Biomedical subjects
Publications and source records attributed to G L Popky.
Radiology plays a key role in the diagnosis and treatment of renal inflammatory diseases. The efficacious use of the various imaging modalities in evaluating renal inflammatory disease requires knowledge of their attributes as well as their weaknesses. We review the available studies and use of contrast agents, and illustrate radiologic findings in specific inflammatory disease processes.
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Nineteen patients with complex partial seizures refractory to medical treatment were examined with routine electroencephalography (EEG), video EEG monitoring, computed tomography or magnetic resonance imaging, neuropsychological tests and interictal single photon emission computed tomography (SPECT) with I-123 iodoamphetamine (INT). In 18 patients, SPECT identified areas of focal reduction in tracer uptake that correlated with the epileptogenic focus identified on the EEG. In addition, SPECT disclosed other areas of neurologic dysfunction as elicited on neuropsychological tests. Thus, IMP SPECT is a useful tool for localizing epileptogenic foci and their associated dynamic deficits.
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.
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.
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.
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.
While conventional angiography has been used to demonstrate cerebrovascular occlusive disease in the past, digital subtraction angiography (DSA) is capable of showing progressive vascular involvement with ease, simplicity, and extremely low morbidity, making it particularly well suited for children and outpatients either alone or coordinated with computed tomography. The authors discuss the usefulness and advantages of DSA as demonstrated in 7 infants and children with hemiplegia, 4 of whom had sickle-cell disease.
A prospective study in 47 patients was undertaken to determine which of the two major sites for injection of contrast material, superior vena cava or antecubital vein, produces digital subtraction images of higher quality. Both injection sites were used to obtain images of the carotid and aortic arch areas in each patient. The two injection sites were also compared for ease of performance of the study, patient acceptance, and incidence of complications and motion artifacts. It was determined that the degree of vessel conspicuity is not affected by injection site when equal volumes of contrast material are injected. No significant differences in overall image quality attributable to injection site were found, except for carotid images obtained in the anteroposterior projection; for these images, the antecubital vein injection site produced significantly better images. Vessel conspicuity was not the major determinant of overall image quality as judged by radiologists.
A prospective study of 6,527 hospitalized patients was performed to evaluate the effectiveness of multivariate analysis of risk factors to correctly designate risk for pulmonary embolism. History of previous pulmonary embolism was the single most important factor. In patients without prior history, five factors emerged: inactivity, congestive heart failure, Doppler ultrasound evidence of deep-vein occlusion, female sex, and black race. Used together, these factors permitted a discrimination of risk such that 68.7% of pulmonary embolization was found to occur in 32.2% of the population designated as showing increased risk. Multivariate analysis of clinical factors improved assessment of risk, compared to the use of lower extremity findings alone, and proved to be useful in identifying individuals at increased risk for pulmonary embolism.