Transient ischemic attacks (TIAs) is a syndrome resulting from brain ischemia lasting less than 24 hours. The mechanisms of TIAs may be similar to those of cerebral embolism and thrombosis, and thus TIAs may be followed by cerebral infarction. Despite the availability of CT scanning, the diagnosis and management of TIAs continue to be difficult. Recently SPECT has been advocated as a diagnostic imaging modality. We performed Tc-99m-HMPAO regional cerebral blood flow (rCBF) SPECT in 24 patients with the clinical diagnosis of TIAs to assess its ability to detect early changes of rCBF, and determine the diagnostic value. Ten men and fourteen women with an average of 51 years (range; 27-74 years) were included. All but 8 patients had normal brain CT prior to SPECT. The two patients had moderate degree of brain atrophy and the 6 patients nonspecific calcifications. Eighteen of the 24 patients had abnormal Tc-99m-HMPAO rCBF SPECT. Fifteen had unilateral involvement and the other three had bilateral involvements. Seventy-five percents of the defects were found in the left cerebral hemisphere. According to the distribution of the lesions (total number: 34 lesions), fourteen were in the parietal, eight in the temporal, and the remainders were elsewhere. Tc-99m-HMPAO rCBF SPECT is sensitive in detecting rCBF abnormalities in patients with TIAs, and represent the most accurate diagnostic tool available in the diagnosis of TIAs.

Regional cerebral perfusion was evaluated in 15 normal controls by single photon emission computed tomography using $^{99m}Tc$ HM-PAO. For quantitative analysis, 13 pairs of homologous region of interest (ROI) were drawn on three transverse slices matching the vascular territories and cerebral cortices, and normal values of 3 semiqunatitative indices including 'Right to left ratio'(R/L ratio), 'Regional index'(RI), and 'Region to cerebellum ratio'(R/cbll ratio) were calculated. Mean values of R/L ratios of homotogous regions were ranged from 0.985 to 1.023, and mean ${\pm}2$ s.d. of all regions did not exceed 11% of mean. Significant difference of RIs (mean count per voxel of a ROI/mean count per voxel of total ROIs) between regions were found (p<0.001) with highest values in occipital cortex and cerebellum. After attenuation correction, RIs in deep gray, cranial portion of anterior cerebral artery and vascular territories in the 2nd slice increased significantly (p < 0.05-0.001), but vise versa in other ROIs. Region to cerebellum ratios also showed regional difference similar to RIs.

1983년 1월 부터 1987년 12월까지 5년간 부산의 세곳 대학병원(부산의대, 고신의대, 인제의대)에서 병리조직학적으로 확진된 갑상선암 629예중 병력지 관찰이 가능하였던, 478예를 분석하여 1988년 보사부에서 발행한 Five Years' Report for Cancer Registry Programmme in Republic of Korea (1982 7. 1$\sim$1987. 6.30)의 발생빈도와 비교하였으며, 478예중 311예의 갑상선주사 소견을 분류하여 다음과 같은 결과를 얻었다. 1) 전체 악성암에 대한 갑상선암의 발생빈도는 2.54%(629/24.749)이었으며 이는 한국인에 있어서의 발생빈도와 거의 같았다(2.5%). 2) 여자에서 5배 이상 발생하여 (1 : 5.64) 이것 역시 한국인에서의 성별빈도와 매우 유사하였다(1 : 5.22). 3) 연령분포는 10세에서 91세까지로서 87.03%가 20세에서 59세 사이에 있었다. 4) 유두상암이 가장 흔하였고(78.24%),다음이 여포상암(14.44%) 그 다음이 미분화암(22.30%) 이었다. 5) 갑상선주사 소견상 대부분의 암은 solitary cold nodule을 보였다(82.96% : 258/311).

Visual assessment of regional wall motion abnormality (RWMA) by gated blood pol scan (GBPS) serves as an useful parameter in the diagnosis, functional evaluation, and follow up in various clinical settings, but are still subject to some inherent limitations. On important problem may be the interobserver as well as intraobsever variation that may well be present due to the subjective nature of the interpretations. This study was carried out to determine the reliability and reproducibility of visual assessments made in GBPSs, and to observe the degree to which the results would be influenced by observer variation. Fifty two patients with coronary heart disease had resting GBPS and contrast ventriculography within 4 days appall. Contrast ventriculography-showed normal wall motion in 6 patients and the remaining 46 had RWMA in one or more segments. The anterior and left anterolateral views of all 52 GBPSs were analyzed by three independent observers, who selected from 5 scales, their level of confidence that there was RWMA in that segment. Reciever operating characteristic (ROC) curves for each analysis was plotted and the area under the curve $(\theta)$ was used as a parameter representing each observer's performance in his interpretations. The findings of contrast ventriculographies were used as the standard for RWMA. The apical and inferoapical segments showed the best correlation with contrast ventriculography ($\theta=0.90-0.94$, 0.81-0.94, respectively), and the inferior wall showed the poorest correlation $(\theta=0.70-0.74)$. The interpretations of the inferior, septal, apical, and posteroinferior, segments showed no difference between the observers, but there was significantly better performance in assessment by observer A compared to that by B or C for the anterolateral segments ($\theta=0.87$, 0.78, 0.76, respectively. p<0.01 for A vs B, p<0.05 for A vs C), as well as when all segments were considered altogether ($\theta=0.88$, 0.83, 0.82, respectively. both p<0.05). This was also true for the infero-apical segment between A and C ($\theta=0.09$, 0.81, p<0.05). The intraobserver variation, however, did not appear significant, with only the inferior segment for observer B showing any significant difference when observer A and B repeated the analysis 10 days latter. There was no difference in assessing dyskinesia, with all observers showing a high performance ($\theta=0.98$, 0.87, 0.97, respectively). The visual assessment of left ventricular ejection fraction by all three observers correlated well with the calculated value from a semiautomated method (Spearman's r = 0.91, 0.83, 0.83. p<0.01, p<0.05, p < 0.05). The assessment of LV and RV size also correlated well between the three observers (Kendall's w = 0.80, 0.51, p<0.01 for both left and right ventricles). The above findings suggest that RWMA visually assessed by GBPS correlates well with that done by contrast ventriculography. And although the observer's experience or skill may influence the results in certain segments, visual analysis of GBPS may serve as a reliable and reproducible means for evaluating ventricular function.

Esophageal transit of radionuclide was quantitatively analyzed in 29 patients with dermatomyositis-polymyositis. Fourteen patients (48.3%) showed retention of tracer in oropharynx. The mean value of percent retention of oropharynx was $15.5{\pm}16.6%$. Esophageal dysfunction was found in 19 patients (65.5%). Among them 4 showed mild, 12 showed moderate and 3 showed severe esophageal dysfunction. Dysphagia was found in 11 patients (37.9%), which was closely related to percent retention of oropharynx.Quantitative analysis of esophageal transit of radionuclide seemed to be a useful technique for evaluation of dysphagia in patients with dermatomyositis-polymyositis.

To observe the effect of gastric filling on the images of hepatic scintigraphy, we performed hepatic scintigraphy using $^{99m}Tc-tin$ colloid in twenty patients both in the fasting state and after meal, and made the visual comparison of both images. We found that gastric filling could cause some of the following changes in individual patients. 1) In the anterior view, the distance between the liver and the spleen increased and the interlobar notch of the inferior hepatic border was obliterated. The spleen was displaced downwards, its radioactivity in the upper medial part was reduced, and its upper pole was laterally displaced. 2) In the posterior view, the left lobe of the liver was separated from the spleen and the distance between the liver and the spleen increased. 3) In the right lateral view, the notch separating the right and the left lobes of the liver was well demarcated. 4) In the left lateral view, the spleen was separated from the liver and the distance between the liver and the spleen increased. The shape of the spleen was also changed. In case of the follow-up study, above changes should make one consider the possibility of the effect of gastric filling.

The authors studied to evaluate the difference of the diagnostic performance between reading from digital image on the video CRT of PACS (Picture Archiving and Communication System) and from analogue image of conventional film mode. We compared interpretative accuracy of above two reading modes by having two observers read a series of liver scintigrams. Images were read once from film and a second time from video CRT of elementary PACS. The concordance rate of interpretation of the two modes was in the range from 61.0% to 93.2%. The diagnostic accuracies of digital image reading and analogue image reading were 72.9% and 74.6% respectively in one observer, and 72.9% and 76.3% in another one. No significant difference in interpretative accuracy could be found between two modes of reading.

Patients with acute pyleonephritis may present with a spectrum of clinical symptoms and signs. There are few noninvasive diagnostic studies, however, to confirm or exclude this diagnosis. To evaluate the clinical utility of $^{99m}Tc-DMSA$ renal scan in diagnosis of acute pyelonephritis, we performed $^{99m}Tc-DMSA$ renal scan in 37 patients suspected with urinary tract infection. Simultaneously, kidney ultrasonography was done in 21 patients diagnosed with acute pyelonephritis, clinically. And we performed the followup scan after treatment in two to six weeks. The results were as follows: 1) $^{99m}Tc-DMSA$ renal scan disclosed single or multiple cortical defects and decreased radiouptake ratio of affected kidney in 23 patients among 25 patients diagnosed with acute pyleonephritis. 2) In the 21 patients with acute pyelonephritis, kidney ultrasonography showed abnormal finding in the 7 patients. And $^{99m}Tc-DMSA$ renal scan disclosed abnormal cortical defects in this 7 patients also. 3) Between the patients with acute pyelonephritis and those with lower urinary tract infection, asymptomatic bacteriuria or pyuria. right-to-left radiouptake ratios (R/L ratio) were significantly different (p < 0.001). 4) In two to six weeks after antibiotic therapy, we performed followup $^{99m}Tc-DMSA$ renal scan for 5 patients among 25 acute pyelonephritis patients. And we have found the improvement of cortical defects and the right-to-left radiouptake ratio. In conclusion, we thought that $^{99m}Tc-DMSA$ renal scan should be useful in diagnosis of acute pyelonephritis and follow-up examination.

