Osteoid osteoma and osteoblastoma: MRI appearances and the significance of ring enhancement.

We assessed the value of contrast-enhanced fat-suppressed MRI on nine patients with osteoid osteomas and osteoblastomas. The results were compared with plain films, bone scintigraphy, computed tomography (CT) and pathological specimens. On contrast-enhanced fat-suppressed T1-weighted images the non-calcified nidi showed homogeneous enhancement, whereas the calcified lesions showed a ring enhancement sign that was proportional in intensity to the extent of the remaining part of the vascularized nidus. The degree of bone marrow and soft tissue enhancement was relative to the size and reactive inflammatory changes of the lesions. Although CT was diagnostic in most of the cases and more specific to show the calcified lesions, MRI was confirmatory in one case. We concluded that, although CT is the primary diagnostic investigation in osteoid osteomas, MRI can be reserved for equivocal cases.

Role of CT and MR imaging in the management of tuberculous spondylitis.

Tuberculous spondylitis is an infection involving one or more of the components of the spine, namely the vertebral body, intervertebral disc and ligaments, paravertebral soft tissues, and the epidural space. The causative organism belongs to one of the different strains of Mycobacterium tuberculosis. The role of CT and MR imaging in the diagnosis and management of tuberculous spondylitis is reviewed, and the differential diagnosis of these appearances is discussed. The possible impact of HIV infection on the number of reported cases and their mode of presentation also is considered. The need for prompt diagnosis is emphasized.

Making global telemedicine practical and affordable: demonstrations from the Middle East.

OBJECTIVE: The purpose of this study was to demonstrate the first use of voice-grade telephone lines for the international transmission of both high-resolution digital images (radiology and pathology) and video in near real-time. MATERIALS AND METHODS: Eight live demonstrations were performed from the United Arab Emirates and the Kingdom of Saudi Arabia at the invitation of the respective ministries of health. Thirty radiologic studies (CT, MR, and radiographs) were digitized, compressed, and transmitted to Cambridge, MA, where they were interpreted on diagnostic workstations (1792 x 2252 display matrix) by a team of subspecialist radiologists. Near real-time image transmission was achieved by combining wavelet-based image compression (average compression ratio of 23:1) and multiplexing technology that used four phone lines simultaneously. During each demonstration, one pathology image was transmitted from Cambridge to the demonstration site, where it was interpreted by a visiting pathologist. Video-conferencing was implemented with a 64-kilobits-per-sec leased line from the United Arab Emirates and with four multiplexed telephone lines from Saudi Arabia. RESULTS: For teleradiology and telepathology, transmission times ranged from 2-5 min per image. Image fidelity was judged to be of diagnostic quality in all transmitted cases. The video link to the United Arab Emirates was highly reliable. Bandwidth for videoconferencing from Saudi Arabia was marginal on four voice-grade telephone lines, resulting in some downtime (10-20%). Live consultations provided by subspecialists in Cambridge assisted in the management of patients at both venues. The system was well received by both the referring physicians in the Middle East and the participants in the United States. CONCLUSION: Image compression and multiplexing technologies enabled high-resolution teleradiology and telepathology as well as real-time video consultations over international telephone lines. While telecommunications systems are advancing rapidly in many parts of the world, those areas most in need of telemedicine services are likely to be the last to upgrade their telecommunications infrastructures. This "proof of concept" article outlines a practical and affordable approach that makes telemedicine more accessible to underserved areas worldwide.

Imaging features of musculoskeletal brucellosis.

Brucellosis is endemic in certain parts of the world. Musculoskeletal involvement is the most common complication of brucellosis, and the spine is most frequently affected. Between November 1985 and March 1993, 334 patients with radiologically proved musculoskeletal brucellosis were seen. Involvement of the spine was either focal or diffuse, with a predilection to the lumbar region. Erosions and sclerosis in vertebral end plates, changes of inflammation at scintigraphy or magnetic resonance (MR) imaging, and intact disks were hallmarks of the focal form. Osteomyelitis of neighboring vertebrae, involvement of the intervening disk, and moderate epidural extension were features of diffuse brucellar spondylitis. The great majority of joints with scintigraphic evidence of disease demonstrated normal radiographic findings. Evidence of osteomyelitis or destructive arthritis was encountered in only a few cases. Although radiography is sufficient for demonstrating focal brucellosis, MR imaging is better for assessing diffuse disease.

