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D Schellinger

Publications and source records attributed to D Schellinger.

87 records · Page 5Linked to original sources
PubMedDate not supplied

Functional MRI of human olfaction.

PURPOSE: Our goal was to use functional MRI (fMRI) to measure brain activation in response to olfactory stimuli. METHOD: fMRI brain scans were obtained in 17 normal subjects (9 men, 8 women) using-multislice FLASH MRI in response to three olfactory stimuli (pyridine, menthone, amyl acetate) in three coronal brain sections selected from anterior to posterior temporal brain regions. Activation images were derived using correlation analysis, and ratios of areas of brain activated to total brain areas were calculated. RESULTS: Activation was present in each section in all subjects. Subjective estimation of vapor intensity followed relative vapor pressure of stimuli presented (pyridine > amyl acetate > menthone) and were similar for both men and women. However, brain activation did not follow subjective responsiveness order but rather pyridine > menthone > amyl acetate, a pattern demonstrated by both men and women. Brain activation in women was consistently lower than in men for all vapors in all brain sections, although regions of activation did not differ. Activation occurred in regions previously recognized as associated with olfactory stimulation, including orbitofrontal and entorhinal cortex; however, extensive regions within frontal cortex including cingulate gyrus were also activated. Brain regions activated to odors considered pleasant or unpleasant did not differ. CONCLUSION: The techniques used in this study demonstrated that brain activation to olfactory stimuli could be measured quantitatively such that differences between groups of subjects (in this case men and women) could be compared. Although localization of brain activation was not the major thrust of this study, activation to olfactory stimuli was found not only in brain regions previously associated with processing of olfactory information but also in several other areas of frontal cortex, in cingulate gyrus, and in several components of the limbic system. This is the first study in which activation in human brain parenchyma of normal humans to olfactory stimuli has been quantitated by fMRI.

Adult↗
PubMedDate not supplied

Mapping brain activation to odorants in patients with smell loss by functional MRI.

PURPOSE: Our goal was to use functional MRI (fMRI) to develop an objective, noninvasive technique by which patients with smell loss can be identified, their abnormalities quantitated, their results compared with findings in normal subjects, and visual representation of their CNS pathology obtained. METHOD: Functional MR brain scans were obtained in eight patients with hyposmia in response to three olfactory stimuli (pyridine, menthone, amyl acetate) in three coronal brain sections selected from anterior to posterior temporal brain regions using multislice FLASH MRI. Results were compared with similar studies performed in 17 normal subjects. Activation images were derived using correlation analysis, and ratios of area of brain activated to total brain area were obtained. RESULTS: Brain activation to each stimulus was lower in each section in patients compared with normal subjects and reached statistical significance for mean activation for each odor and in six of the nine individual sections studied. Activation in patients was found in regions previously associated with CNS processing of olfactory stimuli in normal subjects, but activation in patients was much less, particularly in inferior frontal and cingulate gyral regions of frontal cortex and in regions of medial and posterior temporal cortex. CONCLUSION: These results demonstrate quantitative CNS changes in smell function in response to olfactory stimuli in patients with hyposmia, demonstrate a novel, objective method by which these patients can be identified, and provide maps of the CNS changes associated with their smell loss.

Adult↗
PubMedDate not supplied

Increased brain activation in response to odors in patients with hyposmia after theophylline treatment demonstrated by fMRI.

PURPOSE: Our goal was to demonstrate that medical therapy in patients with smell loss (hyposmia) that restored olfactory function toward or to normal could be verified and quantitated by functional MRI (fMRI) of brain and that visual representation of these changes could be used to identify these patients. METHOD: Multislice FLASH MR or echo planar MR brain scans were obtained in four patients with hyposmia in response to three olfactory stimuli both before and after treatment with theophylline. Activation images were derived using correlation analysis, and ratios of brain area activated to total brain area were obtained. RESULTS: Prior to treatment, all patients stated that they could not smell; these losses were confirmed by standard psychophysical tests. At this time, fMRI brain activation in response to odors was significantly less than that measured in normal volunteers and similar to activation measured previously in other patients with a similar type of hyposmia. After treatment, subjective smell function improved in three patients and no improvement occurred in one; results were confirmed by psychophysical tests. In each patient in whom smell acuity improved, brain activation in response to each odor increased in each section and mean activation increased significantly for each odor. Activation increased in all regions previously associated with olfactory stimulation and was particularly apparent in orbitofrontal cortex, frontal lobe component of cingulate gyri, temporal lobe gyri, and hippocampus. There also was consistent activation in superior, middle, and inferior frontal lobe gyri. There were no changes in brain activation after treatment in the patient in whom smell did not improve. CONCLUSION: These results demonstrate that theophylline is an effective therapeutic agent to correct hyposmia in some patients with smell loss. These changes have been documented by fMRI brain scans using olfactory stimuli. This is the first study in which this type of objective improvement following medical treatment has been demonstrated in patients with hyposmia.

