Improved tissue sections for medical liver biopsies: a comparison of 16 vs 18 g biopsy needles using digital pathology

Abstract

Background Most medical liver biopsies in the UK are now taken in radiology departments using 18 g biopsy needles. Subjectively, the resulting biopsies are narrow and fragile. Aim To compare the quality of liver biopsy tissue sections obtained from 16 and 18 g biopsy needles. Method Fifty consecutive routine medical liver biopsies obtained with 16 and 18 g needles, processed identically in the same laboratory, were measured using digital pathology software. We recorded their fragmentation, length, width, area and number of portal tracts. Results Biopsies obtained with 16 g needles more often resulted in an intact core in tissue sections than those with 18 g needles (71% vs 24%, p<0.001) and were significantly wider (average width of tissue 0.88 vs 0.53 mm, p<0.001). The average total area of tissue per pass was 11.38 mm2 compared with 8.34 mm2 (p<0.001). The number of complete portal tracts per length of biopsy was very variable, but double for 16 vs 18 g biopsies. Routinely taking two passes with the 18 g needle compensated for the reduced area, but the resulting liver in tissue sections was fragmented and distorted. Conclusions Our results support the routine use of 16 g rather than 18 g biopsy needles for routine ultrasound-guided medical liver biopsies. A second pass should be considered if the first biopsy core is short, especially for investigation of disease stage.

Guidelines on the use of liver biopsy in clinical practice from the British Society of Gastroenterology, the Royal College of Radiologists and the Royal College of Pathology

“… 67 76 A 16 G needle biopsy specimen was found to be intact significantly more often than with 18 G biopsy needles (71% compared with 24%) and to contain double the number of complete portal tracts per length of biopsy. 76 Based on the above standard of an adequate biopsy being 20 mm in length and including >10 portal tracts, inadequate <10 mm and <6 portal tracts, with intermediate samples described as 'compromised', one audit showed an adequate rate of 24.7% and inadequate of 21.9% in biopsies between 2008 and 2011, which represented a significant improvement on pre-2008 figures. 68 This study corroborated the effect of biopsy size on fibrosis stage, with cirrhosis diagnosed in 6.5%, 11.0% and 14.6% of inadequate, compromised and adequate biopsies, respectively, while the proportion reported as no fibrosis was 27.1%, 12.1% and 7.3%.…”

Society of Interventional Radiology Quality Improvement Standards on Percutaneous Needle Biopsy in Adult and Pediatric Patients

“…20-25 mm long and contain ! 11 complete portal triads (102)(103)(104)(105)(106). Despite the lack of a clear consensus, most available literature supports the use of 16-gauge needles over 18-gauge needles for nonfocal liver biopsy (107).…”

Consensus recommendations for histological criteria of autoimmune hepatitis from the International AIH Pathology Group

“…27 Even more important seems to be the diameter of a liver biopsy which is more relevant for the number of complete portal tracts than the length. 28 Besides detailing the adequacy of a given biopsy specimen for diagnostic evaluation, the pathology report should also provide a systematic evaluation of all histological landmarks of the liver lobule (eg portal tracts, parenchyma, sinusoids, central veins) and include a comment on the presence and severity of fibrosis as a manifestation of chronic liver injury. In the context of an acute presentation and histological features of predominantly lobular hepatitis, the presence and quality of established fibrosis may favour a diagnosis of AIH over other causes of acute hepatitis (eg virus, drugs), which are less likely to have underlying fibrosis.…”