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Original Research: Pulmonary vascular disease |

Role of 320-Slice CT Imaging in the Diagnostic Workup of Patients With Chronic Thromboembolic Pulmonary Hypertension320-Slice CT Scan in Diagnostic Workup FREE TO VIEW

Toshihiko Sugiura, MD; Nobuhiro Tanabe, MD, PhD, FCCP; Yukiko Matsuura, MD; Ayako Shigeta, MD, PhD; Naoko Kawata, MD, PhD; Takayuki Jujo, MD; Noriyuki Yanagawa, RT; Seiichiro Sakao, MD, PhD; Yasunori Kasahara, MD, PhD, FCCP; Koichiro Tatsumi, MD, PhD, FCCP
Author and Funding Information

From the Department of Respirology, Graduate School of Medicine, Chiba University, Chiba, Japan.

Correspondence to: Toshihiko Sugiura, MD, Department of Respirology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuou-ku Chiba 260-8670, Japan; e-mail: sugiura@js3.so-net.ne.jp


Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.

Funding/Support: This study was partly supported by a grant to the Respiratory Failure Research Group from the Ministry of Health, Labor and Welfare, Japan [No. 23162501 to Dr Tatsumi], and a grant from the Ministry of Education, Culture, Sports, Science and Technology of Japan [No. 22590849 to Dr Tanabe].


Chest. 2013;143(4):1070-1077. doi:10.1378/chest.12-0407
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Background:  Right-sided heart catheterization (RHC) and pulmonary digital subtraction angiography (PDSA) are the standard methods used in diagnosing suspected or definite chronic thromboembolic pulmonary hypertension (CTEPH). We studied the ability of 320-slice CT imaging to detect simultaneously chronic thromboembolic findings in the pulmonary arteries and pulmonary hemodynamics based on the curvature of the interventricular septum (IVS) in CTEPH.

Methods:  Forty-four patients with high clinical suspicion of CTEPH underwent RHC, PDSA, and enhanced double-volume retrospective ECG-gated 320-slice CT scan. We measured the sensitivity and specificity of CT imaging to detect thrombi in the pulmonary arteries compared with PDSA. We also compared IVS bowing (expressed as curvature) measured on the short-axis cine heart image with pulmonary arterial pressure (PAP) obtained by RHC.

Results:  Compared with PDSA, the sensitivity and specificity of CT imaging to detect chronic thromboembolic findings were 97.0% and 97.1% at the main/lobar level and 85.8% and 94.6% at the segmental level, respectively. The correlation coefficients of IVS curvature with systolic PAP and mean PAP were −0.79 (P < .001) and −0.86 (P < .001), respectively.

Conclusions:  The use of 320-slice CT imaging allows for less invasive and simultaneous detection of thrombi and evaluation of pulmonary hemodynamics for the diagnostic work-up of CTEPH.

Figures in this Article

Chronic thromboembolic pulmonary hypertension (CTEPH) is a very severe disease caused by nonresolving thromboemboli in the pulmonary arteries and can potentially be cured by pulmonary endarterectomy (PEA). If left untreated, depending on the extent of the obstruction of the vascular bed and vascular remodeling in the unobstructed distal pulmonary arteries, there may be increased right ventricular afterload and progression of pulmonary hypertension (PH).13

Invasive pulmonary digital subtraction angiography (PDSA) is a standard diagnostic tool used to assess patients with suspected or definite CTEPH both toestablish the diagnosis and to assess operability.3,4 In contrast to PDSA, ventilation/perfusion (V. /Q. ) lung scintigraphy and enhanced helical CT imaging are recommended as primary, less invasive substitutes for vascular imaging.58 In addition, previous studies have shown that contrast multislice CT imaging angiography can be used to evaluate the pulmonary artery and is a less invasive alternative to PDSA for the diagnosis of CTEPH.911 However, CT imaging angiography is less sensitive thanV. /Q.  lung scintigraphy in the diagnosis of CTEPH.5,6

Invasive pulmonary artery pressure (PAP) measurement using right-sided heart catheterization (RHC) is the “gold standard” for the diagnosis of PH.14 Currently, less invasive PAP estimation using transthoracic echocardiography is recommended to screen for PH.12,13 In the presence of increased systolic pressure in the right ventricle (RV), the interventricular septum (IVS) flattens and sometimes even bows leftward into the left ventricle. Earlier studies showed that the IVS curvature on cardiac MRI was well correlated with PAP in patients with PH.14

Recently, because of advances in CT imaging technology, ECG-gated multislice CT scan has been used to image the heart with high spatial and temporal resolution. Taylor et al15 reported the possibility of quantitative evaluation of right ventricular function and morphology using ECG-gated 64-slice CT imaging. The introduction of 320-slice CT scanning affords 16-cm craniocaudal coverage and allows volumetric imaging of the entire heart with only a single gantry rotation.16 In addition, a series of two gantry rotations (double-volume scan) with ECG-gated 320-slice CT scanning can acquire simultaneous images of the pulmonary arteries and the entire heart.

