Figure 1
Figure 1
Axial T2W image shows bilateral symmetrical increased T2 signal intensities in the parieto-occipital lobes, splenium, and optic radiation tracts.
Adrenoleukodystrophy
SectionPaediatric radiology
Case TypeClinical Cases
AuthorsRasalkar DD, Chu CWW, Hui J, Paunipagar BK
Connected authors
10 years, male
Clinical History
A 10-year-old boy presented with progressive visual disturbances since age of 2.
Imaging Findings
A 10-year-old boy presented with progressive visual disturbances since age of 2. On examination he had raised blood pressure. There was no neurological deficit. Cranial MRI showed symmetrical T2 hyperintensities in the posterior periventricular white matter, splenium and optic radiations track (Fig. 1 and 2). Post contrast scan revealed a peripheral enhancement (Fig. 3). There was high choline and corresponding decrease in N-acetylaspartate (NAA) peak on MR spectroscopy (Fig. 4).A multi-directional diffusion tensor imaging (DTI) showed reduced white matter fibres with reduced fractional anisotropy (FA) in the splenium of corpus callosum and optic radiations [right-(FA=0.237 +/- 0.079) and left (FA=0.247 +/- 0.093)] with corresponding increased apparent diffusion coefficient (ADC)[(right-(FA=1.295 +/- 0.335) and left (FA=1.335 +/- 0.403)] (figure 5). MRI findings were highly suggestive of cerebral adrenoleukodystrophy when correlated with the clinical status of the young boy. There was no family history of ALD so far.
Discussion
X-linked adrenoleukodystrophy (ALD) is a genetic disorder affecting the central nervous system, adrenal cortex, and testes [1]. Cerebral ALD is characterised by cerebral white matter demyelination. The affected brain white matter is usually divided into three pathological zones in cerebral ALD. A central zone consists of gliosis and scattered astrocytes with absence of oligodendroglia, axons, myelin, and inflammatory cells. A more peripheral zone shows numerous perivascular inflammatory cells, demyelination with preservation of axons. An outermost zone is made up of active destruction of the myelin sheath and lack of perivascular inflammatory cells. In advanced stages, these zones are generally depicted on routine MR imaging.
Bone marrow transplantation has a favourable effect early in the disease. The preliminary agreement is to limit BMT to the patients with a Loes score < 4, based on conventional imaging, which might underestimate the severity of the neurologic injury and delay the therapeutic decisions [2].
Diffusion tensor imaging (DTI) is a noninvasive method for evaluating diffusivity and directionality of free water molecules. The loss of fractional anisotropy (FA) suggests disintegration of myelin sheath and axons, while increase in apparent diffusion coeficient (ADC) suggests injury to the structures that restrict water diffusion which appear quite earlier and missed by conventional imaging. The FA value in the affected area is significantly lower while the ADC one is higher compared to the apparently unaffected area. Thus, DTI and FA plus ADC calculations are helpful noninvasive clinical techniques that may improve the evaluation of patients with ALD and thereby helping in earlier management [3].
MR spectroscopy reveals decrease in NAA and raised choline compatible with neuronal/axonal loss and enhanced myelin turnover related to demyelination respectively. These findings have been reported in white matter that have a normal appearance on both conventional MR and DT images[4]. MR spectroscopy, therefore has been suggested as most sensitive technique for detecting early abnormalities of demyelination or axonal loss in patients with X-ALD[4].
Bone marrow transplantation has a favourable effect early in the disease. The preliminary agreement is to limit BMT to the patients with a Loes score < 4, based on conventional imaging, which might underestimate the severity of the neurologic injury and delay the therapeutic decisions [2].
Diffusion tensor imaging (DTI) is a noninvasive method for evaluating diffusivity and directionality of free water molecules. The loss of fractional anisotropy (FA) suggests disintegration of myelin sheath and axons, while increase in apparent diffusion coeficient (ADC) suggests injury to the structures that restrict water diffusion which appear quite earlier and missed by conventional imaging. The FA value in the affected area is significantly lower while the ADC one is higher compared to the apparently unaffected area. Thus, DTI and FA plus ADC calculations are helpful noninvasive clinical techniques that may improve the evaluation of patients with ALD and thereby helping in earlier management [3].
MR spectroscopy reveals decrease in NAA and raised choline compatible with neuronal/axonal loss and enhanced myelin turnover related to demyelination respectively. These findings have been reported in white matter that have a normal appearance on both conventional MR and DT images[4]. MR spectroscopy, therefore has been suggested as most sensitive technique for detecting early abnormalities of demyelination or axonal loss in patients with X-ALD[4].
Differential Diagnosis List
Adrenoleukodystrophy
Final Diagnosis
Adrenoleukodystrophy
References
[1] Moser HW, Loes DJ, Melhem ER, et al (2000) X-linked adrenoleukodystrophy: overview and prognosis as a function of age and brain magnetic resonance imaging abnormality: a study involving 372 patients. Neuropediatrics 31:227239 (PMID: 11204280)
[2] Itoh R, Melhem ER, Mori S, Raymon GV, Moser HW (2002) Diffusion Tensor Brain MR Imaging in X-Linked Adrenoleukodystrophy. Proc. Intl. Soc. Mag. Reson. Med. 10: 791-4
[3] Schneider JFL, IlÂ’yasov KA, Boltshauser E et al (2003) Diffusion Tensor Imaging in Cases of Adrenoleukodystrophy: Preliminary Experience as a Marker for Early Demyelination?. AJNR Am J Neuroradiol 24:8198241 (PMID: 12748077)
[4] Eichler FS, Itoh R, Barker PB (2002) Proton MR Spectroscopic and Diffusion Tensor Brain MR Imaging in X-linked Adrenoleukodystrophy: Initial Experience. Radiology
Case information
| URL: | https://www.eurorad.org/case/8297 |
| DOI: | 10.1594/EURORAD/CASE.8297 |
| ISSN: | 1563-4086 |
Figure 2
Figure 2
Axial FLAIR image shows hyperintensities in the similar regions.
Figure 3
Figure 3
T1W contrast enhanced axial image showing enhancement at the peripheral zones demyelination.
Figure 4
Figure 4
MR spectroscopy: voxel within the demyelination region reveals a high choline (Cho) and corresponding decrease in N Acetyl aspirate (NAA) peak.
Figure 5
Figure 5
Color coded Diffusion Tensor Imaging, shows increased T2 signal intensities in the splenium and optic radiation tracts with corresponding decrease in FA and increase in ADC values as shown in tabulated form below.
Figure 1
Axial T2W image shows bilateral symmetrical increased T2 signal intensities in the parieto-occipital lobes, splenium, and optic radiation tracts.
Figure 2
Axial FLAIR image shows hyperintensities in the similar regions.
Figure 3
T1W contrast enhanced axial image showing enhancement at the peripheral zones demyelination.
Figure 4
MR spectroscopy: voxel within the demyelination region reveals a high choline (Cho) and corresponding decrease in N Acetyl aspirate (NAA) peak.
Figure 5
Color coded Diffusion Tensor Imaging, shows increased T2 signal intensities in the splenium and optic radiation tracts with corresponding decrease in FA and increase in ADC values as shown in tabulated form below.