Characterization of focal liver lesions using quantitative techniques: comparison of apparent diffusion coefficient values and T2 relaxation times.
OBJECTIVE
To compare the efficacy of two quantitative methods for discrimination between benign and malignant focal liver lesions (FLLs): apparent diffusion coefficient (ADC) values and T2 relaxation times.


METHODS
Seventy-three patients with 215 confirmed FLLs (115 benign, 100 malignant) underwent 1.5-T MRI with respiratory-triggered single-shot SE DWI (b = 50, 400, 800) and dual-echo T2TSE (TR = 3,000 ms; TE1 = 84 ms; TE2 = 228 ms). ADC values and T2 relaxation times of FLLs were calculated. Sensitivity, specificity and accuracy of both techniques in diagnosing malignancy were assessed.


RESULTS
The mean ADC value of malignant tumours (1.07 × 10(-3) mm(2)/s) was significantly lower (P < 0.05) than that of benign lesions (1.86 × 10(-3) mm(2)/s ); however, with the use of the optimal cut-off value of 1.25 × 10(-3) mm(2)/s, 20 false positive (FP) and 20 false negative (FN) diagnoses of malignancy were noted, generating 79 % sensitivity, 82.6 % specificity and 80.9 % accuracy. The mean T2 relaxation time of malignant tumours (64.4 ms) was significantly lower (P < 0.05) than that of benign lesions (476.1 ms). At the threshold of 107 ms 22 FP and 1 FN diagnoses were noted; the sensitivity was 99 %, specificity 80.9 % and accuracy 89.3 %.


CONCLUSIONS
Quantitative analysis of T2 relaxation times yielded significantly higher sensitivity and accuracy in diagnosing malignant liver tumour than ADC values.


CONCLUSIONS
• Diffusion-weighted magnetic resonance imaging is increasingly used for liver lesions.                                                  • But ADC values demonstrated only moderate accuracy for differentiation of liver lesions.                                                  • T2 relaxation times yielded higher accuracy in diagnosing malignant liver tumours.                                                  • Both ADC and T2 values overlapped between focal nodular hyperplasia and malignant lesions.                                                  • Nevertheless T2 liver mapping could be valuable for evaluating focal liver lesions.
2nd Department of Clinical Radiology, Medical University of Warsaw, Ul. Banacha 1A, 02-097, Warsaw, Poland. andrzej.cieszanowski@wum.edu.pl
Andrzej
A
Cieszanowski
Agnieszka
A
Anysz-Grodzicka
Wojciech
W
Szeszkowski
Bartosz
B
Kaczynski
Edyta
E
Maj
Barbara
B
Gornicka
Mariusz
M
Grodzicki
Ireneusz P
IP
Grudzinski
Anna
A
Stadnik
Marek
M
Krawczyk
Olgierd
O
Rowinski
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005189:False Positive Reactions; D005260:Female; D006391:Hemangioma / Q000175:diagnosis*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008099:Liver / Q000473:pathology*; D008107:Liver Diseases / Q000175:diagnosis* / Q000473:pathology*; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity