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Biomedical subjects

W N Hanafee

Publications and source records attributed to W N Hanafee.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1987

MR imaging of the nasopharynx and floor of the middle cranial fossa. Part II. Malignant tumors.

The intracranial extension of tumors of the nasopharynx and related spaces presents a difficult imaging problem. Unlike computed tomography (CT) scans, magnetic resonance (MR) images are not limited by beam-hardening artifacts from bone or dental amalgam. Forty-six patients with malignant tumors of the nasopharynx and related spaces affecting the skull base underwent MR imaging. MR images were obtained with a 0.3-T permanent-magnet imaging system in axial, sagittal, and coronal planes. MR findings were compared with clinical records, plain radiographs, CT scans, and pathologic correlates when available. MR imaging could demonstrate neoplastic invasion of the bone of the floor of the middle cranial fossa and the vital soft-tissue structures related to it as well as or better than CT. Tumor extension was viewed directly as a continuous mass or indirectly by marrow replacement or displacement of normal structures. Specific anatomic routes through which tumors extend from the nasopharynx to the middle cranial fossa were inferred from MR findings.

Eustachian Tube↗
PubMed1987

Magnetic resonance imaging of the larynx and tongue base: clinical applications.

The use of surface coils on subjects, and internal engineering improvements have combined to greatly improve the signal-to-noise ratio on the magnetic resonance imager at our institution over the past two and one-half years. This has resulted in a marked improvement in image resolution, as well as reduction in the time required and related cost of these studies. Magnetic resonance (MR) examinations at our institution now cost less than comparable computed tomography (CT) studies. This article summarizes our experiences in imaging the larynx and tongue base. Eleven cases are presented to illustrate how the direct multiplane capacity of MRs and their increased soft tissue contrast provide some definite advantages over CT in determination of extent of disease in these regions.

Aged↗
PubMed1987

MR imaging of the intraparotid facial nerve: normal anatomy and pathology.

Three normal volunteers, 58 normal patients, and three patients with parotid tumors were studied with a 0.3 T permanent-magnet imaging system to directly image the intraparotid facial nerve. On T1-weighted images the nerve appeared as a curvilinear structure of relatively low signal intensity within the fatty, high-signal parotid parenchyma. Its major divisions and branches could be imaged only with specially angled axial scan planes. To verify our observations MR imaging was compared with whole-organ cryomicrotome sections cut at the same angles. Normal variations in the appearance of the nerve and pitfalls in its visualization are discussed. Three cases of parotid tumors, with surgical confirmation of the relationship of the facial nerve to the tumor, are presented. MR is the only imaging technique capable of direct imaging of the facial nerve in the parotid bed: it may assist materially in the surgical management of tumors of the parotid gland.

Adult↗
PubMed1986

Magnetic resonance imaging artifacts: mechanism and clinical significance.

Many types of artifacts may occur in magnetic resonance imaging. These artifacts may be related to extrinsic factors such as patient motion or metallic artifacts; they may be due specifically to the MR system such as power gradient drop off and chemical shift artifacts; they may occur as a consequence of general image processing techniques, as in the case of truncation artifacts and aliasing. Change in patient position, pulse sequence, or other imaging variables may improve some artifacts. Although reduction of some artifacts may require a service engineer, the radiologist has the responsibility to recognize MR imaging problems. The radiologist's knowledge of MR imaging artifacts is important to the continued maintenance of high image quality and is essential if one is to avoid confusing artifactual appearances with pathology.

Diagnostic Errors↗
PubMed1986

Larynx and hypopharynx: MR imaging with surface coils.

