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Background: Accurate evaluation of the electrode position in subthalamic nucleus (STN) after deep-brain stimulation (DBS) has rarely been verified before., Objective: We superimposed the postoperative thin-sliced computed tomography (CT) on the preoperative magnetic resonance imaging (MRI), and the positional information of the implanted electrodes with electrophysiological data was reflected on MRI. The accuracy of this method was assessed by comparing STN demarcated on this method (M-STN) with the electrophysiologically defined STN (E-STN) and with STN on the Schaltenbrand-Wahlen atlas (SW-STN)., Methods: In 16 patients, T2-weighted MRI was obtained before surgery and STN boundary was demarcated. Seven days after surgery, the position of the implanted electrodes was localized on thin-sliced CT and superimposed on the preoperative MRI. Their accordance with E-STN and compatibility of M-STN or SW-STN with E-STN were statistically assessed., Results: In all patients, postoperative CT corresponded well with the preoperative MRI. Between inside and outside the boundaries of M-STN, the mean amplitude levels of multiunit neuronal activities were significantly different on both the rostral and caudal sides (P < .0001), and the marginal errors between M- and E-STN were 0.388 +/- 0.755 mm (mean +/- standard deviation) at the rostral margin and 0.271 +/- 0.738 mm at the caudal margin. Statistical comparison disclosed that M-STN was more similar to E-STN than SW-STN on the axial and coronal images., Conclusion: M-STN corresponded well with the high-amplitude area on the electrophysiological data, and the MRI-CT fusion method allowed sufficiently accurate assessment of the electrode position after DBS surgery.

A new device, modified from the Nucleotome (Surgical Dynamics, Alameda, CA), was used for stereotactic aspiration of deep brain hematomas. Real-time monitoring by computed tomography allows a very safe procedure, and the risk of aspirating the surrounding brain is avoided. The technique was applied in 13 cases of deep brain hematomas. The intraoperative computed tomographic scan demonstrated that the mass effect was always immediately improved. Aspiration was stopped when the midline shift disappeared or was dramatically reduced. For most of the cases, a total aspiration of the hematoma was not needed (mean value of the aspiration rate of 71, 5%). No rebleeding and no complication related to the technique was observed. This technique was easily performed in emergency conditions.

Five AIDS patients with previously diagnosed and treated toxoplasmosis presented with hyperdense precontrast CT approximately 6 months after the CNS infection. An MR study was performed in all cases. The CT hyperdensities were characterized on MR by a high signal intensity on T1 images in four cases. In two of these, pathological correlation confirmed hemorrhage. In the fifth case, MR findings were consistent with calcification, which was verified by pathological examination.

The authors report the results of 89 vertebral biopsies performed under CT guidance, classified according to the type of pathology and the site of the lesion. A correct diagnosis was obtained in 89 cases. No complication was observed. The value of CT guidance in vertebral biopsy is emphasized.

Twenty-seven percutaneous trephine biopsies of thoracic vertebral bodies were performed under CT guidance using a new intertransversocostal approach avoiding the pleura and nerve roots. Accurate diagnosis was obtained in 25 of 27 cases. No complications were encountered.

Two patients treated by chemotherapy for a non-Hodgkin malignant lymphoma developed focal neurological symptoms including disorientation, hemoplegia, and cortical blindness 5 and 15 days after the end of a polychemotherapy course, including methotrexate and vindesine. In both patients ECG and blood pressure were normal. Case 1 had a slight increase of protein level without cells on CSF examination and presented with a paralytic ileus. Case 2 developed an inappropriate antidiuretic hormone secretion (IADHS) syndrome. In both cases, noncontrast CT scans showed bilateral, symmetrical low density areas within the temporooccipital regions. Postcontrast CT images stressed major cortical and subcortical enhancement predominantly over the gray matter. In Case 2 the lesions also affected the right parietal lobe. Magnetic resonance scans 2-3 weeks after the onset of neurological symptoms demonstrated low intensity signal lesions on T1-weighted images and bright signal on T2-weighted images. In Case 1 the visual deficit failed to regress and in Case 2 the patient died 2 months later because of the natural evolution of her lymphoma. The clinical and radiological data suggested that a vascular ischemic process was responsible for the cerebral lesions in these two patients. As Vinca alkaloids and not methotrexate have been implicated as a cause of cortical blindness, and as our two patients presented signs of overdose of vindesine (paralytic ileus and IADHS), we suggest that the neurological and radiological abnormalities in our patients may have been due to neurotoxicity of vindesine.

About 37 cases of non-traumatic spinal cord and cauda-equina compression, the authors emphasize the value of CT-scan study after intra-thecal injection of water-soluble contrast-medium. This exploration gives accurate informations about the involvement of both spinal and para-spinal spaces. These data are helpful diagnosis purpose and for the choice of therapeutic especially when surgical procedure is decided.