Diffusion tensor imaging findings of optic radiation in patients with putaminal hemorrhage

A Deep Learning Model for Automatic Segmentation of Intraparenchymal and Intraventricular Hemorrhage for Catheter Puncture Path Planning

Intracerebral hemorrhage is the subtype of stroke with the highest mortality rate, especially when it also causes secondary intraventricular hemorrhage. The optimal surgical option for intracerebral hemorrhage remains one of the most controversial areas of neurosurgery. We aim to develop a deep learning model for the automatic segmentation of intraparenchymal and intraventricular hemorrhage for clinical catheter puncture path planning. First, we develop a 3D U-Net embedded with a multi-scale boundary aware module and a consistency loss for segmenting two types of hematoma in computed tomography images. The multi-scale boundary aware module can improve the model's ability to understand the two types of hematoma boundaries. The consistency loss can reduce the probability of classifying a pixel into two categories at the same time. Since different hematoma volumes and locations have different treatments. We also measure hematoma volume, estimate centroid deviation, and compare with clinical methods. Finally, we plan the puncture path and conduct clinical validation. We collected a total of 351 cases, and the test set contained 103 cases. For intraparenchymal hematomas, the accuracy can reach 96 % when the proposed method is applied for path planning. For intraventricular hematomas, the proposed model's segmentation efficiency and centroid prediction are superior to other comparable models. Experimental results and clinical practice show that the proposed model has potential for clinical application. In addition, our proposed method has no complicated modules and improves efficiency, with generalization ability.

Injury of the optic radiation in patients with mild TBI: A DTT study

Objectives

We investigated injuries of the optic radiations (ORs) in patients with mild traumatic brain injury (TBI) by using diffusion tensor tractography (DTT).

Methods

Fifty-two consecutive patients who complained of visual problems showed abnormal visual evoked potential (VEP) latency but no abnormality on conventional brain MRI after mild TBI, and fifty normal control subjects were recruited for this study. Subjects' ORs were reconstructed using DTT, and three DTT parameters (fractional anisotropy [FA], apparent diffusion coefficient [ADC], and tract volume) were measured for each OR.

Results

Mean FA value and tract volume of the OR were significantly lower in the patient group than in the control group (p < 0.05). However, there was no significant difference in the ADC values of the OR between the patient and control groups (p > 0.05). A weak negative correlation was detected between VEP latency and OR fiber number (r = 0.204, p < 0.05).

Conclusions

DTT revealed that OR injuries were not detected on the conventional brain MRI scans of patients who complained of visual problems and had abnormal VEP latency after mild TBI. Our results suggest that DTT would be a useful technique for detecting OR injury in patients with mild TBI.

Diffusion Tensor Imaging Studies on Recovery of Injured Optic Radiation: A Minireview

The optic radiation (OR) is a visual neural fiber pathway for the transfer of visual information from the lateral geniculate body of the thalamus to the primary visual cortex. To demonstrate the recovery of an OR injury, quantification and visualization of changes to the injured OR are necessary. Diffusion tensor imaging (DTI) allows determination of the state of an OR by assessing the obtained DTI parameters. In particular, diffusion tensor tractography (DTT), which is derived from DTI data, allows three-dimensional visualization of the OR. Thus, recovery of an injured OR can be demonstrated by examining changes in DTI parameters and/or configuration on follow-up DTI scans or via DTT of the injured OR. Herein, we review nine DTI-based studies that demonstrated recovery of OR injuries. The results reported in these studies suggest that an OR injury has a potential for recovery. Moreover, the results of these studies can form a basis for elucidating the recovery mechanisms of injured OR. These studies have suggested two recovery mechanisms for OR injury: recovery via the original OR pathway or via the transcallosal fibers of the corpus callosum. However, only nine studies on this topic have been conducted to date and six of those nine studies were case reports. Therefore, further studies involving larger numbers of subjects and reporting precise evaluations of changes in OR injury during recovery are warranted.