The purpose of this study was to measure the sensitivity and specificity of 320-slice CT imaging to detect chronic thromboembolic findings in the pulmonary arteries and to evaluate the relationship between IVS curvature on 320-slice CT scan and PAP measured by RHC. Our hypothesis was that 320-slice CT imaging can be used for less invasive and simultaneous evaluation of the pulmonary artery and hemodynamics in the diagnostic work-up of patients with CTEPH.

Patients

The study group comprised 44 consecutive patients (28 women; mean age, 59 years; range, 33-78 years) with high clinical suspicion of CTEPH based onV. /Q. lung scintigraphy and transthoracic echocardiography. All patients were enrolled from March 2009 to April 2012 and underwent enhanced retrospective ECG-gated 320-slice CT imaging, RHC, and PDSA. The shortest and longest intervals between CT scan and RHC plus PDSA were 2 days and 2 weeks, respectively. The study was approved by the ethics committee of Chiba University (approval number 826), and written informed consent was obtained from each patient before CT scan, RHC, and PDSA.

320-Slice CT Scan

All CT scans were obtained with retrospective ECG-gated enhanced volume scanning using a 320-slice CT scanner (Aquilion One, Toshiba Medical Systems Engineering Co, Ltd) with a 0.5-mm slice thickness and 0.35 s/rotation. To acquire simultaneous images of the pulmonary arteries and the entire heart, an axial series of two gantry rotations in a cranial-to-caudal direction was performed (double-volume scan). The resulting dual-volume data sets were stitched automatically. Because the most cranial and caudal parts of each volume data set (both 1.6 cm) were not used to create images, the effective scan length was 25.6 cm. The tube voltage was set to 120 kV and the tube current to 580 mA, with tube current dose modulation. Using a mechanical injector (Dual Shot; Nemoto), 100 mL of contrast media (Iomeron 350 mg/mL; Eisai Co, Ltd) was injected at 3.5 mL/s followed by the injection of a saline-contrast media mixture of 40 mL contrast media at 2.0 mL/s and 30 mL saline at 1.5 mL/s. Time-resolved (every 1 s) single-section CT scans were acquired at the level of the bifurcation of the pulmonary artery without a breath hold. Ascending aortic time-resolved attenuation was then measured using the time attenuation evaluation program accessible on the scanner. When the CT scan values in the ascending aorta increased to 200 Hounsfield units, we started the actual examination scan while the subject held his or her breath.

The CT images for a normal work-up used to diagnose pulmonary thrombi were reconstructed at 75% of the R-R interval with 0.5-mm slice thickness at 0.5-mm intervals using a standard algorithm. The CT images were digitally stored and analyzed at a dedicated workstation. Two independent observers interactively analyzed all arteries on two split screens showing axial, coronal, or sagittal views. The two observers were blinded to the subject’s baseline characteristics and RHC results. Final evaluations were achieved by consensus.

Calculation of IVS Curvature on 320-Slice CT Scan

The CT images were reconstructed at every 5% from 0% to 95% of the R-R interval. Then short-axis cine images of the heart were acquired using double-oblique multiplanar reformation. The IVS curvature was measured in the short-axis image plane at the midventricular level (at least one papillary muscle visible). At this level, the cine image with the most deformation of the septum was used for quantification. IVS bowing was quantified by the curvature (defined as 1 divided by the radius of curvature in centimeters), and this was calculated by entering coordinates (x, y) from three different points on the midwall septal image into an analytical fitting routine. The method is depicted in Figure 1. The sign of the curvature depended on the convexity of the septum. A rightward (physiologic) curvature was denoted as a positive value and a leftward curvature as a negative value.

Figure Jump LinkFigure 1. The method of calculating interventricular septal curvature. A, Short-axis cine images of the heart were acquired using double-oblique multiplanar reformation. The interventricular septal curvature was measured in the short-axis image plane at the midventricular level (at least one papillary muscle visible). At this level, the cine image with the most deformation of the septum (at 35% of the R-R interval in this case) was used for quantification. B, Three points at the anterior, middle, and posterior positions on the interventricular septum were marked, and the X and Y coordinates were read. C, A circle that passed through the three points on the septum was used to calculate the radius of curvature of the septum. A rightward (physiologic) curvature was denoted as a positive value and a leftward curvature as a negative value. Window/center settings were 600/150 Hounsfield units.Grahic Jump Location

All IVS curvature measurements were performed by a reader blinded to the subject’s identity. To assess the interobserver reproducibility of the IVS curvature measurements, two independent observers measured the IVS curvature. The correlation of IVS curvature measured by 320-slice CT scan with systolic PAP (sPAP) and mean PAP (mPAP) obtained by RHC was evaluated.

