Repeated Perfusion Scans in Rapid-cycling Bipolar Affective Disorder

Perfusion fMRI is a new magnetic resonance imaging technique being developed to create maps of brain perfusion, i.e. localized blood exchange in brain tissue. A so-called "spin-labeling" technique, it utilizes the intrinsic protons of blood and brain tissue, labeled by special preparation pulses, rather than exogenous tracers injected into the blood. Typically, the method consists of two parts. First, for reference, all the spins in the brain are "labeled" and a series of images acquired to follow their normal return to equilibrium. Second, only the spins in the section of interest are "labeled", and an identical series of images is acquired, this time to observe the more rapid return to equilibrium as "labeled" spins are replaced by unlabeled spins with the exchange of blood. By quantitative comparison of the two series, a map of brain perfusion can be computed.

Background: Functional imaging studies of bipolar affective disorder (BPAD) have suggested that mania may be associated with decreased metabolism in the right temporal and frontal lobes. However, most studies to date have taken single images during extreme mania or depression. We have implemented a perfusion technique (pfMRI) that magnetically tags hydrogen atoms in the blood stream, yielding absolute global and regional perfusion rates. This radiation-free technique allows multiple and serial imaging of the same subject.

Methods: We have serially scanned 3 adults with BPAD (2M, 1F; ave. 13 scans) and 2 healthy controls using this new pfMRI technique. Images were consistently taken at the same brain level (anterior cingulate and prefrontal cortex) over the course of 3 months.

Results: Although data are still being analyzed, initial work suggests that global gray matter perfusion correlated with varying mood states, although the relationship is complex. Regional analysis is in progress.

Conclusion: This ongoing study demonstrates the feasibility of studying global and regional perfusion using the non-invasive, radiation-free pfMRI technique. Although the relationship between perfusion and the mood cycle is complex, this new imaging tool will likely aid in understanding the longitudinal course of BPAD and other neuropsychiatric disorders, generating movies of disease progression and recovery.

The following graphic consists of Patient DAB's and Control PAR's mood function charts. Points above the line represent increased mania. Points below the line represent increased depression. Vertical lines represent days on which subjects were scanned.

The following graphic consists of 7 concurrent scans, with Patient DAB on the left and Control PAR on the right. Red represents increased relative blood perfusion, and blue decreased.

Young Mania rating = 3
Hamilton Depression rating = 19

Young Mania rating = 4
Hamilton Depression rating = 26

Young Mania rating = 3
Hamilton Depression rating = 22

Young Mania rating = 9
Hamilton Depression rating = 23

Young Mania rating = 7
Hamilton Depression rating = 4

Young Mania rating = 4
Hamilton Depression rating = 17

Funded by the Stanley Foundation

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