MRI of angiosarcoma of the calvaria.
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Aged↗
Biomedical subjects
Mauricio Castillo
Publications and source records attributed to Mauricio Castillo.
Hyperacute subarachnoid hemorrhage on T2-weighted MR images.
We describe a case of hyperacute subarachnoid and intraventricular hemorrhage from a ruptured aneurysm, which occurred while the patient was undergoing MR imaging. Compared with CSF, the blood in the subarachnoid space had slightly lower signal intensity on T2*-weighted gradient-echo images and increased signal intensity on T2-weighted spin-echo images. This finding differs from the generally accepted MR appearance of intracranial hemorrhage and should be recognized to ensure proper patient care.
Acute Disease↗
Differentiation of toxoplasmosis and lymphoma in AIDS patients by using apparent diffusion coefficients.
BACKGROUND AND PURPOSE: Distinguishing between toxoplasmosis and lymphoma brain lesions in AIDS patients is difficult but clinically relevant. This study was performed to test the hypothesis that diffusion-weighted (DW) imaging with apparent diffusion coefficient (ADC) maps can be used to distinguish these two lesions. METHODS: The ADC values were calculated in regions of interest placed in 13 brain toxoplasmosis lesions and eight brain lymphoma lesions in patients with AIDS. These values were compared with those of normal white matter. ADC ratios in lymphoma lesions then were compared with those in toxoplasmosis lesions by using a two-sample two-tailed t test. RESULTS: Toxoplasmosis lesions demonstrated significantly greater diffusion than that of lymphoma lesions (P =.004). ADC ratios were 1.63 +/- 0.41 (mean +/- standard deviation) in the 13 toxoplasmosis lesions and 1.14 +/- 0.25 in the eight lymphoma lesions. While considerable overlap was present for ADC ratios between 1.0 and 1.6, ADC ratios greater than 1.6 were associated solely with toxoplasmosis, accounting for seven of 13 toxoplasmosis lesions. CONCLUSION: ADC values are helpful in differentiating toxoplasmosis from lymphoma in patients with AIDS.
AIDS-Related Opportunistic Infections↗
Development of de novo intracranial aneurysm in three months: case report and literature review.
SUMMARY: Formation of de novo intracranial aneurysms is rare. Their etiology is not known, but they are seen in patients with inherited collagen disorders, polycystic kidney disease, and familial history of aneurysms. Most de novo intracranial aneurysms are found 3-20 years after diagnosis of the initial aneurysm. We report the imaging findings in a 46-year-old man who developed a de novo intracranial aneurysm only 3 months after surgical clipping of another aneurysm.
Aneurysm↗
Unusual MR spectroscopic imaging pattern of an astrocytoma: lack of elevated choline and high myo-inositol and glycine levels.
We present the case of a patient with an MR imaging study showing an ill-defined intra-axial mass in the right insula and frontal lobe. The mass showed high signal intensity on T2-weighted and fluid-attenuated inversion recovery images and an unusual proton MR spectroscopic imaging pattern characterized by the presence of high levels of myo-inositol/glycine, no significant elevation of choline, and mildly reduced N-acetylaspartate. The histopathologic diagnosis was of diffuse astrocytoma with oligodendroglial components (World Health Organization grade II).
Adult↗
Cranial fasciitis of childhood.
Cranial fasciitis is a benign fibroblastic tumor of the skull found almost exclusively in young children. It is histologically identical to nodular fasciitis. We present the clinical, radiologic, and pathologic findings of a 7-month-old male infant with cranial fasciitis of the skull. Herein, we include the first description of this entity's diffusion-weighted imaging appearance. Although rare, cranial fasciitis can mimic more aggressive processes both clinically and radiographically.
Diagnosis, Differential↗
Apparent diffusion coefficient measurements in the hippocampi in patients with temporal lobe seizures.
