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D M Yousem

Publications and source records attributed to D M Yousem.

At least 55 records · Page 3Linked to original sources
PubMed1997

Computed tomography in lacrimal outflow obstruction.

BACKGROUND: Acquired nasolacrimal duct obstruction is a common ophthalmologic problem. Despite widespread understanding of treatments available for nasolacrimal duct obstruction, few authors have commented on its etiology. Because the nasolacrimal system is anatomically related to important nasal and sinus structures, the authors postulated that acquired nasolacrimal duct obstruction and its complications might occur simultaneous to, and possibly as a consequence of, rhinologic or sinus disease. MATERIALS AND METHODS: Twenty-three patients with acquired nasolacrimal duct obstruction and 100 control patients were evaluated by coronal computed tomography for evidence of sinus disease or nasal abnormalities. Specifically, five findings were noted: ostiomeatal complex disease, ethmoidal opacification, agger nasi cell opacification, concha bullosa, and nasal septal deviation. RESULTS: Overall, 20 (87%) patients with acquired nasolacrimal duct obstruction demonstrated one or more radiologic finding of sinus disease or rhinologic abnormality whereas 63 (63%) control subjects exhibited these findings. This difference was determined to be statistically significant (P < 0.05). A statistically significant higher incidence of ethmoidal opacification, agger nasi cell opacification, and nasal septal deviation was observed in patients with nasolacrimal outflow obstruction than in controls. Differences in the incidence of ostiomeatal complex disease and concha bullosa were not found to be statistically significant. CONCLUSION: These data demonstrate a correlation between computed tomography findings of sinus disease or nasal abnormality and the presence of acquired nasolacrimal outflow obstruction. This association between radiologic evidence of sinorhinologic disorders and lacrimal outflow obstruction may imply that dacryocystitis, like sinus disease, may be produced by disease of the lateral nasal wall. When evaluating a patient with acquired nasolacrimal duct obstruction, the physician should consider evaluation for concomitant nasal and sinus disease.

Humans↗
PubMed1997

Reproducibility and reliability of volumetric measurements of olfactory eloquent structures.

RATIONALE AND OBJECTIVES: The authors assessed the reliability and reproducibility of volumetric measurements of olfactory bulbs and tracts (OBTs) and temporal lobes (TLs) with magnetic resonance (MR) imaging. METHODS: Repetitive MR imaging of two phantoms and OBTs and TLs of patients was performed. Regions of interest were manually drawn around the relevant structures, and their volumes were measured at workstations. Intra- and interobserver variability for the two readers were measured. Intraclass and Pearson correlation coefficients and mean percentage differences were calculated. RESULTS: The measured phantom volumes were within 1.9%-12% of the true volumes with a variability of < or = 5%. Intraclass and Pearson correlation coefficients were > or = 0.919 for measurements by a single reader and > or = 0.924 for measurements by different readers. The inter- and intraobserver variabilities were < or = 4.2% for TL and 11.3%-14.6% for OBTs. CONCLUSION: Volumetric measurements of the olfactory apparatus can be reliably and accurately reproduced from MR images.

Humans↗
PubMed1997

Functional MR imaging during odor stimulation: preliminary data.

PURPOSE: To determine the locations and extent of activation in areas of the brain at functional magnetic resonance (MR) imaging with olfactory stimulation and to determine whether accommodation or amplification of brain activation occurs with sequential olfactory stimulation. MATERIALS AND METHODS: Five adult men with normal senses of smell underwent multisection, gradient-echo, echo-planar imaging according to a blood-oxygen-level-dependent experimental paradigm. Odorants that nearly exclusively stimulate the olfactory system and odorants that stimulate the olfactory and trigeminal nerves were compared by using repetitive imaging procedures. RESULTS: Activation with olfactory nerve-mediated odorants was demonstrated in the orbitofrontal cortex (Brodmann area 11) with a right-sided predominance. Mild cerebellar stimulation was also observed. With repeated testing, overall activation with olfactory nerve-mediated odorants declined. Odorants that also stimulated the trigeminal nerve produced additional cingulate, temporal, cerebellar, and occipital activation. Activation with combined trigeminal and olfactory system odors increased more than sixfold with repeated testing. CONCLUSION: Olfactory nerve-mediated and combined olfactory and trigeminal nerve-mediated odorants activate different regions of the brain. Orbitofrontal stimulation spreads to all parts of the brain when a trigeminal component is added. Habituation (deactivation) occurs with repeated testing of olfactory nerve-mediated odorants, while, paradoxically, activation increases with repeated exposure to odors that also stimulate the trigeminal nerve.

