Injury of the dentato-rubro-thalamic tract in a patient with mild traumatic brain injury

Role of Diffusion Tensor Imaging in the Diagnosis of Traumatic Axonal Injury in Individual Patients with a Concussion or Mild Traumatic Brain Injury: A Mini-Review

Present review paper aims to understand role of diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) in diagnosis of traumatic axonal injury (TAI), induced by head trauma, in individual patients with a concussion or mild traumatic brain injury (mTBI). Precise information on presence and severity of TAI in brain is necessary for determining appropriate therapeutic strategies. Several hundred DTI-based studies have reported TAI in concussion or mTBI. Majority of these DTI-based studies have been performed in a group of patients, whereas case studies that have reported TAI in individual patients with a concussion or mTBI are fewer. Summary of these DTI-based studies for individual patients is as follows: DTI can be used as a non-invasive tool for determining presence and severity of TAI in individual patients with concussion or mTBI. However, for diagnosis of TAI in an individual patient, several conditions are required to be met: no past history of head trauma, presence of possible conditions for TAI occurrence during head trauma, development of new clinical features after head trauma, and DTI observed abnormality of a neural structure that coincides with a newly developed clinical feature. However, further studies for a more precise diagnosis of TAI in individual patients should be encouraged.

Injury of the dentato-rubro-thalamic tract in a patient with intentional tremor after mild traumatic brain injury: a case report

OBJECTIVES

We imaged the dentato-rubro-thalamic tract (DRTT) and cortico-ponto-cerebellar tract (CPCT) using diffusion tensor tractography (DTT) to evaluate the cortico-cerebellar-cortical circuit in a patient with tremor in both hands after mild TBI. We found bilateral DRTT injury in the DTT.

METHOD

A 50-year-old male presented with action tremor in both hands 1 week after mild TBI. One month before the visit, the patient had a head injury from a fall on a bus. The patient lost consciousness for 1 min and experienced post-traumatic amnesia for approximately 5 min after the accident. His Glasgow Coma Scale score was 15. The action tremor presented with a frequency of 3 Hz in both hands. No specific lesion was observed with a conventional brain MRI.

RESULTS

DTT, performed 1.5 months after TBI, showed that the right DRTT was not reconstructed and the left DRTT had thinned. However, CPCT integrity was well-preserved in both hemispheres. The tremor disappeared after oral treatment with 30 mg/day indenol. The patient's tremor would have been caused by disruption of the bilateral DRTT following mild TBI.

CONCLUSION

DRTT and CPCT analysis using DTT would be useful for diagnosing abnormal movement problems, including tremor and ataxia, in patients following mild TBI.

Injury of the dentatorubrothalamic tract in patients with post-traumatic tremor following mild traumatic brain injury: a case-control study

Post-traumatic movement disorder is one of the sequelae of traumatic brain injury. The dentatorubrothalamic tract (DRTT) is reported to be involved in the control of movement. Therefore, injury of the DRTT can be accompanied by abnormal movements, including ataxia, tremor, or dystonia. We investigated DRTT injuries in 27 patients who showed post-traumatic tremor in at least one of four extremities following mild traumatic brain injury. We classified DRTT injuries based on diffusion tensor tractography parameters and configuration: type A: the DRTT showed narrowing, type B: the DRTT showed partial tearing, and type C: the DRTT showed discontinuation. Fractional anisotropy and fiber number of the DRTT were significantly decreased in patients compared with the healthy controls. Based on our DRTT injury classification, among the 54 hemispheres of the 27 patients, type A injury occurred in 22 hemispheres (40.7%) of 17 patients, type B injury was present in 15 hemispheres (27.7%) of 10 patients, and type C injury was observed in 8 hemispheres (14.8%) of 6 patients. Our results suggest that diffusion tensor tractography-based evaluation of the DRTT would be useful when determining cause of post-traumatic tremor in patients with mild traumatic brain injury. The study protocol was approved by the Institutional Review Board of Yeungnam University Hospital (YUMC-2018-09-007) on September 5, 2018.

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

We report on a patient with tinnitus who showed injury of auditory radiation following whiplash injury, demonstrated by diffusion tensor tractography (DTT). A 48-year-old male patient suffered from a car crash resulting in flexion-hyperextension injury of his head after being hit from behind by a moving car while waiting at a signal while driving a car. Three days after the car crash, he began to feel tinnitus in both ears and his tinnitus became aggravated with the passage of time. No specific lesion was observed on a conventional brain MRI performed two weeks after the car crash. Although he visited several hospitals, the precise cause of his tinnitus was not detected. Two years after the car crash, he underwent evaluation for his tinnitus at the ear, nose and throat department of a university hospital. The pure tone audiometry was evaluated in a sound-proof room to screen his hearing status for the frequencies of 250-8000 Hz and no specific abnormality was detected. Although he was also tested for speech audiometry, there was also no specific abnormality. In order to assess his tinnitus, a tinnitogram was conducted to evaluate the frequency content and the loudness. His tinnitus was characterized at an intensity of 40 dB and a frequency of 4000 Hz. However, no abnormality was observed in either ear on physical examination. On DTT, the auditory radiation showed severe narrowing and tearing in both hemispheres. To summarize, neural injury of the auditory radiation was demonstrated in a patient with tinnitus following whiplash injury, using DTT.