Adult↗
PubMedDate not supplied

Odor memory induces brain activation as measured by functional MRI.

PURPOSE: Our goal was to use functional MRI (fMRI) to measure brain activation in response to imagination of odors in humans. METHOD: fMR brain scans were obtained in 21 normal subjects (9 men, 12 women) using multislice FLASH MRI in response to imagination of odors of banana and peppermint and to the actual smells of the corresponding odors of amyl acetate and menthone, respectively, in three coronal sections selected from anterior to posterior temporal brain regions. Similar studies were obtained in two patients with hyposmia using FLASH MRI and in one patient with hyposmia using echo planar imaging, both before and after theophylline treatment, which returned smell function to or toward normal in each patient. Activation images were derived using correlation analysis, and ratios of areas of brain activated to total brain areas were calculated. RESULTS: Activation was present in each section in all normal subjects and in each patient after imagination of each vapor. In normal subjects, brain activation in response to imagination of odors was significantly less than that in response to the actual smell of these odors, and activation following imagination of banana odor was significantly greater in men than in women, as was previously reported for the actual smell of the odor of amyl acetate. However, in relative terms, albeit at an absolute lower brain activation level, the ratio of brain activation by imagination of banana to activation by actual amyl acetate odor was about twice as high in women as in men. Before treatment, in patients with hyposmia, brain activation in response to odor imagination was greater than after presentation of the actual odor itself. After treatment, in patients with hyposmia in whom smell acuity returned to or toward normal, brain activation in response to odor imagination was not significantly different quantitatively from that before treatment; however, brain activation in response to the actual odor was significantly greater than that in response to imagination of the corresponding odor. Brain regions activated by both odor imagination and actual corresponding odor were similar and consistent with regions previously described as responding to odors. CONCLUSION: These studies indicate that (a) odors can be imagined and similar brain regions are activated by both imagined and corresponding actual odors; (b) imagination of odors elicits quantitatively less brain activation than do actual smells of corresponding odors in normal subjects; (c) absolute brain activation in men by odor imagination is greater than in women for some odors, but on a relative basis, the ratio for odor imagination to actual smell in women is twice that in men; (d) odor imagination, once the odor has been experienced, is present, recallable, and capable of inducing a relatively constant degree of brain activation even in the absence of the ability to recognize an actual corresponding odor.

Adult↗
PubMedDate not supplied

Taste memory induces brain activation as revealed by functional MRI.

PURPOSE: Our goal was to use functional MRI (fMRI) to measure brain activation in response to imagination of tastes in humans. METHOD: fMR brain scans were obtained in 31 subjects (12 men, 19 women) using multislice FLASH MRI and echo planar imaging (EPI) in response to imagination of tastes of salt and sweet in coronal sections selected from anterior to posterior temporal brain regions. Activation images were derived using correlation analysis, and ratios of areas of brain activated to total brain areas were calculated. Total activated pixel counts were used to quantitate regional brain activation. RESULTS: Activation was present in each section in all subjects after imagination of each tastant. Activation was similar in response to imagination of either salt or sweet and was quantitatively similar to that previously reported in response to imagination of odors of banana and peppermint. Activation was similar in both men and women as opposed to previous results of odor memory in which activation in men was greater than in women. However, subjective responses of intensity of imagined tastes were significantly greater than those previously obtained for odor memory and were consistently, albeit not significantly, greater in women than in men, similar to results previously reported for odor memory. Brain regions activated in response to taste imagination were consistent with regions previously described as involved with actual taste perception in both humans and animals. Regional brain localization for salt and sweet memories could not be differentiated. CONCLUSION: These studies indicate that (a) tastes can be imagined, (b) brain regions activated for taste imagination are consistent with regions previously described for actual taste perception, and (c) similar to odor memory for banana and menthone, regional brain localization for salt or sweet taste memories could not be differentiated.

Adult↗
PubMedDate not supplied

MR of slow CSF flow in the spine.

