CT Obstruction Index Research Articles

Lipoprotein (a) is not associated with thrombus burden derived from CT pulmonary angiography in patients with acute pulmonary embolism

Lipoprotein (a) [Lp(a)] is suspected to have antifibrinolytic effects, however, its relevance for the severity of venous thromboembolic events remains unclear. We studied the association of Lp(a) levels with thrombus load in pulmonary embolism (PE). 90 patients (40% female, median age 70 [56–79] years) at our tertiary care hospital with a diagnosis of acute PE, available Lp(a) levels and CT pulmonary angiography (CT-PA) performed between April 2017 and December 2019 were included. All CT-PA scans were reanalyzed and thrombus load was determined via Qanadli CT obstruction index (CTOI) and most proximal thrombus location. Median Lp(a) levels were 11.4 [9.3–29.1] mg/dL, median D-dimer levels were 4.6 [2.1–9.8] mg/L, median CTOI was 23 [8–50], central PE was present in 27 (30%) patients. Lp(a) did not correlate with CTOI (r = 0.02, p = 0.922) and was not associated with thrombus location (p = 0.369). CTOI significantly correlated with D-dimer (r = 0.43, p < 0.001) and right to left ventricular diameter ratio (r=-0.49, p = < 0.001). Our findings showed that Lp(a) is not associated with thrombus burden in PE, which suggests that a relevant effect of Lp(a) on the extent of venous thromboembolism is unlikely.

Optional therapeutic management of intermediate-risk pulmonary embolism patients

Background: Few studies have evaluated the thrombolytic treatment in patients with intermediate-high risk pulmonary embolism, making this study more valuable. Material and methods: It was a prospective, non-randomized, open-label, single-center study. Eligible patients at the age of 18 or older with an acute pulmonary embolism (PE) confirmed by CT pulmonary angiography with onset until 14 day and signs of right ventricular (RV) overload on echocardiography took part in the study. Pulmonary Arterial CT Obstruction Index Rate (PACTOIR) was used to define the localization and the expansion zone of thromboembolism. This study included 18 patients with intermediate risk and acute submassive pulmonary thromboembolism. In thrombolysis (TT) group (n=9) were used 50 mg of tissue-plasminogen activator (t-PA) administered in infusion as 0.4 mg/h for 2 hours. In the standard anticoagulation group, unfractioned heparin (UFH) was administered as a bolus of 70 units/kg or a maximum of 5000 units, followed by continuous infusion at an initial rate of 16 units/kg or a maximum of 1000 units/h. Results: The mean age for TT group was 69 vs 63 for the UFH group. PACTOIR was 100% in 3 patients in the half-dose rt-PA group and in 2 patients in the UFH group. RV/LV diameter ratio decreased from baseline to 48 h post-procedure (1.55 vs. 1.13; mean difference, -0.42; p &lt; 0.0001). Mean pulmonary artery systolic pressure was 55 mm Hg in both groups (p &lt; 0.05), with 53 [43–60] in TT group vs. 41.5 [37–45] mmHg in UFH group, P&lt;0.05. Also, RV/ LV ratio and systolic PAP decreased significantly in both groups. Severe bleeding with a need in red blood cell transfusion was seen in 0.11% (1 patient) in the TT group vs 0 in UFH group. The hospitalization length of stay was significantly shorter in the TT group (3.8±1.8, p &lt; 0.05). The rate of secondary endpoints was significantly higher in the UFH group with a high rate of pulmonary hypertension (0 vs. 19%, p=0.003). Conclusions: Half-dose thrombolytic therapy in patients diagnosed with submassive pulmonary embolism significantly reduced death and hemodynamic decompensation in the first 7 days compared to anticoagulant therapy only. With all that being said, it can be concluded that patients with high-intermediate risk PE could benefit from reduced-dose TT.

Continuous mechanical aspiration thrombectomy performs equally well in main versus branch pulmonary emboli: A subgroup analysis of the EXTRACT-PE trial.

