Multidetector CT Pulmonary Angiography Research Articles

Sensitivity and specificity of chest ultrasound in the diagnosis of pulmonary embolism in the emergency department: A case-control study.

The present study was designed to evaluate the role of chest ultrasound in the diagnosis of acute pulmonary embolism (PE) and determine its accuracy using multi-detector CT-pulmonary angiography (MD-CTPA) as a gold standard technique for PE diagnosis. A prospective case-control study was performed with 75 patients who presented to the emergency department of Minia Cardiothoracic University Hospital with clinical suspicion of PE. All patients were evaluated clinically and by laboratory tests to assess the risk of PE. Thoracic ultrasound (TUS) was then performed for all patients for signs suggestive of PE. Finally, MD-CTPA was performed to confirm or exclude the presence of PE. Patients were subdivided into two groups according to the result of MD-CTPA; group I (patients with PE) and group II (control group without PE). In our study, PE was present in the lower lobe in 75% of cases, then in the middle in 13% and in the upper lobe in 3.8% of cases. The majority of lesions in TUS were wedge-shaped lesions. No vascular flow was detected in 83% of PE-confirmed patients. The current study revealed that TUS has 81.25% sensitivity, 95% specificity, 98.3% positive predictive value, 77.2% negative predictive value and 87% accuracy in the diagnosis of PE. Univariate regression analysis revealed that the presence of wedge-shaped pleural-based lesions in grayscale US and the absence of flow signals by colour Doppler sonography (CDS) increase the possibility of PE. Wedge-shaped pleural-based lesions increase the possibility of PE by 1.48 times (P=0.0001), and the absence of flow signals by CDS increases the possibility of PE by 92.89 times (P=0.00001). Multivariate regression analysis revealed that adding absent flow signals by CDS to wedge-shaped pleural-based lesions by grayscale US increases the possibility of a PE diagnosis by 50.28 times (P=0.001). Chest ultrasound is a simple, safe, noninvasive, inexpensive, bedside diagnostic radiological technique that can be used in the emergency department for suspected PE or as an alternative to MD-CTPA when CTPA is contraindicated. Wedge-shaped lesions and the absence of flow signals by CDS increase the diagnostic value of ultrasound for PE.

Role of multidetector CT in predicting patient outcome in cases of pulmonary embolism: correlation between imaging findings, ICU admissions and mortality rate

BackgroundPulmonary embolism (PE) is a critical medical condition that requires prompt diagnosis and treatment to avoid serious morbidity and mortality risk. Multidetector CT pulmonary angiography (CTPA) is considered the first-line imaging modality for suspected acute PE. The presence of right heart strain, which supports the diagnosis, requires special attention. The aim of our retrospective study is to assess the reliability of CTPA hemodynamic indices in predicting patients’ outcome in cases of PE.ResultsSixty patients were included in our study. CTPA parameters including main pulmonary artery (MPA) diameter, left ventricle (LV) diameter, right ventricle (RV)/LV ratio, and septal deviation had a clinical prognostic value for short-term 30-day mortality and ICU admission. Statistically significant relationship between MPA diameter > 29 mm, LV diameter, RV/LV ratio > 1, left-sided septal deviation and contrast reflux into the IVC/distal hepatic veins with ICU admission was observed with p values 0.031, 0.000, 0.000, 0.005 and 0.028 respectively. There was a statistically significant correlation between MPA diameter > 29 mm, LV diameter, RV/LV > 1 ratio and septal deviation with 30-day mortality with p values of < 0.001, 0.001, < 0.001 and 0.015 respectively. No significant correlation was found between 30-day mortality and contrast reflux to IVC with p value of 0.070.ConclusionsCTPA measurements including MPA diameter, RV/LV ratio and septal deviation were found to be significantly correlated to ICU admission and 30-day mortality as predictors for PE severity. CT contrast reflux was found to be correlated to ICU admission; however, it was not significantly correlated to 30-day mortality.

