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The authors present a patient with striking angiographic findings of systemic lupus erythematosus (SLE) cerebral vasculitis. Although lupus is often cited as part of the differential diagnosis for angiographically apparent cerebral vasculitis, true SLE cerebral vasculitis is rare in pathological and radiological series. The clinical spectrum and pathological findings of CNS lupus with particular attention to cerebral vasculitis are briefly discussed.

Prior to the advent of MR imaging, the internal architecture of the spinal cord could not be directly imaged. The solution of many technical problems (e.g., respiratory motion, cardiac and CSF pulsation, inadequate spatial resolution) has provided the opportunity for an increasingly refined analysis of intramedullary lesions. This article begins with a brief review of the results of high-resolution MR imaging studies of the cadaveric spinal cord. The article then focuses on MR imaging in the diagnosis of intramedullary diseases that involve specific neural pathways or vascular territories. Lesions are categorized as degenerative, inflammatory, traumatic, or ischemic. These diseases generally have distinctive clinical findings that reflect dysfunction of particular ascending sensory tracts or descending motor tracts. The corresponding abnormalities on MR images reflect the pathologic changes that occur in the affected neural pathways. Knowledge of the appearance of these diseases on MR images allows the formation of a narrow differential diagnosis and, in many cases, the confident exclusion of neoplasm as the cause of myelopathy.

A case of malignant optic glioma of adulthood is imaged in its early and late stages with high-resolution MR. The images show the mass to arise from the right optic nerve before invasion of the optic chiasm.

Purpose: To outline a quality assessment method with peer review for magnetic resonance (MR) imaging., Materials and Methods: Thirty-three providers in the Philadelphia area were rated on a random sample of 132 brain, 124 cervical spine, and 113 lower extremity MR imaging examinations performed during 1990. Blinded peer review was performed by panels of three subspecialty-trained academic radiologists. Technical performance, completeness, and report appropriateness of each MR imaging examination were evaluated. Aggregated scores were calculated to rate provider performance for each of the three parameters of quality., Results: Two or three panelists assessed technical performance as inadequate in 15 cases, completeness as incomplete in 58 cases, and the interpretative report as inappropriate and affecting treatment in 72 cases. Eleven providers received an unsatisfactory rating on one or more parameters of quality. The association between unsatisfactory ratings and the use of low-field-strength (< or = 0.6-T) imagers was statistically significant (P < .008)., Conclusion: Substantial deficiencies were identified in the performance of examinations and interpretation of MR images in the Philadelphia area in 1990. These findings indicate the need for a program to monitor quality of MR imaging.

Purpose: To determine the characteristic magnetic resonance (MR) imaging features of multiple sclerosis (MS) that affect the spinal cord., Materials and Methods: Sixty-eight patients underwent MR imaging of the cervical and/or thoracic spine. Plaques were analyzed for lesion length, cross-sectional area and location, signal intensity, and morphology. The clinical parameters of MS type, duration of disease, sex, and age were also correlated with these MR imaging findings., Results: One hundred twenty-four demyelinating plaques were found in these 68 patients; 38 had more than one plaque. The majority of plaques were two body segments in length or less and peripherally located, and occupied less than 50% of the cross-sectional area of the cord. Plaques associated with cord atrophy were more likely to occur with the relapsing-progressive form of MS. Cord swelling was found only in the relapsing-remitting form of MS., Conclusion: Spinal cord MS plaques are characteristically peripherally located, are less than two vertebral segments in length, and occupy less than half the cross-sectional area of the cord.

We describe a case of acute transverse myelitis after the administration of the recombinant form of hepatitis B vaccine. Abnormal enhancement of MR imaging accompanied residual neurologic deficit.

This article addresses imaging of intramedullary processes of the spinal cord. MRI, as the procedure of choice for the intramedullary space, is the primary imaging modality that is focused on. Patterns of signal abnormality, enhancement, and morphology are described that can be used to separate neoplasms, inflammation, infarction, vascular anomalies, degenerative processes, and congenital anomalies as they affect the spinal cord. Recognition of these patterns is essential for prompt and appropriate medical and surgical treatment.

This article emphasizes the utility of contrast-enhanced MRI in the detection of intradural extramedullary causes of myelopathy. Recognition of morphological patterns, signal intensities, and enhancement patterns frequently permits a specific diagnosis or a limited differential diagnosis.

