2009 年 32 巻 1 号 p. 7-17
Over the past decade, imaging technologies have been successfully developed and many imaging modalities have emerged in the clinical field. In this article, the symposium entitled “Brain imaging in traumatic brain injury” held in the 32nd annual meeting of the Japan Society of Neurotraumatology is reviewed and recent advancement of neuroimaging in head trauma is discussed. In the symposium, six investigators presented the role and the usefulness of their imaging modalities including morphological imaging using CT angiography and 3-tesla MRI, functional imaging using diffusion tensor imaging, blood flow imaging using SPECT, and molecular imaging using PET in the acute or chronic stage after traumatic brain injury (TBI). They demonstrated that the use of modern imaging tools could improve early recognition of primary damage and understanding the underlying mechanisms of secondary damage after TBI.
CT scanning is the most important imaging technique for acute TBI, giving rapid information and being part of a general trauma work up in an emergency situation. Guidelines for CT scanning in minor head injury have been proposed, however, a recent validation study has failed to show the cost-effectiveness. MRI is an imaging technique for evaluating the full extent of brain injury. Information on brain injury especially diffuse axonal injury is obtained by several MRI sequences such as fluid-attenuated inversion recovery, T2*-weighted imaging and diffusion-weighted imaging. Diffusion tensor imaging is able to show long tract damage and has been reported to correlate with prognosis. Several techniques are suited to studying cerebral blood flow and metabolism, including single photon emission CT (SPECT) and positron emission tomography (PET). Each imaging modality has merits and demerits and should be used complementary to each other. There are several molecular imaging techniques available in TBI, which may give us more information about the injury and prognosis for recovery.
