One More Problem with HIDA Scans

A recent case study (A Adeyemi et al. J Pediatr 2020; 220: 245-8) provides information on 6 infants with a subsequent diagnosis of biliary atresia who had HIDA scans which reported excretion.

Methods: HIDA scans from 1992-2012 were reviewed from CHOP, this included 223 infants up to 4 months of age.

Key findings:

  • While there were six cases with HIDA scans that showed excretion into the bowel, none of these infants had truly normal HIDA scans.
  • 4 of the 6 patients had excretion qualified as slight, mild, or subtle and faint.
  • 5 of the 6 patients did not have the gallbladder visualized on HIDA.

Commentary:

  • HIDA scans are well-known to have a high sensitivity but a low specificity for biliary atresia (even with pretreatment choleretic agents). Liver biopsies have a higher diagnostic accuracy.
  • Since biliary atresia is a progressive disease, some excretion on HIDA does not exclude the diagnosis.  Though, age at HIDA was not a significant variable in this small series.

My takes:

  • Don’t rely too much on any test, including HIDA scans.  Equivocal findings need to be reported as such.
  • Fortunately, MMP-7 has emerged as another quick way with good (not perfect) specificity for biliary atresia.
  • Another related caveat is to look carefully at ultrasounds in this age group.  Often a small or retracted gallbladder is overlooked and could be an important clue to the diagnosis of biliary atresia.

Related blog posts:

Rhododendron Flowers (Spring 2020)

Quirky HIDA Study Shows That HIDA Scans Not Too Helpful

As noted in a previous post, Biliary Dyskinesia –“Only in America” | gutsandgrowth, gallbladder dykinesia is a quite dubious diagnosis.  A recent pediatric study (PM Jones et al. JPGN 2016; 63: 71-75) adds to the uncertainty.

This study utilized a large database for a retrospective review of HIDA scans in patients <22 years.  In a group of 2558 patients, 310 patients had a full-text gallbladder pathology report paired with HIDA scan. The majority of these HIDA scans (64.5%) were performed in teenage Caucasian girls.  Key finding:

  • Gallbladder ejection fraction (GBEF) did not correlate with the presence of gallbladder pathology.  The Odd Ratio (OR) for cholecystitis with EF of 16-34 was 0.98.
  • The majority had at least microscopic pathology: 71.6% had microscopic cholecystitis

The authors indicate that other studies have shown that the diagnosis of gallbladder dyskinesia is controversial “because some point to the strong placebo effect of a surgical intervention, as well as the finding that patients who were observed for a year or more had similar symptom improvement  compared with those who had an operation.” [J Pediatric Surg 2006; 41: 1894-8]

Ultimately, the utility of HIDA scans can only be addressed with randomized prospective studies. Perhaps, these studies will show that HIDA scans are not predictive of who needs a cholecystectomy.

My take: It is interesting that pathology did not correlate with HIDA results.  However, the bigger question is whether abnormal gallbladder function, as assessed by HIDA, triggers symptoms that merit cholecystectomy. This is not addressed by this study.

Beach Art

Beach Art