Imaging findings in MR imaging-guided focused ultrasound treatment for patients with essential tremor.

BACKGROUND AND PURPOSE: MR imaging-guided focused sonography surgery is a new stereotactic technique that uses high-intensity focused sonography to heat and ablate tissue. The goal of this study was to describe MR imaging findings pre- and post-ventralis intermedius nucleus lesioning by MR imaging-guided focused sonography as a treatment for essential tremor and to determine whether there was an association between these imaging features and the clinical response to MR imaging-guided focused sonography. MATERIALS AND METHODS: Fifteen patients with medication-refractory essential tremor prospectively gave consent; were enrolled in a single-site, FDA-approved pilot clinical trial; and were treated with transcranial MR imaging-guided focused sonography. MR imaging studies were obtained on a 3T scanner before the procedure and 24 hours, 1 week, 1 month, and 3 months following the procedure. RESULTS: On T2-weighted imaging, 3 time-dependent concentric zones were seen at the site of the focal spot. The inner 2 zones showed reduced ADC values at 24 hours in all patients except one. Diffusion had pseudonormalized by 1 month in all patients, when the cavity collapsed. Very mild postcontrast enhancement was seen at 24 hours and again at 1 month after MR imaging-guided focused sonography. The total lesion size and clinical response evolved inversely compared with each other (coefficient of correlation = 0.29, P value = .02). CONCLUSIONS: MR imaging-guided focused sonography can accurately ablate a precisely delineated target, with typical imaging findings seen in the days, weeks, and months following the treatment. Tremor control was optimal early when the lesion size and perilesional edema were maximal and was less later when the perilesional edema had resolved.

Deep brain stimulation of the subthalamic nucleus improves reward-based decision-learning in Parkinson's disease.

Recently, the subthalamic nucleus (STN) has been shown to be critically involved in decision-making, action selection, and motor control. Here we investigate the effect of deep brain stimulation (DBS) of the STN on reward-based decision-learning in patients diagnosed with Parkinson's disease (PD). We determined computational measures of outcome evaluation and reward prediction from PD patients who performed a probabilistic reward-based decision-learning task. In previous work, these measures covaried with activation in the nucleus caudatus (outcome evaluation during the early phases of learning) and the putamen (reward prediction during later phases of learning). We observed that stimulation of the STN motor regions in PD patients served to improve reward-based decision-learning, probably through its effect on activity in frontostriatal motor loops (prominently involving the putamen and, hence, reward prediction). In a subset of relatively younger patients with relatively shorter disease duration, the effects of DBS appeared to spread to more cognitive regions of the STN, benefiting loops that connect the caudate to various prefrontal areas importantfor outcome evaluation. These results highlight positive effects of STN stimulation on cognitive functions that may benefit PD patients in daily-life association-learning situations.

Trilateral retinoblastoma variant indicative of the relevance of the retinoblastoma tumor-suppressor pathway to medulloblastomas in humans.

Results of recent studies have led investigators to suggest that the retinoblastoma tumor-suppressor (rb) gene plays an underappreciated role in the genesis of brain tumors. Such tumors cause significant rates of mortality in children suffering from hereditary retinoblastoma. It has been assumed that the pineal gland, which is ontogenetically related to the retina, accounts for the intracranial origin of these trilateral neoplasms. To address this issue, the authors describe an unusual trilateral retinoblastoma variant. The authors provide a detailed clinicopathological correlation by describing the case of a child with bilateral retinoblastoma who died of a medulloblastoma. The intraocular and intracranial neoplasms were characterized by performing detailed imaging, histopathological, and postmortem studies. Karyotype analysis and fluorescence in situ hybridization were used to define the chromosomal defect carried by the patient and members of her family. An insertion of the q12.3q21.3 segment of chromosome 13 into chromosome 18 at band q23 was identified in members of the patient's family. This translocation was unbalanced in the proband. The intraocular and cerebellar neoplasms were found to be separate primary neoplasms. Furthermore, the pineal gland was normal and the cerebellar neoplasm arose within the vermis as a medulloblastoma. Finally, the two neoplasms had different and characteristically identifiable cytolological and immunohistochemical profiles. The findings of the present study, taken together with those of recent molecular and transgenic studies, support the emerging concept that rb inactivation is not restricted to central nervous system regions of photoreceptor lineage and that inactivation of this tumor suppressor pathway may be relevant to the determination of etiological factors leading to medulloblastoma in humans.

Calcitonin and spinal fusion.

The authors report on the efficacy of nonsurgical treatment of an older patient with a fractured odontoid process. The patient, an 85-year-old woman, had multiple medical problems that put her at an increased surgery-related risk. Therefore, an alternative approach was elected, including immobilization with a Philadelphia collar and the provision of calcitonin nasal spray. Bone union and clinical recovery were achieved within 8 weeks of initiating the nasal calcitonin therapy (12 weeks postinjury). Considering the patient's age, comorbidities, and the severity of the fracture, the recovery period was unusually short. The authors believe that calcitonin played a pivotal role in the healing process of the fractured odontoid bone. There is no question that the fusion in this patient could be unrelated to the medical therapy. This description of one patient, as well as the lack of a large randomized study, precludes any scientific conclusions. Nevertheless, the authors believe that the development of a successful fusion in this high-risk patient should be reported as an observation that merits confirmation and study. The authors also discuss the physiological effects of calcitonin and the research and clinical experience with this hormone in different conditions affecting bone.

Complications of posterior lumbar interbody fusion when using a titanium threaded cage device.

OBJECT: The authors reviewed their series of patients to quantify clinical and radiographic complications in those who underwent a posterior lumbar interbody fusion (PLIF) procedure in which a threaded interbody cage (TIC) was implanted. METHODS: Sixty-seven patients underwent a posterior lumbar interbody fusion procedure in which a TIC was used. The authors excluded patients who underwent procedures in which other instrumentation was used or a nondorsal approach was performed. Fifteen percent of the cases (10 patients) were complicated by laceration of the dura. In three cases, bilateral implantation could not be performed. The average blood loss was 670 ml for all cases, and blood transfusion was required in 25% of the cases (17 patients). The rate of minor wound complication was 4.5% (three patients). One patient died. The average period of hospitalization was 4.25 days. Twenty-eight patients (42%) experienced significant low-back pain 3 months postoperatively, and in 10 (15%) of these cases it persisted beyond 1 year. In 10 patients postoperative radiculopathy was demonstrated, and magnetic resonance imaging revealed epidural fibrosis in six patients, arachnoiditis in one, and a recurrent disc herniation in one. One patient incurred a permanent motor deficit with sexual dysfunction. Pseudarthrosis was suggested radiographically with evidence of motion on lateral flexion-extension radiographs (10 cases), lucencies around the implants (seven cases), and posterior migration of the cage (two cases). Additional procedures (in 14 patients) consisted primarily of transverse process fusion with pedicle screw and plate augmentation for persistent back pain and radiographically demonstrated signs of spinal instability. In two patients with radiculopathy, migration of the TIC required that it be removed. Graft material that extruded from one implant necessitated its removal. In one patient scarectomy was performed. CONCLUSIONS: Our high incidence of TIC-related complications in PLIF is inconsistent with that reported in previous studies.

Frameless stereotaxy for transsphenoidal surgery.

