| セッション情報 |
International Forum 2(Liver) 2.Pathology
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| タイトル |
IF2-2-III (Keynote lecture) Multistep hepatocarcinogenesis: Correlation of imaging with pathology
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| 演者 |
Masatoshi Kudo（Kinki University School of MedicineOsaka-sayamaJapan） |
| 共同演者 |
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| 抄録 |
The method for early detection of hepatocellular carcinoma （HCC） has been well established in JapanThere has been another important issue of accurate characterization of nodular lesions found in cirrhoticliver． This problem has been solved by the development of imaging modalities such as contrast-enhancedUS （CEUS）computed tomography during hepatic arteriography （CTHA） and computed tomographyduring arterial portography （CTAP）． lt is most important to differentiate the typical hemodynamic pat-terns of a low-grade dysplastic nodule （LGDN） having arterial hypovascularity with portal perfusion pre-served from those of HCC characterized by arterial hypervacularity with decreased portal perfusion．The most sensitive modality capable of objectively depicting the early carcinogenesis process among cur-rently available imaging systems is （1） CTAPfollowed by ： （2） CTHA（3） contrast-enhanced ultra-sonography （US）and （4） SPIO-MRI． Portal blood fiow may be maintained in some cases of DN and earlyHCCbut reduced in other noduleseven though the pathology remains as early HCCin which arterialblood flow has not yet increased． CTAP may sharply detect the earliest initial change of HCC． The secondearliest initial carcinogenic change is detected as an increase in intranodular arterial blood flow by CTHAor contrast-enhanced US． Hypervascular lesions depicted as nodule-in-nodule or as entire hypervascularcan be interpreted as advanced cancereven though they are smallwhich might have already reached amore advanced stage than early liver cancer．There are variations among cases regarding whether SPIO-MRI or CTHA detects the initial malignantor cancerous changes earlier． Some hypervascular well-differentiated liver cancer nodules may uptakeSPIO on MRIbut uptake reduction has already started in some hypovascular tumor nodules． Thereforethe generalization of findings occurring earlier in carcinogenesis remains difficulti.e.sinusoidal capillari-zation and the number of Kupffer cells （function） are somewhat dissociated in some cases．When Sonazoid is used for CEUSthe combination with MDCT increases the accuracy of detecting intra-nodular arterial vascularitycompared to that by a single method． Addition of the post-vascular phase（Kupffer phase） allows an assumption of the degree of malignancy based on Kupffer function． Based onthe abovewhen uptake is reduced in the Kupffer phase of SPIO-MRI or Sonazoid CEUS in nodules notdepicted as hypervascular lesions by MDCT or dynamic MRIthe nodules should basically be treated anda biopsy is not essential．When uptake is noted on SPIO-MRIbiopsy should be performed if at all possibleand when diagnosed astypical well-differentiated HCCthe lesion should be treated． When SPIO-MRI detects uptakeand CTHAor CTAP detects a malignant findingi.e.increased arterial blood flow or reduced portal blood flowthe le-sion should be regarded as maligriant． Howeverwhen hypovascular arterial blood flow is noted while theportal blood flow is isovasculara biopsy is necessary． Nodules histologically diagnosed as benign lesionsby biopsy may be subjected to observation without any treatmentbut those histologically diagnosed astypical well-differentiated HCC by biopsy should be treated as early HCC．In conclusionimaging findings including CEUSSPIO-MRICTHAand CTAP correlate well with patho-logical diagnosis in the most of LGDN and typical HCChoweverit is sometimes difficult to distinguishHGDN from early HCC or well-differentiated HCC． |
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