Critical Assessment of Myelography Practices: A Call for Rational Guideline Revision.

BACKGROUND AND PURPOSE: Patient preparation for myelography and postprocedural monitoring varies widely between practices, despite published guidelines. Our aim was to examine the current practice variations in discontinuing reportedly seizure threshold-lowering medications before myelography and to assess the reported incidence of postmyelographic seizures. MATERIALS AND METHODS: An e-mail survey was sent to American Society of Neuroradiology members concerning the number of postmyelographic seizures experienced in the past 5 years, the presence of an institutional policy for discontinuing seizure threshold-lowering medications, and the type of myelographic contrast used. We compared the postmyelographic seizure frequency in the responses. RESULTS: Of 700 survey responses, 57% reported that they do not discontinue seizure threshold-lowering medications before myelography. Most (97%) indicated never having a patient experience a seizure following myelography. The number of postmyelographic seizures between those who discontinue seizure threshold-lowering medications and those who do not was not statistically significant (OR = 2.13; 95% CI, 0.91-4.98; P = .08). Most (95%) reported using nonionic hypo-osmolar agents. CONCLUSIONS: Survey results revealed widely variable practices for patient myelography preparation and postprocedural monitoring. We found no difference in reported seizures between those who discontinued seizure threshold-lowering medications and those who did not. In light of our findings, we propose that discontinuing reportedly seizure threshold-lowering medications is not warranted with the current nonionic water-soluble contrast agents and may be potentially harmful in some instances. This work supports revision of existing recommendations to withhold such medications before myelography.

Optimal Fat Suppression in Head and Neck MRI: Comparison of Multipoint Dixon with 2 Different Fat-Suppression Techniques, Spectral Presaturation and Inversion Recovery, and STIR.

BACKGROUND AND PURPOSE: Uniform complete fat suppression is essential for identification and characterization of most head and pathology. Our aim was to compare the multipoint Dixon turbo spin-echo fat-suppression technique with 2 different fat-suppression techniques, including a hybrid spectral presaturation with inversion recovery technique and an inversion recovery STIR technique, in head and neck fat-suppression MR imaging. MATERIALS AND METHODS: Head and neck MR imaging datasets of 72 consecutive patients were retrospectively reviewed. All patients were divided into 2 groups based on the type of fat-suppression techniques used (group A: STIR and spectral presaturation with inversion recovery gadolinium-T1WI; group B: multipoint Dixon T2 TSE and multipoint Dixon gadolinium-T1WI TSE). Objective and subjective image quality and scan acquisition times were assessed and compared between multipoint Dixon T2 TSE versus STIR and multipoint Dixon gadolinium-T1WI TSE versus spectral presaturation with inversion recovery gadolinium-T1WI using the Mann-Whitney U test. RESULTS: A total of 64 patients were enrolled in the study (group A, n = 33 and group B, n = 31). Signal intensity ratios were significantly higher for multipoint Dixon T2 and gadolinium-T1WI techniques compared with STIR (P < .001) and spectral presaturation with inversion recovery gadolinium-T1WI (P < .001), respectively. Two independent blinded readers revealed that multipoint Dixon T2 and gadolinium-T1WI techniques had significantly higher overall image quality (P = .022 and P < .001) and fat-suppression grades (P < .013 and P < .001 across 3 different regions) than STIR and spectral presaturation with inversion recovery gadolinium-T1WI, respectively. The scan acquisition time was relatively short for the multipoint Dixon technique (2 minutes versus 4 minutes 56 seconds for the T2-weighted sequence and 2 minutes versus 3 minutes for the gadolinium-T1WI sequence). CONCLUSIONS: The multipoint Dixon technique offers better image quality and uniform fat suppression at a shorter scan time compared with STIR and spectral presaturation with inversion recovery gadolinium-T1WI techniques.

MR Imaging of the Superior Cervical Ganglion and Inferior Ganglion of the Vagus Nerve: Structures That Can Mimic Pathologic Retropharyngeal Lymph Nodes.

BACKGROUND AND PURPOSE: The superior cervical ganglion and inferior ganglion of the vagus nerve can mimic pathologic retropharyngeal lymph nodes. We studied the cross-sectional anatomy of the superior cervical ganglion and inferior ganglion of the vagus nerve to evaluate how they can be differentiated from the retropharyngeal lymph nodes. MATERIALS AND METHODS: This retrospective study consists of 2 parts. Cohort 1 concerned the signal intensity of routine neck MR imaging with 2D sequences, apparent diffusion coefficient, and contrast enhancement of the superior cervical ganglion compared with lymph nodes with or without metastasis in 30 patients. Cohort 2 used 3D neurography to assess the morphology and spatial relationships of the superior cervical ganglion, inferior ganglion of the vagus nerve, and the retropharyngeal lymph nodes in 50 other patients. RESULTS: All superior cervical ganglions had homogeneously greater enhancement and lower signal on diffusion-weighted imaging than lymph nodes. Apparent diffusion coefficient values of the superior cervical ganglion (1.80 ± 0.28 × 10-3mm2/s) were significantly higher than normal and metastatic lymph nodes (0.86 ± 0.10 × 10-3mm2/s, P < .001, and 0.73 ± 0.10 × 10-3mm2/s, P < .001). Ten and 13 of 60 superior cervical ganglions were hypointense on T2-weighted images and had hyperintense spots on both T1- and T2-weighted images, respectively. The latter was considered fat tissue. The largest was the superior cervical ganglion, followed in order by the retropharyngeal lymph node and the inferior ganglion of the vagus nerve (P < .001 to P = .004). The highest at vertebral level was the retropharyngeal lymph nodes, followed, in order, by the inferior ganglion of the vagus nerve and the superior cervical ganglion (P < .001 to P = .001). The retropharyngeal lymph node, superior cervical ganglion, and inferior ganglion of the vagus nerve formed a line from anteromedial to posterolateral. CONCLUSIONS: The superior cervical ganglion and the inferior ganglion of the vagus nerve can be almost always differentiated from retropharyngeal lymph nodes on MR imaging by evaluating the signal, size, and position.

Intranasal Esthesioneuroblastoma: CT Patterns Aid in Preventing Routine Nasal Polypectomy.

BACKGROUND AND PURPOSE: Esthesioneuroblastoma is a neuroectodermal tumor that commonly arises in the nasal cavity olfactory recess and, when isolated to the intranasal cavity, can be indistinguishable from benign processes. Because lesional aggressiveness requires a more invasive operation for resection than polypectomy, patients with isolated intranasal lesions were studied to define distinguishing CT characteristics. MATERIALS AND METHODS: Patients with intranasal esthesioneuroblastoma and controls without esthesioneuroblastoma with olfactory recess involvement were identified by using a report search tool. Studies demonstrating skull base invasion and/or intracranial extension were excluded. The imaging spectrum of these lesions was reviewed on both CT and MR imaging, and CT findings were compared with those of controls without esthesioneuroblastoma. Two blinded readers assessed subjects with esthesioneuroblastomas and controls without esthesioneuroblastoma and, using only CT criteria, rated their level of suspicion for esthesioneuroblastoma in each case. RESULTS: Eight histologically proved cases of intranasal esthesioneuroblastoma were reviewed. All cases had CT demonstrating 3 main findings: 1) an intranasal polypoid lesion with its epicenter in a unilateral olfactory recess, 2) causing asymmetric olfactory recess widening, and 3) extending to the cribriform plate. Twelve patients with non-esthesioneuroblastoma diseases involving the olfactory recess were used as controls. Using these 3 esthesioneuroblastoma CT criteria, 2 blinded readers evaluating patients with esthesioneuroblastoma and controls had good diagnostic accuracy (area under the curve = 0.85 for reader one, 0.81 for reader 2) for predicting esthesioneuroblastoma. CONCLUSIONS: Esthesioneuroblastoma can present as a well-marginated intranasal lesion that unilaterally widens the olfactory recess. CT patterns can help predict esthesioneuroblastoma, potentially preventing multiple operations by instigating the correct initial operative management.