Forty patients with disorders of the larynx or hypopharynx were studied with magnetic resonance (MR) imaging. Axial, coronal, and sagittal sections, 4 mm thick, were obtained. Twenty-eight of the patients underwent computed tomography (CT) scanning; 17 underwent surgery, and specimens were obtained for organ sectioning. Correlation was made between these three studies as well as with clinical history, physical examination, and endoscopic photography. In 13 patients who underwent all three studies, the depiction of cartilage invasion, adenopathy, and intraorgan and extraorgan spread of disease was compared. MR consistently showed superior soft-tissue definition and extent of disease compared with CT. Neither CT nor MR was able to depict histologic detail or microscopic spread of disease. Both studies were also less effective in the postoperative or postirradiated neck. The use of direct coronal and sagittal imaging planes on MR allowed the visualization of intrinsic laryngeal musculature, which was important in the recognition of subtle tumor extension. For these reasons, surface coil MR imaging is currently the imaging study of choice at our institution for disorders of the larynx and hypopharynx.

Carcinoma, Squamous Cell↗
PubMed1986

Head and neck MR imaging in the pediatric patient.

Magnetic resonance (MR) imaging studies of the head and neck (excluding the brain) were obtained in 49 children believed to have lesions of the head and neck. Seven children had normal images; in the remaining 42, lesions were divided into four categories: midline lesions, lesions of symmetric paired structures, facial lesions, and nasopharyngeal and oropharyngeal lesions. All entities were well delineated by MR imaging. The imaging planes and sequences chosen depended on the suspected abnormality. Midline lesions were best imaged in the sagittal plane, lesions of paired structures and the face in the axial or coronal planes, and nasopharyngeal and oropharyngeal lesions in the axial or sagittal planes. Intracranial extension of head and neck neoplasms was best evaluated in the coronal plane. Surface coils provided better resolution and were thus more useful in evaluating small superficial lesions; head or body coils were more useful in defining the extent of large lesions. T2-weighted images provided better differentiation between normal and tumor tissue in patients with head and neck neoplasms.

Adolescent↗
PubMed1986

Tongue and oropharynx: findings on MR imaging.

Ten healthy subjects and 44 patients with diseases of the tongue or oropharynx were studied with magnetic resonance (MR) imaging. Axial, coronal, and sagittal images with a thickness of 4 mm were obtained with a pixel size of 0.75 X 0.75 mm on a 256 matrix. Nineteen of the patients underwent computed tomography (CT). Nine of those patients later had surgery, and the specimens were obtained for organ sectioning. These three studies as well as clinical history and physical examination findings were correlated. MR imaging was equal to or better than CT in those patients having both examinations. However, neither CT nor MR allowed recognition of histologic features or detection of microscopic spread of disease. Direct coronal and sagittal imaging planes on MR imaging allowed visualization of intrinsic tongue musculature, not possible with CT; this was important in recognizing subtle tumor extension. For these reasons, MR is the imaging method of choice for studying diseases of the tongue and oropharynx.

Adult↗
PubMed1986

Solenoid surface coils in magnetic resonance imaging.

A nonplanar solenoidal surface radiofrequency coil is used as a receiver with a conventional transmitter coil in a magnetic resonance imaging system. The improved signal-to-noise ratio, compared with that of conventional fixed saddle or solenoid receiver coils, permits higher resolution imaging and thinner image sections. In addition, the problem of signal dropoff that occurs in deep structures with planar and other noncircumferential surface coils is eliminated. Solenoid surface coils are particularly useful in imaging deep structures in anatomic regions that do not fit standard head and body coils, such as the neck, knees, and other smaller body parts.

Adult↗
PubMed1986

Boundary artifact due to truncation errors in MR imaging.

A boundary artifact in MR images due to truncation of the infinite Fourier series necessary to encode tissue discontinuities was investigated by using doped water phantoms and normal volunteers. All images were obtained on 0.3-T permanent and 0.6-T superconducting MR imagers with varying phase and frequency sampling rates. The artifact appeared in both the phase and frequency encoding direction as parallel lines or ringing adjacent to borders or tissue discontinuities. This was unlike motion artifacts, which occur predominantly in the phase direction, and chemical shift misregistration errors, which are most pronounced in the frequency direction. Increasing the sampling frequency from 128 to 512 resulted in higher frequency ringing and more rapid drop-off in amplitude. Low-pass digital filtering also decreased the ringing at the expense of fine detail. The truncation of the infinite Fourier series necessary to encode edges to the 128-512 terms used for most MR imaging produces the artifact. It is important to recognize this common artifact and not mistake it for patient motion or disease.

