Biomedical subjects
Publications and source records attributed to J D Swartz.
Sixty-five mass lesions of parotid origin were evaluated using thin-section high-resolution computed tomography to ascertain histologic specificity. All patients were studied after infusion of intravenous contrast media. Factors judged included the extent of glandular involvement, invasion of adjacent soft tissues, degree of postcontrast computed tomography density (relative to muscle), and the presence of calcification.
Erosions of the ossicular chain that occurred as a complication of noncholesteatomatous chronic otitis media were studied with computed tomography (CT) in 55 patients. The incus (particularly the long and lenticular processes) was the ossicle most commonly involved (50 cases). Coronal and axial CT sections were complementary in the diagnosis of these erosions. Fibrous replacement of the incudostapedial articulation was diagnosed in four cases on axial CT scans when an unusually wide joint was present.
Twenty-two patients with synthetic ossicular replacements were studied with computed tomography (CT). Twelve patients had total ossicular replacement prostheses (TORPs), and ten patients had partial ossicular replacement prostheses (PORPs). Good results were achieved in 12 patients (eight with TORPs and four with PORPs). Four of these prostheses were clearly visible on CT scans, six were discernible, and two were not identified. In the ten patients with unsatisfactory surgical results, CT was performed before surgical revision. It disclosed subluxation of the prosthesis in four patients and fibrous tissue fixation in four. In two patients the CT scan appeared normal; surgery disclosed lateralization of the graft with a nonfunctioning interface.
Complete incus disarticulation may be a complication of trauma, chronic otitis, or prosthetic stapedectomy. Purposeful incus disarticulation (with incus interposition) is used as a method of ossicular reconstruction. CT has been a valuable diagnostic tool for preoperative location of the incus in the former disorders and for determination of the status of the ossiculoplasty in the latter.
The authors have encountered three unique neonates with global cerebral cortical ischemia. The pathogenesis and computed tomography scans of these patients who sustained profound hypoxemia is described. Follow-up computed tomography scans in each case demonstrated generalized loss of cortical substance.
We used computed tomography (CT) to evaluate 44 patients who had undergone stapedectomy with insertion of a prosthesis. Several patients had poor surgical results, including recurrent conductive hearing loss, vertigo, and sensorineural hearing loss. Conductive hearing loss occurring immediately after the procedure was most often caused by anatomic limitations or surgical technique. Causes of delayed or recurrent conductive hearing loss included reparative granuloma formation, incus necrosis (at the attachment of the wire), prosthesis subluxation (most often posterior), and regrowth of otosclerosis, which occasionally is further complicated by incus dislocation. We found that CT is often diagnostic when these complications occur. Immediate sensorineural hearing loss or vertigo can be self-limited if caused by serous labyrinthitis. When delayed, these symptoms may be due to perilymph fistula. If caused by the latter, CT may not yield abnormal findings unless subluxation of the prosthesis into the vestibule has occurred.
Computed tomography (CT) was used to study 25 patients with congenital conductive hearing loss and normal external auditory canals. Deformities were subdivided according to ossicular, fenestral, and cholesteatomatous origin. Isolated ossicular deformities were found in 14 patients (five bilateral), cholesteatoma in eight, oval-window nondevelopment (with ossicular deformity) in one, and normal studies in two (congenital stapes fixation at the level of the annular ligament). Ossicular deformities may be subdivided into incudostapedial disconnections into incudostapedial disconnections (most common), malleoincudal fixations, and stapes fixations. Most are due to developmental anomaly of the first or second branchial arch. The stapes has a dual origin (second arch and otic capsule). A cholesteatoma is defined as congenital only if there is no history of otitis and the tympanic membrane is intact. In this series, six were in the middle ear proper, and two were within the attic beyond otoscopic view. Their CT appearance, with one exception, was essentially identical to that of acquired lesions.
The CT signs of aberrant course of the internal carotid artery are presented and are contrasted against those of anomalously high jugular bulb, glomus tympanicum and cholesterol granuloma.
At our institution, computed tomography is the procedure of choice for evaluation of suspected mass lesions of the major salivary glands. It affords exact anatomic localization of a mass and allows simultaneous examination of the contralateral gland and other regional structures of importance in salivary gland disease. Intravenous contrast medium enhancement is always utilized; however, concomitant sialography has never been necessary. Regional anatomy of the salivary glands with respect to computed tomography imaging and clinical material demonstrating its efficacy are presented. The neoplastic and nonneoplastic diseases affecting the salivary glands are reviewed.
