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

Surgical treatment of cerebellar pontine angle lipoma combined with trigeminal neuralgia: A case report

RATIONALE

Cerebellar pontine angle lipomas with trigeminal neuralgia are rare. The treatment choice is influenced by whether the pain is caused by the lipoma or the compression of blood vessels. Herein, we aimed to report a case of the disease and provide a reference for its treatment.

PATIENT CONCERNS

The patient was a 54-year-old female who presented with a 20-year history of left-sided facial pain. Her pain had gradually worsened over time and oral medications became progressively less effective.

DIAGNOSES

Brain magnetic resonance imaging detected a left cerebellar horn lesion, which was deemed a lipoma. Three-dimensional time-of-flight magnetic resonance angiography revealed a superior cerebellar artery adjacent to the trigeminal nerve root. Trigeminal nerve roots may have been compressed by lipomas and blood vessels.

INTERVENTIONS

The patient underwent a microvascular decompression of the trigeminal nerve. Part of the lipoma was removed, and the trigeminal nerve was isolated from the blood vessels and tumor.

OUTCOMES

Postoperative pathology confirmed a lipoma. Neuralgia was completely relieved postoperatively, and no new neurological disorder was detected during the 6-month follow-up.

LESSONS

Surgery is recommended for patients with cerebellar pontine angle lipomas combined with trigeminal neuralgia when conservative treatment fails. Detailed preoperative imaging is crucial to identify lipomas and trigeminal root compression by the responsible artery. Complete decompression of the trigeminal nerve root is necessary for complete pain relief.

Super-resolution Deep Learning Reconstruction for 3D Brain MR Imaging: Improvement of Cranial Nerve Depiction and Interobserver Agreement in Evaluations of Neurovascular Conflict

RATIONALE AND OBJECTIVES

To determine if super-resolution deep learning reconstruction (SR-DLR) improves the depiction of cranial nerves and interobserver agreement when assessing neurovascular conflict in 3D fast asymmetric spin echo (3D FASE) brain MR images, as compared to deep learning reconstruction (DLR).

MATERIALS AND METHODS

This retrospective study involved reconstructing 3D FASE MR images of the brain for 37 patients using SR-DLR and DLR. Three blinded readers conducted qualitative image analyses, evaluating the degree of neurovascular conflict, structure depiction, sharpness, noise, and diagnostic acceptability. Quantitative analyses included measuring edge rise distance (ERD), edge rise slope (ERS), and full width at half maximum (FWHM) using the signal intensity profile along a linear region of interest across the center of the basilar artery.

RESULTS

Interobserver agreement on the degree of neurovascular conflict of the facial nerve was generally higher with SR-DLR (0.429-0.923) compared to DLR (0.175-0.689). SR-DLR exhibited increased subjective image noise compared to DLR (p ≥ 0.008). However, all three readers found SR-DLR significantly superior in terms of sharpness (p < 0.001); cranial nerve depiction, particularly of facial and acoustic nerves, as well as the osseous spiral lamina (p < 0.001); and diagnostic acceptability (p ≤ 0.002). The FWHM (mm)/ERD (mm)/ERS (mm-1) for SR-DLR and DLR was 3.1-4.3/0.9-1.1/8795.5-10,703.5 and 3.3-4.8/1.4-2.1/5157.9-7705.8, respectively, with SR-DLR's image sharpness being significantly superior (p ≤ 0.001).

CONCLUSION

SR-DLR enhances image sharpness, leading to improved cranial nerve depiction and a tendency for greater interobserver agreement regarding facial nerve neurovascular conflict.

The progress in epidemiological, diagnosis and treatment of primary hemifacial spasm

Hemifacial Spasm is a neurological disorder characterized by persistent and rhythmic spasms of the facial muscles, significantly affecting the patient's quality of life. This condition can be classified into primary and secondary types; this article focuses on the characteristics of primary hemifacial spasm. Epidemiological studies indicate that the condition is more common in women, older adults, and individuals with posterior fossa stenosis or uneven blood flow dynamics, and is associated with gene expression related to demyelinating lesions. In terms of diagnosis, magnetic resonance imaging can show the location of arterial or venous compression on the facial nerve on a macroscopic level and reveal white matter lesions on a microscopic level. Additionally, optimized electrophysiological techniques can determine the type of neural excitation disorder from both central and peripheral perspectives, thereby improving detection rates. There are numerous treatment options available. Although early oral medications may have limited effectiveness, botulinum toxin injections can provide temporary relief. Future considerations include balancing injection costs with long-term efficacy. Microvascular decompression remains the preferred treatment approach and can be further optimized with endoscopic techniques. For refractory cases, alternative therapies such as facial nerve massage, radiofrequency techniques, rhizotomy, or acupuncture may be considered.

Preoperative Evaluation of Neurovascular Relationship in Primary Trigeminal Neuralgia(PTN) by Magnetic Resonance Virtual Endoscopy(MRVE) Combined with 3D-FIESTA-c and 3D-TOF-MRA

Objective

This study aims to evaluate the effectiveness of Magnetic Resonance Virtual Endoscopy combined with 3D-FIESTA-c and 3D-TOF-MRA in preoperative assessment of MVD for PTN, with a focus on accurately detecting neuromuscular contact.

Methods

We retrospectively analyzed clinical and imaging data from 240 patients with unilateral primary trigeminal neuralgia undergoing MVD surgery between April 2016 and July 2023. Preoperative scans with 3D-FIESTA-c and 3D-TOF-MRA were performed, and MRVE images were obtained to analyze the relationship between the trigeminal nerve and adjacent vessels. Using the findings during microvascular decompression (MVD) surgery as the gold standard, the diagnostic results of 3D-TOF-MRA + 3D-FIESTA-c were considered as group I, while the combined use of MRVE, 3D-TOF-MRA + 3D-FIESTA-c was considered as group II.

Results

In 240 cases, group I had a positive rate of 96.25% and an accuracy rate of 86.25% for identifying responsible blood vessels, while group II had a positive rate of 98.3% and an accuracy rate of 94.17%. There were no statistically significant differences in positive rates between group I and group II, group I and MVD, or group II and MVD (P > 0.05). However, there were statistically significant differences in accuracy rates (P < 0.05). The accuracy for single and multiple arteries with group I was 99.38% and 80.0%, respectively, while with group II, it was 100% and 95.0%. No statistically significant difference was found in accuracy for single or multiple arteries (P>0.05). The accuracy of evaluating responsibility veins with or without other vessels was 52.73% and 80.0%, respectively, with a statistically significant difference (P<0.05).

Conclusion

MRVE combined with 3D-TOF-MRA + 3D-FIESTA-c significantly improves the accuracy of identifying responsibility vessels, especially veins, in preoperative assessment for MVD. This has important clinical implications for preoperative decision-making and surgical planning.

Awake neurosurgery: Advancements in microvascular decompression for trigeminal neuralgia

Background

The treatment landscape for trigeminal neuralgia (TN) involves various surgical interventions, among which microvascular decompression (MVD) stands out as highly effective. While MVD offers significant benefits, its success relies on precise surgical techniques and patient selection. In addition, the emergence of awake surgery techniques presents new opportunities to improve outcomes and minimize complications associated with MVD for TN.

Methods

A thorough review of the literature was conducted to explore the effectiveness and challenges of MVD for TN, as well as the impact of awake surgery on its outcomes. PubMed and Medline databases were searched from inception to March 2024 using specific keywords "Awake Neurosurgery," "Microvascular Decompression," AND "Trigeminal Neuralgia." Studies reporting original research on human subjects or preclinical investigations were included in the study.

Results

This review highlighted that MVD emerges as a highly effective treatment for TN, offering long-term pain relief with relatively low rates of recurrence and complications. Awake surgery techniques, including awake craniotomy, have revolutionized the approach to MVD, providing benefits such as reduced postoperative monitoring, shorter hospital stays, and improved neurological outcomes. Furthermore, awake MVD procedures offer opportunities for precise mapping and preservation of critical brain functions, enhancing surgical precision and patient outcomes.

Conclusion

The integration of awake surgery techniques, particularly awake MVD, represents a significant advancement in the treatment of TN. Future research should focus on refining awake surgery techniques and exploring new approaches to optimize outcomes in MVD for TN.

The Visualization of Intraneural Venous Compression in Trigeminal Neuralgia by Using Advanced Three-Dimensional Computer Graphics: An Illustrative Case Report

Trigeminal neuralgia (TN) caused by venous compression presents challenges in surgical management, unlike the arterial type. Preoperative diagnostic certainty regarding venous etiology and anatomical relationships is crucial for surgical success. We discuss a case of TN caused by a vein passing through the nerve that was challenging to visualize on conventional MRI and was treated successfully by leveraging information from modern surgical simulation technology with 3D computer graphics. We recognized a potentially troublesome anatomical feature in advance and mitigated the risk by identifying a collateral drainage route for the causative vein, making it feasible to be sacrificed while ensuring treatment efficacy.

Usefulness of silent magnetic resonance angiography (MRA) for the diagnosis of atherosclerosis of the internal carotid artery siphon in comparison with time-of-flight MRA

Background and purpose

Flow visualization in 3D time-of-flight MRA (3D-TOF MRA) may be limited for internal carotid artery siphon owing to turbulent artifact. The purpose of this study was to compare the usefulness of Silent MRA and 3D-TOF MRA to assess atherosclerosis of the internal carotid artery siphon.

Material and methods

A total of 106 patients with suspected cerebrovascular disease were included. All patients were scanned with Silent MRA and 3D-TOF MRA sequences and also underwent DSA examination. Two observers independently assessed the TOF MRA and Silent MRA images of atherosclerosis of the internal carotid artery siphon. The diagnostic efficacy of two MRA methods in evaluating atherosclerosis of the carotid siphon was performed by using receiver operating characteristic (ROC) curve analysis. Interobserver reliability was also assessed using weighted kappa statistics.

Results

Image of Silent MRA sequence had higher subjective evaluation scores and significantly high CNR between the carotid siphon and the background tissues than the image of 3D-TOF MRA sequence (P < 0.05). The AUC was 0.928 (95% CI 0.909–0.986) for Silent MRA, which was significantly higher than that of 3D-TOF MRA (0.671, 95% CI 0.610–0.801, P < 0.05). Silent MRA had high sensitivity, specificity and accuracy than 3D-TOF MRA for visualization of the carotid siphon.

Conclusions

Silent MRA as a new angiographic modality is superior to 3D-TOF MRA for visualization of the carotid siphon, and maybe an alternative to 3D-TOF MRA in the diagnosis of atherosclerosis of the carotid siphon.

Predictability of Fused 3D-T2-SPACE and 3D-TOF-MRA Images in Identifying Conflict in Trigeminal Neuralgia

Purpose

To evaluate the efficacy of fused three-dimensional T2 sampling perfection with application-optimized contrasts using different flip-angle evolutions (3D-SPACE) and three-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) sequences for detecting neurovascular compression (NVC) in patients presenting with trigeminal neuralgia (TN).

Methods

A prospective study was carried in 33 consecutive patients (m/f: 17/16; mean age, 56.3 ± 10.4 years) with unilateral TN confirmed NVC and consensus by two experienced radiologists on fused 3D-SPACE and 3D-TOF-MRA sequences of 3-tesla (3-T) MRI. All patients underwent microvascular decompression (MVD), using photos and video in surgery as documents compared with MRI. Both the MRI and MVD were reported for three grades (contact, compression, distortion), vessel types (artery or vein), identification of offending vessel, site (juxtapontine, cisternal, and juxtapetrous), and location (cranial, caudal, medial, lateral). Agreement between preoperative MRI visualization and surgical findings was assessed using the kappa (K) statistic.

Results

The k-values for the agreement were excellent for the grade of NVC (k=0.82), vessel types (k=0.78), and location of conflict (k=0.74), and good for identification of the offending vessel (0.65) and the site-affected vessel (k=0.69).

Conclusion

The fused D3-SPACE and 3D-TOF-MRA images are highly effective tools for the evaluation and treatment planning of NVC in TN patients.

The evaluation of patient demographics, etiologies and apraclonidine test results in adult Horner's syndrome

PURPOSE

We aimed to demonstrate the patient demographics, etiologies and apraclonidine test results in adult Horner's syndrome.

METHODS

This retrospective study was performed by the analysis of medical data of patients who were given 0.5% apraclonidine test. Patients' past medical history, demographic data, etiologies, accompanying neurological findings and pharmacological test results were assessed.

RESULTS

Forty patients (21 females and 19 males) with a mean age of 50.3 ± 11.6 years were evaluated. Apraclonidine 0.5% test was positive in 37 patients (92.5%). An etiology could be identified in 20 patients (central [9 patients, 45%], preganglionic [9 patients, 45%] and postganglionic [2 patients, 10%]). Neurological findings accompanying Horner's syndrome were present in 8 patients.

CONCLUSION

Despite detailed investigations, in a significant number of patients with Horner's syndrome an underlying cause may not be detected. Among the identifiable lesions, central and preganglionic involvements are still the first leading causes of Horner's syndrome. In addition, apraclonidine test may not be positive in all patients and a negative response does not exclude Horner's syndrome.

Vestibular paroxysmia: Clinical features and imaging findings; a literature review

According to the definition of neurovascular compression syndromes (NVCS), a vascular structure in direct contact with a cranial nerve is causing mechanical irritation of the neural tissue producing correlating symptoms. Vestibular paroxysmia is an example of a neurovascular compression which is caused by neurovascular contact between the eighth cranial nerve and a vessel. It is crucial to understand the unique anatomy of the vestibulocochlear nerve in order to study the syndrome which is the result of its compression. More specifically, the long transitional zone between central and peripheral myelin plays a central role in clinical significance, as the transitional zone is the structure most prone to mechanical injury. Imaging techniques of the eighth cranial nerve and the surrounding structures are substantial for the demonstration of clinically significant cases and potential surgical decompression. The goal of the current review is to present and study the existing literature on vestibular paroxysmia and to search for the most appropriate imaging technique for the syndrome. An extensive literature search of PubMed database was performed, and the studies were ranked based on evidence-based criteria, followed by descriptive statistics of the data. The present analysis indicates that 3D CISS MRI sequence is superior to any other sequence, in the most studies reviewed, regarding the imaging of neurovascular compression of the eighth cranial nerve.

Recent Advances of Magnetic Resonance Neuroimaging in Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a disease of unclear pathogenesis. It has a low incidence and is not fatal, but it can cause afflicted patients' depression or suicide. In the past, neurovascular compression was considered to be the main cause of TN, but recent studies have found that neurovascular contact is also common in asymptomatic patients and the asymptomatic side in symptomatic patients. This indicates that the neurovascular contact is not, or is only to a lesser extent, a factor in the development of TN. Thus, the study of the peripheral branches of the trigeminal nerve is necessary to understand the etiology of TN. With the development of imaging technology and the emergence of various imaging modalities, it is possible to study the etiology of TN and the pathological changes of related structures by magnetic resonance neuroimaging. This article reviews the recent advances in magnetic resonance neuroimaging of the trigeminal nerve.

Gravity determines the direction of nerve roots sedimentation in the lumbar spinal canal

Objectives

To investigate the role of gravity in the sedimentation of lumbar spine nerve roots using magnetic resonance (MR) imaging of various body positions.

Methods

A total of 56 patients, who suffered from back pain and underwent conventional supine lumbar spine MR imaging, were selected from sanmen hospital database. All the patients were called back to our hospital to perform MR imaging in prone position or lateral position. Furthermore, the sedimentation sign (SedSign) was determined based on the suspension of the nerve roots in the dural sac on cross-sectional MR images, and 31 cases were rated as positive and another 25 cases were negative.

Results

The mean age of negative SedSign group was significantly younger than that of positive SedSign group (51.7 ± 8.7 vs 68.4 ± 10.5, P < 0.05). The constitutions of clinical diagnosis were significantly different between patients with a positive SedSign and those with a negative SedSign (P < 0.001). Overall, nerve roots of the vast majority of patients (48/56, 85.7%) subsided to the ventral side of the dural sac on the prone MR images, although that of 8 (14.3%) patients remain stay in the dorsal side of dural sac. Nerve roots of only one patient with negative SedSign did not settle to the ventral dural sac, while this phenomenon occurred in 7 patients in positive SedSign group (4% vs 22.6%, P < 0.001). In addition, the nerve roots of all the five patients subsided to the left side of dural sac on lateral position MR images.

Conclusions

The nerve roots sedimentation followed the direction of gravity. Positive SedSign may be a MR sign of lumbar pathology involved the spinal canal.

Imaging of congenital cranial dysinnervation disorders: What radiologist wants to know?

