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Serial Magnetic Resonance Imaging (serial + magnetic_resonance_imaging)
Selected AbstractsReducing morphological variability of the cervical carotid artery in serial magnetic resonance imaging using a head and neck immobilization deviceJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2008Brian E. Chapman PhD Abstract Purpose To evaluate how well a head and neck immobilization device performed in reducing lumen morphology variability in repeated MR imaging of the carotid artery. Materials and Methods Quantitative measures of lumen and plaque characteristics may be important for longitudinal management of carotid atherosclerotic disease. However, quantitative measurements of the carotid artery are limited by their dependence on patient positioning, which can be quite variable. We created a head and neck immobilization device to reduce the variability of patient positioning during MR imaging of the carotid artery. In this article we describe the design and use of the immobilization device and assess how well its use reduced variability in vascular orientation and measurements of the carotid lumen cross-sectional area. Evaluation was based on 15 subjects who were repeatedly imaged without the immobilization device and 14 subjects who were repeatedly imaged with the device. Results Use of the immobilization device decreased the orientation variability from 9.1° to 5.3° (P = 0.0006) and the variability (defined as the standard deviation divided by the mean) of the cross-sectional area decreased from 0.24 to 0.18 (P = 0.04). Conclusion Using the immobilization device effectively reduces variability in repeated imaging of the carotid arteries. J. Magn. Reson. Imaging 2008;28:258,262. © 2008 Wiley-Liss, Inc. [source] Methodological considerations for measuring rates of brain atrophyJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2003Jeffrey L. Gunter PhD Abstract Purpose To systematically compare two techniques for measuring brain atrophy rates from serial magnetic resonance imaging (MRI) studies. Materials and Methods Using the separation in atrophy rate between cohorts of cognitively normal elderly subjects and patients with Alzheimer's disease (AD) as the gold standard, we evaluated 1) different methods of computing volume change; 2) different methods for steps in image preprocessing,intensity normalization, alignment mask used, and bias field correction; 3) the effect of MRI acquisition hardware changes; and 4) the sensitivity of the method to variations in initial manual volume editing. For each of the preceding evaluations, measurements of whole-brain and ventricular atrophy rates were calculated. Results In general, greater separation between the clinical groups was seen with ventricular rather than whole-brain measures. Surprisingly, neither the use of bias field correction nor a major hardware change between the scan pairs affected group separation. Conclusion Atrophy rate measurements from serial MRI are candidates for use as surrogate markers of disease progression in AD and other dementing neurodegenerative disorders. The final method has excellent precision and accurately captures the expected biology of AD,arguably the two most important features if this technique is to be used as a biomarker of disease progression. J. Magn. Reson. Imaging 2003;18:16,24. © 2003 Wiley-Liss, Inc. [source] Brain atrophy rates in Parkinson's disease with and without dementia using serial magnetic resonance imagingMOVEMENT DISORDERS, Issue 12 2005Emma J. Burton PhD Abstract Increased rates of brain atrophy are seen in Alzheimer's disease, but whether rates are similarly increased in other dementias such as Parkinson's disease dementia (PDD) has not been well examined. We determined the rates of brain atrophy using serial magnetic resonance imaging (MRI) in PDD and compared this finding to rates seen in cognitively intact Parkinson's disease (PD) patients and age-matched control subjects. Thirty-one patients (PD = 18, PDD = 13) and 24 age-matched controls underwent serial volumetric 1.5 T MRI scans, approximately 1 year apart. Baseline and repeat scans were registered and quantification of the brain boundary shift integral was used to determine whole-brain atrophy rates. Rates of brain atrophy were significantly increased in PDD (1.12 ± 0.98%/year) compared to PD (0.31 ± 0.69%/year; P = 0.018) and control subjects (0.34 ± 0.76%/year; P = 0.015). There were no differences in atrophy rates between controls and PD (P = 0.79). No correlations between increased atrophy rates and age or dementia severity (Mini-Mental State Examination score) were observed. Serial MRI may be a useful tool for monitoring disease progression in PDD and further studies should investigate its utility for early diagnosis. © 2005 Movement Disorder Society [source] Retropharyngeal Lipoma Causing Obstructive Sleep Apnea: Case Report Including Five-Year Follow-Up,THE LARYNGOSCOPE, Issue 9 2002Neil G. Hockstein MD Abstract Objectives/Hypothesis Lipomas of the retropharyngeal space are rare and do not cause symptoms until they reach a large size. Although retropharyngeal lipoma is an uncommon entity, several reports of it appear in the literature, and the treatment has routinely been surgical excision. Such fatty tumors also carry the rare possibility of being liposarcomas, which further warrants their excision. We present the case of a lipoma of the retropharyngeal space extending from the nasopharynx to the superior mediastinum causing symptoms of obstructive sleep apnea. The patient had multiple medical problems and was on a regimen of anticoagulation therapy; therefore, he opted against surgical treatment. He has used continuous positive airway pressure and has been followed clinically and radiographically for 5 years. Radiographic follow-up of a retropharyngeal lipoma after a needle biopsy confirming its benign nature is a legitimate means of management of this rare condition. Study Design Case report of a 64-year-old man presenting with this rare lesion. Methods Computed tomography-guided needle biopsy of the mass was performed to obtain tissue diagnosis. Thereafter, the patient has been followed for 5 years with annual magnetic resonance imaging scans to determine growth or changes of the retropharyngeal mass. Results Fine-needle aspiration of the mass revealed mature adipose tissue intermixed with fibroconnective tissue, consistent with lipoma. Based on this result, we opted to follow this patient with serial magnetic resonance imaging scans, which have shown no change in size. There has also been no change in the patient's symptoms. Conclusions Large lipomas warrant excision, especially when their location produces pressure symptoms. However, when surgical morbidity is high, fine-needle aspiration biopsy and serial magnetic resonance imaging scans are a safe alternative. [source] | ||||||||||