MR appearance of two patients with large, orbital conjunctival epithelium-lined inclusion cysts are presented. Both were complications of ophthalmic surgical procedures that necessitated conjunctival incision.

Objective: Recent studies have shown that contrast (gadopentetate dimeglumine)-enhanced magnetic resonance imaging is useful in evaluating intraocular tumors and differentiating uveal melanoma from other simulating lesions. The purpose of this study was to study prospectively the role of fat-suppression technique and gadopentetate dimeglumine-enhanced magnetic resonance imaging in the evaluation of intraocular neoplasia., Patients: Forty-three uveal melanomas and 20 other simulating intraocular lesions from 63 patients were prospectively evaluated on non-contrast-enhanced and post-contrast-enhanced T1-weighted images with and without fat-suppression technique and on T2-weighted images., Results: Forty-one uveal melanomas (95%) were detected with standard pulse sequences and showed the characteristic hyperintense signal on non-contrast-enhanced T1-weighted images and hypointense signal with respect to the vitreous on T2-weighted images. All 33 uveal melanomas evaluated on non-contrast-enhanced T1-weighted images with fat-suppression technique were detected on non-contrast-enhanced images with fat-suppression technique. The intensity of the signal was statistically associated with the degree of pigmentation of the tumor on T1-weighted images with fat-suppression technique (P = .03). On post-contrast-enhanced T1-weighted images with or without fat-suppression technique, the 43 uveal melanomas showed enhancement. The degree of tumor enhancement was not statistically related to the degree of tumor pigmentation or the location of the tumor. Among the other simulating intraocular lesions, choroidal metastasis, retinoblastoma, choroidal leiomyoma, and medulloepithelioma demonstrated the same features on magnetic resonance imaging studies as uveal melanoma demonstrated on non-contrast-enhanced and post-contrast-enhanced T1-weighted images with or without fat-suppression technique. In our series, choroidal hemangioma, choroidal osteoma, posterior scleritis, retinal hemangioma, and Coats' disease can be differentiated from other amelanotic intraocular tumors by their characteristics on magnetic resonance imaging studies., Conclusions: We concluded that pre-and post-contrast-enhanced T1-weighted images with fat-suppression technique are most helpful in detecting small intraocular tumors with a thickness of more than 1.8 mm and in evaluating intraocular neoplasms and simulating lesions, particularly when T2-weighted images are not available. Moreover, in juxtapapillary choroidal or retinal tumor, fat-suppression technique may help in the detection of possible optic nerve or orbital extension by improving the conspicuousness of the tumor.

This essay illustrates the imaging spectrum of vascular neoplasms and malformations, ischemia, and hemorrhage affecting the spinal cord. Most of these abnormalities occur far more frequently in the brain. The goal of this essay is to provide a sound anatomic and radiologic basis for the evaluation of these diseases. Knowledge of the unique cross-sectional anatomy, blood supply, and venous drainage of the spinal cord is essential in understanding the radiographic appearance of certain vascular lesions. The superior spatial resolution of fast spin-echo pulse sequences and improvements in MR angiography have expanded the role of MR imaging in the diagnosis of spinal cord diseases. These techniques are emphasized in this essay, and potential diagnostic pitfalls are highlighted. The diseases illustrated are grouped in the categories of enlarged vessels, ischemia, and hemorrhage.

Purpose: To determine whether the relative insensitivity of T2-weighted fast spin-echo (FSE) techniques to magnetic susceptibility can be exploited to reduce metallic artifacts on images of the postoperative spine and, thus, improve the interpretation of the postoperative study., Materials and Methods: Three neuroradiologists retrospectively evaluated sagittal T2-weighted conventional spin-echo and FSE images obtained in 15 patients with metallic artifacts from various sources including drill particles from anterior cervical diskectomy, posterior fixation wires, fixation rods or plates, and an inferior vena cava filter. The amount of artifact present and whether these artifacts affected image interpretation were evaluated., Results: Among the 45 paired evaluations, the artifact was judged to be less apparent with FSE sequences in 39. In eight of 45 evaluations (18%), the interpretation of the area of interest was possible only on the FSE images., Conclusion: FSE imaging, especially when performed with shorter echo spacing, increases the amount of T2-weighted information in the presence of metallic artifact because it decreases magnetic susceptibility effects.

