Detection of non-alcoholic steatohepatitis in patients with morbid obesity before bariatric surgery: preliminary evaluation with acoustic radiation force impulse imaging.
OBJECTIVE
To investigate the utility of acoustic radiation force impulse (ARFI) imaging, with the determination of shear wave velocity (SWV), to differentiate non-alcoholic fatty liver disease (NAFLD) from non-alcoholic steatohepatitis (NASH) in patients with morbid obesity before bariatric surgery.


METHODS
Thirty-two patients with morbid obesity were evaluated with ARFI and conventional ultrasound before bariatric surgery. The ARFI and ultrasound results were compared with liver biopsy findings, which is the reference standard. The patients were classed according to their histological findings into three groups: group A, simple steatosis; group B, inflammation; and group C, fibrosis.


RESULTS
The median SWV was 1.57 ± 0.79 m/s. Hepatic alterations were observed in the histopathological findings for all the patients in the study (100 %), with the results of the laboratory tests proving normal. Differences in SWV were also observed between groups A, B and C: 1.34 ± 0.90 m/s, 1.55 ± 0.79 m/s and 1.86 ± 0.75 m/s (P < 0.001), respectively. The Az for differentiating NAFLD from NASH or fibrosis was 0.899 (optimal cut-off value 1.3 m/s; sensitivity 85 %; specificity 83.3 %).


CONCLUSIONS
The ARFI technique is a useful diagnostic tool for differentiating NAFLD from NASH in asymptomatic patients with morbid obesity.


CONCLUSIONS
• Acoustic radiation force impulse imaging provides ultrasonic shear wave velocity measurements.                                  • SWV measurements were higher in patients with inflammation or fibrosis than NAFLD.                 • ARFI differentiates NAFLD from NASH in patients with morbid obesity.                                  • Results suggest that ARFI can detect NASH in asymptomatic morbidly obese patients.
Department of of Radiology, Virgen de la Arrixaca University Hospital, 30120, El Palmar, Murcia, Spain.
F
F
Guzmán-Aroca
M D
MD
Frutos-Bernal
A
A
Bas
J A
JA
Luján-Mompeán
M
M
Reus
Juan de Dios
Jde D
Berná-Serna
P
P
Parrilla
D000162:Acoustics; D000328:Adult; D050110:Bariatric Surgery / Q000379:methods*; D001706:Biopsy; D005234:Fatty Liver / Q000150:complications* / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007249:Inflammation; D008099:Liver / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease; D009767:Obesity, Morbid / Q000150:complications*; D011446:Prospective Studies; D012372:ROC Curve; D012015:Reference Standards; D015203:Reproducibility of Results; D033081:Shear Strength; D013314:Stress, Mechanical; D014463:Ultrasonography / Q000379:methods*