Do Radiologists Report the TNM Staging in Radiology Reports for Head and Neck Cancers? A National Survey Study.

BACKGROUND AND PURPOSE: CT and MR imaging are widely used for the staging of head and neck cancer. Currently, there are no data regarding whether the primary tumor, nodes, metastasis (TNM) staging is routinely incorporated into radiology reports. We conducted a national survey to determine whether radiologists routinely address staging, in particular regarding T (primary tumor) and N (nodal). MATERIALS AND METHODS: The survey was sent to 782 members of the American Society of Head and Neck Radiology. The survey asked whether they assign TN staging in reports. If they do assign TN staging, what are the reasons for doing so, and if not, what are the barriers or reasons for not including it in the radiology report? The method of measuring the size of the primary tumor and pathologic lymph nodes was also queried. RESULTS: A total of 229 responses were returned (29.3% response rate). Approximately half (49%; 95% confidence interval, 43.55-54.5%) of the responders thought that incorporating TN staging is important. However, only 24.5% (95% confidence interval, 19.8%-29.2%) stated that they routinely assigned TN staging in their radiology reports. The most common barriers were being afraid of being inaccurate (59%) and being unable to remember the staging classifications (58.2%); 76.9% indicated that they measure a primary tumor in 3D. CONCLUSIONS: Staging head and neck cancer based on imaging presents unique challenges. Nearly half of the responding radiologists think it is important to incorporate TN staging in radiology reports, though only a quarter of them routinely do so in practice.

Dynamic Contrast-Enhanced MR Imaging in Head and Neck Cancer: Techniques and Clinical Applications.

In the past decade, dynamic contrast-enhanced MR imaging has had an increasing role in assessing the microvascular characteristics of various tumors, including head and neck cancer. Dynamic contrast-enhanced MR imaging allows noninvasive assessment of permeability and blood flow, both important features of tumor hypoxia, which is a marker for treatment resistance for head and neck cancer. Dynamic contrast-enhanced MR imaging has the potential to identify early locoregional recurrence, differentiate metastatic lymph nodes from normal nodes, and predict tumor response to treatment and treatment monitoring in patients with head and neck cancer. Quantitative analysis is in its early stage and standardization and refinement of technique are essential. In this article, we review the techniques of dynamic contrast-enhanced MR imaging data acquisition, analytic methods, current limitations, and clinical applications in head and neck cancer.

Imaging evidence and recommendations for traumatic brain injury: advanced neuro- and neurovascular imaging techniques.

SUMMARY: Neuroimaging plays a critical role in the evaluation of patients with traumatic brain injury, with NCCT as the first-line of imaging for patients with traumatic brain injury and MR imaging being recommended in specific settings. Advanced neuroimaging techniques, including MR imaging DTI, blood oxygen level-dependent fMRI, MR spectroscopy, perfusion imaging, PET/SPECT, and magnetoencephalography, are of particular interest in identifying further injury in patients with traumatic brain injury when conventional NCCT and MR imaging findings are normal, as well as for prognostication in patients with persistent symptoms. These advanced neuroimaging techniques are currently under investigation in an attempt to optimize them and substantiate their clinical relevance in individual patients. However, the data currently available confine their use to the research arena for group comparisons, and there remains insufficient evidence at the time of this writing to conclude that these advanced techniques can be used for routine clinical use at the individual patient level. TBI imaging is a rapidly evolving field, and a number of the recommendations presented will be updated in the future to reflect the advances in medical knowledge.

Impact of model-based iterative reconstruction on image quality of contrast-enhanced neck CT.

