3-dimensional Constructive Interference Research Articles

Adult Moyamoya Disease and Moyamoya Syndrome: What Is New?

Recent advances are in the genetics, diagnosis, pathophysiology, and management of moyamoya disease (MMD), and moyamoya syndrome (MMS), a term used to describe moyamoya-like vasculopathy associated with various systemic diseases or conditions. Ring finger protein (RNF213) has been reported to be a susceptibility gene not only for MMD but also for atherosclerotic intracranial arterial stenosis and ischemic stroke attributable to large artery atherosclerosis. The latest guidelines by the Research Committee on MMD of the Japanese Ministry of Health, Labor, and Welfare, removed limitations of the previous definition that required bilateral involvement of the intracranial carotid artery to make the diagnosis, given the increasing evidence of progression to bilateral involvement in unilateral MMD. 3-dimensional constructive interference in steady-state MRI is useful for the differential diagnosis of MMD from atherosclerosis. Recent advances in the pathophysiology of MMD suggest that genetic and environmental factors play important roles in vascular angiogenesis and remodeling via complex mechanisms. The latest Japanese Guidelines and American Scientific Statement described that antiplatelet therapy can be considered reasonable. Endovascular interventional stent placement fails to prevent ischemic events and does not halt MMD progression. In the Japan Adult Moyamoya trial, a randomized controlled trial for bilateral extracranial-intracranial direct bypass versus conservative therapy in patients with MMD, who had intracranial hemorrhage, recurrent bleeding, completed stroke, or crescendo transient ischemic attack was significantly fewer with direct bypass than with conservative care. This review presents updated information on genetics, diagnosis, pathophysiology, and treatment of adult MMD and MMS. Despite recent advances, many mysteries still exist in the etiologies of moyamoya vasculopathy. The diagnostic criteria and treatment guidelines have been updated but not yet been globally established. Ongoing and future studies investigating underlying pathophysiological mechanisms of MMD and MMS may clarify potentially effective medical, surgical, or endovascular treatments.

57-Year-Old Man With Headache, Vomiting, and Gait Instability

57-Year-Old Man With Headache, Vomiting, and Gait Instability

Role of Fused Three-Dimensional Time-of-Flight Magnetic Resonance Angiography and 3-Dimensional T2-Weighted Imaging Sequences in Neurovascular Compression

To evaluate role of fused 3-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) and 3-dimensional constructive interference in steady state (3D-CISS) in neurovascular compression in trigeminal neuralgia (TN) and hemifacial spasm (HFS). A prospective study was conducted on 30 patients (mean age 47.20 ± 11.69 years), 17(56.7%) male and 13 (43.3%) female, with TN and HFS. 3D-TOF-MRA and 3D-CISS sequences of the cerebellopontine angle were performed, as well as postprocessing with fusion of the images. Two independent readers assessed the degree of neurovascular conflict. The images were evaluated for site, signal, and degree of nerve compression and the offending vessel. The kappa test for interobserver agreement was done. The interobserver agreement of both readers was excellent for degree of compression (k= 0.70, 95% confidence interval [CI] 0.49-0.92, r= 0.856, P= 0.001), excellent for the side affected (k= 1.0, 95% CI= 1.0-1.0, r= 1.000, P= 0.001), excellent for the offending vessel (k= 0.85, 95% CI= 0.66-1.0, P= < 0.001), and excellent for the position of the offending vessel (k= 0.685, 95% CI= 0.489-0.882, r= 0.863, P ≤ 0.001). There was no significant correlation between the degree of compression and signal intensity. Fused 3D-TOF-MRA and 3D-CISS images are a reliable, noninvasive tool for the evaluation of offending vessel and degree of affection in patients with neurovascular compression. MRA-CISS can be used for evaluation and treatment planning of neurovascular compression in TN and HFS.

Morphometric analysis of facial and cochlear nerves in normal-hearing ears using 3D-CISS

PurposeThe aim of the current study was to establish a normative data set for the morphometric parameters of the facial nevre (FN) and cochlear nevre (CN) according to age and sex in the adult population, using 3-dimensional constructive interference in steady state (3D-CISS) sequence on magnetic resonance imaging. MethodsWe retrospectively analyzed 157 ears of 102 adults with no hearing impairment, facial palsy or Ménière's disease. The vertical (VD) and horizontal (HD) diameters as well as cross-sectional areas (CSAs) of the FNs and CNs were measured on the parasagittal oblique image created using the axial 3D-CISS sections passing through the internal acoustic canal. We related the measurement results with side, sex and age. ResultsThe mean VD, HD and CSA of the FNs were 1.09 ± 0.18 mm, 0.84 ± 0.17 mm, and 0.75 ± 0.27 mm2, respectively, whereas those of the CNs were 1.34 ± 0.17 mm, 1 ± 0.15 mm and 1.06 ± 0.3 mm2, respectively. There was no statistically significant difference between the morphometric parameters of both the nerves according to side or sex (P > 0.05). However, except for the CSA of the FNs among males, we found a statistically significant decrease in all the morphometric parameters of both the nerves with ageing (P < 0.05). ConclusionThe normative morphometric data obtained in this study can be beneficial in clinical applications for sensorineural hearing loss, facial palsy and Ménière's disease.

