Detection of pulmonary metastases with multi-detector row CT scans of 5-mm nominal section thickness: autopsy lung study.
OBJECTIVE
To determine the effect of changing pitch and collimation on depiction of pulmonary metastases on scans of 5-mm section thickness obtained with multi-detector row computed tomography (CT) compared with those obtained with single-detector row CT.


METHODS
In five autopsy lungs, 1,013 metastatic 0.5-30.0-mm nodules were detected at helical CT with 1-mm collimation and histopathologically diagnosed as metastases. Each nodule was numbered, and its localization was recorded as the standard for subsequent studies. Four types of scans of 5-mm section thickness were obtained with multi-detector row CT and four sets of helical pitch and table speed, respectively, as follows: set A, 3:1 and 7.5 mm per rotation; set B, 6:1 and 15 mm per rotation; set C, 6:1 and 30 mm per rotation; set D, conventional and 5-mm interval. Conventional helical CT scans (set E) were obtained with 5-mm collimation at single-detector row CT. Two independent observers evaluated the five sets of CT scans.


RESULTS
Acquisition times for sets A-D, respectively, were 1.9, 3.8, 7.5, and 1.5 times faster than they were for set E. The mean numbers of detected nodules were 671 (66%) in set A, 661 (65%) in set B, 678 (67%) in set C, 654 (65%) in set D, and 656 (65%) in set E; there was no significant difference in the number of detected nodules among the five sets (P =.997, McNemar test and Bonferroni equation).


CONCLUSIONS
Regardless of varying pitch or detector collimation, multi- and single-detector row CT scans obtained with 5-mm section thickness have almost the same ability to depict pulmonary metastases and are equivalent.
Kozuka
Takenori
T
Department of Radiology, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan. koz@radiol.med.osaka-u.ac.jp
Johkoh
Takeshi
T
Hamada
Seiki
S
Naito
Hiroaki
H
Tomiyama
Noriyuki
N
Koyama
Mitsuhiro
M
Mihara
Naoki
N
Honda
Osamu
O
Nakamura
Hironobu
H
Kudo
Masayuki
M
D001344:Autopsy; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D036542:Tomography, Spiral Computed / Q000379:methods*