Production of melatonin, a hormone synthesized and secreted by the pineal body, has been suppressed by electromagnetic fields in some but not all animal studies. Magnetic resonance (MR) imaging at 1.5 T was evaluated for its ability to modulate the level of melatonin in eight male volunteers. Subjects were exposed to three conditions, respectively, between 1:00 and 2:00 AM on different nights: (a) a series of routine MR pulse sequences for brain imaging in dark conditions, (b) dark control conditions, and (c) bright-light control conditions. Plasma was analyzed for melatonin and cortisol levels. Hormonal changes were analyzed by one-factor repeated measures within-subject analysis of variance. These conditions were associated with significant differences in melatonin levels: F(2, 6) = 7.95, and P = .021. Subjects exposed to darkness showed a typical increase in melatonin concentration. Subjects exposed to bright light showed a characteristic suppression of melatonin concentration. Those exposed to the MR imaging fields showed an increase in melatonin level similar to that seen in the dark control condition. Light and MR imaging had no significant effects on cortisol levels. Thus, MR imaging at field strengths known to modulate melatonin levels in rats did not suppress melatonin production in human subjects.

Cerebral venous outflow obstruction and anomalies in cerebral venous circulation predispose to dural sinus thrombosis. This case report illustrates the magnetic resonance and angiographic findings in a patient who had superior sagittal sinus thrombosis secondary to idiopathic bilateral internal jugular vein stenosis, a previously unrecognized entity. The findings suggest that bilateral stenosis of the internal jugular veins at their junction with the innominate veins causes obstruction to cerebral venous outflow leading to dural sinus thrombosis.

While Modic has described certain MRI changes in bone grafts in patients after anterior cervical discectomy and fusion (ACF), no study has evaluated specific MRI signal changes in the fusion mass prospectively and longitudinally. The goal of the present study was to prospectively evaluate MRI changes in ACF grafts in a longitudinal fashion. Twenty-seven MRIs were included in the evaluation of seven postoperative patients. MRIs were obtained in a 1.5 tesla GE imager immediately postoperatively, and at 1, 3, and 6 months in most patients. All patients received at least three sequential MRIs. Two patients had greater than one level fused. T1 and T2 images were evaluated in all patients at each available interval. GRASS images were not found to be helpful secondary to a prohibitive amount of noise. For single level fusion masses, T1 images showed a very intense homogeneous graft signal in the immediate postoperative period which decreased slightly at 1 month. At 3 months the signal intensity of the graft was similar to the 1 month image, but was slightly less homogeneous. At 6 months, the T1 signal had greatly decreased in much of the graft. Immediate postoperative specimens showed heterogeneously high signal on T2 images which increased at 1 month in the whole graft, and then seemed to increase at the endplates while decreasing in the graft at 3 months. At 6 months the graft was becoming difficult to delineate on T2 images in many specimens. The two and three level fusions had a more heterogeneous image progression without clear evidence of solid fusion at 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose of this study was to examine the relationship between the initial intramedullary hemorrhage, as seen by magnetic resonance imaging (MRI), and the neurologic deficit and eventual neurologic outcome of acute cervical spinal cord injured subjects. MRI and motor assessments were performed on 24 subjects with motor complete (Frankel A & B) and incomplete (Frankel C & D) injuries. Recovery was determined by evaluating an initial and a final motor power following spinal cord injury (SCI), as defined by the manual muscle test (grade 1-5) and motor index score (MIS). Results showed that all 15 subjects having hemorrhage had motor complete injuries (Frankel A & B). Sixteen percent of the muscles in the upper extremities and 3% of the muscles in the lower extremities in these 15 subjects improved to a grade of > or = 3/5 at the final evaluation post-SCI. In comparison, of the nine subjects not having hemorrhage, eight had motor incomplete injuries (Frankel C & D) and had 73% and 74% of muscles improving in the upper and lower extremities, respectively. In addition, a change in MIS from initial to final evaluations showed a significant difference between subjects with hemorrhage and subjects without hemorrhage (upper extremities: p = .002 and lower extremities: p = .0001). In conclusion, the initial MR image and neurologic assessment correlated with motor power recovery.