Stenosis Severity-Dependent Shrinkage of Posterior Cerebral Artery in Moyamoya Disease

The involved carotid forks in moyamoya disease (MMD) will show decreases in both luminal caliber and outer diameter. The present study aimed to clarify the changes in the outer diameter associated with luminal stenosis/occlusion of the posterior cerebral artery (PCA) in patients with MMD. The present study included 24 pediatric and 48 adult patients with MMD and 17 healthy adult controls. Using magnetic resonance angiography, the degree of PCA involvement was classified into 3 grades: grade 0, normal; grade 1, stenotic; and grade 2, occluded. Using 3-dimensional constructive interference in steady state, the outer diameters were quantified in the P2 segment. All the patients were followed up to identify the disease progression in the PCA. The outer diameter of the P2 segment significantly decreased in a stepwise fashion in parallel with the severity of the luminal stenosis. In pediatric patients, the outer diameters of the P2 segments were 2.0 ± 0.26 mm, 1.5 ± 0.42 mm, and 0.87 ± 0.15 mm in those with grade 0, 1, and 2, respectively (P < 0.001). In adult patients, the outer diameters of the P2 segments were 2.0 ± 0.34 mm, 1.5 ± 0.34 mm, and 1.1 ± 0.17 mm in those with grade 0, 1, and 2, respectively (P < 0.001). We found no significant difference between grade 0 PCA of the adult patients and the PCA of the healthy controls (P= 0.92). Disease progression led to further arterial shrinkage of the P2 segment (n= 4). The results of our study have shown that the involved PCA demonstrates, not only luminal stenosis, but also arterial shrinkage in MMD. This finding strongly suggests that the underlying mechanism in the development of MMD is common in both the carotid fork and PCA.

Is Quasi-moyamoya Disease a Uniform Disease Entity? A Three-Dimensional Constructive Interference in Steady State Imaging Study

Quasi-moyamoya disease (MMD) or moyamoya syndrome is based on various underlying diseases and radiologically simulates MMD, but its disease entity is still unclear. Recent studies have proven specific shrinkage of the involved arteries in MMD. Using 3-dimensional constructive interference in steady state (3D-CISS), therefore, this study aimed to analyze the outer diameter of the involved arteries in quasi-MMD. This study included 9 patients with quasi-MMD (unilateral type, n = 2; bilateral type, n = 7). Using 3D-CISS, the outer diameter was quantified in the internal carotid artery distal to the posterior communicating artery (C1), the horizontal portion of the middle and anterior cerebral arteries (M1 and A1, respectively), and the basilar artery. Control values were obtained from 17 healthy subjects. In 7 of 9 patients, the outer diameters of C1, M1, and A1 were significantly smaller than those of the controls. On the other hand, the values were normal in other 2 patients. There was no significant difference in the underlying disorders between the 2 groups. All 3 pediatric patients are categorized into the arterial shrinkage group, but 2 of 6 adult patients were not. These findings strongly suggest that quasi-MMD is not a uniform disease entity and includes at least 2 pathophysiologically different groups: the arterial shrinkage group and the nonarterial shrinkage group. A certain subgroup of MMD patients may be misdiagnosed as quasi-MMD because of the patients' comorbid disorders and mixed up with the patients who present angiographic findings similar to MMD in spite of the lack of arterial shrinkage.

