Won S. Kim

Computed tomography of dural sinus thrombosis.

The four patients presented here demonstrate the value of contrast enhanced CT in the diagnosis and serial evaluation of dural sinus thrombosis. Two patients were young women using oral contraceptives; another patient had lateral sinus thrombosis complicating mastoiditis; a fourth patient developed superior sagittal sinus thrombosis following hip surgery. Improvements in CT diagnosis, including the use of thin sections for evaluation of the deep venous structures and lateral sinuses complemented by multiplanar reconstruction or direct coronal scanning, are discussed. Sequential scans for following the progress of two patients treated by barbiturate coma added to the understanding of dural sinus occlusive disease.

Magnetic resonance imaging for evaluating neurogenic dysphagia

Dysphagia due to CNS pathology usually stems from one of two patterns of disease: (1) bilateral corticobulbar tract dysfunction (“pseudobulbar palsy”) or (2) pontomedullary dysfunction (“bulbar palsy”). Computed tomography (CT) has proved to be useful for evaluating the brainstem in patients with neurogenic dysphagia. Nonetheless, artifacts are common in CT imaging of the posterior fossa. Also, direct sagittal imaging is not usually obtainable by CT in adult patients.Magnetic resonance imaging (MRI), in contrast to CT, simultaneously gathers sequential images in the same plane and can obtain direct reconstructions in any plane of interest. MRI has proven to be more sensitive than CT in demonstrating lesions of the brain, such as demyelinating (e.g., multiple sclerosis) and ischemic diseases, (Brant-Zawadzki et al. 1984, Bradley et al. 1984, Bydder et al. 1982, Sheldon et al. 1985) as well as neoplastic masses that may produce neurogenic dysphagia (Lee et al. 1985, Zimmerman et al. 1986).Five patients with dysphagia are reported for whom MRI was valuable in detecting and characterizing their lesions of the brainstem and the cerebral hemispheres.

Computed tomography in calcified renal masses.

Five patients with calcified renal masses were evaluated with angiography and postcontrast computed tomography (CT). Computed tomography showed no contrast enhancement of the mass in four patients, three with avascular hypernephromas and one with a renal cyst; in each case, the lesion was totally avascular on angiography. In the fifth case, the lesion enhanced on CT and proved to be an aneurysm. It is concluded that angiography is most informative in calcifled renal masses that demonstrate contrast enhancement on CT.

Deep brain stimulation for the treatment of Parkinson’s disease: efficacy and safety

Deep brain stimulation (DBS) surgery has become increasingly utilized in the treatment of advanced Parkinsons disease. Over the past decade, a number of studies have demonstrated that DBS is superior to best medical management in appropriately selected patients. The primary targets for DBS in Parkinsons disease include the subthalamic nucleus and the internal segment of the globus pallidus, both of which improve the cardinal motor features in Parkinsons disease. Recent randomized studies have revealed that both targets are similarly effective in treating the motor symptoms of Parkinsons disease, but emerging evidence suggests that the globus pallidus may be the preferred target in many patients, based on differences in nonmotor outcomes. Here, we review appropriate patient selection, and the efficacy and safety of DBS therapy in Parkinsons disease. Best outcomes are achieved if the problems of the individual patient are considered when evaluating surgical candidates and considering whether the subthalamic nucleus or the globus pallidus internus should be targeted.

Diffusion tractography imaging–guided frameless linear accelerator stereotactic radiosurgical thalamotomy for tremor: case report

Essential tremor and Parkinsons disease-associated tremor are extremely prevalent within the field of movement disorders. The ventral intermediate (VIM) nucleus of the thalamus has been commonly used as both a neuromodulatory and neuroablative target for the treatment of these forms of tremor. With both deep brain stimulation and Gamma Knife radiosurgery, there is an abundance of literature regarding the surgical planning, targeting, and outcomes of these methodologies. To date, there have been no reports of frameless, linear accelerator (LINAC)-based thalomotomies for tremor. The authors report the case of a patient with tremor-dominant Parkinsons disease, with poor tremor improvement with medication, who was offered LINAC-based thalamotomy. High-resolution 0.9-mm isotropic MR images were obtained, and simulation was performed via CT with 1.5-mm contiguous slices. The VIM thalamic nucleus was determined using diffusion tensor imaging (DTI)-based segmentation on FSL using probabilistic tractography. The supplemental motor and premotor areas were the cortical target masks. The authors centered their isocenter within the region of the DTI-determined target and treated the patient with 140 Gy in a single fraction. The DTI-determined target had coordinates of 14.2 mm lateral and 8.36 mm anterior to the posterior commissure (PC), and 3 mm superior to the anterior commissure (AC)-PC line, which differed by 3.30 mm from the original target determined by anatomical considerations (15.5 mm lateral and 7 mm anterior to the PC, and 0 mm superior to the AC-PC line). There was faint radiographic evidence of lesioning at the 3-month follow-up within the target zone, which continued to consolidate on subsequent scans. The patient experienced continued right upper-extremity resting tremor improvement starting at 10 months until it was completely resolved at 22 months of follow-up. Frameless LINAC-based thalamotomy guided by DTI-based thalamic segmentation is a feasible method for achieving radiosurgical lesions of the VIM thalamus to treat tremor.