a high probability of pulmonary thromboembolism, often leads to false conclusions. We present a case of bilateral multiple subsegmental mismatched defects in lung ventilation perfusion scintigraphy, where autopsy confirmed the diagnosis of pulmonary tumor embolism, secondary to an undifferentiated ductal type adenocarcinoma of the pancreas. Pulmonary tumor embolism is an entity to keep in mind in patients treated for carcinoma presenting with (sub) acute dyspnea.