Trigeminal neuralgia: Assessment with T2 VISTA and FLAIR VISTA fusion imaging

A Systematic Review of the Role of Magnetic Resonance Imaging in the Diagnosis and Detection of Neurovascular Conflict in Patients With Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a debilitating disorder causing severe, episodic, unilateral stabbing facial pain disturbing enough to disrupt the activities of daily life. Classic TN is caused due to compression injury of the trigeminal nerve at the cistern segment caused by either an artery or a vein, referred to as neurovascular contact or conflict (NVC). Magnetic resonance imaging (MRI) has been the standard tool for the diagnosis of NVC. This study aimed to determine the incidence of NVC in TN, as identified by MRI, assess the various MRI grading patterns among patients with TN, and identify the vessels primarily involved in NVC. A systematic search of studies that used MRI for the diagnosis of TN in reference to NVC was conducted on DOAJ and PubMed/PubMed Central. Data were extracted and entered into a Microsoft Excel spreadsheet. The outcomes measured were the incidence of NVC as shown in MRI, vessels involved in NVC, and MRI grading patterns. We identified and selected 20 studies that fulfilled inclusion/exclusion criteria. In total, 1,436 patients were enrolled in all included studies. The type of MRI used was 1.5 T or 3 T MRI. The mean age of the patients varied from 49 to 63 years, with an equivalent male-to-female ratio. NVC was seen in 1,276 cases out of 1,436 cases (88.85%) of TN on the ipsilateral side, as shown by MRI. The vessels involved were arteries in 80-90% of the cases, followed by veins. Among the arteries, the superior cerebellar artery was the most common artery (80-90% of cases). The grades of NVC as assessed by MRI included grades I, II, and III with varied proportions in different studies. NVC is a common problem in TN, wherein there is compression at the nerve root entry zone, and it shows a strong predilection for the elderly population. MRI seems to be a novel imaging diagnostic investigation to identify NVC associated with TN. Moreover, NVC grading must be done with MRI so that it may help the surgeon in stratifying the patient's treatment.

Chinese expert consensus on minimally invasive interventional treatment of trigeminal neuralgia

BACKGROUND AND PURPOSE

Trigeminal neuralgia is a common condition that is associated with severe pain, which seriously affects the quality of life of patients. When the efficacy of drugs is not satisfactory or adverse drug reactions cannot be tolerated, minimally invasive interventional therapy has become an important treatment because of its simple operation, low risk, high repeatability and low cost. In recent years, minimally invasive interventional treatments, such as radiofrequency thermocoagulation (RF) of the trigeminal nerve and percutaneous microcompression (PMC), have been widely used in the clinic to relieve severe pain in many patients, however, some related problems remain to be addressed. The Pain Association of the Chinese Medical Association organizes and compiles the consensus of Chinese experts to standardize the development of minimally invasive interventional treatment of trigeminal neuralgia to provide a basis for its clinical promotion and application.

MATERIALS AND METHODS

The Pain Association of the Chinese Medical Association organizes the Chinese experts to compile a consensus. With reference to the evidence-based medicine (OCEBM) system and the actual situation of the profession, the Consensus Development Committee adopts the nominal group method to adjust the recommended level.

RESULTS

Precise imaging positioning and guidance are the keys to ensuring the efficacy and safety of the procedures. RF and PMC are the most widely performed and effective treatments among minimally invasive interventional treatments for trigeminal neuralgia.

CONCLUSIONS

The pain degree of trigeminal neuralgia is severe, and a variety of minimally invasive intervention methods can effectively improve symptoms. Radiofrequency and percutaneous microcompression may be the first choice for minimally invasive interventional therapy.

The changing face of trigeminal neuralgia-A narrative review

OBJECTIVE

This narrative review aims to update the reader on the new classification of trigeminal neuralgia (TN), clinical signs, pathophysiologic evidence, and their implications on management. This review is based on the authors' collective experience and knowledge of the literature in addition to a literature search.

BACKGROUND

In recent years, the phenotype of TN has been intensively studied leading to discrete groups of patients. These include patients with TN with additional continuous pain, and patients with and without neurovascular compression of the trigeminal dorsal root entry zone. A number of associated clinical signs such as tearing and sensory changes need further research.

METHODS

The literature on TN was searched in PubMed with the aims of providing evidence for the recently published third edition of the International Classification of Headache Disorders (ICHD) and update the clinical phenotype and management of the TN subcategories.

RESULTS

The ICHD's new classification for TN is based on reliable clinical data, imaging, and neurophysiologic studies. The TN classification reflects current knowledge and has improved the possibility for clinicians to choose adequate management options. However, there is a lack of effective, safe drugs for the management of TN and sparse, robust data on neurosurgical options.

