Dynamic MRI of Internal Derangement of Temporomandibular Joint

PURPOSE: To evaluate the value of fast field echo(FE) technique in accesing temporOmandibular joint(TMJ) dynamics. MATERIALS AND METHODS: A series of 120 TMJ MRI examinations of 60 symptomatic patients was performed. The fast FE technique was used to provide dynamic images of the TMJs in various phase of mouth opening with a step-bite-block. RESULTS: Among 120 cases, there were 30 cases which were normal, 21 cases of anterior displacement with reduction, 66 cases of anterior displacement without reduction, 11 cases of deformity of menisci, 23 cases of bony deformity, and 3 cases of medial displacement. The menisci and condyles were clearly delineated and the motions of the menisci during jaw opening were well evaluated in both normal and pathologic conditions. CONCLUSION: The dynamic TMJ MRI scan using fast FE technique permits both fast scanning and study of joint dynamics as well as TMJ anatomy.

Clinical and MR Findings of Tethered Cord Syndrome

PURPOSE: Tethered cord syndrome(TCS) is defined as low position of the conus medullaris by the abnormally fixed spinal cord with progressive neurologic deficit MATERIALS AND METHODS: To evaluate the findings of TCS at MRI and its diagnostic value, we performed a retrospective analysis of MRI of 30 patients with emphasis on clinical manifestation, level of conus medullaris, cause of tethering, and associated findings. RESULTS: Clinical presentation included back mass(26 cases), neurogenic bladder(5 cases), urinary incontinence(5 cases), progressive constipation(2 cases), skin dimpling(1 case), gait disturbance(1 case) and club foot (1 case). Neurologic deficit was developed in 11 cases(40% and mean age of these patients at the time of diagnosis was 8.6 years. The most common cause of tethering was lipoma(63%). The tips of conus medullaris were below the level of the second lumbar spine in all patients. The causes of tethering were lipomatous component(spinal lipoma and lipomyelomenigocele) in 67% myelomeningocele in 20%, presacral mass in 7%, thickened filum terminale in 3% and postoperative change in 3%. Associated anomalies included syringomyelia(20%) and hydrocephalus was associated in 3 out of 5 patients who underwent brain MRI. CONCLUSION: MRI clearly delineated the location of conus, tethering of the filum terminale with their causes and associated abnormalities. MRI examination is a very useful diagnostic tool for the early evaluation of TCS and the postoperative follow up.

Determination of main feeding artery with CT findings in cases of ruptured aneurysm of anterior communicating artery

Rupture of anterior communicating artery aneurysm is one of the most important casuses of subarachnoid hemorrhage. Subarachnoid hemorrhage due to ruptured anterior communicating artery aneurysm shows characteristic CT findings, such as forntal hematoma or septum pellucidum hematoma. In some patients with the ruptured aneurysm, direct carotid angiography may be needed. particularly when transfemoral approach is not possible. However, not much have been known about the puncture site selection between the two carotid arteries in relation to the location of hematoma in CT scans. To determine the ideal puncture site of the direct carotid angiography, seventy-five cases of anterior communicating artery aneurysm confirmed by operation from May 1988 to April 1992, were analyzed in terms of relationship between location of hematoma on CT, direction of aneurysm and A1 artery on angiograms. Frontal lobar hematoma was more prevalent than septal hematoma, and was more common on the right side. In cases of lobar hematoma, aneurysm was directed to the ipsilateral side of the hematoma (67%) and was most commonly fed by contralateral A1 artery(75%). Septal bematoma consisted 36% of the cases and among there, midline directed aneurysm was most common, frequently fed by left A1 artery. In conclusion, when performing direct carotid angiography in patients with anterior communicating artery aneurysm, if forntal hematoma is observed on CT, it may be beneficial to puncture contralateral carotid artery. Meanwhile, if hemorrhage of septum pellucidum is observed, it may be better to puncture left carotid artery.