Irreducible anteromedial radial head fracture-dislocation: value of pre-operative magnetic resonance imaging.

We describe a case of an anteromedial fracture-dislocation of the radial head in an adult patient, which was initially irreducible using closed means, and remained challenging to reduce despite open surgery. Further advanced CT/MRI revealed entrapment of the radial head due to the interposition of the brachialis tendon posteriorly, thereby preventing sustained reduction. While three other cases of irreducible anteromedial radial head dislocation due to the brachialis tendon have been reported in the English surgical literature, none of the imaging findings have been described in the radiological literature. Only one other case published in a surgical journal briefly demonstrated pre-operative MRI imaging. We would like to share the value of pre-operative MRI in this rare presentation, which would be helpful in diagnosing not only cases with interposition of the brachialis tendon, but potentially other types of soft tissue interposition which also limit closed reduction. To the best of the authors' knowledge, this would be the first report on the imaging findings in a radiological journal. Awareness of this phenomenon would assist radiologists in the diagnosis and management of this rare condition.

Can CT angiography rule out aneurysmal subarachnoid haemorrhage in CT scan-negative subarachnoid haemorrhage patients?

Current management guidelines for CT scan-negative subarachnoid haemorrhage (SAH) patients recommend cerebral digital subtraction angiography (DSA). We aimed to investigate the utility of CT angiography (CTA) as a substitute for DSA in these patients. We included patients who presented with SAH confirmed by spectrophotometric xanthochromia analysis of cerebrospinal fluid (CSF) whereby the CT scan was negative. Electronic records were reviewed to collect data on non-contrast CT scan, CTA and DSA results. Patients without DSA or with other explanations for CSF xanthochromia were excluded. Sixty-three patients with CT scan-negative SAH were included. The diagnosis of SAH was confirmed by CSF analysis. All 63 patients underwent both DSA and CTA. Using DSA as the benchmark, CTA demonstrated a negative predictive value, positive predictive value, sensitivity and specificity of 98%, 82%, 90% and 96%, respectively, for the detection of intracranial aneurysms. CTA correctly identified patients in whom there were no underlying aneurysms responsible for SAH, with one patient with suspected dissection referred for further evaluation using MRI and DSA.