Quantification of the Pain and Physical Burden Experienced during Positioning for Craniocaudal Imaging in Mammography, Evaluated by Measurement of Muscle Activity

Mammography is carried out in a special position, i.e. “an image is taken while the breast is compressed, stretched and kept in a fixed position”. The purpose of this study was to demonstrate quantitatively and qualitatively the physical and psychological burden due to positioning and breast compression during mammography. Muscle activity of each part of the body during positioning for the standard imaging method, to obtain craniocaudal (CC) view images, was measured in 15 adult females using surface EMG. The associated pain was analyzed using visual analogue scale (VAS) scores. During positioning for the CC view, muscle activity was highest in the biceps (24.44 iEMG/s) followed by the trapezius (17.78 iEMG/s) on the imaging side. Muscle activity of the biceps and the sternocleidomastoid on the imaging side showed significant differences compared with pre-imaging activity (biceps P < 0.031, sternocleidomastoid P < 0.005). The pain during mammography was rated as moderate to severe pain (VAS = 3.3 - 6.7) for CC views. As a result, the activities of not only the muscles directly involved in mammography positioning but also those indirectly involved were high as compared with the normal state. Measurement of muscle activity during mammography is expected to be used effectively, such as in the care to reduce pain for the subjects.

Pupil Size Measurement and Sucrose Ingestion for Quantifying and Decreasing Burden of Women during Mammography

Many women feel a physical burden, which usually appears as a pain, during mammography. We examined the pain-related pupil dilation response during mammography. Twenty-four healthy women participated in the examination. They were randomly assigned to water group or sucrose group. Water group and sucrose group ingested distilled water and a sucrose solution during mammography, respectively. Their pupil sizes were measured during mammography excluding X-ray irradiation. The subjective intensity of pain during mammography was also assessed using visual analogue scales (VAS). The mean pupil diameter was 2.99 mm in relaxation phase before mammography, while it was 3.15 mm in a few seconds after breast compression (pressure phase). The difference between the two was statistically significant (p p < 0.01). These results suggest that we may be able to assess objectively the degree of pain associated with mammography and sweet taste stimuli may be effective to alleviate a women’s burden received during mammography.

Investigation of Noise-Resolution Tradeoff for Digital Radiographic Imaging: A Simulation Study

In digital radiographic systems, a tradeoff exists between image resolution (or blur) and noise characteristics. An imaging system may only be superior in one image quality characteristic while being inferior to another in the other characteristic. In this work, a computer simulation model is presented that is to use mutual-information (MI) metric to examine tradeoff behavior between resolution and noise. MI is used to express the amount of information that an output image contains about an input object. The basic idea is that when the amount of the uncertainty associated with an object before and after imaging is reduced, the difference of the uncertainty is equal to the value of MI. The more the MI value provides, the better the image quality is. The simulation model calculated MI as a function of signal-to-noise ratio and that of resolution for two image contrast levels. Our simulation results demonstrated that MI associated with overall image quality is much more sensitive to noise compared to blur, although tradeoff relationship between noise and blur exists. However, we found that overall image quality is primarily determined by image blur at very low noise levels.

Effects of Communication Robot on Distress Reduction in Mammography

Mammography is obviously useful for the early detection and diagnosis of breast diseases in women. However, it usually involves anxieties and pains. This paper aimed to explore effects of the communication robot on distress reduction in mammography. Nineteen healthy women participated in the examination. They were randomly assigned to either an experimental group (n = 9) or a control group (n = 10). The participants in the experimental group talked and played with a communication robot before mammography. PALRO (FUJISOFT Inc., Tokyo, Japan) was used as the communication robot, which was a chatty, comforting robot. PALRO can communicate with the human and has several specific applications such as dancing, singing and talking about knowledge of various things. Autonomic nervous activities were observed before and during mammography. Degrees of subjective pain associated with mammography were also assessed using a visual analogue scale (VAS). As a result, autonomic nervous activities between the experimental group and the control group were not significantly different. Unfortunately, the communication robot did not help to intensify parasympathetic nerve activities, which became dominant at rest or a relaxed state. On the other hand, the VAS scores for pain in the experimental group were significantly smaller than ones in the control group (p < 0.01). This result suggested that the communication robot was useful for relieving degrees of subjective pain associated with mammography. In conclusion, communication with a robot before mammography would yield positive emotions and it would be related to the pain alleviation during mammography.

