T. SUZUKI1, R. B. Luo1, J. C. Hooker2, Y. Covarrubias2, T. Wolfson2, A. Schlein2, S. Liu1, J. B. Schwimmer3, L. M. Funk5, J. A. Greenberg5, G. M. Campos6, B. J. Sandler1, S. Horgan1, S. B. Reeder4, C. B. Sirlin2, G. R. Jacobsen1 1University Of California – San Diego,Division Of Minimally Invasive Surgery, Department Of Surgery,San Diego, CA, USA 2University Of California – San Diego,Liver Imaging Group, Department Of Radiology,San Diego, CA, USA 3University Of California – San Diego,Division Of Gastroenterology, Hepatology, And Nutrition, Department Of Pediatrics,San Diego, CA, USA 4University Of Wisconsin,Departments Of Radiology, Medical Physics, Biomedical Engineering, Medicine And Emergency Medicine,Madison, WI, USA 5University Of Wisconsin,Department Of Surgery,Madison, WI, USA 6Virginia Commonwealth University,Division Of Bariatric And GI Surgery,Richmond, VA, USA
Introduction: Liver volume (LV) and fat content are important considerations during bariatric procedures as increased liver volume not only increases the difficulty of intra-operative visualization but also elevates the risk of bleeding complications. The aim of this study was to evaluate the impact of a preoperative liquid diet (PLD) on LV and magnetic resonance imaging (MRI) estimated proton density fat fraction (PDFF) as a measure of liver fat content, in morbidly obese patients undergoing bariatric surgery (BS).
Methods: This prospective multi-institutional study was approved by an institutional review board (IRB) and was Health Insurance Portability and Accountability Act (HIPAA) compliant. After providing informed consent, patients meeting National Institutes of Health (NIH) criteria for BS underwent MRI at baseline and post PLD. LV and PDFF were estimated from 3D chemical shift encoded MRI (CSE-MRI) anatomical images and PDFF maps, using the OsiriX (Pixmeo SARL, Bernex, Switzerland) imaging software. Primary outcomes were patient weight, body mass index (BMI), LV and PDFF. Secondary outcomes were relationships between the changes in BMI, LV and PDFF. Data were analyzed with paired t-test and Wilcoxon-Mann-Whitney tests. Pearson correlation was used to assess the relationships between measures. Relative reduction rate of BMI was defined as: (baseline BMI – post BMI) / baseline BMI ×100 (%). Relative reduction rate of LV was defined as: (baseline LV – post LV) / baseline LV ×100 (%). The absolute reduction rate of PDFF was defined as: baseline PDFF ?post PDFF (%).
Results:One-hundred-twenty-four patients scheduled for BS were recruited to be part of the study between October 2010 and June 2015. 102 patients (87 females, 85.3%, mean age 48.0 ± 12.8 years) underwent MRI at baseline and post PLD. The mean liquid diet duration was 17.1 ± 8.8 days. Post PLD, mean weight decreased from 119.6 ± 19.1 kg/m2 to 114.8 ± 18.7 kg/m2 (p<0.0001). BMI decreased from 43.6 ± 6.4 kg/m2 to 41.9 ± 6.3 kg/m2 (p<0.0001) with a mean relative reduction of 4.1 ± 2.2 %. LV decreased from 2277.2 ± 578.0 cm3 to 1985.0 ± 510.6 cm3 (p<0.0001) with a mean relative reduction of 12.3 ± 10.1 %. PDFF decreased from 13.6 ± 9.4 % to 10.4 ± 7.8 % (p<0.0001) with a mean absolute reduction of 3.2 ± 4.3 %. Pearson correlations analyses revealed statistically significant relationships between the relative reductions in LV and BMI (r=0.5253, p≤0.0001), between the absolute reduction in PDFF and relative reduction in BMI (r=0.2451, p=0.0140), and between the absolute reduction in PDFF and relative reduction in LV (r=0.3861, p=0.0001).
Conclusion:PLD significantly reduced LV and PDFF. This highlights the importance of PLD in the improvement of LV and PDFF in morbidly obese patients and underscores the reason why PLD is routinely performed at our institutions.