Case report: investigation of chyluria.

We present a case of chyluria in which the demonstration of abnormal lymphaticourinary communication was established by conventional lymphangiography. Radiocolloid lymphoscintigraphy failed to demonstrate the site of leakage, probably due to technical factors which are discussed.

Intracranial xanthogranuloma of the dura in Hand-Schüller-Christian disease. Case report.

The authors describe a 37-year-old man with the classic clinical features of Hand-Schüller-Christian disease. He presented with symptoms of increased intracranial pressure due to obstructive hydrocephalus secondary to a huge xanthogranuloma involving falx cerebri and tentorium cerebelli. Immunohistochemical and ultrastructural studies failed to demonstrate Langerhans histiocytes, however. The implication of this finding is discussed in light of the recent relevant literature.

Premature tracheobronchial, laryngeal and costochondral cartilage calcification in children.

Two children with premature tracheobronchial, laryngeal and costochondral cartilage calcification are described. Both patients had associated congenital cardiovascular anomalies; one of them having features of Keutel syndrome.

Renal colic: diagnosis and outcome.

To assess whether ultrasonography (US) with or without plain abdominal radiography (kidney, ureter, bladder [KUB] radiography) can replace intravenous urography (IVU) in detection of acute urinary tract obstruction, 101 consecutive patients with renal colic were evaluated with US followed immediately by IVU. Receiver operating characteristic (ROC) curves for US diagnosis of acute urinary tract obstruction yielded sensitivities of 91% and 92% for two reviewers at a specificity of 90%. There was no statistically significant difference between US and IVU results. When US was combined with KUB radiography, ROC curves yielded sensitivities of 94% and 97% for two reviewers at a specificity of 90%.KUB radiography alone was of limited diagnostic value. For US alone, no false-positive results occurred, and the false-negative results (n = 9 and n = 6 for two reviewers) were encountered in cases of grade 1 hydronephrosis and nondilated obstructive uropathy. The authors conclude that US combined with KUB radiography can replace IVU in initial evaluation and follow-up of the great majority of patients with renal colic.

Role of MR imaging in the management of spinal infections.

Infection of the spine is a major category of spinal disease that is difficult to differentiate clinically from degenerative disease, noninfective inflammatory lesions, and spinal neoplasm. The infection can affect the vertebrae, intervertebral disks, paraspinal soft tissues, the epidural space, the meninges, and/or the spinal cord. Specific causative organisms include bacteria (pyogenic, granulomatous), fungi, parasites (Echinococcus, Schistosoma), and viruses. Early diagnosis and prompt treatment are essential to prevent permanent neurologic deficit and/or spinal deformity. Imaging plays an important role in the overall evaluation of these lesions, and the ideal technique is expected to provide information that will help characterize and delineate the disease process, guide biopsy and/or drainage procedures, suggest method of treatment (medical vs surgical), and assess response to therapy. The aim of this article is to review the advantages and limitations of MR imaging in the management of spinal infections.

Neurotuberculosis: a review.

Tuberculosis is still a major cause of serious illness in many parts of the world. CNS involvement has frequently been found secondary to tuberculosis elsewhere in the body, particularly the lungs. The disease manifests itself as meningitis, tuberculoma and/or spinal tuberculosis. The presence of tuberculosis elsewhere in the body favors the diagnosis although its absence does not exclude it. While tuberculous meningitis is a disease of childhood, tuberculomas and spinal tuberculosis are invariably an adult manifestation. The great majority of patients with neurotuberculosis are diagnosed and treated early because of characteristic clinical, imaging, and CSF findings. Clinical response to antituberculous therapy in all forms of neurotuberculosis is excellent if the diagnosis is made early before irreversible neurological deficit is established.