Diagnostic Errors↗
PubMed1985

The unprotected parasphenoidal carotid artery studied by high-resolution computed tomography.

A retrospective review was made of 500 consecutive thin-section axial CT scans of the adult sphenoid sinus using contrast enhancement and the bone algorithm to determine whether there was exposure of the cavernous sinus and the carotid arteries along their parasphenoidal course. At least one cavernous-carotid complex that could be considered at risk during sphenoid sinus surgery was seen in 31.4% of the patients. Of this group, 14.4% of the patients had no bony covering on one or both sides at some point along the parasphenoidal course. In 17% the bony covering was so thin it would give minimal, if any, protection from surgical trauma. A patient who had laceration of an unprotected carotid artery with development of post-traumatic aneurysm is discussed.

Aneurysm↗
PubMed1985

Application of surface coils to MR anatomy of the larynx.

The magnetic resonance (MR) scans of 10 patients with normal larynges were compared with cryomicrosections of two injected cadaver specimens. The MR images were obtained with a solenoid surface coil and high-resolution technique that provided images 4 mm thick displayed on a 256 X 256 matrix. The improved signal-to-noise ratio of the surface coil allowed a detailed study of normal anatomy in the axial, coronal, and sagittal planes.

Humans↗
PubMed1984

Laryngeal involvement in rheumatoid arthritis. A clinical, laryngoscopic, and computerized tomographic study.

Laryngeal involvement was evaluated in 45 patients with moderately severe rheumatoid arthritis (RA). RA duration and severity, prior laryngeal symptoms, and abnormalities detected by concurrent indirect laryngoscopy (IL) and computerized tomography (CT) were noted and correlated with changes of basilar interstitial fibrosis (BPF) found by chest radiograph. Thirty-two percent had abnormalities detected by IL, 54% had abnormalities by CT, and 36% had BPF on chest radiographs. Comparison of these groups revealed: only two symptoms (sore throat and difficulty during inspiration) were predictive of abnormalities detected by IL; no symptoms predicted abnormalities on percentage of RA patients even in the absence of symptoms; IL tends to detect mucosal and gross functional abnormalities while CT detects structural lesions; BPF shown on chest radiographs in RA patients does not appear to be correlated with cricoarytenoid arthritis as defined by IL and CT.

Adult↗
PubMed1984

Computed tomography of macroglossia secondary to amyloidosis.

Computed tomography of the tongue base and floor of the mouth is an effective means for evaluating and characterizing deep lingual masses. We report two cases of macroglossia secondary to amyloidosis. The findings at CT and differential diagnosis are discussed.

Aged↗
PubMed1984

Branchial cleft anomalies and their mimics: computed tomographic evaluation.

A review was made of the clinical records and radiographic examinations of 38 patients with neck lesions clinically suspected of being branchial cleft anomalies. The impact of computed tomography in this sometimes confusing clinical picture was assessed and CT criteria for diagnosing branchial cleft anomalies (BCAs) and differentiating them from their mimics were identified. Seventeen branchial cleft anomalies (four of the first branchial cleft and 13 of the second branchial cleft) and 21 BCA mimics were evaluated. A definitive CT diagnosis of second branchial cleft cysts based on characteristic morphology, location, and displacement of surrounding structures was possible in 80% of cases. CT was found to be the best radiographic examination in making a definitive diagnosis of BCA if a neck mass was present. CT-derived information, by providing additional preoperative data on the extent and type of neck lesion, frequently altered the course of patient management.

Adolescent↗