Imaging of small hepatic metastases of colorectal carcinoma: how to use superparamagnetic iron oxide-enhanced magnetic resonance imaging in the multidetector-row computed tomography age?
OBJECTIVE
To compare the accuracy of dynamic contrast-enhanced multidetector-row computed tomography (CT) and superparamagnetic iron oxide-enhanced magnetic resonance imaging (MRI) in the evaluation of small hepatic metastases of colorectal carcinoma.


METHODS
Of 94 patients with colorectal carcinoma analyzed, 76 hepatic metastases (<2 cm) were diagnosed in 17 patients. Superparamagnetic iron oxide (SPIO)-magnetic resonance (precontrast and postcontrast MRI) and dynamic contrast-enhanced multidetector-row CT (dynamic CT [precontrast, arterial, portal-venous, and delayed phase]) were evaluated. The alternative free-response receiver operating characteristic analysis was performed, and the sensitivities and positive predictive values were analyzed.


RESULTS
The Az values and sensitivities of portal-venous phase CT, dynamic CT, and SPIO-MRI (0.62/59%, 0.69/61%, and 0.67/61%) were identical. The mean positive predictive value of dynamic CT (82%) was inferior to that of SPIO-MRI (91%).


CONCLUSIONS
The diagnostic ability of dynamic CT is identical to that of SPIO-MRI in Az value and sensitivity. Superparamagnetic iron oxide-MRI should be recommended only if an equivocal lesion is detected by dynamic CT.
Department of Radiology, University of Yamanashi, Chuo-shi, Yamanashi-ken, Japan. utaroh-motosugi@nifty.com
Utaroh
U
Motosugi
Tomoaki
T
Ichikawa
Hiroto
H
Nakajima
Hironobu
H
Sou
Mika
M
Sano
Katsuhiro
K
Sano
Tsutomu
T
Araki
Hiroshi
H
Iino
Hideki
H
Fujii
Tadao
T
Nakazawa
D000368:Aged; D015179:Colorectal Neoplasms / Q000473:pathology; D003287:Contrast Media; D003911:Dextrans; D005188:False Negative Reactions; D005260:Female; D052203:Ferrosoferric Oxide; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007472:Iohexol; D007501:Iron; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D008875:Middle Aged; D010087:Oxides; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007472:Iohexol; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide