midline shift
Displacement of brain structures from their normal central position, typically due to mass effect from tumor, edema, or hemorrhage.
Full Definition
Midline shift represents a critical radiological finding in neurosurgical oncology, indicating displacement of normally central brain structures such as the falx cerebri, third ventricle, or septum pellucidum from the anatomical midline. This shift typically results from mass effect caused by tumors, surrounding edema, hemorrhage, or hydrocephalus. The degree of midline shift, measured in millimeters on axial imaging, correlates with increased intracranial pressure and neurological deterioration. Significant midline shift (typically >5mm) often indicates the need for urgent surgical intervention to prevent brain herniation. The finding helps guide treatment decisions and assess the urgency of surgical decompression.
Usage
Usage note: Always measured in millimeters; values >5mm typically considered clinically significant.
In Context
- "CT imaging revealed 8mm of midline shift secondary to tumor-associated edema." — radiology report
- "The patient requires emergency surgery due to significant midline shift and declining mental status." — urgent consultation