Reassessment of pulmonary angiography for the diagnosis of pulmonary embolism: relation of interpreter agreement to the order of the involved pulmonary arterial branch

PURPOSE: To reassess the validity of conventional pulmonary angiography in the diagnosis of pulmonary embolism (PE) in main, lobar, segmental, and subsegmental pulmonary arteries. MATERIALS AND METHODS: Data are from examinations of 375 patients with angiographically diagnosed PE who participated in the Prospective Investigation of Pulmonary Embolism Diagnosis. The average co-positivity of readings of the pulmonary angiograms was evaluated in relation to the order of the largest pulmonary artery that showed PE. RESULTS: Among 217 patients whose angiograms showed PE in main or lobar pulmonary arteries, as well as in smaller orders of arteries, there was an average co-positivity of 98% (95% Cl = 96%, 98%). Among 136 patients whose pulmonary angiograms showed PE in segmental or subsegmental pulmonary arteries but not in larger orders of arteries, the average co-positivity was 90% (95% Cl = 85%, 95%). Among 22 patients with PE limited to the subsegmental arteries, the average co-positivity was 66% (95% Cl = 46%, 86%). CONCLUSION: Conventional pulmonary angiography is not precise for the diagnosis of PE limited to subsegmental arteries. To evaluate subsegmental arteries, techniques that improve the visualization of PE in small arteries should be used.     

Systemic collateral supply in patients with chronic thromboembolic and primary pulmonary hypertension: assessment with multi-detector row helical CT angiography

PURPOSE: To compare retrospectively the frequency of systemic collateral supply in patients who have chronic thromboembolic pulmonary hypertension with the frequency of systemic collateral supply in patients who have primary pulmonary hypertension by using multi-detector row helical computed tomographic (CT) angiography. MATERIALS AND METHODS: For this review, neither institutional board approval nor informed consent was required. Thirty-six consecutive patients, including 22 patients (four men, 18 women; mean age, 46.0 years) with chronic thromboembolic pulmonary hypertension (group 1) and 14 patients (five men, nine women; mean age, 63.0 years) with primary pulmonary hypertension (group 2), underwent multisection spiral CT angiography of the pulmonary and systemic circulations with a four- (n = 17) or 16- (n = 19) detector row scanner. CT angiograms were assessed for the presence of abnormal bronchial and/or nonbronchial systemic arteries, CT features of pulmonary hypertension, and right ventricular dysfunction. Vascular and parenchymal signs of chronic pulmonary embolism were specifically analyzed on CT angiograms of group 1 patients. Comparative analyses were performed by using the chi(2) or the Fisher exact test for categoric data. An unpaired bilateral Wilcoxon rank sum test was used for continuous data. A chi(2) goodness-of-fit test was used to compare observed proportions with equal proportions. RESULTS: The degree of pulmonary hypertension was comparable in groups 1 and 2. Abnormally enlarged systemic arteries were identified in 16 (73%) of 22 patients from group 1 and in two (14%) of 14 patients from group 2 (P = .002). The systemic collateral supply in group 1 comprised enlargement of both bronchial and nonbronchial systemic arteries in nine (56%) of the 16 patients; the remaining seven patients had an exclusive enlargement of bronchial systemic arteries (n = 6, 38%) or nonbronchial (n = 1, 6%) systemic arteries. A total of 31 enlarged nonbronchial systemic arteries were depicted, including 13 inferior phrenic arteries, 10 intercostal arteries, seven internal mammary arteries, and one lateral thoracic artery. The mean +/- standard deviation of abnormal nonbronchial systemic arteries per patient was 1.4 +/- 1.9. No relationship was found between the mean number of abnormally enlarged nonbronchial systemic arteries and the CT angiographic features of chronic pulmonary embolism. CONCLUSION: These results demonstrate the higher frequency of abnormally enlarged bronchial and nonbronchial systemic arteries in patients who have chronic thromboembolic pulmonary hypertension compared with patients who have primary pulmonary hypertension; this finding could help distinguish these two entities on CT angiograms.     

