'Curved tunnel' sign on MRI: a typical radiological feature in hepatic trichinellosis

To summarize the clinical and radiological features of hepatic trichinellosis.

Patients diagnosed with trichinellosis and liver involvement in our institution since 2011 were included retrospectively. Then, qualified patients were divided into a seropositive group and a clinically diagnosed group. Preoperative liver CT and/or MRI images were evaluated independently by two radiologists. The correlations between the radiological and pathological features were evaluated by a radiologist and a pathologist. Independent t-tests were carried out to assess clinical data between groups and those reported in the previous literature. Values of P less than 0.05 were considered statistically significant.

Eventually, ten patients were enrolled, five in each group. All patients recovered successfully after surgical (n = 8) or conservative treatment (n = 2). The clinical, radiological, and pathological features were highly consistent between the two groups. All patients were under 60 years of age (48.0 ± 7.9 years in the seropositive group, 48.6 ± 10.1 years in the clinically diagnosed group), and they were older than those previously reported in the literature (30.5 ± 17 years, n  =  31; P = 0.032 and 0.028). Eosinophilia was found in four patients, and all were mildly increased (˂ 1.5 × 10⁹/L). Lesions in all patients were in the right lobe of the liver, and nine of them showed a characteristic 'curved tunnel' sign on DCE-MRI images. None of the patients had signs or evidence of extrahepatic infection.

The 'curved tunnel' sign on MRI is a typical radiological feature in hepatic trichinellosis.