[Differential diagnosis of liver focal formations at diffusion MRI].

PURPOSE: To define the role of diffusion-weighted imaging and MRI contrast enchanced in the differential diagnostics of focal liver lesions.

METHODS AND MATERIALS: Forty patients with focal liver lesions (23 metastases, 32 cysts, 24 hemangiomas) underwent MRI at 1.5 T scanner. The protocol included T1, T2-imaging, DWI. For DWI we used b = 50, 400 s/mm2. Coefficient of signal intensity (kSI) for different sequences was counted by the formula: kSI = (SIa-SIb)/(SIa + SIb), where SIa was the lesion signal intensity, SIb was SI of normal liver parenchyma.

RESULTS: Metastases had maximal kSI of DWI with b = 400 (kSI = 0.44 U) and minimal signal intensity of T1-WI (kSI = 0,29 U). On T1-W images the cysts differed greatly from liver parenchyma and from other focal lesions (kSI = 0,37 U), but hemangiomas hardly differed from metastases on this sequence (kSI, for these lesions was equal, 0.14 U). Using DWI made the differential diagnosis of different liver lesions easier because their kSI were significantly different: kSI for cysts was 0.68 U, kSI of hemangiomas was 0.61 U, kSI of metastases was 0,30 U. We need more studies for define the role of MRI contrast enchanced in the differential diagnostics of focal liver lesions.

CONCLUSION: DWI plays an important role in differential diagnostics of focal liver lesions and should be included in protocol of examination of patients with liver pathology.