Detection of central pulmonary embolism on computed tomography densitometry images before computed tomography pulmonary angiography

OBJECTIVE: The purpose of this article is to describe the imaging findings of acute central pulmonary embolism on computed tomography (CT) densitometry images performed before contrast-enhanced CT pulmonary angiography. METHODS: A retrospective review was conducted of reports from all CT pulmonary angiograms performed at our institution, and cases of acute central pulmonary embolism, defined as those with clot in the main, left, or right pulmonary arteries, were identified. Images of positive studies were reviewed on a picture archiving and communications system (PACS) workstation. RESULTS: A total of 1282 CT pulmonary angiograms were obtained for evaluation of possible acute pulmonary embolism, and 1 combined CT aortogram and pulmonary angiogram was performed for aortic dissection and acute pulmonary embolism. Two hundred fourteen (16.7%) examinations positive for acute pulmonary embolism were identified, 26 (12.1%, 2.0% of total examinations) of which had central clots. Of the 26 patients with central acute pulmonary embolism, 12 (46.1%, 5.6% of all positive studies and 0.9% of all CT pulmonary angiograms) had clots that were visible on the densitometry images. CONCLUSION: Although an uncommon finding, acute central pulmonary embolism can be detected on CT densitometry performed to optimize opacification of the pulmonary arteries for CT pulmonary angiography and may prove useful in selected clinical situations.     

Peripheral pulmonary artery pseudoaneurysms and massive hemoptysis

OBJECTIVE: The aim of this study was to determine the incidence and etiology of pulmonary artery pseudoaneurysms in patients undergoing bronchial angiography for massive hemoptysis and to assess patient outcome after the embolization of these pseudoaneurysms. CONCLUSION: Peripheral pulmonary artery pseudoaneurysms occur in up to 11% of patients undergoing bronchial angiography for hemoptysis. These are often most easily appreciated on bronchial and/or nonbronchial systemic arterial angiograms because of complete reversal of flow in pulmonary artery branches in the diseased lung. Embolization of bronchial and nonbronchial systemic arteries alone may not be sufficient therapy to control hemoptysis, and occlusion of the pseudoaneurysm itself via a pulmonary artery approach is recommended.     

Bronchial artery dilatation on MDCT scans of patients with acute pulmonary embolism: comparison with chronic or recurrent pulmonary embolism

OBJECTIVE: The purpose of our study was to compare the bronchial arteries of patients with acute pulmonary embolism with those of patients with chronic or recurrent pulmonary embolism. MATERIALS AND METHODS: Twenty-seven patients with acute pulmonary embolism and 14 patients with chronic or recurrent pulmonary embolism were retrospectively identified from 700 consecutive patients with suspected pulmonary embolism. The case data for the patients were assessed by two thoracic radiologists whose final judgments were reached by consensus. On the MDCT pulmonary angiograms obtained in these patients, the bronchial arteries were assessed by finding enhancing, small, round or curvilinear structures within the mediastinum and tracing their paths along the bilateral main bronchi. Bronchial arteries with a diameter greater than 1.5 mm were considered to be dilated. RESULTS: The diameters of the bronchial arteries in the group with chronic or recurrent pulmonary embolism were significantly larger than diameters of the bronchial arteries in the group with acute pulmonary embolism (p = 0.0002). Dilatation of bronchial arteries was observed in two of the 27 patients with acute pulmonary embolism and in seven of 14 patients with chronic or recurrent pulmonary embolism. This difference was statistically significant (p = 0.004). No dilated bronchial arteries were seen in patients who had acute pulmonary embolism but had no a history of deep venous thrombosis. CONCLUSION: Acute pulmonary embolism did not appear to cause dilatation of bronchial arteries, whereas chronic or recurrent pulmonary embolism was frequently associated with dilated bronchial arteries. In patients in whom the distinction between acute and chronic or recurrent pulmonary embolism on MDCT pulmonary angiography is clinically unclear and in whom the bronchial arteries are dilated, a diagnosis of chronic or recurrent pulmonary embolism should be favored.     

Peripheral pulmonary arteries: how far in the lung does multi-detector row spiral CT allow analysis?

