[Multi-slice spiral CT of the abdomen in oncological patients: influence of table support and detector configuration on image quality and radiation exposure].
OBJECTIVE
To evaluate the image quality and radiation exposure of different spiral CT scanning parameters for routine staging examination of the abdomen in oncologic patients using a multi-slice CT scanner.


METHODS
Examination of 40 patients in 4 groups on a multi-slice CT scanner (Somatom VolumeZoom, Siemens AG, Forchheim). Functional detector width (4 x 2.5, 4 x 5 mm) and pitch (table feed in relation to collimated slice width) were varied (3 and 5). Tube voltage (120 kV), effective tube current (160 mAs), slice-thickness (6 mm), increment (4 mm), kernel (B 30), and contrast injection parameters were kept constant. Axial images were assessed by three radiologists regarding delineation of anatomic structures, artifacts, and overall image quality.


RESULTS
Significantly reduced image quality especially due to artifacts was observed using a 5 mm detector configuration with a pitch of 5 (scan time 9 sec). Image quality was rated best for a 2.5 mm detector configuration with a pitch of 3 and a scan time of 28 sec. The effective dose was independent of the pitch. However, the mean effective dose was 9% higher using the smaller detector configuration (9.9 mSv vs 10.9 mSv).


CONCLUSIONS
For routine staging CT of the abdomen use of a 4 x 2.5 mm detector configuration with a pitch between 3 and 5 is recommended. A 4 x 5 mm detector configuration using overlapping data acquisition can also be recommended, but additional thin slice reformations are not possible.
Wessling
J
J
Institut für Klinische Radiologie, Universitätsklinikum Münster. weslingj@uni-muenster.de
Fischbach
R
R
Ludwig
K
K
Juergens
K U
KU
Schaller
S
S
Fallenberg
E M
EM
Lenzen
H
H
Heindel
W
W
D000008:Abdominal Neoplasms / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011860:Radiography, Abdominal; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods*