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Biomedical subjects

M F Mafee

Publications and source records attributed to M F Mafee.

At least 91 records · Page 5Linked to original sources
PubMed1988

Diagnostic imaging techniques in thyroid cancer.

With the refinement of fine-needle aspiration, the specific applications of thyroid imaging techniques need to be reevaluated for efficiency and cost containment. No thyroid imaging test should be routinely obtained. Radionuclide scanning is most beneficial in evaluating the functional status of thyroid nodules when fine-needle aspiration is inadequate, the findings are benign, or when there is no discrete nodule that is palpated in an enlarged gland. When fine-needle aspiration is unavailable or unreliable, radionuclide scanning becomes a first-line diagnostic tool. Ultrasonography should be used primarily for identifying a solid component of a cystic nodule, determining the size of nodules on thyroxine suppression that are not easily palpable, or for performing guided fine-needle aspiration. Computerized tomography and magnetic resonance imaging both have a definite role in the evaluation of thyroid tumors. Magnetic resonance imaging is superior to computerized tomography for the evaluation of metastatic, retrotracheal, or mediastinal involvement of large thyroid tumors or goiters. Careful selection of the diagnostic techniques will ensure more accurate diagnosis and reduce unnecessary patient costs in the treatment of thyroid cancer.

Biopsy, Needle↗
PubMed1988

Choroidal hematoma and effusion: evaluation with MR imaging.

To evaluate the usefulness of magnetic resonance (MR) imagining in the evaluation of choroidal pathologic conditions, the authors studied 15 patients with either choroidal hematoma or choroidal effusion with a 1.5-T MR imager. These two lesions were reliably distinguished from each other on the basis of MR findings. Choroidal hematomas appeared as lenticular-shaped masses in the wall of the eyeball, and signal intensity depended on the age of the hematoma. Choroidal effusions appeared as crescentic or ring-shaped areas of increased signal on both T1- and T2-weighted images in an anatomic distribution corresponding to the choroidal and suprachoroidal spaces.

Adult↗
PubMed1988

Direct sagittal CT in the evaluation of temporal bone disease.

The human temporal bone is an extremely complex structure. Direct axial and coronal CT sections are quite satisfactory for imaging the anatomy of the temporal bone; however, many relationships of the normal and pathologic anatomic detail of the temporal bone are better seen with direct sagittal CT sections. The sagittal projection is of interest to surgeons, as it has the advantage of following the plane of surgical approach. This article describes the advantages of using direct sagittal sections for studying various diseases of the temporal bone. The CT sections were obtained with the aid of a new head holder added to our GE CT 9800 scanner. The direct sagittal projection was found to be extremely useful for evaluating diseases involving the vertical segment of the facial nerve canal, vestibular aqueduct, tegmen tympani, sigmoid sinus plate, sinodural angle, carotid canal, jugular fossa, external auditory canal, middle ear cavity, infra- and supralabyrinthine air cells, and temporomandibular joint.

Adolescent↗
PubMed1988

Tumors and tumor-like conditions of the middle ear and mastoid: role of CT and MRI. An analysis of 100 cases.

CT and MRI scanning provide valuable information in determining location and extension of middle ear and mastoid tumors and tumor-like conditions. The bone anatomy depicted by CT better delineates the involvement of the middle ear diseases. In glomus tumors, facial nerve tumors, and other cases including temporal bone metastases, the combination of CT and MR imaging is exceedingly useful in the diagnosis and management of patients.

Cranial Nerve Neoplasms↗
PubMed1988

MRI and in vivo proton spectroscopy of the lesions of the globe.

MRI proved very valuable in the diagnosis of intraocular lesions. In this report, uveal melanomas, the most common intraocular tumors in adults, were seen as hyperintense lesions on T1W and PW images and as hypointense lesions on T2W images. MRI is not accurate for diagnosis when the melanoma is smaller than 3 mm. Associated retinal detachment as well as necrotic or hemorrhagic changes within the uveal melanoma can be identified by MRI. Choroidal metastasis may be difficult to differentiate from uveal melanoma. Choroidal hemangioma and hematoma often can be differentiated from uveal melanoma. Early experience with in vivo proton MR spectroscopy has the potential for obtaining biochemical information, thus enhancing the diagnostic sensitivity of MR studies. Future work on combined MRI with MR in vivo spectroscopy is needed to characterize abnormal conditions according to their patterns and for identification of tumor markers. A differential diagnosis list for ocular (globe) lesions can be found in the introduction to this issue. A discussion of the majority of the ocular lesions listed can be found in either this article or the article on congenital/pediatric lesions (Hopper et al) of the orbit, also in this issue.

Diagnosis, Differential↗
PubMed1988

Central vestibulocochlear pathology: role of MRI and CT.

Hearing loss, tinnitus, dizziness and disequilibrium are frequent complaints of patients with labyrinthine and retrolabyrinthine lesions. The objective of a neurotological examination is to establish the presence and location of a lesion, whether it is labyrinthine (cochlear or vestibular) or intracranial. On the basis of neurotological and vestibular results, provided by neurotologist or otolaryngologist, if a retrocochlear or retrovestibular lesion is suspected, a magnetic resonance imaging (MRI) or computed tomography (CT) study of the head is obtained with particular attention to the acoustic nerve and posterior fossa. MR and CT are exceedingly helpful to identify the extraaxial and intra-axial lesions involving the vestibulocochlear nerves and their central pathways. The appearances on MR and CT scans of varied pathological entities involving the central vestibulocochlear pathways are reviewed and illustrated.

Cochlear Nerve↗
PubMed1988

Otogenic intracranial inflammations: role of CT.

This article reviews the authors' results using CT in the diagnosis of 18 selected patients who were clinically suspected of having otogenic intracranial complications, demonstrating with illustrative examples the important role of CT in diagnosing various stages of acute coalescent mastoiditis and its associated complications.

Adolescent↗
PubMed1988

Cholesteatoma of the middle ear and mastoid. A comparison of CT scan and operative findings.

High-resolution CT scanning accurately depicts the status of the structures of the temporal bone, allowing delineation of pathology prior to surgical exploration of ears with cholesteatoma. It provides information concerning location and extent of disease as well as possible anatomic variations and complications that may be encountered. The main advantages of CT scanning over polytomography are superior soft-tissue contrast resolution and improved spatial detail at a reduced radiation dose for the patient.

Bone Diseases↗
PubMed1988

Head and neck: high field magnetic resonance imaging versus computed tomography.

A comparative review of head and neck lesions examined with both CT and MRI showed that the location and extent of lesions can be more precisely evaluated with MRI. MRI allows better differentiation of neurogenic tumors from other lesions. Vascular structures are easily visualized on MRI without intravenous contrast and can easily be differentiated from lymph nodes. However, cystic lesions and necrotic nodes sometimes could not be differentiated from solid lesions when using MRI.

Branchioma↗
PubMed1988

Temporomandibular joint: role of direct sagittal CT air-contrast arthrogram and MRI.

Direct sagittal CT air-contrast arthrography can provide useful diagnostic information in the evaluation of disorders of the temporomandibular joint. The technique for the performance of this examination is practical and efficient, using a specifically designed head-holder, which is described. This technique effectively complements the clinical and imaging work-up of jaw dysfunction.

Adult↗
PubMed1987

Magnetic resonance imaging and intraocular foreign bodies.

We conducted in vitro and in vivo experiments to study magnetic resonance imaging of intraocular foreign bodies. Diamagnetic and paramagnetic foreign bodies were imaged without artifact and without movement during the imaging process, while ferromagnetic foreign bodies produced large amounts of artifact that prevented meaningful images. All fetromagnetic foreign bodies moved during in vitro imaging. During in vivo imaging, three of four ferromagnetic bodies moved, producing substantial retinal injury. We concluded that magnetic resonance imaging is contraindicated in traumatized eyes with suspected ferromagnetic foreign bodies.

Animals↗
PubMed1987

CT evaluation of TMJ disc replacement with a Proplast-Teflon laminate.

A series of 12 temporomandibular joints treated by discectomy and replacement with Proplast nonporous Teflon laminates were examined retrospectively using direct sagittal and coronal computed tomography. Radiographic findings included severe condylar, glenoid fossa, and eminence remodeling changes; implant migration and fragmentation; and loss of implant adaptation to the temporal bone. The radiographic changes generally occurred in patients who were completely asymptomatic clinically.

Adult↗
PubMed1987

Magnetic resonance imaging in the evaluation and differentiation of uveal melanoma.

We evaluated 39 patients with intraocular disease by magnetic resonance imaging (MRI). Malignant uveal melanoma was considered the likely diagnosis in 25 patients. Seventeen patients underwent surgery, and the histopathologic diagnosis of melanoma was confirmed. The authors observed that uveal melanomas had characteristic MRI features consisting of a relatively high-signal intensity in T1-weighted images and a relatively low-signal intensity in T2-weighted images. These images reflected their inherently relative short T1 and T2 relaxation times. Choroidal lesions elevated more than 3 mm were well visualized on MRIs. MRI also proved valuable for differentiating uveal melanoma from associated subretinal effusion, choroidal hemangioma, choroidal metastasis, and hemorrhagic and serous choroidal detachments.

Adult↗
PubMed1987

Magnetic resonance imaging of central nervous system defects in Usher's syndrome.

With the use of magnetic resonance imaging, seven patients with type II Usher's syndrome were evaluated for CNS defects. The goals of this study were to confirm the presence of CNS defects previously detected by computed tomography (CT) scans in patients with Usher's syndrome while seeking additional anatomic defects in the posterior fossa employing a potentially more sensitive procedure using magnetic resonance imaging. Findings of CNS lesions in both the midbrain (high-signal-intensity lesions) and the cerebellum (vermian atrophy) necessitate further characterization of these defects in terms of their progressive nature and clinical significance for patients with Usher's syndrome.

Adult↗