PURPOSE: To evaluate a slow-flow MR sequence in normal CSF flow and in CSF flow disturbance in cases of spinal stenosis. METHOD: The method was tested for flow sensitivity and applied to 67 sites of spinal canal compromise. RESULTS: Phantom studies show that flow can be depicted at a velocity of 0.5-1 mm/sec. On clinical images, stagnant CSF is black, flowing CSF is bright. Typically, in high-grade (90%-100%) stenosis, CSF above and below the site of spinal canal compromise (SCC) is black. With intermediate stenosis (50%-89%), CSF above the SCC remains white but becomes black distal to the SCC. Low-grade stenosis shows only localized flow disturbances. CONCLUSION: This easy-to-use sequence can solidify the MR diagnosis of high-grade stenosis when a distinct flow pattern is recognized. Flow patterns for intermediate and low-grade stenosis are less reliable.

Cerebrospinal Fluid↗
PubMedDate not supplied

Periventricular leukomalacia in combination with intraventricular hemorrhage: sonographic features and sequelae.

Periventricular leukomalacia (PVL) is well recognized as a relatively uncommon yet particularly serious complication of prematurity. Although the sonographic features of PVL have been described, its association with intraventricular hemorrhage (IVH) has not been emphasized. Reviewing 26 consecutive cases of PVL in neonates of 34 weeks or less gestational age, significant associated hemorrhage was found in six (23%). Small quantities of blood were also noted in most of the other 20 infants. Of the six infants with both significant IVH and PVL, five required ventricular shunt and all had particularly poor clinical outcomes. In the neonates who required surgical intervention, rapid ventricular enlargement was accompanied by extensive periventricular cyst formation. Eventually, the septations within the cysts and frequently even the ependyma of superior/posterior lateral ventricles degenerated. Cysts merged imperceptibly with the ventricles giving an appearance that mimicked severe hydrocephalus. This was termed "pseudoventricle formation," as the large intracerebral cerebrospinal fluid spaces are primarily porencephaly and not enlarged ventricles. Response to shunting was minimal by sonography in all five cases and multiple shunt revisions were required in four. Clinical follow-up in children with significant IVH in combination with PVL has shown severe mental retardation and tetraplegia in all cases.

Cerebral Hemorrhage↗
PubMedDate not supplied

Ventricular septa in the neonatal age group: diagnosis and considerations of etiology.

Twenty-four patients with ventricular septa are discussed. Seventeen patients had septa acquired during the neonatal period and seven exhibited septations at birth (cogenital septa). Among the acquired septa, there were true intraventricular septa and septa that originated outside the ventricles but later became part of the ventricular system (pseudosepta). Pseudosepta originate in necrotic, cavitating periventricular white matter that, in temporal sequence, becomes ventricularized. Serial use of cranial sonography provided important information about the pathologic mechanisms that govern the development of septa. Intraventricular hemorrhage and infection are the major causes of true intraventricular septa, while periventricular leukomalacia serves as primary cause of pseudosepta. Sonography is the diagnostic method of choice. Septa are associated with a high incidence (62%) of shunt failure.

Brain Diseases↗
PubMedDate not supplied

Thin-section CT of midbrain abnormalities in progressive supranuclear palsy.

Thin-section computed tomographic (CT) scans of 3 and 1.5 mm thickness were obtained using the Philips Tomoscan 310 and General Electric 8800 CT/T scanners in the study of 10 consecutive patients with progressive supranuclear palsy (PSP) and 31 patients with other diseases. Marked midbrain and moderate pontine atrophy, a dilated third ventricle, and enlarged quadrigeminal plate cisterns were observed in all PSP cases. The aqueduct was dilated in several. In six of the PSP cases, there was a striking midbrain abnormality in the form of a low-density area extending from the interpeduncular cistern toward the aqueduct. Thin-section metrizamide-enhanced cisternography of three of the six PSP cases showed that the low-density abnormality was the result of the interpeduncular cistern invaginating the atrophic midbrain.

Aged↗
PubMedDate not supplied

Sonography of neonatal periventricular leukomalacia: recent experience with a 7.5-MHz scanner.