CONCLUSION

Research into all aspects of TN-diagnosis, pharmacotherapy, surgery, long-term management prognosis, and natural history-is needed. Research should adhere to the ICHD's schema for TN. Improved drugs are needed along with rigorous research into surgical options and their efficacy for different subtypes of TN.

Visualization of cerebellar peduncles using diffusion tensor imaging

The cerebellum communicates with the cerebral cortex via the superior, middle, and inferior cerebellar peduncles (CPs). To preserve the structure and function of the brainstem and cerebellum, which is compressed in various pathological conditions, it is important to delineate the spatial interrelationship of the CPs for presurgical planning and intraoperative guidance. Diffusion tensor tractography (DTT) is a technique capable of depicting the major fiber bundles in CPs. However, routine use of this technology for brainstem visualization remains challenging due to the anatomical smallness and complexity of the brainstem and susceptibility-induced image distortions. Here, we attempt to visualize CPs using high-resolution DTT in a commercial equipment for the application of this technique in normal clinical settings. DTT and fast imaging employing steady-state acquisition-cycled phases (FIESTA) of the whole brainstem were performed. We rendered the DTT fiber bundle using a region-of-interest-based fiber tracking method onto the structural image generated in FIESTA by automatic image coregistration. Fibers of the CPs were clearly visualized by DTT. The DTT-FIESTA overlaid image revealed the cross-sectional and three-dimensional anatomy of the pyramidal tract and the ascending sensory fibers, in addition to the CPs. This could indicate a geometrical relationship of these fibers in the brainstem. The CPs could be visualized clearly using DTT within clinically acceptable scanning times. This method of visualizing the exact pathway of fiber bundles and cranial nerves in the skull base helps in the planning of surgical approaches.

Atrophic Changes and Diffusion Abnormalities of Affected Trigeminal Nerves in Trigeminal Neuralgia Using 7-T MRI

BACKGROUND

Magnetic resonance imaging (MRI) has been widely used for visualizing trigeminal nerves in trigeminal neuralgia.

OBJECTIVE

To assess atrophy and diffusion abnormalities of affected trigeminal nerves in trigeminal neuralgia with 7-T MRI.

METHODS

In this prospective study, 14 patients (mean age 49 years; range 31-64 years) with trigeminal neuralgia underwent 7-T MRI. We measured trigeminal nerve volumes along their course through the pontocerebellar cistern. We also evaluated fractional anisotropy (FA) and quantitative anisotropy (QA) values within cisternal segment and pontine nuclei of the affected-side and unaffected-side trigeminal nerves, using diffusion tensor imaging (DTI). Associations between DTI metrics and Barrow Neurological Institute (BNI) pain scores were examined.

RESULTS

The volumes were significantly smaller for the affected trigeminal nerves (33.83 ± 23.12 mm3) than for the unaffected ones (47.76 ± 32.48 mm3; p = 0.008). Cisternal segment FA and QA values were significantly lower in affected trigeminal nerves than in unaffected ones. However, DTI measurements in the pontine nuclei revealed no significant differences between affected-side and unaffected-side trigeminal nerves. No DTI metrics significantly correlated with BNI pain scores.

CONCLUSION

Our results suggest that 7-T MRI allows identifications of atrophy and diffusion abnormalities of trigeminal nerves in trigeminal neuralgia.

Preoperative evaluation of neurovascular relationship in trigeminal neuralgia by three-dimensional fast low angle shot (3D-FLASH) and three-dimensional constructive interference in steady-state (3D-CISS) MRI sequence

OBJECTIVE

The purpose of the study was to evaluate the value of high-resolution three-dimensional fast low angle shot (3D-FLASH) and three-dimensional constructive interference in steady-state (3D-CISS) MRI sequence solely or the combination of both in the visualization of neurovascular relationship in patients with trigeminal neuralgia (TN).

METHODS

65 patients with unilateral TN underwent 3D-FLASH and 3D-CISS imaging were retrospectively studied. Neurovascular relationship at the intracisternal segment of trigeminal nerve was reviewed by two experienced neuroradiologist, who was blinded to the clinical details. The imaging results were compared with the operative findings in all patients.

RESULTS

The accuracy and positive rates of the 3D-FLASH + CISS imaging (98.46, 92.31%) in judging the symptomatic side according to the presence of vascular contacts were higher than those of 3D-CISS (90.77%, 84.62) or 3D-FLASH (89.23, 83.08%) sequence. In addition, the statistical analysis showed the sensitivity and accuracy of 3D-FLASH + CISS imaging was higher than that of 3D-FLASH (p < 0.05). The 3D-FLASH + CISS imaging was more accurate in determining the type of offending vessel than 3D-CISS or 3D-FLASH imaging.

