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Biomedical subjects

A N Hasso

Publications and source records attributed to A N Hasso.

At least 37 records · Page 2Linked to original sources
PubMed1996

Basilar and distal vertebral artery occlusive disease: correlation of MR imaging and MR angiography.

The purpose of this study is to evaluate the correlation of brain lesions seen on magnetic resonance imaging with vascular occlusive disease of the basilar and distal vertebral arteries as documented on MR angiography. The clinical findings are also correlated with the findings on MR imaging and MR angiography. The clinical records of twenty-one patients with proven occlusive disease of the distal vertebral and/or basilar arteries were retrospectively reviewed. All the patients were imaged utilizing either the Siemens Magnetom 1.5 T SP 4000 and the Siemens 1.0 T Impact systems. Dual MR angiographic techniques were employed including two-dimensional (2D) and three-dimensional time-of-flight. The 2D sequences utilized fast low angle shot gradient echo sequences. The 3D sequences utilized fast image steady-state precession gradient echo sequences. Gadolinium contrast was utilized for increased angiographic detail in one patient. Magnetization transfer contrast was used in three patients. The individual partitions as well as the maximum intensity pixel projection images were evaluated in each case. The most extensive brain lesions were seen in the group of patients with severe basilar and/or combined vertebrobasilar disease. One-half of these patients showed non-specific scattered foci of T2 lengthening similar to the findings found in a group of patients with noncritical stenosis. MR imaging invariably demonstrated more lesions than were clinically suspected. Even though the brain lesions tended to be more extensive in patients with severe vascular disease, the amount of brain tissue damage was not an adequate parameter to document the degree of vascular narrowing. The degree of vascular narrowing was useful in therapy planning. Such data was obtained by the MR angiograms, but not by MR imaging. MR angiography is a useful complementary examination when lesions in the basilar and distal vertebral vascular territories are diagnosed on MR imaging. MR angiography can differentiate critical from noncritical stenosis and can thus play a key role in the therapeutic decision making process.

Adult↗
PubMed1996

Magnetic resonance imaging of cranial nerve VII.

Magnetic resonance imaging (MRI) is well suited for the evaluation of lesions of the seventh cranial (facial) nerve. The preferred MRI approach requires use of multiplanar thin sections of the full course of the nerve from the pons through to its terminal branches on the face. The use of paramagnetic contrast greatly increases the sensitivity of MRI and for the most part precludes the need to use computed tomography scans in conjunction with the MRI scans.

Cranial Nerve Neoplasms↗
PubMed1994

Magnetic resonance imaging of the paranasal sinuses and nasal cavities.

Magnetic resonance imaging has proven to be a useful tool for imaging the paranasal sinuses and nasal cavities. Of particular interest in this region is the ability to distinguish between lesions that are highly cellular with little free water (neoplasms) and lesions that have significant amounts of serous and mucinous secretions and thus contain predominantly free water (infections).

Humans↗
PubMed1994

Magnetic resonance imaging of the pharynx and larynx.

Imaging of the pharynx and larynx has been a difficult challenge for many years. The advent of magnetic resonance imaging (MRI) with its superior soft tissue contrast resolution and multiplanar capabilities has allowed the imaging specialist to examine these structures with unparalleled precision. The recent developments in MRI can also aid the oncologist, surgeon, and radiation therapist in developing a more comprehensive treatment plan for patients with pharyngeal and laryngeal neoplasms. This article describes the important advances in MRI of the pharynx and larynx.

Humans↗
PubMed1994

Magnetic resonance imaging of the oral cavity and tongue.

The oral cavity is the oral portion of the upper aerodigestive tract separated from the oropharynx by the soft palate, anterior tonsillar pillars, and circumvallate papillae. The anatomy of the components of the oral cavity, including the oral tongue, the floor of the mouth, the retromolar trigone, the hard and soft palates, the buccal mucosa, and the gingiva, are described. The pathology discussion includes both malignant (predominantly squamous cell carcinomas) and benign disease entities commonly detected in this region.

Humans↗
PubMed1994

Magnetic resonance imaging of soft tissues of the neck.

Magnetic resonance imaging (MRI) has proven to be an ideal examination for evaluating a variety of soft tissue lesions in the extracranial head and neck. In this article we will describe the MRI characteristics of a variety of the soft tissue lesions found in the neck. Pathophysiology, clinical presentation, treatment, and prognosis are also discussed.

Head and Neck Neoplasms↗
PubMed1994

Cerebral ischemia and infarction.

