Focal fatty sparing as an indicator of higher-grade fatty liver assessed by attenuation imaging: a prospective clinical study in NAFLD population

Abstract

Background As part of a prospective clinical study, the degree of hepatic fatty degeneration was quantified in a patient population with nonalcoholic fatty liver disease and sonographically diagnosed with hepatic steatosis using attenuation imaging.

Methods A total of 113 patients with hepatic steatosis were examined, of whom 35 showed focal fatty sparing. Patients with the condition after right nephrectomy, other known liver diseases, and relevant alcohol consumption were excluded from the evaluation. B-scan sonography and sonographic quantification of steatosis content using attenuation imaging (Aplio i800 Canon Medical Systems) were performed. Attenuation imaging is a new ultrasound-based measurement technique that allows objective detection and quantification of hepatic steatosis.

Results The prevalence of focal fatty sparing was 31.0% in the patient population examined. Patients with focal fatty sparing showed a statistically significantly higher attenuation coefficient in contrast to patients without focal fatty sparing (0.79 ± 0.10 vs. 0.66 ± 0.09 dB/cm/MHz, p < 0.0001).

Conclusion Detection of focal fatty sparing is associated with an increased attenuation coefficient and is thus an expression of higher-grade hepatic fatty degeneration. Patients with focal fatty sparing are more often male and have a higher BMI and a larger liver than patients with nonalcoholic fatty liver disease without focal fatty sparing.

Zusammenfassung

Hintergrund Im Rahmen einer prospektiven klinischen Studie wurde der Grad der hepatischen Fettdegeneration bei einer Patientenpopulation mit nichtalkoholischer Fettlebererkrankung und sonografisch diagnostizierter Steatosis hepatis mittels Attenuationsbildgebung quantifiziert.

Methoden Insgesamt wurden 113 Patienten mit einer Fettleber untersucht, von denen 35 eine fokale Minderverfettung aufwiesen. Patienten mit Zustand nach rechter Nephrektomie, anderen bekannten Lebererkrankungen und relevantem Alkoholkonsum wurden von der Untersuchung ausgeschlossen. Es wurden eine B-Bild-Sonografie und eine sonografische Quantifizierung des Steatosegehalts mittels Attenuation Imaging (Aplio i800 Canon Medical Systems) durchgeführt. Attenuation Imaging ist eine neue ultraschallbasierte Messtechnik, die eine objektive Erkennung und Quantifizierung der Lebersteatose ermöglicht.

Ergebnisse Die Prävalenz der fokalen Minderverfettung betrug in der untersuchten Patientenpopulation 31,0 %. Patienten mit fokaler Minderverfettung zeigten im Gegensatz zu Patienten ohne fokale Minderverfettung einen statistisch signifikant höheren Attenuation coefficient (0,79 ± 0,10 vs. 0,66 ± 0,09 dB/cm/MHz, p < 0,0001).

Schlussfolgerung Der Nachweis einer fokalen Verfettung geht mit einem erhöhten Attenuation coefficient einher und ist somit Ausdruck einer höhergradigen Leberverfettung. Patienten mit fokaler Minderverfettung sind häufiger männlich, haben einen höheren BMI und eine größere Leber als Patienten mit nichtalkoholischer Fettlebererkrankung ohne fokale Minderverfettung.