CONCLUSION

The retrospective study demonstrates that the combination of 3D-FLASH with 3D-CISS sequence well delineates the relationship between intracisternal segment of trigeminal nerve and adjacent vessels in terms of increased positive rates and accuracy. Advances in knowledge: The study firstly dealt with the combination of 3D-CISS and 3D-FLASH imaging in TN.

Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a sudden, severe, brief, stabbing, and recurrent pain within one or more branches of the trigeminal nerve. Type 1 as intermittent and Type 2 as constant pain represent distinct clinical, pathological, and prognostic entities. Although multiple mechanism involving peripheral pathologies at root (compression or traction), and dysfunctions of brain stem, basal ganglion, and cortical pain modulatory mechanisms could have role, neurovascular conflict is the most accepted theory. Diagnosis is essentially clinically; magnetic resonance imaging is useful to rule out secondary causes, detect pathological changes in affected root and neurovascular compression (NVC). Carbamazepine is the drug of choice; oxcarbazepine, baclofen, lamotrigine, phenytoin, and topiramate are also useful. Multidrug regimens and multidisciplinary approaches are useful in selected patients. Microvascular decompression is surgical treatment of choice in TN resistant to medical management. Patients with significant medical comorbidities, without NVC and multiple sclerosis are generally recommended to undergo gamma knife radiosurgery, percutaneous balloon compression, glycerol rhizotomy, and radiofrequency thermocoagulation procedures. Partial sensory root sectioning is indicated in negative vessel explorations during surgery and large intraneural vein. Endoscopic technique can be used alone for vascular decompression or as an adjuvant to microscope. It allows better visualization of vascular conflict and entire root from pons to ganglion including ventral aspect. The effectiveness and completeness of decompression can be assessed and new vascular conflicts that may be missed by microscope can be identified. It requires less brain retraction.

Trigeminal neuralgia (part I): Revisiting the clinical phenotype

Aims

We conducted a cross-sectional study to re-examine the clinical profile of patients with a clinical diagnosis of classical trigeminal neuralgia (CTN).

Methods

Inclusion criteria consisted of the International Headache Society’s published classification of CTN. For the specific purposes of the study, features such as autonomic signs, persistent background pain, attack durations of >2 minutes and reports of pain-related awakening were included. The demographic and clinical phenotype of each patient were carefully recorded for analysis.

Results

The study cohort consisted of 81 patients and based on reported attack duration these were divided into short (≤ 2 minutes, n = 61) and long (> 2 minutes, n = 20) groups for further analysis. The group with short attack duration neatly fit most of the criteria for CTN while the long attack group presents a more challenging diagnosis. There were no significant differences in pain severity, quality and location between the short and long attack groups. The frequency of persistent background pain was significantly higher in the long (70%) compared to the short attack group (29.5%, p = 0.001). There were significantly more reports of pain-related awakenings in the long (55%) than in the short attack groups (29.5%, p = 0.04). There were no significant differences in the frequency of autonomic signs between the short (21.3%) and long attack groups (40%, p = 0.1). In the short attack group, the presence of autonomic signs was significantly associated with longer disease duration, increased pain-related awakenings, and a reduced prognosis.

Conclusion

There are clear diagnostic criteria for CTN but often patients present with features, such as long pain attacks, that challenge such accepted criteria. In our cohort the clinical phenotype of trigeminal, neuralgiform pain with or without autonomic signs and background pain was observed across both short and long attack groups and the clinical implications of this are discussed.

Trigeminal neuralgia occurs and recurs in the absence of neurovascular compression

Object

Vascular compression of the trigeminal nerve is the most common factor associated with the etiology of trigeminal neuralgia (TN). Microvascular decompression (MVD) has proven to be the most successful and durable surgical approach for this disorder. However, not all patients with TN manifest unequivocal neurovascular compression (NVC). Furthermore, over time patients with an initially successful MVD manifest a relentless rate of TN recurrence.

Methods

The authors performed a retrospective review of cases of TN Type 1 (TN1) or Type 2 (TN2) involving patients 18 years or older who underwent evaluation (and surgery when indicated) at Oregon Health & Science University between July 2006 and February 2013. Surgical and imaging findings were correlated.

Results

The review identified a total of 257 patients with TN (219 with TN1 and 38 with TN2) who underwent high-resolution MRI and MR angiography with 3D reconstruction of combined images using OsiriX. Imaging data revealed that the occurrence of TN1 and TN2 without NVC was 28.8% and 18.4%, respectively. A subgroup of 184 patients underwent surgical exploration. Imaging findings were highly correlated with surgical findings, with a sensitivity of 96% for TN1 and TN2 and a specificity of 90% for TN1 and 66% for TN2.

Conclusions

Magnetic resonance imaging detects NVC with a high degree of sensitivity. However, despite a diagnosis of TN1 or TN2, a significant number of patients have no NVC. Trigeminal neuralgia clearly occurs and recurs in the absence of NVC.