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Biomedical subjects

L A Hayman

Publications and source records attributed to L A Hayman.

At least 19 recordsLinked to original sources
PubMed2001

Surgical anatomy of the temporal bone: an atlas.

This atlas demonstrates the usefulness of reconstructed high-resolution CT for planning temporal bone surgery. The first part focuses on a sagittal plane, the second on a rotated longitudinal plane, and the third on a rotated transverse plane. We believe knowledge of temporal bone anatomy in these planes facilitates surgical planning by showing anatomic relationships and providing a customized map for each patient. This decreases the likelihood of surgical mishap and improves teaching.

Anatomy, Artistic↗
PubMed2001

Use of reconstructed sagittal computed tomography images to plan middle cranial fossa surgery.

OBJECTIVE: To facilitate planning in temporal bone surgery for the middle cranial fossa approach by using sagittal reconstructed temporal bone computed tomography images. STUDY DESIGN: Comparison of anatomic measurements on random high-resolution, reformatted computed tomography scans of the temporal bone. METHODS: High-resolution computed tomography of 10 normal temporal bones in the axial and coronal planes was obtained, and two-dimensional sagittal reconstructions were performed using a commercial software program. Eight anatomical relationships between neural and/or vascular structures were measured. Representative images were inverted to recreate the plane of the middle cranial fossa approach. RESULTS: Anatomical relationships among the vestibule, superior semicircular canal, internal auditory canal, internal carotid artery, and middle cranial fossa exhibited a high SD in the 10 subjects. The sample size and the large range for the eight anatomical relationships precluded the detection of a significant difference between right and left temporal bones or sex and age of the patient. CONCLUSION: The present report presents a novel, practical measurement protocol for rapidly evaluating important individual anatomical differences in patients before middle cranial fossa surgery. Inverted sagittal reconstructions facilitate presurgical planning for the middle cranial fossa approach by 1) assessing critical anatomical relationships before surgery and 2) providing customized measurements between vital landmarks and the first in vivo measurements. This decreases the likelihood of surgical mishaps and improves teaching by providing the first in vivo measurements of practical anatomical relationships in the sagittal plane.

Adult↗
PubMed2000

Triple-dose contrast-enhanced images in neurologically symptomatic HIV-positive patients.

Our purpose was to determine whether triple-dose delayed contrast-enhanced images would improve lesion detection in patients with symptomatic human immunodeficiency virus (HIV) infection. We reviewed 33 MRI studies on 29 patients. Single-dose immediate T1-weighted spin-echo (1x-T1) images were compared with delayed triple-dose images (D3x-T1). Two neuroradiologists decided which technique showed more lesions, increased lesion conspicuity and/or altered the radiologic diagnosis. The D3x-T1 technique improved lesion detection in 14 of 29 patients (48%). In two patients (7%), the improvement changed the radiologic diagnosis by showing new meningeal lesions.

Adult↗
PubMed2000

In vivo measurements of temporal bone on reconstructed clinical high-resolution computed tomography scans.

PURPOSE: To retrospectively assess the accuracy of measurements of temporal bone anatomy made from reconstructed clinical high-resolution computed tomography (HRCT) scans. METHODS: Nine HRCT scans were performed on unselected clinical cases in which the subjects had a temporal bone study judged to be normal. The orbitomeatal line was prescribed for the direct axial sections. Variations in head position (rotation at the neck and lateral bending of the neck) were corrected by using the software supplied by the manufacturer. All measurements were done on standard 1-mm axial sections and axial reconstructions obtained from 1-mm coronal slices. The images were viewed at 4000 Hounsfield units (HU) window width and 1000 HU window level. Measurements (n = 3) made on 1-mm direct axial HRCT scans were compared with the measurements made on reconstructed axial HRCT images from the same nine patients. These values were also compared with published cadaver data. RESULTS: The measurements obtained from axial reconstructed and direct HRCT series approximated each other in each of the nine individual studies and also fell within the range of published cadaver values. They demonstrated the expected normal temporal bone variability between individuals. CONCLUSION: Useful anatomic approximations can be measured in vivo from reconstructed clinical HRCT images. Pitfalls are improper window settings, head tilt, and rotation. This protocol is widely available and can be implemented retrospectively from clinical HRCT scans.

Adult↗
PubMed2000

Functional neuroanatomy of the frontal lobe circuits.

This article summarizes the current theories regarding the locations and functions of the three primary frontal lobe circuits. It forms the framework for structuring functional magnetic resonance imaging investigations. It can be used to assist in (a) detecting subtle lesions of the frontal circuits and (b) applying the current theories of neuropsychiatry to assess prognosis and to plan rehabilitation.

