Definition of the supraclavicular and infraclavicular nodes: implications for three-dimensional CT-based conformal radiation therapy.

PURPOSE: To delineate with computed tomography (CT) the anatomic regions containing the supraclavicular (SCV) and infraclavicular (IFV) nodal groups, to define the course of the brachial plexus, to estimate the actual radiation dose received by these regions in a series of patients treated in the traditional manner, and to compare these doses to those received with an optimized dosimetric technique. MATERIALS AND METHODS: Twenty patients underwent contrast material-enhanced CT for the purpose of radiation therapy planning. CT scans were used to study the location of the SCV and IFV nodal regions by using outlining of readily identifiable anatomic structures that define the nodal groups. The brachial plexus was also outlined by using similar methods. Radiation therapy doses to the SCV and IFV were then estimated by using traditional dose calculations and optimized planning. A repeated measures analysis of covariance was used to compare the SCV and IFV depths and to compare the doses achieved with the traditional and optimized methods. RESULTS: Coverage by the 90% isodose surface was significantly decreased with traditional planning versus conformal planning as the depth to the SCV nodes increased (P < .001). Significantly decreased coverage by using the 90% isodose surface was demonstrated for traditional planning versus conformal planning with increasing IFV depth (P = .015). A linear correlation was found between brachial plexus depth and SCV depth up to 7 cm. CONCLUSION: Conformal optimized planning provided improved dosimetric coverage compared with standard techniques.

Identification and characterization of SKAT-2, a novel Th2-specific zinc finger gene.

We have identified a novel Kruppel-type zinc finger (ZF) gene, SKAT-2, which is selectively expressed by murine Th2 cells. The protein encoded by this gene has 14 C2H2-type ZF tandemly arrayed at its C terminus and N-terminal SCAN box and KRAB domains. SKAT-2 is tissue restricted in expression at the RNA level, detectable only in brain and at low levels in kidney and spleen and few hematopoietic cell lines. By in situ hybridization, SKAT-2 expression was found to peak in antigen-stimulated CD4(+) T cells after 2-3 days of culture under Th2 but not Th1 biasing conditions. This pattern of expression closely mirrored that of GATA-3 in the same cells. In transient transfection experiments in phorbol 12-myristate 13-acetate/ionomycin-stimulated EL4 cells, SKAT-2 was found to up-regulate the activity of the IL-4 but not the IL-5 promoter, contrasting with the ability of GATA-3 to activate both promoters. This result was confirmed using clones of EL4 cells stably expressing an inducible form of SKAT-2, thus SKAT-2 is a novel Th2-specific gene that may play a role in selective regulation of cytokine genes in T cells.

The persistent stapedial artery.

The persistent stapedial artery is a rare congenital vascular anomaly that may present as a pulsatile middle ear mass or that may appear as an incidental finding. Five cases of persistent stapedial artery are presented. The CT findings include the absence of the ipsilateral foramen spinosum and a soft-tissue prominence in the region of the tympanic segment of the facial nerve. Three cases were associated with an aberrant internal carotid artery. Imaging identification of this variant may obviate unnecessary surgery and may help in planning surgical or endovascular interventions.

Extracranial metastatic meningioma.

Meningiomas rarely metastasize outside the intracranial compartment. We report a case of disseminated metastases from a recurrent intracranial meningioma and review the imaging and pathological literature on metastatic meningioma.

Emergency magnetic resonance imaging of cervical spinal cord injuries: clinical correlation and prognosis.

OBJECTIVE: The goal of this study was to determine the prognostic and clinical value of magnetic resonance imaging (MRI) performed within hours after cervical spinal cord injuries in human patients. METHODS: Fifty-five patients with acute cervical vertebral column and spinal cord injuries underwent MRI as part of their initial treatment at the University of Michigan Medical Center. All images were obtained within 21 hours after injury (mean, 7.8 h) and were interpreted by an attending neuroradiologist who was blinded to the clinical status of the patients. Neurological function at presentation and in long-term follow-up examinations was compared with MRI characteristics assessed immediately after the injury. RESULTS: The presence and rostrocaudal length of intra-axial hematoma, the rostrocaudal length of spinal cord edema, the presence of spinal cord compression, and spinal cord compression by extra-axial hematoma were each significantly associated with poor neurological function at presentation and in long-term follow-up examinations. Although the best single predictor of long-term improvement in neurological function was the neurological function at presentation, four MRI characteristics, i.e., the presence of intra-axial hematoma, the extent of spinal cord hematoma, the extent of spinal cord edema, and spinal cord compression by extra-axial hematoma, provided significant additional prognostic information. MRI data demonstrated spinal cord compression for 27 of 55 patients (49%), leading to emergency surgery. Among patients who underwent imaging after restoration of normal vertebral alignment using closed cervical traction, 13 of 26 (50%) underwent emergency surgery for treatment of persistent, MRI-demonstrated, spinal cord compression. CONCLUSION: Emergency MRI after spinal cord injury provides accurate prognostic information regarding neurological function and aids in the diagnosis and treatment of persistent spinal cord compression after vertebral realignment.