The EXTRACT-PE trial evaluated the safety and performance of the Indigo Aspiration System (PenumbraInc.) with an 8F continuous mechanical aspiration thrombectomy system for the treatment of pulmonary embolism (PE). This subgroup analysis evaluates performance outcomes of patients with main pulmonary artery (PA) emboli versus discrete unilateral or bilateral PA emboli without main PA involvement. The EXTRACT-PE trial was a prospective, single-arm, multicenter trial that enrolled 119 patients with acute submassive PE. Emboli location was collected at the time of enrollment, CT obstruction was measured and assessed by a Core Lab, and patients were grouped on whether emboli involved the main PA (with or without branch vessels) or not (branch vessels alone). Procedural device time, changes in the right ventricle to left ventricle (RV/LV) ratio, and systolic PA pressure from pre-and posttreatment were compared between the two groups. Out of the 119 patients enrolled, 118 had core lab-assessed clot locations. Forty-five(38.1%) had emboli that involved the main PA and 73 (61.9%) had only branch emboli. No significant difference was observed between these groups for 30-day mortality, procedural device time, changes in RV/LV ratio, reduction in CT Obstruction Index, or for systolic PA pressure from pre-and posttreatment. The mean absolute reduction in clot burden was significant in both groups. Continuous mechanical aspiration thrombectomy with the 8F Indigo Aspiration System was effective at improving clinical outcomes for submassive PE patients regardless of emboli location, and clot burden was significantly reduced in both groups.

Can vitamin D level be a marker for predicting risk in pulmonary thromboembolism? Comparative evaluation with pulmonary embolism severity index and CT angiography obstruction index

Background/Aim: Venous thromboembolism is a pathological process that is among the leading causes of hospital mortality, and many studies showed that vitamin D receptors have a role in thrombosis. This study aimed to investigate the effect of 25(OH)D deficiency on pulmonary thromboembolism and evaluate the pulmonary embolism severity index (PESI). Methods: Eighty-one patients over 18 years of age who underwent CT angiography with a pre-diagnosis of pulmonary embolism were included in this case-control study. Groups 1 and 2 consisted of 45 patients with pulmonary embolism (PE), and 36 patients without pulmonary embolism, respectively. The PE patients were divided into five groups in terms of age, gender, fever, systolic blood pressure, heart rate, respiratory rate, oxygen saturation, history of chronic lung disease and heart failure, mental status, and malignancy to calculate the PESI score. Classes 1 and 2 were classified as low-risk, and Classes 3, 4, and 5 as high-risk. The CT obstruction index (CTOI) was calculated in patients with pulmonary embolism. Vitamin D levels were noted. Results: No significant difference was observed between the groups in terms of age, gender, and body mass index values (P>0.05). 25(OH)D level was significantly lower in the pulmonary embolism group (7.2(3.3) vs. 8.7(7.0), P=0.028). The CTOI was significantly higher in the high-risk patient group (P=0.019). Conclusions: The evaluation of 25(OH)D levels may be beneficial in determining the risk of thromboembolism.

Importance of computed tomography pulmonary angiography for predict 30-day mortality in acute pulmonary embolism patients

ObjectiveThe purpose of the present study was to assess the implications of different parameters of computed tomography pulmonary angiography (CTPA) to predict 30-day mortality in acute pulmonary embolism (APE) patients. Material and MethodPatients who had clinical suspicion of APE and underwent CTPA were recruited in a retrospective cohort study. The findings of the CTPA included the parameters of right ventricular dysfunction (RVD), the severity of obstruction to the pulmonary artery by CT obstruction index, and the ratio of pulmonary trunk diameter and aorta. The endpoint of the study was established as the 30-day mortality associated with APE. ResultsA total of 238 patients with a confirmed APE diagnosis with CTPA were included in the study; 26 (10.9 %) of those patients died within 30 days. In patients with cancer and the Pulmonary Embolism Severity Index (PESI) class 5, the mortality rate was significantly higher. Compared with survivors, the mean CT obstruction index in the non-survivor group was significantly higher (p < 0.001). Higher mortality was associated with all RVD parameters identified by CTPA, such as the RV/LV ratio (p < 0.001), interventricular septum deviation grade 3 (p < 0.001), increased RV diameter (p < 0.001), and IVC contrast reflux (p < 0.001). The highest adjusted odds ratio was RV diameter at 1.094, followed by PESI and the CT obstruction index at 1.040. ConclusionCTPA-detected RVD parameters and CT obstruction index can predict a 30-day mortality rate in APE patients and be used for risk stratification. In APE patients, the RV diameter of 53 mm or greater and the CT obstruction index >70% is associated with increased 30-day mortality.