Brain Diseases↗
PubMed1999

Spinal disease in neurologically symptomatic HIV-positive patients.

We review the MRI findings of human immunodeficiency virus (HIV)-positive patients with "spinal" symptoms and review the literature. In 23 consecutive HIV-positive patients presenting with acute neurologic complaints thought to be referable to the spine, we reviewed spinal MRI, medical charts, and laboratory, pathologic, and autopsy data. In the early stages of HIV infection, the common causes of spinal complaints (i. e., degenerative spine and disc disease) predominated. However, pathology may be missed without contrast-enhanced MRI of the spine. In more advanced cases, the differential diagnosis includes one or more neoplastic and/or infectious causes which require contrast-enhanced MRI for detection. In these cases, normal cerebrospinal fluid findings should not preclude contrast-enhanced MRI of the spine. Imaging of the brain may also be indicated in cases when the spinal study is negative.

AIDS-Related Opportunistic Infections↗
PubMed1999

Conservative management of extra-axial hematomas diagnosed by CT.

Our purpose was to assess the role of serial CT in recently traumatized patients with clinically stable extra-axial intracranial hematomas (EACH) and a midline shift of less than 0.5 cm. A retrospective review of 91 imaging studies in 41 patients (with 45 EACH) was done to assess the time between trauma and CT; the presence and type of skull fracture; the volume, type, and location of the EACH; the presence of associated edema and/or contusion. Over a 19-day follow-up, 11% of the dense EACH increased in volume and 27% decreased. An adjacent skull fracture was seen most frequently in patients with a decrease in EACH volume. Clinical data remain the key to determining the need for neurosurgical intervention in patients with EACH. Follow-up CT afforded no data which altered the medical management of these patients. However, it may be said to have alerted the clinician to an increase in the size of the EACH in 11% of cases, which could mandate close observation of this group.

Adolescent↗
PubMed1999

Hyperechoic foci in the thalamic region imaged via the posterior fontanelle: a potential mimic of thalamic pathology.

BACKGROUND: We have incidentally noted foci of increased thalamic echogenicity (FITE) on cranial sonographic images obtained via the posterior fontanelle (PF) that were not confirmed on images obtained while scanning through the anterior fontanelle (AF). Therefore, we postulated that this is a normal variant of PF imaging rather than true thalamic pathology. OBJECTIVE: The purpose of this study was to determine the incidence of FITE detected on posterior and anterior fontanelle images. MATERIALS AND METHODS: Parasagittal images were obtained bilaterally through the trigone of the lateral ventricles (including the thalami) via both the anterior and posterior fontanelles in 15 consecutive neonates (30 thalami) and evaluated independently by two pediatric radiologists for the presence or absence of FITE. Thalami were graded as grade 0 (no FITE), grade 1 (possible FITE), or grade 2 (definite FITE). Follow-up CT (n = 3) and MR (n = 1) were reviewed. RESULTS: FITE were absent in 87 % of thalami imaged via the AF, and possible FITE were present in 13 % of these cases. No cases of definite FITE were identified via the AF. However, possible FITE were identified in 33-40 % of thalami and definite FITE were seen in 33 % of thalami imaged via the PF. CONCLUSIONS: FITE seen only on images obtained through the PF on cranial sonography are a normal finding and should not be attributed to thalamic hemorrhage or ischemia.

Cerebral Hemorrhage↗
PubMed1998

Klüver-Bucy syndrome after bilateral selective damage of amygdala and its cortical connections.

Isolated symmetric damage to the amygdala and their cortical connections occurred in an individual following cancer treatment. The lesions were imaged after reversal of hyponatremia. The patient displayed marked behavioral changes including visual agnosia, hypersexuality, hyperorality, a tendency to react to every visual stimulus, and memory deficits. The cluster of neurobehavioral symptoms is similar to previously reported accounts of Klüver-Bucy syndrome and suggests the importance of bilateral amygdala involvement in these behavioral changes.

Adult↗
PubMed1998

Postnatal maturation of the sacrum and coccyx: MR imaging, helical CT, and conventional radiography.

