Three-dimensional time-of-flight MR angiography in trigeminal neuralgia on a 0.5-T system

Different MRI-based methods for the diagnosis of neurovascular compression in trigeminal neuralgia or hemifacial spasm: A network meta-analysis

BACKGROUND

Accurate preoperative diagnosis of neurovascular compression (NVC) is crucial in the treatment of trigeminal neuralgia (TN) or hemifacial spasm (HFS). At present, there are many magnetic resonance imaging (MRI)-based methods for diagnosing NVC in clinical practice. This network meta-analysis (NMA) aimed to evaluate the diagnostic performance of different MRI-based imaging methods for NVC in patients with TN and HFS.

MATERIALS AND METHODS

Related studies based on a search of PubMed, Embase, Web of Science and the Cochrane Library were retrieved. A two-way analysis of variance model was constructed for the Bayesian NMA to compare the performance of different diagnostic imaging methods.

RESULTS

Our search identified 595 articles, of which 26 studies (including 2085 patients) related to 4 diagnostic imaging methods (3D time-of-flight magnetic resonance angiography (3D TOF MRA), high resolution T2-weighted imaging (HR T2WI), 3D TOF MRA combined with HR T2WI, and 3D multimodal image fusion (MIF) based on 3D TOF MRA combined with HR T2WI) were included in this NMA. The results showed that 3D MIF based on 3D TOF MRA combined with HR T2WI had the highest related sensitivity, the highest superiority index and the largest area under the receiver operating characteristic curve among all the methods.

CONCLUSIONS

3D MIF based on 3D TOF MRA combined with HR T2WI had better diagnostic performance for detecting NVC in patients with TN or HSF than other MRI-based imaging methods. This method can be used as an effective tool for preoperative evaluation of MVD.

Comparison of Clinical Symptoms and Magnetic Resonance Angiographic (MRA) Results in Patients with Trigeminal Neuralgia and Persistent Idiopathic Facial Pain. Medium-Term Outcome after Microvascular Decompression of Cases with Positive MRA Findings

To evaluate whether NC could be demonstrated preoperatively, high-resolution magnetic resonance angiography (MRA) was performed in 287 consecutive patients with TN and persistent idiopathic facial pain (PIFP) on a 0.5-T and a 1-T MR unit. Depending on the clinical symptoms, the TN cases were divided into typical TN and trigeminal neuralgia with non-neuralgic interparoxysmal pain (TNWIP) groups. Microvascular decompression (MVD) was performed in 103 of the MRA-positive cases. The patients were followed up postoperatively for from 1 to 10 years. The clinical symptoms were compared with the imaging results. The value of MRA was assessed on the basis of the clinical symptoms and surgical findings. The outcome of MVD was graded as excellent, good or poor. The clinical symptoms were compared with the type of vascular compression and the outcome of MVD. The MRA image was positive in 161 (56%) of the 287 cases. There were significant differences between the clinical groups: 66.5% of the typical TN group, 47.5% of the TNWIP group and 3.4% of the PIFP group were positive. The quality of the MR unit significantly determined the ratio of positive/negative MRA results. The surgical findings corresponded with the MRA images. Six patients from the MRA-negative group were operated on for selective rhizotomy and no NC was found. Venous compression of the trigeminal nerve was observed in a significantly higher proportion in the background of TNWIP than in that of typical TN on MRA imaging (24.1% and 0.8%, respectively) and also during MVD (31.2% and 1.2%, respectively). Four years following the MVD, 69% of the patients gave an excellent, 23% a good and 8% a poor result. The rate of some kind of recurrence of pain was 20% in the typical TN and 44% in TNWIP group. The rate of recurrence was 57% when pure venous compression was present. The only patient who was operated on from the PIFP group did not react to the MVD. The clinical symptoms and preoperative MRA performed by at least a 1-T MR unit furnish considerable information, which can play a role in the planning of the treatment of TN.

Preoperative evaluation of neurovascular relationship by using contrast-enhanced and unenhanced 3D time-of-flight MR angiography in patients with trigeminal neuralgia

BACKGROUND

Microvascular decompression is an etiological strategy for the therapy of trigeminal neuralgia (TN). Preoperative identification of neurovascular compression, therefore, could have an impact on the determination of appropriate treatment for TN.

