Variability in mesothelioma tumor response classification.
OBJECTIVE
The objective of our study was to evaluate observer variability in the measurement of temporal change in mesothelioma tumor thickness and in the resulting tumor response classification from CT scans. In addition, the performance of a semiautomated measurement method was evaluated.


METHODS
Four observers individually used an interface that displayed two serial CT scans from the same patient to measure mesothelioma tumor thickness on the follow-up CT scans of 22 patients based on baseline scan measurements. During one session, observers acquired measurements on the follow-up scans based on written reports of baseline scan measurements; in another session, baseline scan measurements were superimposed on the baseline scan for direct visual comparison. Follow-up scan measurements also were obtained from a semiautomated method. Measurement variability and tumor response classification concordance were evaluated for manual measurements acquired in both modes and for semiautomated measurements.


RESULTS
Although only a small increase in tumor response classification concordance rate was obtained with the visual approach (84.8%) relative to the more standard written-report approach (82.6%), the actual measurements acquired by observers were statistically significantly different between the two approaches (p = 0.03). Both the semiautomated measurements and the resulting tumor response classifications were consistent with manual measurements.


CONCLUSIONS
The presentation of baseline scan tumor measurements affects measurements acquired on follow-up scans and could influence tumor response classification. The potential utility of semiautomated tumor thickness measurements was shown in the context of measuring tumor response.
Armato
Samuel G
SG
Department of Radiology, The University of Chicago, 5841 S Maryland Ave., Chicago, IL 60637, USA. s-armato@uchicago.edu
Ogarek
Joseph L
JL
Starkey
Adam
A
Vogelzang
Nicholas J
NJ
Kindler
Hedy L
HL
Kocherginsky
Masha
M
MacMahon
Heber
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008654:Mesothelioma / Q000145:classification* / Q000000981:diagnostic imaging* / Q000473:pathology; D008875:Middle Aged; D015588:Observer Variation; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*