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Biomedical subjects

H D Curtin

Publications and source records attributed to H D Curtin.

At least 37 records · Page 2Linked to original sources
PubMed1998

Larynx.

The complex anatomy of the larynx, best conceptualized as a set of mucosal folds draped over a cartilaginous skeleton, has developed as a consequence of its many upper airway functions. Despite its deep location in the neck, much of the mucosal surface of the larynx is amenable to direct laryngoscopic inspection. The role of the radiologist in laryngeal imaging, therefore, is not primarily to diagnose disease, but to aid in both surgical staging and in the evaluation of potential clinical "blind spots." In this article, the normal anatomy of the larynx is reviewed, with special attention to important surgical and functional structures.

Humans↗
PubMed1998

Dental bur fragments causing metal artifacts on MR images.

PURPOSE: Our purpose was to define the role of dental bur fragments in producing metal artifacts on MR images. METHODS: Dental prosthetic reconstructions were made for two dogs. The two lower second premolars were prepared for full-cast crowns by using a diamond bur. The crown margin was placed subgingivally on the right side (1 mm below the free gingival margin) and at the same level as the free gingival margin on the left side. After 1 week, full-cast crowns were cemented in place. MR imaging was performed 7 days later. RESULTS: Metal artifacts appeared in both second premolar regions of the mandible on MR images, with the right side, in which the crown margin was positioned subgingivally, displaying a larger signal distortion than the left side. After removal of the crown, the artifact remained on the right. On histopathologic examination, bur fragments were detected in the gingiva, more on the right than on the left. X-ray fluorescent element analysis showed iron in the gingival tissue containing bur fragments. CONCLUSION: Distortion of MR images was considered to be attributable in part to the damage of the gingiva and in part to the presence of dental bur fragments.

Animals↗
PubMed1997

A re-evaluation of imaging criteria to assess aggressive masticator space tumors.

PURPOSE: To evaluate the correlation between the gross imaging evidence of an aggressive masticator space (MS) tumor and the presence of such a MS malignancy. MATERIALS AND METHODS: Thirty patients were identified retrospectively who had a malignancy that either arose in or metastasized to the MS, had pathologic verification of the diagnosis, and had magnetic resonance (MR) and/or computed tomographic (CT) images. Specifically evaluated was the presence or absence of gross imaging evidence of mandibular erosion and the integrity of the medial MS fascia as evaluated by a smooth margin between this fascia and the parapharyngeal space fat. RESULTS: Of the 30 tumors, 28 were high-grade malignancies and 2 were histiocytoses. Of these, 5 had mandibular erosion and violation of the MS fascia, 19 had bone erosion with an intact fascia, 4 had neither bone erosion nor fascial violation (3 of these patients were under the age of 20 years), and 2 had fascial violation with no bone erosion. CONCLUSIONS: In 76.7% of patients with a malignancy arising in the MS, on imaging the medial MS fascia was grossly intact. There were 4 patients with MS malignancy and neither violation of the medial MS fascia nor mandibular bone erosion. Thus, these imaging findings may not be good criteria to evaluate the presence of a high-grade MS malignancy, especially if the patient is under the age of 20 years, in which age group MS sarcomas are more likely to arise.

Adolescent↗
PubMed1997

Giant-cell tumors of the sphenoid bone in four children: radiological, clinical, and pathological findings.

We report the clinical pathological and radiological findings of giant cell tumor of the sphenoid bone in four children aged 10 to 16 years. The most common clinical finding was headache, followed by cranial nerve abnormalities. The computed tomographic findings of giant cell tumor consist of a lytic defect, sharply margmated with no sclerosis associated with an expansile, homogeneous mass (isodense with muscle). In the differential diagnosis, the lesion most similar to giant cell tumor is giant cell granuloma. The different histopathological features of the two lesions are discussed, along with other lesions, in the differential diagnosis. The magnetic resonance features consist of a mass with low signal intensities on T(1) and T(2) weighted images associated with moderate enhancement after introduction of gadolinium.

Journal Article↗
PubMed1996

Chondrosarcoma of the nasal septum: skull base imaging and clinicopathologic correlation.

Chondrosarcoma arising in the head and neck and craniofacial region is an uncommon lesion. The nasal septum is a particularly rare site of origin, with approximately 30 cases previously reported in the English literature. We present six new cases of chondrosarcoma arising in the nasal septum. Each of these tumors required cranial base surgical approaches for removal. Current imaging techniques allow a very accurate diagnosis to be made before biopsy. The characteristic ring-forming calcifications seen on computed tomography scans can be correlated with the histologic pattern of calcification. Magnetic resonance imaging techniques allow precise definition of tumor extent, which is particularly important because the disease is best treated with primary surgery. Advances in imaging and surgical techniques allow a much more complete tumor removal. It is hoped that this will increase the likelihood of cure in these patients. Surgical management and indications for adjuvant therapy are discussed.

Adult↗
PubMed1996

Applications of image-guided navigation in the middle cranial fossa: an anatomic study.

