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Biomedical subjects

V Dunn

Publications and source records attributed to V Dunn.

18 recordsLinked to original sources

Magnetic resonance imaging of children with Duchenne muscular dystrophy.

Eight children representing a spectrum of clinical states of biopsy-proven Duchenne muscular dystrophy (DMD) underwent magnetic resonance (MR) scans to assess the degree of muscular involvement and disease progression. Five muscle groups (neck, shoulder girdle, pelvic girdle, thigh and calf) were evaluated. In each case, involved muscles were clearly demarcated. Image estimates of disease severity by degree of muscle involvement correlated well with clinical staging. In our experience MR is useful for assessment of disease stage, selection of appropriate muscles for biopsy and planning for courses of physical and rehabilitation therapy.

Adipose Tissue

Magnetic resonance imaging of the spine in children.

We reviewed the magnetic resonance imaging (MRI) scans of the spine of 42 children who had neurologic signs compatible with lesions of the spinal cord. Twenty-three of the children had abnormalities identified by MRI. The spectrum of abnormalities included posttraumatic lesions, tumor, tethered cord, and syringohydromyelia. Tethered cord with or without lipoma and syringohydromyelia were the most common findings, affecting six and four children, respectively. Thirteen children studied by MRI also underwent conventional metrizamide myelography and/or computed tomography. In 12 cases, the findings of MRI were comparable to those of myelography and computed tomography. These observations indicate that MRI effectively detects lesions of the spinal cord in children. Because MRI can be performed on an outpatient basis and avoids the risks of metrizamide myelography, we conclude that MRI should be considered to be the preferred screening technique for children with suspected spinal cord disorders.

Adolescent

Structural abnormalities in the frontal system in schizophrenia. A magnetic resonance imaging study.

Thirty-eight schizophrenics and 49 normal controls underwent magnetic resonance imaging. Midline sagittal cuts indicated that the schizophrenics had significantly smaller frontal lobes, as well as smaller cerebrums and craniums. The findings are consistent with some type of early developmental abnormality that might retard brain growth and therefore skull growth. These findings are confirmed on a smaller sample of patients on whom we have coronal cuts. Decreased cerebral and cranial size are associated with prominent negative symptoms, although decreased frontal size is not. Decreased cranial and cerebral size was also associated with impairment on some cognitive tests. These findings are consistent with the hypothesis that some schizophrenics may have a type of early developmental abnormality associated with prominent negative symptoms and cognitive impairment. Further, the results suggest that schizophrenics may have a type of structural frontal system impairment. Thus, they provide anatomic evidence for the "hypofrontality hypothesis."

Adult

Cerebellar infarction: comparison of computed tomography and magnetic resonance imaging.

We correlated clinical, computed tomographic (CT), and magnetic resonance imaging (MRI) findings in 14 patients with cerebellar infarctions. Before MRI, the diagnosis of cerebellar infarction was made in only 7 patients on the basis of clinical and CT evidence. Cerebellar infarction was bilateral in 3 patients and was associated with brainstem infarction in 6. Infarction occurred in the territory of the posterior inferior cerebellar artery (PICA) in 12 patients. The territory of the superior cerebellar artery (SCA) was involved in 1 patient, and 1 infarction encompassed the watershed between the PICA and the SCA. In patients with infarction of the PICA territory, the medial and intermediate hemispheric segments were most frequently involved. Involvement of the lateral hemispheric segment was infrequent and was independent of brainstem involvement. Because of its fine demonstration of anatomical detail, its lack of bony artifact, and its ability to visualize infarctions readily within the first 24 hours, MRI is an excellent method for demonstrating cerebellar infarction.

Adult

Detection of heterotopic gray matter in children by magnetic resonance imaging.

Heterotopic gray matter results from abnormal brain development and is a recognized focus of seizures. It may be associated with mental retardation and/or severe malformations of the brain. Three patients with heterotopia of gray matter were identified by magnetic resonance imaging (MRI). CT failed to detect the heterotopic gray matter in each case. One child was referred for removal of a neoplasm based on CT studies until MRI demonstrated the developmental nature of his condition. One infant had severely dysplastic left cerebral hemisphere associated with heterotopic gray matter and the syndrome of Hypomelanosis of Ito. All three children suffered from seizures and/or mental retardation. MRI provided important information in the management of each case and appears to be the imaging method of choice in evaluating children with seizures or retardation for heterotopic gray matter in the brain.

Brain Neoplasms

Impact of MR imaging on clinical diagnosis and management: a prospective study.

The clinical value of magnetic resonance (MR) imaging was prospectively evaluated in 189 patients referred for examination of the brain or spine. Comparison of the attending physician's diagnosis, proposed treatment, and estimated prognosis before and after MR imaging indicated a substantial effect of the additional information provided by this study. A suspected diagnosis was refined or changed in 16% of all patients, and the physician's level of confidence in the diagnosis changed in over half of the cases in which the diagnosis was unchanged. In two-thirds of all cases the physician indicated that the treatment or estimated prognosis was altered.