Impact of higher detection rate of residual pulmonary thromboemboli one-year after acute pulmonary embolism: modified CT scan imaging method with modified CT obstruction index

Abstract Background Recently, post pulmonary embolism (PE) syndrome or chronic thromboembolic disease after acute PE, has been recognized as important long-term complications. Furthermore, patients may develop with chronic thromboembolic pulmonary hypertension. Purpose We aimed to evaluate the frequency of residual pulmonary thromboemboli after acute PE by using our “higher”-resolution CT scan imaging method to detect residual thromboemboli down to sub-segmental pulmonary arteries. Methods This study was a prospective multi-center observational study. We enrolled consecutive 34 patients with acute symptomatic PE whose informed consent was obtained, and followed up for one year. One year after the onset of acute PE, patients were referred to our hospital and multiple examination including CT scan, 6-minute walk test (6MWT), questionnaire of SF-36, echocardiography and laboratory testing were performed. Additionally, we have modified the CT obstruction index (CTOI) to quantitatively evaluate the thromboemboli down to sub-segmental pulmonary arteries. Results Mean age was 60.5±15.8 years, and 56% were male. No patient was categorized as low recurrent VTE risk which was caused by transient factors, one patient was associated with active cancer, and 12% had known thrombophilia. In 85% of the patients, this onset was the first obvious episode of PE. At diagnosis, elevated B-type natriuretic peptide (BNP) (≥100 pg/ml) or N-terminal (NT)-proBNP (≥500 pg/ml) was observed in 45% of the patients. Median tricuspid regurgitation peak gradient (TRPG) by echocardiography was 30.9 (19.3–50.1) mmHg. Among all, 35% of the patients received single-drug approach with DOACs. At discharge, all of the patients except two were treated with DOACs. One year after the onset, 21% of the patient were in NYHA II and others were in NYHA I. It was notable that pulmonary thromboemboli was detected by our CT scan in 76% of the patients. Modified CTOI was median 11.9 (1.8–24.4) % as shown in the figure. In multiple regression analysis, TRPG at diagnosis and BNP at one month were significantly associated with mCTOI (β=0.536, p=0.002 and β=−0.482, p=0.003, respectively). Additionally, lowest SpO2 during 6MWT after one year from the onset, tended to inversely associate with mCTOI (β=−0.341, p=0.052). Conclusions Using our modified CT scan imaging method and modified CTOI, residual pulmonary thromboemboli was able to be detected more frequently than the previous studies. Residual pulmonary thromboemboli could be one of the cause of the post PE syndrome and lead to exercise-induced desaturation. Figures Funding Acknowledgement Type of funding source: None

Dual-Energy CT Pulmonary Angiography (DECTPA) Quantifies Vasculopathy in Severe COVID-19 Pneumonia.

BackgroundThe role of dual energy computed tomographic pulmonary angiography (DECTPA) in revealing vasculopathy in coronavirus disease 2019 (COVID-19) has not been fully explored.PurposeTo evaluate the relationship between DECTPA and disease duration, right ventricular dysfunction (RVD), lung compliance, D-dimer and obstruction index in COVID-19 pneumonia.Materials and MethodsThis institutional review board approved this retrospective study, and waived the informed consent requirement. Between March-May 2020, 27 consecutive ventilated patients with severe COVID-19 pneumonia underwent DECTPA to diagnose pulmonary thrombus (PT); 11 underwent surveillance DECTPA 14 ±11.6 days later. Qualitative and quantitative analysis of perfused blood volume (PBV) maps recorded: i) perfusion defect ‘pattern’ (wedge-shaped, mottled or amorphous), ii) presence of PT and CT obstruction index (CTOI) and iii) PBV relative to pulmonary artery enhancement (PBV/PAenh); PBV/PAenh was also compared with seven healthy volunteers and correlated with D-Dimer and CTOI.ResultsAmorphous (n=21), mottled (n=4), and wedge-shaped (n=2) perfusion defects were observed (M=20; mean age=56 ±8.7 years). Mean extent of perfusion defects=36.1%±17.2. Acute PT was present in 11/27(40.7%) patients. Only wedge-shaped defects corresponded with PT (2/27, 7.4%). Mean CTOI was 2.6±5.4 out of 40. PBV/PAenh (18.2 ±4.2%) was lower than in healthy volunteers (27 ±13.9%, p = 0.002). PBV/PAenh correlated with disease duration (β = 0.13, p = 0.04), and inversely correlated with RVD (β = -7.2, p = 0.001), persisting after controlling for confounders. There were no linkages between PBV/PAenh and D-dimer or CTOI.ConclusionPerfusion defects and decreased PBV/PAenh are prevalent in severe COVID-19 pneumonia. PBV/PAenh correlates with disease duration and inversely correlates with RVD. PBV/PAenh may be an important marker of vasculopathy in severe COVID-19 pneumonia even in the absence of arterial thrombus.