Ventilation-Perfusion Scan Is Superior to CT Pulmonary Angiography in Detection of Chronic Thromboembolic Pulmonary Hypertension in SCD Adults

▪Background: Pulmonary hypertension (PH) in adults with sickle cell disease (SCD) is associated with significant morbidity and early mortality. Venous thromboembolism (VTE) is common in SCD and affects about 25% of SCD adults. Although not generally considered a major cause of PH, chronic thromboembolic pulmonary hypertension (CTEPH) has been noted, and is probably more common than realized in patients with SCD. National guidelines recommend that CTEPH should be excluded in any patient suspected to have PH. Imaging techniques, including ventilation-perfusion (V/Q) scintigraphy, multidetector CT pulmonary angiography (CTPA), high-resolution CT (HRCT), pulmonary digital subtraction angiography (DSA), and magnetic resonance angiography have been used in identifying CTEPH as the cause of PH. Several studies have shown that V/Q scintigraphy is able to distinguish patients with CTEPH from other causes of PH, to the extent that normal V/Q scintigraphy can comfortably rule out CTEPH. However, data on V/Q and associated outcomes on SCD are limited. In this study, we report a retrospective analysis of V/Q scintigraphy findings and CTPA for assessing PH as validated by right heart catherization. We also report associated outcomes of the V/Q findings with prospectively collected data in the adult SCD patients.Methods: This study was approved by the Institutional Review Board at the National Institutes of Health (NIH), and all subjects provided written informed consent to one or more studies.A total of 142 consecutive patients, (83 women, aged 40.1 ± 13.7 years, HbSS 124 (87%) suspected of having PH were prospectively enrolled (Table 1). All patients underwent V/Q scanning, echocardiography (ECHO), six-minute walk testing (6MWT); 52 patients underwent CTPA, and 63 patients had right heart catheterization (RHC) performed. Interpretation of V/Q images was based on the refined Pulmonary Embolism Diagnosis criteria. High-probability and intermediate-probability V/Q scan findings were considered to be positive or abnormal, and very low, low-probability/normal V/Q scan findings were considered negative or normal V/Q.Results: V/Q scan was abnormal in 58 (40.8%) patients (high probability and intermediate probability in 26 (18.3%), 32 (22.5%), respectively), and was low probability/normal in 84 (59.2%) patients (Table 1). CTPA was positive for PE in 17 (32.7%) patients. Patients with positive CTPA were more likely to have abnormal V/Q [ abnormal V/Q 14 (82.4%) vs. normal V/Q 3(17.6); p=0.032], but in those with negative CTPA (n=35), V/Q was abnormal in 18 (51.4%) (Table 2). RHC confirmed PH (mean pulmonary artery pressure (mPAP) ≥25mmHg) in 45/63 patients, of which 33 (73.3%) had abnormal V/Q compared to 12 (26.6%) with normal V/Q scans, (p=0.0001). Among those with no PH by RHC (n=18), only one patient showed abnormal and 17 normal V/Q (5.6% vs 94.4%, respectively, (p<0.001). Thirty-two patients had a complete dataset of V/Q, CTPA and RHC, and clearly there was greater concordance of results between RHC with V/Q than CTPA (Table 3). Subjects with SCD and abnormal V/Q demonstrated significantly worse hemodynamic severity (mPAP=35.95 ± 9.20 vs.24.8± 12.09 mmHg, p<0.001; right atrial pressure= 9.59± 4.53 vs. 9.59± 4.53mmHg, p<0.001; transpulmonary gradient 21.8 ± 10.4 vs. 12.16± 11mmHg, p=0.001, and pulmonary vascular resistance=238.3 ± 135 vs.120.5 ± 134.9 dynes.s.cm-5, p=0.001 ) and abnormal cardiopulmonary markers of clinical severity compared to those with a normal V/Q group, including higher TRV (3.5±0.6 vs. 3±0.5 m/s, p=0.01) and poor exercise capacity (6MWD 379.7±117.3 vs. 438.8±115.5m, p<0.001). Over a median follow-up of 6 years with a maximum follow-up of 15 years, total of 34 deaths were observed (Fig 1). The all-cause mortality was higher in the abnormal V/Q 19 (56%) group compared to those with normal V/Q 15 (44%) patients (log-rank test, p<0.001, Hazard Ratio=2.54).Conclusion: Using RHC as the benchmark, our data demonstrates that V/Q scan is superior in detecting CTEPH in adults with SCD. Additionally, abnormal V/Q scan is associated with worse hemodynamics by RHC, poor functional capacity and increased mortality. We recommend frequent use of V/Q in the evaluation of dyspnea in adults with SCD as confirmation of CTEPH has important implications in management. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Multidetector computed tomography pulmonary angiography in childhood acute pulmonary embolism.

