Biomedical subjects
H D Curtin
Publications and source records attributed to H D Curtin.
Cranial base surgery: results in 183 patients.
OBJECTIVE: To learn about the effects of cranial base surgery. DESIGN: Cohort study with a mean follow-up of 30 months. SETTING: Population-based. PATIENTS: A consecutive sample of 183 patients who underwent cranial base surgery; 118 patients had malignant skull base tumors, the majority of which were previously treated; 50 had benign tumors; 9 had congenital malformations of the skull base; 3 had inflammatory lesions, and 3 had traumatic defects of the skull base. MAIN OUTCOME MEASURES: Disease-free interval, overall survival, and rate of complications and functional status. INTERVENTION: Cranial base surgery was followed by radiotherapy (in previously untreated patients). RESULTS: After completion of follow-up (mean, 30 months), 30 (25.4%) patients had died of their malignant tumors and 8 (6.8%) had died of other causes. One patient (0.84%) was lost to follow-up. The overall cancer survival rate without regard to histologic type was 67% (63% with no evidence of disease). Among the patients who were treated for benign neoplasm, 72% had no evidence of disease at a mean follow-up of 39 months. The group of patients with congenital malformations and inflammatory and traumatic lesions demonstrated successful correction of their presurgical problem with skull base surgery. One patient (who had invasive aspergillosis) died of disease. The overall surgical-medical mortality rate was 2%; the complication rate was 33%, and the Karnofsky performance score was improved or unchanged after surgery in 83% of patients. The average duration of surgery, number of blood transfusions used, and length of the hospital stay were 10 hours, 3 units, and 15 days, respectively. CONCLUSIONS: Cranial base surgery is a valid surgical technique for treatment of cranial base afflictions. In this study it was found to be beneficial in controlling benign and malignant disease and to be the treatment of choice for selected congenital malformations, trauma, and inflammatory lesions.
Imaging of ossicular prostheses.
The prostheses available for reconstruction of the ossicular chain have expanded to include a variety of synthetic materials. Hydroxyapatite contains the inorganic constituents found in human living bone and is currently being incorporated into many new prostheses. This study demonstrates the computed tomography and magnetic resonance image characteristics of eight middle ear prostheses, a block of dense hydroxyapatite, and a human incus. Imaging of ossicular prostheses is more informative with computed tomography.
Inflammatory lesions and tumors of the nasal cavities and paranasal sinuses with skull base involvement.
The size and location of these masses can be accurately assessed today with appropriate imaging studies. The radiologist, however, must pay attention to detail and carefully evaluate the margins of the lesion and note its precise size because this information determines the operation and operative approach used. In addition, by carefully analyzing the imaging characteristics, a fairly accurate preoperative diagnosis can be given that will allow treatment planning to precede until final pathologic confirmation is available.
Double mucocele of the paranasal sinuses.
We have observed two contiguous mucoceles in one patient. Based on the mucoceles' signal intensities on MR imaging, as well as their anatomic location as delineated by CT and MR, we hypothesize that the "downstream" mucocele obstructed the "upstream" sinus, leading to formation of a secondary mucocele.
Fast spin-echo imaging of the neck: comparison with conventional spin-echo, utility of fat suppression, and evaluation of tissue contrast characteristics.
PURPOSE: To determine whether fast spin-echo sequences could replace conventional spin-echo methods in the evaluation of head and neck neoplasms and associated adenopathy and to evaluate differences in tissue contrast characteristics between conventional spin-echo and fast spin-echo examinations of head and neck disease. METHODS: Twenty-seven patients with squamous cell carcinoma were imaged on a 1.5-T imager with both conventional spin-echo and fast spin-echo sequences with identical section thickness and position. Twenty-one of the 27 fast spin-echo studies were performed with frequency-selective fat suppression. Three radiologists independently evaluated the images using a five-point scale to compare primary lesion margin definition and conspicuity, lymph node margin definition and conspicuity, gross motion artifact, and flow artifact. Quantitative percent contrast and contrast-to-noise ratios were calculated and compared in 7 cases with fat-suppressed fast spin-echo. RESULTS: Fast spin-echo was preferred by all three readers for lesion margin conspicuity and lymph node conspicuity. Gross motion and flow artifact demonstrated trends toward reader preference for fast spin-echo. Quantitative contrast values for fast spin-echo were significantly greater than those for conventional spin-echo. CONCLUSIONS: Fast spin-echo with fat suppression can replace conventional spin-echo at a time savings of more than 50% and improves tissue contrast and the conspicuity and definition of margins for primary lesions and lymph nodes. Fat-suppression heterogeneity remains the major limitation of this technique. Thus, careful attention to fat-suppression failure and unwanted water saturation is essential.