Optic radiation injury in patients with aneurismal subarachnoid hemorrhage: A preliminary diffusion tensor imaging report

Visual field defect is one of the various clinical manifestations in patients with subarachnoid hemorrhage (SAH). Little is known about the pathogenic mechanism of visual field defect in SAH. In the current study, we investigated the diffusion tensor imaging (DTI) finding of the optic radiation in patients with SAH following rupture of a cerebral artery aneurysm. We recruited 21 patients with aneurismal SAH (12 males, 9 females, mean age, 52.67 years; range, 41–68 years) who showed no definite lesion along the visual pathway. Twenty-one age-and sex-matched normal control subjects were also recruited. DTI data were acquired at an average of 5.9 weeks (range: 3–12 weeks) after onset and reconstruction of the optic radiation was performed using DTI-Studio software. The fractional anisotropy value, apparent diffusion coefficient value, and fiber number of the optic radiation were measured. The fractional anisotropy value of the optic radiation was significantly decreased, and the apparent diffusion coefficient value was significantly increased, in patients with aneurismal SAH than in normal control subjects. However, there was no significant difference in the fiber number of the optic radiation between patients with aneurismal SAH and normal control subjects. The decrement of fractional anisotropy value and increment of apparent diffusion coefficient value of the optic radiation in patients with aneurismal SAH suggest optic radiation injury. Therefore, we recommend a thorough evaluation for optic radiation injury in patient with aneurismal SAH.

Injury of optic radiation and visual field defect in a patient with aneurysmal subarachnoid hemorrhage: A case report

RATIONALE

Little is known about optic radiation (OR) injury following aneurysmal subarachnoid hemorrhage (SAH). In the current study, we report on a patient who showed a visual field defect and injury of the OR following aneurysmal SAH, using diffusion tensor tractography (DTT).

PATIENT CONCERNS

At 4 weeks from onset, when a 62-year old female started rehabilitation, she complained of a visual field defect. Peripheral field defects were detected on both eyes using the Humphrey visual field test.

DIAGNOSES

The patient underwent aneurysm clipping for a ruptured aneurysm in the left posterior communicating artery and extraventricular drainage (the left prefrontal approach) for subarachnoid hemorrhage. She also underwent conservative management for intracerebral hemorrhage in the left internal capsule detected at 2 days after onset.

INTERVENTIONS

DTT data were acquired at 4 weeks after onset OUTCOMES:: Regarding DTT parameters, fiber numbers of both ORs of the patient were decreased over 2 standard deviations of that of 7 age- and sex-matched normal subjects normal control subjects. However, the value of fractional anisotropy was similar to that of normal control subjects. On the configuration of the OR of the patient, both ORs were thinner than those of normal control subjects.

LESSONS

Injury of the OR was demonstrated in a patient with a visual field defect following aneurysmal SAH, using DTT.

Damage to the Optic Radiation in Patients With Mild Traumatic Brain Injury

BACKGROUND

There are known limitations of conventional computed tomography and magnetic resonance imaging in detecting neural injury in patients with mild traumatic brain injury (TBI). Diffusion tensor imaging (DTI) provides a method to further assess cerebral injury in this patient population. We report 2 patients with mild TBI who showed injury of the optic radiation (OR) as demonstrated by DTI.

METHOD

Two patients who complained of visual field loss after mild TBI and 9 age-matched normal control subjects were recruited for this study. Peripheral field defects were detected with automated perimetry in both patients.

RESULTS

Regarding the configuration of OR, the total volume of OR was decreased in the right OR of both patients compared with controls; in contrast, the left ORs were divided into 2 parts in both patients. The voxel numbers of both ORs in both patients were more than 2 standard deviations lower than that of normal control subjects. The apparent diffusion coefficient value of the right OR in patient 2 was more than 2 standard deviations higher than that of normal controls.

CONCLUSIONS

We demonstrated injury of the OR using DTI in 2 patients who showed visual field defects after mild TBI.

Recovery of Visual Field Defect via Corpus Callosum in a Patient with Cerebral Infarct

Recovery mechanism of visual field defect in stroke patients has not been clearly elucidated. In this study, we report on a patient with a cerebral infarct who showed recovery of visual field defect via the corpus callosum, using diffusion tensor tractography (DTT) for optic radiation (OR). A 57-year-old male patient underwent conservative management for a cerebral infarct in the subcortical white matter of the right temporal lobe. Left homonymous hemianopsia was detected on the 2-week Humphrey visual field test. However, the patient showed improvement of hemianopsia with time; consequently, a left lower peripheral visual defect with the resolution of the upper and medial portions of the initial left hemianopia was observed on the 11-month Humphrey visual field test. Both 2-week and 11-month DTTs for the right OR showed a discontinuation between the right lateral geniculate nucleus (LGN) and the right OR. On 2-week DTT, the left OR was connected to the transcallosal fibres, and on 11-month DTT, these transcallosal fibres were elongated to the right primary visual cortex via the right posterior OR. The visual field defect in this patient appears to have recovered by the neural pathway originating from the left OR and terminating in the primary visual cortex via the transcallosal fibres and right distal OR. We believe that the results of this study may suggest one of the mechanisms for recovery of visual field defect following injury of OR in stroke patients.

