Relationship between PET-FDG and MRI apparent diffusion coefficients in brain tumors.

AIM: The aim of this study was to investigate the relationship between 2-deoxy-2[(18)F]fluoro-D-glucose ([(18)F]FDG) positron emission tomography (PET) and diffusion-weighted magnetic resonance imaging (DWI) with apparent diffusion coefficients (ADC) in brain tumors. METHODS: Fifteen patients with 18 metastatic brain lesions underwent gadolinium-enhanced fast spoiled gradient echo (Gd-FSPGR), DWI with ADC maps, and [(18)F]FDG PET. Spherical three-dimensional tumor and contralateral control regions of interest (ROIs) were drawn on Gd-FSPGR, ADC and PET images, Gd-FSPGR being the target for statistical parametric mapping with realigned ADC and PET to calculate ROI ratios; linear regression analysis was performed. RESULTS: An inverse correlation (r(2)=0.2746, P=0.0256) was found between PET and ADC ratios; plotting ratios: when PET ratios were high, ADC ratios were low, while, when ADC ratios were high, PET ratios were low. CONCLUSIONS: Our preliminary data suggest an inverse relationship between PET and ADC indices. Hypercellular areas could increase impedance to water diffusion, resulting in low ADC values and high [(18)F]FDG uptake, while lower cellularity areas show increased ADC with decreased [(18)F]FDG uptake.

Spinal cord compression by tophaceous gout with fluorodeoxyglucose-positron-emission tomographic/MR fusion imaging.

A 36-year-old woman presented with lower extremity paralysis. Her past medical history included gout. Conventional radiography and MR imaging revealed bone erosion and soft tissue lesions of the thoracic spine. Fluorodeoxyglucose-positron-emission tomographic (FDG-PET) images revealed hypermetabolic lesions of the thoracic spine. A CT-guided biopsy was diagnostic for inflammatory tophaceous gout. This case describes the CT, MR, and FDG-PET imaging characteristics of acute inflammatory gout. FDG-PET imaging characteristics of this disorder have not been previously described.

Epidural lipomatosis simulating an epidural abscess: case report and literature review.

A case of epidural lipomatosis in a 49-year-old man presenting with paraparesis, midthoracic pain, and Staphylococcus aureus pneumonia is reported. The patient had been on low dose corticosteroid therapy for 7 years for rheumatoid arthritis. The clinical and myelographic findings suggested a diagnosis of epidural abscess, but the only abnormality discovered at operation was abundant fatty tissue in the dorsal epidural space significantly compressing the spinal cord, and this was partially removed. Postoperative neurological improvement suggested that the lipomatosis was responsible for the spinal cord compression and dysfunction. If this diagnosis had been suspected, it might have been confirmed by magnetic resonance imaging or postmyelography computed tomographic scanning. With such a diagnosis, an alternative treatment could have been to decrease the steroid dose, observe for clinical improvement, and perhaps avoid operation.

Nasofrontal duct: CT in frontal sinus trauma.

Radiologic evaluation of frontal sinus fractures is instrumental in determining the need for surgery. Computed tomography (CT) is an excellent modality for evaluation of frontal sinus trauma, particularly for anterior and posterior wall fractures. However, fractures of the nasofrontal duct are more difficult to delineate, and judgments about operating for this problem are often made on less than concrete evidence of duct trauma. To evaluate the usefulness of CT in identifying nasofrontal duct trauma, a two-part study was done. First, CT was performed on cadavers to study the anatomic relationship of the nasofrontal duct to midface anatomy. Then, a retrospective study was performed in 19 patients with suspected frontal sinus fractures who underwent frontal sinus surgery. Findings at surgery were compared with preoperative evaluation with CT. Correlations were identified and criteria developed that can be used to identify patients needing surgical intervention in frontal sinus trauma. These criteria include findings of either a fracture involving the base of the frontal sinus or a fracture of the anterior ethmoid complex, or both.

Technique of stereotactic biopsy of two cranial target employing spherical coordinates to define a single trajectory.

A 'spherical coordinate system' has been developed to allow either stereotactic biopsy of two intracranial lesions using a single predetermined trajectory or biopsy of a single lesion through an existing burr hole. By means of the Gildenberg technique, the CT coordinates of the targets (or target and burr hole) are obtained. These are employed in three simple trigonometric equations to give three coordinates-two angles for the probe carrier (theta and alpha) and the radius (T) of a sphere, defined by one target as the center and the other target on the surface. These can be utilized in the Todd-Wells stereotactic frame. This system was evaluated using hollow skulls and crossed 30-gauge wire for phantom targets. The system was tried on ten different target combinations, and eight successful trajectories were obtained to within 3 mm. Two target combinations were inaccessible because of technical limitations of the Todd-Wells frame. This 'spherical coordinate system' can decrease the time to localize multiple targets as well as minimize the number of passes.

Traumatic atlanto-occipital dislocation. Case report.

Traumatic atlanto-occipital dislocation is a serious injury that is usually fatal. The number of patients surviving this injury, however, appears to be increasing, and most of these survivors are children. This may reflect an improvement in emergency transport services. Seventeen previously reported cases of patients surviving atlanto-occipital dislocation for more than 48 hours are reviewed and an additional case is presented. Many of these patients had an excellent neurological outcome. The radiographic criteria necessary for the diagnosis of atlanto-occipital dislocation are discussed. Cervical computerized tomography may confirm the diagnosis when necessary. It is suggested that there are three types of atlanto-occipital dislocation; utilizing this new classification, a rationale for treatment is described. Fusion is favored for long-term stability.

Gallium imaging of rheumatoid pachymeningitis.

A case of abnormal uptake of gallium in the tentorium cerebelli secondary to rheumatoid pachymeningitis is presented.

Polyvinyl alcohol foam-Gelfoam for therapeutic embolization: a synergistic mixture.

Gelfoam and polyvinyl alcohol foam particles each have advantages and disadvantages for therapeutic embolization. It was theorized and confirmed that a mixture of the two retains the advantages and eliminates the disadvantages of each. Two mixtures were prepared, tested in animals, and used successfully in 14 patients. It was found that the mixtures of Gelfoam and polyvinyl alcohol foam particles fulfilled the expectations and needs for particulate embolic materials.