Pulmonary embolism is a life-threatening condition affecting people of all ages. Multidetector row CT pulmonary angiography has improved the imaging of pulmonary embolism in both adults and children and is now regarded as the routine modality for detection of pulmonary embolism. Advanced CT pulmonary angiography techniques developed in recent years, such as dual-energy CT, have been applied as a one-stop modality for pulmonary embolism diagnosis in children, as they can simultaneously provide anatomical and functional information. We discuss CT pulmonary angiography techniques, common and uncommon findings of pulmonary embolism in both conventional and dual-energy CT pulmonary angiography, and radiation dose considerations.

Akut pulmoner tromboemboli sonrası gelişen kronik tromboembolik pulmoner hipertansiyon sıklığı

Chronic thromboembolic pulmonary hypertension (CTEPH) is a curable and partially preventable complication, with a substantial incidence, leading to severe morbidity and mortality. The aim of the present study was to find out the incidence of CTEPH secondary to acute pulmonary thromboembolism (PTE) using non-invasive procedures such as ventilation/perfusion (V/Q) scintigraphy and pulmonary multidetector CT (MDCT) angiography in determining the diagnosis of CTEPH. The study included a total of 99 patients diagnosed with initial PTE between January 2010 and December 2012. The patients who received anticoagulant therapy at least for three months underwent transthoracic echocardiography (TTE) (n= 85). Thirty one patients with a SPAP value > 30 mmHg and/or an evidence of right ventricular dysfunction in TTE underwent MDCT pulmonary angiography and V/Q scintigraphy. The patients with an evidence of residual chronic thromboembolic signs in MDCT pulmonary angiography and/or segmental perfusion defect(s) in V/Q scintigraphy underwent right heart catheterization (RHC) (n= 7). The mean PAP was measured, and a vasoreactivity test was performed. During RHC, a non-contrast medium was delivered to the pulmonary arteries for pulmonary arteriography imaging. Among patients diagnosed with PTE, 44 were male and 55 were female. The mean age was 60 ± 17 years. Of these patients, 63.6% had history of at least one additional disease and at least one risk factor for PTE. During diagnosis, 24 subjects were considered having massive, 61 submassive and 14 non-massive PTE. Nineteen (19.1%) patients received thrombolythic therapy. Other 80 (80.8%) patients received standard anticoagulant therapy with an INR value within the therapeutic range. In 79.8% of patients, thromboembolism was bilateral, and it was unilateral in 21.8%. After a minimum of 1 year, and maximum of 2 years follow up five subjects (5.5%) were diagnosed with CTEPH. The univariate analysis showed no association between the development of CTEPH and factors like; age, etiologic risk factors for PTE, receiving thrombolytic treatment, prevalence and type of PTE. Potentially preventabl complication of pulmonary embolism; CTEPH, had a substantial incidence during follow-up.

Prediction of short term outcome of pulmonary embolism: Parameters at 16 multi-detector CT pulmonary angiography

PurposeTo evaluate the accuracy of computed tomography pulmonary angiography (CTPA) parameters, for predicting short-term mortality in patients with acute pulmonary embolism (PE). Materials and methodsThirty-two patients with proven PE had CT pulmonary angiography were included in the study. The clot burden using the Qanadli score (QS), and the right ventricular dysfunction (RVD) parameters were assessed on CT by calculating right ventricular/left ventricular (RV/LV) diameter ratios, interventricular septum abnormality, inferior vena cava contrast reflux, azygous vein and superior vena cava measures. Contrast density in pulmonary artery and descending aorta was evaluated for all patients. Patients were followed up for 30days and then classified as survivors or non survivors. ResultsThirty-two patients were included in the study, 23 (71.8%) of them were classified as survivors, and the other nine (28.1%) patients died within the first month (non survivors). There was a positive, but weak correlation between the Qanadli score and the short term mortality (P value=0.05). There was a statistically significant relationship between the RV/LV ratio and PE-related mortality, with a P value<0.001. Also, there was a good correlation between degree of IVC reflux and PE outcome (P<0.001). The PA/AO diameter ratio, SVC diameter and azygous vein diameter showed no statistically significant difference between survivors and non survivors. ConclusionsCTPA findings that may predict short term mortality are the high grades of inferior vena cava reflux, RV/LV diameter ratio more than 1.2, and clot burden >18 according to the Qanadli score and to a lesser degree the interventricular septum abnormality.