PURPOSE: To analyze the influence of multi-detector row spiral computed tomography (CT) on identification of peripheral pulmonary arteries. MATERIALS AND METHODS: Peripheral pulmonary arteries were analyzed on optimally opacified contrast material-enhanced spiral CT angiograms in 30 patients devoid of pleuroparenchymal disease who underwent scanning with multi-detector row CT (collimation, 4 x 1 mm; pitch, 1.7-2.0; scanning time, 0.5 second). Two series of scans were systematically generated from each data set, 1.25-mm-thick (group 1) and 3-mm-thick (group 2) sections, leading to the analysis of 600 segmental (20 arteries per patient), 1,200 subsegmental (40 arteries per patient), 2,400 fifth-order (80 arteries per patient), and 4,800 sixth-order (160 arteries per patient) pulmonary arteries in each group. RESULTS: Multi-detector row CT with reconstructed scans of 1.25-mm-thick sections (group 1) allowed (a) analysis of a significantly higher percentage of subsegmental arteries (94% in group 1 vs 82% in group 2; P <.001) and (b) a significantly higher percentage of fifth- and sixth-order arteries, respectively, identified in 74% and 35% of cases in group 1 and 47% and 16% in group 2 (P <.001). The causes for inadequate depiction of subsegmental branches in group 1 were partial volume effect (43%), anatomic variants (39%), and cardiac (17%) and respiratory (1%) motion artifacts. CONCLUSION: Multi-detector row CT with reconstructed scans of 1.25-mm-thick sections enables accurate analysis of peripheral pulmonary arteries down to the fifth order on spiral CT angiograms.     

Sixteen-slice multidetector computed tomography pulmonary angiography: evaluation of cardiogenic motion artifacts and influence of rotation time on image quality

OBJECTIVE: To describe the site and severity of cardiogenic motion artifacts on 16-slice multidetector computed tomography (CT) angiograms of the pulmonary circulation and to determine the impact of the gantry rotation time on image quality. METHODS: Sixty-nine patients underwent nonelectrocardiographically gated 16-slice multidetector CT angiography of the pulmonary circulation with a rotation time of 0.5 second (group 1, n = 37) or 0.375 second (group 2, n = 32). All scans were prospectively analyzed for the presence of cardiogenic motion artifacts in the pulmonary arteries, defined as a blurring of the edges of the pulmonary arteries on lung window settings with or without an artifactual loss of enhancement in the arterial lumen on soft tissue windows ("pseudofilling defect"). In addition, the severity of pulmonary arterial blurring was recorded using a 4-point scale. RESULTS: Fifty-six patients (81%) had at least 1 pulmonary artery affected by cardiogenic motion artifacts. At the level of the central pulmonary arteries, movement artifacts responsible for a blurring of the arterial wall were present in 35 patients (51%), mainly observed at the level of the pulmonary trunk (n = 28, 41% of patients) and right main pulmonary artery (n = 23, 33% of patients); in 2 patients, motion artifact was responsible for a pseudoflap appearance within the arterial lumen (n = 2, 4% of patients). Motion artifacts at the level of lobar pulmonary arteries were noted only in the lower divisions of the lingula (n = 1, 1.5% of patients) and in the left lower lobe (n = 2, 3% of patients). At the level of the segmental pulmonary arteries, motion artifacts were most frequently found in the lower divisions of the left upper lobe (lingula) (n = 19, 27.5% of patients) and left lower lobe (n = 29, 42% of patients). At the subsegmental level, motion artifacts were most common in the lower divisions of the left upper lobe (lingula) (n = 30, 43.5% of patients) and left lower lobe (n = 35, 51% of patients). Pseudofilling defects were depicted at the segmental and subsegmental levels in 28 patients (41% of the study group), almost exclusively located in the lingula and left lower lobe. Cardiogenic motion artifacts were observed with a significantly lower frequency in group 2 (22 of 32 patients, 69%) than in group 1 (34 of 37 patients, 92%) (P = 0.0142), with a concurrent reduction in the frequency of pseudofilling defects identified in 20 patients (54%) in group 1 and in 8 patients (25%) in group 2 (P = 0.0142). CONCLUSION: The use of a 0.375-second rotation time enables significant reduction in the frequency of cardiogenic motion artifacts on 16-slice multidetector CT angiograms of the pulmonary circulation.     