Computer-assisted measurement of lumbar spine radiographs.

RATIONALE AND OBJECTIVES: The authors evaluated a method for obtaining reproducible, reliable measurements from standard lumbar spine radiographs for determining the degree of spondylolisthesis, vertebral body height, intervertebral disk space height, disk space angle, and degree of vertebral body wedging. MATERIALS AND METHODS: Four to six easily defined points were identified on each vertebral body on anteroposterior and lateral plain radiographs of the lumbosacral spine of patients. From these points, the degree of spondylolisthesis, the vertebral body height, the intervertebral disk space height, the disk space angle, and the degree of vertebral body wedging were easily calculated by using well-known geometric relationships. This method requires the use of a personal computer and a standard spreadsheet program but does not require the use of any other specialized radiographic equipment, computer hardware, or custom software. RESULTS: Calculations of intra- and interobserver variability for the measurement of spondylolisthesis, disk space height, disk space angle, and vertebral body height measurement showed that the technique is extremely reproducible. CONCLUSION: This technique may prove useful in the prospective evaluation of potential candidates for lumbar spinal stenosis surgery.

CT-guided brachial plexus biopsy.

We describe a technique for conducting a CT-guided biopsy of the brachial plexus region, report two illustrative cases, discuss potential complications, and conclude that, in selected cases, biopsy of lesions in the region of the brachial plexus can be performed safely with CT guidance.

MRI of optic nerve enlargement in optic neuritis.

We report two cases of optic neuritis with optic nerve enlargement on MRI. Both had a clinical course typical for optic neuritis but also had a neuroradiologic finding most commonly seen with optic nerve glioma or meningioma, which initially led to an incorrect diagnosis. We review the six previous reported cases of optic nerve enlargement in optic neuritis. Including our cases, six of eight reported cases were in children with severe initial visual loss. Optic nerve enlargement is a rare finding in optic neuritis that might be a subtype of optic neuritis.

CT demonstration of periorbital graft-versus-host disease.

A 13-year-old boy who had undergone allogenic bone marrow transplantation for treatment of acute lymphocytic leukemia presented with bilateral periorbital rash and swelling. A CT scan showed bilateral symmetric periorbital swelling, subconjunctival fluid collections, and lacrimal gland enlargement. The patient was initially treated for presumed cellulitis. However, persistently negative regional cultures (eye, nasopharynx), a rapid response to immunosuppressive therapy after several days of nonresponse to intravenous antibiotic therapy, and ultimately, results of a skin biopsy confirmed the diagnosis of acute graft-versus-host disease.

Unusual tumours of the skull and skull base: a pictorial essay.

Six unusual tumours of the skull and skull base are illustrated in this pictorial essay; for three of the tumours, both magnetic resonance imaging and computed tomography were performed preoperatively. These two imaging modalities can provide complementary information in the preoperative evaluation of unusual tumours of the skull and skull base.

Intracranial gas: a pictorial essay.

Intracranial gas is a common finding on postcraniotomy computed tomography scans. It can also be found in a wide variety of other benign and life-threatening clinical settings. Because intracranial gas is never normal, its presence must be explained. This pictorial essay describes the imaging features of intracranial gas and demonstrates the findings for many of the causes of this condition.

Pre- and postoperative MR imaging of craniopharyngiomas.

