mercoledì 14 gennaio 2009
Marked right sided cystic encephalomalacia with ex-vacuo dilation of the right lateral ventricle. Essentially entire R ICA distribution. Asymmetric thickening of the right calvarium and hypertrophy of the right frontal sinus.
Associated differential diagnosis: Increased skull thickness
Cerebral atrophy ie following shunt insertion for hydrocephalus.
Chronic severe anemia (e.g. thalassemia, Sickle cell disease.)
Chronic dilantin ingestion.
Osteopetrosis (mainly skull base)
Hyperostosis frontalis interna
Diagnosis: Dyke-Davidoff-Masson syndrome
Cerebral hemiatrophy or Dyke-Davidoff-Masson syndrome is a condition characterized by seizures, facial asymmetry, contralateral hemiplegia or hemiparesis, and mental retardation. These findings are due to cerebral injury that may occur early in life or in utero. Typically the condition is due to middle cerebral artery stroke in utero. However congenital infection and trauma are other etiological factors. Patients may present with a range of clinical manifestations. In some patients such as the case presented, the condition is asymptomatic and is often picked up as an incidental finding.
The radiological features of Dyke-Davidoff-Masson syndrome are unilateral loss of cerebral volume and associated compensatory bone alterations in the calvarium, like thickening, hyperpneumatization of the paranasal sinuses and mastoid cells and elevation of the petrous ridge. Classical findings of the syndrome are present in variable degrees according to the extent of the brain injury. Plain radiographs of the skull are useful in demonstrating diploic space thickening and hyperpneumatization of the paranasal sinuses. CT demonstrates to better effect the osseous changes with a more accurate estimation of both diploic space widening and paranasal sinus changes.
The magnetic resonance (MR) findings of Dyke-Davidoff-Masson syndrome are similar to many of the CT findings encompassing a unilaterally small cerebral hemisphere together with ipsilateral diploic calvarial expansion, elevation of the petrous bone and orbital roof, and hypoplasia/atrophy of the cerebral peduncle.
The pathologic alterations of cerebral tissue and the brainstem are reflected in detail on MR studies. MR findings in addition to the primary vascular insult may include prominence of the cortical sulci and perimesencephalic cistern but some patients demonstrate absence of such generalized sulcal prominence. Although computed tomography (CT) and MR are complimentary, it is felt that MR represents the imaging procedure of choice with respect to the assessment of the etiology and extent of cerebral parenchymal involvement in patients presenting with a clinical combination of congenital or early onset of seizures, hemiparesis/plegia, and/or craniofacial asymmetry.