Central Pain Due to Injury of the Spinothalamic Tract Misdiagnosed as Complex Regional Pain Syndrome: A Case Report

Objectives: We report on a patient with whiplash injury who had central pain, due to injury of the spinothalamic tract (STT), but who was misdiagnosed as complex regional pain syndrome (CRPS). Case description: While a minivan in which a 43-year-old female was seated in the passenger seat was stopped for a signal, a truck collided with the minivan from behind, and the minivan then repeatedly collided with trucks in front and behind the minivan. Her head repeatedly struck the minivan seat resulting in whiplash injuries. After onset, she felt pain in both legs with mild motor weakness in all four extremities and memory impairment. Eight years after onset, she was diagnosed at a university hospital as CRPS type 1 with the clinical features of hyperalgesia and mild edema and motor weakness of both legs. She visited another university hospital nine years after onset and complained of pain in the right arm and both legs, constant tingling and burning pain along with allodynia and hyperalgesia. She also showed mild weakness in the four extremities, mild edema of both legs, and memory impairment. On diffusion tensor tractography (DTT), the left spinothalamic tract (STT) showed marked narrowing, and the right STT revealed mild narrowing and partial tearing. In addition, partial tears were observed in both corticospinal tracts and the right corticoreticulospinal tract. Discontinuations were observed in the left corticoreticulospinal tract and the left fornical crus. Conclusion: Injury of the STT was demonstrated on DTT in a patient with central pain following whiplash injury. Previously, the patient was misdiagnosed as CRPS.

Excessive Daytime Sleepiness and Injury of the Ascending Reticular Activating System Following Whiplash Injury

Objectives: This study investigated injuries of the ascending reticular activating system (ARAS) following whiplash injury, in patients with excessive daytime sleepiness (EDS). Methods: Twenty-three patients with whiplash injury and 26 healthy control subjects were recruited for this study. Epworth Sleepiness Scale (ESS) was used for evaluating sleepiness. According to the ESS score, the patients were classified into two groups: subgroup A - ESS score <10, and subgroup B - ESS score ≥10. Three components of the ARAS (lower dorsal, lower ventral, and upper) were evaluated for fractional anisotropy (FA) and tract volume (TV). Results: No significant differences were observed in the FA and TV values of the lower dorsal and upper ARAS between the patient and control groups (p > 0.05). Conversely, the values of FA and TV in the lower ventral ARAS of the patient group were significantly lower than those of the control group (p < 0.05). Comparing the values of subgroups A and B, the TV value of subgroup B was significantly lower than subgroup A (p < 0.05). However, no significant differences were observed in the values of the FA and TV in the lower dorsal and upper ARAS, and the FA value in the lower ventral ARAS (p > 0.05). Conclusions: We found significant injury of the lower ventral ARAS in EDS patients with whiplash injury. These results suggest that diffusion tensor tractography (DTT) could provide useful information for detecting injuries of the ARAS following whiplash injury, in patients with EDS.

A Review of Traumatic Axonal Injury following Whiplash Injury As Demonstrated by Diffusion Tensor Tractography

Whiplash is a bony or soft tissue injury resulting from an acceleration–deceleration energy transfer in the neck. Although patients with whiplash injury often complain of cerebral symptoms, and previous studies have reported evidence indicating brain injury, such an association has not been clearly elucidated. Traumatic axonal injury (TAI) is tearing of axons due to indirect shearing forces during acceleration, deceleration, and rotation of the brain or to direct head trauma. Diffusion tensor imaging (DTI) has a unique advantage to detect TAI in patients whose conventional brain CT or magnetic resonance imaging (MRI) results were negative following head trauma. Since the introduction of DTI, six studies using diffusion tensor tractography (DTT) based on DTI data have reported TAI in patients with whiplash injury, even though conventional brain CT or MRI results were negative. A precise TAI diagnosis in whiplash patients is clinically important for proper management and prognosis. Among the methods employed to diagnose TAI in the six previous studies, the common diagnostic approach for neural tract TAI in individual patients with whiplash injury were (1) whiplash injury history due to car accident; (2) development of new clinical symptoms and signs after whiplash injury; (3) evidence of neural tract TAI in DTT results, mainly via configurational analysis; and (4) coincidence of newly developed clinical manifestations and the function of injured neural tracts. All six studies were individual patient case studies; therefore, further prospective studies involving larger number of subjects should be encouraged.