This study compared the relative efficacy of 5.0- and 7.5-MHz (high-resolution) transducers in the sonographic evaluation of cystic periventricular leukomalacia (PVL). Of 668 premature neonates evaluated by cranial sonography over a 4-year period, 34 were diagnosed as having PVL. Of these 34 neonates, 17 were examined with both 5.0- and 7.5-MHz transducers. Fifty-two neonates with no evidence of PVL also were evaluated by sonography with the two different-frequency transducers to determine the normal appearance of the neonatal brain. Among the neonates with PVL, features of the disease that have not been observed with routine 5.0-MHz transducers were apparent with use of the 7.5-MHz transducer: 7.5-MHz scanning clearly identified small areas of cystic PVL in three (17.6%) of 17 neonates that were not visible using the lower-resolution technique. The higher-resolution scanning also identified widening of the interhemispheric fissure by anechoic cerebrospinal fluid and demonstrated the falx as a distinct structure. The latter two superficial abnormalities were identified in combination with enlargement of the lateral and third ventricles, suggesting that diffuse cerebral atrophy accompanies PVL in most cases. The excellent near-field resolution of 7.5-MHz technology makes it the preferred method for the evaluation of PVL in the preterm neonate.

Atrophy↗
PubMedDate not supplied

CT of the brain in taste and smell dysfunction.

Three hundred fifty-four patients with taste and/or smell disorders were evaluated with computed tomography (CT). The largest group was characterized by head trauma (27%), followed by idiopathic causes (26%), postinfluenza-like hyposmia and hypogeusia (15%), and congenital etiologies (14%). Hyposmia and hypogeusia occurred concomitantly in 21%-45%, the percentage varying according to etiologic subgroup. CT abnormalities were found in 108 (31%) of the 354 patients. The most frequent pathologies were frontal encephalomalacia, subfrontal atrophy in the region of the olfactory bulbs, and anterior temporal lobe atrophy. These changes were found alone or in tandem. Some CT findings suggest common cerebral taste and smell centers and common neural pathways and association centers.

Ageusia↗
PubMedDate not supplied

Intracranial hemorrhage in neonates with erythroblastosis fetalis: sonographic and CT findings.

Cranial sonography revealed cerebral hemorrhage in three of seven neonates with erythroblastosis fetalis. Among the three infants with hemorrhage, one was 28 weeks gestational age and experienced germinal matrix hemorrhage with ventricular extension, a finding typical of cerebroventricular hemorrhage in the premature population. The other two infants with intracranial hemorrhage were more gestationally mature, and extensive intraparenchymal cerebral hemorrhages were found at sonography. These hematomas were peripheral in location and one was multifocal. Computed tomography (CT) further revealed hemorrhages in both neonates to be multifocal and in close proximity to the pia-arachnoid. In one case, the hemorrhage appeared to extend centripetally and rupture into the ventricular system. The high incidence, severity, and unusual appearance of intracranial hemorrhages in neonates with erythroblastosis fetalis has not been previously emphasized in the radiologic literature. In severe cases, children with erythroblastosis fetalis should be closely observed for intracranial hemorrhage by either sonography or CT, regardless of gestational age.

Cerebral Hemorrhage↗
PubMedDate not supplied

Cystic periventricular leukomalacia: sonographic and CT findings.

Periventricular leukoencephalopathy (PVL) is a pathologic process that has attracted little attention in neurodiagnosis. It is the second most common acquired central nervous system abnormality in neonates, outranked only by germinal matrix hemorrhage. Autopsy series suggest a 7%-22% incidence, but clinical recognition is poor. The diagnosis usually signals a less favorable neurodevelopmental outcome. Twenty-one cases with PVL and later cavitation (cystic PVL) were reviewed. Sonography was compared with computed tomography (CT) where applicable. In this series 4.8% of all neonates referred from an intensive care nursery developed cystic PVL. Hemorrhagic and nonhemorrhagic forms were observed. Sonography depicted both forms as strong periventricular echoes. Small cysts developed in the subacute phase. CT was unreliable in diagnosing the nonhemorrhagic form of PVL and had a tendency to miss the development of white-matter cysts. Sonography proved to be an excellent method for establishing the initial diagnosis and recognizing late sequelae. Late CT changes consisted of periventricular cysts, irregularity of the ventricular wall, ventricular enlargement, and cerebral atrophy.

Brain Diseases↗
PubMedDate not supplied

Cerebral intraparenchymal hemorrhage in neonates: sonographic appearance.

The real time sonographic findings of five neonates with cerebral intraparenchymal hemorrhage are reported. In each case, areas of markedly increased echogenicity corresponded to the site of hemorrhage. Excellent correlation was found between computed tomography (CT) and sonography. Although the sonographic appearance of intraparenchymal hemorrhage is characteristic, it is difficult to separate blood from other contiguous highly reflective structures in the head, including choroid plexus, bone, and the tentorium. It appears that real time sonography may offer an alternative to CT in the diagnosis of cerebroventricular hemorrhage in neonates.

Cerebral Hemorrhage↗