CT Pulmonary Angiography for Risk Stratification of Patients with Nonmassive Acute Pulmonary Embolism.

To investigate the prognostic value of an integrative approach combining clinical variables and the Qanadli CT obstruction index (CTOI) in patients with nonmassive acute pulmonary embolism (PE). This retrospective study included 705 consecutive patients (mean age, 63 years; range, 18-95 years) with proven PE. Clot burden was quantified using the CTOI, which reflects the ratio of fully or partially obstructed pulmonary arteries to normal arteries. Patients were subdivided into two groups according to the presence (group A) or absence (group B) of preexisting cardiopulmonary disease. Thirty-day and 3-month mortality was evaluated. CTOI thresholds of 20% and 40% were used to stratify patients regarding outcome (low, intermediate, and high risk). The predictive value of CTOI was assessed through logistic regression analysis. Analysis included 690 patients (mean age, 63.3 years ± 18 [standard deviation]) with complete follow-up data: 247 (36%) in group A and 443 (64%) in group B. The mean CTOI was 23% ± 19, 30-day mortality was 9.7%, and 3-month mortality was 11.6%. Three-month mortality was higher in group A than in group B (17.8% and 8.1%, respectively; P = .001). Within group B, CTOI predicted outcome and allowed stratification: significantly higher mortality with CTOI greater than 40% (P < .001) and lower mortality with CTOI less than 20% (P = .05). CTOI did not predict outcome in group A. Age was an independent mortality risk factor (P ≤ .04). CTOI predicted outcome in this cohort of patients with PE and no cardiopulmonary disease, and it may provide a simple single-examination-based approach for risk stratification in this subset of patients.© RSNA, 2020See also the commentary by Kay and Abbara in this issue.

Serial imaging after pulmonary embolism and correlation with functional limitation at 12 months: Results of the ELOPE Study

Unlabelled Box IntroductionRisk factors for exercise limitation after acute pulmonary embolism (PE) are unknown. As a planned sub‐study of the prospective, multicenter ELOPE (Evaluation of Long‐term Outcomes after PE) Study, we aimed to describe the results of serial imaging by computed tomography pulmonary angiography (CTPA) and perfusion scan during 1 year after a first episode of acute pulmonary embolism, and to assess the association between imaging parameters and exercise limitation at 1 year. MethodsIn a prospective cohort study, 100 patients were recruited between June 2010 and February 2013 at five Canadian university–affiliated hospitals. CT pulmonary angiography was performed at baseline and 12 months, perfusion scan at 6 and 12 months, and cardio‐pulmonary exercise testing at 1 and 12 months. Imaging parameters included: on CT pulmonary angiography, CT obstruction index (CTO) (% clot burden in the pulmonary vasculature), and on perfusion scan, pulmonary vascular obstruction (PVO) (% perfusion defect). Abnormal cardio‐pulmonary exercise test (primary outcome) was defined as percent of predicted peak oxygen uptake (VO2) <80%. ResultsMean (median; SD) CT obstruction index was 28.1% (27.5%; 18.3%) at baseline, 1.2% (0%; 4.3%) at 12 months. Mean (median; SD) pulmonary vascular obstruction was 6.0% (0%; 9.6%) at 6 months, 5.6% (0%; 9.8%) at 12 months. Eighty‐six patients had exercise testing at 12 months, and 46.5% had VO2 < 80% predicted. Mean (median; SD) CT obstruction index at 1 year was similar in patients with percent‐predicted VO2 peak <80% vs >80% on 1‐year cardio‐pulmonary exercise testing (1.4% [0%; 5.7%] vs 1.0% [0%; 2.4%]; P=.70). Mean (SD) pulmonary vascular obstruction at 6 and at 12 months was similar in patients with percent‐predicted VO2 peak <80% vs >80% (6 months: 5.9% [0%; 10.4%] vs 6.2% [4.5%; 9.0%]; P=.91; 12 months: 5.1% [0%; 10.2%] vs 6.0% [0%; 9.7%]; P=.71). ConclusionsImaging findings after pulmonary embolism did not predict exercise limitation. Residual thrombus does not appear to explain long‐term functional limitation after pulmonary embolism.