Accuracy of Point-of-Care Multiorgan Ultrasonography for the Diagnosis of Pulmonary Embolism

Presenting signs and symptoms of pulmonary embolism (PE) are nonspecific, favoring a large use of second-line diagnostic tests such as multidetector CT pulmonary angiography (MCTPA), thus exposing patients to high-dose radiation and to potential serious complications. We investigated the diagnostic performance of multiorgan ultrasonography (lung, heart, and leg vein ultrasonography) and whether multiorgan ultrasonography combined to Wells score and D-dimer could safely reduce MCTPA tests. Consecutive adult patients suspected of PE and with a Wells score &gt; 4 or a positive D-dimer result were prospectively enrolled in three EDs. Final diagnosis was obtained with MCTPA. Multiorgan ultrasonography was performed before MCTPA and considered diagnostic for PE if one or more subpleural infarcts, right ventricular dilatation, or DVT was detected. If multiorgan ultrasonography was negative for PE, an alternative ultrasonography diagnosis was sought. Accuracies of each single-organ and multiorgan ultrasonography were calculated. PE was diagnosed in 110 of 357 enrolled patients (30.8%). Multiorgan ultrasonography yielded a sensitivity of 90% and a specificity of 86.2%, lung ultrasonography 60.9% and 95.9%, heart ultrasonography 32.7% and 90.9%, and vein ultrasonography 52.7% and 97.6%, respectively. Among the 132 patients (37%) with multiorgan ultrasonography negative for PE plus an alternative ultrasonographic diagnosis or plus a negative D-dimer result, no patients received PE as a final diagnosis. Multiorgan ultrasonography is more sensitive than single-organ ultrasonography, increases the accuracy of clinical pretest probability estimation in patients with suspected PE, and may safely reduce the MCTPA burden. ClinicalTrials.gov; No.: NCT01635257; URL: www.clinicaltrials.gov.

Chronic Thromboembolic Pulmonary Hypertension (CTEPH) – Potential Role of Multidetector-Row CT (MD-CT) and MR Imaging in the Diagnosis and Differential Diagnosis of the Disease

Chronic thromboembolic pulmonary hypertension (CTEPH) can be defined as pulmonary hypertension (resting mean pulmonary arterial pressure of 25 mm Hg or more determined at right heart catheterization) with persistent pulmonary perfusion defects. It is a rare, but underdiagnosed disease with estimated incidences ranging from 0.5% to 3.8% of patients after an acute pulmonary embolism (PE), and in up to 10% of those with a history of recurrent PE. CTEPH is the only form of pulmonary hypertension that can be surgically treated leading to normalization of pulmonary hemodynamics and exercise capacity in the vast majority of patients. The challenges for imaging in patients with suspected CTEPH are fourfold: the imaging modality should have a high diagnostic accuracy with regard to the presence of CTEPH and allow for differential diagnosis. It should enable detection of patients suitable for PEA with great certainty, and allow for quantification of PH by measuring pulmonary hemodynamics (mPAP and PVR), and finally, it can be used for therapy monitoring. This overview tries to elucidate the potential role of ECG-gated multidetector CT pulmonary angiography (MD-CTPA) and MR imaging, and summarizes the most important results that have been achieved so far. Generally speaking, ECG-gated MD-CTPA is superior to MR in the assessment of parenchymal and vascular pathologies of the lung, and allows for the assessment of cardiac structures. The implementation of iodine maps as a surrogate for lung perfusion enables functional assessment of lung perfusion by CT. MR imaging is the reference standard for the assessment of right heart function and lung perfusion, the latter delineating typical wedge-shaped perfusion defects in patients with CTEPH. New developments show that with MR techniques, an estimation of hemodynamic parameters like mean pulmonary arterial pressure and pulmonary vascular resistance will be possible. CT and MR imaging should be considered as complementary investigations providing comprehensive information in patients with CTEPH.

Diagnostic accuracy of three-dimensional contrast-enhanced MR angiography at 3-T for acute pulmonary embolism detection: Comparison with multidetector CT angiography

BackgroundThree-dimensional contrast-enhanced MR pulmonary angiography (MRPA) is a suitable option for pulmonary embolism (PE) detection. However, there have been few reports on the diagnostic accuracy of MRPA for PE detection in a 3-T MR system. The purpose of this study was to evaluate the accuracy of MRPA in a 3-T MR system to detect acute PE with multidetector CT pulmonary angiography (CTPA) as reference standard. MethodsTwenty-seven patients (18 males and 9 females, mean age 38.9±14.4years) underwent both MRPA and CTPA within 3days (range, 0–3days) for evaluating PE. Pulmonary emboli in MRPA were independently analyzed on a per-patient and per-lobe basis by two radiologists. CTPA was regarded as reference standard, which was evaluated by another two radiologists in consensus. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for PE detection were calculated. Weighted κ values were calculated to evaluate agreement between readers. ResultsTwenty-four patients had PE in 55 lung lobes in CTPA, while 3 patients had no PE detected. Readers 1 and 2 correctly detected 47 and 46 lung lobes having clots in 24 and 23 patients, corresponding to sensitivities, specificities, PPV, NPV, and accuracies of 100%, 100%, 100%, 100%, 100%; 100%, 66.7%, 96.0%, 100%, 96.4% on a per-patient basis and 85.5%, 100%, 100%, 90.9%, 94.1%; 83.6%, 93.7%, 90.2%, 89.2%, 89.6% on a per-lobe basis; respectively. Excellent inter-reader agreement (κ values=1.00 and 0.934; both P<0.001) were found for detecting PE on a per-patient and per-lobe analysis. ConclusionThree-dimensional contrast-enhanced MRPA with a 3-T MR system is a suitable alternative modality to CTPA to detect PE on a per-patient basis based on this small cohort study.

Does the anatomic distribution of acute pulmonary emboli at MDCT pulmonary angiography in oncology-population differ from that in non-oncology counterpart?

ObjectiveTo compare the prevalence and the anatomic distribution of acute PE in oncology patients with those of non oncology patients using multidetector CT (MDCT) pulmonary angiography. Material and methodsWe prospectively reviewed 80 consecutive patients having pathologically proven neoplasms and clinically suspected to have acute PE. Similarly, the other group included 80 consecutive age-matched patients with the clinical suspicion of acute PE, nonetheless, with irrelevant oncologic history. All patients underwent MDCT pulmonary angiography. The PE involvement according to pulmonary arterial level was classified. Lobar location was also recorded using standard nomenclature. ResultsTwenty six patients (33%) of the 80 oncology patients compared to 19 patients (24%) of the 80 non oncology group had acute PE at pulmonary MDCT angiographic examinations. Among the oncology patients, acute PE was located in the main pulmonary artery in 7 (13%), the lobar pulmonary artery in 22 (40%), the segmental pulmonary artery in 17 (31%) and the subsegmental pulmonary artery in 9 (16%) patients. Whereas in the non oncology group, the level of involvement of PE was the main pulmonary artery in 4 (10%) patients, the lobar pulmonary artery in 17 (40%), the segmental pulmonary artery in 15 (36%) and the subsegmental pulmonary artery in 6 (14%). Alternatively, there was a lower lobar predominance in both groups. ConclusionThe prevalence of acute PE is more common among oncology patients than previously reported and has a slight predilection to a central distribution.

Comparison of non-invasive diagnostic tests to multi-detector CT pulmonary angiography for the diagnosis of pulmonary embolism

ContextAcute pulmonary embolism (PE) remains a diagnostic and therapeutic challenge to physicians. There are various non-invasive diagnostic modalities been suggested to diagnose pulmonary embolism. AimWe tried to find the performance of various non-invasive investigations in comparison to multi-detector Computerized Tomography (MDCT pulmonary angiography for the diagnosis of PE). Settings and designA prospective cohort study was conducted in 80 hospitalized medical patients. Materials and methodsThere were 80 patients with Wells score > 2 who were included. The demographic data, non-invasive investigations, and MDCT pulmonary angiography were conducted in these patients. The sensitivity (SEN), specificity (SPE), positive predictive value (PPV), and negative predictive value (NPV) were calculated for each test. ResultsOut of 80 patients, 77.5% patients were with Wells score 3–6 and 22.5% patients were with Wells score more than 6. The test with highest sensitivity was d-dimer (SEN – 90%, P = 0.091) followed by PAH on TTE (SEN – 83%, PPV – 86%, P = 0.006). The most specific test was ECG showing S1Q3T3 (SPE – 100%, P = 0.421), followed by Wells score > 6 (SPE – 91%, P = 0.211). There was no test with sensitivity and specificity more than 90% ConclusionIn all patients with intermediate to high-risk probability MDCT pulmonary angiography is the most accurate test to diagnose PE and should be performed at the earliest. The combination of 2-dimensional ECHO and d-dimer can be used in patients with a high clinical suspicion of PE on pre-test probability where MDCT pulmonary angiography is not possible.