We have recently examined three young patients with congenital unilateral profound sensorineural hearing loss. On computed tomography the only abnormality discovered was a remarkably enlarged vestibular aqueduct on the abnormal side. The vestibular aqueduct syndrome is an important cause of congenital hearing loss. Although this finding has been well illustrated with conventional multidirectional tomography, there has been little emphasis on the computed tomographic appearance.
Postinflammatory ossicular fixation is a common problem encountered by the otologic surgeon upon exploration because of conductive hearing loss in patients with chronic otitis media. These nonotosclerotic noncongenital lesions take three pathologic forms: fibrous tissue fixation (chronic adhesive otitis media), hyalinization of collagen (tympanosclerosis), and new bone formation (fibro-osseous sclerosis). Fibrous tissue fixation appears on CT as nonbony, noncalcific soft-tissue debris encasing some or all of the ossicular chain. Tympanosclerosis appears as unifocal or multifocal punctate or weblike calcifications in the middle ear cavity or on the tympanic membrane. This debris may be in direct apposition to the ossicular chain or may replace the suspensory ligaments in symptomatic patients. New bone formation has been identified only in the attic and is the least common manifestation. Thick bony webs or generalized bony encasement may be present at CT. More than 300 patients with the clinical diagnosis of chronic otitis media have been examined. This study encompasses 23 proved cases.
Ninety patients who had suspected or confirmed fenestral or cochlear otosclerosis underwent CT examination. Foci of demineralization in the otic capsule were discovered in 20 ears (12 patients). Audiometric studies of the 12 patients revealed sensorineural hearing loss (SNHL) with distinct correlation of CT findings with progressivity and with involvement of the frequency level subtended by the specific area of the cochlea involved. Foci of abnormal increased density, presumably representing the healed phase of this disorder, were found less frequently than expected. There was a predilection for the basilar turn. All patients had static SNHL in the higher frequencies. The healed phase of this disorder is probably not consistently diagnosable with CT.
Ossification of the membranous labyrinth (labyrinthitis ossificans) develops as the final result of many inflammatory processes, for example, meningitis, blood-borne septic emboli, middle ear infection, and cholesteatoma. Labyrinthine ossification may also occur as a result of previous labyrinthectomy or secondary to trauma. Seven cases of labyrinthine ossification accompanied by severe vertigo and total hearing loss in the affected ear are discussed. The computed tomographic appearance of varying degrees of ossification, the clinical and surgical circumstances from which this disorder may develop, and the various approaches to labyrinthectomy are described.
The external auditory canal, middle ear, and bulk of the ossicular chain develop from the first branchial groove, first and second branchial arches, and first pharyngeal pouch. Embryologic development of these structures is complex and only rarely are two anomalies identical. Development of the inner ear structures occurs independently of external ear structures, and concomitant involvement is unusual. This study includes 11 cases of unilateral external auditory canal atresia and two cases of bilateral atresia. Eight cases (four bilateral) of isolated congenital ossicular anomalies are also included. Emphasis is placed on findings of surgical import. All patients were studied with computed tomography only, because it was believed that the bony and soft-tissue detail achieved is superior to that with conventional multidirectional tomography.
Dysplasias of the external auditory canal can be evaluated with high resolution CT using proper technique. Images are studied to determine the type of atresia (membranous or bony) and the thickness of the associated atretic plate (if present). Other findings sought include the degree of pneumatization, the status of the fenestrae, the size of the tympanic cavity, and the location of both the mandibular condyle and the facial nerve canal.
Computed tomography has replaced conventional multidirectional tomography in the imaging of patients with the presumed diagnosis of otosclerosis. In addition to obliterative disease, which was easily diagnosed with multidirectional tomography, anterior and posterior foci of varying sizes can now also be visualized preoperatively. Active cochlear otosclerosis (otospongiosis) is diagnosed in the presence of foci of demineralization in the otic capsule. Diagnosis of these entities has been of great interest to our referring otologic surgeons.
Prior to the availability of high-resolution computed tomography (CT), the mainstay of roentgenographic diagnosis of cholesteatoma was conventional filming and complex motion tomography. The precise extent of the soft-tissue mass was very difficult to delineate with these methods, and one relied on indirect findings such as bony erosion and displacement. With high-resolution CT, the soft-tissue mass itself can be seen. Typical modes of extention of pars flaccida cholesteatomas of varying size are illustrated in this study.
Normal and pathologic anatomy of the soft tissues of the neck is clearly delineated with high resolution computed tomography (CT). The CT densities of soft tissues, fat, and enhanced blood vessels are strikingly different from each other and, therefore, mass lesions are clearly discernable. Often, a histologic diagnosis may be suggested with a high level of confidence based on the location and tissue characteristics.