Purpose: To evaluate the safety and efficacy of gadoteridol as an MR contrast agent in patients with suspected head and neck pathology., Methods: One hundred thirty-three adult patients were studied with MR at 12 clinical trial sites before and after the intravenous administration of 0.10 mmol/kg gadoteridol. After enrollment, patients underwent a complete physical examination. Patient monitoring included vital signs, laboratory tests, and recording of the incidence and duration of adverse events. To evaluate efficacy, postcontrast T1-weighted images were compared with precontrast T1- and T2-weighted images. Investigators having clinical information evaluated 129 studies for efficacy; two readers blinded to clinical information subsequently evaluated 122 studies using the same criteria as the investigators., Results: Eight patients (6.0%) experienced mild adverse events possibly or probably related to contrast administration, all of which resolved without treatment. Two clinically significant laboratory abnormalities considered related or possibly related to the administration of gadoteridol were reported in two patients. Enhancement of pathology was seen in 82.9% of cases evaluated by investigators at the study site and in 78.7% of cases subsequently evaluated by the blinded readers. Postcontrast images were judged by investigators to provide additional diagnostic information over precontrast images in 68.9% of studies. The additional diagnostic information available on postcontrast studies most often consisted of improved visualization of pathology and better definition of lesion borders. The use of this information might have contributed to a change in patient diagnosis in 18.6% of the cases evaluated by the investigators and in 16.4% of the cases reviewed by the blinded readers., Conclusions: Preliminary results show gadoteridol to be a safe and efficacious contrast agent for enhanced MR study of extracranial and extraspinal head and neck pathology.

Magnetic resonance imaging is frequently complicated by the presence of motion and susceptibility gradients. Also, some biologic tissues have short T2s. These problems are particularly troublesome in fast spin-echo (FSE) imaging, in which T2 decay and motion between echoes result in image blurring and ghost artifacts. The authors reduced TE in conventional spin-echo (SE) imaging to 5 msec and echo spacing (E-space) in FSE imaging to 6 msec. All magnetic gradients (except readout) were kept at a maximum, with data sampling as fast as 125 kHz and only ramp waveforms used. Truncated sinc radio-frequency pulses and asymmetric echo sampling were also used in SE imaging. Short TE (5.8 msec) SE images of the upper abdomen were compared with conventional SE images (TE = 11 msec). Also, FSE images with short E-space were compared with conventional FSE images in multiple body sites. Short TE significantly improved the liver-spleen contrast-to-total noise ratio (C/N) (7.9 vs 4.1, n = 9, P < .01) on T1-weighted SE images, reduced the intensity of ghost artifacts (by 34%, P < .02), and increased the number of available imaging planes by 30%. It also improved delineation of cranial nerves and reduced susceptibility artifacts. On short E-space FSE images, spine, lung, upper abdomen, and musculoskeletal tissues appeared crisper and measured spleen-liver C/N increased significantly (6.9 vs 4.0, n = 12, P < .01). The delineation of tissues with short T2 (eg, cartilage) and motion artifact suppression were also improved. Short TE methods can improve image quality in both SE and FSE imaging and merit further clinical evaluation.

Few detailed radiologic articles treat the medial canthus as a "compartment" of the orbit. Nasal stuffiness and epiphora (excessive tearing) are frequent clinical manifestations of diseases involving the medial canthus of the orbit. Although some lesions can be adequately evaluated by clinical examination, imaging may show unsuspected deep extensions of the abnormality. CT has traditionally been the imaging method of choice because of the inherent contrast between structures in this region and its superb depiction of bone detail (Fig. 1). MR imaging can be useful in detecting subtle marrow invasion caused by lesions extending beyond the confines of the medial canthus (e.g., frontal bone, maxilla). In this pictorial essay, we illustrate the CT and MR appearances of diseases that can manifest as a medial canthal mass and provide practical differential diagnoses. Lesions can be inflammatory, neoplastic, or developmental in origin. Moreover, these lesions can result from abnormalities in the adjacent nasolacrimal apparatus, orbit, paranasal sinuses, and nasal cavity, or they can reflect an underlying systemic illness.

Intradural extramedullary schwannomas are nerve sheath neoplasms that consist of focal proliferations of Schwann cells involving a spinal nerve. We reviewed the MR findings in seven patients with pathologically proved intradural schwannomas. The contrast-enhancement characteristics on MR images were determined and compared with the histologic features of the tumor. Six lesions were variably hyperintense on T2-weighted images and one was uniformly hypointense compared with the signal intensity of the spinal cord. Signal on T1-weighted images ranged from hypointense to isointense. All seven tumors showed heterogeneous enhancement; in five, the enhancement involved only the periphery of the lesion. The pattern of enhancement did not correlate with the signal characteristics noted on unenhanced T1- and T2-weighted images. Pathologically, hyaline thickening of vessel walls and cyst formation were prevalent in the peripherally enhancing lesions. However, enhancement did not correlate with the relative proportion of Antoni type A and type B tissue. Recognition of the MR characteristics of intradural extramedullary schwannomas may be helpful in the differential diagnosis of spinal tumors. In particular, peripheral contrast enhancement of an intradural extramedullary tumor on MR images should suggest the diagnosis of schwannoma.

