Ischemic Burden Assessment Using Single Photon Emission Computed Tomography in Single Vessel Chronic Total Occlusion of Coronary Artery

Background and Objectives@#Studies evaluating the nature of ischemic burden of chronic total occlusion (CTO) vessels are still lacking. @*Methods@#A total of 165 patients with single vessel CTO >2.5 mm in an epicardial coronary artery who underwent single photon emission computed tomography (SPECT) were enrolled in the study. Ischemic burden was calculated with the use of semi-quantitative SPECT analysis, and was defined as the summed difference score (SDS) divided by the maximal limit of the score (=SDS/68). @*Results@#The mean age of the participants was 59.5 years and the CTO of the left anterior descending coronary artery (LAD), left circumplex coronary artery (LCX), and right coronary artery (RCA) accounted for 93 (56.4%), 18 (10.9%), and 54 (32.7%) patients, respectively. The median ischemic burden of the total population was 8.8%, and it was highest in the LAD CTO (10.3%) compared with the LCX (5.9%) and RCA CTO (5.9%, p10%) was observed in 66 patients (40.0%), and in 47 patients (50.5%) of the LAD CTO. Ischemic burden was different according to the CTO location only in LAD CTO. The statistically significant predictors for high-ischemic burden were hypertension, baseline ejection fraction >45%, LAD CTO, proximal CTO location, and de novo CTO. Japanese-CTO score and Rentrop scale collateral grade were not associated with high-ischemic burden. @*Conclusions@#Only 40% of patients with single vessel CTO had ischemic burden >10%. For CTO vessels, measurement of ischemic burden using SPECT prior to revascularization may be helpful in identifying beneficial subjects.

Management strategies for congenital isolated hydronephrosis and the natural course of the disease

Congenital isolated hydronephrosis encompasses a spectrum of physiologic states that spontaneously resolve and pathologic obstruction that necessitates surgical intervention. Distinguishing patients whose condition will resolve, those who will require stringent follow-up, and those who will eventually need surgical intervention present a challenge to clinicians, particularly because no unified guidelines for assessment and follow-up have been established. The recognition of the natural course and prognosis of hydronephrosis and a comprehensive understanding of the currently proposed consensus guidelines may aid in multidisciplinary treatment and in providing proper counseling to caregivers. In this review, we aimed to summarize the literature on the grading systems and management strategies for congenital isolated hydronephrosis.

Value of the Filtration Fraction Assessed by Dynamic ⁹⁹mTc-Diethylenetriaminepentaacetic Acid Renal Scintigraphy After Angiotensin-Converting Enzyme Inhibition for the Diagnosis of Renovascular Hypertension / 대한핵의학회잡지

PURPOSE: This study aimed to determine the diagnostic value of the relative filtration fraction (RFF) assessed by dynamic ⁹⁹mTc-diethylenetriaminepentaacetic acid (⁹⁹mTc-DTPA) renal scintigraphy after angiotensin-converting enzyme (ACE) inhibition for renovascular hypertension (RVHT) diagnosis.METHODS: ⁹⁹mTc-DTPA captopril renal scintigraphy performed in adolescents or adults (≥ 10 years) with suspected RVHT was retrospectively reviewed. The RFF of the affected kidney was qualitatively assessed as the relative glomerular filtration rate during the 2 to 3-min period compared with the relative perfusion during the first 60 s (qualitative RFF) and scored from 1 (definitely same) to 5 (definitely decreased). The quantitative RFF of the affected kidney was obtained by dividing the percentage of glomerular filtration rate by the percentage of renal perfusion.RESULTS: Overall, 173 patients (high probability, n = 15; and low probability, n = 158) were included based on conventional captopril renal scintigraphic criteria. An abnormal qualitative RFF was observed in 12 patients with high probability, and the diagnostic sensitivity was 80.0% (95% CI, 51.9–95.7). The RFF was normal in 152 patients with low probability, and the diagnostic specificity was 96.2% (95% CI, 91.9–98.6). The RFF was lower in patients with high probability than in those with low probability (0.79 ± 0.15 vs. 1.02 ± 0.11, P < 0.0001).CONCLUSIONS: The RFF assessed by dynamic ⁹⁹mTc-DTPA renal scintigraphy after ACE inhibition can detect patients with high probability for RVHT. The RFF after ACE inhibition might be a useful diagnostic criterion especially when baseline scintigraphy is not available for evaluating ACE inhibition-induced changes.

Value of the Filtration Fraction Assessed by Dynamic ⁹⁹mTc-Diethylenetriaminepentaacetic Acid Renal Scintigraphy After Angiotensin-Converting Enzyme Inhibition for the Diagnosis of Renovascular Hypertension / 대한핵의학회잡지

PURPOSE@#This study aimed to determine the diagnostic value of the relative filtration fraction (RFF) assessed by dynamic ⁹⁹mTc-diethylenetriaminepentaacetic acid (⁹⁹mTc-DTPA) renal scintigraphy after angiotensin-converting enzyme (ACE) inhibition for renovascular hypertension (RVHT) diagnosis.@*METHODS@#⁹⁹mTc-DTPA captopril renal scintigraphy performed in adolescents or adults (≥ 10 years) with suspected RVHT was retrospectively reviewed. The RFF of the affected kidney was qualitatively assessed as the relative glomerular filtration rate during the 2 to 3-min period compared with the relative perfusion during the first 60 s (qualitative RFF) and scored from 1 (definitely same) to 5 (definitely decreased). The quantitative RFF of the affected kidney was obtained by dividing the percentage of glomerular filtration rate by the percentage of renal perfusion.@*RESULTS@#Overall, 173 patients (high probability, n = 15; and low probability, n = 158) were included based on conventional captopril renal scintigraphic criteria. An abnormal qualitative RFF was observed in 12 patients with high probability, and the diagnostic sensitivity was 80.0% (95% CI, 51.9–95.7). The RFF was normal in 152 patients with low probability, and the diagnostic specificity was 96.2% (95% CI, 91.9–98.6). The RFF was lower in patients with high probability than in those with low probability (0.79 ± 0.15 vs. 1.02 ± 0.11, P < 0.0001).@*CONCLUSIONS@#The RFF assessed by dynamic ⁹⁹mTc-DTPA renal scintigraphy after ACE inhibition can detect patients with high probability for RVHT. The RFF after ACE inhibition might be a useful diagnostic criterion especially when baseline scintigraphy is not available for evaluating ACE inhibition-induced changes.

Impact of Follow-Up Ischemia on Myocardial Perfusion Single-Photon Emission Computed Tomography in Patients with Coronary Artery Disease

PURPOSE: Few studies have reported on predicting prognosis using myocardial perfusion single-photon emission computed tomography (SPECT) during coronary artery disease (CAD) treatment. Therefore, we aimed to assess the clinical implications of myocardial perfusion SPECT during follow-up for CAD treatment. MATERIALS AND METHODS: We enrolled 1153 patients who had abnormal results at index SPECT and underwent follow-up SPECT at intervals ≥6 months. Major adverse cardiac events (MACE) were compared in overall and 346 patient pairs after propensity-score (PS) matching. RESULTS: Abnormal SPECT was associated with a significantly higher risk of MACE in comparison with normal SPECT over the median of 6.3 years (32.3% vs. 19.8%; unadjusted p<0.001). After PS matching, abnormal SPECT posed a higher risk of MACE [32.1% vs. 19.1%; adjusted hazard ratio (HR)=1.73; 95% confidence interval (CI)=1.27–2.34; p<0.001] than normal SPECT. After PS matching, the risk of MACE was still higher in patients with abnormal follow-up SPECT in the revascularization group (30.2% vs. 17.9%; adjusted HR=1.73; 95% CI=1.15–2.59; p=0.008). Low ejection fraction [odds ratio (OR)=5.33; 95% CI=3.39–8.37; p<0.001] and medical treatment (OR=2.68; 95% CI=1.93–3.72; p<0.001) were independent clinical predictors of having an abnormal result on follow-up SPECT. CONCLUSION: Abnormal follow-up SPECT appears to be associated with a high risk of MACE during CAD treatment. Follow-up SPECT may play a potential role in identifying patients at high cardiovascular risk.