Diagnosis of chronic thromboembolic pulmonary hypertension: prospective comparison of ventilation-perfusion scintigraphy and multidetector CT pulmonary angiography

Objective To compare the diagnostic efficacy of V/Q scintigraphy and CT pulmonary angiography (CTPA) for chronic thromboembolic PAH (CTEPH).Methods A total of 133 consecutive patients (54 males,79 females,age:(43.1 ± 14.9) years) suspected of CTEPH were prospectively enrolled in the study.All patients underwent V/Q scintigraphy,CTPA and pulmonary angiography within 7 d of clinical presentation.Pulmonary angiography was considered as the gold standard.The diagnosis of CTEPH by V/Q scan was classified as high,intermediate and low probability,and that by CTPA was classified as present,absent and indeterminate.Kappa test was used to analyze the concordance between the image modalities.Results Fifty-one patients (38.3％) had a final diagnosis of CTEPH.The other 82 patients were respectively diagnosed with IPAH (n =60),pulmonary vasculitis (n =19) and atrial septal defect (n =3).The sensitivity,specificity and accuracy of V/Q scan were 96.1％ (49/51),75.6％ (62/82) and 83.5％ (111/133),respectively,when CTEPH with high probability was considered positive.The sensitivity,specificity and accuracy of V/Q scan were 100％ (51/51),73.2％ (60/82) and 83.5％ (111/133),respectively,when CTEPH with high or intermediate probability was considered positive.The sensitivity,specificity and accuracy of CTPA were 92.2％ (47/51),92.7％ (76/82) and 92.5％ (123/133),respectively.When CTEPH with high probability by V/Q scan was considered positive,the concordance between V/Q scan and CTPA was 80.5％ (107/133) (Kappa =0.612,P ＜ 0.001).Conclusions V/Q scan has a higher sensitivity for the diagnosis of CTEPH than CTPA.CTPA has a higher specificity than V/Q scan to differentiate PAH caused by other diseases,especially pulmonary vasculitis,from CTEPH.Combining V/Q scan and CTPA may improve the diagnostic accuracy of CTEPH. Key words: Pulmonary embolism; Hypertension,pulmonary; Radionuclide imaging; Technetium; Tomography,X-ray computed; DTPA

Intravenous contrast medium administration at 128 multidetector row CT pulmonary angiography: Bolus tracking versus test bolus and the implications for diagnostic quality and effective dose

To investigate the effects of a test bolus protocol contrast medium administration on diagnostic image quality in computed tomography pulmonary angiography (CTPA). Fifty patients referred for exclusion of pulmonary embolism underwent CTPA using a test bolus protocol CTPA at 120 kVp and were compared with 50 patients undergoing CTPA using a standard bolus-tracking protocol at 120 kVp, via assessment of attenuation, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) seen in the pulmonary arteries (PAs). An additional group of 10 non-obese patients who underwent CTPA using a test bolus protocol performed at 100 kVp were also analysed. Mean effective dose was calculated from the dose-length product, using standard conversion factors. The test bolus protocol showed significantly higher attenuation, SNR, and CNR in the pulmonary vasculature down to the segmental level compared to bolus-tracking CTPA (p < 0.0001). There was no significant difference in effective dose between the test bolus and bolus tracking cohorts. The additional group of test bolus CTPA examinations performed at 100 kVp had a significantly reduced effective dose in comparison to both test bolus CTPA at 120 kVp and bolus-tracking CTPA at 120 kVp (p < 0.005) yet maintained mean PA attenuation to segmental level significantly better than bolus-tracking CTPA performed at 120 kVp and comparable to the test bolus cohort performed at 120 kVp. Test bolus contrast administration should be used as an optimal protocol. Performing test bolus CTPA at 100 kVp, as opposed to 120 kVp, significantly reduces dose without compromising PA attenuation in non-obese subjects.