Histogram-pattern analysis of the lung perfused blood volume for assessment of pulmonary thromboembolism.

We aimed to evaluate the usefulness of histograms of lung perfused blood volume (HLPBV) based on the presence of pulmonary thromboembolism (PTE) and the pulmonary embolic burden. A total of 168 patients (55 males; mean age, 62.9 years) underwent contrast-enhanced dual-energy computed tomography (DECT) between January 1 2012 and October 31 2014. Initial DECT images were three-dimensionally reconstructed, and the HLPBV patterns were divided into three types, including the symmetric type (131 patients, 78.0%), gradual type (25 patients, 14.9%), and asymmetric type (12 patients, 7.1%). Acute PTE was diagnosed in all 12 patients with asymmetric type (100%), 19 of the 25 patients with gradual type (76%) and 24 of the 131 patients with symmetric type (18.3%). HLPBV pattern exhibited correlations with the right/left ventricular diameter ratio (r=0.36, P = 0.007) and CT obstruction index (r=0.63, P < 0.001) in patients with PTEs. When the gradual and asymmetric types were regarded as positive for PTE, the specificity, positive predictive value, negative predictive value, and accuracy were 92.9%, 83.8%, 87.6%, and 81.0%, respectively. Histogram-pattern analysis using DECT might be a useful application to diagnose PTE.

Assessment of Pulmonary Embolism Severity and Scoring Using Multi Slice CT in Correlation with Clinical Presentation and Echocardiography

Aim of the work: The aim of this study is to evaluate the correlation between pulmonary embolism severity and scoring obtained using multi slice CT (MSCT) and the clinical presentations and echocardiography in patients with pulmonary embolism (PE). Patients and method: this study was carried out in the Radiology Department of Ain Shams University Hospitals. 21 patients with PE. The CT obstruction index (OI) using Qanadli score and the RV/LV diameter Right ventricle dysfunction ratio (RVD-ratio) using the four-chamber view of the heart were calculated for all patients. The cut-off for the OI to detect RVD was constructed using ROC curve. They were 13 (61.9%) females and 8 (38.1%) males. Their age was ranged from 22 -83 years old. Results: Dyspnea and RVD (RVD-ratio >1) were significantly more common in patients with severe pulmonary embolism. Regarding the echo findings with PE high Right ventricular systolic pressure (RVSP) was the commonest echo finding among our studied patients. The cutoff point of obstruction index (OI) >15 (Qanadli score >37.5 %) has the highest prediction value of right ventricular dysfunction, indicating that most of the patients with a score of more than 37.5% had RVD that was agreed with echo findings.

Effect of 50 mg alteplase to intermediate-risk pulmonary embolism with right ventricular dysfunction