Adult↗
PubMed1997

Synovial sarcomas of the head and neck: MR findings.

OBJECTIVE: MR images of six synovial sarcomas of the head and neck were evaluated to determine their characteristic sites of origin, size, extent, intensity, and contrast enhancement. It was hoped that specific MR characteristics could be defined to suggest this entity. CONCLUSION: A nonmucosal head and neck mass that is isointense to gray matter on T1-weighted images and is well defined yet heterogeneous, with septations, hemorrhage, cysts, calcification, or multilocularity, should raise suspicion of a synovial sarcoma. Because the appearance of synovial sarcomas varies and other masses may appear similar, no specific imaging characteristics define the entity.

Adult↗
PubMed1997

Can radiologists accurately predict preepiglottic space invasion with MR imaging?

OBJECTIVE: The purpose of this study was to evaluate whether observers of MR imaging can accurately predict invasion of the preepiglottic fat (PEF) in patients with oropharyngeal and supraglottic laryngeal squamous cell carcinoma. MATERIALS AND METHODS: For 41 patients with pathologically proven squamous cell carcinoma of the oropharynx and supraglottic larynx, we retrospectively analyzed their MR images for the presence or absence of PEF neoplastic invasion. Unenhanced T1-weighted, fat-suppressed T2-weighted, and contrast-enhanced fat-suppressed T1-weighted scans were analyzed independently by two neuroradiologists who were unaware of the surgical findings. Proof of diagnosis was determined by pathologic analysis, intraoperative assessment, or both. RESULTS: Sixteen patients had neoplastic infiltration of the PEF. All infiltration was correctly predicted by the two observers of MR imaging, resulting in a sensitivity of 100%. Twenty-five patients had no invasion of the PEF by pathologic or surgical evaluation or both. Of these patients, negative findings were correctly predicted on MR imaging in 21 patients, whereas positive findings were incorrectly predicted on MR imaging in the remaining four patients, resulting in a specificity of 84% and an accuracy of 90%. In two of the four false-positive cases, effacement of the fat in the preepiglottic space by large tumors was mistaken for invasion. In a third patient, spread to the paraglottic space was mistaken for PEF extension. In the fourth false-positive case, glandular tissue along the ventral epiglottis may have been mistaken for tumor. The observers believed that unenhanced sagittal and axial T1-weighted scans were particularly useful because fat saturation artifacts may degrade T2-weighted and contrast-enhanced T1-weighted scans. CONCLUSION: Unenhanced T1-weighted MR images are highly sensitive for neoplastic infiltration of the preepiglottic space in patients with oropharyngeal and supraglottic laryngeal carcinoma who are at risk for such spread. Identification of PEF invasion is important because it affects prognosis and may affect surgical management.

Adipose Tissue↗
PubMed1997

Heterotopic brain in the pterygopalatine fossa.

Heterotopic brain outside the cranial vault is uncommon. It occurs most frequently in the nasal region, although rests elsewhere in the aerodigestive tract have been reported. We describe a case of heterotopic brain in the pterygopalatine fossa.

Biopsy↗
PubMed1997

Adenoidal width and HIV factors.

PURPOSE: To determine the factors that correspond to adenoidal hypertrophy, often prominent in human immunodeficiency virus (HIV)-positive patients. METHODS: The sagittal T1-weighted MR images of 21 HIV-positive patients (age range, 25 to 50 years; mean, 37 years) and 21 healthy control subjects (age range, 24 to 55 years; mean, 35 years) were reviewed blindly and independently by two radiologists who measured the maximal dimension of the nasopharyngeal lymphoid tissue. Twenty-six additional HIV-positive patients were combined with the original 21 HIV-positive patients, and the hematologic studies of these 47 patients were compared with the adenoidal measurements to assess whether a relationship existed between nasopharyngeal prominence and hematocrit, white blood cell count, and CD4 count. RESULTS: Mean adenoidal width was 6.76 mm (SD, 5.82) in the HIV-positive population, but was only 3.36 mm (SD, 2.48) in the age-matched control group. Age and HIV status correlated with nasopharyngeal width measurements. No relationship between adenoidal width and hematocrit, CD4 count, or white blood cell count was evident. CONCLUSION: After correcting for age, we found that adenoidal lymphoid tissue is more abundant in HIV-positive persons than in control subjects. The hematologic ramifications of this finding remain uncertain.