Cerebral infarction is most commonly related to atherosclerotic disease in the carotid and vertebrobasilar circulations. TIAs are manifestations of this same disease process and may occur before a complete infarction. The transformation of pale to hemorrhagic infarction may result from reperfusion of an infarct or from migration of an embolus. CT is often the primary imaging study to exclude frank hemorrhage. The use of MR is increasing, in both the acute and the subacute phases of stroke. The combination of MR imaging and MR angiography is gradually replacing CT, particularly in patients with TIAs. In addition, the depiction of minute alterations in contrast and subtle mass effect is visualized with MR more often than with CT. The precise localization of brain stem and posterior fossa infarctions is improved by the ability of MR to view complex structures in two or more orthogonal planes. Vascular structures are readily identified both on the spin echo images and with MR angiography. Slow or obstructed flow in the venous channels may be recognized, which makes MR the ideal examination for the evaluation of cerebral ischemia and infarction.

Brain Ischemia↗
PubMed1994

Intracranial vascular malformations.

Magnetic resonance imaging is a useful process in the evaluation and follow-up examination of intracranial vascular malformations. Magnetic resonance imaging as related to the four subtypes of these malformations, arteriovenous malformations, venous angiomas, cavernous malformations, and capillary telangiectasis, is discussed.

Adolescent↗
PubMed1994

Intracranial vascular tumors.

The study of intracranial vascular tumors is of significant importance because these tumors may stimulate vascular malformations, infarctions, or infections. This article describes vascular tumors and discusses their appearance on MR imaging studies. Choroid plexus neoplasms, primitive neuroectodermal tumors, hemangioblastoma and other disorders are discussed.

Adult↗
PubMed1994

Magnetic resonance imaging of the skull base.

Magnetic resonance (MR) imaging has made it possible to evaluate the skull base in one primary screening examination. In most cases, MR imaging also serves as the definitive imaging study. In some traumatic or congenital lesions or both, computed tomography (CT) and conventional radiographs may be preferred or may be needed to supplement the MR imaging examination. This article discusses the pathology of the skull base, particularly in the evaluation of suspected neoplasms. Optimal imaging of the skull base requires a minimum of two planes of section, typically with and without gadolinium contrast enhancement.

Bone Diseases↗
PubMed1994

Asymptomatic myositis ossificans of the medial pterygoid muscles: a case report.

Traumatic myositis ossificans, also known as myositis ossificans circumscripta or fibrodysplasia ossificans circumscripta, is a form of dystrophic calcification leading to heterotopic ossification of intramuscular connective tissue. This is usually due to a single severe injury or repeated minor injuries to muscle, although cases without a history of injury have been reported. Heterotopic ossification is rare in the orofacial region, especially in the medial pterygoid muscles. A case of medial pterygoid myositis ossificans with unique computed tomography findings is described.

Aged↗
PubMed1992

Effects of the interaction between ferric iron and L-dopa melanin on T1 and T2 relaxation times determined by magnetic resonance imaging.

T1 and T2 relaxation times of agar phantoms containing L-dopa melanin and Fe3+ were measured under MRI conditions. Fe3+ shortened T1 and T2 relaxation times. Melanin influenced relaxation times only in the presence of Fe3+; thus, contrast in MR images of the basal ganglia may depend upon levels of both paramagnetic iron and neuromelanin.

Basal Ganglia↗
PubMed1992

Fetal kleeblattschädel cranium: morphologic, radiographic, and histologic analysis.

The kleeblattschädel deformity is a rare craniofacial condition typified by its trilobed, cloverleaf skull. The pathophysiology of this process is controversial. The morphologic, radiographic, and histologic abnormalities identified in the cranial base of an 18-gestational-week fetus with kleeblattschädel skull have not been described previously. Recently, the intrauterine diagnosis of kleeblattschädel was established by serial ultrasonography and, based on this evidence, the fetus was aborted. The fetus was studied extensively. Standard radiographs and high-resolution CT scans were obtained. Three-dimensional, reformatted contour surface images were constructed from the CT scan data. The cranial base was examined grossly, radiographically, and histologically. Histologic microanatomic study concentrated on structures of the mid-sagittal cranial base from the occiput to the mid maxilla. The distorted cranial architecture in kleeblattschädel deformity has, in the past, been attributed largely to the cranial base deformity which secondarily distorts the developing brain. Our study, however, suggests that the calvarium itself may be the primary focus of abnormal events leading to synostosis. The findings in this study seem to be inconsistent with earlier theories about the abnormal development of craniodysostoses.

Adult↗
PubMed1992

Adult extra-axial brain tumors.

Magnetic resonance imaging is the preferred cross-sectional imaging study for the evaluation of nearly all extra-axial brain tumors in adults. This article outlines the neoplasms by their pathology. The discussion covers the neoplasms originating from central neuroglial cells, meninges, and cranial nerves. In addition, developmental tumors and cysts and secondary extra-axial tumors are discussed.

Adult↗