BACKGROUND AND PURPOSE: Loss of neurons results in a relative increase in extracellular space that may lead to altered apparent diffusion coefficient (ADC) values in the hippocampi of patients with seizures. Our purpose was to determine if ADC values along the long axis of hippocampi are useful in evaluating patients with partial complex seizures. METHODS: Hippocampi of 23 patients with partial complex seizures and 25 healthy volunteers were evaluated with MR imaging and ADC maps. MR images were evaluated for loss of volume and/or high signal intensity on T2-weighted images and compared with ADC maps. ADCs were compared between patients and controls, as were ADCs along the length of each hippocampus. Mean and SDs were obtained for each measurement, and level of significance was determined (P <.05). The relationship between clinical lateralization and MR imaging and ADCs was studied. RESULTS: No significant variations were found in the ADCs in controls (side to side and along hippocampi). In patients, abnormalities were seen with MR imaging alone in 16, with ADC in 14, and with both in 21. Of 23 hippocampi with an abnormal MR appearance, 14 had abnormal ADCs. Nine hippocampi with a normal MR appearance had abnormal ADCs. Normal MR appearance and ADCs were seen in 13 hippocampi. Most abnormal ADCs were seen in the anterior aspect of the hippocampi. All differences were statistically significant. Of 19 patients who underwent clinical testing, unequivocal lateralization was established in 10. Concordance between clinical tests and MR imaging, ADC, and MR imaging plus ADC was found in five, five, and seven patients, respectively. CONCLUSION: Visual assessment was better than ADCs alone for detection of abnormal hippocampi. MR imaging plus ADCs was better than either technique alone. ADCs may be abnormal when MR images are unremarkable. Concordance with clinical lateralization was better when MR imaging and ADC were jointly evaluated than when either technique was evaluated separately.
Adolescent↗
Bilateral congenital absence of the internal carotid artery.
Bilateral congenital absence of the internal carotid artery was incidentally found in an 11-year-old boy. Magnetic resonance imaging showed a normal-appearing brain that was entirely supplied by the vertebrobasilar system, and CT confirmed the absence of the bony carotid canals. Although most reported patients with agenesis of both internal carotid arteries presented with cerebrovascular lesions, this case demonstrates that this rare malformation may be asymptomatic.
Abnormalities, Multiple↗
Bilateral congenital absence of the internal carotid artery.
Bilateral congenital absence of the internal carotid artery was incidentally found in an 11-year-old boy. Magnetic resonance imaging showed a normal-appearing brain that was entirely supplied by the vertebrobasilar system, and CT confirmed the absence of the bony carotid canals. Although most reported patients with agenesis of both internal carotid arteries presented with cerebrovascular lesions, this case demonstrates that this rare malformation may be asymptomatic.
Basilar Artery↗
False-negative contrast MRA in the setting of carotid artery dissection.
A case of false-negative contrast magnetic resonance angiography (MRA) in the setting of significant carotid stenosis caused by a carotid arterial intimal dissection is described. If arterial dissection is suspected but contrast MRA is normal, additional evaluation may be warranted. In this case the abnormality was detectable on 2D time-of-flight MRA and contrast digital subtraction arteriography. Since MRA has become a commonly used initial screening test for carotid stenosis, it is important to understand the possibility of false-negative results.
Journal Article↗
Isolated tuberculosis of posterior elements of spine: magnetic resonance imaging findings in 33 patients.
STUDY DESIGN: Study of magnetic resonance imaging (MRI) of tuberculosis of spine to determine the incidence and features of isolated tuberculous involvement of the posterior spinal elements. OBJECTIVE: To describe the MRI findings in patients with isolated tuberculous involvement of the posterior spinal elements. SUMMARY OF BACKGROUND DATA: Spinal tuberculosis is more common in the eastern countries than in the western world. Recently, there has been a renewed interest in tuberculosis in the west because of its re-emergence, especially in immunocompromised patients (e.g., HIV). The classic radiologic picture of "two vertebral disease with the destruction of the intervertebral disc" is easily recognized and readily treated, but its atypical forms are often misdiagnosed and mistreated. METHOD: A total of 33 patients 13-53 years of age (16 men, 17 women; mean age 28.30 years) with proven tuberculosis of posterior element of the spine were retrospectively evaluated. The clinical and imaging data were studied in all 33 patients. RESULTS: Involvement occurred from C2 to L5 vertebral levels. Most commonly, involvement was seen in the thoracic vertebrae (16 patients, 48.5%) followed by lumbar vertebrae (13 cases, 39.4%) and cervical vertebrae (4 patients, 12.1%). The laminae were most commonly involved (24 patients, 72.7%; 8 bilateral, 16 unilateral) followed by pedicles (20 patients, 60.6%; 6 bilateral, 14 unilateral), articular processes (19 patients, 57.5%; 5 bilateral, 14 unilateral), spinous processes (19 patients, 57.5%), and transverse processes (12 cases, 36.4%; 5 bilateral, 7 unilateral). Bone destruction and marrow changes were seen in all patients. Involvement of the entire posterior arch was seen in eight patients. A total of 23 patients revealed extraspinal soft tissue collections. Intraspinal extradural granulation tissue/abscess was seen in 11 patients. Spinal cord was either displaced or compressed in 15 patients, and abnormal high signal intensity intrinsic cord changes were seen in eight patients. CONCLUSION: In tuberculosis of the posterior element of the spine, MRI is extremely useful in evaluating the extent of involvement and response to therapy of isolated tuberculosis of posterior elements. Involvement of posterior elements due to tuberculosis is not so uncommon.