The role of magnetic resonance imaging (MRI) in the assessment of fibrovascular ingrowth in the integrated hydroxyapatite orbital implant is evaluated. Fifteen patients who underwent enucleation and placement of a hydroxyapatite orbital implant were evaluated for degree of implant vascularity with gadolinium-DPTA-enhanced MRI with surface coil before drilling the implant. On T1-weighted images, the hydroxyapatite sphere appeared with intermediate signal. After gadolinium-DPTA administration, all patients showed an enhancement in the implant consistent with the presence of fibrovascular ingrowth. The enhancement was most notable in the peripheral portions of the sphere and was seen as early as 5 months after implantation. Comparison of gadolinium-DPTA-enhanced MRI with contrast-enhanced computed tomography, ultrasonography, and color Doppler imaging suggests that these latter techniques are not as helpful in the detection of the fibrovascular tissue in the orbital implant. Bone scan, a technique used by many surgeons, demonstrates fibrovascular ingrowth, but it is limited by its one-dimensional low-resolution image. Because of its three-dimensional capability and its highest resolution, contrast-enhanced MRI with surface coil appears to be the best imaging method for evaluating the hydroxyapatite orbital implant and its fibrovascular ingrowth.

Fifty-seven patients with acute cervical spine injuries and associated major neurological deficit were examined within 2 weeks of injury by magnetic resonance (MR) imaging. All patients had abnormal scans, indicating intramedullary lesions. This study was undertaken to determine if the early MR imaging pattern had a prognostic relationship to the eventual neurological outcome. Three different MR imaging patterns were observed in these patients: 21 patients had patterns characteristic of intramedullary hematoma (Group 1); 17 had intramedullary edema over more than one spinal segment, but no hemorrhage (Group 2); and 19 had restricted zones of intramedullary edema involving one spinal segment or less (Group 3). The neurological state was determined using standard motor index scores at admission and at follow-up examination. Characteristically, the patients in Group 1 had admission motor scores significantly lower than the other two groups. At follow-up examination, the median percent motor recovery was 9% for Group 1, 41% for Group 2, and 72% for Group 3. These studies suggest that the MR imaging pattern observed in the acutely injured human spinal cord has a prognostic significance in the final outcome of the motor system. It is only when an accurate prognosis can be given at the outset that useful treatment data might be collected for homogeneous injury groups, and accurately based long-term planning made for the best patient care.

We report three cases that reveal an array of etiologic and radiologic findings associated with dissection of the proximal segment of the vertebral arteries. Regardless of etiology, the proximal segment may be the principal site of dissection in these vessels.

In this phase III study, 411 adult patients with suspected intracranial or spinal disease underwent magnetic resonance (MR) imaging before and after intravenous injection of 0.1 mmol/kg gadoteridol (gadolinium 1,4,7-tris [carboxymethyl]-10-[2'-hydroxypropyl]-1,4,7,10-tetraazacyclododecane+ ++). MR images were evaluated by a single unblinded reader at each of 27 sites; the diagnosis was confirmed with one of nine imaging or surgical procedures within 8 weeks before or after MR imaging. After injection, no clinically significant changes were noted in laboratory values, physical examination, or vital signs. Adverse clinical events possibly or probably associated with injection of gadoteridol were seen in 18 of 411 patients (4.4%); the most common were dysgeusia and mild nausea, and all abated without residual effects. MR images enhanced with gadoteridol in patients with confirmed disease provided more diagnostic information than unenhanced images in 128 of 175 brain examinations (73.1%) and 93 of 137 spinal examinations (67.9%). A change in diagnosis because of additional information from contrast-enhanced images was considered likely in 63 of 214 cranial and 54 of 161 spinal studies.