Children Suspected Of Having Pulmonary Embolism: Multidetector CT Pulmonary Angiography—Thromboembolic Risk Factors and Implications for Appropriate Use

Children Suspected Of Having Pulmonary Embolism: Multidetector CT Pulmonary Angiography—Thromboembolic Risk Factors and Implications for Appropriate Use

Intraindividual comparison of gadolinium- and iodine-enhanced 64-slice multidetector CT pulmonary angiography for the detection of pulmonary embolism in a porcine model

This study is an evaluation of the diagnostic accuracy of gadolinium-enhanced computed tomography pulmonary angiography (CTPA) for the detection of pulmonary embolism (PE) in comparison with iodine-enhanced CTPA. PE was induced in five anesthetized pigs by administration of blood clots through an 11-F catheter inside the jugular vein. Animals underwent CTPA in breathhold with i.v. bolus injection of 50ml gadopentetate dimeglumine (0.4mmol/kg, 4ml/s). Subsequently, CTPA was performed using the same imaging parameters but under administration of 70ml nonionic iodinated contrast material (400mg/ml, 4ml/s). All images were reconstructed with 1mm slice thickness. A consensus readout of the iodium-enhanced CTPAs by both radiologists served as reference standard. Gadolinium-enhanced CTPAs were evaluated independently by two experienced radiologists, and differences in detection rate between both contrast agents were assessed on a per embolus basis using the Wilcoxon signed-rank test. Interobserver agreement was determined by calculation of қ values. PE was diagnosed independently by both readers in all five pigs by the use of gadolinium-enhanced CTPA. Out of 60 pulmonary emboli detected in the iodine-enhanced scans, 47 (78.3%; reader 1) and 44 (62.8%; reader 2) emboli were detected by the use of gadolinium. All 13 (100%) emboli in lobar arteries (by both readers) and 26 (reader 1) and 25 (reader 2) out of 27 emboli (96.3% and 92.6%) in segmental arteries were detected by the use of the gadolinium-enhanced CTPA. In subsegmental arteries, only 8 (40%; reader 1) and 6 (30%; reader 2) out of 20 emboli were detected by the gadolinium-enhanced CTPA. By comparing both scans on a per vessel basis (Wilcoxon test), Gd-enhanced CTPA was significantly inferior in emboli detection on subsegmental level (P < 0.0001). The interobserver agreement was excellent on lobar and segmental level (қ = 1.0 and 0.93, respectively), whereas readers only reached moderate agreement for PE evaluation on subsegmental level (қ = 0.56). Compared to conventional CTPA with iodinated contrast media, gadolinium-based contrast agents achieve an equivalent diagnostic accuracy in detection of PE down to segmental level. Gadolinium-enhanced CTPA may be considered as an alternative for the diagnostic workup of acute pulmonary embolism in patients with contraindications to iodinated contrast agents.

Clinical outcomes in patients with isolated subsegmental pulmonary emboli diagnosed by multidetector CT pulmonary angiography

Introduction CT Pulmonary Angiography has been shown to be equivalent to Ventilation/ Perfusion scanning in 3-month outcome studies, but it detects more pulmonary emboli. Isolated subsegmental pulmonary emboli are thought to account for some of the increase in diagnosis, but it is not known whether these emboli represent a harbinger for future thromboembolic events. The objective of this study was to determine the 3-month clinical outcomes of a cohort of patients diagnosed with isolated subsegmental pulmonary emboli. Materials and Methods Review of 10,453 consecutive CTPA radiology reports over 74-month period since the implementation of Multidetector CT Pulmonary Angiography identified a cohort of 93 patients found to have acute pulmonary embolism isolated to subsegmental pulmonary arteries without other evidence of deep venous thrombosis at one institution. The study measured 3-month clinical outcomes (anticoagulation use, recurrence, death, hemorrhage) determined by review of records and telephone interviews with physicians. Results Seventy-one patients (76%) were treated with anticoagulation and/or IVC filter, while 22 (24%) were observed without therapy. One patient (1/93, 1.05%; 95% CI: 0-6.6%) who was treated with anticoagulants and a vena caval filter had a recurrent subsegmental pulmonary embolus. No patients died of pulmonary embolism. There were 8 hemorrhages, including 5 (5.3%) major hemorrhages without any hemorrhage-related mortality. Conclusions Patients diagnosed with isolated subsegmental pulmonary emboli have favorable 3-month outcomes. Short-term prognosis for recurrent thromboembolism may be lower than the risk of adverse events with anticoagulation in patients at high risk of hemorrhage.