Relationship between different surgical methods, hemorrhage position, hemorrhage volume, surgical timing, and treatment outcome of hypertensive intracerebral hemorrhage

BACKGROUND

The present study aimed to explore the relationship between surgical methods, hemorrhage position, hemorrhage volume, surgical timing and treatment outcome of hypertensive intracerebral hemorrhage (HICH).

METHODS

A total of 1 310 patients, who had been admitted to six hospitals from January 2004 to January 2008, were divided into six groups according to different surgical methods: craniotomy through bone flap (group A), craniotomy through a small bone window (group B), stereotactic drilling drainage (group C1 and group C2), neuron-endoscopy operation (group D) and external ventricular drainage (group E) in consideration of hemorrhage position, hemorrhage volume and clinical practice. A retrospective analysis was made of surgical timing and curative effect of the surgical methods.

RESULTS

The effectiveness rate of the methods was 74.12% for 1 310 patients after one-month follow-up. In this series, the disability rate was 44.82% 3-6 months after the operation. Among the 1 310 patients, 241 (18.40%) patients died after the operation. If hematoma volume was >80 mL and the operation was performed within 3 hours, the mortality rate of group A was significantly lower than that of groups B, C, D, and E (P<0.05). If hematoma volume was 50-80 mL and the operation was performed within 6-12 hours, the mortality rate of groups B and D was lower than that of groups A, C and E (P<0.05). If hematoma volume was 20-50 mL and the operation was performed within 6-24 hours, the mortality rate of group C was lower than that of groups A, B and D (P<0.05).

CONCLUSIONS

Craniotomy through a bone flap is suitable for patients with a large hematoma and hernia of the brain. Stereotactic drilling drainage is suggested for patients with hematoma volume less than 80 mL. The curative effect of HICH individualized treatment would be improved via the suitable selection of operation time and surgical method according to the position and volume of hemorrhage.

Injury of the cingulum in patients with putaminal hemorrhage: a diffusion tensor tractography study

Objectives: Little is known about the pathophysiological mechanisms of cognitive impairment in patients with putaminal hemorrhage (PH). Using diffusion tensor tractography, we investigated injury of the cingulum in patients with PH.

Methods: We recruited 63 patients with PH, who were classified according to three groups, based on integrity of the cingulum to the lower portion of the genu of the corpus callosum: group A; preserved integrity, group B; discontinuation of integrity in the affected hemisphere, and group C; discontinuation of integrity in both hemispheres.

Results: Thirty four patients (54.0%) belonged to group A, 16 patients (25.4%) to group B, and the remaining 13 patients (20.6%) to group C. Regarding the Mini-Mental State Examination, significant differences were observed between group A and group C, and between group B and group C without significant difference between group A and group B (p < 0.05). In terms of the volume of hematoma, significant differences were observed among the three groups (p < 0.05). Regarding the most anterior point of the hematoma, significant differences were observed between group A and groups B and C (p < 0.05); in contrast, regarding the most point of hematoma, significant differences were observed between group C and groups A and B, respectively (p < 0.05).

Conclusion: We found that the anterior cingulum is vulnerable to PH. Therefore, our results suggest the necessity for evaluation of the cingulum in patients with PH particularly if the hematoma is large or close to the anterior margin or midline of the brain.

Quantitative volumetric analysis of the optic radiation in the normal human brain using diffusion tensor magnetic resonance imaging-based tractography

To attain the volumetric information of the optic radiation in normal human brains, we performed diffusion tensor imaging examination in 13 healthy volunteers. Simultaneously, we used a brain normalization method to reduce individual brain variation and increase the accuracy of volumetric information analysis. In addition, tractography-based group mapping method was also used to investigate the probability and distribution of the optic radiation pathways. Our results showed that the measured optic radiation fiber tract volume was a range of about 0.16% and that the fractional anisotropy value was about 0.53. Moreover, the optic radiation probability fiber pathway that was determined with diffusion tensor tractography-based group mapping was able to detect the location relatively accurately. We believe that our methods and results are helpful in the study of optic radiation fiber tract information.