Right-Sided Heart Catheterization

A 7.5F Swan-Ganz thermodilution catheter (Edwards Lifesciences LLC) was used, and a jugular approach was preferred. Pressure measurements were taken from the right atrium, RV, and main pulmonary artery at end expiration. Cardiac output was determined using the thermodilution method by averaging a minimum of three measurements. Left-to-right shunting was ruled out by oximetry.

Pulmonary Digital Subtraction Angiography

For PDSA (Infinix; Toshiba Medical Systems Engineering Co, Ltd), the right- and left-side pulmonary arteries were selectively catheterized using a 7F Berman angiographic balloon catheter (Arrow International, Inc). Arteriograms were acquired at 3 frames/s. Posteroanterior projections of each lung, a right lateral projection of the right side of the lung, and a left anterior oblique or lateral projection of the left side of the lung were obtained. The contrast bolus consisted of 18 mL of iomeprol for each of the four series. The flow rate was 9 mL/s.

PDSA images were digitally stored and analyzed at a picture archiving and communication system workstation (DrABLE-EX; Fujitsu). All arteries were interactively analyzed by two independent observers using two split screens to show the right- and left-sided projections. The two observers were blinded to the subject’s baseline characteristics and CT scan results. Final evaluations were achieved by consensus.

Assessment of Chronic Embolic Findings by CT Scan and PDSA

The observers reviewed the main pulmonary arteries and the right- and left-side lobar and segmental arteries. This resulted in 14 vessel segments on each side (the lingula artery was considered a lobar artery, and the intermediate artery was considered part of the right-side main artery) on both 320-slice CT scan and PDSA. Each vessel segment was judged as positive or negative for the presence of chronic thromboembolic findings.

Statistical Analysis

Sensitivity, specificity, and positive and negative predictive values for the diagnosis of chronic embolic findings on 320-slice CT scan were calculated using PDSA as the gold standard. All images were evaluated in random order, and CT pulmonary angiography (CTPA) and PDSA images were not analyzed in pairs. For comparing CTPA and PDSA, the level of agreement was determined using Cohen κ and its 95% CI. A κ value > 0.81 was interpreted as excellent agreement, and values of 0.61 to 0.80 were interpreted as good agreement, 0.41 to 0.60 as moderate agreement, 0.21 to 0.40 as fair agreement, and < 0.20 as poor agreement. The level of interobserver agreement of CTPA and PDSA was also determined using Cohen κ and its 95% CI.

To determine the interobserver variation of the measurement of IVS curvature, Pearson correlation and Bland-Altman plot analyses were used. The correlation of IVS curvature measured by 320-slice CT scan with hemodynamic data was performed by Pearson correlation analysis.

All results are expressed as the mean ± SD, unless otherwise indicated. For all statistical analyses, P < .05 was considered significant. All analyses were performed using SAS, version 8.0 (SAS Institute Inc) statistical software.

Forty-four consecutive patients (mean age, 59.2 ± 11.3 years; women, 64%) with CTEPH based on RHC and PDSA findings were included in this study (Table 1). One patient did not undergo PDSA because of an allergic reaction to the contrast media. Thus, there were 86 main arteries, 258 lobar arteries, and 860 segmental arteries included in the statistical analysis. CTPA showed chronic thromboembolic findings in 73 of 344 arteries at the main/lobar level and 199 of 860 arteries at the segmental level. The sensitivity and specificity of CTPA to detect chronic thromboembolic findings were 97.0% and 97.1% at the main/lobar level and 85.8% and 94.6% at the segmental level, respectively. CTPA showed excellent agreement compared with PDSA at the main/lobar level (κ = 0.91) and good agreement at the segmental level (κ = 0.79) (Table 2).

Table Graphic Jump Location
Table 1 —Clinical and Hemodynamics Characteristics of the Study Population

Data are presented as mean ± SD or No. (%). mPAP = mean pulmonary artery pressure; PVR = pulmonary vascular resistance; sPAP = systolic pulmonary artery pressure; WHO = World Health Organization.

Table Graphic Jump Location
Table 2 —Summary of Pathologic Vascular Findings as Delineated by CTPA and PDSA and Statistical Analysis of CTPA Findings Compared With PDSA Findings

CTPA = CT pulmonary angiography; NPV = negative predictive value; PDSA = pulmonary digital subtraction angiography; PPV = positive predictive value.

The interobserver agreement between the two observers for PDSA were κ = 0.938 (95% CI, 0.892-0.983) at the main/lobar level and κ = 0.821 (95% CI, 0.776-0.867) at the segmental level. The interobserver agreement for CTPA was similar at the main/lobar (κ = 0.947; 95% CI, 0.906-0.989) and segmental (κ = 0.809; 95% CI, 0.763-0.855) levels.