Schlüsselwörter

Schallwellenattenuation - Fokale Minderverfettung - Fettlebererkrankung - Leber

Keywords

Attenuation Imaging - Focal fatty sparing - Hepatic steatosis - Liver

Publication History

Received: 10 September 2021

Accepted after revision: 07 November 2021

Article published online:
14 December 2021

• References

• 1 Younossi ZM, Koenig AB, Abdelatif D. et al. Global epidemiology of nonalcoholic fatty liver disease—meta-analytic assessment of prevalence, incidence, and outcomes. Hepatology 2016; 64: 73-84 DOI: 10.1002/hep.28431. (PMID: 26707365)
• 2 European Association for the Study of the Liver, European Association for the Study of Diabetes, European Association for the Study of Obesity. EASL-EASD-EASO Clinical Practice Guidelines for the Management of Nonalcoholic Fatty Liver Disease. J Hepatol 2016; 64: 1388-1402 DOI: 10.1016/j.jhep.2015.11.004.
• 3 Hernaez R, Lazo M, Bonekamp S. et al. Diagnostic accuracy and reliability of ultrasonography for the detection of fatty liver: a meta-analysis. Hepatology 2011; 54: 1082-1090 DOI: 10.1002/hep.24452. (PMID: 21618575)
• 4 Dasarathy S, Dasarathy J, Khiyami A. et al. Validity of real time ultrasound in the diagnosis of hepatic steatosis: a prospective study. J Hepatol 2009; 51: 1061-1067 DOI: 10.1016/j.jhep.2009.09.001. (PMID: 19846234)
• 5 Bae JS, Lee DH, Lee JY. et al. Assessment of hepatic steatosis by using attenuation imaging: a quantitative, easy-to-perform ultrasound technique. Eur Radiol 2019; 29: 6499-6507 DOI: 10.1007/s00330-019-06272-y. (PMID: 31175413)
• 6 Aubin B, Denys A, Lafortune M. et al. Focal sparing of liver parenchyma in steatosis: role of the gallbladder and its vessels. J Ultrasound Med 1995; 14: 77-80 DOI: 10.7863/jum.1995.14.2.77. (PMID: 8568966)
• 7 Kester NL, Elmore SG. Focal hypoechoic regions in the liver at the porta hepatis: prevalence in ambulatory patients. J Ultrasound Med 1995; 14: 649-652 DOI: 10.7863/jum.1995.14.9.649. (PMID: 7500427)
• 8 Kratzer W, Akinli AS, Bommer M. et al. Prevalence and risk factors of focal sparing in hepatic steatosis. Ultraschall Med 2010; 31: 37-42 DOI: 10.1055/s-0028-1109894. (PMID: 20157869)
• 9 Matsui O, Kadoya M, Takahashi S. et al. Focal sparing of segment IV in fatty livers shown by sonography and CT: correlation with aberrant gastric venous drainage. AJR Am J Roentgenol 1995; 164: 1137-1140 DOI: 10.2214/ajr.164.5.7717220. (PMID: 7717220)
• 10 Terayama N, Matsui O, Tatsu H. et al. Focal sparing of fatty liver in segment II associated with aberrant left gastric vein. Br J Radiol 2004; 77: 150-152 DOI: 10.1259/bjr/86102770. (PMID: 15010390)
• 11 Valls C, Iannacconne R, Alba E. et al. Fat in the liver: diagnosis and characterization. Eur Radiol 2006; 16: 2292-2308 DOI: 10.1007/s00330-006-0146-0. (PMID: 16477402)
• 12 Chalasani N, Younossi Z, Lavine JE. et al. The diagnosis and management of nonalcoholic fatty liver disease: practice guidance from the American Association for the Study of Liver Diseases. Hepatology 2018; 67: 328-357 DOI: 10.1002/hep.29367. (PMID: 28714183)
• 13 Hamaguchi M, Kojima T, Itoh Y. et al. The severity of ultrasonographic findings in nonalcoholic fatty liver disease reflects the metabolic syndrome and visceral fat accumulation. Am J Gastroenterol 2007; 102: 2708-2715 DOI: 10.1111/j.1572-0241.2007.01526.x. (PMID: 17894848)
• 14 Saverymuttu SH, Joseph AE, Maxwell JD. Ultrasound scanning in the detection of hepatic fibrosis and steatosis. Br Med J (Clin Res Ed) 1986; 292: 13-15 DOI: 10.1136/bmj.292.6512.13. (PMID: 3080046)