OBJECTIVE: To evaluate the utility of performing transsphenoidal surgery with computer-assisted image guidance. METHODS: Thirty-seven patients underwent transsphenoidal surgery in which a frameless stereotactic system was used to confirm the trajectory to the sella and to locate the anatomic midline. This technique was compared with our standard method of using an image intensifier to confirm the approach (n = 43). The numbers of complications associated with the approach, the times required to set up and perform each operation, and the average costs for each group were compared. RESULTS: There were no complications attributable to inaccurate localization from the neuronavigational system. Additional setup time was necessary to calibrate and register the system; this represented a mean of 17 minutes in transsphenoidal procedures performed for the first time (n = 30), whereas reoperations required an average of 22 minutes (n = 7) (P < 0.05). The operative times, defined as time from incision to closure, were not statistically different (P = 0.38). To reduce assistant variation, a subset of this group in which the same assistant was used (n = 18) was analyzed. The additional setup time was reduced to a mean of 12 minutes (P < 0.05). The total case times were actually reduced in this group (127 versus 133 min), but this was not statistically significant (P = 0.75). Fluoroscopy was not required when frameless stereotaxy was used. The cost savings were partially offset by the cost of the preoperative computed tomographic study necessary for fiducial registration and the additional cost of setup time in the operating room. When all factors were analyzed, an additional cost to the patient of $318.00 was noted. The image guidance in axial, coronal, and sagittal planes provided by frameless stereotaxy was subjectively beneficial; it increased our confidence with the approach to the sella and intraoperative localization and was particularly helpful in reoperations where standard anatomic landmarks were distorted. CONCLUSION: Frameless stereotaxy is a technology that provides continuous, three-dimensional information for localization and surgical trajectory to the surgeon and can be applied to transsphenoidal surgery with minimal additional cost and time requirements.

Small cell lung carcinoma causing epidural hematoma: case report.

BACKGROUND: Epidural hematoma usually stems from trauma, yet it may occur from other etiologies, including neoplasms. We present a case of small cell lung carcinoma with focal hemorrhagic central nervous system metastasis producing an epidural hematoma, and review the associated literature. CLINICAL PRESENTATION: A 67-year-old man was undergoing chemotherapy for small cell carcinoma of the lung. Acute neurologic deterioration resulted from a large parietal epidural hematoma of non-traumatic origin. INTERVENTION: The clot was evacuated via craniotomy with marked improvement in his clinical state. Metastatic tumor was present in the scalp, muscle, bone, and dura. No gross brain invasion was apparent. CONCLUSIONS: This case illustrates the wisdom of including metastatic disease in the differential diagnosis of intracranial hemorrhage. Even epidural hematoma may result from metastatic cancer. The prevalence of lung carcinoma and the aging of the population may produce an increased appearance of this phenomenon. Appropriate evaluation and rapid intervention will aid the patient in both the acute and long-term phases, and should improve the quality of survival.

Solitary sarcoid granuloma of the cerebellopontine angle: a case report.

BACKGROUND: Sarcoidosis involves the nervous system about 5% of the time and usually manifests as a granulomatous inflammation of the basal meninges and hypothalamus. Cases which are strictly isolated to the central nervous system occur infrequently; rarely, they may present as an intracranial mass. METHODS: We present the case of a solitary sarcoid granuloma at the cerebellopontine angle in a 42-year-old female who presented with headache, facial numbness, and hearing loss. RESULTS: A suboccipital craniectomy was performed and the lesion was noted to be grossly adherent to the lower cranial nerves and skull base. The lesion was misdiagnosed as a meningioma with preoperative magnetic resonance imaging and intraoperative histology, and perhaps additional morbidity resulted. CONCLUSION: We present this case in order to demonstrate the importance of differentiating these dural-based lesions and propose that cases of neurosarcoidosis presenting as a solitary granuloma be treated with surgical debulking and immunosuppression.

Admission prediction of expected final myocardial infarct size using weighted ST-segment, Q wave, and T wave measurements.

Formulas for predicting final acute myocardial infarction (MI) size from ST-segment deviation on an initial electrocardiogram were proposed by Aldrich et al. for anterior and inferior infarct locations. This study of 529 patients who did not receive thrombolytic therapy was performed to determine the effectiveness of the Aldrich formulas for predicting final QRS MI size; to propose new formulas for predicting final MI size using ST-segment deviation, Q wave, and T wave information in a development population of 322 patients; and to evaluate the new formulas in a randomly selected population of 207 patients. The Aldrich formulas achieved correlations with final infarct size of r = .40 for anterior and r = .43 for inferior MI locations in the present population which are weaker than those previously reported. Formulas that consider electrocardiographic parameters in addition to ST-segment deviation were proposed for both anterior and inferior final MI size. In the test set of 207 patients, these models explained 16.9% and 15.2% of the variation in final MI size for anterior and inferior locations respectively. They may prove useful in assessing the extent of myocardial salvage where interventions are to be tested.