Determining the Variability of Lesion Size Measurements from CT Patient Data Sets Acquired under "No Change" Conditions.
OBJECTIVE
To determine the variability of lesion size measurements in computed tomography data sets of patients imaged under a "no change" ("coffee break") condition and to determine the impact of two reading paradigms on measurement variability.


METHODS
Using data sets from 32 non-small cell lung cancer patients scanned twice within 15 minutes ("no change"), measurements were performed by five radiologists in two phases: (1) independent reading of each computed tomography dataset (timepoint): (2) a locked, sequential reading of datasets. Readers performed measurements using several sizing methods, including one-dimensional (1D) longest in-slice dimension and 3D semi-automated segmented volume. Change in size was estimated by comparing measurements performed on both timepoints for the same lesion, for each reader and each measurement method. For each reading paradigm, results were pooled across lesions, across readers, and across both readers and lesions, for each measurement method.


RESULTS
The mean percent difference (±SD) when pooled across both readers and lesions for 1D and 3D measurements extracted from contours was 2.8 ± 22.2% and 23.4 ± 105.0%, respectively, for the independent reads. For the locked, sequential reads, the mean percent differences (±SD) reduced to 2.52 ± 14.2% and 7.4 ± 44.2% for the 1D and 3D measurements, respectively.


CONCLUSIONS
Even under a "no change" condition between scans, there is variation in lesion size measurements due to repeat scans and variations in reader, lesion, and measurement method. This variation is reduced when using a locked, sequential reading paradigm compared to an independent reading paradigm.
David Geffen School of Medicine at UCLA, Los Angeles, CA, USA. Electronic address: mmcnittgray@mednet.ucla.edu.
Michael F
MF
McNitt-Gray
David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
Grace Hyun
GH
Kim
Columbia University Medical Center, New York, NY, USA.
Binsheng
B
Zhao
Columbia University Medical Center, New York, NY, USA.
Lawrence H
LH
Schwartz
Pixel Med Publishing, LLC, Bangor, PA, USA (formerly with Core Lab Partners, Inc, Princeton, NJ).
David
D
Clunie
Janssen Pharmaceutical Research and Development (formerly with Core Lab Partners, Inc, Princeton, NJ), Titusville, NJ, USA.
Kristin
K
Cohen
Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA.
Nicholas
N
Petrick
The Image-Quality Measurement Consultancy, Gaithersburg, MD, USA (formerly with National Institute of Standards and Technology, Gaithersburg, MD).
Charles
C
Fenimore
National Institute of Standards and Technology, Gaithersburg, MD, USA.
Z Q John
ZQ
Lu
Elucid Bioimaging Inc, Wenham, MA, USA.
Andrew J
AJ
Buckler