BACKGROUND AND PURPOSE: Improved image quality is clinically desired for contrast-enhanced CT of the neck. We compared 30% adaptive statistical iterative reconstruction and model-based iterative reconstruction algorithms for the assessment of image quality of contrast-enhanced CT of the neck. MATERIALS AND METHODS: Neck contrast-enhanced CT data from 64 consecutive patients were reconstructed retrospectively by using 30% adaptive statistical iterative reconstruction and model-based iterative reconstruction. Objective image quality was assessed by comparing SNR, contrast-to-noise ratio, and background noise at levels 1 (mandible) and 2 (superior mediastinum). Two independent blinded readers subjectively graded the image quality on a scale of 1-5, (grade 5 = excellent image quality without artifacts and grade 1 = nondiagnostic image quality with significant artifacts). The percentage of agreement and disagreement between the 2 readers was assessed. RESULTS: Compared with 30% adaptive statistical iterative reconstruction, model-based iterative reconstruction significantly improved the SNR and contrast-to-noise ratio at levels 1 and 2. Model-based iterative reconstruction also decreased background noise at level 1 (P = .016), though there was no difference at level 2 (P = .61). Model-based iterative reconstruction was scored higher than 30% adaptive statistical iterative reconstruction by both reviewers at the nasopharynx (P < .001) and oropharynx (P < .001) and for overall image quality (P < .001) and was scored lower at the vocal cords (P < .001) and sternoclavicular junction (P < .001), due to artifacts related to thyroid shielding that were specific for model-based iterative reconstruction. CONCLUSIONS: Model-based iterative reconstruction offers improved subjective and objective image quality as evidenced by a higher SNR and contrast-to-noise ratio and lower background noise within the same dataset for contrast-enhanced neck CT. Model-based iterative reconstruction has the potential to reduce the radiation dose while maintaining the image quality, with a minor downside being prominent artifacts related to thyroid shield use on model-based iterative reconstruction.

Staging of laryngeal cancer using 64-channel multidetector row CT: comparison of standard neck CT with dedicated breath-maneuver laryngeal CT.

BACKGROUND AND PURPOSE: With a 64-channel multidetector row CT, imaging acquisition during speech, swallowing, or phonation has become feasible. However, the actual benefit of these additional focused images should be critically evaluated with respect to radiation dose. The purpose of this study was to determine if dedicated laryngeal CT using breath-holding and straw-blowing improved the accuracy of TNM-staging for patients with biopsy-proved laryngeal carcinomas in comparison with a standard neck CT. MATERIALS AND METHODS: A total of 27 patients underwent a standard neck CT and a laryngeal CT with additional images acquired while patients held their breath or blew through a straw. Two radiologists interpreted the neck CT and later the laryngeal CT and assigned a TNM-stage for each case. These interpretations were compared with a TNM-stage determined by surgery and/or clinical examination for the individual patients. The accuracy of standard neck CT was compared with the accuracy of laryngeal CT. RESULTS: The overall accuracy was not significantly different between standard neck CT and the additional laryngeal CT and was, in fact, lower in cases with additional larynx images. The accuracy of staging was slightly improved with the additional laryngeal CT for glottic cancers; however, it was decreased for supraglottic cancers. The accuracy of a dichotomous diagnosis of early-versus-advanced-stage cancer was 0.86 for the standard neck CT and 0.80 for the laryngeal CT. The readers' confidence levels did not improve with the use of the additional images. CONCLUSIONS: In the era of isovoxel multidetector CT technology and judicious monitoring of radiation dose, a standard neck CT with coronal and sagittal reformats should suffice for the staging of laryngeal cancer.

Balancing radiation dose and image quality: clinical applications of neck volume CT.

BACKGROUND AND PURPOSE: The advancement of multidetector CT technology has resulted in improved image quality as well as an increase in ionizing radiation dose to patient. The purpose of this study was to assess radiation dose and overall image quality of CT examination of the neck between fixed-tube current and automatic tube current modulation (ATCM) at 2 separate noise index levels. MATERIALS AND METHODS: A total of 84 patients underwent neck CT with use of a 64-section multidetector row CT (MDCT) scanner. Patients were divided into 3 groups: fixed-tube current (n = 28), ATCM with a noise index of 11.4 (n = 28), and ATCM with a noise index of 20.2 (n = 28). All other scan parameters remained constant. Scan coverage length and transclavicular distance were measured. Two radiologists blinded to the scanning parameters assessed overall image quality, noise level, and streak artifacts using a 5-point grading scale. The radiation dose in dose-length product (DLP) and CT dose index (CTDI) was recorded. RESULTS: Compared with a fixed-tube current technique, ATCM with a noise index of 11.4 reduced CTDI by 20% (P < .01 x 10(-6)), and ATCM with a noise index of 20.2 reduced CTDI by 34% (P < .01 x 10(-12)). Although the difference in image quality between the fixed-tube current technique and the noise index reached statistical significance (P < .05), the magnitude of the difference was small, with average scores of 3.79 (+/-0.59) and 3.57 (+/-0.53), respectively. CONCLUSION: Compared with the fixed-tube current technique, ATCM resulted in significant reduction of radiation dose without substantially reducing the image quality of the CT of the neck. Judicious monitoring of radiation dose to patients has to be balanced with diagnostic image quality.

