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Biomedical subjects

W N Hanafee

Publications and source records attributed to W N Hanafee.

At least 19 recordsLinked to original sources
PubMed1992

Computed tomography versus standard radiography in the assessment of fractures of the mandible.

Twenty-nine fractures of the mandible were studied by standard radiographs and axial computed tomographic scans (hard copy). Independent reviewers analyzed each study in a blinded, non-paired fashion. When radiographic diagnostic sensitivities were compared on the basis of known surgical findings, the plain films were found to have a higher diagnostic sensitivity (89%) than the hard copy computed tomograms (64%). This difference occurred primarily with images of nondisplaced fractures in posterior portions of the mandible, and is likely the result of tomographic orientation and volume averaging. Though computed tomography has emerged as the standard diagnostic test in evaluating intracranial and maxillofacial trauma, this study demonstrates that computed tomographic scanning alone is inadequate in excluding nondisplaced fractures of the posterior mandible.

Fracture Fixation, Internal↗
PubMed1991

Meckel cave lesions: percutaneous fine-needle-aspiration biopsy cytology.

The authors describe the novel combination of two traditional methods to facilitate diagnosis of Meckel cave lesions, which may otherwise require craniotomy to obtain adequate tissue samples. Fine-needle-aspiration biopsy cytology was performed on tissue obtained with a percutaneous approach via the foramen ovale with use of fluoroscopic guidance and intravenous analgesia during an outpatient procedure. This new application of fine-needle-aspiration biopsy cytology results in decreased patient morbidity and significant cost reduction.

Adult↗
PubMed1991

Nonneoplastic enhancing lesions mimicking intracanalicular acoustic neuroma on gadolinium-enhanced MR images.

The authors describe five patients with nonneoplastic lesions of the facial and/or vestibulocochlear nerves that demonstrated focal enhancement within the internal auditory canal on magnetic resonance (MR) images. MR and surgical findings for four patients with unilateral sensorineural hearing loss and one with Ramsay Hunt syndrome were reviewed. Three patients with hearing loss underwent surgical exploration and decompression of the internal auditory canal. The MR findings in all four patients with hearing loss were similar: Focal enhancement of the internal auditory canal was depicted on postcontrast T1-weighted images. Nonneoplastic lesions of the seventh and eighth cranial nerves may show focal enhancement on MR images, which mimics the appearance of a small intracanalicular neuroma. This potential for misdiagnosis may have important therapeutic implications.

Cranial Nerve Diseases↗
PubMed1990

Advances in medical imaging.

The field of medical imaging, stimulated by advances in digital and communication technologies, has grown tremendously. New imaging techniques that reveal greater anatomical detail are available in most diagnostic radiology departments. We discuss vascular imaging with ultrasound, high-resolution computed tomography of the thorax, magnetic resonance imaging applications, and picture archiving and communication systems. Vascular imaging with ultrasound requires duplex and color flow Doppler, which combine gray-scale ultrasound and the Doppler phenomenon. High-resolution computed tomography modifies conventional computed tomography technology and results in images with higher spatial resolution. Magnetic resonance imaging applications for all areas of the body are being investigated and are replacing older roentgenographic techniques such as computed tomography, arthrography, myelography, and even angiography in a growing number of indications. With these new digital imaging modalities, image management has become an important consideration that can be addressed by picture archiving and communication systems.

Diagnostic Imaging↗
PubMed1990

Evaluation of mandibular tumor invasion with magnetic resonance imaging.

Evaluating the extent of tumor invasion of the mandible is clinically important in the management of mandibular tumors. Conventional imaging studies including panoramic radiography, bone scans, and computed tomography, as well as clinical evaluation can be unreliable in defining the extent of neoplastic marrow invasion. This study presents the initial UCLA, Los Angeles, Calif, experience with magnetic resonance imaging in evaluating mandibular invasion by benign and malignant neoplasms. Magnetic resonance imaging, using T1 and T2 images, was compared with conventional imaging methods in 11 patients with malignant lesions and nine patients with benign lesions. In all cases, magnetic resonance imaging most accurately determined the full extent of tumor invasion in the mandibular marrow spaces. Magnetic resonance imaging appears to be superior to offer clear benefits over conventional imaging methods, including computed tomography, for the evaluation of tumor invasion of the mandible.

Adult↗
PubMed1990

Magnetic resonance imaging of the tongue and oropharynx.

