Quantitative assessment of iron-oxide-enhanced magnetic resonance imaging of the liver: Vessel isointensity is a potential characteristic of liver hemangiomas on late T1-weighted images.
OBJECTIVE
To test whether a new quantitative measure, the tumor-to-vessel ratio, obtained from late post-iron-oxide-enhanced T1-weighted images allows for differentiating hemangiomas from liver metastases or all malignant liver lesions.


METHODS
Twenty-six patients (mean 57, range 33-79 years) were prospectively studied at 1.5T magnetic resonance imaging (MRI) with a T1-weighted 2D fast low-angle shot (FLASH) sequence (repetition time/echo time/flip angle; 200 ms/4.8 ms/90 degrees ) and a T2-weighted turbo spin-echo sequence (4072 ms/99 ms/180 degrees ). Imaging was carried out before and at intervals up to 18 min after IV injection of Ferucarbotran (Resovist, Schering, Germany). In 19 patients, one representative malignant lesion was analysed. Eleven hemangiomas were evaluated in 7 patients. Two readers performed a consensus reading with a signal intensity measurement in a lesion, normal liver and hepatic veins, from which ratios were computed.


RESULTS
On T1-weighted iron-oxide-enhanced MRI of 30 lesions, tumor-to-vessel signal intensity ratios were distinct in hemangiomas (median 1.04, range 0.99-1.10) as opposed to either metastases (0.64, 0.33-0.77; P < 0.05) or all malignant lesions taken together (0.64, 0.33-0.98; P < 0.05), while the tumor-to-liver ratio was not.


CONCLUSIONS
The tumor-to-vessel ratio may help to differentiate between hemangiomas and metastases. A ratio greater than 0.98 allowed differentiating hemangiomas from metastases with a wide safety margin.
Schmitz
S A
SA
Klinik und Hochschulambulanz für Radiologie und Nuklearmedizin, Campus Benjamin Franklin, Charité Berlin, Germany. Stephan.Schmitz@imperial.ac.uk
Nikolova
A
A
O'Regan
D
D
Albrecht
T
T
Hohmann
J
J
Wolf
K-J
KJ
D000328:Adult; D000368:Aged; D003287:Contrast Media; D003911:Dextrans; D003937:Diagnosis, Differential; D005260:Female; D052203:Ferrosoferric Oxide; D019786:Gadolinium DTPA; D006391:Hemangioma / Q000175:diagnosis*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007501:Iron; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D008297:Male; D008875:Middle Aged; D010087:Oxides; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography / Q000379:methods
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007501:Iron; C065507:ferumoxides; D019786:Gadolinium DTPA; D052203:Ferrosoferric Oxide