Near-infrared Fluorescence Imaging Using a Protease-activatable Nanoprobe in Tumor Detection: Comparison with Narrow-band Imaging

BACKGROUND/AIMS: Advances in endoscopic technology seek to improve the accuracy of neoplastic tumor detection. Recently developed endoscopy devices such as narrow-band imaging (NBI) nevertheless have limitations in morphologic diagnosis. The purpose of this study was to investigate whether a novel imaging technique-near-infrared fluorescence (NIRF) imaging using a protease-activatable nanoprobe-could provide more accurate neoplastic tumor detection, compared to NBI. METHODS: Images of the intestines of Apc(Min/+) mice were obtained by NIRF using a matrix metalloproteinase (MMP)-sensing probe, which was based on a nanoparticle platform. Immediately after imaging, endoscopy with NBI capability was performed on the same excised intestine. Macroscopic and microscopic findings in the intestines were assessed, and MMP expression was analyzed by Western blotting and real-time polymerase chain reaction. RESULTS: Numerous tiny polypoid lesions were present in the intestines of aged Apc(Min/+) mice. These lesions included adenomas, lymphoid follicles, and protruding normal tissues. When using NIRF imaging with an MMP-activatable nanoprobe, adenomatous polyps showed higher fluorescence, compared to lymphoid follicles or adjacent normal tissues. The expression of MMP was higher in the adenomatous tissue than in the other tissues. The sensitivity and specificity for adenoma detection were 88.9% and 82.2%, respectively, when using NIRF imaging with a MMP-nanoprobe, compared to 77.8% and 66.7%, respectively, when using NBI (P<0.05). CONCLUSIONS: Near-infrared fluorescence imaging with a protease-activatable nanoprobe could aid in the differentiation of tumor characteristics. Clinical application of this approach may improve the endoscopic detection of neoplastic tumors.

Assessment of Collagen-Induced Arthritis Using Cyanine 5.5 Conjugated with Hydrophobically Modified Glycol Chitosan Nanoparticles: Correlation with 18F-Fluorodeoxyglucose Positron Emission Tomography Data

OBJECTIVE: To evaluate the potential and correlation between near-infrared fluorescence (NIRF) imaging using cyanine 5.5 conjugated with hydrophobically modified glycol chitosan nanoparticles (HGC-Cy5.5) and 18F-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) imaging of collagen-induced arthritis (CIA). MATERIALS AND METHODS: We used 10 CIA and 3 normal mice. Nine days after the injecting collagen twice, microPET imaging was performed 40 minutes after the intravenous injection of 9.3 MBq 18F-FDG in 200 microL PBS. One day later, NIRF imaging was performed two hours after the intravenous injection of HGC-cy5.5 (5 mg/kg). We assessed the correlation between these two modalities in the knees and ankles of CIA mice. RESULTS: The mean standardized uptake values of 18F-FDG for knees and ankles were 1.68 +/- 0.76 and 0.79 +/- 0.71, respectively, for CIA mice; and 0.57 +/- 0.17 and 0.54 +/- 0.20 respectively for control mice. From the NIRF images, the total photon counts per 30 mm2 for knees and ankles were 2.32 +/- 1.54 x 10(5) and 2.75 +/- 1.51 x 10(5), respectively, for CIA mice, and 1.22 +/- 0.27 x 10(5) and 0.88 +/- 0.24 x 10(5), respectively, for control mice. These two modalities showed a moderate correlation for knees (r = 0.604, p = 0.005) and ankles (r = 0.464, p = 0.039). Moreover, both HGC-Cy5.5 (p = 0.002) and 18F-FDG-PET (p = 0.005) imaging also showed statistically significant differences between CIA and normal mice. CONCLUSION: NIRF imaging using HGC-Cy5.5 was moderately correlated with 18F-FDG-PET imaging in the CIA model. As such, HGC-Cy5.5 imaging can be used for the early detection of rheumatoid arthritis.

