In patients with clinical features of trigeminal neuralgia, MRA is commonly used as a complementary study to high- resolution MRI in assessing for vascular compression of the CN V with sensitivities of combined MRI with MRA ranging from 97% to 100%, specificities reported as 100%, and good to strong agreement found compared with surgical findings [69,71-73,76]. One group reported a lower sensitivity (50% at 3T and 33% at 1.5T) of combined high-resolution MRI with MRA for detection of neurovascular compression of CN V by smaller vessels such as the anterior inferior cerebellar artery [71]. Cranial Neuropathy In patients with clinical features of trigeminal neuralgia, 3-D heavily T2-weighted MRI sequences, MRA, and a combination of these techniques are commonly used noninvasive methods for characterizing the anatomy of vascular loops potentially compressing the fifth nerve and correlate well with surgical findings [23,68-76]. Congruence rates of imaging and intraoperative findings for neurovascular contact range from 83% to 100% [68- 70,72,75,78]. Both false-positive and false-negative imaging studies occur when assessing for neurovascular contact in the setting of trigeminal neuralgia; consequently, MRI is supportive rather than diagnostic in selecting candidates for microvascular decompression and should be interpreted in the context of the site of symptoms [69,73-75,78]. Imaging evidence of vascular trigeminal nerve root compression, the degree of compression, location of contact, and nerve volume may have prognostic value [73,77,79-81]. Trigeminal nerve size measurements have been reported as smaller on the symptomatic side in trigeminal neuralgia as measured from thin-cut MRI [82-84]. Preoperative imaging is useful for surgical planning [85]. Advanced MRI techniques including diffusion tensor imaging (DTI), functional MRI, and voxel-based morphometry are being used to research the pathophysiology of trigeminal neuralgia.
Cranial Neuropathy. In patients with clinical features of trigeminal neuralgia, MRA is commonly used as a complementary study to high- resolution MRI in assessing for vascular compression of the CN V with sensitivities of combined MRI with MRA ranging from 97% to 100%, specificities reported as 100%, and good to strong agreement found compared with surgical findings [69,71-73,76]. One group reported a lower sensitivity (50% at 3T and 33% at 1.5T) of combined high-resolution MRI with MRA for detection of neurovascular compression of CN V by smaller vessels such as the anterior inferior cerebellar artery [71]. Cranial Neuropathy In patients with clinical features of trigeminal neuralgia, 3-D heavily T2-weighted MRI sequences, MRA, and a combination of these techniques are commonly used noninvasive methods for characterizing the anatomy of vascular loops potentially compressing the fifth nerve and correlate well with surgical findings [23,68-76]. Congruence rates of imaging and intraoperative findings for neurovascular contact range from 83% to 100% [68- 70,72,75,78]. Both false-positive and false-negative imaging studies occur when assessing for neurovascular contact in the setting of trigeminal neuralgia; consequently, MRI is supportive rather than diagnostic in selecting candidates for microvascular decompression and should be interpreted in the context of the site of symptoms [69,73-75,78]. Imaging evidence of vascular trigeminal nerve root compression, the degree of compression, location of contact, and nerve volume may have prognostic value [73,77,79-81]. Trigeminal nerve size measurements have been reported as smaller on the symptomatic side in trigeminal neuralgia as measured from thin-cut MRI [82-84]. Preoperative imaging is useful for surgical planning [85]. Advanced MRI techniques including diffusion tensor imaging (DTI), functional MRI, and voxel-based morphometry are being used to research the pathophysiology of trigeminal neuralgia.