In vivo manganese MR imaging of calcium influx in spontaneous rat pituitary adenoma.

BACKGROUND AND PURPOSE: Rapid uptake of the calcium analog manganese (Mn2+) into spontaneous pituitary adenoma during MR imaging of aged rats generated the hypothesis that neuroendocrine tumors may have a corresponding increase in calcium influx required to trigger hormonal release. A goal of this study was to investigate the potential for clinical evaluation of pituitary adenoma by MR imaging combined with administration of Mn2+ (Mn-MR imaging). MATERIALS AND METHODS: Mn-MR imaging was used to characterize the dynamic calcium influx in normal aged rat pituitary gland as well as spontaneous pituitary adenoma. To confirm the validity of Mn2+ as a calcium analog, we inhibited Mn2+ uptake into the olfactory bulb and pituitary gland of normal rats by using the calcium channel blocker verapamil. Rats with adenomas received fluorodeoxyglucose-positron-emission tomography (FDG-PET) scanning for characterization of tumor metabolism. Mn2+ influx was characterized in cultured pituitary adenoma cells. RESULTS: Volume of interest analysis of the normal aged pituitary gland versus adenoma indicated faster and increased calcium influx in adenoma at 1, 3, 11, and 48 hours. Mn2+ uptake into the olfactory bulb and pituitary gland of normal rats was inhibited by calcium channel blockers and showed dose-dependent inhibition on dynamic MR imaging. FDG-PET indicated correlation between tumor energy metabolism and Mn2+ influx as well as tumor size. CONCLUSION: These results indicate that adenomas have increased activity-dependent calcium influx compared with normal aged pituitary glands, suggesting a potential for exploitation in the clinical work-up of pituitary and other neuroendocrine tumors by developing Mn-MR imaging for humans.

Writing 40 nm marks by using a beaked metallic plate near-field optical probe.

We have developed a near-field optical probe that uses a triangular metallic plate with a three-dimensionally tapered apex as a light source for thermally assisted magnetic recording. Numerical analysis using a finite-element method shows that the size of the optical spot generated at the apex is 15 nm x 20 nm, and the efficiency (defined as the ratio between the power of the optical near field at the surface of the recording medium and that of the incident light) is 15% when the incident light is focused by a lens with a numerical aperture of 0.8. The metallic plate was fabricated on the surface of a quartz slider and used for writing marks on a phase change recording medium. The marks were observed with a scanning electron microscope, and we confirmed that marks with a diameter of 40 nm were successfully written on the medium.

Efficiency of transfection and localization of superparamagnetic iron oxide particles in neural progenitor cells using two methods.

Stem cells represent a potentially revolutionary therapy for neurological pathologies but for which a thorough investigation of cell behavior in the living nervous system has yet to be performed. Contrast-enhanced cell tracking with magnetic resonance imaging can enable this investigation by introducing superparagmagnetic iron oxide (SPIO) particles within the cell membrane. Before magnetically labeled cells can be observed in vivo, it is essential to maximize SPIO transfer into the cell and to fully understand the localization of the contrast agent in mature neural cells. For practical applications, a quantitative evaluation of labeled cells before implantation will allow in vivo assertions. In this study, we present a comparison between two methods for magnetic transfection of neural progenitor cells: the hemmaglutinating virus of Japan envelope (HVJ-E) as a viral vector and a liposomal reagent. We show that HVJ-E is a more efficient vehicle of cell transfection using quantitative evaluation and that the iron content per cell can be predicted using a simple, automated image analysis of stained, labeled cells. Image analysis is also used in this study to show that the contrast agent is distributed in the axon after differentiation, an important aspect of understanding cell tracking in vivo.