PURPOSE

To evaluate the value of contrast-enhanced and unenhanced three-dimensional (3D) time-of-flight (TOF) MR angiography in the visualization of neurovascular relationship in patients with TN.

MATERIAL AND METHODS

Thirty-seven patients with unilateral TN underwent unenhanced and contrast-enhanced 3D TOF MR angiography with a 3.0-T MR system. Images were reviewed by a radiologist blinded to clinical details. Vascular contact with the trigeminal nerve was identified, and the nature of the involved vessels (artery or vein) was determined. All patients underwent microvascular decompression.

RESULTS

In 37 patients with TN, contrast-enhanced 3D TOF MR angiography identified surgically verified neurovascular contact in 35 of 36 symptomatic nerves, and there was no false-positive. Based on surgical findings, the sensitivity of MR imaging was 97.2% and specificity 100%. The nature of the offending vessel was correctly identified in 94.4% of the patients by using the combination of contrast-enhanced and unenhanced MR angiography.

CONCLUSION

Contrast-enhanced 3D TOF MR angiography is useful in the detection of vascular contact with the trigeminal nerve in patients with TN, and this MR imaging in combination with unenhanced MR angiography could help in the identification of the nature of the responsible vessels.

Targeting the cranial nerve: microradiosurgery for trigeminal neuralgia with CISS and 3D-Flash MR imaging sequences

Object.The authors undertook a study to identify magnetic resonance (MR) imaging techniques that can be used reliably during gamma knife surgery (GKS) to identify the trigeminal nerve, surrounding vasculature, and areas of compression.

Methods.Preoperative visualization of the trigeminal nerve and surrounding vasculature as well as targeting the area of vascular compression may increase the effectiveness of GKS for trigeminal neuralgia. During the past years our gamma knife centers have researched different MR imaging sequences with regard to their ability to visualize cranial nerves and vascular structures. Constructive interference in steady-state (CISS) fusion imaging with three-dimensional gradient echo sequences (3D-Flash) was found to be of greatest value in the authors' 25 most recent patients.

In 24 (96%) out of the 25 patients, the fifth cranial nerve, surrounding vessels, and areas of compression could be reliably identified using CISS/3D-Flash. The MR images were acceptable despite patients' history of microvascular decompression, radiofrequency (RF) ablation, or concomitant disease. In one of 25 patients with a history of multiple RF lesions, the visualization was inadequate due to severe trigeminal nerve atrophy.

Conclusions.The CISS/3D-Flash fusion imaging has become the preferred imaging method at the authors' institutions during GKS for trigeminal neuralgia. It affords the best visualization of the trigeminal nerve, surrounding vasculature, and the precise location of vascular compression.

Targeting the cranial nerve: microradiosurgery for trigeminal neuralgia with CISS and 3D-Flash MR imaging sequences

Object. The authors undertook a study to identify magnetic resonance (MR) imaging techniques that can be used reliably during gamma knife surgery (GKS) to identify the trigeminal nerve, surrounding vasculature, and areas of compression.

Methods. Preoperative visualization of the trigeminal nerve and surrounding vasculature as well as targeting the area of vascular compression may increase the effectiveness of GKS for trigeminal neuralgia. During the past years our gamma knife centers have researched different MR imaging sequences with regard to their ability to visualize cranial nerves and vascular structures. Constructive interference in steady-state (CISS) fusion imaging with three-dimensional gradient echo sequences (3D-Flash) was found to be of greatest value in the authors' 25 most recent patients.

In 24 (96%) out of the 25 patients, the fifth cranial nerve, surrounding vessels, and areas of compression could be reliably identified using CISS/3D-Flash. The MR images were acceptable despite patients' history of microvascular decompression, radiofrequency (RF) ablation, or concomitant disease. In one of 25 patients with a history of multiple RF lesions, the visualization was inadequate due to severe trigeminal nerve atrophy.

Conclusions. The CISS/3D-Flash fusion imaging has become the preferred imaging method at the authors' institutions during GKS for trigeminal neuralgia. It affords the best visualization of the trigeminal nerve, surrounding vasculature, and the precise location of vascular compression.