Near-Infrared Fluorescence Imaging Using a Protease-Specific Probe for the Detection of Colon Tumors

BACKGROUND/AIMS: Early tumor detection is crucial for the prevention of colon cancer. Near-infrared fluorescence (NIRF) imaging using a target-activatable probe may permit earlier disease detection. Matrix metalloproteinases (MMPs) participate in tumorigenesis and tumor growth. The aim of this study was to determine whether NIRF imaging using an MMP-activatable probe can detect colon tumors at early stages. METHODS: We utilized two murine colon cancer models: a sporadic colon cancer model induced by azoxymethane (AOM), and a colitis-associated cancer model induced by a combination of AOM and dextran sodium sulfate (DSS). Colonic lesions were analyzed by histologic examination, Western blotting, immunohistochemical staining, and NIRF imaging using an MMP-activatable probe. RESULTS: Multiple variable-sized tumors developed in both models and progressed from adenomas to adenocarcinomas over time. At the early stage of the AOM/DSS model, diffuse inflammation was observed within the tumors. MMP expression increased progressively through normal, inflammation, adenoma, and adenocarcionoma stages. NIRF signal intensities were strongly correlated with each tumor stage from adenoma to adenocarcinoma. NIRF imaging also distinguished tumors from inflamed mucosa. CONCLUSIONS: NIRF imaging using a protease-activatable probe may be a useful tool for early tumor detection. This approach could translate to improve the endoscopic detection of colon tumors, especially in patients with inflammatory bowel disease.

Brown Tumor Shown Flare Phenomenon On Bone Scan After Parathyroidectomy / 핵의학분자영상

Brown tumor is the benign bone lesion consists of woven bone and fibrous tissue without matrix, which develop due to chronic excessive osteoclastic activity such as hyperparathyroidism. Usually they appear with normal uptake or occasionally focally increased uptake on bone scan. We present a case with brown tumor shown more increased uptake and more number of lesions on bone scan after parathyroidectomy, and lesser increased uptake on serial bone scans without any other treatment through several months. This finding is thought to be similar to 'flare phenomenon' which is occasionally seen after treatment of metastatic bone lesions of malignant cancer, and may represent curative process of brown tumor with rapid normal bone formation.

Pilot Study for the Prediction of Response to Radiotherapy Using (18)FFluorothymidine PET in Nasopharyngeal Cancer: Comparison with (18)FFDG PET / 핵의학분자영상

PURPOSE: This study was performed to know whether [(18)F]Fluorothymidine (FLT) positron emission tomography (PET) can be used to monitor early response to radiotherapy in comparison with [(18)F]Fluorodeoxyglucose (FDG) PET, and to establish the optimal imaging time for prediction of therapy response. MATERIALS AND METHODS: Two patients with nasopharyngeal cancer underwent serial FLT PET and FDG PET before and during radiotherapy. Three on-treatment FLT and FDG PET scans were performed on 1 week, 2 weeks and 3 weeks (at each time of 10 Gy, 20 Gy and 30 Gy delivered). The peak standardized uptake values (SUV(peak)) of primary tumors were measured on FLT and FDG PET. Then, percent changes of SUV(peak) after therapy were calculated. RESULTS: In two patients, baseline values of SUV(peak) on FDT PET were higher than those on FLT PET (FLT vs FDG; 3.7 vs 5.0, and 5.7 vs 15.0). In patient 1, FLT SUV(peak) showed 78%, 78% and 84% of decrease on 1 week, 2 and 3 weeks after treatment, whereas FDG SUV(peak) showed 18%, 52% and 66% of decrease, respectively. In patient 2, FLT SUV(peak) showed 75%, 75% and 68% of decrease, whereas FDG SUV(peak) showed 51%, 49% and 58% of decrease, respectively. Both patients reached to complete remission after radiotherapy. CONCLUSION: After radiotherapy, the decrease of FLT tumor uptake preceded the decrease of FDG tumor uptake in patients with nasopharyngeal cancer, and 1 week after therapy may be appropriate time for the assessment of early response. FLT PET might be more useful than FDG PET for monitoring early response to radiotherapy.

