Impact of Repetitive Transcranial Magnetic Stimulation with Computerized Cognitive Enhancement Training on Change in Cognitive Function of Mild Cognitive Impairment Patients : Existing, Sham Treatment Controlled, Pilot Study

An Empirical Study on Quantitative Evaluation of Cognitive Function / 의학물리

Imaging studies using MRI, PET, and/or MEG have been primary evaluation methods to quantitatively assess cognitive function. Recent advances in computational technology and information technology may allow a novel evaluation methodology to quantitate cognitive function more cost-effectively. In this study, we developed a software package composed of a series of tests to evaluate cognitive ability combined with a user-friendly touch screen input device. This cognitive assessment tool can quantitate concentration, numeric memory, associative memory, topological memory, visual and muscular reaction, and acoustic reaction over a relatively short testing time. We performed an empirical study on eighty normal subjects aged 20 and 59 years old using the developed evaluation methods. Age-related cognitive deterioration after 40 years old was confirmed. There was no difference in cognitive ability between male and female in the same age group. This study demonstrates the feasibility of a simple but effective evaluation software tool to quantitatively assess cognitive ability. This methodology may provide improved accessibility and reduced costs to perform cognitive function studies to compare between various subject groups.

Experimental Study of 99mTc-Ciprofloxacin (Infecton) Imaging for the Diagnosis of the Acute Appendicitis

PURPOSE: Acute appendicitis is the most common disease requiring abdominal surgery, but for atypical clinical findings, a preoperative diagnosis is difficult and the frequency of a false positive and false negative diagnosis is high. The authors compared the diagnostic accuracy of a Technetium-99m-ciprofloxacin scan with that of the other diagnostic tools and evaluated its potential for clinical applications. METHODS: Seventeen patients were among those patients who visited the emergency room due to right lower quadrant (RLQ) pain were selected for this study. The decision for primary treatment was based on the clinical findings (RLQ pain, nausea, tenderness, rebound tenderness, leukocytosis, etc) and the radiological findings (abdominal ultrasonogram, abdominal computed tomography, etc). The 99mTc-ciprofloxacin scan was conducted regardless of the decision above. For the patients who underwent surgery, the final diagnosis of acute appendicitis was based on the pathologic result and for patients who did not undergo surgery, the final diagnosis was determined by the clinical course. RESULTS: Seventeen patients were enrolled in this study (7 males, 10 females). The patient's age ranged from 8 to 71 years and the average age was 29.2 years. The diagnostic accuracy of acute appendicitis is presented in order of the clinical findings, the radiological findings and the 99mTc- ciprofloxacin scan as follows: The sensitivity was 100%, 90.9% and 100%; the specificity rates was 33.3%, 50% and 67%; the positive predictive value was 87.5%, 90.9% and 93%; the negative predictive values was 100%, 50% and 100%; the false positive rate was 66.7%, 50% and 33.3%; the false negative rate was 0%, 9% and 0%. The respective p-values for the correlation between these results and the final diagnosis were 0.021, 0.049 and 0.002. CONCLUSION: A 99mTc-ciprofloxacin scan can decrease the false positive and the false negative rate and increase the diagnostic accuracy of acute appendicitis patients.

Analysis of Endcap Effect for MRI Birdcage RF Coil by FDTD Method

PURPOSE: B1 field of birdcage RF (radiofrequency) coil that is used most for brain imaging in magnetic resonance imaging (MRI) decreases toward endring from the coil center. We investigated how much RF B1 homogeneity effect the endcap shield brings form the coil center as it towards to endcap region. MATERIALS AND METHODS: We compared RF B1 field distribution by each finite difference time domain (FDTD) simulations for lowpass, highpass and hybrid birdcage RF coils. We selected the highpass birdcage RF coil that was the highest RF B1 field condition as simulation result, and studied how much RF B1 homogeneity effect was occurred when endcap shield was applied to endring area. RESULTS: B1 field of the highpass birdcage RF coil was higher than other birdcage RF coil types as simulation result. However, the RF B1 homogeneity was lower than other coil types. RF B1 field of highpass birdcage RF coil with endcap shield is similar with RF B1 field of hybrid birdcage RF coil and the overall RF B1 homogeneity in sagittal direction was better. CONCLUSION: In this paper, proposed method can apply improving RF B1 homogeneity of RF coil in clinical examination.

