A329 ROLE OF AMPULLARY BIOPSY IN AUTOIMMUNE PANCREATITIS
Bibliographic record
Abstract
Autoimmune pancreatitis (AIP) is a rare disorder of the pancreas with a prevalence and incidence of 4.6/100,000 & 1.4/100,000 population in Japan. Clinical presentation includes abdominal pain (65%), jaundice (62%), weight loss (42%), with approximately 85% of patients having abnormalities of the pancreas on imaging. The Mayo Clinic HISORt criteria is most commonly used for diagnosis. However, often the diagnosis is ambiguous and can lead to significantly morbid surgical resections for a disease that is responsive to immunosuppression. Therefore, endoscopic ampullary biopsies have been proposed as an adjunct to the diagnosis. There have relatively been a few studies looking at the diagnostic yield of ampullary biopsies in AIP, most reporting a high specificity and a sensitivity of 50–60% (i) To correlate ampullary biopsy specimens on patients diagnosed with AIP via HISORt criteria. We aim to determine the diagnostic yield for ampullary biopsies in AIP in our cohort of patients. We believe ampullary biopsies provide valuable diagnostic information in AIP and should be used as an adjunct in the diagnostic work up for AIP. (ii) We also aim to correlate positive ampullary biopsies with abnormalities in serum IgG-4 levels (normal range 0.05 – 1.25 g/L) We conducted a retrospective chart review of patients with autoimmune pancreatitis fulfilling the HISORt criteria, seen at the Vancouver General Hospital, Vancouver BC, from January 1, 2011 till July 31, 2016, who also had ampullary biopsies taken endoscopically. A positive biopsy, as defined in the literature, was more than 10 IgG-4 Immunohistochemically (IHC) positive plasma cells per 1 high power field (HPF) at a magnification of x400. We also collected serum IgG-4 values for this cohort of patients To date, there have been 20 patients, mean age of 62 with 80% males, with AIP as per HISORt criteria, that have also had ampullary biopsies taken. Out of these, only 6 met the definition for a positive ampullary biopsy, giving a diagnostic yield of 30%, whereas the rest did not meet a histological diagnosis of AIP on ampullary biopsies. Out of the 20 patients, 50% (10) had elevated serum IgG-4 levels. All patients with a positive ampullary biopsy had an elevated serum IgG-4 level Ampullary biopsies, if positive, provide a specific diagnostic adjunct in patients with presumed Autoimmune Pancreatitis as per the HISORt criteria. However, this is true only in approximately one third of such patients, as per this retrospective chart review. This is similar to prior studies. Additionally, we found serum IgG-4 levels only elevated in half of our cohort of patients with AIP. Serum IgG-4 levels however, correlate strongly with positive ampullary biopsies. More prospective studies will be needed to further confirm these findings None
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".