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

RATIONALE

We report on a patient with injury of the cortico-ponto-cerebellar tract (CPCT) following mild traumatic brain injury (TBI), diagnosed by diffusion tensor tractography (DTT).

PATIENT CONCERNS

A 53-year-old female patient was injured in a car crash. While under treatment at a local medical center for headache, mild motor weakness, and cognitive impairment that developed following the car crash, she fell, hitting her head on the ground, about six weeks after the car crash.

DIAGNOSES

Approximately three months after the car crash, she began to show tremor on both hands and mild truncal ataxia. Twenty months after the car crash, when she underwent neurological evaluation at the rehabilitation department of a university hospital, she presented with mild resting and intentional tremor on both hands, and mild truncal ataxia.

INTERVENTIONS

N/A.

OUTCOMES

On 20-month DTT, the left CPCT showed tearing at the level of the subcortical white matter and pons, and discontinuation at the cerebellar portion. However, the integrity of the DRTT was well-preserved in both hemispheres.

LESSONS

Using DTT, injury of the CPCT was demonstrated in a patient with ataxia and tremor following mild TBI.

Aggravation of an injured dentato-rubro-thalamic tract in a patient with mild traumatic brain injury: A case report

RATIONALE

We report on a patient with mild traumatic brain injury (TBI) by follow-up diffusion tensor tractography (DTT), and observed for approximately nine monthsby serial diffusion tensor tractography (DTT).

PATIENT CONCERNS

A 66-year-old male patient was injured in a car crash. Approximately four weeks after the crash, he developed a tremor in the right hand and leg. His symptoms worsened over time.

DIAGNOSES

Approximately six months after the crash, he developed a mild tremor in the left hand. Nine months after the crash, he manifested severe tremor in his right hand, mild resting and intentional tremor in his left hand and both legs, and mild trunkal ataxia.

INTERVENTIONS

N/A.

OUTCOMES

On 3-week DTT, well reconstructed DRTTs were observed in both hemispheres, except for the thinned lower portion of the right DRTT. On 9-month DTT, the right lower DRTT had thinned compared with the 3-week DTT and showed a disruption at the upper portion. The left DRTT showed thinning in the lower portion and tearing in the upper portion compared with 3-week DTT.

LESSONS

Aggravation of an injured DRTT was demonstrated in a patient with mild TBI, using serial DTT examination.

Apathy Due to Injury of the Prefrontocaudate Tract Following Mild Traumatic Brain Injury

In this study, we report on a patient who developed apathy resulting from injury to the prefrontocaudate tract following mild traumatic brain injury (TBI), which was observed on diffusion tensor tractography (DTT). A 46-year-old female patient was involved in a bus accident. Her history included intracerebral hemorrhage (ICH) in the left putamen 4 years ago before the head trauma, and her family reported that she had fully recovered. She developed apathy after the TBI, worsening over time. Decreased neural connectivity of the left caudate nucleus (CN) to the left upper medial prefrontal cortex (PFC) resulting from the ICH was observed on the pre-TBI-DTT, whereas on the post-TBI-DTT (28 months after TBI), the neural connectivity of the left CN to the left upper medial PFC was increased, whereas that to the left lower medial PFC and orbitofrontal cortex was decreased. In the right hemisphere, decreased neural connectivity of the CN to the medial PFC and orbitofrontal cortex was observed on the post-TBI-DTT compared with the pre-TBI-DTT. Injury of the prefrontocaudate tract was observed in a patient with old ICH who developed apathy following mild TBI, using DTT.

Injury of the dentato-rubro-thalamic tract in patients with cerebellar infarct: Case report

RATIONALE

Several studies using diffusion tensor tractography (DTT) have reported on injury in the dentato-rubro-thalamic tract (DRTT) in patients with brain injury. However, there is no study of injury in the DRTT following cerebellar infarct. We report on patients with injury in the DRTT following cerebellar infarct, demonstrated on DTT.

PATIENT CONCERNS

Three patients with cerebellar infarct were enrolled in this study. Diffusion tensor imaging data were acquired at 3 weeks (patient 1) and 2 weeks (patients 2 and 3) after onset and the DRTT was reconstructed. The Scale for Assessment and Rating of Ataxiaand the Functional Ambulation Category were used for evaluation of ataxia and gait function.