Evaluation of IVS curvature was feasible in all patients. The maximum septum displacement ranged from a curvature of +0.394 cm to severe leftward IVS bowing with a curvature of −0.339 cm. There was a close correlation between the separate measurements of IVS curvature by two independent observers (r = 0.93, P < .001). Bland-Altman plots showed that the mean interobserver difference in IVS curvature was –0.01 (95% CI, −0.03 to 0.02) (Fig 2).

Figure Jump LinkFigure 2. Bland-Altman plot showing interobserver variability for measurements of interventricular septal curvature. The solid line represents the mean value of the differences in measurements between the two observers (−0.01 cm; 95% CI, −0.03 to 0.02 cm). The dashed lines represent the limits of agreement.Grahic Jump Location

As shown in Figure 3, there was a strong correlation between IVS curvature and sPAP measured by RHC (r = −0.79, P < .001, n = 44). The sPAP showed a linear variation with IVS curvature, with a slope of −74.368 (95% CI, −92.172 to −56.564) and a y-intercept of 74.517 (95% CI, 70.899-78.136). As shown in Figure 4, there was also a strong correlation between IVS curvature and mPAP obtained by RHC (r = −0.86, P < .001, n = 44). The mPAP showed a linear variation with IVS curvature, with a slope of −41.519 (95% CI, −49.190 to −33.847) and a y-intercept of 41.961 (95% CI, 40.401-43.520).

Figure Jump LinkFigure 3. Correlation between interventricular septal curvature obtained by 320-slice CT scan and sPAP based on right-sided heart catheterization. The scatterplot shows the strong relation between interventricular septal curvature and sPAP. The solid line represents the regression line, and the dashed lines represent the 95% CI for the limits of regression. sPAP = systolic pulmonary artery pressure.Grahic Jump Location
Figure Jump LinkFigure 4. Correlation between interventricular septal curvature obtained by 320-slice CT scan and mPAP by right-sided heart catheterization. The scatterplot shows the strong relation between interventricular septal curvature and mPAP. The solid line represents the regression line, and the dotted lines represent the 95% CI for the limits of regression. mPAP = mean pulmonary artery pressure.Grahic Jump Location

To our knowledge, this study is the first to assess the utility of 320-slice CT scan in the diagnosis of CTEPH. There are three main findings. First, 320-slice double-volume CTPA, as well as PDSA, can yield images that allow for the diagnosis of thromboembolic changes in the main/lobar and segmental pulmonary arteries in patients with CTEPH. Second, IVS curvature based on retrospective ECG-gated 320-slice CT scan can estimate PAP in patients with CTEPH. Third, this modality allows for simultaneous and less invasive detection of thrombi and for evaluation of pulmonary hemodynamics for the diagnostic workup of CTEPH.

Despite the fact that CTPA has been a commonly used method in the diagnosis of acute pulmonary embolism, the sensitivity of CTPA to detect CTEPH has been considered to be lower thanV. /Q. lung scintigraphy and single-photon emission CT scanning.5,6,17 Moreover, CTPA can lead to a false-positive diagnosis of CTEPH when there is in situ pulmonary arterial thrombi.18 Nevertheless, previous studies demonstrated the diagnostic accuracy of multislice helical CTPA at the main/lobar and segmental levels in patients with CTEPH.911 The present study also demonstrated that 320-slice CTPA is a less invasive alternative to conventional PDSA for the diagnosis of CTEPH.

In the present study, subsegmental arteries were not included in the analysis because the aim of preoperative imaging was mainly to demonstrate chronic thromboembolic changes in the segmental or more-proximal pulmonary arteries for assessing operability,11,19 although we recently reported subpleural capillary perfusion by PDSA.20 Animal experiments with artificial emboli showed that CTPA as well as PDSA could detect subsegmental pulmonary emboli21,22; however, there is no reference standard for the assessment of subsegmental alterations in humans.23 In addition, previous studies reported that the interobserver agreement at the level of the subsegmental arteries using PDSA was limited.24,25

During the cardiac cycle, the position of the IVS is primarily determined by the difference in pressure between the left ventricle and RV (the transseptal pressure gradient). In patients with PH, right ventricular pressure overload causes a decrease in the transseptal pressure gradient, which is associated with IVS flattening or bowing. In previous studies using echocardiography or cardiac MRI, the distortion of the IVS observed in patients with PH was quantified by measuring the IVS curvature.14,26 Roeleveld et al14 demonstrated a significant correlation between maximal IVS curvature based on cardiac MRI and sPAP measured by RHC in patients with PH (r = 0.77, P < .001). The present study extends their findings and validates the method of deriving mPAP and sPAP from IVS curvature using ECG-gated 320-slice CT imaging.

