A 5-minute, ultra-fast MRI can identify and diagnose intracranial abnormalities as effectively as a head CT, making it a good alternative for some patients with neurological emergencies.
According to Philipp Kazmierczak, M.D., a radiologist with University Hospital in Munich and lead author of a study published this week in Investigative Radiology, patients with acute neurological symptoms account for roughly 15 percent of emergency department cases. Consequently, quick and accurate diagnosis is critical.
The study was funded by Siemens Healthineers in Germany and evaluated the company’s five-sequence GOBrain protocol.
Based on the findings, investigators determined a less-than five-minute ultra-fast MRI has the equivalent sensitivity and specificity of a standard-length protocol when examining neurological emergencies, 94 percent and 100 percent, respectively. Not only did this scan pinpoint more lesions than CT, but it also affected treatment in 10 percent of patients.
“In the majority of institutions, CT of the head is the imaging modality of choice to exclude intracranial pathologies in the emergency setting, as it is fast and widely available,” Kazmierczak said. “Despite the high diagnostic standard of modern CT, MRI remains the reference standard for the detection and differential diagnosis of intracranial pathologies.”
But, long acquisition times of multi-sequence MRI protocols have delayed diagnosis and treatment, limiting use in emergency settings.
To test ultra-fast MRI image quality and diagnostic capability, as well as how it compares to CT, researchers examined 449 patients who presented to the emergency department with acute non-traumatic neurological symptoms between January and October 2018. Patients were excluded for three reasons: a CT showed correlating signs or symptoms, intravenous thrombolysis or mechanical recanalization had occurred, or if they had contraindications to MRI. The team also excluded unstable patients.
Of the 449 admitted patients 238 underwent head CT. CT explained symptoms for 40 patients, and additional imaging was excluded for another 71 individuals, leaving 69 with negative non-contrast CTs. Those patients, then, had 3T non-contrast MRI scans with two protocols of five standard sequences – a standard-length 15:11 minute protocol and an ultra-fast 4:33 minute scan. Two independent, blinded neuroradiologists analyzed the scans.
According to study results, the neuroradiologists identified 93 additional lesions, including acute ischemia, edema, and hemorrhage or microbleeds, with ultra-fast MRI when compared to CT alone. An additional eight lesions – five microbleeds and two acute ischemia cases – were detected only with standard MRI, but they weren’t clinically significant.
The ultra-fast MRI findings also altered treatment for six patients. All were admitted to the stroke unit, and three received acetylsalicylic acid.
Ultimately, Kazmierczak said, ultra-fast MRI is a viable option over head CT for some patients.
“It was demonstrated that image quality and diagnostic performance of ultra-fast MRI are non-inferior to the standard-length brain MRI protocol,” he said. “Our data provide evidence for the standard use of ultra-fast MRI as an alternative to CT for the detection and differential diagnosis of intracranial pathologies in acute neurological emergencies.”