Neurological picture. "Puppy sign" indicating bilateral dissection of internal carotid artery.

Segregation of a missense mutation in the amyloid precursor protein gene with familial Alzheimer's disease. Lewy bodies in Alzheimer's disease: a neuropathological review of 145 cases using alpha-synuclein immunohistochemistry. Lewy body pathology in familial Alzheimer's disease: evidence for disease and mutation-specific pathologic phenotype. Lewy body pathology in late-onset familial Alzheimer's disease: a clinicopathological case series. Estimation of the genetic contribution of presenilin-1 and-2 mutations in a population-based study of presenile Alzheimer disease. High prevalence of pathogenic mutations in patients with early onset dementia detected by sequence analyses of four different genes. A 66-year-old patient presented with marked headache. Neurological examination was unremarkable. Fat saturated T1 weighted magnetic resonance showed bilateral dissection of the extracranial internal carotid artery. Dissections are among the most frequent causes of young onset stroke. 1 They may, however, be difficult to diagnose only on the basis of history and clinical signs, and even standard brain imaging may not suffice. 2 Fat saturated T1 weighted magnetic resonance is the method of choice to detect mural haematoma and residual lumen. 1 Bilateral internal carotid artery dissection may resemble the face of a puppy in axial orientated sections, and awareness of this ''puppy sign'' may ease the quick visual diagnosis (fig 1). Bilateral internal carotid artery dissection mimicking inflammatory demyelinating disease. Figure 1 Axial fat saturated T1 weighted magnetic resonance of bilateral internal carotid artery (ICA) dissection (A) resembling the face of a dog (B). (a) Ears = masseter muscles; (b) eyes = ICA, sclera = subintimal haematoma, pupil = residual lumen; (c) snout tip = upper cervical spinal cord; (d) snout = cervical spinal canal; (e) flew = longissimus capitis muscle; and (f) throat = subcutaneous fat tissue.