Objective: To investigate the effect of 50 mg alteplase to intermediate-risk acute pulmonary embolism (APE) with right ventricular dysfunction. Methods: From May 2011 to May 2015, a total of 73 patients with intermediate-risk APE, furthermore, right ventricular systolic pressure (RVSP)>40 mmHg and B-type natriuretic peptide (BNP)>100 ng/L, were allocated to receive 50 mg alteplase plus anti-coagulation (thrombolysis group, TG, n=35) or anticoagulation alone (control group CG, n=38) according to their will.Tricuspid annular plane systolic excursion (TAPSE), Right ventricular fractional area change (RVFAC), RVSP, BNP, CT obstruction index (CTOI) were detected at prior treatment, 1st day, 14th day, 3rd month, 6th month. The adverse events consisting of hemodynamic decompensation (within 14 days), mortality, bleeding, recurrent pulmonary embolism (PE), RVSP>40 mmHg (at 6th month) were recorded. Results: At prior treatment, TAPSE, RVFAC, RVSP, BNP and CTOI between TG and CG were (10.9±1.4) vs (11.4±1.2) mm, (27.8±3.9)% vs (28.1±4.1)%, (55.6±7.9) vs (54.6±8.4) mmHg, (491±76) vs (482±71) ng/L and (23.4±4.2)% vs (23.7±4.5)%. There was not statistical difference between two groups (all P>0.05). From 1st to 14th day, these indexes had better and faster improvement in TG than CG. At 6th month, TAPSE, RVFAC, RVSP and CTOI between two groups were (17.5±1.3) vs (15.4±1.1) mm, (49.4±3.9)% vs (46.0±2.8)%, (15.8±2.2) vs (17.8±4.2) mmHg, and (1.7±1.6)% vs (4.0±3.0)% (all P<0.05), BNP was (66±13) vs (71±15) ng/L (P>0.05). From prior treatment to 6th month, the tendency of variation of these index in TG was better than CG (P<0.05). From prior treatment to 14th day, 3 cases of hemodynamic decompensation occurred in CG, 0 case in TG.During treatment, there were not cases of death and major bleeding. At 6th month, there were 4 cases of RVSP>40 mmHg in CG, while 0 case in TG (P=0.048). Conclusion: 50 mg alteplase can reduce the thrombus in pulmonary artery, improve right ventricular function quickly, and decrease the risk of elevated RVSP in the long term, for the patients with intermediate-risk APE.

Evaluation of acute pulmonary embolism by sixty-four slice multidetector CT angiography: Correlation between obstruction index, right ventricular dysfunction and clinical presentation

IntroductionMDCT pulmonary angiography is the method of choice for the detection of pulmonary embolism (PE). The severity of PE as estimated by the obstruction index (OI) and right ventricular dysfunction (RVD) can be evaluated with MDCT. ObjectiveTo investigate the correlation between the OI, RVD and clinical presentation in patients with acute PE. MethodsAmong 70 patients with suspected PE, 35 patients proved to have PE with MDCT. The CT OI and the RV/LV diameter (RVD-ratio) using the four-chamber view of the heart were calculated for PE patients. The cut-off for the OI to detect RVD was constructed using ROC curve. ResultsDyspnea and RVD (RVD-ratio >1) were significantly more common in patients with central pulmonary emboli. The mean OI (35%±19%) was significantly higher in patients with dyspnea, tachycardia and obesity. A positive correlation was found between the OI and both the CT pulmonary artery diameter (r=0.66, p<0.001) and the RVD-ratio (r=0.628, p<0.001). The mean OI was significantly higher in patients with RVD (p<0.001). A CT OI>43% identified more than 90% of patients with RVD (area under the curve on ROC analysis: 0.825; p<0.001). ConclusionThe mean OI correlated linearly with PA diameter and RVD-ratio. OI>43% proved to be an independent predictor of RVD.

Can Pulmonary Arterial CT Obstruction Index Rate Predict Right Ventricular Dilatation in Pulmonary Thromboembolism?

Can Pulmonary Arterial CT Obstruction Index Rate Predict Right Ventricular Dilatation in Pulmonary Thromboembolism?

The effect of the section thickness used for 2- and 3-dimensional quantification of dual-energy perfusion computed tomography.

To retrospectively investigate the effect of the section thickness used for quantifying dual-energy perfusion computed tomography (DEpCT) during 2- and 3-dimensional evaluation. Sixty-six patients (22 males and 44 females; mean age, 59.3 years) suspected of having an acute pulmonary embolism underwent DEpCT, and 15patients were diagnosed to have intrapulmonary clots (IPCs). Two-dimensional DEpCT images were reconstructed into various section thicknesses from 1 to 10 mm at the main pulmonary artery, and the ratios of the low attenuation area (LAA) ranging from 1 to 5 HU (%LAA5) and 10 HU (%LAA10) on DEpCT were compared with the relative areas of the lung with attenuation coefficients lower than -950 HU (RA-950) using the lung CT images of each section thickness. Three-dimensional values of DEpCT were reconstructed with 3 different section thicknesses (1, 3, and 10 mm) and were analyzed for the presence of IPC burden using the factors suggesting IPC burden, including the right/left ventricular diameter ratio and CT obstruction index. The mean attenuation and image noise were decreased as the section thickness increased. In the 2-dimensional analysis, the %LAA5 and %LAA10 had the smallest value at 1-mm section, and DEpCT with thinner sections had a correlation with the RA-950 (r = 0.22-0.23, P < 0.05). The 3-dimensional values of DEpCT reconstructed with a 1- or 3-mm section thickness had a correlation with the CT obstruction index (r = 0.52-0.59, P < 0.05) and right/left ventricular diameter ratio (r = 0.60-0.68, P < 0.01). The thinner images should be used for 2- and 3-dimensional quantification of DEpCT.

