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Biomedical subjects

J A Castelijns

Publications and source records attributed to J A Castelijns.

82 records · Page 5Linked to original sources
PubMed1988

Invasion of laryngeal cartilage by cancer: comparison of CT and MR imaging.

Forty-two patients with laryngeal carcinomas were examined with computed tomography (CT) and magnetic resonance (MR) imaging. The accuracy of both CT and MR imaging in the depiction of cartilage invasion was evaluated in 16 patients by comparing findings at CT and MR with pathologic findings. Calcified cartilage that has been invaded by cancer is frequently seen on CT scans as having an intact contour. Tumor approaching nonossified cartilage may simulate cartilage invasion. On T1-weighted MR images, invaded marrow of ossified cartilage is of intermediate signal intensity, allowing it to be differentiated from normal bone marrow. On proton-density images, tumor is of increased signal intensity, which allows it to be differentiated from nonossified cartilage. In our experience, the specificities of CT and MR imaging were approximately equal (91% and 88%, respectively), but CT had a considerably lower sensitivity than MR (46% vs. 89%). Gross movement artifacts, which resulted in nondiagnostic images, occurred in 16% of the MR examinations. MR imaging is recommended as the modality of choice in the diagnosis of cartilage invasion.

Aged↗
PubMed1987

MRI of normal or cancerous laryngeal cartilages: histopathologic correlation.

MRI appearances of laryngeal cartilages, normal or invaded by cancer, are still relatively unfamiliar to most clinicians. Twelve primary laryngeal tumors out of a series of 65 patients which have been investigated by MRI were examined postoperatively by macroscopic and microscopic sectioning of the surgical specimens. Images were obtained with a 0.6 Tesla superconductive system using a solenoid surface coil. The authors emphasize the value of a combined use of T1-weighted and balanced (relatively T2-weighted images with still T1-characteristics) Spin Echo images. T1-weighted images permit differentiation between pathological and normal bone marrow. Balanced images allow separation between nonossified cartilage and tumor tissue. MRI is an additional tool in the diagnostic workup of cartilage invasion by tumor.

Aged↗
PubMedDate not supplied

MR imaging of the normal larynx.

Magnetic resonance imaging of the larynx was performed on 15 volunteers. Searching for optimal images in the sagittal, frontal, and transverse planes, we compared images made with a special surface coil and the standard head coil, images with different slice thicknesses, images with different repetition times (TR) and images with different matrices. The field of view and the scan times were kept as small as possible. Using a surface coil, we obtained high resolution images in all three planes. These images provide clinically relevant information, not shown by current radiological techniques: hyoepiglottic ligament, thyrohyoid ligament, thyroepiglottic ligament and cricothyroid ligament, the borders between the preepiglottic space and both paraglottic spaces (PGS), the borders between both PGS and thyroid cartilage, and the vocalis and thyroarytenoid muscles. Short TR is preferred because, with shorter scan time, more measurements could be made. Images with a 128 X 128 matrix size had a much better signal-to-noise ratio than images with a 256 X 256 matrix size. Magnetic resonance has great potential in imaging normal and pathological anatomy of the larynx.

Adult↗
PubMedDate not supplied

MR imaging of laryngeal cancer.

Forty-four consecutive patients with laryngeal carcinomas presenting at different stages of the disease were investigated by magnetic resonance (MR) imaging. Twelve patients (six with primary lesions and six with recurrent tumors) underwent laryngectomy, and the macro- and microscopic appearance of the slice specimens were correlated with MR imaging. In the remaining patients surgery was not performed, and MR results are compared with the laryngoscopic findings. Cancerous tissue was seen on T1-weighted images as a homogeneous mass of intermediate signal intensity. slightly higher than infrahyoid muscles. The MR examinations failed mainly in patients with tumor recurrence who had undergone previous radiation treatment.

Aged↗
PubMedDate not supplied

Detection and characterization of metastatic cervical adenopathy by MR imaging: comparison of different MR techniques.

Thirty-five patients scheduled to undergo a neck dissection for squamous cell carcinoma of the head and neck were evaluated preoperatively by magnetic resonance (MR) imaging. Axial and occasionally sagittal and coronal images were obtained. To define the most reliable technique to detect cervical lymph node metastasis, we compared several MR pulse sequences with and without Gd-DTPA administration to histopathologic findings in the neck dissection specimens. T1-weighted spin echo combined with T2-weighted gradient recalled echo (GE) sequences were found to be more useful than any other combination of pulse sequences in localizing lymph nodes. On T2-weighted GE images, lymph nodes were depicted with intermediate to high signal intensity in contrast to low signal muscular and fatty tissue. Gadolinium DTPA enhanced T1-weighted GE images reliably depict central lymph node necrosis, the most specific criterion for lymph node metastasis.

Adult↗
PubMedDate not supplied

Perineural tumor extension of facial malignant melanoma: CT and MRI.