MR, CT, and ultrasonography of splanchnic venous thrombosis.

Nine patients with splanchnic venous thrombosis are presented and the value of noninvasive imaging in their initial diagnosis and subsequent follow-up is emphasized. Angiography, traditionally the definitive investigation in such cases, can be reserved for preoperative assessment in those patients considered candidates for surgery. The age of venous thrombi can be estimated by computed tomography (CT) and magnetic resonance imaging (MRI) which aids selection of therapy, and in those anticoagulated, prediction of prognosis.

Mycetoma: comparison of MR imaging with CT.

Magnetic resonance (MR) images obtained in 18 patients with pathologically confirmed mycetoma in the body (n = 4) or lower extremity (n = 14) were retrospectively reviewed and compared with computed tomographic (CT) scans in 15 patients and surgical findings in 10. T1-weighted images showed an infiltrating mass (same signal intensity as muscle) involving skin, subcutaneous fat, muscles, tendons, and other tissues. On T2-weighted images, the mass and affected structures showed moderately increased signal intensity. Bone marrow involvement was detected in seven patients and was best visualized on T1-weighted images. CT showed moderate enhancement of the infiltrative process in all patients. Bone changes, seen in nine, included coarse trabeculation, periosteal reaction, endosteal proliferation, and patchy destruction. MR imaging and CT were comparable and correlated well with surgery in showing the extent of soft-tissue involvement. Early bone changes (important for therapy planning for pedal mycetoma) were seen only at CT. The study showed that MR imaging is sensitive for assessing the extent of mycetoma in the soft tissues. CT should be the method of choice for staging pedal lesions because it can be used to detect early bone involvement.

Granulomatous spinal infections: MR imaging.

The value of magnetic resonance (MR) imaging in evaluating granulomatous spinal infection was retrospectively assessed in 81 patients with proved disease; 27 were reexamined after administration of gadolinium diethylenetriaminepentaacetic acid, and 25 underwent follow-up studies. Blinded interpretations were correlated with clinical, microbiologic, and surgical findings. MR imaging enabled prediction of the presence of neurologic complications in 93% of patients and diagnosis of the type of infection in 94%, and correlated well with surgical findings in 24 of 27 patients. Vertebral intraosseous abscesses, meningeal involvement, subligamentous spread, and paraspinal abscess location were best identified on contrast-enhanced studies and were seen most frequently in tuberculous spondylitis. High signal intensity on T1-weighted images of previously affected vertebrae suggested healing and correlated well with symptoms. The authors conclude that MR imaging may be useful as the method of first choice for the initial assessment and posttherapy follow-up of patients with granulomatous spinal infection.

MR imaging of thoracic and abdominal wall infections: comparison with other imaging procedures.

Infections of the chest and abdominal wall are rare but potentially fatal disorders that can occur spontaneously or in association with diabetes mellitus, immunosuppression, or trauma. The condition (either in the form of necrotizing fasciitis and/or pyomyositis) is difficult to diagnose clinically because of poor localizing signs. Prognosis depends on early recognition, extent of disease, and type of causative organism. Pathologically, the infections can manifest as cellulitis, abscess, and/or granulation tissue formation. To determine the value of MR imaging in the assessment of these infections, we compared the findings of MR with those of CT, sonography, scintigraphy, and plain radiography in 13 patients with proved thoracic and/or abdominal wall infection. The imaging findings were correlated with microbiological, pathologic, and/or surgical data. The isolated pathogens were Staphylococcus aureus (n = 6), Klebsiella pneumoniae (n = 1), Mycobacterium tuberculosis (n = 4), and Streptomyces somaliensis (n = 2). In 10 of 13 patients, MR imaging and CT were comparable and proved accurate in detecting the nature and extent of the inflammatory process. In seven of the patients, CT also was useful in guiding percutaneous biopsy and/or partial drainage procedures. Coronal and sagittal MR images were helpful for planning surgery. Rib osteomyelitis was missed with both techniques in one patient; in two other patients who did not have CT, MR imaging missed osteomyelitis of the ribs, the spinous process of a vertebral body, and the iliac bone. Sonography underestimated the extent of the disease in all 13 patients, but detected fluid collections in six. Findings on scintigraphy and plain radiography were the least contributory to the diagnosis and treatment of these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Bickerstaff brainstem encephalitis. A grave non-demyelinating disease with benign prognosis.