Multi-detector row CT angiography of pulmonary circulation with gadolinium-based contrast agents: prospective evaluation in 60 patients

PURPOSE: To prospectively evaluate gadolinium dose safety and effectiveness for 16-detector pulmonary computed tomographic (CT) angiography. MATERIALS AND METHODS: Ethics committee approval and informed consent were obtained. Sixty patients with contraindications to iodine underwent CT of the pulmonary circulation with 0.5 mmol/L gadolinium chelate given at either 0.3 (n = 29, group A) or 0.4 (n = 31, group B) mmol/kg; clinical and biologic tolerances were evaluated. Enhancement of central and segmental pulmonary arteries was measured (poor enhancement, <100 HU; good, 100-150 HU; excellent, >150 HU). Subsegmental artery enhancement was assessed as similar or inferior to that of segmental arteries. Confidence in analysis of the pulmonary arterial bed was graded according to arterial enhancement: Grades 1-3, diagnostic images; grade 4, nondiagnostic. The main effectiveness parameter for comparison between groups A and B was diagnostic value of CT angiograms. Nonparametric statistics were used to analyze results. RESULTS: The mean (+/- standard deviation) contrast material volume was 50.09 mL +/- 8.45 (all patients: range, 30-64 mL; group A: 46.54 mL +/- 8.59; group B: 53.42 mL +/- 6.92). Diagnostic images were obtained in 55 (92%) patients, and confident analysis of pulmonary arteries to the subsegmental level was achieved in 26 (grade 1, 44%) and to the segmental level, in 21 (grade 2, 35%). Mean attenuation was higher in group B than in group A in central (180.61 HU +/- 53.85 vs 148.14 HU +/- 52.61; P = .04) and segmental (201.59 HU +/- 54.70 vs 164.73 HU +/- 59.26; P = .03) arteries. Number of diagnostic CT angiograms was higher (P = .02) in group B (n = 31 [100%]) than in group A (n = 24 [83%]). In both groups, mean enhancement of pulmonary arteries was significantly higher at 80 or 100 kV than at 120 kV. Renal function was impaired in two group A patients. CONCLUSION: Gadolinium chelates may be used as an alternative CT contrast agent in patients who cannot receive iodine.     

Tromboembolismo pulmonar en pacientes con COVID-19: estudio de prevalencia en un hospital terciario

IntroductionSARS-CoV-2, the virus responsible for the current pandemic, predominantly affects the respiratory tract, and a growing number of publications report the predisposition of patients with COVID-19 to develop thrombotic phenomena.ObjectiveTo determine the prevalence of pulmonary embolism in patients with COVID-19; to determine the possible relationship between the severity of pulmonary involvement and D-dimer levels; to analyze the location of pulmonary embolisms in patients with COVID-19 and to compare it with the location in patients without COVID-19.MethodsThis retrospective study analyzed all CT angiograms of the pulmonary arteries done in patients with suspected pulmonary embolisms between March 15 and April 30, 2020 and compared them with studies done in the same period one year earlier.ResultsWe included 492 pulmonary CT angiograms (342 (69.9%) in patients with COVID-19 and 147 (30.1%) in patients without COVID-19). The prevalence of pulmonary embolisms was higher in patients with COVID-19 (26% vs. 16.3% in patients without COVID-19, p=0.0197; relative risk=1.6). The prevalence of pulmonary embolisms in the same period in 2019 was 13.2%, similar to that of the group of COVID-19-negative patients in 2020 (p=0.43). There were no significant differences in D-dimer levels or the location of pulmonary embolisms between the two groups. CT showed moderate or severe pulmonary involvement in 78.7% of the patients with COVID-19.ConclusionsPatients with COVID-19 have an increased prevalence of pulmonary embolisms (26%), and most (78.7%) have moderate or severe lung involvement on CT studies. The location of pulmonary embolisms and the degree of elevation of D-dimer levels does not differ between patients with COVID-19 and those without.     

MRI in venous thromboembolic disease

We evaluated the ability of magnetic resonance (MR) imaging to detect deep venous thrombosis (DVT) and pulmonary embolism (PE). MR venography was performed on 217 patients suspected of having DVT. Cine-MR imaging of the pulmonary arteries was performed in 14 other patients who were thought to have PE based on other imaging studies. In a third group of 5 patients, MR pulmonary angiograms were performed in the sagittal and coronal planes with a multislice fast gradient recalled echo technique. All but one of the 217 MR venograms were technically adequate. In 72 patients with correlative imaging studies (venography and ultrasound) MR venography was 99% sensitive and 95% specific. On the basis of follow-up (mean 8.3 months), no false-negative MR venograms were detected in an additional 64 patients. In 11 other patients MR revealed a diagnosis other than DVT. Cine-MR showed PE in all 14 patients evaluated. MR pulmonary arteriography demonstrated filling defects consistent with acute PE in 2 of 3 patients with acute PE; in the third patient only a questionable filling defect was seen. Coarctations or webs were found in the pulmonary arteries of both patients with chronic PE. These preliminary data suggest that MR imaging may be able to evaluate both the peripheral venous and the pulmonary arterial component of venous thromboembolic disease. Further technical refinement and more extensive clinical experience will be required to establish the role of this method in diagnosing pulmonary embolism, but MR venography is now used routinely in our hospital for the diagnosis of deep venous thrombosis. Correspondence to: H. D. Sostman     