A case of retrograde perineural tumor that spread from malignant melanoma of the face is reported. Contrast-enhanced CT and plain and contrast-enhanced MR studies, including fat suppression technique, showed tumor extension along the maxillary division of the trigeminal nerve. Histopathological examination of the surgical specimen revealed neurotropic malignant melanoma and confirmed the extent of tumor spread in the perineurium.

Aged↗
PubMedDate not supplied

Correlation between electromyographic reflex and MR imaging examinations of the trigeminal nerve.

BACKGROUND AND PURPOSE: Previous studies have shown that clinical localization of trigeminal nerve lesions is inaccurate as compared with MR imaging findings. The purpose of our study was to ascertain the added value of electromyographic (EMG) investigation of the trigeminal nerve reflexes for the improvement of lesion localization and for the preselection of patients for MR imaging. METHODS: We reviewed the EMG studies of the trigeminal reflexes and the MR imaging studies of 20 patients with unilateral symptoms and signs related to the trigeminal nerve (40 trigeminal nerves examined). The results of the two studies were compared to assess the value of EMG in predicting MR imaging outcome. Lesion localization as demonstrated by EMG was compared with localization at MR imaging. MR imaging was used as the standard of reference. RESULTS: Eight (40%) of 20 patients had MR imaging findings related to presenting trigeminal symptoms, including five brain stem lesions and three peripheral lesions. Fourteen (70%) of 20 patients had EMG abnormalities related to presenting symptoms and signs. For brain stem lesions, lesion localization as shown by EMG corresponded well with MR imaging findings. EMG yielded a sensitivity of 100%, a specificity of 81%, a positive predictive value of 57%, and a negative predictive value of 100% in predicting MR imaging results. Interobserver agreement was good for both the EMG reflex and MR imaging examinations. CONCLUSION: Our data suggest that EMG recordings of the trigeminal reflexes can be used to exclude structural lesions in patients with symptoms related to the trigeminal nerve. When a lesion is localized in the brain stem with EMG, a tailored MR imaging examination of this region may be sufficient.

Adult↗
PubMedDate not supplied

MR of the spinal cord in multiple sclerosis: relation to clinical subtype and disability.

PURPOSE: To determine whether the MR appearance of the spinal cord in patients with multiple sclerosis (MS) differs according to clinical subtype. METHODS: The spinal cords of 20 healthy control subjects and 60 patients with MS (22 with relapsing-remitting disease, 22 with secondary-progressive disease, and 16 with primary-progressive disease) were examined with sagittal dual-echo spin-echo MR imaging and with axial T2*-weighted gradient-echo MR imaging. Two interpreters scored the images for focal lesions and for diffuse abnormalities. Cross-sectional areas of the cords were measured at the C-2 level. RESULTS: No abnormalities were found in any of the control subjects nor in two of the patients. Fifty (83%) of 60 patients had focal lesions. Diffuse abnormality and focal lesions were found in 50% of patients with secondary-progressive MS, in 25% of patients with primary-progressive disease, and in 18% of patients with relapsing-remitting disease. Diffuse abnormality without focal lesions was found in seven patients with primary-progressive MS and in one patient with secondary-progressive MS. Patients with diffuse abnormalities had a smaller cross-sectional area of the spinal cord and they suffered from more disability than did patients without diffuse abnormalities. CONCLUSION: The MR appearance of the spinal cord differs among clinical subgroups of MS. Diffuse abnormality of the spinal cord is associated with a progressive clinical course and greater disability.

Activities of Daily Living↗
PubMedDate not supplied

MR outcome parameters in multiple sclerosis: comparison of surface-based thresholding segmentation and magnetization transfer ratio histographic analysis in relation to disability (a preliminary note).

BACKGROUND AND PURPOSES: MR imaging is now widely used to monitor disease progression in patients with multiple sclerosis (MS). The purpose of this study was to explore the relationship between disability status and existing and new MR parameters in MS patients. METHODS: Forty-one patients with clinically definitive MS were studied. MR imaging included T2- and T1-weighted imaging as well as gradient-echo imaging with and without magnetization transfer contrast. We used surface-based thresholding segmentation techniques to obtain T2 and T1 lesion load, T1/T2 ratio, and several magnetization transfer ratio (MTR) lesion load parameters. MTR histographic analysis included measurements of absolute peak height (aHp), relative peak height (rHp), MTR of the peak (MTRp), mean MTR (MTRm), and MTR25, MTR50, and MTR75, relating to the integrals of the histogram at 25%, 50%, and 75%, respectively, of the total area under the curve. All MR parameters were correlated with Expanded Disability Status Scale (EDSS) score, disease duration, and patient's age. RESULTS: Using surface-based thresholding segmentation techniques, we found relatively low correlations with EDSS. T1 lesion load and T1/T2 ratios correlated most strongly. Regarding MTR histographic parameters, EDSS correlated best with rHp but only weakly with others. Similar correlations were found with disease duration, but not with age. CONCLUSION: The best MR correlations with disability were several MTR histographic parameters. Our findings may favor the use of these MR parameters over T2 lesion load to monitor disease progression in patients with MS, findings that should be explored further in longitudinal studies.

Adolescent↗