Dose Reduction by the Use of a Wavelet-Based Denoising Method for Digital Radiography

The primary purpose of this paper is to provide a novel wavelet-domain method for digital radiography with low dose examination. Approach of this study is an improved wavelet-transform-based method for potentially reducing radiation dose while maintaining clinically acceptable image quality. The wavelet algorithm integrates the advantages of wavelet-coefficient-weighted method and the existing Bayes Shrink thresholding method. In order to confirm the usefulness of the proposed method, the resolving and noise characteristics of the processed computed radiography images were measured. In addition, variations of contrast and noise with respect to radiation dose were also examined. Finally, to verify the effect of clinical examination, visual evaluations were also performed in lower abdominal area using phantom. Our quantitative results demonstrated that our wavelet algorithm could improve resolution characteristics while keeping the noise level within acceptable limits. Visual evaluation result demonstrated that the proposed method was superior to other published methods. Our proposed method recognized effect on decreasing in exposure dose in lower abdominal radiographs. As a conclusion, our proposed method’s performance is better when compared with that of the 3 conventional methods. The proposed method has the potential to improve visibility in radiographs when a lower radiation dose is applied.

The Effect of Humorous Stimuli on Alleviating Pain during Mammography: A Preliminary Study

Mammography is widely performed as a standardized procedure for breast cancer screening;however, women often feel some degree of pain during this procedure. Currently, there are limited options available for alleviating pain related to mammography. A non-medicinal approach to the alleviation of pain involves the effects of laughter on physical and psychological wellbeing. We therefore examined the possibility that humorous stimuli would alleviate the physical burden on women undergoing mammography. We assessed 29 women, 15 women received only conventional mammography (neutral group), while 14 women (humor group) watched a funny video during the same examination. The intensity of pain experienced during mammography was assessed by visual analogue scale (VAS) and the VAS results showed a statistically significant difference (P = 0.007) between the two groups, with the humor group experiencing less pain. In an additional experiment, 14 women in the humor group also underwent conventional mammography without exposure to the funny video and pain was assessed by VAS. We found that the pain experienced during conventional mammography without the funny video was significantly greater than the pain experienced during the same mammography but with the funny video (P = 0.047). These findings suggested the possibility of alleviating pain during mammography by humorous stimuli.

Effects of mammography positioning on the autonomic nervous function

The physical and psychological burden on patients during mammography was analyzed using the autonomic function index in 34 adult females. The indices included heart rate (HR), high frequency (HF) of the R-R interval on an electrocardiogram, and the ratio of HF to LF (low frequency) (LF/HF). HR is an indicator of the degree of mental and physical activity, HF indicates the parasympathetic index and LF/HF indicates the sympathetic index. For the mediolateral oblique (MLO) view in mammography, autonomic function indices were measured before and during mammography. Statistical analysis was performed by the Mann-Whitney U test and the significance level was set at 5%. The autonomic function indices were compared before and during mammography and all showed no significant differences. The average value before imaging and the reference value at rest were compared. The results showed that HR increased 1.3-fold, HF increased 0.4-fold, and LF/HF increased 3.2-fold over reference values. Chronological changes during mammography showed that HF increased and LF/HF decreased from 120 seconds after the start of imaging. From these observations, it is evident that the state before mammography is not the same as the resting state and that the sympathetic index is dominant before imaging. They also suggest that some aspects of the psychological burden experienced during mammography are not due to the pain of breast compression alone.

Using mutual information to evaluate performance of medical imaging systems

Information on physical image quality of medical images is important for imaging system assessment in order to promote and stimulate the development of state-of-the-art imaging systems. In this paper, we present a method for evaluating physical performance of medical imaging systems. In this method, mutual information (MI) which is a concept from information theory was used to measure combined properties of image noise and resolution of an imaging system. In our study, the MI was used as a measure to express the amount of information that an output image contains about an input object. The more the MI value provides, the better the image quality is. To validate the proposed method, computer simulations were per- formed to investigate the effects of noise and resolution degradation on the MI, followed by measuring and comparing the performance of two imaging systems. Our simulation and experimental results confirmed that the combined effect of deteriorated blur and noise on the images can be measured and analyzed using the MI metric. The results demonstrate the potential usefulness of the proposed method for evaluating physical quality of medical imaging systems.

Quantitative Analysis of Pain during Mammography Using Electrical Stimulation

In order to quantitatively measure the degree of pain during mammography, we used a visual analog scale (VAS) and a device for quantitative analysis of perception and pain and performed regression analysis of the relationship between pain degree and VAS score. Twenty-four subjects underwent a typical mammogram and we found no correlation between pain degree using the device compared with VAS scoring. It is presumed that the system enables quantitative measurement and comparison more accurately than subjective markers such as VAS in quantitation of a pain produced in an examination with clearly defined physical size (such as mammography).