Colorectal hepatic metastases: detection with SPIO-enhanced breath-hold MR imaging--comparison of optimized sequences.
OBJECTIVE
To compare the accuracy of four breath-hold magnetic resonance (MR) imaging sequences to establish the most effective superparamagnetic iron oxide (SPIO)-enhanced sequence for detection of colorectal hepatic metastases.


METHODS
Thirty-one patients with colorectal hepatic metastases underwent T1-weighted gradient-echo (GRE) and T2-weighted fast spin-echo (FSE) MR imaging before and after SPIO enhancement. Four sequences were optimized for lesion detection: T2-weighted FSE, multiecho data image combination (MEDIC), T2-weighted GRE with an 11-msec echo time (TE), and T2-weighted GRE with a 15-msec TE. Images were reviewed independently by three blinded observers. The accuracy of each sequence was measured by using alternative free-response receiver operating characteristic analysis. All results were correlated with findings at surgery, intraoperative ultrasonography, or histopathologic examination. Differences between the mean results of the three observers were measured by using the Student t test.


RESULTS
Postcontrast T2-weighted GRE sequences were the most accurate and were significantly superior to postcontrast T2-weighted FSE and unenhanced sequences alone (P <.05). For all lesions that were malignant or smaller than 1 cm, respectively, mean accuracies of postcontrast sequences were 0.082 and 0.64 for T2-weighted FSE, 0.90 and 0.78 for MEDIC, 0.92 and 0.80 for GRE with an 11-msec TE, 0.93 and 0.82 for GRE with a 15-msec TE, and 0.81 and 0.62 for unenhanced sequences.


CONCLUSIONS
Optimized SPIO-enhanced T2-weighted GRE combined with unenhanced T2-weighted FSE MR sequences were the most sensitive. Breath-hold FSE postcontrast sequences offer no improvement in sensitivity compared with unenhanced sequences alone.
Ward
Janice
J
Department of Clinical Radiology, St James's University Hospital, Beckett St, Leeds LS9 7TF, England. janice.ward@leedsth.nhs.uk
Guthrie
J Ashley
JA
Wilson
Daniel
D
Arnold
Paul
P
Lodge
J Peter
JP
Toogood
Giles J
GJ
Wyatt
Judith I
JI
Robinson
Philip J
PJ
D015179:Colorectal Neoplasms / Q000473:pathology*; D003287:Contrast Media; D005188:False Negative Reactions; D005189:False Positive Reactions; D005290:Ferric Compounds; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology / Q000556:secondary* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015588:Observer Variation; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
D003287:Contrast Media; D005290:Ferric Compounds; C000499:ferric oxide