·       Brain MRI protocol :

      To assess FD’s neurological involvement, our brain MRI routine protocol includes : 

- 3D T1 weighted,  

- axial FLAIR weighted,

- axial Diffusion Weighted Image (DWI),

- coronal T2 weighted,

- Time Of Flight (TOF-MRA) sequence,

- 3D Susceptibility Weighted Image (SWI).

- ventricular volume measurement with Fast Imaging Employing Steady-state Acquisition Cycled Phases sequence (FIESTA).

- in some cases, 3DT1 contrast enhancement and DTI is performed.

·       Findings :

        Ø  Cerebrovascular involvement :

     You have to look for cerebral infarction (lacunar, ischemic or hemorrhagic) and microbleeds presence (Fig. 2, Fig. 3, Fig. 4).

      It can touch 25-30% of the patient with a FD. The localization is posterior depending of the vertebro-basilar system. A diagnosis of Fabry's disease should always be considered in young patients who have had a stroke. Indeed, in a study, the prevalence of strokes in FD was estimated to be 6.9% in males and 4.3% in females, much higher than in the general population. Median age at first stroke was 39 in men and 46 years in women and stroke may be the first manifestation of the disease. A recidive at 6 years was noted in more 50% of the patients [3].

      A specific sign is the dilatation of intracranial vessels, mainly a dolichoectasia of the vertebro-basilar vessels (Fig. 5).  A study showed the progressive and profound vessel remodeling that ultimately leads to basilar artery dolichoectasia with increased basilar artery diameter, length, and tortuosity. This 3 parameters could be an interesting tool for monitoring the disease and the possible response to treatments [4]. To improve the reproducibility, the measurement needed to be perform using the multiplanar reconstruction on the TOF-MRA sequence.

        Ø  White-matter lesions (WML) :

        There could be white-matter lesions to characterize and quantify [5].

We use the Fazekas classification : for each localization (periventricular, deep, subcortical white matter, it is a qualitative quantification from no anomaly (Fasekas 0), small punctate lesions (Fasekas 1) (Fig. 7), larger WML that are beginning to become confluent (Fasekas 2) (Fig. 8), to extensive confluent WML (Fasekas 3) (Fig. 9).

       We also classify the topography of the white matter alteration between a carotid predominance, a vertebro-basilar predominance or a well-balanced involvement (Fig. 6).

       A quantitative approach is now possible with DWI sequence. In fact, it has been shown  that raised ADC values could predate conventional MRI changes in Fabry disease and therefore be a more sensitive marker of disease progression and response to enzymatic replacement therapy [6].

      Moreover, new brain structural MRI methods such as DTI could provide a pattern of ultrastructural changes without visible WML. DTI measurements could also provide parameters to monitor the structural brain involvement and the potential effects of  a treatment [7].

        Ø  Grey-matter involvement :

       The T1 hyperintensity in pulvinar thalami is a highly specific sign (Fig. 10) [8]. It is more frequent in male patients with cardiomyopathy and severe kidney involvement [1].

      This finding was assumed to be caused by calcification as a consequence of disturbed local circulation (Fig. 11) [9].

       Other calcium deposits can be find thanks to SWI in globus pallidi (Fig. 12) or dentate nuclei. Thanks to this sequence, it is also possible to make the difference between calcifications or microbleeds (Fig. 13).

        Ø  Cranio-cervical junction involvement :

      In a pilot study with a cohort of 44 patients, a Chiari type 1 malformation was identified in 6 patients (Fig. 14) [10].

        Ø  Meningeal involvement :

      Rare cases of aseptic meningitis were described with, for example, leptomeningeal contrast enhancement [2].

        Ø  Ventricular 3D volume :

        Dilatation can be observed in patients with compressive dolichoectasia of vertebra-basilar vessels (Fig. 15).

        Furthermore, recent studies are interested in the hippocampal volume [11], the cerebral blood flow, or the changes of DTI and FBFI (fast bound-pool fraction imaging) in the white matter [7].