Intercenter differences in diffusion tensor MRI acquisition

Purpose:

To assess the effect on diffusion tensor (DT) magnetic resonance imaging (MRI) of acquiring data with different scanners.

Materials and Methods:

Forty‐four healthy controls and 36 multiple sclerosis patients with low disability were studied using eight MR scanners with acquisition protocols that were as close to a standard protocol as possible. Between 7 and 13 subjects were studied in each center. Region‐of‐interest (ROI) and histogram‐based analyses of fractional anisotropy (FA), axial (D_ax), radial (D_rad), and mean diffusivity (MD) were performed. The influence of variables such as the acquisition center and the control/patient group was determined with an analysis of variance (ANOVA) test.

Results:

The patient/control group explained ≈25% of data variability of FA and D_rad from midsagittal corpus callosum (CC) ROIs. Global FA, MD, and D_rad in the white matter differentiated patients from controls, but with lower discriminatory power than for the CC. In the gray matter, MD discriminated patients from controls (30% of variability explained by group vs. 17% by center).

Conclusion:

Significant variability of DT‐MRI data can be attributed to the acquisition center, even when a standardized protocol is used. The use of appropriate segmentation methods and statistical models allows DT‐derived metrics to differentiate patients from healthy controls. J. Magn. Reson. Imaging 2010;31:1458–1468. © 2010 Wiley‐Liss, Inc.     

No survival difference after successful 131I ablation between patients with initially low-risk and high-risk differentiated thyroid cancer

Purpose

To compare disease-specific survival and recurrence-free survival (RFS) after successful ¹³¹I ablation in patients with differentiated thyroid carcinoma (DTC) between those defined before ablation as low-risk and those defined as high-risk according to the European Thyroid Association 2006 consensus statement.

Methods

Retrospective data from three university hospitals were pooled. Of 2009 consecutive patients receiving ablation, 509 were identified as successfully ablated based on both undetectable stimulated serum thyroglobulin in the absence of antithyroglobulin antibodies and a negative diagnostic whole-body scan in a follow-up examination conducted 8.1±4.6 months after ablation. Of these 509 patients, 169 were defined as high-risk.

Results

After a mean follow-up of 81±64 months (range 4–306 months), only three patients had died of DTC, rendering assessment of disease-specific survival differences impossible. Of the 509 patients, 12 (2.4%) developed a recurrence a mean 35 months (range 12–59 months) after ablation. RFS for the duration of follow-up was 96.6% according to the Kaplan-Meier method. RFS did not differ between high-risk and low-risk patients (p=0.68). RFS differed slightly but significantly between those with papillary and those with follicular thyroid carcinoma (p=0.03) and between those aged ≤45 years those aged >45 years at diagnosis (p=0.018).

Conclusion

After (near) total thyroidectomy and successful ¹³¹I ablation, RFS does not differ between patients classified as high-risk and those classified as low-risk based on TNM stage at diagnosis. Consequently, the follow-up protocol should be determined on the basis of the result of initial treatment rather than on the initial tumour classification.     

Feasibility of using single photon counting X-ray for lung tumor position estimation based on 4D-CT

Purpose

In stereotactic body radiation therapy of lung tumors, reliable position estimation of the tumor is necessary in order to minimize normal tissue complication rate. While kV X-ray imaging is frequently used, continuous application during radiotherapy sessions is often not possible due to concerns about the additional dose. Thus, ultra low-dose (ULD) kV X-ray imaging based on a single photon counting detector is suggested. This paper addresses the lower limit of photons to locate the tumor reliably with an accuracy in the range of state-of-the-art methods, i.e. a few millimeters.

AV-Reentry-Tachykardie und Wolff-Parkinson-White-Syndrom

The AV-reentrant tachycardia (AVRT) is a supraventricular tachycardia with an incidence of 1–3/1000. The pathophysiological basis is an accessory atrioventricular pathway (AP). Patients with AVRT typically present with palpitations, an on–off characteristic, anxiety, dyspnea, and polyuria. This type of tachycardia may often be terminated by vagal maneuvers. Although the clinical presentation of AVRT is quite similar to AV-nodal reentrant tachycardias, the correct diagnosis is often facilitated by analyzing a standard 12-lead ECG at normal heart rate showing ventricular preexcitation. Curative catheter ablation of the AP represents the therapy of choice in symptomatic patients. This article is the fourth part of a series written to improve the professional education of young electrophysiologists. It explains pathophysiology, symptoms, and electrophysiological findings of an invasive EP study. It focusses on mapping and ablation of accessory pathways.     

The thoughts of breast cancer survivors regarding the need for starting hormone replacement therapy

There is not only a need for scientific data regarding the risk of recurrence of breast cancer by starting hormone replacement therapy (HRT) but also regarding the patients' needs for HRT. OBJECTIVES: To examine the severity of climacteric complaints in breast cancer patients and to examine if they are willing to take HRT. METHODS: In November 2003, a questionnaire was sent to 469 breast cancer survivors. The survey examined on a scale base the severity of climacteric complaints and the patient's opinion on starting HRT. RESULTS: More than 76% of the patients complained that they experience or had experienced hot flushes or night sweating. More than half (53%) of this group found the inconvenience severe to extreme, affecting the patient's quality of life. A majority (80.5%) patients who had already taken HRT, found that it improved their quality of life substantially. When the results of observational studies were explained regarding HRT in breast cancer survivors, a majority said they would take or would consider taking HRT (57.9%). CONCLUSION: While physicians are more reserved in prescribing HRT in breast cancer survivors, a combination of severe symptomatic climacteric complaints and the willingness of the patient to be treated should at least result in a "consideration" of prescribing HRT.