B Wildman-Tobriner et al. Gastoenterol 2018; 155: 1428-35. This retrospective study which pooled data from 3 phase 2a trials with 370 subjects with nonalcoholic fatty liver disease (NAFLD) found that MRI iwth proton density fat fraction (PDFF) “did not accurately identify patients with NAS ≥4 (AUROC – 0.72) or fibrosis stage ≥3 (AUROC =0.66).” Thus, this study indicates that currently liver histology remains the gold standard to determine severity of liver damage in paitents with NAFLD.
P Nahon et al. Gastroenterol 2018; 155: 1436-1450. This study looks closer at whether direct-acting antivirals (DAA) for hepatitis C could increase the risk of hepatocellular carcinoma (HCC) in patients (n=1270) with cirrhosis. The authors found that the crude 3-year cumulative incidence of HCC were 5.9% in the DAA and 3.1% in the SVR-IFN group. However, after Cox analysis, “we found no statistically significant increase in risk of HCC associated with DAA use (HR 0.89).” The authors indicated that patient characteristics (age, diabetes, reduced liver function) and lower screening intensity were the reasons for the increased crude rates of HCC.
What this latest study suggests, in the context of other studies, is that if people can’t shop for elective M.R.I.s, there’s hardly a chance they are going to do so with other health care procedures that are more complicated and variable.
Even if 40 percent of health care is shoppable, people are not shopping. What seems likelier to work is doing more to influence what doctors advise.
For example, we could provide physicians with price, quality and distance information for the services they recommend. Further, with financial bonuses, we could give physicians (instead of, or in addition to, patients) some incentive to identify and suggest lower-cost care.
Leaving decisions to patients, and making them spend more of their own money, doesn’t work.
A recent retrospective single-center study (J Satkunasingham et al. Liver Transplantation 2018; 24: 470-77) shows that MRI is a good tool to assess hepatic steatosis. In total there were 144 liver donor candidates; a subset of 32 underwent liver biopsy.
When examining magnetic resonance spectroscopy (MRS) and MRI -proton pump density fat fraction (PDFF), the authors found that MRS-PDFF and MRI-PDFF had 95% and 100% negative predictive value in identifying patients with clinically significant histologic steatosis (≥10%).
The associated editorial by James Trotter (pg 457-58) makes several important points:
Currently living donor transplantation in the U.S. accounts for 4% of all transplants
In his center (and most centers), protocol biopsy are not required prior to liver donation. The main indications for donor liver biopsy are biochemical dysfunction or steatosis on imaging studies.
My take (borrowed from editorial): “Noninvasive estimation of hepatic steatosis is sufficiently accurate to forgo liver biopsy in most donors, although ultimately this decision will continue to rest with the individual center.”
C Sikavi et al. Hepatology 2018; 67: 847-57. This systematic review highlights that the combination of hepatitis C virus (HCV) infection and HIV infection is no longer a difficult-to-treat population with the implementation of direct-acting antivirals (DAAs). There are similar sustained virologic responses (SVRs) among those with and those without HIV. In clinical trials, patients with combined HCV-HIV had SVRs of 93.5-98% with DAA treatment; “real-world cohorts” had SVRs of 90.9%-98%.
MS Middleton et al. Hepatology 2018; 67: 858-72. Using data from the prospective CyNCh trial (cysteamine for NAFLD), the authors examined MRIs for diagnostic accuracy among 169 enrolled children. In this group, 110 (65%) and 83 (49%) had MRI and liver biopsy at baseline. MRI-PDFF (proton density fat fraction) was able to classify grade 1 steatosis from grade 2-3 steatosis with area under receiving operator characteristic curve of 0.87. Thus, this study shows MRI-estimated PDFF has high diagnostic accuracy.
G Mieli-Vergani et al. JPGN 2018; 66: 345-60. Position paper for Pediatric Autoimmune Liver Disease (AIH, ASC, de novo AIH after liver transplantation). This is a very useful review. A couple of pointers from the authors:
“Present experience with budesonide as the first-line treatment is limited and does not appear to offer clear clinical advantage over the standard treatment”[prednisone]
Fecal calprotectin should be obtained to evaluate for IBD in patients with autoimmune liver disease, “even in asymptomatic children.”
JM Cotter et al. JPGN 2018; 66: 227-33. This retrospective study with 39 patients with primary sclerosing cholangitis (PSC) showed a lack of correlation between liver tests and fibrosis at presentation. Average age of PSC diagnosis was 11.2 years, 74% had inflammatory bowel disease and 51% had autoimmune hepatitis. Related blog post: Big Pediatric PSC Study (with 781 children)
A recent study (JB Schwimmer et al. Hepatology 2015; 1887-95, editorial Vos MB, pages 1779-80) examines the accuracy of magnetic resonance imaging (MRI) compared with liver histology in children with nonalcoholic fatty liver disease.
This prospective validation study enrolled 174 children with a mean age of 14 years. The MRI estimated the liver proton density fat fraction (PDFF).
Liver MRI-PDFF correlated with steatosis grade; the correlation was particularly strong at high and low end values. Thus, a very low MRI-PDFF was highly likely to predict a steatosis grade 0 or 1 while a very high value corresponded to high steatosis levels.
Liver MRI-PDFF was weaker in children with stage 2-4 fibrosis than in children with no fibrosis
The editorial notes that this study “is one of hundreds now published in the literature on MRI and NAFLD…The superiority of MR-based methods…over ultrasound is clear. The question is why are we still ordering abdominal ultrasounds to diagnose NAFLD in children?” The barriers for usage of MRI include cost, potential sedation, and nonuniform methods for MRI usage.
The paper conclude that “MRI is not yet sufficient to replace liver biopsy in children.” The editorial also indicates that the MRI era is fast approaching but not viable today.
Take-home point: Due to the huge numbers of patients with pediatric NAFLD, MRI remains a terrific area for research but remains problematic in clinical practice. Given the expense of MRI, until its use can reduce liver biopsies or improve management, its role is likely to remain limited.
“In this study, the researchers compared a new MRI technique to the standard liver biopsy method of assessing fat in the liver. To do this, the team enrolled 174 children who were having liver biopsies for clinical care. For each patient, the team performed both MRI-estimated PDFF and compared the results to the standard pathology method of measuring fat on a liver biopsy.”
Screenshot from MedicalNewsToday
“The team found a strong correlation between the amount of liver fat as measured by the new MRI technique and the grade of liver fat determined by pathology. This is an important step towards being able to use this technology for patients. Notably, the correlation was influenced by both the patient’s gender and the amount of scar tissue in the liver. The correlation between the two techniques was strongest in females and in children with minimal scar tissue.”
“Depending on how the new MRI technology is used, it could correctly classify between 65 and 90 percent of children as having or not having fatty liver tissue.”
“… However, further refinements will be needed before this or any other MRI technique can be used to diagnose NAFLD in an individual child.“