Tag: MRI biomarkers

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DTI-MRI biomarkers in the search for normal pressure hydrocephalus aetiology

DTI chronic hydro

Neurosurg Rev (2015) 38:239–244

Normal pressure hydrocephalus (NPH) is a clinical syndrome characterized by gait disturbances, urinary incontinence and dementia. Clinical presentation overlaps with Alzheimer disease (AD).Early recognition thus early intervention (shunting) is important for successful treatment, but lack of a diagnostic test with sufficient sensitivity and specificity complicates the diagnosis.

We performed literature search and composed a structured review of imaging biomarkers of NPH. Morphometric studies are not sufficient to diagnose NPH. Hydrocephalus is a common finding in elderly people due to the symmetric brain atrophy and is even more pronounced in patients with AD. The key MRI biomarker seems to be diffusion tensor imaging (DTI). According to recent studies, the DTI analysis of the splenium corporis callosi, posterior limb of internal capsule, hippocampus and fornix combined with measurement of Evans index is a promising MRI biomarker of NPH and could be used for NPH diagnostics and in the differential diagnosis from AD and other dementias.

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Recurrent high-grade glioma treated with bevacizumab: prognostic value of MGMT methylation, EGFR status and pretreatment MRI in determining response and survival

Recurrent GBM and bevacizumab

J Neurooncol (2013) 115:267–276

Although bevacizumab represented an important advance in treatment of recurrent high-grade gliomas (HGG), responses occur in fewer than half of patients. There are no validated biomarkers for anti-angiogenic therapy that are available for routine clinical use.

We assessed the prognostic values of imaging and molecular markers in this patient population. MRI scans from 191 patients with recurrent HGG obtained prior to initiating bevacizumab were reviewed for areas of enhancement, necrosis, T2/FLAIR abnormality, and ADC values. Serial MRI scans following the initiation of bevacizumab were evaluated for response and progression. Non-radiographic markers including EGFR and MGMT status were also assessed with respect to response and patient survival.

65 of 191 patients (34 %) showed complete or partial response at the time of their best response MRI and demonstrated longer progression free survival (PFS) and overall survival (OS) compared to the group without response (PFS: 6.9 vs 3.5 months, OS: 10.9 vs 6.1 months). Minimum ADC values within enhancing and non-enhancing regions were lower in responders compared to those of nonresponders (1,099 vs 984 x 10-6 mm2/s, p = 0.006). Smaller enhancing area was associated with longer OS (HR = 1.99, p = 0.017). The ratio of T2/FLAIR to enhancing area was prognostic of OS for only the Grade III HGG subgroup (HR = 0.14, p = 0.004).

Area of enhancing tumor at baseline can stratify survival in patients with recurrent HGG treated with bevacizumab. The extent of edema relative to enhancing area may have a prognostic role specific to Grade III HGG.

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