SUMMARY:We present findings on MR imaging in 5 patients with autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). In the literature, early atrophy of the superior vermis as well as progressive atrophy of the cerebellar hemispheres and cervical cord was described. We found linear hypointensity on T2 and T2 fluid-attenuated inversion recovery-weighted images in the pons in all of our 5 patients. Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) was first described in 1978 as a recessive form of spastic ataxia found in Quebec, Canada. To this day, there are more than 300 affected people in the Charlevoix-Saguenay-LacSt-Jean region, where the carrier frequency is estimated to be 1 in 22 with an equal male-to-female ratio.1 The ARSACS syndrome has shown a consistent pattern of clinical symptoms and electrophysiologic and morphologic findings that have led to the identification of the responsible gene localized on chromosome 13q. 2Since then, several cases have been described in other countries with new mutations and some variations in clinical signs and evolution.3 On imaging studies, such as CT or MR imaging, early atrophy of the superior vermis is the predominant finding, followed by progressive atrophy of the cerebellar hemispheres and the spinal cord. The atrophy of the superior vermis is common in both hereditary and acquired cerebellar ataxias but occurs more precociously in ARSACS, which suggests that it might be a congenital feature. 1,3 In this report, MR imaging in our 5 patients demonstrated linear hypointensity on T2-and T2 fluid-attenuated inversion recovery (FLAIR)-weighted images in the pons that, so far, has not been described previously. These changes could help diagnose ARSACS earlier in preschool children, in whom the disease is often mistaken for cerebral palsy. Case ReportsCase 1. A 9-year-old girl first presented with slight ataxia, increased deep tendon reflexes and clonus in the lower limbs on physical examination at 3 years old. The history revealed a normal pregnancy and delivery in the mother. The father originated from the Charlevoix region. The patient also had a 6-year-old sister who showed similar manifestations. Imaging demonstrated discrete atrophy of the superior vermis (Fig 1) and linear hypointensity on proton density and T2-weighted images in the pons, not seen on T1-weighted images. Genetic diagnosis of ARSACS was confirmed.Case 2. A 9-year-old girl presented with early difficulty with gait and a tendency to fall. The history also revealed a normal pregnancy and delivery in the mother, without a family history of neurodegenerative disease. Both parents were from an area close to the Saguenay region. When she was 8 years old, the physical examination of the girl revealed a slight dysarthria, dysmetria on a finger-to-nose test, slowing of fast repetitive movements, and increased tricipital reflex. When she was 9 years old, increased deep tendon reflexes in the lower limbs were present, and she also experienced saccadic ocular movements during volunta...

Postpartum sacral insufficiency fracture is an uncommon occurrence that is often under-diagnosed because its symptoms of low back, buttock and groin pains may initially be attributed to physiologic biomechanical changes caused by pregnancy or to intervertebral disc disease. We present a case of bilateral sacral insufficiency fractures in a 37-year-old postpartum woman with osteopenic bone mineral density confirmed by dual energy X-ray absorptiometry. The symptoms were initially suspected to be of discogenic cause, and the fractures were incidentally appreciated at the edge of a lumbar spine magnetic resonance image. Therefore, it is important to keep in mind this potential diagnosis when examining imaging studies of postpartum patients. For women who present other risk factors of osteoporosis, imaging of the entire sacrum should be part of the imaging studies. If sacral stress fractures are diagnosed, further evaluation for bone mineral density and underlying metabolic bone disease is recommended.

Isolated avulsion fracture of the extensor carpi radialis longus (ECRL) tendon is a rare and poorly understood injury. We present a unique case of a 45-year-old male who fell on his flexed right hand. He presented with a subtle but extremely painful mass on the dorsum of his wrist. Ultrasound (U/S) imaging of the mass revealed an avulsed bone fragment attached to the ECRL tendon, confirming the clinical suspicion of an ECRL avulsion injury. Computed tomography and magnetic resonance imaging are well-documented imaging modalities to detect tendon avulsions. As demonstrated by this case report, U/S is an excellent diagnostic tool for ECRL rupture, a cost-effective alternative that provides real-time dynamic examination of hand injuries. To our knowledge, this is the first case of ECRL avulsion diagnosed by U/S. The purpose of this case report is to educate the reader on detection and diagnosis of ECRL tendon avulsion using U/S, a time-efficient and cost-effective imaging modality that is infrequently used for this purpose.

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