螺旋CT肺动脉造影对肺栓塞的诊断

目的：评价螺旋CT及其肺动脉造影诊断肺动脉栓塞（PE）的价值。方法：回顾性分析12例PE患,均行螺旋CT容积扫描,并在工作站进行图像后处理,获得肺动脉多平面重建图像及三维立体图像。结果：对12例196支肺动脉分支进行分析,受累率为46.4%;栓子发生在主肺动脉、左右肺动脉干及叶段肺动脉。多平面重建图像上表现为充盈对比剂血管内有充盈缺损区,或其远侧方无对比剂充填区。肺动脉成像示,主干血管内可见充盈缺损影,或呈截断状影;叶栓塞或段栓塞亦呈突然“截断状”,其远侧方肺动脉分支不显影或呈纤维状。结论：螺旋CT肺动脉造影不仅可以获得轴位图像,而且可以获得立体图像,可多轴向旋转观察PE部位,是诊断叶或段以上PE可靠而直观的检查方法。     

Comparing the interpretations of CT pulmonary angiograms by attending and resident radiologists: can residents identify life-threatening pulmonary emboli in hospitalized patients?

Objective: CT pulmonary angiography is now often the first-line investigation for pulmonary emboli. When these studies are performed after hours in teaching hospitals, they are often initially interpreted by trainees. It is of great significance whether the interpretations of trainees and certified radiologists with regard to the presence of pulmonary emboli on CT pulmonary angiograms correspond, because of the morbidity and mortality of both the condition and its treatment. Material and methods: Twenty-five consecutive CT pulmonary angiograms (CTPAs) of hospitalized patients were viewed at lung and soft tissue windows both on a workstation and on hard copies, at the observers' discretion. Each CTPA was divided into 28 arterial zones based on pulmonary anatomy (including the subsegmental arteries), giving a total of 700 arterial zones, and analyzed retrospectively and independently by two cross-sectional imaging specialists and four residents. Each arterial segment was rated with regard to pulmonary embolus as either high, intermediate, or low probability or not visualized. The kappa (Κ) test, which tests for interobserver agreement, was used for statistical analysis. Results: At the time of the scan all patients were hospitalized for underlying conditions. Of the 25 patients studied, 9 were referred from the ICU, 7 experienced severe acute shortness of breath and respiratory failure, 5 were post-partum women, 2 had had a recent stroke, 1 patient had antithrombin III deficiency, and 1 had a diagnosis of breast cancer. The incidence of pulmonary emboli was 44%. For the main pulmonary arteries interobserver agreement was good (Κ=0.61) and for the segmental pulmonary arteries it was fair (Κ=0.26). For the subsegmental arteries interobserver agreement was poor (Κ=0.16). The zones where interobserver agreement was greatest (Κ>0.4) were the left main, left lower lobe, and the right main pulmonary arteries. Interobserver agreement was poorest (Κ<0.05) in the left interlobar, left lower lobe lateral basal segment, right lower lobe superior segment, and left lower lobe superior segment branches. None of the patients expired due to pulmonary emboli. Conclusion: Most life-threatening pulmonary emboli requiring urgent treatment are the more central emboli. This study demonstrates that trainees and certified radiologists can make similar conclusions regarding these central pulmonary emboli in hospitalized patients and that preliminary interpretations by trainees should not therefore adversely affect patient care. Electronic Publication     