DIAGNOSES AND OUTCOMES

With clinical evaluation, patient 1 scored 18, patient 2 scored 22, and patient 3 scored 28 points on the Scale for Assessment and Rating of Ataxia. On the Functional Ambulation Category patient 1 scored 2, patient 2 scored 2, and patient 3 scored 1 point. DRTT abnormalities were as follows: discontinuation (the upper portion of the left DRTT in the patient 1), narrowing (the lower portion of the left DRTT in patient 2, and the whole right DRTT in the patient 3), and nonreconstruction (the left DRTT in the patient 3).

LESSONS

Using DTT, we demonstrated injury in the DRTT in 3 patients with severe ataxia following cerebellar infarct. We believe that evaluation of the DRTT would be helpful in patients who develop ataxia following cerebellar infarct.

Severe ataxia due to injuries of neural tract detected by diffusion tensor tractography in a patient with pontine hemorrhage: A case report

RATIONALE

We examined injuries of the dentato-rubro-thalamic tract (DRTT), cortico-ponto-cerebellar tract (CPCT), dorsal spinocerebellar tract (SCT), and inferior cerebellar peduncle (ICP) in a patient with severe ataxia following bilateral tegmental pontine hemorrhage (PH), using diffusion tensor tractography (DTT).

PATIENT CONCERNS

A 75-year-old female patient underwent conservative management for bilateral tegmental PH. She presented with moderate motor weakness, severe resting and intentional tremor on both hands, and severe truncal ataxia (Scale for Assessment and Rating of Ataxia [25 points/0-40 points: a higher score indicates a worse state]), and she was not able to sit independently.

DIAGNOSES AND OUTCOMES

On DTT taken at 2 weeks after initial presentation, both DRTTs and the left dorsal SCT were not reconstructed, whereas the CPCTs showed thinning of the entire pathways between the primary sensorimotor cortex and cerebellum in both hemispheres. The right ICP was discontinued at the transverse cerebellar branch of the ICP and thinning of the left ICP was observed in the vertical and transverse cerebellar branch of the ICP.

LESSONS

Using DTT, concurrent injuries of the DRTT, CPCT, dorsal SCT, and ICP were demonstrated in a patient with severe ataxia following PH. Our result suggests the necessity of evaluation of these neural tracts in patients who develop ataxia after brain injury.

Injury of the dorsolateral prefronto-thalamic tract in a patient with depression following mild traumatic brain injury: A case report

BACKGROUND

Depression, a prevalent psychiatric disorder, is associated with abnormality in the prefrontal cortex, particularly the left dorsolateral prefrontal cortex. In this study, we report on a patient with severe depression who showed injury of the dorsolateral prefronto-thalamic tract following mild traumatic brain injury, which was demonstrated by diffusion tensor tractography (DTT).

METHODS AND RESULTS

A 63-year-old female patient suffered an in-car accident. The patient lost consciousness for approximately 10 minutes and experienced posttraumatic amnesia approximately 30 minutes from the time of the accident. Her Glasgow Coma Scale score was 15. No specific lesion was observed on the conventional brain magnetic resonance imaging. Since the onset of head trauma, she had shown continuous depression and on 32 month evaluation, she exhibited severe depression (Beck Depression Inventory-II: 42 [full score: 63 score] and Patient Health Questionnaire-9: 24 [full score: 27 score]).

RESULTS

On 32-month DTT, partical tearing of the dorsolateral prefronto-thalamic tract was observed in the right hemisphere and thinning in the left hemisphere.

CONCLUSION

Injury of the dorsolateral prefronto-thalamic tract was demonstrated in a patient with depression following mild traumatic brain injury, using DTT. We believe that injury of the dorsolateral prefronto-thalamic tract might be a pathogenetic mechanism of depression in patients with brain injury.

Injury of the inferior cerebellar peduncle in patients with mild traumatic brain injury: A diffusion tensor tractography study

OBJECTIVES

No study on injury of the inferior cerebellar peduncle (ICP) in patients with mild traumatic brain injury (mTBI) has been reported. This study, using diffusion tensor tractography (DTT), attempted to demonstrate injury of the ICP in patients with mTBI.

METHODS

Three patients with mTBI resulting from a car accident and 18 normal healthy control subjects were enrolled in this study. Diffusion tensor imaging data were acquired at 2 months (patient 1) and 3 months (patients 2 and 3) after onset and the ICP was reconstructed. The Balance Error Scoring System was used for evaluation of balance at the same time diffusion tensor imaging scanning was performed.

RESULTS

The ICPs were discontinued at the upper portion of the vertical cerebellar branch and the transverse cerebellar branch (patient 1) and the proximal portion of the transverse cerebellar branch (patients 2 and 3) compared to the normal control subjects. Regarding DTT parameters, in the three patients, the fibre number of the ICPs was decreased by more than 2 SD compared with those of subjects in the control group.

CONCLUSION

Evaluation of the ICP using DTT would be useful in patients with a balance problem after mTBI.