Dynamic contrast-enhanced MRI in determining disease activity in perianal fistulizing Crohn disease: a pilot study.
OBJECTIVE
The objective of our study was to perform a semiquantitative analysis of dynamic contrast-enhanced MRI for the evaluation of disease activity and therapeutic response in patients with perianal fistulizing Crohn disease.


METHODS
Sixteen consecutively registered patients with perianal Crohn disease underwent pelvic MRI. A dynamic contrast-enhanced sequence was performed at 3 T (temporal resolution, 4.2 seconds) during i.v. contrast injection. Maximum enhancement, initial slope of increase, volume transfer constant (K(trans)), and the extravascular space fractional volume (x028B;(e)) were calculated in a region of interest drawn around the fistula. Perianal disease activity index, C-reactive protein concentration, and an MRI-based activity score were calculated as reference standards. Six patients underwent a second MRI examination 6 weeks after starting treatment with anti-tumor necrosis factor α (anti-TNF-α).


RESULTS
Perianal disease activity index moderately correlated with maximum enhancement (r = 0.67, p = 0.005), initial slope of increase (r = 0.58, p = 0.018), and volume of enhancing pixels (r = 0.79, p < 0.001) but not with K(trans) or x028B;(e). Volume of enhancing pixels also correlated with C-reactive protein concentration and the MRI-based score (r = 0.52, p = 0.041; r = 0.79, p < 0.001). The K(trans) values had decreased significantly 6 weeks after the start of anti-TNF-α therapy.


CONCLUSIONS
Maximum enhancement and initial slope of increase correlate with disease activity in perianal Crohn disease. K(trans) may be an indicator of the effect of therapy on patients starting anti-TNF-α treatment.
Department of Radiology, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. m.l.ziech@amc.uva.nl
Manon L W
ML
Ziech
Cristina
C
Lavini
Shandra
S
Bipat
Cyriel Y
CY
Ponsioen
Anje M
AM
Spijkerboer
Pieter C F
PC
Stokkers
Aart J
AJ
Nederveen
Jaap
J
Stoker
D000293:Adolescent; D000328:Adult; D002097:C-Reactive Protein / Q000032:analysis; D016009:Chi-Square Distribution; D003287:Contrast Media; D003424:Crohn Disease / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D012003:Rectal Fistula / Q000473:pathology*; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric
D003287:Contrast Media; D002097:C-Reactive Protein