Brain Diseases

Partial dorsal mesencephalic hemorrhages: report of three cases.

We studied three patients with spontaneous dorsal mesencephalic hemorrhages. One patient had Parinaud's syndrome with a unilateral hemorrhage confined to the rostral tectal plate. The second patient had vertical gaze palsy, skew deviation, and bilateral Horner's syndrome due to a unilateral hemorrhage that involved the superior colliculus and extended anteriorly into the midbrain tegmentum and inferiorly to the rostral dorsal pons. The third patient had a hemorrhage in the caudal tectal plate, with bilateral fourth cranial nerve palsies, unilateral Horner's syndrome, and ataxia. There was hydrocephalus due to obstruction of the aqueduct in two patients. The patients recovered, but with some degree of disability.

Adult

Syndrome of the paramedian thalamic arteries: clinical and neuroimaging correlation.

Two patients had sudden alteration of consciousness followed by fluctuating hypersomnia and bilateral ophthalmoplegia. Magnetic resonance imaging showed asymmetric, paramedian thalamic and midbrain lesions. The clinical and neuroimaging features are consistent with the syndrome of the paramedian thalamic arteries of the basilar communicating artery. These strokes were caused by an embolus to the rostral basilar artery originating from a fibrillating heart. Magnetic resonance imaging clearly delineates the delicate pattern of arterial involvement in mesodiencephalic junction infarctions.

Aged

Jejunal diverticulosis and chronic pneumoperitoneum.

A unique case of pneumoperitoneum, without peritonitis or perforation, associated with jejunal diverticulosis is presented. Pneumoperitoneum is documented over the course of many years, with recurrence after partial small bowel resection. Jejunal diverticulosis is one of the leading gastrointestinal causes of pneumoperitoneum without peritonitis or surgery. The distended diverticular mucosa may function as a semipermeable membrane allowing transmural gas equilibration.

Aged

Hemodynamic studies using a CT scanner.

New CT software programs allow rapid-sequence images to be obtained. During a period of 12 sec, multiple CT images can be produced, so that the progression of contrast flow at intervals of 1 sec or less can be followed. In addition, as many as 16 consecutive 3-sec scans can be performed, or arbitrary time intervals inserted between scans. The rapidity with which the contrast medium enters and leaves a specific tissue may be a valuable, non-invasive diagnostic tool in differentiating enhancing lesions. Other potential applications are mentioned.

Hemodynamics

Familial hyperphosphatasemia: diagnosis in early infancy and response to human thyrocalcitonin therapy.

Familial hyperphosphatasemia is an uncommon hereditary disorder of membranous bone with concurrent overproduction and overdestruction of bone and bone collagen by osteocytes. This process does not allow normal maturation into compact lamellar bone. Two cases of severely affected children are presented which demonstrate that the condition can be diagnosed in early infancy by abnormalities in the long bones. At this stage the skull may appear normal and the characteristic thickening of the calvarium appears later. The disease is treatable with human thyrocalcitonin; these and previously reported cases have responded favorably.

Age Factors

Ferritin and intestinal iron absorption: pancreatic enzymes and free iron.

Rat intestinal mucosa gave low yields of ferritin purified by standard procedures. The resulting ferritin had less protein relative to iron and migrated faster electrophoretically than ferritin from other rat tissues. Pancreatic duct ligation reduced these differences, suggesting digestive enzyme attack during ferritin isolation. Even in ligated rats, ferritin accounted for only 5-10% of mucosal iron. However, shortly after giving 59FeCl3 orally, 50% of mucosal radioactivity occurred in cell sap, about equally distributed between ferritin and low-molecular-weight (chelated?) iron. No other cell sap components were 59Fe labeled. Iron may thus be transported as a chelate with which ferritin is in rapid equilibrium. Mucosal ferritin content increased with age and iron treatment and decreased with iron deficiency. The iron-deficient rats showed accelerated 59Fe uptake into blood with little mucosal retention. One day after administering parenteral iron to deficient rats, 59Fe transfer to blood became retarded but 59Fe now accumulated excessively in the mucosa, suggesting that iron status affects transport more rapidly at the serosal than at the mucosal cell surface. A scheme for control of iron absorption is presented.

Age Factors

Magnetic resonance imaging in Wallenberg's lateral medullary syndrome.

Four patients with a clinical diagnosis of Wallenberg's lateral medullary syndrome were studied with both Magnetic Resonance Imaging (MRI) and cranial Computed Tomography (CT). Using transverse images and both T1 and T2--weighted sequences, MRI demonstrated a medullary infarction not seen on CT in all four cases. MRI also demonstrated a coexisting cerebellar infarction in three cases which was unsuspected clinically and undetected by CT.

Adult

Dichotomy between clinical findings and MR abnormalities in pontine infarction.

Comparison between cranial CT and magnetic resonance (MR) imaging in 10 patients with recent pontine infarction indicates a distinct superiority for MR. However, MR changes often failed to correlate with the degree of neurological dysfunction. Regions of abnormal signal intensity appeared to involve areas with normal neurologic function.

Adult