Skull metastases detecting on arterial spin labeling perfusion: Three case reports and review of literature

RATIONALE: Detection of skull metastases is as important as detection of brain metastases because early diagnosis of skull metastases is a crucial determinant of treatment. However, the skull can be a blind spot for assessing metastases on routine brain magnetic resonance imaging (MRI). To the best of our knowledge, the finding of skull metastases on arterial spin labeling (ASL) has not been reported. ASL is a specific MRI sequence for evaluating cerebral blood flow using magnetized endogenous inflow blood. This study uses ASL as a routine sequence of brain MRI protocol and describes 3 clinical cases of skull metastases identified by ASL. The study also highlights the clinical usefulness of ASL in detecting skull metastases. PATIENT CONCERNS: Three patients with known malignancy underwent brain MRI to evaluate for brain metastases. DIAGNOSES: All of the skull metastases were conspicuously depicted on routine ASL images, and the lesions correlated well with other MRI sequences. INTERVENTIONS: Three patients received palliative chemotherapy. OUTCOMES: Three patients are being followed up regularly at the outpatient department. LESSONS: The routine use of ASL may help to detect lesions in blind spots, such as skull metastases, and to facilitate the evaluation of intracranial pathologies without the use of contrast materials in exceptional situations.