<p>Crossed cerebellar diaschisis (CCD) was originally defined as depression of metabolism and blood flow in the cerebellar hemisphere contralateral to a supratentorial lesion in hemispheric stroke. Arterial spin labeling (ASL) magnetic resonance (MR) perfusion imaging with multiple postlabeling delays (PLDs) is useful for non-invasive detection of the hemodynamics of (peri)ictal hyperperfusion. Previous reports using ASL with a 3-Tesla (T) MR machine showed crossed cerebellar hyperperfusion (CCH) associated with supratentorial hyperperfusion, probably through the same mechanism as CCD, in patients with epilepsy during the ictal period. However, there are no reports on 1.5-T ASL, which is widely used in neuroemergencies. Here we evaluated the hemodynamics of (peri) ictal hyperperfusion and CCH using 1.5-T ASL in an 84-year-old man with right lesional temporal lobe epilepsy who experienced three episodes of convulsive status epilepticus (CSE). The ASL obtained was evaluated on fusion images with conventional MR images and subtracting ictal-interictal 1.5-Tesla ASL images co-registered to conventional MR images. Repeated ASL examinations performed 1 day after the first CSE, immediately after the second CSE, and during the third CSE demonstrated CCH in addition to right hemispheric hyperperfusion. The CCH became progressively stronger with increase in visualization of right hemispheric hyperperfusion. Furthermore, both showed the same hemodynamics; the ASL signals increased at PLD of 1.5 s and gradually decreased at PLDs of 1.75 s and 2.0 s. Increase in signal intensity was noted on the right side of the midbrain and pons as well as somwehat in the contralateral cerebellar peduncle. In this case, 1.5-T ASL demonstrated that the cortico-pontine-cerebellar pathway was strongly involved in the development of CCH in epilepsy similar to CCD in stroke.</p>