We aim to review the imaging features of congenital cranial dysinnervation disorders. Characteristic imaging findings can define subtypes of these disorders through assessment of cranial nerves, extraocular muscles, orbital, and brain abnormalities. Duane retraction syndrome shows absent or hypoplasic 6th cranial nerve and preserved extraocular muscles (EOM). Mobius syndrome shows absent 7th and 6th cranial nerves, absence of facial colliculus, flattening of the dorsal aspect of the pons, hypoplasia of the pons and medulla, and flattening of the 4th ventricular floor. Congenital fibrosis of the extraocular muscles reveals unilateral or bilateral hypoplasia or aplasia of the 3rd cranial nerve, atrophy of superior rectus and levator palpebrae superioris muscles, and atrophy of the brainstem and cerebellar hemispheres. Horizontal gaze palsy and progressive scoliosis show characteristic split pons sign, butterfly medulla, absent facial colliculi, and spinal scoliosis. HOXA1 Mutations show a bilateral absence of 6th cranial nerves with the underdeveloped inner ear. Pontine Cap Tegmental Dysplasia shows ventral pontine hypoplasia, dorsal tegmental projection into the 4th ventricle, and variable cranial nerve deficits.

Outcomes of microvascular decompression for trigeminal neuralgia with purely venous compression: A systematic review and meta-analysis

OBJECTIVE

Microvascular decompression (MVD) is a commonly-used treatment option for medically-refractory trigeminal neuralgia (TN) with arterial neurovascular compression. Pain control and recurrence rates after MVD in patients with purely venous compression are not well understood. In this systematic review and meta-analysis, we studied outcomes after MVD in patients with purely venous compression and reviewed the operative management in these patients.

METHODS

We performed a systematic review and meta-analysis following the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines. We searched PubMed, Google Scholar, and Scopus databases for studies reporting surgical outcomes after MVD for purely venous compression. Pain control and recurrence rates were extracted and summarized. Studies that reported outcomes after mobilization/decompression compared with coagulation/transection of compressive veins were reviewed.

RESULTS

We identified and included 24 studies with a total of 330 patients in this study. 75.6 % of patients achieved a Barrow Neurological Institute (BNI) I pain score with a mean follow-up of 38.0 months. Pain recurred in 23.1 % of patients at a mean follow-up of 51.4 months. There was no significant difference in pain control outcomes between patients with mobilization/decompression and patients with coagulation/transection of compressive veins.

CONCLUSION

After MVD in patients with venous compression alone, pain control rates were similar to those reported for arterial compression, though recurrence rates were higher. There was no difference between vein coagulation/transection compared to mobilization/decompression. Further studies are needed to determine the optimal treatment paradigm for patients with purely venous compression.

A preliminary study of deep learning-based reconstruction specialized for denoising in high-frequency domain: usefulness in high-resolution three-dimensional magnetic resonance cisternography of the cerebellopontine angle

PURPOSE

Deep learning-based reconstruction (DLR) has been developed to reduce image noise and increase the signal-to-noise ratio (SNR). We aimed to evaluate the efficacy of DLR for high spatial resolution (HR)-MR cisternography.

METHODS

This retrospective study included 35 patients who underwent HR-MR cisternography. The images were reconstructed with or without DLR. The SNRs of the CSF and pons, contrast of the CSF and pons, and sharpness of the normal-side trigeminal nerve using full width at half maximum (FWHM) were compared between the two image types. Noise quality, sharpness, artifacts, and overall image quality of these two types of images were qualitatively scored.

RESULTS

The SNRs of the CSF and pons were significantly higher with DLR than without DLR (CSF 21.81 ± 7.60 vs. 15.33 ± 4.03, p < 0.001; pons 5.96 ± 1.38 vs. 3.99 ± 0.48, p < 0.001). There were no significant differences in the contrast of the CSF and pons (p = 0.225) and sharpness of the normal-side trigeminal nerve using FWHM (p = 0.185) without and with DLR, respectively. Noise quality and the overall image quality were significantly higher with DLR than without DLR (noise quality 3.95 ± 0.19 vs. 2.53 ± 0.44, p < 0.001; overall image quality 3.97 ± 0.17 vs. 2.97 ± 0.12, p < 0.001). There were no significant differences in sharpness (p = 0.371) and artifacts (p = 1) without and with DLR.

CONCLUSION

DLR can improve the image quality of HR-MR cisternography by reducing image noise without sacrificing contrast or sharpness.