What does radiologist mean when they report a pulmonary embolism as central or segmentary?

Background: Radiologists often report CT pulmonary angiography as central or segmentary pulmonary embolism (PE). However, this system offers scanty information about the severity of the episode of PE. Patients and methods: We studied consecutive patients diagnosed with PE by means of CT angiography. Of every patient blood arterial gases, troponin I, NT-pro-BNP, systolic blood pressure, heart and respiratory rate, and shock index all of them were measured on diagnosis. The thrombotic burden was evaluated with formula for the CT obstruction index.

Evaluation of computed tomography obstruction index in guiding therapeutic decisions and monitoring percutanous catheter fragmentation in massive pulmonary embolism

In the present study, we evaluated computed tomography pulmonary angiography (CTPA) in guiding therapeutic decisions and monitoring patients undergoing percutaneous catheter fragmentation in acute massive pulmonary embolism. From Jan 2003 to Dec 2009, 35 patients were diagnosed with acute massive pulmonary embolism by CTPA (T0) and treated with percutaneous catheter fragmentation. The severity was assessed by CT obstruction index (Qanadli index) and compared with Miller index. CTPA, oxygen saturation (SaO 2) and pulmonary artery pressure were performed as follow-up index. The mean percentage of Qanadli index was (55±13)% (range, 40%-75%), and Miller index was (62±15)% (range, 45%-85%). Correlations between them were statistically significant ( r = 0.867, P < 0.0001). The Qanadli index showed significant reduction [T0: (55±13)%; T1: (12±10)%; P < 0.001] in 33 patients. Significant correlation was observed between the Qanadli index, SaO 2 ( r = 0.934), and pulmonary artery pressure ( r = 0.813). The Qanadli index provides an accurate method for distinguishing massive pulmonary embolism from sub-massive pulmonary embolism. It can be used to determine therapeutic options and monitor clinical outcomes.

Association of deep vein thrombosis type with clinical phenotype of chronic thromboembolic pulmonary hypertension

BackgroundChronic thromboembolic pulmonary hypertension (CTEPH) has been considered to be caused by single or recurrent pulmonary embolism (PE) arising from deep vein thrombosis (DVT). In Japan, female predominance and association of HLA-B*5201 with CTEPH unrelated to DVT were reported. In acute PE residual proximal DVT is associated with larger obstruction of pulmonary arteries. However, it remains uncertain whether DVT and the type of DVT are associated with clinical phenotype of CTEPH. PurposeTo clarify the association of DVT and DVT type with clinical phenotype of CTEPH. MethodsAmong 98 consecutive patients who underwent 16 or 64-slice multidetector CT angiography and indirect venography, 91 patients (66% female, age: 56±3years) with adequate images were enrolled. The associations of DVT and DVT type with pulmonary hemodynamics, CT obstruction index and other clinical parameters were analyzed. ResultsDVT was found in 45 patients (49.5%) (distal: 12, proximal: 33), and was significantly associated with male gender and recurrent type. Furthermore, it was more frequent in HLA-B*5201-negative, and d-dimer positive patients. Compared with distal DVT, proximal DVT was associated with male gender, larger CT obstruction index (48.6±13.0 vs. 34.1±13.2%, p=0.004), and higher mean pulmonary arterial pressure (48.2±12.8 vs. 40.8±7.9mmHg, p=0.03). Proximal DVT was significantly associated with the central type of CTEPH only in HLA-B*5201-negative patients. ConclusionsThe existence and type of DVT were associated with clinical phenotype of CTEPH, and proximal DVT might contribute to the central type of CTEPH in only HLA-B*5201-negative patients.

