Other Tumour Types

Susceptibility contrast MRI has also been reported to have some clinical benefit in a number of other tumour types. Comparisons of rCBV values between

Fig. 9.4a,b. a The histograms on the top left and lower left illustrate the frequency of particular values of rR in a low-grade (top) and high-grade (bottom) glioma. Note that the low-grade glioma shows close conformity to a normal distribution whereas the high-grade glioma shows a marked skewness of the distribution with a tail to the right. This pattern can be explained by the image on the right side (b) which shows a grey scale map of rCBV in a high-grade glioma overlaid with red areas which indicate significant elevation of rR. Only a small number of the total tumour pixels exhibit abnormally high values. Because of this mean values from large regions of interest are not significantly different between different tumour types; however, the shape of the distribution is affected

Fig. 9.4a,b. a The histograms on the top left and lower left illustrate the frequency of particular values of rR in a low-grade (top) and high-grade (bottom) glioma. Note that the low-grade glioma shows close conformity to a normal distribution whereas the high-grade glioma shows a marked skewness of the distribution with a tail to the right. This pattern can be explained by the image on the right side (b) which shows a grey scale map of rCBV in a high-grade glioma overlaid with red areas which indicate significant elevation of rR. Only a small number of the total tumour pixels exhibit abnormally high values. Because of this mean values from large regions of interest are not significantly different between different tumour types; however, the shape of the distribution is affected common extra-axial tumours and typical enhancing inter-axial tumours shows the extra-axial masses to typically have higher values. This may be helpful in differentiating between intra and extra-axial masses where other features are equivocal (Sugahara et al. 1999a). Measurements of rCBV can also help to differentiate between meningiomas, schwannomas and neurinomas, meningiomas having higher values of rCBV than those seen in neurinomas or schwannomas (Maeda et al. 1994; Miyati et al. 1997; Sugahara et al. 1999b; Uematsu et al. 2000). rCBV can also provide supplementary information to differentiate between malignant lymphoma and glioma because the absence of tumour neovascularization of malignant lymphoma leads to low rCBV, in contrast to malignant gliomas (Sugahara et al. 1999b). Cha et al. (2002) in their series of 19 consecutive patients (Cha et al. 2002) with primary cerebral lymphoma found the maximum rCBV ranged from 0.42 to 3.41 (mean, 1.44±0.67) compared to mean rCBV of 5.5±4.5 in 51 patient with glioblastoma multiforme (p<0.01) (Frazzini et al. 1999). Cha et al. (2002) have also identified DSCE-MRI as a useful diagnostic tool in differentiating tumefactive demyelinating lesions (TDL) from intracranial neoplasms. The rCBV values of TDLs ranged from 0.22 to 1.79 (n=12), with a mean of 0.88±0.46 (SD) compared to rCBV values of 1.55-

19.20 (n= 11), with a mean of 6.47±6.52 in intracranial neoplasms (p=0.009).

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