Doppler sonographic enhancement of hepatic hemangiomas and hepatocellular carcinomas after perflenapent emulsion: preliminary study.
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Ultrasonographic microbubble contrast agents improve Doppler signals by increasing blood backscatter. We retrospectively reviewed our experience with perflenapent (EchoGen), an emulsion of liquid dodecafluoropentane, in the evaluation of 13 patients with focal hepatic lesions (10 hemangiomas and six hepatocellular carcinomas). Perflenapent improved the detection of color Doppler flow signals within the lesions. The hemangiomas showed peripheral nonpulsatile signals and the hepatocellular carcinomas showed more diffuse enhancement with both arterial and venous type signals. This preliminary study suggests that perflenapent administration may aid in the sonographic differentiation of these focal lesions. (+info)
Fungal spinal osteomyelitis in the immunocompromised patient: MR findings in three cases.
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The MR imaging findings of fungal spinal osteomyelitis in three recipients of organ transplants showed hypointensity of the vertebral bodies on T1-weighted sequences in all cases. Signal changes and enhancement extended into the posterior elements in two cases. Multiple-level disease was present in two cases (with a total of five intervertebral disks involved in three cases). All cases lacked hyperintensity within the disks on T2-weighted images. In addition, the intranuclear cleft was preserved in four of five affected disks at initial MR imaging. MR features in Candida and Aspergillus spondylitis that are distinct from pyogenic osteomyelitis include absence of disk hyperintensity and preservation of the intranuclear cleft on T2-weighted images. Prompt recognition of these findings may avoid delay in establishing a diagnosis and instituting treatment of opportunistic osteomyelitis in the immunocompromised patient. (+info)
Neurocutaneous melanosis presenting with intracranial amelanotic melanoma.
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We describe imaging findings in a 2-year-old girl with neurocutaneous melanosis and malignant cerebral melanoma. Because the cerebral melanoma in this child was of the amelanotic type, high-signal intensity on unenhanced T1-weighted images was not present. The cutaneous lesions played a crucial role in establishing a correct (presumed) histopathologic diagnosis on the basis of the imaging findings. To our knowledge this is the first report describing an intracranial amelanotic malignant melanoma in association with neurocutaneous melanosis. (+info)
MR imaging of acute coccidioidal meningitis.
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BACKGROUND AND PURPOSE: Our purpose was to describe the MR imaging findings in patients with acute coccidioidal meningitis. METHODS: Fourteen patients (11 men, three women; 22-78 years old; mean age, 47 years) with coccidioidal meningitis underwent neuroimaging within 2 months of diagnosis. Thirteen patients had MR imaging and one had an initial CT study with a follow-up MR examination 5 months later. Initial and follow-up MR images were evaluated for the presence of ventricular dilatation, signal abnormalities, enhancement characteristics, sites of involvement, and evidence of white matter or cortical infarction. The patterns of enhancement were characterized as focal or diffuse. Pathologic specimens were reviewed in two patients. RESULTS: Ten of the 14 images obtained at the time of initial diagnosis showed evidence of meningitis. All of the initially abnormal studies showed enhancement in the basal cisterns, sylvian fissures, or pericallosal region. Subsequent studies, which were available for three of the four patients with normal findings initially, all eventually became abnormal, with focal enhancement seen on the initial abnormal examination. Other abnormalities seen at presentation included ventricular dilatation (six patients) and deep infarcts (four patients). Pathologic specimens in two patients showed focal collections of the organism corresponding to the areas of intense enhancement on MR images. CONCLUSION: Early in its disease course, coccidioidal meningitis may show areas of focal enhancement in the basal cisterns, which may progress to diffuse disease. Pathologically, the areas of enhancement represent focal collections of the organism. Deep infarcts and communicating hydrocephalus are associated findings. (+info)
A new technique of surface anatomy MR scanning of the brain: its application to scalp incision planning.
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BACKGROUND AND PURPOSE: Surface anatomy scanning (SAS) is an established technique for demonstrating the brain's surface. We describe our experience in applying SAS with superposition of MR venograms to preoperative scalp incision planning. METHODS: In 16 patients, scalp incision planning was done by placing a water-filled plastic tube at the intended incision site when we performed SAS using half-Fourier single-shot fast spin-echo sequences. Two-dimensional phase-contrast MR angiograms were obtained to demonstrate the cortical veins and then superimposed upon the SAS images. The added images were compared with surgical findings using a four-point grading scale (0 to 3, poor to excellent). RESULTS: In each case, neurosurgeons could easily reach the lesion. Surgical findings correlated well with MR angiogram-added SAS images, with an average score of 2.56. CONCLUSION: Our simple technique is a useful means of preoperatively determining brain surface anatomy and can be used to plan a scalp incision site. (+info)
High-field, high-resolution MR imaging of the human indusium griseum.
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The human indusium griseum (IG), the paired dorsal continuation of the hippocampus, was investigated with high-field (3.0T) MR imaging. The IG was clearly visible in 16 out of 20 healthy volunteers. The most common pattern was a single lateralized strip. The classical neuroanatomic pattern of paired symmetric strips along the midline was found in one case. The study clearly demonstrates that diminutive, hitherto overlooked structures such as the IG now can be readily investigated in vivo by non-invasive high-field MR imaging. (+info)
Respiratory function in patients with thalassaemia and iron overload.
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Iron deposition in the respiratory system has been proposed as a potential cause of the ventilatory restrictive impairment seen in patients with thalassaemia major (TM) and iron overload. In this study, magnetic resonance imaging (MRI) measurements of the liver (T2 relaxation time) were used as a surrogate index of total body iron burden and the extent to which these measurements correlated with total lung capacity (TLC) in patients with TM was examined. Twenty-one patients (aged 25+/-5 yrs) with TM participated in the study. Standard pulmonary function tests were undertaken and the T2 relaxation time of the liver was measured in all patients. Ventilatory restrictive impairment (mean TLC 74+/-11 (SD)% predicted) was the most common abnormality found in 71% of TM patients. There was no correlation between TLC (% pred) and T2 relaxation time (r=0.06, p=0.78). T2 relaxation time correlated weakly with average serum ferritin levels (r=-0.56, p=0.008). In conclusion, the data do not support the notion that the restrictive impairment in patients with thalassaemia major and iron overload is related to iron deposition in the respiratory system. (+info)
Thyroglossal duct cysts: sonographic appearances in adults.
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BACKGROUND AND PURPOSE: Previous reports have suggested that thyroglossal duct cysts (TDCs) appear on sonograms as well-defined cystic masses with thin walls and posterior enhancement. In our experience, however, TDCs have a variable sonographic appearance. We report our findings in 40 patients with TDCs and document the variability of sonographic patterns. METHODS: All patients in whom the diagnosis of TDC was made clinically (by at least two head and neck surgeons) and sonography detected a cystic mass related to the hyoid bone were included in this study. Sonograms of 40 patients with TDCs were reviewed. The features evaluated were the location, internal echogenicity, posterior enhancement, presence of septa, solid component, and fistulous tract. The echo pattern was not compared with the biopsy results. RESULTS: Four patterns of TDCs were identified: anechoic (28%), homogeneously hypoechoic with internal debris (18%), pseudosolid (28%), and heterogeneous (28%). The majority showed posterior enhancement (88%), were midline (63%), and infrahyoid in location (83%). Only half of all TDCs showed a typical thin wall. CONCLUSION: On sonograms, TDCs in adults are not simple cysts, as previously suggested, but have a complex pattern ranging from a typical anechoic to a pseudosolid appearance. (+info)