Massive Pulmonary Emboli and CT Pulmonary Angiography

Background: Massive pulmonary embolism (PE) is a devastating form of PE which usually results in acute right ventricular failure and death within 1–2 h. Objectives: To retrospectively assess pulmonary vascular, cardiac, pleural, and parenchymal findings on CT pulmonary angiography (CTPA) in patients with a diagnosis of massive PE (systolic blood pressure <90 mm Hg, syncope and/or shock). Methods: In 33 consecutive patients with proven massive PE, hemodynamic severity was assessed by the extent of right ventricular dysfunction (RVD); diameter of the main pulmonary artery; the shape of the interventricular septum; and the extent of obstruction to the pulmonary arterial circulation (CT obstruction index). Results: Central pulmonary arteries were embolized in all patients. RVD was detected in all patients (94% of them had severe RVD); the diameter of the main pulmonary artery was wider than normal in 76% of the patients; the shape of the interventricular septum was abnormal in all patients, and the CT obstruction index was higher than or equal to 50% in 85% of the patients. Wedge-shaped pleural-based consolidation was the most common parenchymal abnormality (36%). Pleural effusions were seen in 26 patients (79%). Twenty-eight patients were alive, and only the use of thrombolytic therapy was found to be statistically significant. Conclusions: In patients with acute massive PE, embolization of the central pulmonary arteries, RVD and displacement of the interventricular septum are commonly seen with CTPA. A CT obstruction index of >50% is commonly observed in massive PE. There was no association between CTPA findings and survival.

Acute Pulmonary Embolism: Correlation of CT Pulmonary Artery Obstruction Index with Blood Gas Values

The purpose of our study was to investigate the relation between the pulmonary artery obstruction index assessed with helical CT and impairment in blood gases in patients with acute pulmonary embolism. Helical CT pulmonary angiography was performed in 78 patients who were suspected of having acute pulmonary embolism and selected as being free of underlying cardiopulmonary disease. Findings consistent with acute pulmonary embolism were observed in 34 patients. The severity was assessed by the pulmonary artery obstruction index, defined as Sigma (n x d), where n is the number of segmental arteries occluded and d is the degree of obstruction. Spearman's rank correlation coefficients were used to assess the correlation between the index of arterial obstruction and arterial partial pressure of oxygen (Pao(2)); alveolar-arterial difference in partial pressure of oxygen (Pao(2)-Pao(2)); arterial partial pressure of carbon dioxide (Paco(2)); and arterial oxygen saturation (Sao(2)). The statistical difference of the arterial blood gas values between the two groups of patients (those with and those without pulmonary embolism) was evaluated using the Mann-Whitney U test. Blood gases were comparatively evaluated below and above different index values (from 40% to 70%) and different Paco(2) values (25, 30, and 35 mm Hg) as possible indexes of embolism severity using the same test. The level of significance was set at 95% (p = 0.05). The values of Pao(2), Sao(2), and Paco(2) were significantly lower (p = 0.024, p = 0.0062, and p = 0.000075, respectively) and the values of Pao(2)-Pao(2) were significantly higher (p = 0.0169) in the pulmonary embolism group than in the no-pulmonary-embolism group. A significant correlation was observed between the obstruction index and Pao(2) (r = -0.33, p = 0.05), Paco(2) (r = -0.34, p = 0.05), Pao(2)-Pao(2) (r = 0.39, p = 0.02), and Sao(2) (r = -0.35, p = 0.04). Using cutoff values for the pulmonary artery obstruction index of 40%, 50%, 60%, and 70%, we observed that Paco(2) and Pao(2)-Pao(2) differed significantly between above and below the 40% (p = 0.018 and p = 0.03), 50% (p = 0.0087 and p = 0.029), and 60% (p = 0.005 and p = 0.003) cutoffs. Pao(2) differed significantly for the cutoff values of 60% (p = 0.03) and 70% (p = 0.004). The same was observed for Sao(2) at 60% (p = 0.05) and 70% (p = 0.03). Comparisons for Paco(2) showed that a value of 30 mm Hg significantly separates levels of the pulmonary artery obstruction index (p = 0.002), with 78% sensitivity and 82% specificity indicating a pulmonary artery obstruction index greater than 50%. In patients with acute pulmonary embolism but no other underlying cardiopulmonary disease, the severity of the pulmonary arterial tree obstruction assessed using the CT obstruction index is significantly correlated to the blood gas values. The strongest correlation was observed between the index and the Pao(2)-Pao(2). Furthermore, a Paco(2) value of 30 mm Hg or less is highly suggestive of an obstruction index of more than 50% of the arterial bed.