Pooler BD, et al. Radiology. 2018;doi:10.1148/radiol.2018181134.

December 18, 2018
2 min read

Bariatric surgery for obesity improves hepatic steatosis


Pooler BD, et al. Radiology. 2018;doi:10.1148/radiol.2018181134.

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Bariatric surgery with preoperative very low-calorie diet significantly improved hepatic steatosis in patients with obesity regardless of starting weight or overall weight loss, according to magnetic resonance imaging-estimated proton density fat fraction data from a recently published study.

“The results showed a rapid early phase of improvements in liver fat, followed by a phase of continued improvements at a slower pace,” study coauthor B. Dustin Pooler, MD, from the University of Wisconsin School of Medicine, said in a press release. “The changes began with the initiation of the low-calorie diet and occurred in advance of the overall improvements in BMI among the patients.”

Fifty patients with obesity completed MRI examinations at baseline, near the conclusion of the low-calorie diet before surgery, 1 month after surgery and 3 months after surgery, with 40 patients completing the final MRI follow-up between 6 months and 10 months after surgery.

At baseline, mean liver PDFF was 18.1%, mean BMI was 44.9 kg/m2, mean weight was 121.5 kg, and mean waist circumference was 132.2 cm.

At study end, all measurements decreased significantly (P < .0001); mean liver PDFF decreased to 4.9%, final mean BMI was 34.5 kg/m2, mean weight was 91.6 kg, and mean waist circumference was 110.9 cm.

“Our observations suggest that reductions in liver fat relative to anthropometrics occur most rapidly, but more variably, during the first 6 weeks of the treatment course,” Pooler and colleagues wrote, referring to the low-calorie diet and early postsurgery periods. “Following this short-term period of rapid loss, the decline slowed but persisted at a relatively steady rate through the final 6-month postsurgery mark.”

Each measure decreased significantly during both the 6-week period and the 6-month conclusion (P < .001). Decreased measurements were significantly higher during the 6-week period compared with the 6-month period for PDFF, BMI and weight (P < .001) and for waist circumference (P = .01).

Thirty-two of 50 patients achieved normalized PDFF less than 5%. The mean time to PDFF normalization was approximately 22.5 weeks. The researchers estimated that 90% of study participants would achieve normalized PDFF by 42 weeks.

Multivariate analysis showed that lower baseline PDFF measurements predicted shorter time to normalization (r = 0.72; P < .001).

“We looked at bariatric surgery patients in our study, but there's no reason this clinical tool can't be used to monitor all sorts of weight loss patients,” Pooler said in the press release. “We want patients and physicians to know that this is an option for them. We've done the validation and the next step is to make people more aware of this option.” – by Talitha Bennett

Disclosure: Pooler reports no relevant financial disclosures. Please see the full study for the other authors’ relevant financial disclosures.