We retrospectively reviewed the routine spin-echo MR studies of the brain in 12 patients with 13 angiographically demonstrated occlusions and in 14 patients with 16 high-grade stenoses of the carotid arteries. Intraluminal signal that was isointense with adjacent brain on long TR/short TE and long TR/long TE images was 100% specific for atherosclerotic occlusion. Of the 13 proved occlusions, six (46%) had significant degrees of hyperintense intraluminal signal indistinguishable from that observed consequent to slow flow distal to high-grade stenoses. MR detected only five (31%) of the 16 proved high-grade stenoses. Normal flow void does not exclude significant extracranial carotid stenosis. Occlusion cannot always be distinguished from high-grade stenosis when hyperintense intraluminal signal is encountered. However, a reliable diagnosis of atherosclerotic occlusion can be made when isointense intraluminal signal is observed.

The present study was conducted to evaluate the imaging capabilities of magnetic resonance imaging (MRI) in evaluating acute cervical spinal column injury and compare these results to that of computed tomographic (CT) imaging. Forty-nine patients undergoing MRI at a Level I and regional spinal cord trauma center to evaluate cervical spinal column injury were studied. Seventy-one injuries were identified by MRI. These injuries were classified as osseous (fracture/dislocation) (n = 21), disc herniation (n = 29), and spinal cord injury (edema/contusion/transection) (n = 21). Diagnostic imaging results in 33 of the 49 patients undergoing both MRI and CT were compared. CT demonstrated 22 fracture/dislocations compared to 10 on MRI. MRI demonstrated 19 disc protrusions compared to 7 on CT. Additionally, MR imaged 13 cord injuries as compared to 0 by CT. MR imaging proved superior in demonstrating spinal cord pathology and intervertebral disc herniation. CT was superior to MRI in demonstrating osseous injury. CT and MRI may be useful together in determining presence and extent of spinal column injury.

A retrospective analysis of magnetic resonance (MR) imaging studies of 78 patients with acute cervical spinal cord injuries was undertaken to determine which observations related directly to the neurologic injury. All MR imaging studies were performed on a 1.5-T unit and assessed with respect to 14 parameters related to the bony spine, ligaments, prevertebral soft tissues, intervertebral disks, and spinal cord. Forty-eight patients also underwent non-contrast material-enhanced thin-section computed tomography (CT) of the cervical spine. MR imaging was the definitive modality in the assessment of soft-tissue injury, especially in the evaluation of the spinal cord and intervertebral disks. All patients with a neurologic deficit had abnormal spinal cords at MR imaging. Intramedullary hemorrhage was predictive of a complete lesion. The degree of associated bone and soft-tissue injury had no bearing on the extent of spinal cord injury or neurologic deficit. Patients with residual cord compression following reduction demonstrated greater neurologic compromise than those without compression.

CT and MRI have made it possible to make a strongly presumptive diagnosis of orbital lymphoid tumors. Orbital lymphomas are usually homogeneous masses of relatively high density and sharp margins. The lesions mold themselves to pre-existing structures without eroding the bone. On MR imaging, they appear as relatively hypointense images, particularly in T1-weighted MR scans.

Diagnosis of retinoblastoma is one of the most challenging problems of pediatric ophthalmology and radiology. It must be differentiated from numerous simulating lesions. Accurate diagnosis by means of ultrasonography, CT, and MR is essential for prompt treatment and prevention of metastasis. The CT and MR findings in 45 patients are presented in this article in order to evaluate and compare the usefulness of these two imaging techniques in the diagnosis of retinoblastoma.

The classic MR appearance of paranasal sinus mucoceles is due to its cystic composition. We present two cases of paranasal sinus mucocele that exhibit atypical signal characteristics. The morphology of this lesion, rather than its signal intensity, is paramount in establishing this diagnosis.

Orbital pseudotumor is a nonspecific inflammatory process of unknown etiology that may mimic a true orbital neoplasm, specifically lymphoma. It exhibits a highly variable clinical and radiographic presentation. Thirty-nine patients with a presumptive diagnosis of orbital inflammatory disease were examined with CT and evaluated with respect to 13 findings associated with inflammatory disease of the orbit. Pseudotumor was included as part of the differential diagnosis in 25 patients. Twenty-one cases received a final (clinical) diagnosis of pseudotumor. The remainder were comprised of a broad range of orbital inflammatory conditions. Key radiographic features required to entertain or exclude the diagnosis of pseudotumor included establishing the presence of an orbital mass, extraocular muscle enlargement, bony erosion, enhancement, and associated paranasal sinus disease.