Comparison of diagnostic accuracy and interpretation times for a standard and an advanced 3D visualisation technique in CT colonography.
OBJECTIVE
To compare the diagnostic accuracy of a standard bi-directional, three-dimensional (3D) CT colonography (CTC) fly-through (standard view, SV) with a unidirectional, 3D unfolding technique (panoramic view, PV).


METHODS
150 consecutive endoscopically-validated CTC patient datasets were retrospectively reviewed twice by two expert radiologists: first, with bidirectional SV, second, after 6-15 months, with unidirectional PV. Per-polyp sensitivities, percentage of visualised colonic mucosa, and reading times were calculated for both 3D visualisations. Results were tested for statistical significance by equivalence analysis for paired proportions and Student's paired t-test.


RESULTS
In 81 patients, 236 polyps (101 adenomas, 135 non-adenomas) were detected. Sensitivities for polyps ≤5 mm, 6-9 mm and ≥10 mm were 60.1% (113/188), 92.9% (26/28) and 95.0% (19/20) with bidirectional SV, and 60.6% (114/188), 96.4% (27/28) and 95.0% (19/20) with unidirectional PV. Overall sensitivity for adenomas was 86.1% and 84.2% for SV and PV. Both methods provided equivalent polyp detection, with an equivalence limit set at 5%. PV and SV visualised 98.9 ± 1.1% (97.0-99.9%) and 96.2 ± 2.3% (91.4-98.8%) of the colonic mucosa (p > 0.05). Mean interpretation time decreased from 14.6 ± 2.5 (9.2-22.8) minutes with SV to 7.5 ± 3.2 (5.0-14.4) using PV (p < 0.0001).


CONCLUSIONS
3D CTC interpretation using unidirectional PV is equally as accurate, but significantly faster than an interpretation based on bidirectional SV.
Mang
Thomas
T
Department of Radiology, Medical University of Vienna, Waehringer Guertel, 18-20, 1090, Vienna, Austria. thomas.mang@meduniwien.ac.at
Kolligs
Frank T
FT
Schaefer
Claus
C
Reiser
Maxmilian F
MF
Graser
Anno
A
D001317:Austria / Q000453:epidemiology; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D003111:Colonic Polyps / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D023881:Colonography, Computed Tomographic / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015995:Prevalence; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016526:Workload / Q000706:statistics & numerical data*