Adenoids↗
PubMed1996

Primary malignant melanoma of the sinonasal cavity: MR imaging evaluation.

To evaluate the magnetic resonance (MR) imaging characteristics of primary malignant melanoma of the sinonasal cavity, T1- and T2-weighted MR images of 12 patients with primary sinonasal melanoma were retrospectively reviewed. Gadolinium-enhanced imaging was performed in seven cases. The MR images were compared with histopathologic results. There were seven melanotic melanomas and five amelanotic melanomas; hemorrhage was present in three melanotic and two amelanotic melanomas. The seven melanotic melanomas were hyperintense to gray matter on T1-weighted images (whether hemorrhage was present or not), consistent with the paramagnetic effect of melanin. Four of the five amelanotic melanomas had intermediate signal intensity on T1-weighted images; one was not detected. On T2-weighted images, all of the melanomas detected had intermediate though variable signal intensity compared with that of gray matter. On gadolinium-enhanced images, all cases demonstrated mild to moderate enhancement. The signal intensity of sinonasal melanoma appears to vary according to the histopathologic components of the tumor. High signal intensity within the lesion on T1-weighted images suggests the presence of melanin.

Aged↗
PubMed1996

MR evaluation of patients with congenital hyposmia or anosmia.

OBJECTIVE: The purpose of this study was to evaluate patients with reduced or no sense of smell since birth for sites of abnormality by MR imaging. MATERIALS AND METHODS: Twenty-five patients who reported no olfactory function since birth were evaluated by olfactory testing, sinonasal endoscopy, and MR imaging. Surface coil and head coil images of the olfactory bulbs, olfactory tracts, subfrontal cortex, and temporal lobes in contiguous 3-mm sections were obtained. Two reviewers determined unilateral olfactory bulb and tract volumes and temporal lobe volumes in two separate sessions. Qualitative grading for olfactory bulb, olfactory tract, olfactory sulcus, subfrontal region, hippocampus, and temporal lobe damage also was performed. RESULTS: The absence of olfactory bulbs and tracts (68-84%) or the presence of hypoplasia (16-32%) was noted in all cases. Eight individuals had Kallmann's syndrome (hypogonadotropic hypogonadism with anosmia). Temporal and/or frontal lobe volume loss was noted in five individuals and was mild in all but one individual. CONCLUSION: Congenital anosmia or hyposmia appears to be an olfactory bulb-olfactory tract phenomenon rather than a cerebral process.

Adult↗
PubMed1996

Parathyroid and thyroid imaging.

Whether to perform preoperative imaging for parathyroid adenomas is controversial in the "virgin neck" because surgery without imaging is successful in more than 90% of cases. To detect ectopic adenomas or unresected adenomas after failure of initial surgery often requires both a functional study, such as technetium-99m sestamibi nuclear scintigram, and a morphologic study, such as ultrasonography, computed tomography, or magnetic resonance imaging for anatomic landmarks. Most dominant thyroid masses require fine-needle aspiration for diagnosis. Nuclear scintigraphy is useful when the lesion is warm or hot, making a malignancy less likely, but cold lesions are nonspecific. Unless a mass is shown to infiltrate the surrounding soft tissue or spread to lymph nodes, the findings on most cross-sectional imaging studies are also nonspecific.

Humans↗
PubMed1996

The role of computed tomography and magnetic resonance imaging in planning for conservation laryngeal surgery.

Refined laryngeal conservation surgeries have been devised to maintain the voice while eradicating even extensive glottic and hypopharyngeal tumors. The role of diagnostic imaging is to adequately define the extent of disease in conjunction with endoscopy. Critical areas to be evaluated are the tongue base, vallecula, pre-epiglottic space, arytenoid cartilages, postcricoid region, hypopharynx, thyroid cartilage, and subglottis.

Humans↗
PubMed1996

Granular cell myoblastoma of the cervical esophagus: MR findings.