• 15 Charatcharoenwitthaya P, Lindor KD. Role of radiologic modalities in the management of nonalcoholic steatohepatitis. Clin Liver Dis 2007; 11: 37-54 DOI: 10.1016/j.cld.2007.02.014. (PMID: 17544971)
• 16 Couinaud C. Liver lobes and segments: notes on the anatomical architecture and surgery of the liver. Presse Med 1954; 62: 709-712 (PMID: 13177441)
• 17 Taylor KJ, Riely CA, Hammers L. et al. Quantitative US attenuation in normal liver and in patients with diffuse liver disease: importance of fat. Radiology 1986; 160: 65-71 DOI: 10.1148/radiology.160.1.3520657. (PMID: 3520657)
• 18 Tada T, Iijima H, Kobayashi NT. et al. Usefulness of attenuation imaging with an ultrasound scanner for the evaluation of hepatic steatosis. Ultrasound Med Biol 2019; 45: 2679-2687 DOI: 10.1016/j.ultrasmedbio.2019.05.033. (PMID: 31277922)
• 19 Jeon SK, Lee JM, Joo I. et al. Prospective evaluation of hepatic steatosis using ultrasound attenuation imaging in patients with chronic liver disease with magnetic resonance imaging proton density fat fraction as the reference standard. Ultrasound Med Biol 2019; 45: 1407-1416 DOI: 10.1016/j.ultrasmedbio.2019.02.008. (PMID: 30975533)
• 20 Jesper D, Klett D, Schellhaas B. et al. Ultrasound-based attenuation imaging for the non-invasive quantification of liver fat—a pilot study on feasibility and inter-observer variability. IEEE J Transl Eng Health Med 2020; 8: 1800409 DOI: 10.1109/JTEHM.2020.3001488. (PMID: 32617199)
• 21 Kaafarani N. Liver Package Aplio i800. Canon Medical Systems, Tochigi; Japan: 2018
• 22 Yoo J, Lee JM, Joo I. et al. Reproducibility of ultrasound attenuation imaging for the noninvasive evaluation of hepatic steatosis. Ultrasonography 2020; 39: 121-129 DOI: 10.14366/usg.19034. (PMID: 31693842)
• 23 Dioguardi Burgio M, Ronot M, Reizine E. et al. Quantification of hepatic steatosis with ultrasound: promising role of attenuation imaging coefficient in a biopsy-proven cohort. Eur Radiol 2020; 30: 2293-2301 DOI: 10.1007/s00330-019-06480-6.
• 24 Kaltenbach TE, Engler P, Kratzer W. et al. Prevalence of benign focal liver lesions: ultrasound investigation of 45,319 hospital patients. Abdom Radiol (NY) 2016; 41: 25-32 DOI: 10.1007/s00261-015-0605-7. (PMID: 26830608)
• 25 Kammen BF, Pacharn P, Thoeni RF. et al. Focal fatty infiltration of the liver: analysis of prevalence and CT findings in children and young adults. AJR Am J Roentgenol 2001; 177: 1035-1039 DOI: 10.2214/ajr.177.5.1771035. (PMID: 11641164)
• 26 McPherson S, Hardy T, Henderson E. et al. Evidence of NAFLD progression from steatosis to fibrosing-steatohepatitis using paired biopsies: implications for prognosis and clinical management. J Hepatol 2015; 62: 1148-1155 DOI: 10.1016/j.jhep.2014.11.034. (PMID: 25477264)
• 27 Ajmera V, Park CC, Caussy C. et al. Magnetic resonance imaging proton density fat fraction associates with progression of fibrosis in patients with nonalcoholic fatty liver disease. Gastroenterology 2018; 155: 307-310.e2 DOI: 10.1053/j.gastro.2018.04.014. (PMID: 29660324)
• 28 Bhatnagar G, Sidhu HS, Vardhanabhuti V. et al. The varied sonographic appearances of focal fatty liver disease: review and diagnostic algorithm. Clin Radiol 2012; 67: 372-379 DOI: 10.1016/j.crad.2011.10.020. (PMID: 22265856)
• 29 Hamer OW, Aguirre DA, Casola G. et al. Fatty liver: imaging patterns and pitfalls. Radiographics 2006; 26: 1637-1653 DOI: 10.1148/rg.266065004. (PMID: 17102041)
• 30 Wu S, Tu R, Zheng E. et al. Findings and implications of focal fatty sparing of the liver at follow-up: a preliminary study based on sonography, computed tomography, and magnetic resonance imaging. J Ultrasound Med 2013; 32: 1695-1702 DOI: 10.7863/ultra.32.10.1695. (PMID: 24065249)