[Steatohepatitis--a challenge?]

With the increasing use of cross-sectional imaging techniques both diffuse and focal fat accumulations in the liver are frequent incidental findings. Focal fatty changes in particular, such as localized distribution disorders in steatohepatitis or focal fat deposition of the liver, can lead to difficulties in the correct diagnosis of patients with a history of malignant disease.

Ultrasound is used as the first imaging modality in most cases but has a relatively low sensitivity and specificity. In most cases a further diagnosis of diffuse fatty liver accumulations is possible with non-contrast computed tomography (CT) scanning and chemical shift imaging in magnetic resonance imaging (MRI) enabling an even further differential diagnostic distinction of fatty disorders of the liver.

For the detection of generalized fatty liver disease ultrasound has a sensitivity and specificity of 60-100% and 77-95%, respectively. Non-contrast CT of the liver attains a sensitivity of between 43% and 95% with a specificity of 90%. Sensitivity and specificity for chemical shift imaging of MRI are 81% and 100%, respectively.

For advanced differential diagnostic distinction of the different forms of fatty liver disorders and for the correct diagnosis of benign and malignant liver lesions the leading imaging modality is chemical shift imaging of MRI (in-phase and opposed-phase).