[Pediatric bowel MRI--accelerated parallel imaging in a single breathhold].
OBJECTIVE
To compare highly accelerated parallel MRI of the bowel with conventional balanced FFE sequences in children with inflammatory bowel disease (IBD).


METHODS
20 children with suspected or proven IBD underwent MRI using a 1.5 T scanner after oral administration of 700 -1000 ml of a Mannitol solution and an additional enema. The examination started with a 4-channel receiver coil and a conventional balanced FFE sequence in axial (2.5 s/slice) and coronal (4.7 s/slice) planes. Afterwards highly accelerated (R = 5) balanced FFE sequences in axial (0.5 s/slice) and coronal (0.9 s/slice) were performed using a 32-channel receiver coil and parallel imaging (SENSE). Both receiver coils achieved a resolution of 0.88 x 0.88 mm with a slice thickness of 5 mm (coronal) and 6 mm (axial) respectively. Using the conventional imaging technique, 4 - 8 breathholds were needed to cover the whole abdomen, while parallel imaging shortened the acquisition time down to a single breathhold. Two blinded radiologists did a consensus reading of the images regarding pathological findings, image quality, susceptibility to artifacts and bowel distension. The results for both coil systems were compared using the kappa-(kappa)-coefficient, differences in the susceptibility to artifacts were checked with the Wilcoxon signed rank test. Statistical significance was assumed for p = 0.05.


RESULTS
13 of the 20 children had inflammatory bowel wall changes at the time of the examination, which could be correctly diagnosed with both coil systems in 12 of 13 cases (92 %). The comparison of both coil systems showed a good agreement for pathological findings (kappa = 0.74 - 1.0) and the image quality. Using parallel imaging significantly more artifacts could be observed (kappa = 0.47) without impairing the diagnostic impact. The comparison of the bowel distension showed no significant differences.


CONCLUSIONS
The highly accelerated parallel MRI using the SENSE technique and a 32-channel surface coil enables the examination of the entire bowel in a single breathhold without relevant restrictions in image quality and diagnostic impact.
Hohl
C
C
Klinik für Radiologische Diagnostik, UK Aachen. hohl@rad.rwth-aachen.de
Honnef
D
D
Krombach
G
G
Ocklenburg
C
C
Mühlenbruch
G
G
Wenzl
T G
TG
Günther
R W
RW
Niendorf
T
T
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D016477:Artifacts; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media / Q000008:administration & dosage; D004733:Enema; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis*; D007422:Intestines / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D008353:Mannitol; D012119:Respiration; D012680:Sensitivity and Specificity; D013996:Time and Motion Studies
D003287:Contrast Media; D008353:Mannitol