We describe 6 patients with ophthalmoplegia, ataxia and normal or exaggerated deep tendon reflexes. All had been preceded by a febrile illness and had a full recovery without sequelae. The brainstem auditory evoked potentials showed a localised lesion in the upper brainstem while the pattern shift visual evoked potentials were normal and did not show any additional silent lesions. CSF IgG oligoclonal bands were not detected in any of the patients. MRI in 2 patients showed a confluent high intensity lesion in the upper mesencephalon and thalamus involving white and gray matter. Follow-up ranged from 6 to 24 months and showed no relapse.

Brucellar and tuberculous spondylitis: comparative imaging features.

Radiographs, scintigrams, computed tomographic scans, and magnetic resonance (MR) images of 17 patients with brucellar spondylitis and 15 with tuberculous spondylitis were analyzed to identify distinguishing features. Characteristic findings of brucellar spondylitis included predilection for the lower lumbar spine (68% of lesions), bone destruction limited to the end plates, disk collapse (16 of 19 disks), and granulation tissue or localized soft-tissue edema (17 of 19 sites). MR imaging showed diffuse increased signal in vertebrae and disks on long repetition time (TR)/echo time (TE) images in four patients and focal increased signal with normal disks in one. Epidural extension was best seen on short TR/TE images in four. Tuberculous spondylitis was characterized by predilection for the midthoracic spine (73%), vertebral destruction with gibbus deformity (60%), disk collapse, and paraspinal abscesses (14 of 15). On MR images signal intensity of affected vertebrae was similar to but more severe than findings in patients with brucellar spondylitis. Scintigraphy was the least helpful in differentiating the two infections. Lesions of tuberculous spondylitis affecting the lower lumbar spine were difficult to differentiate from those of brucellar spondylitis.

Neurobrucellosis: clinical characteristics, diagnosis, and outcome.

We report 13 patients with neurobrucellosis categorized into five groups: acute meningoencephalitis; papilledema and increased intracranial pressure, meningovascular, CNS demyelinization, and peripheral neuropathy. We treated the patients successfully, without relapse, with two or more antimicrobials: rifampicin, co-trimoxazole, and doxycycline.

Osteoarticular brucellosis: results of bone scintigraphy in 140 patients.

One hundred forty patients with proved brucellosis and clinical evidence of bone and joint involvement were evaluated prospectively by 99mTc-methylene diphosphonate scintigraphy to assess the frequency of positive findings. To evaluate the radiographic abnormalities associated with positive scintigraphy, all areas of the skeleton that showed abnormal uptake were studied further by plain radiography. High-resolution CT was performed in all patients who had spinal lesions. Ninety-six patients (69%) had abnormal radionuclide uptake in 57 extraspinal and 101 spinal sites. Uptake was increased in 53 joints and three long bones and decreased in one joint. The knee was the most frequently involved site; the second was the sacroiliac joint. Radiographic and high-resolution CT changes were seen in only 12 (21%) of 57 extraspinal sites. In the spine, the abnormal scintigrams showed either focal increased uptake in affected vertebral bodies (detected mostly on the anterior view and seen in 51 lower thoracic and lumbar vertebrae in 24 patients) or diffuse increased uptake in adjacent vertebrae (detected in anterior and posterior views and seen in 50 different disk levels in 38 patients). Radiographic and high-resolution CT changes were seen at all scintigraphically positive sites. We conclude that bone scintigraphy is a useful method for screening patients with osteoarticular brucellosis. It is more sensitive than radiography in assessing involvement of the extraspinal skeleton and in the spine, it allows accurate localization of affected areas.