MRI of congenital abnormalities of the great arteries

ECG-gated MRI was performed at 0.3 T or 1.0 T in 19 patients, aged 6 years to 18 years, for suspected congenital abnormalities of the aorta (13 patients) or pulmonary artery (six patients). Seventeen of the patients were also evaluated by echocardiography, and 14 had angiograms. In 11 patients, MRI demonstrated lesions that echocardiography either failed to visualize or found inconclusive, including supravalvar aortic stenosis (one patient), coarctation of the aorta (three patients) hypoplastic aortic arch (one patient), and pulmonary artery hypoplasia or stenosis (six patients). MRI complemented echocardiographic diagnosis in four patients with Marfan's syndrome and in one with coarctation. One mild recurrent coarctation demonstrated angiographically was not visualized by MRI or echocardiography. The eight other angiographic studies of the aorta confirmed MRI findings. In all six MRI studies of the pulmonary arteries, obstructive lesions were revealed that had not been completely visualized on echocardiography or angiography. MRI is an excellent noninvasive method of depicting congenital abnormalities of the great arteries and may provide otherwise unobtainable information.     

Acute pulmonary embolism: diagnostic value of digital subtraction angiography

Digital subtraction angiography (DSA) performed via a peripheral vein was compared prospectively with selective conventional pulmonary angiography (CPA) in 54 patients suspected of having pulmonary embolism (PE). All patients also underwent ascending venography. In contrast to the conventional pulmonary angiograms, all of which were considered satisfactory, 13 of 54 digital subtraction angiograms (24%) were technically unsatisfactory. The interpretable digital subtraction angiograms had 81% sensitivity and 64% specificity. With DSA, one cannot exclude the diagnosis of PE on the basis of normal angiograms (27% false-positive results) as one can with perfusion scanning. On the other hand, DSA showed good sensitivity (94%) in medium to major PE. Therefore it may be the technique of choice in the screening of life-threatening PE for which curative emergency treatment with thrombolytic agents or embolectomy is often necessary.     

Projection arteriography and venography: initial clinical results with MR

Motion currently limits the applications of magnetic resonance (MR) angiography in certain regions of the body. To overcome this problem, a series of breath-hold, two-dimensional, flow-compensated gradient-echo images were acquired. These images were then processed by means of the maximum intensity projection algorithm to produce projection angiograms. The method was evaluated in 10 healthy subjects and in 12 patients and validated by comparing conventional angiograms, contrast material-enhanced computed tomographic scans, and duplex sonograms with MR projection arteriograms and venograms of the chest, abdomen, and pelvis. The aorta and pulmonary arteries and their branches were demonstrated, as was detailed anatomy of the hepatic and portal venous systems and inferior vena cava. Renal arteries and veins could be studied in both native and transplanted kidneys. The method permits determination of flow direction and differentiation of arteries and veins and is superior to three-dimensional acquisition techniques for imaging slow blood flow. Initial results suggest that the method may have clinical applications for a variety of vascular disorders.     

Chronic major-vessel thromboembolic pulmonary artery obstruction: appearance at angiography.

The pulmonary angiograms of 250 patients evaluated for chronic thromboembolic pulmonary hypertension were reviewed. Pulmonary thromboendarterectomy was performed in each of these individuals, and the surgical findings were correlated with abnormal angiographic patterns. The pulmonary angiographic findings suggestive of chronic thromboembolic disease included "pouching" defects, webs or bands, intimal irregularities, abrupt vascular narrowing, and complete vascular obstruction. Pouching is reported by the authors to be a previously undescribed angiographic feature of this disease. Carefully obtained and properly interpreted pulmonary angiograms are necessary to confirm the diagnosis of operable chronic thromboembolic disease. Differential diagnostic possibilities should be considered prior to a decision to perform surgical correction.     

Comparison of left coronary and laevo-phase pulmonary angiograms in detecting left atrial thrombi in rheumatic mitral stenosis

We have compared the diagnostic accuracy of left coronary and laevo-phase pulmonary angiograms in detecting left atrial thrombi in 27 consecutive patients with rheumatic mitral stenosis who underwent both these procedures prior to open-heart surgery. In 10 patients, both procedures were 'positive' for thrombus, confirmed at subsequent surgery in all instances (true positive). Both procedures were negative for thrombus in 11 patients, and none of these patients showed thrombi at subsequent surgery (true negative). Left coronary angiography only was positive for thrombus in one patient in whom no thrombus was found at surgery. Laevo-phase pulmonary angiography only was positive for thrombus in five patients, two of whom had thrombus at subsequent surgery. The sensitivity, specificity and predictive accuracy of left coronary angiogram were 83.3% and 93.3% and 90.9% and that of laevo-phase pulmonary angiogram 100%, 80% and 80% respectively. Laevo-phase pulmonary angiograms showed higher sensitivity and left coronary angiograms showed higher specificity for angiographic diagnosis. However, the differences were found to be statistically insignificant. Angiography is a reliable method for detecting left atrial thrombi if both left coronary and pulmonary angiograms are performed and both procedures are positive or negative for thrombus.     

