The role of modern imaging modalities on deep brain stimulation targeting for mental illness.

INTRODUCTION: The reversible nature of deep brain stimulation (DBS) brought renewed interest on surgery to medically intractable mental illnesses. The explosion of anatomical and functional imaging has allowed the development of new potential targets and the understanding of historical targets. METHODS: Fifteen patients undergoing stereotactic surgery for movement disorders, at UCLAs interventional MRI operating-room, were studied with fiber tracking. Stereotactic targets and fiber tracking were determined on MRIs using the Schaltenbrand-Wahren atlas for definition in the iPlan software. Cingulate, subcaudate, BA25/CgWM, amygdala, posterior hypothalamus, orbitofrontal cortex, nucleus accumbens, anterior limb of the internal capsule and dorsomedial thalamus were studied. DTI parameters used ranged from 10 to 20mm for voxel size in the x/y/z planes, fiber length was kept constant at 36 mm, and fractional anisotropy (FA) threshold varied from 0.20 to 0.25. RESULTS: Reliable interconnectivity of targets were determined with DTI and related to PET imaging. Mental illness targets were observed with functional and fiber tract maps. This confirmation yields reliability to DTI imaging in order to determine novel targets and enhance the understanding of areas not well understood. CONCLUSIONS: Currently available imaging techniques, the reversibility of DBS to modulate targets promises to bring a brighter future for surgery of mental illness.

Magnetic resonance imaging of the lumbar spine in people without back pain.

BACKGROUND: The relation between abnormalities in the lumbar spine and low back pain is controversial. We examined the prevalence of abnormal findings on magnetic resonance imaging (MRI) scans of the lumbar spine in people without back pain. METHODS: We performed MRI examinations on 98 asymptomatic people. The scans were read independently by two neuroradiologists who did not know the clinical status of the subjects. To reduce the possibility of bias in interpreting the studies, abnormal MRI scans from 27 people with back pain were mixed randomly with the scans from the asymptomatic people. We used the following standardized terms to classify the five intervertebral disks in the lumbosacral spine: normal, bulge (circumferential symmetric extension of the disk beyond the interspace), protrusion (focal or asymmetric extension of the disk beyond the interspace), and extrusion (more extreme extension of the disk beyond the interspace). Nonintervertebral disk abnormalities, such as facet arthropathy, were also documented. RESULTS: Thirty-six percent of the 98 asymptomatic subjects had normal disks at all levels. With the results of the two readings averaged, 52 percent of the subjects had a bulge at at least one level, 27 percent had a protrusion, and 1 percent had an extrusion. Thirty-eight percent had an abnormality of more than one intervertebral disk. The prevalence of bulges, but not of protrusions, increased with age. The most common nonintervertebral disk abnormalities were Schmorl's nodes (herniation of the disk into the vertebral-body end plate), found in 19 percent of the subjects; annular defects (disruption of the outer fibrous ring of the disk), in 14 percent; and facet arthropathy (degenerative disease of the posterior articular processes of the vertebrae), in 8 percent. The findings were similar in men and women. CONCLUSIONS: On MRI examination of the lumbar spine, many people without back pain have disk bulges or protrusions but not extrusions. Given the high prevalence of these findings and of back pain, the discovery by MRI of bulges or protrusions in people with low back pain may frequently be coincidental.

A critical comparison of neurosurgical and otolaryngological approaches to acoustic neuromas.

Neurosurgeons have traditionally advocated the transmeatal suboccipital craniectomy as the procedure of choice in treating acoustic neuromas of all sizes. With this technique, complete tumor removal was achieved in 91% of our patients. Facial motor activity was fully preserved in 59% and it was only partially deficient in an additional 29%. Conversely, recent otological reports have proposed a more flexible attitute in which the size of the tumor dictates the form of surgical therapy. In that scheme, the universally applicable and clinically proven suboccipital craniectomy is replaced by a series of procedures (translabyrinthine, middle fossa, transsigmoidal), each of which differs in its anatomical and technical requirements. This necessity for several operations seems to stem from the failure of any particular approach either to provide adequate visualization of the entire pathological process, or to afford maximum opportunity for complete tumor removal. By employing these various techniques, total capsular removal has been generally achieved in only 71% of cases. A careful comparison and analysis of these individual procedures reaffirms the superiority of the posterior fossa approach.

Prostatic carcinoma producing syndrome of inappropriate secretion of antidiuretic hormone.

The syndrome of inappropriate secretion of antidiuretic hormone was recognized in a sixty-year-old man with a poorly differentiated metastatic adenocarcinoma of the prostate gland. Elevated levels of antidiuretic hormone were found in the patient's serum and in the prostatic tumor but not in the cerebrospinal fluid. The patient's clinical course is detailed, and the pathophysiology of this syndrome is discussed.