Role of magnetic resonance imaging in intrathoracic hepatocarcinoma diagnosis

Abstract

WehavereadwithgreatinterestthearticlebyScanagattaand colleagues [1] reporting the case of a huge hepatocarci-noma (HCC) with intrathoracic extension. The authorsaddressed the diagnostic challenge to recognise tumourorigin and possible pitfalls with intrathoracic neoplasm; theyalso advocated the use of magnetic resonance imaging (MRI)to better characterise lesion relationships.Aswe candeduce from Fig. 1(c), itseemsa case ofHCC onnormal liver, which is infrequent and presents severaldiagnostic pitfalls. HCCs are hypervascular tumours anddemonstrate a strong arterial enhancement [2]; for thisreason, the finding of a single esofitic mass that extensivelyinfiltrates liver parenchyma with a strong arterial enhance-ment should be addressed in the first instance as HCC; inFig. 1(b) and (c), we can observe an arterial acquisition.Nevertheless, the tumour does not seem to present a strongarterial enhancement; this could be related to the extensiveintra-tumoral necrosis. However, we wonder if the authorshave used a bolus-tracking technique to obtain a correctarterial phase and also which acquisition delay has beenapplied?In Fig. 1(c), it also seems to appreciate a perihepaticeffusion without significant pleural effusion, which is aninfrequent finding for an extensive intrathoracic tumour.By our experience, we do not think that MRI couldbe useful to better define, in this case, tumour originand relationships. This is essentially because MRI has a lowerspatial resolution (3-mm slice thickness using volumetricsequences) compared with multidetector computed tomo-graphy (MDCT) (0.6-mm slice thickness) [3]. The realadvantages of MRI in characterisation of a liver lesion arerepresented by its intrinsic contrast, which offers thepossibility to characterise the different components ofthe lesion (haemorrhage, fat and iron) [4] and also by thepossibility to administrate hepatobiliary-specific mediumcontrast, which permits to distinguish lesions from function-ing hepatocytes or Kupffer cells [5].We conclude that, in this case, MDCTrepresents the besttechnique in the attempt to characterise the lesion and itsspatial relationships, and to permit a complete oncologicalstaging with whole body examination.