Assessment of Osteoporosis Based on Changes in SNR and ADC Values on MR Diffusion Weighted Images / 의학물리

This study tested how S/N (Signal to Noise Ratio) ratios and ADC (apparent diffusion coefficient) values vary with different T-scores in a group of patients with osteoporosis. Based on DEXA (Dual Energy X-ray Absorptiometry) T-scores for L1?L4 for two groups of subjects consisting of 30 healthy people without osteoporosis and 30 patients who came for treatment of waist (lumbar or low back) pain and were suspected to have osteoporosis as judged from the simple X-ray findings, this study classified every spine into two groups of osteoporosis and osteopenia. Signal intensity measurements were made in the four regions of L1 to L4 on diffusion-weighted MR images obtained using 1.5T MR scanner, while ADC measurements were obtained from ADC map images. As an approach for quantitative analysis, the comparison of the variances in S/N ratios and ADC values for varying T-scores in the selected regions of interest was carried out based on averaged T-scores, S/N ratios, and ADC values. Also, the variances in S/N ratios and ADC values for each of the groups of osteoporosis and osteopenia, which were classified into by T-scores, were compared. For qualitative analysis, a careful naked eye examination of signal intensity differences in the area of L4 was made on T1-weighted sagittal images for each of the healthy (normal), osteopenia, and osteoporosis groups. In the qualitative analysis, it was found that for both the osteopenia group and the osteoporosis group, as T-scores deceased, the S/N ratios on diffusion-weighted MR images also decreased, with the greatest decrease in the S/N ratio found in the osteoporosis group. Additionally, among the three groups, the lowest S/N ratio was found in the osteoporosis group. With respect to ADC map, it was found that for both the osteopenia group and the osteoporosis group, as T-scores deceased, the ADC values on diffusion-weighted MR images also decreased, with the greatest decrease in the ADC values found in the osteoporosis group. Additionally, among the three groups, the lowest ADC value was found in the osteoporosis group. On the other hand, in the qualitative analysis, the osteoporosis group showed the highest signal intensity. Additionally, among the three groups, the lowest signal intensity was found in the healthy (normal) group. It was found that as osteoporosis progressed, S/N ratio and ADC decreased, whereas signal intensity increased on T1-weighted images. Also, in diagnosing osteoporosis, MRI tests turned out to be (more) effective.

Problems with interpretation of primary diagnostic tests for impotence / 대한비뇨기과학회지

We analyzed the practical problems and factors which affect making the correct differential diagnosis in the interpretation or test results from the nocturnal penile tumescence (NPT) test and erotic stimulation test (EST). This was done to provide better information for higher diagnostic accuracy in the clinical application of these tests. The followings are the results of NPT tests and EST identifying the factors affecting correct differential diagnosis by comparison the other differential diagnostic methods. The overall sensitivity of NPT test (Number: 114 total patients) was 82%. 21 cases (18%) could not be diagnosed correctly due to traction of the sensor (12 cases, 10%) and sleep disturbance (9 cases, 8%). The overall sensitivity of EST (Number: 174 total patients) without considering the degree of patient`s sexual drive to erotic stimulation was 77%. 40 cases (23%) could not be diagnosed correctly due to tolerance to pornographic film (17 cases, 10 %), discomfort by the body attachments (14 cases, 8%) and traction of the sensor (9 cases, 5%). However, higher sensitivity (90%) and lower rate of incorrect diagnosis (10% ) were observed in 119 patients who showed Grade II or III (moderate to good) sexual drive to erotic stimulation. The results suggest that undesirable factors in the primary screening methods, traction of sensor, sleep disturbance in NPT test, and tolerance to pornographic film, discomfort by the body attachments, traction of sensor in EST must be taken into consideration when interpretation of test results is being performed.

Clinical experience of adverse drug reaction in gadolinium-DTPA enhancement of MRI

Gadopentetate dimeglumine(Gd-DTPA) has low toxicity and good tolerance and it is said that the observed adverse drug reaction of Gd-DTPA is compatible to those of iodinated nonionic contrast media. The overall incidence of adverse drug reaction of Gd-DTPA is even lower than those of iodinated nonionic contrast media. Then, the possibility of potential adverse drug reaction of these contrast media is not fully known and recently, many authors have a growing interest in this point. We have taken 2501 cases of MRI and exccure 1467 cases of Gd-DTPA enhancement scaning(58.7%0 and experienced 12 cases of adverse drug reaction(11 cases: mild reaction. 1 case: severe anaphylactic shock)and the overall incidence of our adverse drug reaction of Gd-DTPA was 0.8%. In conclusion, the adverse drug reaction of Gd-DTPA is not rare and the severe adverse drug reaction of Gd-DTPA may occur. So, the possibility of adverse drug reaction after Gd-DTPA injection should always be kept in mind, especially when the patient has a history of reaction to contrast material, allergy(particularly asthma) and cardiac disease. For the safe use of Gd-DTPA, well trained personnel and nearby emergent care facilities should be available.