High Resolution MR Images from 3T Active-Shield Whole-Body MRI System

PURPOSE: Within a clinically acceptable time frame, we obtained the high resolution MR images of the human brain, knee, foot and wrist from 3T whole-body MRI system which was equipped with the world first 3T active shield magnet. MATERIALS AND METHODS: Spin echo (SE) and Fast Spin Echo (FSE) images were obtained from the human brain, knee, foot and wrist of normal subjects using a homemade birdcage and transverse electromagnetic (TEM) resonators operating in quadrature and tuned to 128 MHz. For acquisition of MR images of knee, foot and wrist, we employed a homemade saddle shaped RF coil. Typical common acquisition parameters were as follows: matrix= 512x512, field of view (FOV) = 20 cm, slice thickness = 3 mm, number of excitations (NEX) = 1. For T1-weighted MR images, we used TR= 500 ms, TE = 10 or 17.4 ms. For T2-weighted MR images, we used TR=4000 ms, TE = 108 ms. RESULTS: Signal to noise ratio (SNR) of 3T system was measured 2.7 times greater than that of prevalent 1.5T system. MR images obtained from 3T system revealed numerous small venous structures throughout the image plane and provided reasonable delineation between gray and white matter. CONCLUSION: The present results demonstrate that the MR images from 3T system could provide better diagnostic quality of resolution and sensitivity than those of 1.5T system. The elevated SNR observed in the 3T high field magnetic resonance imaging can be utilized to acquire images with a level of resolution approaching the microscopic structural level under in vivo conditions. These images represent a significant advance in our ability to examine small anatomical features with noninvasive imaging methods.

A Preliminary Results of Acoustic Noise Effect due to Gradient Pulsing in Functional MRI

PURPOSE: In functional MRI(fMRI), the acoustic noise effects of gradient pulsing are analyzed with two different combinations of readout and phase-encoding gradients for sagittal-view images. MATERIALS AND METHODS: Series of sagittal-view EPI images for fMRI obtained from five healthy volunteers. In order to show the effect of gradient pulsing noise, this study was duplicated for the Y readout / Z phase-encoding gradients and the Z readout / Y phase-encoding gradients. The first 7 images were obtained with visual stimulation. This sequential paradigm without and with visual stimulation was repeated 4 times, and was followed by the last 7 images being obtained without visual stimulation. In order to compare the visual cortex activation according to the combination of readout and phase-encoding gradients, the number of activated pixels and the average intensities of the activated pixels were analyzed, where the total activation is defined by multiplying the number of activated pixels by the average intensities of the activated pixels. RESULTS: The experimental results show that the combination of Z readout and Y phase-encoding gradients produce larger visual cortex activation than the combination of Y readout and Z phase-encoding gradients when a sagittal-view fMRI is performed. CONCLUSION: This experiment result represents that visual cortex response can be affected by acoustic noise. Therefore, the combination of the Z readout and Y phase encoding gradients is efficient for sagittal view fMRI because it has less acoustic noise.

A Case of Femoral Artery Pseudoaneurysm Treated with Compression Guided by Color Doppler Ultrasound

Pseudoaneurysm is one of the undesirable complications of interventional cardiology procedures involving peripheral puncture site. Nowadays, it is not uncommon as a consequences of more complex interventional preocedures, larger catheters and prolonged anticoagulation treatment. Surgical repair has been mainstay of treatment for pesudoaneurysm. However, sucessful closures of pseudoaneurysms have been reported recently by using direct compression guided by color doppler ultrasound. We report a case of pseudoaneurysm in femoral artery, which was developed at the right inguinal puncture site in 38 year old male patient with unstabel angina who had received continuous intravenous infusion of heparin and had undergone coronary angiography treated successfully with direct compression guided by color doppler ultrasound.