Determining the location of pertinent anatomic structures (ie, the internal auditory canal [IAC]) in middle cranial fossa surgery is commonly based on indirect inferences from bony landmarks. Several methods have been proposed for identification of the IAC, each using bony landmarks coupled with geometric formulation. Identification of the IAC based on bony architecture and geometry may be severely limited when a mass lesion is present. Image-guided surgery has the advantage of rapid localization and may be helpful in navigating a complex surgical field which has been distorted by tumor. This study evaluates the feasibility and accuracy of the ISG viewing wand in determining pertinent anatomic landmarks in the middle fossa of the human cadaver. High-resolution (1 mm) computed tomography was performed on a preserved human cadaver head in which fixed fiducial markers had been placed. Subsequently, the cadaver head was registered in a simulated operative field, and middle fossa craniotomy was performed. The foramen spinosum, foramen ovale, greater superficial petrosal nerve, internal carotid artery, arcuate eminence, and IAC were identified visually, and three independent localizations of each structure were performed with the viewing wand. Accurate localizations were consistently performed within 1 mm for each anatomic landmark. Image-guided navigation is both feasible and accurate in determining intraoperative landmarks in the middle fossa. Image-guidance may enhance surgical accuracy and efficiency. Further clinical studies evaluating image-guided techniques in the middle fossa are warranted.

Journal Article↗
PubMed1996

T2-weighted MR characteristics of internal auditory canal masses.

PURPOSE: To determine whether masses of the internal auditory canal are hypointense relative to cerebrospinal fluid, and therefore visible, on fast spin-echo T2-weighted MR images. METHODS: Forty-six patients had 50 masses of the internal auditory canal, identified initially on contrast-enhanced MR images, that were evaluated retrospectively for signal intensity of the mass with respect to cerebrospinal fluid and for visibility of the neural elements within the internal auditory canal on T2-weighted images. RESULTS: Forty-seven of 50 masses were clearly identified on T2-weighted images. Three small abnormalities (2 to 4 mm) were not seen with confidence on T2-weighted images. However, on close inspection of these three masses, the small abnormality on contrast-enhanced MR images corresponded to a hypointense focus on T2-weighted images. All 50 masses were hypointense relative to cerebrospinal fluid on T2-weighted images. CONCLUSION: All masses of the internal auditory canal in this study were hypointense relative to cerebrospinal fluid on T-2 weighted images, and were therefore visible.

Cohort Studies↗
PubMed1995

Practical Applications of Image-Guided Navigation during Anterior Craniofacial Resection.

Intraoperative image-guided navigation allows the surgeon to identify anatomic landmarks obscured by overlying normal tissue, neoplasms, infection, or previous surgery. This case presentation illustrates some of the practical applications of the ISG image-guided navigation system during anterior cranial base surgery. The advantages and the pitfalls of the ISG system are discussed.

Case Reports↗
PubMed1995

Necrotizing (malignant) external otitis: prospective comparison of CT and MR imaging in diagnosis and follow-up.

PURPOSE: To compare computed tomography (CT) and magnetic resonance (MR) imaging in the diagnosis and follow-up of necrotizing external otitis. MATERIALS AND METHODS: CT and MR imaging were performed in seven patients at diagnosis and at 6 and 12 months after initiation of therapy. Imaging findings were compared and correlated with the clinical course of the disease. RESULTS: Cortical bone erosion was best seen on CT scans (n = 5 vs n = 0 on MR images) and failed to normalize with cure. Subtemporal soft-tissue abnormalities (n = 7 with both modalities) were better appreciated with MR imaging and had low signal intensity on T1- and T2-weighted images. Soft-tissue changes improved but did not disappear completely with treatment. CONCLUSION: CT is preferred at initial diagnosis, as small cortical erosions are better seen. Either modality can be used to follow up soft-tissue evolution. MR imaging may be better for evaluation and follow-up of meningeal enhancement and changes within the osseous medullary cavity.

Aged↗
PubMed1995

Enlarged anterior chamber: CT finding of a ruptured globe.

A deep anterior chamber of the globe is a clinical sign of posterior scleral rupture, an ophthalmologic emergency. On axial CT, the depth of the anterior chambers of ruptured globes was greater than the depth of the anterior chambers of normal globes. The discrepancy between the depth of the two anterior chambers in any patient can also suggest posterior scleral rupture.

Anterior Chamber↗
PubMed1995

The petrous apex.

Petrous apex lesions are rare, but when present, they can usually be precisely defined. The key to their identity consists of answering five questions: 1) Is the abnormality arising in the petrous apex or from contiguous areas? 2) Are the bony walls of the apex and the septations in the air cells smoothly remodeled? 3) What are the MR imaging signal characteristics of the lesion? 4) Is there enhancement of the internal "matrix" of the lesion? 5) What is the relationship of the lesion to the carotid artery?

Brain Neoplasms↗
PubMed1995

Lesions of the parapharyngeal space. Role of MR imaging.

Because the parapharyngeal space is one of the deep spaces of the upper neck, it is a difficult region to examine clinically. On each side of the head, this space is located lateral to the pharynx and medial to the ramus of the mandible, the pterygoid muscles, and the parotid gland. It is only with bimanual palpation that any small fullness within this space may be clinically appreciated. When a parapharyngeal mass is sufficiently large, it displaces the lateral pharyngeal wall and pharyngeal tonsil toward the midline and may cause lateral displacement of the parotid gland. Only when a lesion is very large does it manifest as a fullness near the angle of the mandible. Thus, clinical evaluation of the space is quite limited.

Humans↗
PubMed1994

Advances in treatment of tumors of the cranial base. Advances in imaging.

Imaging has facilitated aggressive skull base surgery by allowing precise preoperative delineation of the extent of lesions. Continued advances providing even better resolution on imaging studies may in turn facilitate the development of new surgical approaches to the skull base.

Adipose Tissue↗