Radiology of congenital hearing loss.
Thin-section high-resolution computed tomography with "bone algorithm" remains the examination of choice for evaluation of congenital ear malformations. It furnishes the best anatomic detail for planning the surgical approach and avoiding unfortunate intraoperative events secondary to variant courses of vessels and nerves.
Subperiosteal orbital abscess in children: diagnosis, microbiology, and management.
A chart review was undertaken of 30 patients who were presented to Children's Hospital of Pittsburgh from 1983 to 1990 and underwent surgical management for suspected subperiosteal abscess of the orbit (SPA). All patients had preoperative computerized tomography (CT) scans. Twenty-seven of 30 CT scans were reevaluated, of which 20 (74%) demonstrated findings consistent with or suggestive of SPA. Opacified sinuses were seen in 100% of this study group. Abscess collections were found in 21 patients (70%). Predominant organisms included: Streptococcus pneumoniae (38%), Streptococcus pyogenes (33%), and Haemophilus influenzae (14%); Moraxella catarrhalis was not isolated and anaerobic bacteria were isolated from only one patient. CT scans were found to be accurate predictors of SPA in 16 (80%) of 20 patients. All patients did well following surgical intervention without visual or central nervous system sequelae. We conclude from this study that CT scans should be obtained when SPA is suspected, and antimicrobial therapy should be directed toward the bacteria isolated from these abscesses.
Chronic inflammatory sinonasal diseases including fungal infections. The role of imaging.
The computed tomographic (CT) and magnetic resonance (MR) imaging techniques used for evaluating the paranasal sinuses and nasal fossae are reviewed. A summary of the physics concepts relating to the MR signal intensities observed with sinonasal secretions is given, as is a review of normal secretions and the pathophysiologic changes in the secretions that occur with chronic infections. The imaging findings of sinonasal chronic infections, mucoceles, fungal diseases, and granulomatous diseases are then presented, and a recommended imaging protocol is given.
Magnetic resonance imaging of the large vestibular aqueduct.
The large vestibular aqueduct syndrome describes an abnormally large endolymphatic duct and sac with associated sensorineural hearing loss. This entity was originally reported in 1978 and has since been identified as a finding in children with progressive hearing loss. The original description of the large vestibular aqueduct employed hypocycloidal polytomography of temporal bone. Subsequent reports studied patients identified with this syndrome using computed tomographic scans. We report magnetic resonance imaging of two patients diagnosed with the large vestibular aqueduct syndrome. The magnetic resonance imaging and computed tomographic scans are compared and the significant findings on magnetic resonance imaging are reviewed. This should assist the otolaryngologist and radiologist with establishing the appropriate diagnosis.
Variability in the enhancement of the normal central skull base in children.
We studied the signal and enhancement characteristics of the central skull base prospectively in 40 children aged 13 days to 8 years, on a 1.5 T MRI system. Identical standard short TR/TE spin echo sequences in the sagittal plane were performed before and after intravenous gadolinium-DTPA. The sequences used for comparison were filmed at identical window and level settings. Three independent observers assessed (1) the intensity of contrast enhancement of the basisphenoid, basiocciput and presphenoid, (2) the signal intensity of the spheno-occipital synchondrosis, (3) the degree of pneumatization of the sphenoid sinus and (4) the uniformity of signal intensity reflecting fatty replacement of the marrow of the basisphenoid, basiocciput and presphenoid. In 16% and 28% respectively of cases there was no enhancement of the basisphenoid and basiocciput after gadolinium administration; in 42% and 44% there was mild enhancement, and moderate or intense enhancement was observed in 42% and 28% of cases. Even when there was irregular fatty replacement, residual hemopoietic clements could enhance intensely. When skull base neoplasms are being investigated, the normal signal irregularity and enhancement of the central skull base in children must not be confused with pathologic invasion of the marrow.
Three-dimensional computed tomography.
Three-dimensional images were generated by reformating data from an axial image set. Separate contours were generated for bone and for tumor. The contour representing the tumor was generated by tracing the tumor using a cursor on the CRT. The contours showed the relationship of the tumor to the skull base. Three-dimensional imaging by this method is more of a communication tool than a diagnostic tool. The information on such images can be derived from close analysis of the axial image set. Indeed, determination of the position of the tumor relative to very precise structures requires analysis of the original images. The three-dimensional imaging does orient the observer and give an overall view of the position of the tumor. Because the contour of the tumor is traced, the final image represents the opinion of the radiologist. Various technical considerations and artifacts are discussed.
Chondrosarcomas of the skull base: MR imaging features.
