State of the art in magnetic resonance imaging of hepatocellular carcinoma
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26 nov 2018
INFORMAZIONI SU QUESTO ARTICOLO
Categoria dell'articolo: Review
Pubblicato online: 26 nov 2018
Pagine: 353 - 364
Ricevuto: 02 ott 2018
Accettato: 19 ott 2018
DOI: https://doi.org/10.2478/raon-2018-0044
Parole chiave
© 2018 Natally Horvat, Serena Monti, Brunna Clemente Oliveira, Camila Carlos Tavares Rocha, Romina Grazia Giancipoli, Lorenzo Mannelli, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.
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Main indications of MRI for hepatocellular carcinoma (HCC)
| Main indications of MRI for HCC evaluation |
|---|
| Nodules larger than 1.0 cm identified on ultrasound |
| For patients on the orthotopic liver transplantation waiting list |
| When the imaging features of the nodule on CT are not elucidative |
| History of allergy to iodinated contrast agent used on CT scans |
| After locoregional therapy |
MRI and CT estimated sensitivity for the detection of hepatocellular carcinoma (HCC)
| MRI | CT | CEUS | |
|---|---|---|---|
| 82% | 77% | 73% | |
| 96% | 94% | 94% | |
| 66% | 63% | 77% |
Main imaging features of hepatocellular carcinoma (HCC)
| Imaging features | Description |
|---|---|
| Increased enhancement in the arterial phase. Reflects tumor neoangiogenesis. | |
| Hypoenhancement of the lesion compared with background liver tissue. Secondary to HCC extracellular reduced volume, rapid venous drainage and reduced intranodular portal venous supply. | |
| Observed in approximately 80% of HCCs, detected on delayed phase, secondary to the lack of portal supply to malignant nodules. Corresponds to a pseudocapsule consisting of compressed adjacent liver parenchyma with occasional nonspecific inflammatory cells on histology. | |
| HCC invades and grows within the lumen. The vein appears dilated and with the same pattern of enhancement observed in the nodule. | |
| The elevated signal intensity on T2WI can be useful to differentiate HCC from dysplastic nodules. | |
| Mildly elevated signal relative to the surrounding liver parenchyma on diffusion weighted imaging (DWI) and low signal intensity on apparent diffusion coefficients (ADC) map. | |
| Enhancement of the peritumoral parenchyma after enhancement of the tumor itself, because of the passage of contrast through the draining sinusoids and portal venules into the surrounding sinusoids. | |
| Loss of signal on the opposed-phase T1WI compared with the in-phase images. | |
| Siderotic nodule is likely to be a dysplastic nodule. Development of an iron-free around the nodule suggests HCC foci. | |
| Nodular areas interspersed by areas of fibrosis, hemorrhage, arteriovenous shunting and necrosis. Characteristic of progressed HCCs. | |
| Mildly elevated signal intensity on T2WI within nodule with low signal intensity, representing the focus of HCC within the low density dysplastic nodule, that may also enhance in the arterial phase. | |
| Hypointensity compared with background liver following administration of a hepatobiliary contrast agent (2–5 minutes after contrast media administration). | |
| Hypointensity compared with background liver following administration of a hepatobiliary contrast agent (20 minutes after). |
Main classifications used to assess tumor response after locoregional treatment
| Criteria | System | Response | Definition |
|---|---|---|---|
| Disappearance of all TL | |||
| ≥ 50% decrease in CP of TL | |||
| < 50% decrease to ≤25% increase in CP of TL | |||
| > 25% increase from maximum response of TL | |||
| Disappearance of all TL | |||
| ≥ 30% decrease in MD of TL | |||
| < 30% decrease to ≤20% increase in MD of TL | |||
| > 20% increase from maximum response of TL | |||
| Disappearance of any intratumoral enhancement in all TL | |||
| ≥ 30% decrease in SMD of enhancing tissue in TL | |||
| < 30% decrease to ≤20% in SMD of enhancing tissue in TL | |||
| > 20% increase in amount of enhancing tissue in TL | |||
| Disappearance of any intratumoral enhancement in all TL | |||
| ≥ 50% decrease in amount of enhancing tissue in TL | |||
| < 50% decrease in amount of enhancing tissue in TL | |||
| > 25% increase in amount of enhancing tissue in TL and/or new enhancement in previously treated lesions | |||
| No suspicious lesion enhancement | |||
| Atypical enhancement not meeting criteria to viable tumor | |||
| Nodular, mass-like, or thick irregular tissue in or along the treated lesion with any of the following: arterial phase hyperenhancement or washout appearance or enhanced similar to pretreatment 100% of tumor necrosis or reduction | |||
| Necrotized area larger than the tumor (enough ablative margin) | |||
| Necrotized area similar in size to the tumor (insufficient ablative margin) | |||
| 50–100% of tumor necrosis or reduction | |||
| Other effect than TE3 and TE1 | |||
| Tumor enlargement of > 25% regardless of necrosis |
MRI sequences and hepatocellular carcinoma (HCC) features that can be assessed in each sequence
| MRI sequences | HCC imaging features |
|---|---|
| Usually hyperintense | |
| Intralesional microscopic fat (lower signal on opposed-phase) or iron (lower signal on in-phase) | |
| Demonstrates the presence of macroscopic fat and blood products After locoregional therapies, hyperintensity indicates coagulative necrosis | |
| Hyperenhancement | |
| Washout and capsule appearance | |
| Washout and capsule appearance | |
| Restricted diffusion (helps to identify small lesions) | |
| Characterizes contrast enhancement in spontaneously hyperintense nodules on T1WI pre-contrast (especially important for lesions with blood products and after locoregional treatment) | |
| Helps to differentiate HCC from mass-like lesions or extra-hepatic lesions | |
| Generally hypointense |