In previous studies, elevation of mPAP was a strong predictor of mortality in patients with CTEPH who did not undergo an operation.27,28 Saouti et al29 demonstrated that mPAP and pulmonary vascular resistance (PVR) at baseline were strongly related to long-term survival in inoperable patients with CTEPH after initiation of modern vasoactive treatment. Moreover, some studies reported that high PVR was a significant risk factor for the clinical outcome of PEA.30,31 Because of a significant correlation between IVS curvature and PVR determined by RHC in the present study (r = −0.73, P < .001), IVS curvature may predict mortality and clinical outcome in patients with CTEPH.

Although several studies have evaluated image quality of 320-slice CT scans for the heart16,32,33 and brain,34 reports on 320-slice CT images for the lung are limited.3537 Because this imaging modality affords 16-cm craniocaudal coverage, it is possible to image the entire heart (or brain) in a single gantry rotation, but it is technically very difficult to image the whole lung. Therefore, the need for two gantry rotations (double-volume scan) may have limited the use of this modality for lung imaging. Kroft et al36 reported that for small children, the acquisition time with 320-slice CT thoracic imaging was five times faster than that with 64-slice helical CT imaging, and a statistically significant reduction in radiation dose was achieved with 320-slice CT imaging.

Although retrospective ECG-gated cardiac CT scanning can more clearly demonstrate dynamic ventricular morphology than prospective ECG-gated or non-ECG-gated CT scanning, there is a higher radiation dose with retrospective ECG-gated CT scanning than used with other methods.15 The radiation burden with 320-slice volume CT scanning is lower than that with helical CT scanning because it avoids overlapping rotations that are used with helical CT scanning (overscanning). Bischoff et al32 reported that the exposure dose with 320-slice volume CT scan for coronary angiography was only one-fourth of that with 64-slice helical CT scan. In the present study, the total radiation dose was approximately 10-20 mSv, but we also evaluated coronary artery disease on CT scan for assessing the necessity of simultaneous coronary artery bypass graft surgery during PEA as a substitute for conventional invasive coronary angiography.16,19 Therefore, enhanced retrospective ECG-gated double-volume 320-slice CT imaging is appropriate for a routine CTPA protocol in CTEPH. In addition, more recent technical developments (eg, prospective scan triggering during the systolic phase) could reduce the exposure dose in the future.

Sometimes, motion artifacts or differences of density occurred at the junction point of the two gantry rotations. However, this did not affect the assessment of the morphology of the pulmonary arteries and heart. Furthermore, the breath-hold time was no more than 10 s with this modality, which would be beneficial in patients with CTEPH who may be unable to perform the extended breath hold required for MRI.

Technically, 64- or 16-slice helical, as well as 320-slice volume, ECG-gated enhanced CT imaging can assess the morphology of the pulmonary arteries and RV simultaneously. However, they need several times more radiation exposure than 320-slice CT imaging,32 and they need at least 30 s of breath-hold time, which is difficult for patients with CTEPH. Thus, it is difficult to use 64- or 16-slice CT imaging for simultaneous clinical assessment of the pulmonary arteries and RV.

The present study had several limitations. First, this was a single-center retrospective study that included a small number of subjects. Therefore, further multicenter studies are needed in a larger, unselected cohort of patients with suspected PH to evaluate whether 320-slice CTPA is as sensitive asV. /Q. lung scintigraphy to detect CTEPH. Second, not all subjects had different imaging modalities performed on the same day, so changes in hemodynamic conditions during the interval cannot be excluded. Third, the cine image with the most deformation of the septum was used to quantify IVS curvature, but this image may not correspond to the actual end of systole in all patients. This might contribute to some of the discordance observed between the 320-slice CT scan- and RHC-derived sPAP and PVR measurements. The discordance could not be neglected for evaluation of operative risk for CTEPH with high PVR, and RHC should remain mandatory until further improvement in the correlation is achieved. Fourth, only 18 of 44 patients underwent PEA, and pathologic confirmation of the remaining patients’ conditions was not obtained; however, similar results were observed in only surgically treated patients (IVS curvature correlation with sPAP and mPAP, r = −0.81 and −0.83, respectively; P < .001). Finally, although worsening right ventricular failure did not develop in any patients, 100 mL of contrast media and 50 mL of saline were injected for CT scanning, which may have increased RV volume.

The current study demonstrated that double-volume retrospective ECG-gated 320-slice CT imaging angiography allowed for less invasive and simultaneous assessment of the morphology of the pulmonary arteries and pulmonary hemodynamics by the curvature of the IVS in CTEPH. Further investigation is necessary to ascertain whether this modality can replace PDSA for the diagnosis of CTEPH and to determine whether IVS curvature can predict mortality in patients with CTEPH.

Author contributions: Dr Sugiura had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Dr Sugiura: contributed to the study design, data analysis and interpretation, and writing and review of the manuscript.

Dr Tanabe: contributed to the image analysis, data interpretation, and critical review of the manuscript.

Dr Matsuura: contributed to the image analysis and data analysis and interpretation and critical review of the manuscript.

Dr Shigeta: contributed to the image analysis and data analysis and interpretation and critical review of the manuscript.

Dr Kawata: contributed to the data interpretation and critical review of the manuscript.

Dr Jujo: contributed to the RHC and invasive PDSA study and revision of the manuscript.

Mr Yanagawa: contributed to the data interpretation and critical review of the manuscript.

Dr Sakao: contributed to the RHC and invasive PDSA study and critical review of the manuscript.

Dr Kasahara: contributed to the RHC and invasive PDSA study and critical review of the manuscript.

Dr Tatsumi: contributed to the data interpretation and critical review of the manuscript.

Financial/nonfinancial disclosures: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Role of sponsors: The sponsor had no role in the design of the study, the collection and analysis of the data, or in the preparation of the manuscript.

CTEPH

chronic thromboembolic pulmonary hypertension

CTPA

CT pulmonary angiography

IVS

interventricular septum

mPAP

mean pulmonary artery pressure

PAP

pulmonary artery pressure

PDSA

pulmonary digital subtraction angiography

PEA

pulmonary endarterectomy

PH

pulmonary hypertension

PVR

pulmonary vascular resistance

RHC

right-sided heart catheterization

RV

right ventricle

sPAP

systolic pulmonary artery pressure

V. /Q. 

ventilation/perfusion

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Tanabe N, Sugiura T, Jujo T, et al. Subpleural perfusion as a predictor for a poor surgical outcome in chronic thromboembolic pulmonary hypertension. Chest. 2012;141(4):929-934. [CrossRef] [PubMed]
 
Coxson HO, Baile EM, King GG, Mayo JR. Diagnosis of subsegmental pulmonary emboli: a multi-center study using a porcine model. J Thorac Imaging. 2005;20(1):24-31. [CrossRef] [PubMed]
 
Baile EM, King GG, Müller NL, et al. Spiral computed tomography is comparable to angiography for the diagnosis of pulmonary embolism. Am J Respir Crit Care Med. 2000;161(3 pt 1):1010-1015. [PubMed]
 
Schoepf UJ, Costello P. CT angiography for diagnosis of pulmonary embolism: state of the art. Radiology. 2004;230(2):329-337. [CrossRef] [PubMed]
 
Diffin DC, Leyendecker JR, Johnson SP, Zucker RJ, Grebe PJ. Effect of anatomic distribution of pulmonary emboli on interobserver agreement in the interpretation of pulmonary angiography. AJR Am J Roentgenol. 1998;171(4):1085-1089. [CrossRef] [PubMed]
 
Stein PD, Henry JW, Gottschalk A. Reassessment of pulmonary angiography for the diagnosis of pulmonary embolism: relation of interpreter agreement to the order of the involved pulmonary arterial branch. Radiology. 1999;210(3):689-691. [PubMed]
 
King ME, Braun H, Goldblatt A, Liberthson R, Weyman AE. Interventricular septal configuration as a predictor of right ventricular systolic hypertension in children: a cross-sectional echocardiographic study. Circulation. 1983;68(1):68-75. [CrossRef] [PubMed]
 
Riedel M, Stanek V, Widimsky J, Prerovsky I. Longterm follow-up of patients with pulmonary thromboembolism. Late prognosis and evolution of hemodynamic and respiratory data. Chest. 1982;81(2):151-158. [CrossRef] [PubMed]
 
Lewczuk J, Piszko P, Jagas J, et al. Prognostic factors in medically treated patients with chronic pulmonary embolism. Chest. 2001;119(3):818-823. [CrossRef] [PubMed]
 
Saouti N, de Man F, Westerhof N, et al. Predictors of mortality in inoperable chronic thromboembolic pulmonary hypertension. Respir Med. 2009;103(7):1013-1019. [CrossRef] [PubMed]
 
Ishida K, Masuda M, Tanabe N.Matsumiya G, Tatsumi K, Nakajima N. Long-term outcome after pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension. J Thorac Cardiovasc Surg. 2012;144(2):321-326. [CrossRef] [PubMed]
 
Corsico AG, D’Armini AM, Cerveri I, et al. Long-term outcome after pulmonary endarterectomy. Am J Respir Crit Care Med. 2008;178(4):419-424. [CrossRef] [PubMed]
 
Bischoff B, Hein F, Meyer T, et al. Comparison of sequential and helical scanning for radiation dose and image quality: results of the Prospective Multicenter Study on Radiation Dose Estimates of Cardiac CT Angiography (PROTECTION) I Study. AJR Am J Roentgenol. 2010;194(6):1495-1499. [CrossRef] [PubMed]
 