Adolescent↗
Imaging of the upper cranial nerves I, III-VIII, and the cavernous sinuses.
This article discusses the upper cranial nerves (I, III-VIII) and their anatomy as it pertains to intra-axial nuclei and tracts, cisternal portions, and extracranial portions. In addition, the most common pathologic processes affecting the upper cranial nerves are discussed and illustrated. Because the evaluation of small structures requires imaging techniques that provide high resolution and contrast, MR imaging is the examination of choice. CT still plays a limited but important role in the evaluation of intraosseous portions of some cranial nerves.
Abducens Nerve↗
Acute tuberculous abscess of the thyroid gland.
Isolated tuberculous thyroid abscess is an extremely rare form of infection of the thyroid gland. We present a case of a female patient who presented with an acute abscess of thyroid gland associated with pain and fever and without cervical lymphadenopathy. We describe the pathology of the disease and the imaging findings with their differential diagnosis.
Abscess↗
Diffusion-weighted magnetic resonance imaging.
Diffusion-weighted magnetic resonance imaging is a specialized technique that measures the degree of diffusion of water molecules within extracellular space and between intracellular and extracellular space. Diffusion-weighted imaging signal is high (bright) when diffusion is restricted, as occurs in cytotoxic damage from ischemia, inflammation, trauma, or tumor. This technique, now available on most magnetic resonance imaging units, is especially helpful in detecting early ischemic stroke and multiple sclerosis and in differentiating arachnoid cyst from epidermoid tumor and brain abscess from neoplasm.
Brain↗
Clinical applications of proton MR spectroscopy in oncology.
Proton magnetic resonance spectroscopy (H1-MRS) has been increasingly receiving more attention from radiologists, neurosurgeons, radiation and medical oncologists in the "in situ" clinical evaluation of human tumors. The utilization of H1-MRS, especially in human brain tumors, coupled to both routine magnetic resonance imaging (MRI) and functional MRI techniques provides greater information concerning tumor grading and extension and characterization of the normal surrounding tissue than what is possible with any other imaging technique alone. In this paper, we will review the current status of proton MR spectroscopy with emphasis on its clinical utility to diagnose tumors, its utility in planning surgical and radiation therapy interventions, and in its use in monitoring tumor treatment.
Brain Neoplasms↗
Atypical meningioma spreading via the perivascular spaces.
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Brain↗
Lumbosacral epidural abscess due to hidradenitis suppurativa.
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Diabetes Complications↗
The palatovaginal canal: can it be identified on routine CT and MR imaging?
OBJECTIVE: The palatovaginal canal is a short bone tunnel that extends from the pterygopalatine fossa to the roof of the pharynx. The primary purpose of our work was to establish whether the palatovaginal canal can be identified on CT and MR imaging. The secondary goal was to establish the frequency of visualization and the appearance of this canal. MATERIALS AND METHODS: We retrospectively analyzed 150 consecutive direct coronal CT studies obtained for evaluation of the sinonasal cavities. Frequency, bilaterality, and appearance of the palatovaginal canals were recorded. The frequency of the vidian canals was recorded for comparison. We also analyzed 20 MR imaging studies of that area to assess visualization of the palatovaginal canals and their contents. A dry skull specimen was examined using CT, and the images were correlated with those obtained in vivo. RESULTS: The palatovaginal canal could be identified on CT on at least one side in 88 (58.7%) of 150 patients. Unilateral complete canals were found in 14 patients (9.3%), and unilateral semicanals were evident in 17 (11.3%). Bilateral complete canals were seen in 24 patients (16%), and bilateral semicanals were found in 11 (7.3%). In 22 patients (14.7%), one complete canal and one semicanal were detected. Fifty-five percent of the visualized canals were completely formed. The palatovaginal canal and its internal tubular structure, presumably corresponding to the pterygovaginal artery, were depicted on 40% of the MR imaging studies. The position and configuration of this canal as seen on CT of the dry skull specimen correlated well with the imaging findings. CONCLUSION: The palatovaginal canals are commonly depicted on CT and MR imaging.
Adolescent↗