HOME SUBSCRIPTIONS CURRENT ISSUE PAST ISSUES CARDIOSOURCE SEARCH HELP FEEDBACK		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) All Versions of this Article: j.jacc.2007.01.077v1 49/18/1880    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Wu, M.-T. Articles by Yang, T.-L. Search for Related Content PubMed Articles by Wu, M.-T. Articles by Yang, T.-L.

CLINICAL RESEARCH: CONGENITAL HEART DISEASE

Influence of Pulmonary Regurgitation Inequality on Differential Perfusion of the Lungs in Tetralogy of Fallot After Repair

A Phase-Contrast Magnetic Resonance Imaging and Perfusion Scintigraphy Study

Ming-Ting Wu, MD^_*,,_*, Yi-Luan Huang, MD^_*,, Kai-Sheng Hsieh, MD, Ju-Tung Huang, MD^_*,, Nan-Jing Peng, MD^_*,, Jun-Yen Pan, MD^_*,||, Jer-Shyung Huang^_*,,¶ and Tsung-Lung Yang^_*,,¶

^_* Faculty of Medicine, School of Medicine, National Yang Ming University, Taipei, Taiwan
Department of Radiology
Department of Pediatrics
Department of Nuclear Medicine
^|| Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
^¶ Shu Zen College of Medicine and Management, Kaohsiung, Taiwan

Manuscript received October 2, 2006; revised manuscript received January 23, 2007, accepted January 27, 2007.

^_* Reprint requests and correspondence: Dr. Ming-Ting Wu, Section of Thoracic and Circulation Imaging, Department of Radiology; Kaohsiung Veterans General Hospital, No. 386, Ta-Chung 1st Road, Kaohsiung, Taiwan 813, R.O.C. (Email: wu.mingting{at}gmail.com).

Objectives: The purpose of this study was to evaluate the influence of pulmonary regurgitation inequality on differential perfusion of the lungs in tetralogy of Fallot (TOF) after repair.

Background: Asymmetry of lung perfusion is one of the best predictors of outcome in TOF after repair. A recent phase-contrast magnetic resonance imaging (PC-MRI) study found prominent regurgitation inequality between the bilateral pulmonary arteries in TOF after repair.

Methods: Forty-three TOF post-repair patients (median age = 51 months, 31 men) received PC-MRI and ^99mTc-labeled macroaggregates of albumin perfusion scintigraphy (PS) in the same day. We took PC-MRI measurements of forward flow volume (FFV), backward flow volume (BFV), and net flow volume (NFV) (NFV = FFV – BFV) and regurgitation fraction (RF) (RF = BFV/FFV) at the left and right pulmonary arteries (LPA and RPA). The differential perfusion of the left lung (L%) (L% = left lung/left + right lung) as calculated by NFV ratio, by FFV ratio of PC-MRI, and by PS were compared.

Results: The discrepancy between L% by NFV versus L% by PS was affected by the severity of RF of LPA (r = –0.51, p = 0.001); agreement between L% by NFV versus L% by PS was good (intraclass correlation coefficient [Ri] = 0.87) if RF of LPA <0.4 (n = 23) but downgraded (Ri = 0.51) and underestimated the L% (median of error = –14%, range = –25.3% to 5.5%) if RF of LPA 0.4 (n = 20). In contrast, agreement between L% by FFV versus L% by PS was high and unaffected by RF of LPA (Ri = 0.94, 0.92, respectively).

Conclusions: While integrating PC-MRI of pulmonary artery as a comprehensive MRI evaluation of TOF after repair, conventional NFV ratio method tended to underestimate the left lung perfusion and may lead to unnecessary intervention. The FFV ratio method should be used for precise assessment of differential lung perfusion.

Abbreviations and Acronyms   BFV = backward flow volume   FFV = forward flow volume   LPA = left pulmonary artery   L% = differential perfusion of the left lung   NFV = net flow volume   PC-MRI = phase-contrast magnetic resonance imaging   PS = 99mTc-labeled macroaggregates of albumin perfusion scintigraphy   RF = regurgitation fraction   RPA = right pulmonary artery   TOF = tetralogy of Fallot