Rybicki FJ, Otero HJ, Steigner ML, et al. Initial evaluation of coronary images from 320-detector row computed tomography. Int J Cardiovasc Imaging. 2008;24(5):535-546. [CrossRef] [PubMed]
 
Diekmann S, Siebert E, Juran R, et al. Dose exposure of patients undergoing comprehensive stroke imaging by multidetector-row CT: comparison of 320-detector row and 64-detector row CT scanners. AJNR Am J Neuroradiol. 2010;31(6):1003-1009. [CrossRef] [PubMed]
 
Silverman JD, Paul NS, Siewerdsen JH. Investigation of lung nodule detectability in low-dose 320-slice computed tomography. Med Phys. 2009;36(5):1700-1710. [CrossRef] [PubMed]
 
Kroft LJ, Roelofs JJ, Geleijns J. Scan time and patient dose for thoracic imaging in neonates and small children using axial volumetric 320-detector row CT compared to helical 64-, 32-, and 16-detector row CT acquisitions. Pediatr Radiol. 2010;40(3):294-300. [CrossRef] [PubMed]
 
Yamashiro T, Miyara T, Takahashi M, et al;; ACTIve Study Group ACTIve Study Group. Lung image quality with 320-row wide-volume CT scans: the effect of prospective ECG-gating and comparisons with 64-row helical CT scans. Acad Radiol. 2012;19(4):380-388. [CrossRef] [PubMed]
 

Figures

Figure Jump LinkFigure 1. The method of calculating interventricular septal curvature. A, Short-axis cine images of the heart were acquired using double-oblique multiplanar reformation. The interventricular septal curvature was measured in the short-axis image plane at the midventricular level (at least one papillary muscle visible). At this level, the cine image with the most deformation of the septum (at 35% of the R-R interval in this case) was used for quantification. B, Three points at the anterior, middle, and posterior positions on the interventricular septum were marked, and the X and Y coordinates were read. C, A circle that passed through the three points on the septum was used to calculate the radius of curvature of the septum. A rightward (physiologic) curvature was denoted as a positive value and a leftward curvature as a negative value. Window/center settings were 600/150 Hounsfield units.Grahic Jump Location
Figure Jump LinkFigure 2. Bland-Altman plot showing interobserver variability for measurements of interventricular septal curvature. The solid line represents the mean value of the differences in measurements between the two observers (−0.01 cm; 95% CI, −0.03 to 0.02 cm). The dashed lines represent the limits of agreement.Grahic Jump Location
Figure Jump LinkFigure 3. Correlation between interventricular septal curvature obtained by 320-slice CT scan and sPAP based on right-sided heart catheterization. The scatterplot shows the strong relation between interventricular septal curvature and sPAP. The solid line represents the regression line, and the dashed lines represent the 95% CI for the limits of regression. sPAP = systolic pulmonary artery pressure.Grahic Jump Location
Figure Jump LinkFigure 4. Correlation between interventricular septal curvature obtained by 320-slice CT scan and mPAP by right-sided heart catheterization. The scatterplot shows the strong relation between interventricular septal curvature and mPAP. The solid line represents the regression line, and the dotted lines represent the 95% CI for the limits of regression. mPAP = mean pulmonary artery pressure.Grahic Jump Location

Tables

Table Graphic Jump Location
Table 1 —Clinical and Hemodynamics Characteristics of the Study Population

Data are presented as mean ± SD or No. (%). mPAP = mean pulmonary artery pressure; PVR = pulmonary vascular resistance; sPAP = systolic pulmonary artery pressure; WHO = World Health Organization.

Table Graphic Jump Location
Table 2 —Summary of Pathologic Vascular Findings as Delineated by CTPA and PDSA and Statistical Analysis of CTPA Findings Compared With PDSA Findings

CTPA = CT pulmonary angiography; NPV = negative predictive value; PDSA = pulmonary digital subtraction angiography; PPV = positive predictive value.

References

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Dewey M, Zimmermann E, Deissenrieder F, et al. Noninvasive coronary angiography by 320-row computed tomography with lower radiation exposure and maintained diagnostic accuracy: comparison of results with cardiac catheterization in a head-to-head pilot investigation. Circulation. 2009;120(10):867-875. [CrossRef] [PubMed]
 
Bajc M, Jonson B. Ventilation/perfusion SPECT for diagnosis of pulmonary embolism and other diseases. Int J Mol Imaging. 2011;2011:682949. [PubMed]
 
Moser KM, Fedullo PF, Finkbeiner WE, Golden J. Do patients with primary pulmonary hypertension develop extensive central thrombi?. Circulation. 1995;91(3):741-745. [CrossRef] [PubMed]
 
Kim NH. Assessment of operability in chronic thromboembolic pulmonary hypertension. Proc Am Thorac Soc. 2006;3(7):584-588. [CrossRef] [PubMed]
 