In Situ, Noninvasive, T2*-Weighted MRI-Derived Parameters Predict Ex Vivo Structural Properties of an Anterior Cruciate Ligament Reconstruction or Bioenhanced Primary Repair in a Porcine Model

Background: Magnetic resonance imaging (MRI) is a noninvasive technology that can quantitatively assess anterior cruciate ligament (ACL) graft size and signal intensity. However, how those properties relate to reconstructed or repaired ligament strength during the healing process is yet unknown. Hypothesis: Magnetic resonance imaging–derived measures of graft volume and signal intensity are significant predictors of the structural properties of an ACL or ACL graft after 15 weeks and 52 weeks of healing. Study Design: Controlled laboratory study. Methods: The current data were gathered from 2 experiments evaluating ACL reconstruction and repair techniques. In the first experiment, pigs underwent unilateral ACL transection and received (1) ACL reconstruction, (2) ACL reconstruction with collagen-platelet composite (CPC), or (3) no treatment. The surgical legs were harvested after 15 weeks of healing. In the second experiment, pigs underwent ACL transection and received (1) ACL reconstruction, (2) ACL reconstruction with CPC, (3) bioenhanced ACL primary repair with CPC, or (4) no treatment. The surgical legs were harvested after 52 weeks. The harvested knees were imaged using a T2*-weighted 3-dimensional constructive interference in steady state (CISS) sequence. Each ligament was segmented from the scans, and the intra-articular volume and the median grayscale values were determined. Mechanical testing was performed to establish the ligament structural properties. Results: Volume significantly predicted the structural properties (maximum load, yield load, and linear stiffness) of the ligaments and grafts (R2 = 0.56, 0.56, and 0.49, respectively; P ≤ .001). Likewise, the median grayscale values (ie, signal intensity) significantly predicted the structural properties of the ligaments and grafts (R2 = 0.42, 0.37, and 0.40, respectively; P < .001). The combination of these 2 parameters in a multiple regression model improved the predictions (R2 = 0.73, 0.72, and 0.68, respectively; P ≤ .001). Conclusion: Volume and grayscale values from high-resolution T2*-weighted MRI scans are predictive of structural properties of the healing ligament or graft in a porcine model. Clinical Relevance: This study provides a critical step in the development of a noninvasive method to predict the structural properties of the healing ACL graft or repair. This technique may prove beneficial as a surrogate outcome measure in preclinical animal and clinical studies.

Establishing Normal Diameter Range of the Cochlear and Facial Nerves with 3D-CISS at 3T

We explored normal diameter values of the cochlear (CN) and facial (FN) nerves on 3-dimensional constructive interference in steady state (3D-CISS) using a 3-tesla magnetic resonance (MR) imaging scanner. A total of 142 patients underwent MR imaging of the inner ear at 3T. We retrospectively analyzed data from 172 ears. All ears had normal hearing and no history of ipsilateral facial palsy. Parasagittal images of 0.5-mm thickness perpendicular to the internal auditory canal were reconstructed from 0.4-mm thick axial 3D-CISS images for all ears. Two independent radiologists measured the long diameter (LD), short diameter (SD), and cross-sectional area (CSA) of each CN and FN. For each measurement, we calculated the mean value from the 2 observers and evaluated interobserver agreement. We also evaluated the correlation between nerve diameter and sex and age. Both observers could perform measurements in 157 CN from 172 ears (91%) and 165 FN from 172 ears (96%). For the CN, the mean LD was 1.35±0.16 mm, the mean SD was 0.99±0.18 mm, and the mean CSA was 1.07±0.30 mm2; for the FN, the mean values were 1.18±0.17 mm (LD), 0.87±0.16 mm (SD), and 0.83±0.27 mm2 (CSA). Interobserver reliability was good for each measurement (r=0.569 to 0.691, P<0.01). The diameters of the 2 nerves tended to be larger in men, but only the CSA of the FN was significantly larger in men (P<0.05). Age did not affect nerve diameter. We present normal values of CN and FN diameters on 3D-CISS at 3T. Our results warrant further study to clarify the pathophysiological state of the CN or FN using 3D-CISS.

A Case of Cochlear Nerve Deficiency Without Profound Sensorineural Hearing Loss

To describe a case of cochlear nerve deficiency (CND) with unique otologic findings. A 6-year-old girl. Magnetic resonance imaging, pure tone audiometry, distortion product otoacoustic emissions, and auditory brainstem response. The patient showed moderate sensorineural hearing impairment limited to high frequency in the right ear on pure tone audiometry. The auditory brainstem response was absent on the right; however, distortion product otoacoustic emissions were detected on both sides. The right cochlear nerve at the level of the fundus was absent on 3-dimensional constructive interference in steady state magnetic resonance imaging. Most cases of CND show deafness or profound hearing loss, but the patient in this case had only moderate hearing loss. This finding provides evidence that auditory thresholds are variable in patients with CND. Therefore, careful evaluation is needed in diagnosis of patients with hearing loss.

