The Effect of the Base of Support on Anticipatory Postural Adjustment and Postural Stability

PURPOSE: This study was to identify the anticipatory postural adjustment (APA) mechanism which is represented by the onset time of trunk muscles and the displacement of the center of pressure (COP) according to the different base of support (BOS) during upper extremity movement. METHODS: Thirty healthy subjects (14 males, 16 females) participated in this study. The movement was performed for 10 trials during each of various BOS (shoulder - width double leg stance, narrow base double leg stance, tandem stance, non-dominant single leg stance) at the 1.2 Hz frequency. Electromyography was used to measure muscle onset time and biorescue was used to measure characteristics of the displacement of COP. Surface bipolar electrodes were applied over the right deltoid anterior, right latissimus dorsi, both rectus abdominis, both internal oblique and both erector spinae. The data were analyzed by repeated one-way ANOVA and Duncan's post hoc test. RESULTS: The study has revealed following. There were significant differences with muscle onset time in each BOS (p<0.01). There were significant differences in characteristics of the COP in each BOS (p<0.01). CONCLUSION: The study found that the more narrowed the basis requires the more rapid anticipatory postural control in contralateral postural muscle when the upper extremity movement is performed.

The Short Breath-Hold Technique, Controlled Aliasing in Parallel Imaging Results in Higher Acceleration, Can Be the First Step to Overcoming a Degraded Hepatic Arterial Phase in Liver Magnetic Resonance Imaging: A Prospective Randomized Control Study.

OBJECTIVE: The aim of this study was to assess whether a short breath-hold technique can improve hepatic arterial phase (HAP) image quality in gadoxetic acid-enhanced magnetic resonance (MR) imaging compared with a conventional long breath-hold technique. MATERIALS AND METHODS: Institutional review board approval and patient consent were obtained for this prospective randomized control study. One hundred nineteen patients undergoing gadoxetic acid-enhanced MR imaging were randomly assigned to groups A or B. Group A patients underwent an 18-second long breath-hold MR technique (conventional VIBE [volumetric interpolated breath-hold examination] technique with GRAPPA [generalized autocalibrating partially parallel acquisition]), and group B patients underwent a 13-second short breath-hold MR technique (VIBE technique with CAIPIRINHA [controlled aliasing in parallel imaging results in higher acceleration]). Respiratory-related graphs of the precontrast and HAP were acquired. The breath-hold degree was graded based on the standard deviation (SD) value of respiratory waveforms. Gadoxetic acid-related dyspnea was defined as when the SD value of the HAP was 200 greater than that of the precontrast phase without degraded image quality in the portal and transitional phases (SD value of the HAP - SD value of the precontrast phase). The overall image quality and motion artifacts of the precontrast and HAP images were evaluated. The groups were compared using the Student t or Fisher exact test, as appropriate. RESULTS: The incidence of breath-holding difficulty (breath-hold grades 3 and 4) during the HAP was 43.6% (27/62) and 36.8% (21/57) for group A and B, respectively. The SD value during the precontrast phase and the SD value difference between the precontrast and HAP were both significantly higher in group A than in group B (P = 0.047 and P = 0.023, respectively). Gadoxetic acid-related dyspnea was seen in 19.4% (12/62) of group A and 7.0% (4/57) of group B. Group B showed better precontrast and HAP image quality than group A (P < 0.001). Degraded HAP (overall image quality ≥4) was observed in 9.7% (6/62) and 3.5% (2/57) of group A and B, respectively. CONCLUSIONS: The short breath-hold MR technique, CAIPIRINHA, showed better HAP image quality with less degraded HAP and a lower incidence of breath-hold difficulty and gadoxetic acid-related dyspnea than the conventional long breath-hold technique.

Hepatic Arterial Phase in Gadoxetic Acid-Enhanced Liver Magnetic Resonance Imaging: Analysis of Respiratory Patterns and Their Effect on Image Quality.

