The objective of this educational paper is to describe the most common focal and diffuse hepatic lesions with a characteristic hyperintense signal on T1-weighted images and to provide a differential diagnosis among them.
Signal intensity of T1 weighted images is due to several factors such as the chemical composition of tissues,
scanning sequences parameters and use of contrast medium .
T1 tissue relaxation time is the main factor that sets signal intensity in Magnetic Resonance Imaging (MRI) .
Normal liver tissue has a short T1 relaxation time : for this reason,
only lesions that contain T1-shortening elements appear relatively hyperintense.
Below are the most common causes of T1 hyperintensity:
-Due to its short T1 relaxation time,
Findings and procedure details
According to their histopathology liver lesions can be distinguished in benign and malignant.
Benign liver lesions
Diffuse hepatic steatosis (Fig. 1): due to overload of triglycerides within the hepatocytes; may be distinguished an alcoholic- and nonalcoholic-disease.
Since it is a benign lesion,
there are no mass effect/infiltration of liver vessels and no contrast-enhanced areas of inhomogeneities.
Out-of-phase T1w-images show loss of signal.
Wilson’s disease: an autosomal recessive disease that is characterized by increased intestinal copper uptake due to abnormal caeruloplasmin metabolism and subsequent...
MRI is a reliable diagnostic tool in recognizing focal and diffuse T1 hyperintense liver lesions and providing a characterization through their specific influence of T1 relaxation time.
Knowledge of the T1 signal characteristics of substances such as fat and hemoglobin degradation products allow the radiologist to perform a correct diagnosis.
1 Richard Bitar et al. MR Pulse sequences: what Every Radiologist Wants to Know but Is Afraid to Ask RadioGraphics 2006; 26:513–537- Published online 10.1148/rg.2620550632
2 De Bazelaire CM,
MR imaging relaxation times of abdominal and pelvic tissues measured in vivo at 3.0 T: Preliminary results.
Radiology 2004; 230:652-659
3 Prasad SR,
et al: Fat-containing lesions of the liver.
Radiographics 2005; 25:321-331
4 Srinivasa R.
Humberto Rosas et al.