HEPATIC HEMANGIOMA

Q.All are true regarding MRI of hepatic hemangioma except

a.MRI ---the most sensitive modality for detection

b.T1 and T2 relaxation times considerably shorter  than that of solid hepatc tumour or normal heapatic parenchyma

c.hypointense on T1 image and significantly hyperintense on T2 image

d.light bulb sign on T2

e.show greater hypointensity on T1 and proton-weighted image compared to cyst

ANS.---b

T1 and T2 relaxation times of hemangioma are considerably longer  than that of solid hepatc tumour or normal heapatic parenchyma.So,hemangioma appear hypointense on T1 images and significantly hyperintense on T2images.Unlike most primary or metastatic liver lesions ,which generally have shorter T2relaxation times ,hemangioma typically retain their marked signal intensity on heavily T2-Weighted multiecho (echo delay times in excess of 100msec) accounting for the so called “light bulb” sign .The signal intensity of hemangioma resembles that of CSF ,which may be used as an internal reference standard on such images.Although simple hepatic cyst may demonstrate a similar hyperintensity on T2 images ,they can usually be distinguished by their relative greater hypointensity on both T1 and proton density

Hemangioma typically exhibit a homogenous hyperintense pattern ,whereas metastases commonly display a heterogenous amorphous appearance .Ringed morphology,indistinct margination ,or surrounding peritumoral edema. The light-bulb sign is not 100% specific for hemangioma ,as anywhere from 9% to 27% of hepatic metastases also demonstrate a homogeneous hyperintense pattern on T2 images.