OBJECTIVE: The purpose of this paper is to provide a detailed radiologic description of the postnatal developmental anatomy of the sacrum and coccyx as revealed by MR imaging, helical CT, and conventional radiography. MATERIALS AND METHODS: One hundred ten imaging examinations of the sacrococcygeal spine were performed in patients who were newborn to 30 years old. Imaging included conventional radiography (n = 63), three-dimensional gradient-recalled echo MR imaging (n = 10), and helical CT with sagittal and angled coronal reformations (n = 37). A detailed analysis was performed of the ossification and fusion of the primary and secondary ossification centers. RESULTS: The sacrum and coccyx were noted to develop from 58 to 60 sacral ossification centers and eight coccygeal centers, respectively. These centers were noted to ossify and fuse in an organized temporal pattern from the fetal period to the age of 30. CONCLUSION: The sacrum and coccyx are formed by a complex process that fuses primary and secondary ossification centers. Because the maturation process can be asymmetric, an understanding of this process may prove useful for distinguishing physeal plates from fracture lines.

Adolescent↗
PubMed1998

The hippocampus: normal anatomy and pathology.

The hippocampus is a complex and fascinating region of the brain that has enormous clinical significance. Specifically, small imaging abnormalities may cause major symptoms. We believe that the detection of these lesions will be improved if imaging clinicians have an organized reference that facilitates identification of the cellular zones that comprise the hippocampus.

Adult↗
PubMed1998

Optimal imaging protocol after intraocular silicone oil tamponade.

PURPOSE: Our purpose was to define the optimal protocol for imaging of the orbits after vitreous humor replacement with silicone oil. METHODS: Eleven eyes in 10 patients with tractional and/or rhegmatogenous retinal detachment were studied. Five CT scans and 18 high-field (1.5 T) MR images were obtained. Standard T1-weighted, T1-weighted with fat and silicone saturation, fast spin density-weighted, and T2-weighted orbital MR sequences were performed. Unique pulse sequences included fast spin density-weighted and T2-weighted imaging with and without fat saturation or silicone saturation, gradient-echo imaging, and short-tau inversion recovery imaging. RESULTS: The T1-weighted MR and CT studies were comparable in displaying the silicone. However, the fat- or silicone-saturated fast T2-weighted sequences always showed the fibrous bands and subretinal fluid to best advantage. In one case, the eye also contained inadvertently retained perfluorocarbon liquid, which blended with silicone oil on both saturated images, requiring companion T1-weighted sequences without saturation to demonstrate its presence. CONCLUSION: Simple, commonly available fat-saturated fast T2-weighted MR images supplemented by standard T1-weighted images are all that are needed to evaluate the eye efficiently after vitrectomy and tamponade.

Adult↗
PubMed1998

In vivo CT and MR appearance of prosthetic intraocular lens.

PURPOSE: We present the first in vivo CT and MR imaging description of intraocular lenses (IOLs), which are commonly encountered in elderly patients who have undergone cataract surgery. METHODS: A retrospective review was done of the imaging studies of 20 patients (22 eyes) with IOLs and of three patients (four eyes) with aphakia. CT and MR studies were performed with standard clinical protocols. RESULTS: Sixteen patients with 18 posterior IOLs underwent six CT and 43 MR studies. Four patients with four anterior IOLs had one CT and eight MR studies. The exact position of the optic portion of the IOL could be optimally determined on CT scans with 1-mm-thick sections and on fat-saturated fast T2-weighted MR orbital coil studies performed on a 1.5-T imager. The haptics could not be distinguished from the ciliary body. Three patients with aphakia had eight MR and two CT studies. Aphakia was difficult to identify if the image thickness was greater than the diameter of the pupil (2.5 to 4.0 mm). CONCLUSION: The optic portion of an IOL is visible on either high-quality CT or MR studies. However, the haptic portion is not visible on clinical in vivo images.

Aphakia↗
PubMed1997

Imaging the temporal fossa.

OBJECTIVE: The purpose of our study was to delineate the interconnections in the temporal fossa that are visible on high-resolution clinical images. SUBJECTS AND METHODS: Thin-section MR images and CT scans of the temporal fossa in two normal volunteers were obtained in coronal and axial sections. MR images, CT scans, or both of 20 patients with demonstrable spread of disease were reviewed. RESULTS: The imaging studies of patients with disease proved more informative than images of the normal subject or the published anatomic and surgical descriptions of the temporal fossa. We recognized five discrete radiographically defined regions: the connective tissue layer, compartment of the superficial fat pad, compartment of the deep fat pad, compartment of the temporal muscle (superior recess of the suprazygomatic masticator), and subperiosteal zone. Important, tortuous, and to our knowledge undescribed interconnections between the scalp, posterior neck, eyelid, face, and the suprazygomatic masticator were delineated. CONCLUSION: Imaging studies of the temporal fossa can be used to formulate a clinically useful approach that simplifies the complex anatomy of the temporal fossa.

Adipose Tissue↗