Multiple Distal Pulmonary Arterial Thromboses Revealed by Lung Scintigraphy in a Patient With Homocystinuria and Normal Multidetector CT Pulmonary Angiography

Multiple Distal Pulmonary Arterial Thromboses Revealed by Lung Scintigraphy in a Patient With Homocystinuria and Normal Multidetector CT Pulmonary Angiography

Multidetector CT pulmonary angiography features of pulmonary embolus

Pulmonary embolism (PE) is a life-threatening condition. Multidetector CT pulmonary angiography is currently the imaging method of choice for the detection of PE. The aim of this pictorial essay is to review the appearances of PE on multidetector CT pulmonary angiography, including signs that differentiate acute and chronic PE and markers of severity. The features of a non-diagnostic study and pitfalls leading to a false-positive or false-negative study are presented.

Ventilation-Perfusion Scintigraphy Is More Sensitive than Multidetector CTPA in Detecting Chronic Thromboembolic Pulmonary Disease as a Treatable Cause of Pulmonary Hypertension

Pulmonary hypertension (PH) is a progressive disease with a poor prognosis. Identifying chronic thromboembolic pulmonary disease as a cause of PH has major clinical implications as these patients could be potentially offered a surgical cure. Ventilation-perfusion (V/Q) scintigraphy has a high sensitivity to detect embolic disease but its value has been challenged with the emergence of multidetector CT pulmonary angiography (CTPA). We compared the value of V/Q scintigraphy with CTPA in detecting chronic thromboembolic pulmonary disease. We retrospectively reviewed the results of V/Q scintigraphy and CTPA performed on patients who had been referred to the Pulmonary Hypertension Service at Hammersmith Hospital between 2000 and 2005. A total of 227 patients (85 males, 142 females; age range, 18-81 y; mean age, 42 y) had all tests done at Hammersmith Hospital and were included in the study. Interpretation of scans was according to the modified PIOPED (Prospective Investigation of Pulmonary Embolism Diagnosis) criteria. CTPA was considered as suggestive of chronic thromboembolic pulmonary disease if it showed visualization of the thrombus or webs, recanalization, perfusion abnormalities, stenosis, or strictures. Standard pulmonary angiography was performed via femoral approach. In 90% of the cases, CTPA and V/Q scintigraphy were performed within 10 d. Seventy-eight patients (group A) had a final diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH) and 149 (group B) had non-CTEPH etiology. Among group A, V/Q scintigraphy was reported as high probability in 75 patients, intermediate probability in 1 patient, and low probability in 2 patients. CTPA was positive in 40 patients and negative in 38 patients. Among group B, V/Q scintigraphy was reported as low probability in 134, intermediate probability in 7, and high probability in 8 patients. CTPA was negative in 148 patients and false-positive in 1 patient. Statistical analysis showed V/Q scintigraphy to have a sensitivity of 96%-97.4% and a specificity of 90%-95%. CTPA showed a sensitivity of 51% and a specificity of 99%. Our results demonstrate that V/Q scintigraphy has a higher sensitivity than CTPA in detecting CTEPH as a potential curable cause of PH.

Correlated study of direct signs of pulmonary embolism in multi-detector CTPA and the effect of thrombolytic therapy

目的 探讨多层螺旋CT肺血管造影(MDCTPA)中肺动脉栓塞(PE)直接征象与内科溶栓治疗效果的联系.方法对比分析28例PE患者于溶栓前后MDCTPA的影像表现,依据MDCTPA表现具体分型为:Ⅰ型:管腔中心充盈缺损.Ⅱ型:附壁充盈缺损并凸向腔内.Ⅲ型:附壁充盈缺损并凹向腔内.Ⅳ型:血管分支没有增强.结果 28例PE影像资料中,受累肺动脉共计93支,可分析的受累肺动脉分支(2～4级)共74支.统计提示Ⅲ型栓塞表现的内科溶栓抗凝治疗效果(23%,5/22支)显著差于Ⅰ型(95%,19/20支)与Ⅱ型(77%,20/26支),差异有显著性意义(χ2值分别为22.344和14.025 ,P值均 P<0.01).结论 MDCTPA对肺动脉栓塞影像表现的精细显示,能够对内科溶栓抗凝治疗效果进行预测,有助于制定临床治疗方案。