Preoperative Evaluation of Brain Lesion with 201Tl Brain SPECT: Is It Useful to Differentiate Benign and Malignant Lesions? / 대한핵의학회잡지

PURPOSE: Thallim-201 (201Tl) brain SPECT, which can represent cellular activity of brain lesions, may provide more useful information in differentiating between benign and malignant brain lesions more so than CT or MRI, that merely represents anatomic changes or breakdown of blood brain barrier. We used 201Tl brain SPECT prospectively to evaluate the utility of 201Tl-indices as an indicator of benign or malignant lesions. MATERIALS AND METHODS: We studied 28 patients. There were 13 cases of benign lesions (3: nonspecific benign lesion, 3: meningioma, 2: low grade glioma, 1: tuberculoma, central neurocytoma, hemangioblastoma, radiation necrosis, and choroid plexus papilloma) and 15 cases of malignant lesions (6: glioblastoma multiforme, 5: anaplastic glioma, 2: medulloblastoma, 1: metastasis and lymphoma). In all patients, CT and/or MRI were obtained and then 201Tl brain SPECT was obtained with measuring mean 201Tl index and peak 201Tl index. An unpaired t-test was performed to compare the 201Tl-indices and pathologic diagnoses to evaluate the utility of 201Tl-indices as an indicator of benign or malignant lesions. RESULTS: There were no statistically significant difference in 201Tl-indices between benign and malignant brain lesions (P>0.05). CONCLUSION: These results demonstrated that we could not use 201Tl indices on brain SPECT alone as an indicator of benign or malignant brain lesions.

Development of Formulas for the Estimation of Renal Depth and Application in the Measurement of Glomerular Filtration Rate in Koreans / 대한핵의학회잡지

PURPOSE: There is no established formula for estimating renal depths in Korean. As a result, we undertook this study to develop a new formula, and to apply this formula in the calculation of glomerular filtration rate (GFR). MATERIALS AND METHODS: We measured the renal depth (RD) on the abdominal CT obtained in 300 adults (M:F=167:133, mean age 50.9 years) without known renal diseases. The RDs measured by CT were compared with the estimated RDs based on the Tonnesen and Taylor equations. New formulas were derived from the measured RDs in 200 out of 300 patients based on several variables such as sex, age, weight, and height by multiple regression analysis. The RDs estimated from the new formulas were compared with the measured RDs in the remaining 100 patients as a control. In 48 patients who underwent Tc-99m DTPA renal scintigraphy, GFR was measured with three equations (new formula, Tonnesen and Taylor equations), respectively, and compared with each other. RESULTS: The mean values of the RDs measured from CT were 6.9 cm for right kidney of the men (MRK), 6.7 cm for left kidney of the men (MLK), 6.7 cm for right kidney of the women (WRK), and 6.6 cm for left kidney of the women (WLK). The RDs estimated from Tonnesen equation were shorter than the ones measured from CT significantly. The newly derived formulas were 12.813 (weight/height)+0.002 (age)+ 2.264 for MRK, 15.344 (weight/height)+0.011 (age)+0.557 for MLK, 12.936 (weight/height)+ 0.014 (age)+1.462 for WRK and 13.488 (weight/height)+0.019 (age)+0.762 for WLK. The correlation coefficients of the RD measured from CT and estimated from the new formula were 0.529 in MRK, 0.729 in MLK, 0.601 in WRK, and 0.724 in WLK, respectively. The GFRs from the new formula were significantly higher than those from the Tonnesen equation significantly, which was the most similar to normal GFR values. CONCLUSION: We generated new formulas for estimating RD in Korean from the data by CT. By adopting these formulas, we expect that GFR can be measured by the Gates method accurately in Korean.