Multi-detector row spiral CT pulmonary angiography: comparison with single-detector row spiral CT.

PURPOSE: To compare vascular conspicuity and ability to connect pulmonary arterial branches on pulmonary angiograms obtained with helical multi-detector row computed tomography (CT) with those on pulmonary angiograms obtained with helical single-detector row CT. MATERIALS AND METHODS: Of 93 consecutive patients suspected of having pulmonary embolism, 48 underwent scanning with multi-detector row CT and 45 with single-detector row CT; scans were obtained in 9 seconds and 28 seconds with 2.5-mm and 3.0-mm collimation, respectively. The lungs were divided into three zones: central, middle, and peripheral. Two independent observers used five-point grading scales. RESULTS: Conspicuity of pulmonary arteries in the central zone was ranked equal (median of 5), but in the middle and peripheral zones it was significantly higher at multi-detector row CT than at single-detector row CT (median 5 vs 4 and 4 vs 3, P < .001, respectively). In addition, multi-detector row CT improved the ability to connect peripheral arteries with their more centrally located pulmonary artery of origin in the peripheral but not the middle zone on transverse images and in both zones on multiplanar images. Viewing with a modified window setting (width, 1,000 HU; level, -100 HU) significantly increased pulmonary arterial conspicuity. Contrast material column in the pulmonary arteries was significantly more homogeneous at multi-detector row CT. CONCLUSION: Use of multi-detector row CT significantly improves pulmonary arterial visualization in the middle and peripheral lung zones.     

The incidence and patterns of pulmonary artery involvement in Takayasu's arteritis

The pulmonary arterial anatomy in 44 patients with Takayasu's arteritis was examined by intravenous digital subtraction angiography (IV-DSA) on an outpatient basis using centrally delivered, small-volume, bolus injections of an ionic, water soluble contrast medium. Diagnostic pulmonary angiograms were obtained in 42 patients (95.4%) without complication. Angiographically evident pulmonary arterial involvement was seen in six patients (14.3%). The pulmonary involvement was not suspected clinically in any patient and the chest radiographs were abnormal in only two patients (33%). The angiographic spectrum of systemic arterial involvement was the same irrespective of the presence or absence of pulmonary arterial involvement. The pulmonary arterial pressures were measured in two patients with abnormal pulmonary angiograms and were found normal. Follow up IV-DSA in one of these patients 16 months after immuno-suppressive therapy showed no change in the pulmonary angiographic picture.     

Pulmonary embolism: comprehensive diagnosis by using electron-beam CT for detection of emboli and assessment of pulmonary blood flow

P:URPOSE: To comprehensively assess thoracic anatomy and pulmonary microcirculation in pulmonary embolism by using computed tomographic (CT) angiography of the pulmonary arteries combined with functional CT imaging of blood flow. MATERIALS AND METHODS: Twenty-two patients suspected of having acute pulmonary embolism underwent contrast material-enhanced thin-section electron-beam CT angiography of the pulmonary arteries. In addition, in each patient, a dynamic multisection blood flow CT study was performed on a 7.6-cm lung volume with electrocardiographic gating. Pulmonary blood flow was calculated, and perfusion parameters were visualized on color-coded maps. The color-coded maps and CT angiograms were independently evaluated, segment by segment, by two readers for perfusion deficits and the presence of clots, respectively. The results were compared. RESULTS: Mean pulmonary blood flow was 0.63 mL/min/mL in the occluded segments versus 2.27 mL/min/mL in the nonoccluded segments (P: =.001). The sensitivity and specificity of perfusion maps for the presence of segmental pulmonary embolism compared with those of CT angiography were 75.4% and 82.3%, respectively, with positive and negative predictive values of 79.6% and 84.7%, respectively. The false-negative findings were caused mainly by partial occlusion of vessels. In eight patients, a substantial alternative or additional pathologic entity was diagnosed. CONCLUSION: By combining CT angiography and dynamic CT imaging, a comprehensive and noninvasive diagnosis of thoracic structure and function is feasible with a single modality.