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Differential regional lung uptake analysis of the lung scan as an adjunct to interpretation of pulmonary embolism

Ali, Layla; Loutfi, Issa; Hadi, Nadiyah; Burezq, Salwa

Nuclear Medicine Communications: June 2014 - Volume 35 - Issue 6 - p 638–642
doi: 10.1097/MNM.0000000000000098
Original Articles

Objective Differential regional lung uptake (DRLU) analysis of a lung perfusion scan is used to provide information on diversion of the radiotracer from areas supplied by obstructed pulmonary artery branches to areas with patent vessels, which could assist in the diagnosis of pulmonary embolism (PE), especially the intermediate-probability studies.

Methods Lung perfusion scans performed over 3 years (n=121) were analyzed using a computer overlay of six regions of interest per lung on the posterior view. DRLU was defined for neighboring region pairs as the ratio of the difference in the average count rate to the sum of the count rate in the region pair for a total of 18 region pairs per study.

Results Comparison of the DRLU for high-probability studies (n=30) with normal scans (n=40) showed significant deviation in a least three region pairs per study. For low-probability scans (n=30), there was no significant deviation from the normal. For the intermediate category (n=21), a subgroup (n=7) showed significant deviation in at least three region pairs, which also had a positive computed tomography pulmonary angiography for PE, and another subgroup (n=14) had deviation in two or fewer region pairs with a negative computed tomography pulmonary angiography.

Conclusion Using DRLU analysis, intermediate scans for PE could be redefined as low or high probability, on the basis of the number of region pairs showing deviation of DRLU. This could lead to improved diagnostic performance of the study without recourse to additional maneuvers or specialized equipment and would obviate the need for more tests on the patient.

Departments of Radiological Sciences and Nuclear Medicine, Faculties of Allied Health Sciences and Medicine, Kuwait University, Kuwait

Correspondence to Issa Loutfi, MD, MSc, PhD, Department of Nuclear Medicine, Faculty of Medicine, Kuwait University, PO Box 24923, 13110 Safat, Kuwait Tel: +965 2463 6414/965 2531 9592; fax: +965 2533 8936; e-mails: loutfi@hsc.edu.kw, issaloutfi@hotmail.com

Received January 9, 2014

Accepted January 29, 2014

© 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins