June 18, 2015
An 18-year-old man was found hanging and without a pulse. After resuscitation he was admitted to the ICU, and an MRI was obtained to aid with prognosis.
Incomplete Hanging with Regional Hyperperfusion
- Background: Hanging remains a common method of suicide in the United States, with a paucity of literature concerning the general and advanced MR imaging characteristics.
- Key Diagnostic Features:
- Focal super-physiologic on ASL likely results from loss of vascular resistance (aka. luxury perfusion), reflecting a transient or permanent brain injury resulting in accumulation of ASL tracer in dilated arteries and veins. This finding is considered to be associated with an unfavorable clinical prognosis.
- Decreased conspicuity of cortical veins on SWI minIP images may be due to: 1) increased regional hyperemia and rapid mean transit times through the capillary bed resulting in decreased oxygen extraction, or 2) a decreased ability of ischemic/infarcted tissue to adequately extract oxygen at the capillary level. Both can result in focally increased concentrations of venous oxyhemoglobin and decreased venous deoxyhemoglobin suggestive of physiological shunting.
- Analysis of complementary MRI sequences can explain in vivo physiology and provide useful information following hypoxic injury. The deep gray nuclei (notably the posterior putamina) and cerebral cortex are preferentially affected by hypoxic injury, as evidenced on T2WI and DWI, as well as ASL and SWI; the latter may provide additional physiologic information in evaluating hypoxic injury.
