Liver magnetic resonance imaging for evaluation of response to treatment after stereotactic body radiation therapy of hepatocellular carcinoma

Figure 1 Change in lesion diameter. MR: Magnetic resonance.

Figure 2 Tissue diameter with wash-in at pre-stereotactic body radiation therapy and follow-ups. MR: Magnetic resonance.

Figure 3 Variation in lesion diameters over time in basal, arterial, and hepatobiliary excretion phases.

Figure 4 Frequency of signal hyperintensity in T2-weighted and diffusion-weighted imaging sequences. MR: Magnetic resonance; DWI: Diffusion-weighted imaging.

Figure 5 Apparent diffusion coefficient value at pre-stereotactic body radiation therapy and follow-ups. MR: Magnetic resonance; ADC: Apparent diffusion coefficient.

Figure 6 Comparison of changes in T2-weighted and diffusion-weighted imaging findings and apparent diffusion coefficient values over time. ADC: Apparent diffusion coefficient; DWI: Diffusion-weighted imaging; T2W: T2-weighted; SBRT: Stereotactic body radiation therapy.

Figure 7 Frequency of perilesional parenchyma findings. MR: Magnetic resonance; HBP: Hepatobiliary phase.

Figure 8  Risk of presenting infield and outfield progression over time.

Figure 9  Infield and outfield progression and impact on survival.

Figure 10  Relationship between hepatobiliary phase hypointensity area and planning target volume. HBP: Hepatobiliary phase.

Figure 11  T2-weighted hyperintensity and diffusion-weighted imaging signal percentage at pre-stereotactic body radiation therapy and follow-ups. T2W: T2-weighted; DWI: Diffusion-weighted imaging.

Figure 12  Stereotactic body radiation therapy planning for hepatocellular carcinoma. A: Radiotherapy treatment planning with visualization of clinical target volume (pink line), planning target volume (red line), and areas of decreasing isodose; B: 3D rendering of the radiation beam and its incidence on the patient once positioned on the couch; C-E: Fusion Imaging of pre-stereotactic body radiation therapy planning (clinical target volume, pink line; planning target volume, red line; Isodose, 50% blue line) with magnetic resonance imaging images of the hepatobiliary excretion phase obtained 6 mo after the end of treatment. Band-like hypodensity during hepatobiliary excretion, an expression of functional resentment of the radio-treated parenchyma, is superimposed on the planning target volume area.

Figure 13  Hepatocellular carcinoma in a 75-year-old man treated with stereotactic body radiation therapy. A and B: Diffusion-weighted imaging signal of a lesion located in segment VII, before and after treatment. In the pre-therapy evaluation, the nodule presented a marked narrowing of the diffusion of water molecules, a feature no longer present at post-stereotactic body radiation therapy (SBRT) examination; C: Hepatocellular carcinoma nodule located in segment VII characterized by intermediate signal on T2-weighted imaging; D and E: Initial capsular retraction (white arrow) was already evident at the first post-SBRT magnetic resonance examination and particularly evident at the 9 mo follow-up; F and G: SBRT outcomes characterised by an area of "band" hypodensity in the hepatic excretion phase in the axial and coronal sequences, corresponding to shaded hyperintensity in the T2-weighted sequences with the same distribution and morphology; H: These findings are an expression of treatment-induced fibrosis as demonstrated by the histological finding, where postradiotherapy fibrotic tissue can be identified after liver transplantation.