Medical care expenditure associated with body mass index in Japan: the Ohsaki Study.

OBJECTIVE: To examine the impact of body mass index (BMI) upon medical care use and its costs in Japan. DESIGN: A population-based prospective cohort study from 1995 to 1998. SUBJECTS: A cohort of 41 967 Japanese adults aged 40-79 y. Subjects who died during the first year of follow-up, or who at baseline reported having had cancer, myocardial infarction, stroke or kidney disease were excluded. MEASUREMENTS: Medical care use and its costs, actual charges, by linkage with the National Health Insurance claim history files after adjustment of smoking, drinking and physical functioning status. RESULTS: There was a U-shaped association between BMI and total medical costs. The nadir of the curve was found at a BMI of 21.0-22.9 kg/m(2). Relative to the nadir, total costs were 9.8% greater among those with BMIs of 25.0-29.9 (rate ratio, 1.10; 95% confidence interval (CI), 1.03-1.17), and 22.3% greater among those with BMIs of 30.0 or higher (rate ratio, 1.22; 95% CI, 1.08-1.37). Estimated excess direct costs attributable to overweight (BMI of 25.0-29.9 kg/m(2)) and obesity (BMI of 30.0 kg/m(2) or higher) represent 3.2% of total health expenditure in the present study, which is within the range reported in Western countries (0.7-6.8%). CONCLUSION: Our prospective data demonstrate that the impact of overweight and obesity upon medical care costs in Japan is as large as in Western countries, despite the much lower mean BMI in Japanese populations.

A case of effective gastrostomy for severe abdominal distention due to breathing dysfunction of Rett's syndrome: a treatment of autonomic disorder.

We report a case of 13-year-old-girl with Rett's syndrome and effectiveness of gastrostomy for severe paradoxical respiration, seizures and abdominal distention. Since the age of 3, she was observed to have typical hand-washing movement and autistic behavior. At the age of 8, she began to have hyperventilation and seizures in awake stage. Her symptoms were worse from year to year. At the age of 13, gastrostomy was done to treat severe abdominal distention. Her symptoms were improve dramatically by the gastric air removal through gastrobutton.

Rosai-Dorfman disease presenting with isolated bilateral orbital masses: report of two cases.

Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy) is a rare benign idiopathic proliferative disease of phagocytic histiocytes. Approximately 80% of patients present with painless massive cervical lymphadenopathy. Isolated extranodal involvement is relatively uncommon. Two cases of Rosai-Dorfman disease are reported: one with isolated bilateral orbital involvement and one with marked cervical lymphadenopathy and multiple dural-based and intraventricular masses.

Effects of exercise training on home blood pressure values in older adults: a randomized controlled trial.

OBJECTIVE: To determine the effects of exercise training on the blood pressure (BP) values of older adults, using home blood pressure measurement. DESIGN: Randomized controlled trial. PARTICIPANTS: A total of thirty-nine free-living older adults (including 19 men) aged from 60-81 years with home systolic blood pressure > 120 mmHg and without significant cardiopulmonary-musculoskeletal disease, were randomly allocated to either 25 weeks of exercise training (exercise group) or to a control program (control group). MAIN OUTCOME MEASUREMENTS: Change in the 2-week averages of home systolic and diastolic blood pressure values measured with a validated automatic device before, during and after the intervention period. RESULTS: Compared with the control group, the exercise group showed a significant decrease in values for home systolic blood pressure (maximum between-group difference = 7.7 mmHg, P = 0.003) and home diastolic blood pressure (4.2 mmHg, P = 0.001). These changes were observed for both genders. CONCLUSIONS: Exercise training was effective for older adults in lowering home blood pressure values. This is the first trial to demonstrate the usefulness of home blood pressure measurement in examining the effect of exercise training on blood pressure values.