Diagnostic History of Traumatic Axonal Injury in Patients with Cerebral Concussion and Mild Traumatic Brain Injury

Abstract

Highlights• Cerebral concussion and mild traumatic brain injury (TBI) have been used interchangeably, although the two terms have different definitions.• Traumatic axonal injury (TAI) is a more severe subtype of TBI than concussion or mild TBI.• In this review article, we reviewed the history of TAI in patients with concussion and mild TBI. ABSTRACTCerebral concussion and mild traumatic brain injury (TBI) have been used interchangeably, although the two terms have different definitions. Traumatic axonal injury (TAI) is a more severe subtype of TBI than concussion or mild TBI. Regarding the evidence of TAI lesions in patients with concussion or mild TBI, since the 1960's, several studies have reported on TAI in patients with concussion who showed no radiological evidence of brain injury by autopsy. However, conventional CT and MRI are not sensitive to detection of axonal injury in concussion or mild TBI, therefore, previously, diagnosis of TAI in live patients with concussion or mild TBI could not be demonstrated. With the development of diffusion tensor imaging (DTI) in the 1990's, in 2002, Arfanakis et al. reported on TAI lesions in live patients with mild TBI using DTI for the first time. Subsequently, hundreds of studies have demonstrated the usefulness of DTI in detection of TAI and TAI lesions in patients with concussion or mild TBI. In Korea, the term "TAI" has rarely been used in the clinical field while diffuse axonal injury and concussion have been widely used. Rare use of TAI in Korea appeared to be related to slow development of DTI analysis techniques in Korea. Therefore, we think that use of DTI analysis techniques for diagnosis of TAI should be facilitated in Korea.

Diagnosis of Tinnitus Due to Auditory Radiation Injury Following Whiplash Injury: A Case Study

“…Severe narrowing and tearing of both the auditory radiations on DTT indicates neural injuries of both auditory radiations. Because no definite brain lesion was detected on conventional brain MRI, traumatic axonal injury (TAI) appeared to be the most likely pathogenetic mechanism [23][24][25][26]. We think that these injuries of the auditory radiations might be at least partly related to the tinnitus in this patient.…”

Diagnosis of Tinnitus Due to Auditory Radiation Injury Following Whiplash Injury: A Case Study

“…Severe narrowing and tearing of both the auditory radiations on DTT indicates neural injuries of both auditory radiations. Because no definite brain lesion was detected on conventional brain MRI, traumatic axonal injury (TAI) appeared to be the most likely pathogenetic mechanism [23][24][25][26]. We think that these injuries of the auditory radiations might be at least partly related to the tinnitus in this patient.…”

Injury of the cortico-ponto-cerebellar tract in a patient with mild traumatic brain injury

“…Because no definite brain lesion was detected on conventional brain MRI, traumatic axonal injury (TAI) was the most likely pathogenetic mechanism in this patient. [ 21 – 24 ] However, we could not discern whether this injury resulted from the car crash or the later fall. The delayed onset (3 months after the car crash and 6 weeks after the fall) of ataxia and tremor suggests that the TAI was a secondary injury in which axons were not initially damaged, but injured by a sequential process of impaired axoplasmic transport, continued axonal swelling, and disconnection.…”

Injury of the Spinothalamic Tract Following Whiplash Injury: A Diffusion Tensor Tractography Study

“…Therefore, the decrease of TV without change of FA value in the patient group appeared to indicate injury of the STT. Because the conventional brain MRI, electromyography, and nerve conduction studies in the patient group were normal, traumatic axonal injury (TAI) was the most likely pathogenic mechanism for injuries of the STT [37][38][39][40].…”

Diagnosis of Tinnitus Due to Auditory Radiation Injury Following Whiplash Injury: A Case Study

“…Severe narrowing and tearing of both the auditory radiations on DTT indicates neural injuries of both auditory radiations. Because no definite brain lesion was detected on conventional brain MRI, traumatic axonal injury (TAI) appeared to be the most likely pathogenetic mechanism [23][24][25][26]. We think that these injuries of the auditory radiations might be at least partly related to the tinnitus in this patient.…”

Injury of the cortico-ponto-cerebellar tract in a patient with mild traumatic brain injury

“…Because no definite brain lesion was detected on conventional brain MRI, traumatic axonal injury (TAI) was the most likely pathogenetic mechanism in this patient. [ 21 – 24 ] However, we could not discern whether this injury resulted from the car crash or the later fall. The delayed onset (3 months after the car crash and 6 weeks after the fall) of ataxia and tremor suggests that the TAI was a secondary injury in which axons were not initially damaged, but injured by a sequential process of impaired axoplasmic transport, continued axonal swelling, and disconnection.…”

Injury of the Spinothalamic Tract Following Whiplash Injury: A Diffusion Tensor Tractography Study

“…Therefore, the decrease of TV without change of FA value in the patient group appeared to indicate injury of the STT. Because the conventional brain MRI, electromyography, and nerve conduction studies in the patient group were normal, traumatic axonal injury (TAI) was the most likely pathogenic mechanism for injuries of the STT [37][38][39][40].…”

Diagnosis of Tinnitus Due to Auditory Radiation Injury Following Whiplash Injury: A Case Study

“…Severe narrowing and tearing of both the auditory radiations on DTT indicates neural injuries of both auditory radiations. Because no definite brain lesion was detected on conventional brain MRI, traumatic axonal injury (TAI) appeared to be the most likely pathogenetic mechanism [23][24][25][26]. We think that these injuries of the auditory radiations might be at least partly related to the tinnitus in this patient.…”

Injury of the cortico-ponto-cerebellar tract in a patient with mild traumatic brain injury

“…Because no definite brain lesion was detected on conventional brain MRI, traumatic axonal injury (TAI) was the most likely pathogenetic mechanism in this patient. [ 21 – 24 ] However, we could not discern whether this injury resulted from the car crash or the later fall. The delayed onset (3 months after the car crash and 6 weeks after the fall) of ataxia and tremor suggests that the TAI was a secondary injury in which axons were not initially damaged, but injured by a sequential process of impaired axoplasmic transport, continued axonal swelling, and disconnection.…”

Injury of the Spinothalamic Tract Following Whiplash Injury: A Diffusion Tensor Tractography Study

“…Therefore, the decrease of TV without change of FA value in the patient group appeared to indicate injury of the STT. Because the conventional brain MRI, electromyography, and nerve conduction studies in the patient group were normal, traumatic axonal injury (TAI) was the most likely pathogenic mechanism for injuries of the STT [37][38][39][40].…”