The magnetic resonance (MR) images from 17 patients with chondrosarcomas of the skull base were retrospectively reviewed to characterize the size, location, signal intensity, and extension of these tumors. Eleven patients with chondrosarcomas received intravenously administered gadopentetate dimeglumine. In 16 patients, computed tomographic (CT) scans were obtained to evaluate intratumorous mineralization and bone erosion. On short repetition time (TR)/echo time (TE) MR images, chondrosarcomas generally had low to intermediate signal intensity; on long TR/TE MR images, they generally had very high signal intensity. Signal heterogeneity on long TR/TE MR images was seen in 10 of 17 tumors (59%) and was caused by matrix mineralization, fibrocartilaginous elements, or both. Matrix mineralization was demonstrated with CT in seven of the 16 chondrosarcomas. Chondrosarcomas showed marked enhancement after administration of gadopentetate dimeglumine in either a heterogeneous (n = 8) or homogeneous (n = 3) pattern. The information about the size and extent of these neoplasms was important in the choice of surgical approaches for gross total resection of tumor.
Imaging of acoustic neuromas.
A negative high-quality, high-resolution, contrast-enhanced MRI scan is excellent evidence that a patient does not have an AN. Most nerve sheath tumors have a characteristic appearance, and when a tumor is detected there is seldom any doubt as to the identity of the lesion. There are other causes of enhancement, however, or of high signal that can be mistaken for an AN, and these must be kept in mind when a case is considered positive. In some cases, it may be appropriate to defer surgery to clarify a questionable finding by obtaining a follow-up scan. CT is still a reliable examination. In addition to evaluating the IAC, valuable information about the architecture of the petrous bone and labyrinth is provided. Improvements in imaging technology are occurring at a rapid rate. Thinner slices and more rapid scan techniques will make MRI even more useful in evaluation of the IAC.
Sphenochoanal polyps: evaluation with CT and MR imaging.
A sphenochoanal polyp is a solitary mass of low attenuation on computed tomographic (CT) scans that arises from the sphenoid sinus and extends through the sphenoid ostium, across the sphenoethmoid recess, and into the choana (the boundary between the nasal cavity and nasopharynx). More often, however, a choanal polyp is an antrochoanal polyp, which arises from the maxillary antrum, protrudes through the middle meatus, extends into the nasal cavity, and continues back to the choana. Contiguous axial or coronal magnetic resonance and CT images help clearly differentiate the rare sphenochoanal polyp from the more common antrochoanal polyp. The sinus of origin is important to identify, as the surgical approach depends on the target sinus.
Dehiscent temporomandibular joint.
The appearance of an acute effusion in a well-pneumatized temporal bone directs attention to the nasopharynx and skull base. Two patients are described in whom dehiscence of the temporomandibular joint allowed herniation of the contents of the joint posteromedically, where they obstructed the middle ear entrance of the eustachian tube, the protympanum. This is, to the authors' knowledge, a previously unreported cause of an acute middle ear and mastoid effusion.
The role of preoperative CT scans in staging external auditory meatus carcinoma: radiologic-pathologic correlation study.
Survival is related to the pathologic extent of tumor in external auditory meatus (EAM) carcinoma. This study assesses the validity of preoperative CT scans in staging EAM carcinoma. The accuracy of staging EAM carcinoma with preoperative CT scans was evaluated by comparing radiography and histopathology. Patients who received preoperative CT scan were selected from a retrospective series of 35 temporal bone resections for EAM squamous cell carcinoma. The CT scans were systematically reviewed for tumor involvement in 12 anatomic areas. The histopathology slides for the corresponding patients were reviewed according to the same criteria. CT scan findings accurately diagnosed the extent of tumor involvement identified during histopathologic examination. These tumors demonstrated the capacity to spread along existing anatomic pathways as well as direct bone erosion. We conclude that preoperative CT scans accurately stage EAM squamous cell carcinoma.
Computerized tomography and magnetic resonance imaging following cranial base surgery.
The computed tomography scans and magnetic resonance imaging films of 57 patients who underwent anterior or anterolateral cranial base surgery from January 1987 to August 1989 were retrospectively reviewed to ascertain the significance of early and late postoperative intracranial imaging changes. Extra-axial changes (air, blood, cerebrospinal fluid collection) were found in 96% of patients; axial changes (brain edema, contusion) were seen in 30% of patients in the first postoperative period (72 hours). Subsequently, extra-axial changes began to resolve but axial changes became more prevalent. After 6 months, only axial changes persisted (encephalomalacia). It was encouraging to find a low correlation of imaging abnormalities with clinically significant findings.