programma & abstracts - Nederlandse Vereniging voor Radiologie

6
programma abstracts & abstracts
Sessie 6
Abdominale radiologie 2
Vrijdag 30 september, 10.45 - 12.15 uur
O6.1
EVALUATION OF A STANDARDIZED CT
COLONOGRAPHY TRAINING PROGRAM IN
NOVICE READER
M.H. Liedenbaum 1 , S. Bipat 1 , P.M.M. Bossuyt 1 ,
R.S. Dwarkasing 2 , M.C. de Haan 1 , R.J. Jansen 1 ,
D. Kauffman 1 , C. van der Leij 1 , M.S. de Lijster 1 , C.C. Lute 1 ,
M.P. van der Paardt 1 , M.G. Thomeer 2 , I.J.A. Zijlstra 1 ,
J. Stoker 1
1
Academisch Medisch Centrum, Amsterdam
2
Erasmus Medisch Centrum, Rotterdam
Purpose: To determine how many CT colonography (CTC) training
examinations have to be evaluated by novice readers to
obtain an adequate level of competence in polyp detection.
Methods: Informed consent was obtained from all participants.
Six physicians (one radiologist, three radiology
residents, two researchers) and three technicians completed
a CTC training program. 200 CTC’s with colonoscopic verification
were selected from a research database, with 100
CTC’s with at least one polyp ≥6mm. After a lecture session
and an individual hands-on training, CTC reading was done
individually with immediate feedback of the colonoscopy
outcome. The increase in per-polyp sensitivity was calculated
for four sets of 50 CTC’s for lesions ≥6mm. Using logistic
regression analyses, the number of CTC’s to reach 90%
sensitivity for lesions ≥6mm was estimated. Reading times
were registered.
Results: The average per-polyp sensitivity for lesions
≥6mm was 76% (207/270) in the first set of 50 CTC’s,
77% (262/342) in the second set (p=0.96 vs. first set), 80%
(310/387) in the third set (p=0.67 vs. first set) and 91%
(261/288) in the fourth set (p=0.018). The estimated number
of CTC’s to be evaluated to reach a sufficient sensitivity for
lesions ≥6mm was 164. Six of the nine readers reached
this level of competence within 175 CTC’s. Reading times
decreased significantly from the first 50 CTC’s to the second
50 CTC’s for 6 readers.
Conclusions: Novice CT colonography readers obtained a
sensitivity equal to that of experienced readers after practicing
on average 164 CTC studies.
O6.2
THE FEASIBILITY OF TRAINING
RADIOLOGIC TECHNOLOGISTS IN
TRIAGING CT-COLONOGRAPHY FOR
EXTRACOLONIC FINDINGS
T.N. Boellaard, C.Y. Nio, P.M. Bossuyt, J. Stoker
Academisch Medisch Centrum, Amsterdam
Purpose: Cost-effectiveness is important for the implementation
of CT-colonography as a screening tool for colorectal
cancer. Radiologists’ reading time contributes substantially
to CT-colonography costs. Therefore we evaluate the
feasibility of radiologic technologists in triaging screening
CT-colonography for extracolonic findings.
Method and materials: Eight technologists participated in
a training program and subsequently reported extracolonic
findings in 280 CT-colonography exams. The dataset
contained 86 possibly (E3) and 30 probably important (E4)
findings (C-RADS). The first and last 40 cases were identical
examination cases. Feedback was given after each case
from reference standard (the consensus read by two radiologists),
except for the examination cases. Technologists
reported lesion location and characteristics, C-RADS classification,
need for a radiologist’s read and reading time.
We constructed learning curves for correct scan and lesion
triaging using a moving average technique.
Results: For the final exam 70% of scans with E3 or E4
findings were correctly triaged, while 30.5% of scans
without E3 or E4 findings were incorrectly triaged. For the
final exam technologists correctly identified and classified
64.4%(67/104) of E3 and 67.5%(27/40) of E4 findings.
This is an improvement, compared to the first exam, of
33.6%(p0.05). The learning curve for
E3 and E4 findings combined did not reach a plateau after
280 cases. The technologists’ average reading time decreased
from 11:51 to 4:13 minutes(p