Granular cell myoblastomas are uncommon, typically benign tumors. Involvement of the esophagus is rare, and frequently they are asymptomatic. We report a granular cell myoblastoma involving the cervical esophagus in a patient who had paralysis of the true vocal cord and progressive dysphagia. At MR imaging, the circumscribed mass was hypointense on T1-weighted images and mildly hyperintense on T2-weighted images, with homogeneous contrast enhancement.

Adult↗
PubMed1995

Computed tomography-guided aspirations of parapharyngeal and skull base masses.

Computed tomography (CT)-guided aspirations of 22 parapharyngeal and skull base masses were performed via an oblique approach between the ascending ramus of the mandible and the pterygoid plates. A 22 g spinal needle was inserted through an 18 g introducer needle for sampling. Diagnostic specimens were obtained in 20 cases including six salivary gland neoplasms, five squamous cell carcinomas, five infections, and two cysts. On average, 2.8 passes into the mass were required although fewer were necessary to diagnose neoplasms (2.0 passes). No complications occurred. In this series, 100% of neoplasms were detected cytologically and there were no false-negative results. In two cases (9.1%) there was a discrepancy between the initial aspiration report and the final histologic diagnosis. CT-guided aspirations of skull base masses are a viable alternative to what would otherwise be a difficult surgical approach for biopsy. Diagnostic samples are obtained in 90.9% (20 of 22) with an accuracy of 90% (18 of 20).

Journal Article↗
PubMed1995

Carotid artery invasion by head and neck masses: prediction with MR imaging.

PURPOSE: To determine the value of magnetic resonance (MR) imaging in predicting resectability of head and neck neoplasms around the carotid arteries. MATERIALS AND METHODS: Forty-nine patients (28 male patients and 21 female patients aged 17-79 years; mean, 57.3 years) with head and neck masses and clinical evidence of carotid wall invasion underwent MR imaging. T1-weighted, T2-weighted, and gadolinium-enhanced T1-weighted images were analyzed to determine circumferential involvement of 53 arteries by tumor. RESULTS: More than 270 degrees of circumferential involvement was considered suggestive of unresectability of the malignant neoplasm; 270 degrees or less was considered lack of invasion. The sensitivity of MR imaging for determination of unresectable disease was 100% (12 of 12 cases), specificity was 88% (36 of 41), and accuracy was 91% (48 of 53). Accuracy was 100% for squamous cell carcinoma (n = 29). CONCLUSION: Tumor that encompasses more than 270 degrees of the carotid artery probably cannot be removed from the artery. Tumor that involves 270 degrees or less of the artery can be removed.

Adolescent↗
PubMed1995

MR evaluation of frontal sinus osteoplastic flaps with autogenous fat grafts.

PURPOSE: To investigate the MR findings in patients who have had osteoplastic frontal sinus flaps placed for inflammatory sinonasal disease. METHODS: The MR images of 13 patients who had improvement of symptoms after osteoplastic frontal sinus flap placement with fat autograft were prospectively evaluated for the presence of high intensity on T2-weighted scans, contrast enhancement, and replacement of frontal sinus fat by lower-signal soft tissue. All studies were performed on a 1.5-T unit using a 5-in round surface coil placed over the nasion. Sagittal T1-weighted, axial and coronal fast spin-echo T2-weighted, and precontrast and postcontrast axial and coronal T1-weighted images were obtained through the operative bed. The T2-weighted and postgadolinium sequences were done with a fat-suppression technique. RESULTS: Hyperintensity within the frontal sinuses on T2-weighted images and enhancement (peripherally and/or centrally where fat was replaced with soft tissue) were found to some degree in all patients. The degree of replacement of frontal sinus fat with soft tissue ranged from 4% to 85% (mean, 43%). Five patients with persistent symptoms had no distinguishing MR features when compared with asymptomatic patients. CONCLUSIONS: Although increased T2-weighted intensity, fat replacement, and enhancement are findings compatible with inflammation, these changes may be seen in patients who are asymptomatic after placement of osteoplastic frontal sinus flaps; they may represent the normal granulation process. MR findings after flap placement are nonspecific and have limited utility in distinguishing symptomatic patients with recurrent inflammatory disease from asymptomatic patients whose imaging findings are related to postoperative scar tissue.

Adipose Tissue↗