Yasculogenic impotence is produced by abnormalities of vascular blood supply or drainage, and is the most common cause of various organic impotences. An increasing awareness of vascular causes of impotence has resulted from development of various diagnostic tests, but precise measurement of penile blood flow is difficult. Radionuclide penogram has been introduced recently to diagnose vasculogenic impotence. Forty-one impotent patients and 12 normal men were studied with radionuclide erection penogram using Tc-99m pertechnetate and an intracavernous injection of papaverine. We defined arteriogenic impotence as arterial index less than 0.66, and venogenic impotence as venous index greater than 0.09. By this criteria, the false positive ratio in normal men was 17%, and the false negative ratio in radically cystectomized patients was 0%. Side effects were small purpura of the penile shaft and dull pain during injection of papaverine. The radionuclide erection penogram was noninvasive and gave a dynamic evaluation of the arterial supply, venous drainage, and blood flow in the corporeal bodies. This method should be considered as a valuable adjunct to evaluate patients with vasculogenic impotence.

Tc-99m-tin colloid distribution in the hip is studied in 76 patients with no hepatic and hip disorder, because knowledge of normal uptake pattern in the hip is important in evaluation of femoral head vasculature after a fracture. The uptake in femoral head is decreased or disappeared with increasing age due to conversion of red marrow to white marrow.

Inflammation scan using radiolabelled leukocytes has high sensitivity and specificity. Several methods for labelling leukocytes have been evaluated using P-32 diisopropyl fluorophosphate (DFP-32), H-3 thymidine, Cr-51 chromate, Ga-67 citrate and Tc-99m-sulfur colloid. In-111-oxine has proved so far to be the most reliable agent for labelling leukocytes. In-111-oxine is, however, expensive, not easily available when needed, and its radiation dose to leukocytes is relatively high. Moreover, resolution of the resultant image is relatively poor. Tc-99m is still the agent of choice because of, as compared with the indium, its favorable physical characteristics, lower cost and availability. Now the technique for labelling the leukocytes with technetium is successfully obtained using the lipophilic HAPAO with higher efficiency for granulocytes than for other cells. With this technique it is possible to label leukocytes in plasma to improve the viability of the leukocytes. Inflammation scan using Tc-99m-HMPAO has been evaluated in several laboratories, and difference in methods for separation and labelling accounts for difference in efficiency, viability and biodistribution of the labelled leukocytes. We performed inflammation scan using leukocytes labelled with Tc-99m-HMPAO in three dogs 24 hours after inoculation of live E. Coli and A. Aureus in their right abdominal wall. We separated mixed leukocytes by simple sedimentation using 6% hetastarch (HES) and labelled the leukocytes with Tc-99m-HMPAO in 20% cell free plama diluted with phosphate buffer solution(Fig. 1). Uptake was high in the liver and spleen but is was minimal in the lungs on whole body scan. Kidneys and intestine showed minimal activity although it was high in the urinary bladder(Fig. 2). Uptake of labelled leukocytes in the inflammation site was do(mite on 2 hour-postinjection scan and abscess was clearly delineated on 24 hour-delayed scan with high target-to-nontarget ratio(Fig. 3, 4). Inflammation scan using mixed leukocytes labelled with Tc-99m-HMPAO is very sensitive and specific in early detection of inflammation.

According to the development of monoclonal antibodies against cyclosporine, it became available to replace the conventional polyclonal antibody method with new monoclonal antibody method to measure the blood level of cyclosporine by radioimmunoassay. We compared the results obtained by the two methods: polyclonal antibody and monoclonal antibody method. The results were obtained as follows: 1) We obtained mean value 137.3 ng/ml and CV 16.1% from plasma sample, and mean values 495.7 ng/ml and 1053.8 ng/ml and CVs 19.3% and 17.4% respectively from whole blood sample by polyclonal antibody method. 2) For the two control groups, 100 ng/ml 400 ng/ml each, we obtained that the CVs were 20.2% and 14.0% respectively from plasma sample, and 11 9% and 13.1% respectively from whole blood sample by monoclonal antibody method. In conclusion, we found that cyclosporine RIA was a relatively reliable method to measure blood or plasma concentration. Especially RIA using monocloanl antibody showed less degree of error in measurement compared to polyclonal antibody method.

Continuous ambulatory peritoneal dialysis (CAPD) is a well established method of treating end stage renal failure, and is commonly used as an alternative to hemodialysis. Several complications have been observed. These include catheter malfunction, abdominal and inguinal hernia, and peritonitis. A relatively frequent complication is swelling of external genitalia, due to bowel fluid passing through a patent processus vaginalis. Special diagnostic procedures are necessary to determine the nature of the abnormality and to guide the surgical correction. We reported two cases of patent processus vaginalis in patient on CAPD proved by radionuclide peritoneal scintiscan using Tc-99 m-tin colloid.