OBJECTIVE: The aims of this study were to objectively evaluate patient respiration and breathing change after contrast injection and to assess its potential impact on image quality for the hepatic arterial phase in gadoxetic acid-enhanced magnetic resonance imaging. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board, and the requirement for informed consent was waived. One hundred fifty-four patients underwent gadoxetic acid-enhanced liver magnetic resonance imaging with a 13-second breath-hold hepatic arterial phase. During the acquisition of precontrast and hepatic arterial phases, the respiratory motion signal was acquired and graded on a 4-point scale based on the SD of the respiratory waveform, with the highest grade indicating the worst breath-hold. Breath-holding grades 3 and 4 for the hepatic arterial phases were considered as breath-holding difficulty during the hepatic arterial phase. Gadoxetic acid-related dyspnea was defined as when the SD value of respiratory waveform during the hepatic arterial phase was 200 greater than that of the precontrast image. Then, the precontrast and hepatic arterial phase images were evaluated with respect to overall image quality and motion artifact using a 5-point scale, with the highest score indicating the worst image quality. In the hepatic arterial phase, the correlation between breath-holding degree and image quality parameters was evaluated using Pearson correlation. The differences in mean image quality scores between patients with and without gadoxetic acid-related dyspnea were evaluated using Student t test. RESULTS: Based on the analysis of the respiratory waveforms, the incidence of breath-holding difficulty during the hepatic arterial phase was 23.4% (33/154), and the incidence of gadoxetic acid-related dyspnea was 6.5% (10/154). By image analysis, the incidence of a degraded hepatic arterial phase (overall image quality score ≥4) was 5.2% (8/154). During the hepatic arterial phase, the breath-holding degree correlated with overall image quality and motion artifacts (r = 0.564 and 0.578, respectively). Patients with gadoxetic acid-related dyspnea showed significantly worse image qualities of the hepatic arterial phase than patients without gadoxetic acid-related dyspnea (all, P < 0.001), although image qualities for the precontrast image were not statistically significant between the 2 groups (all, P > 0.05). CONCLUSIONS: The objective analysis of respiratory patterns during a breath-hold is feasible and useful for evaluating gadoxetic acid-related dyspnea and its effect on image quality analysis.

Gray scale and power Doppler study of biopsy-proven Kikuchi disease.

OBJECTIVES: Kikuchi disease is a benign, self-limiting cause of cervical lymphadenopathy. It can show sonographic features similar to those of other common causes of lymphadenopathy. The purpose of this study was to characterize the sonographic features of Kikuchi disease that can contribute in differentiating between Kikuchi disease and other diseases causing cervical lymphadenopathy. METHODS: Sonographic findings of 175 patients with biopsy-proven Kikuchi disease were retrospectively reviewed. The mean age of the patients was 27.3 years, and the female to male ratio was 3.5:1. All patients had undergone sonographically guided core biopsy. Pathologic findings were classified into proliferative (n = 57), necrotizing (n = 109), and xanthomatous (n = 9) types. On gray scale sonography, lymph nodes were assessed by their size, shape (shortest/longest axis ratio), location, echogenicity, presence of conglomeration, gross necrosis, calcification, echogenic nodal hilum, and increased perinodal echogenicity. The vascular pattern was assessed on power Doppler imaging. RESULTS: The mean maximum diameter of the lymph nodes was 1.6 cm. Forty-four percent of them (77 of 175) were oval (shortest/longest axis ratio, 0.5-0.7) and 48% (84 of 175) were elongated (shortest/longest axis ratio, <0.5). Most were located in levels II and V. Seventeen lymph nodes showed gross necrosis, and none showed calcification. One hundred fifty-two lymph nodes (86.8%) had an echogenic hilum, and 76% (133 of 175) showed increased perinodal echogenicity. Increased perinodal echogenicity was seen in 93.5% of the necrotizing type (102 of 109) and 43.8% of the proliferative type (25 of 57); the difference between the two types was statistically significant (P = .001). Normal (n = 161), displaced (n = 13), and absent (n = 1) hilar vascularity was seen on power Doppler studies. CONCLUSIONS: Sonographic findings of Kikuchi disease can contribute to the differentiation between Kikuchi disease and other causes of cervical lymphadenopathy.

Can MR Imaging contribute in characterizing well-circumscribed breast carcinomas?

Most well-circumscribed breast masses are benign lesions such as cysts, fibroadenomas, and intramammary lymph nodes. Nevertheless, 10%-20% of breast malignancies are well-circumscribed masses, and these malignancies include papillary, mucinous, medullary, and metaplastic carcinomas, as well as malignant phyllodes tumors. Therefore, it is important to differentiate these well-circumscribed breast malignancies from benign breast lesions, but it is not easy to do so with conventional imaging modalities such as mammography and ultrasonography (US). As an emerging adjunctive imaging method, magnetic resonance (MR) imaging has substantial potential in characterizing well-circumscribed breast carcinomas. Analysis of the lesion signal intensity on nonenhanced T2-weighted MR images, determination of the enhancement pattern, and kinetic curve assessment can greatly help differentiate malignant from benign well-circumscribed breast lesions. Therefore, breast MR imaging can play a substantial role in distinguishing between well-circumscribed benign and malignant breast lesions, especially in cases that are difficult to diagnose by using conventional imaging. In this article, the MR imaging findings of the subtypes of well-circumscribed malignant breast lesions-intracystic papillary carcinoma, invasive papillary carcinoma, mucinous carcinoma, medullary carcinoma, metaplastic carcinoma, and malignant phyllodes tumor-are described and correlated with the histopathologic, mammographic, and US findings.