PURPOSE: To compare the pre- and postoperative MR appearance of craniopharyngiomas with respect to lesion size, tumour morphology and identification of surrounding normal structures. MATERIAL AND METHODS: MR images obtained prior to and following craniopharyngioma resection were evaluated retrospectively in 10 patients. Tumour signal characteristics, size and extension with particular reference to the optic chiasm, the pituitary gland, the pituitary stalk and the third ventricle were evaluated. RESULTS: Following surgery, tumour volume was reduced in all patients. In 6 patients there was further tumour volume reduction between the first and second postoperative images. Two of these patients received radiation therapy between the 2 postoperative studies, while 4 had no adjuvant treatment to the surgical intervention. There was improved visualization of the optic chiasm in 3, the pituitary stalk in one, and the third ventricle in 9 of the 10 patients. The pituitary gland was identified preoperatively only in one patient, postoperatively only in another, pre- and postoperatively in 5, and neither pre- nor postoperatively in 3 patients. In 3 patients MR imaging 0-7 days postoperatively identified tumour remnants not seen at the end of the surgical procedure. The signal intensities of solid and cystic tumour components were stable from pre- to the first postoperative MR images. Optic tract increased signal prior to surgery was gone 28 days postoperatively in one patient, but persisted on the left side for 197 days after surgery in another. CONCLUSION: Postoperative MR imaging of craniopharyngiomas demonstrated tumour volume reduction and tumour remnants not seen at surgery. Early postoperative MR imaging of craniopharyngiomas may overestimate the size of residual tumour. Improved visualization of peritumoral structures may be achieved.

Recurrence of head and neck cancer after surgery or irradiation: prospective comparison of 2-deoxy-2-[F-18]fluoro-D-glucose PET and MR imaging diagnoses.

PURPOSE: To evaluate the diagnostic accuracy of positron emission tomography (PET) with administration of 2-deoxy-2-[fluorine-18]fluoro-D-glucose (FDG) relative to that of magnetic resonance (MR) imaging and/or computed tomography (CT) in recurrent head and neck cancers. MATERIALS AND METHODS: Twelve adult patients (mean age, 63 years) with previously treated head and neck cancers and clinical suspicion of recurrence underwent FDG PET and MR imaging and/or CT. All images were blindly and independently interpreted without histopathologic findings (obtained within 1 week of imaging). The level of confidence in image interpretation was graded by using a five-point rating system (0 = definitely no recurrence to 4 = definite recurrence). RESULTS: Recurrence was confirmed in eight patients. With a rating of 4 as a positive finding, FDG PET yielded a sensitivity and specificity of 88% (seven of eight) and 100% (four of four), respectively; MR imaging and/or CT, 25% (two of eight) and 75% (three of four), respectively. Receiver-operating characteristic analysis showed significantly better diagnostic accuracy with FDG PET than with MR imaging and/or CT (area under curve = 0.96 vs 0.55, P < .03). CONCLUSION: These data indicate that PET metabolic imaging, as compared with anatomic methods, has improved diagnostic accuracy for recurrent head and neck cancer.

Magnetic resonance imaging of normal meningeal enhancement at 1.5 T.

RATIONALE AND OBJECTIVES: We examined patterns of intracranial meningeal enhancement on gadolinium chelate contrast media-enhanced 1.5-T spin-echo magnetic resonance (MR) imaging and developed criteria that might be useful for distinguishing between normal and abnormal meningeal enhancement. METHODS: The convexity, falx cerebri, tentorium cerebelli, and suprasellar cistern regions of 204 patients were prospectively evaluated for contrast enhancement with a grading system ranging from 0 (no enhancement) to 5 (diffuse, irregular, thickened enhancement). Meningeal findings were correlated with other MR abnormalities and pertinent clinical histories that have been associated previously with meningeal enhancement. RESULTS: Short-segment convexity meningeal enhancement was commonly seen and most likely represents intravascular contrast material in normal meningeal vessels. Such enhancement did not correlate with the presence of other MR abnormalities. Long-segment (> 3 cm) or diffuse convexity meningeal enhancement did correlate with other significant MR abnormalities and pertinent clinical history. Fine linear falcine and tentorial meningeal enhancement, as an isolated finding, did not correlate with other MR or clinical abnormalities. The suprasellar cistern and ventricular walls were rarely enhanced. CONCLUSION: Short-segment convexity meningeal contrast enhancement is a normal finding representing normal vascular structures. More extensive convexity meningeal enhancement is abnormal and should prompt careful examination of the remainder of an MR image as well as the patient's clinical history for an etiology of the enhancement.

MR of myelomatous meningitis.

In a 56-year-old woman with multiple myeloma involving the leptomeninges diffusely, MR of the spine showed multiple vertebral compression fractures and marked enhancement of the cauda equina region. Intracranial MR showed pathologic enhancement of the left third and fifth cranial nerves.

Primary osseous amyloidoma causing spinal cord compression.

The myelographic, CT, and MR findings of a rare localized primary bone amyloidoma causing upper thoracic spinal cord compression are presented. Imaging showed a large, calcified mass centered in the posteromedial portion of the left second rib that invaded the second thoracic vertebra and the spinal canal.