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Correlation of Pulmonary Artery Dimensions Between Endobronchial Ultrasound and CT ScanPulmonary Artery Dimension by Ultrasound FREE TO VIEW

Milind Baldi, MD; Sahajal Dhooria, DM; Ashutosh N. Aggarwal, DM, FCCP; Ritesh Agarwal, DM, FCCP
Author and Funding Information

From the Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER).

CORRESPONDENCE TO: Ritesh Agarwal, DM, FCCP, Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh-160012, India; e-mail: agarwal.ritesh@live.com


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.

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


Chest. 2015;147(3):e113-e114. doi:10.1378/chest.14-2705
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To the Editor:

The dimensions of the pulmonary artery (PA) on CT scan and the ratio of the main PA to ascending aorta (AA) have been shown to correlate with the diagnosis and severity of pulmonary hypertension.1 The mediastinal vessels are easily visualized with convex probe endobronchial ultrasound (EBUS) as the depth of penetration with EBUS is approximately 5 cm; also, the vessels run adjacent to the airway, and there is no interposition of aerated lung between airways and vessels.2 Whether the measurements of PA dimensions performed by EBUS correlate with CT scan measurements of the PA remains unknown.

A prospective observational study was undertaken over a period of 2 months at our center. Written informed consent was obtained from all patients, and the study protocol was approved by the ethics review committee. All patients aged 18 years or older and undergoing EBUS were eligible for inclusion in the study. Patients with visible extrinsic compression of mediastinal vasculature on chest CT scan and those who failed to provide informed consent were excluded. The dimensions of the left PA (LPA) and the AA were documented in all cases. The diameter of the LPA, just distal to bifurcation of the main PA, was measured by contrast-enhanced CT scan with the help of calipers. In the same section, the diameter of the AA was also measured. While performing EBUS (BF-UC 180F with compatible endoscopic ultrasound unit EU-ME1; Olympus Medical Systems), the bronchoscope was turned to the 10 o’clock position facing the main carina with the tip flexed and apposed to the tracheal wall just proximal to the carina. The dimensions of the LPA and the AA were measured at this level, and an average of long-axis and short-axis diameters was used for calculation. Microsoft Excel 2010 was used for the data analysis.

A total of 30 cases (mean age, 49.8 years; 20 men) were included for the final analysis. The clinical indications included sarcoidosis (n = 12), malignancy (n = 8), TB (n = 6), and others (n = 4). The dimensions recorded by both the modalities are shown in Table 1. There was a statistically significant correlation between the values measured on CT scan and EBUS (Table 1). However, the limits of agreement were wide, indicating that the two measurements cannot be used interchangeably (Fig 1).

Table Graphic Jump Location
TABLE 1 ]  Mean Diameter of LPA and AA as Recorded by CT Scan and EBUS

AA = ascending aorta; EBUS = endobronchial ultrasound; LPA = left pulmonary artery.

Figure Jump LinkFigure 1 –  A, B, Bland-Altman plot showing magnitude of difference between measurements of pulmonary artery (A) and aorta (B) performed on CT scan and EBUS expressed in millimeters. Horizontal dashed lines represent the mean bias and its 95% confidence limits. EBUS = endobronchial ultrasound.Grahic Jump Location

The diagnostic spectrum of EBUS has rapidly evolved since its inception in 2001 including its utility in diagnosis of pulmonary thromboembolism and tumor embolism.2,3 A correlation between dimensions of airway, measured on EBUS and CT scan, has been described.4 We found a significant correlation between the parameters measured by CT scan and EBUS. However, the limits of agreement were wide (approximately 30% of the vascular diameters). Hence, measuring the dimensions of great vessels through EBUS is unlikely to contribute significantly in the management of pulmonary hypertension. Importantly, it was difficult to assess the diameter of the main PA as it would not fit into the scanning range of EBUS. Due to the small sample size, larger studies are required to confirm our observations.

References

McCann C, Gopalan D, Sheares K, Screaton N. Imaging in pulmonary hypertension, part 1: clinical perspectives, classification, imaging techniques and imaging algorithm. Postgrad Med J. 2012;88(1039):271-279. [CrossRef] [PubMed]
 
Aumiller J, Herth FJ, Krasnik M, Eberhardt R. Endobronchial ultrasound for detecting central pulmonary emboli: a pilot study. Respiration. 2009;77(3):298-302. [CrossRef] [PubMed]
 
Chamorro N, Blanco I, Sánchez M, Ramírez J, Barberà JA, Agustí C. The expanding horizons of endobronchial ultrasound: diagnosis of a tumor embolism. Chest. 2012;142(5):1334-1336. [CrossRef] [PubMed]
 
Nobuyama S, Kurimoto N, Matsuoka S, et al. Airway measurements in tracheobronchial stenosis using endobronchial ultrasonography during stenting. J Bronchology Interv Pulmonol. 2011;18(2):128-132. [CrossRef] [PubMed]
 

Figures

Figure Jump LinkFigure 1 –  A, B, Bland-Altman plot showing magnitude of difference between measurements of pulmonary artery (A) and aorta (B) performed on CT scan and EBUS expressed in millimeters. Horizontal dashed lines represent the mean bias and its 95% confidence limits. EBUS = endobronchial ultrasound.Grahic Jump Location

Tables

Table Graphic Jump Location
TABLE 1 ]  Mean Diameter of LPA and AA as Recorded by CT Scan and EBUS

AA = ascending aorta; EBUS = endobronchial ultrasound; LPA = left pulmonary artery.

References

McCann C, Gopalan D, Sheares K, Screaton N. Imaging in pulmonary hypertension, part 1: clinical perspectives, classification, imaging techniques and imaging algorithm. Postgrad Med J. 2012;88(1039):271-279. [CrossRef] [PubMed]
 
Aumiller J, Herth FJ, Krasnik M, Eberhardt R. Endobronchial ultrasound for detecting central pulmonary emboli: a pilot study. Respiration. 2009;77(3):298-302. [CrossRef] [PubMed]
 
Chamorro N, Blanco I, Sánchez M, Ramírez J, Barberà JA, Agustí C. The expanding horizons of endobronchial ultrasound: diagnosis of a tumor embolism. Chest. 2012;142(5):1334-1336. [CrossRef] [PubMed]
 
Nobuyama S, Kurimoto N, Matsuoka S, et al. Airway measurements in tracheobronchial stenosis using endobronchial ultrasonography during stenting. J Bronchology Interv Pulmonol. 2011;18(2):128-132. [CrossRef] [PubMed]
 
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