In general, MRI produces superior soft tissue detail in evaluating the tongue and oropharynx than does CT. MRI is therefore considered the study of choice in this area. Lack of artifact from dental amalgam and beam hardening artifact from the mandible on MRI also eliminates two major shortcomings of CT in the examination of this area. Finally, the ability of MRI to obtain direct coronal and sagittal scan planes is a distinct advantage in recognizing intrinsic tongue musculature and assessing tumor volume and spread for treatment planning.

Carcinoma, Squamous Cell↗
PubMed1990

Magnetic resonance imaging of the larynx.

The development of appropriate surface coils has resulted in outstanding depiction of the laryngeal anatomy using MRI. The multiplanar capability of MR allows superior definition of anatomy and tumor extent compared with CT scanning. MR appears to be more effective in detecting cartilage invasion. MR is as effective as CT in defining adenopathy and extension into the carotid sheath. MRI is therefore the primary modality in imaging the larynx.

Carcinoma, Squamous Cell↗
PubMed1990

Magnetic resonance imaging of metastatic cervical adenopathy.

Detecting cervical adenopathy is critical in the management of carcinomas in head and neck. CT scanning remains a very effective modality in defining adenopathy. T1-weighted MRI scans are comparable to CT in detecting lymph nodes. T2-weighted images are less useful as the lymph nodes tend to have long T2 relaxation times similar to the surrounding fat. MR has not proved to be useful in detecting carcinoma in non-enlarged cervical nodes. The morphologic criteria developed for metastatic nodes with CT are appropriate with MRI (size, shape, signal, extracapsular spread). Gadolinium is sometimes useful in defining central necrosis in metastatic squamous cell adenopathy.

Carcinoma, Squamous Cell↗
PubMed1990

Interventional magnetic resonance imaging in the head and neck.

Interventional MRI is clearly in its early stages of development. While the value of MR-guided aspiration cytology and MR evaluation of deep electrode implantation in the brain has already been confirmed with human clinical studies, the future of MR-guided interstitial laser therapy remains to be proven. Despite this, as we look ahead into the 1990s and the millennium, it is possible to imagine dedicated MR laser therapy units for combined radiological and surgical outpatient approaches in what may become the operating rooms of the 21st century.

Biopsy, Needle↗
PubMed1989

Magnetic resonance imaging of the facial nerve.

Magnetic resonance imaging (MRI) of the facial nerve was evaluated by studying normal volunteers and patients with diseases of the facial nerve with a 0.3 Tesla permanent-magnet MRI system with special surface coils. The normal MR images were correlated with the anatomy of thin cryosection specimens of fresh cadavers. The seventh nerve was followed from its nucleus in the brainstem through the temporal bone to the parotid gland bed. The entire labyrinth and tympanic portions, as well as the geniculate ganglion, could be shown with appropriate scan planes. Examples of brainstem diseases affecting the facial nerve and nucleus, facial neuromas, parotid tumors involving the facial nerve, and other diseases were studied. MRI is a technique that allows unique evaluation of the entire course of the facial nerve. It produces superior images of the facial nerve with high-contrast resolution. Unlike computed tomography, there is no beam-hardening artifact from the temporal bone or exposure to ionizing radiation and contrast agents. MRI also allows visualization of the main trunks of the facial nerve in the parotid bed not possible with any other imaging technique.

Facial Nerve↗
PubMed1989

Magnetic resonance imaging of the larynx.

Rarely does any radiologic imaging modality play a significant role in reaching a diagnosis of malignancy in the larynx and hypopharynx. These regions are so readily accessible to clinical examination that the combination of cytology and visual inspection usually strongly indicates the diagnosis of cancer. Therefore, the primary role of MR is the same as that of CT in imaging the larynx and hypopharynx: to define the extent of the disease. Compared to CT, MR consistently shows superior soft tissue definition. The use of direct coronal and sagittal scan planes allows the visualization of intrinsic laryngeal musculature in addition to better defining cranial caudal tumor extension. Thus, MR is now the imaging study of choice for the evaluation of cancer of the larynx. The role of MR can also be extended to replace CT scanning in the evaluation of the laryngeal airway and benign lesions of the larynx.

Glottis↗
PubMed1989

The role of gadolinium-DTPA in the evaluation of extracranial head and neck mass lesions.

Based on our experience with 28 patients, there is good evidence that gadolinium-enhanced MR will be useful in evaluation of skull base involvement, sinus involvement, or intracranial extension by neoplasms that involve the neck above the hard palate. This region has historically been a difficult area to image with any modality, because of the detailed anatomy and numerous important structures that traverse it. Gadolinium-enhanced MR should provide a valuable tool in the evaluation and management of these patients. The evidence that gadolinium is useful in staging of primary and nodal squamous cell carcinoma of the extracranial head and neck is less apparent. Areas where gadolinium may be helpful include size and extent of primary tumor and internal architecture of nodes that do not meet size criteria for malignant adenopathy. This is an area in which more experience is necessary, employing careful correlation with enhanced CT, unenhanced MR, and surgical specimens. Posttreatment follow-up of head and neck squamous cell lesions is a potential use for gadolinium, but this too is yet to be adequately studied. We have found that gadolinium enhancement provides no additional information important to the management of benign head and neck lesions over enhanced CT or unenhanced MR.

Carcinoma, Squamous Cell↗
PubMed1989

MR-directed needle biopsies.

New generation stainless steel alloys have enabled the development of needles which can be used for MR-guided biopsies. Biopsy under MR guidance has the advantages of greater tissue contrast resolution, lack of ionizing radiation, and variable angle oblique imaging planes. The biopsy approaches and imaging techniques are described.

Adult↗
PubMed1987

Parotid masses: MR imaging.

Over a 2-year period 20 patients who presented with masses in the parotid gland were evaluated with magnetic resonance (MR) imaging. T1-weighted images were obtained on a high-resolution, thin-section MR imaging system. When "cystic-appearing" lesions were found, T2-weighted images were obtained in order to better characterize the tumor. As in other areas of the body, MR images of parotid tumors are not usually histologically specific. MR findings may be distinctive in rare cases and define the internal architecture of complex parotid masses. Although poor tumor margination was a clue to malignancy, this was not a consistent finding. The real advantage of MR imaging in evaluating parotid masses was its ability to accurately reveal the extraparotid or intraparotid location of a tumor and demonstrate the relationship of the tumor to the facial nerve. Small and medium-sized mass lesions could be seen as superficial or deep to the facial nerve. Larger masses producing some distortion of the normal course of the nerve made identification of the nerve more difficult, if not impossible. In malignant tumors with gross invasion of the facial canal, MR images can show the extent of nerve involvement.

Cadaver↗
PubMed1987

Asymptomatic degenerative disk disease and spondylosis of the cervical spine: MR imaging.

Evidence on magnetic resonance (MR) images of disk degeneration and herniation, as well as of cord and root impingement, may be regarded either as normal, age-related changes or as causative of symptoms. Individuals referred for MR examinations of the larynx without symptoms referable to the cervical spine were studied retrospectively (35 patients) or prospectively (65 patients) over a 2-year period. With a solenoid surface coil, 5-mm-thick sections were acquired in sagittal, axial, and coronal planes with T1-weighted spin-echo pulsing sequences. Disk protrusion (herniation/bulge) was seen in five of 25 (20%) patients aged 45-54 and 24 of 42 (57%) patients older than 64 years of age. Posterolateral protrusions were seen in only nine of 100 patients and occurred with greatest frequency in patients over 64 years of age. In no patient was obliteration of the intraforaminal fat seen. Spinal cord impingement was observed in nine of 58 (16%) patients under 64 years of age, and in 11 of 42 (26%) patients over 64 years of age. Cord compression was observed in seven of 100 patients and occurred solely secondary to disk protrusion in all cases. The percentage of cord area reduction never exceeded 16% and averaged approximately 7%.

Aged↗
PubMed1987

MR imaging of the nasopharynx and floor of the middle cranial fossa. Part I. Normal anatomy.

The normal anatomy of the nasopharynx and floor of the middle cranial fossa was analyzed with magnetic resonance (MR) imaging. MR images from five healthy volunteers were correlated with whole-organ cryomicrotome sections from three cadavers. Anatomic connections exist between the paranasopharyngeal spaces and the surface structures of the skull base. These anatomic connections include the intimate relationship between the eustachian tube and the pharyngobasilar fascia, the attachment of the muscles of mastication and deglutition to the skull base, and vascular and nervous structures in the foramina. The inherent contrast between the soft tissues of the nasopharynx and related structures and the bone of the floor of the middle cranial fossa allowed excellent visualization of these anatomic connections.

Cadaver↗