Tanabe N, Sugiura T, Jujo T, et al. Subpleural perfusion as a predictor for a poor surgical outcome in chronic thromboembolic pulmonary hypertension. Chest. 2012;141(4):929-934. [CrossRef] [PubMed]
 
Coxson HO, Baile EM, King GG, Mayo JR. Diagnosis of subsegmental pulmonary emboli: a multi-center study using a porcine model. J Thorac Imaging. 2005;20(1):24-31. [CrossRef] [PubMed]
 
Baile EM, King GG, Müller NL, et al. Spiral computed tomography is comparable to angiography for the diagnosis of pulmonary embolism. Am J Respir Crit Care Med. 2000;161(3 pt 1):1010-1015. [PubMed]
 
Schoepf UJ, Costello P. CT angiography for diagnosis of pulmonary embolism: state of the art. Radiology. 2004;230(2):329-337. [CrossRef] [PubMed]
 
Diffin DC, Leyendecker JR, Johnson SP, Zucker RJ, Grebe PJ. Effect of anatomic distribution of pulmonary emboli on interobserver agreement in the interpretation of pulmonary angiography. AJR Am J Roentgenol. 1998;171(4):1085-1089. [CrossRef] [PubMed]
 
Stein PD, Henry JW, Gottschalk A. Reassessment of pulmonary angiography for the diagnosis of pulmonary embolism: relation of interpreter agreement to the order of the involved pulmonary arterial branch. Radiology. 1999;210(3):689-691. [PubMed]
 
King ME, Braun H, Goldblatt A, Liberthson R, Weyman AE. Interventricular septal configuration as a predictor of right ventricular systolic hypertension in children: a cross-sectional echocardiographic study. Circulation. 1983;68(1):68-75. [CrossRef] [PubMed]
 
Riedel M, Stanek V, Widimsky J, Prerovsky I. Longterm follow-up of patients with pulmonary thromboembolism. Late prognosis and evolution of hemodynamic and respiratory data. Chest. 1982;81(2):151-158. [CrossRef] [PubMed]
 
Lewczuk J, Piszko P, Jagas J, et al. Prognostic factors in medically treated patients with chronic pulmonary embolism. Chest. 2001;119(3):818-823. [CrossRef] [PubMed]
 
Saouti N, de Man F, Westerhof N, et al. Predictors of mortality in inoperable chronic thromboembolic pulmonary hypertension. Respir Med. 2009;103(7):1013-1019. [CrossRef] [PubMed]
 
Ishida K, Masuda M, Tanabe N.Matsumiya G, Tatsumi K, Nakajima N. Long-term outcome after pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension. J Thorac Cardiovasc Surg. 2012;144(2):321-326. [CrossRef] [PubMed]
 
Corsico AG, D’Armini AM, Cerveri I, et al. Long-term outcome after pulmonary endarterectomy. Am J Respir Crit Care Med. 2008;178(4):419-424. [CrossRef] [PubMed]
 
Bischoff B, Hein F, Meyer T, et al. Comparison of sequential and helical scanning for radiation dose and image quality: results of the Prospective Multicenter Study on Radiation Dose Estimates of Cardiac CT Angiography (PROTECTION) I Study. AJR Am J Roentgenol. 2010;194(6):1495-1499. [CrossRef] [PubMed]
 
Rybicki FJ, Otero HJ, Steigner ML, et al. Initial evaluation of coronary images from 320-detector row computed tomography. Int J Cardiovasc Imaging. 2008;24(5):535-546. [CrossRef] [PubMed]
 
Diekmann S, Siebert E, Juran R, et al. Dose exposure of patients undergoing comprehensive stroke imaging by multidetector-row CT: comparison of 320-detector row and 64-detector row CT scanners. AJNR Am J Neuroradiol. 2010;31(6):1003-1009. [CrossRef] [PubMed]
 
Silverman JD, Paul NS, Siewerdsen JH. Investigation of lung nodule detectability in low-dose 320-slice computed tomography. Med Phys. 2009;36(5):1700-1710. [CrossRef] [PubMed]
 
Kroft LJ, Roelofs JJ, Geleijns J. Scan time and patient dose for thoracic imaging in neonates and small children using axial volumetric 320-detector row CT compared to helical 64-, 32-, and 16-detector row CT acquisitions. Pediatr Radiol. 2010;40(3):294-300. [CrossRef] [PubMed]
 
Yamashiro T, Miyara T, Takahashi M, et al;; ACTIve Study Group ACTIve Study Group. Lung image quality with 320-row wide-volume CT scans: the effect of prospective ECG-gating and comparisons with 64-row helical CT scans. Acad Radiol. 2012;19(4):380-388. [CrossRef] [PubMed]
 
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