Study of the Anatomical Variations of Vertebral Artery in C2 Vertebra With Magnetic Resonance Imaging and Its Application in the C1–C2 Transarticular Screw Fixation

Use of magnetic resonance imaging (MRI) with Constructive Interference in Steady State (CISS) sequence and isometric voxels to demonstrate the anatomic variations of vertebral artery in C2 vertebra. To determine the transarticular screw trajectory on CISS MRI and to identify patients with anatomic variations of vertebral artery in C2 vertebra. Atlantoaxial transarticular screw fixation has been reported to be biomechanically superior to other posterior techniques for atlantoaxial arthrodesis. Vertebral artery injury can be associated with catastrophic sequelae. Anatomic variation of vertebral artery is well recognized and computed tomography scan is the traditional preoperative assessment. However, no report has evaluated the use of MRI in preoperative assessment for the screw trajectories and the anatomic variation of vertebral artery. The 3-dimensional (3D) CISS MRI with isometric voxels was performed in 30 local Chinese patients. The 3D reconstruction images were created to determine the proposed screw trajectories and their relationship with the vertebral arteries. In 12 patients (40%), the vertebral arteries were lying within the screw trajectories prohibiting transarticular screw fixation on at least one side. Bilateral variations with high risk of vertebral artery injuries were found in 6 patients. The remaining 6 patients had unilateral variations prohibiting the insertion of transarticular screws on one side. The 3D CISS MRI with isometric voxels is a safe and simple imaging technique to outline the vertebral arteries in C2. Reconstruction images are easily created and undistorted. It is one of the useful imaging in preoperative planning of transarticular screw fixation and determination of anatomy of vertebral artery.

A multiarray electrode mapping method for percutaneous thermocoagulation as treatment of trigeminal neuralgia. Technical note on a series of 178 consecutive procedures

Background We describe our method and mapping technique of the trigeminal nerve using a quadripolar electrode to minimize morbidity of percutaneous thermocoagulation as treatment of trigeminal neuralgia. Method Of 381 patients selected for postgasserian thermocoagulation, 178 consecutive procedures were carried out using, in most cases, our painless and ambulatory method and technique. All patients were preoperatively subjected to 3-dimensional constructive interference in steady-state magnetic resonance and magnetic resonance angiography. Transgasserian introduction of our quadripolar multiarray electrode under constant fluoroscopic monitoring is used with systematic recording of radiologic angles at, in front of, and behind the clivus profile, always below the selar floor. The individual's somatotopic map based on the verbal responses of 34 facial subsegments in lieu of the usual 3 is carefully established. Lesions are aimed at the trigger of pain and restricted to fibers with the lowest thresholds. Maximal lesions are one third the size used in conventional thermocoagulation. Lesions attempt to avoid damage to the first division, uninvolved fibers, and the motor division. Results Pre- and postoperatory thresholds demonstrate that trigger-aimed small lesions do not extend to unwanted subsegments. The described technique can minimize unnecessary complications from percutaneous thermocoagulation.

Visualization of the IXth to XIIth cranial nerves using 3-dimensional constructive interference in steady state, 3-dimensional magnetization-prepared rapid gradient echo and T2-weighted 2-dimensional turbo spin echo magnetic resonance imaging sequences.

The purpose of this study was to evaluate the visibility of the IXth to XIIth cranial nerves using different magnetic resonance sequences. Thirty healthy volunteers underwent magnetic resonance imaging at 1.5 T using 3-dimensional constructive interference in steady state (CISS) sequence (TR = 17 ms, TE = 8.08 ms, alpha = 70 degrees), 3-dimensional magnetization-prepared rapid gradient echo (MP-RAGE) sequence (TR = 11.08 ms, TE = 4.3 ms, alpha = 15 degrees), and T2-weighted (w) 2-dimensional turbo spin echo (TSE) sequence (TR = 4000 ms, TE = 102 ms, alpha = 180 degrees, slice thickness = 2 mm). Visibility of the IXth to XIIth cranial nerves in each sequence was evaluated by consensus of 2 radiologists using an evaluation scale from 1 (excellently visible) to 5 (not visible). A correlation with anatomic specimens was made. The 3-dimensional CISS sequence provides best resolution of the IXth to XIIth cranial nerves and their relation to surrounding structures. Additional information is given by the 3-dimensional MP-RAGE when nerves are surrounded by soft tissues. Using the T2w 2-dimensional TSE sequence, even whole nerves cannot be visualized due to intersection gap and partial volume effects. However, even in 3-dimensional high-resolution sequences, segments of nerves are not always visualized. A combination of 3-dimensional CISS and 3-dimensional MP-RAGE proved to be useful to visualize the IXth to XIIth cranial nerves, whereas the 2-dimensional technique failed. Further investigations using 3-dimensional MP-RAGE with contrast medium should be performed in the case of abnormality.