Molecular Imaging in Neurodegenerative Diseases

Neurodegenerative diseases are highly morbid and widespread in the nation with aged population. Since these are progressive and irreversible diseases, early detection and differentiation of the disease are important for possible therapeutic intervention. Alzheimer's disease and Parkinson's disease are the most frequent and costly devastating neurodegenerative diseases. Recent advances of molecular imaging, especially positron emission tomography (PET) technique, allows non-invasive evaluation of not only regional cerebral metabolism or perfusion, but also the change of neurotransmission and presence of abnormal protein such as beta amyloid. In Parkinsonism, dopamine transporter and vesicular monoamine transporter imaging are useful in the diagnosis and evaluation of the disease progression since these provide information about the integrity of presynaptic striatal dopaminergic neurons. In Alzheimer s disease, beta-amyloid imaging can assess the amyloid deposition. It improves early diagnosis and possibility of a presymptomatic diagnostic biomarker; improves understanding of the natural history of amyloid deposition; and has the capability to directly measure the effects of newly developed anti-amyloid therapies. Cholinergic and microglial imaging can be also useful in the early diagnosis of dementia and improves understanding of insights into pathophysiology of neurodegenerative diseases. Therefore, the ability of molecular imaging to identify and quantify cerebral pathology has significant implications for early detection, differential diagnosis, and therapeutic monitoring in neurodegenerative diseases.

Molecular Imaging in Neurodegenerative Diseases

Neurodegenerative diseases are highly morbid and widespread in the nation with aged population. Since these are progressive and irreversible diseases, early detection and differentiation of the disease are important for possible therapeutic intervention. Alzheimer's disease and Parkinson's disease are the most frequent and costly devastating neurodegenerative diseases. Recent advances of molecular imaging, especially positron emission tomography (PET) technique, allows non-invasive evaluation of not only regional cerebral metabolism or perfusion, but also the change of neurotransmission and presence of abnormal protein such as beta amyloid. In Parkinsonism, dopamine transporter and vesicular monoamine transporter imaging are useful in the diagnosis and evaluation of the disease progression since these provide information about the integrity of presynaptic striatal dopaminergic neurons. In Alzheimer s disease, beta-amyloid imaging can assess the amyloid deposition. It improves early diagnosis and possibility of a presymptomatic diagnostic biomarker; improves understanding of the natural history of amyloid deposition; and has the capability to directly measure the effects of newly developed anti-amyloid therapies. Cholinergic and microglial imaging can be also useful in the early diagnosis of dementia and improves understanding of insights into pathophysiology of neurodegenerative diseases. Therefore, the ability of molecular imaging to identify and quantify cerebral pathology has significant implications for early detection, differential diagnosis, and therapeutic monitoring in neurodegenerative diseases.

Clinical Significance of Incidental Asymmetric Palatine Tonsillar Uptake on (18)F-FDG PET/CT / 핵의학분자영상

PURPOSE: The aim of this study was to determine the incidence and malignant rate of incidental asymmetric palatine tonsillar uptake (ATU) on (18)F-FDG PET/CT in various clinical indications and to evaluate the clinical and PET/CT findings suggesting malignancy. MATERIALS AND METHODS: We retrospectively reviewed a total of 2,901 patients (58.4+/-12.3 yrs, range 20~88 yrs, M:F=1,841:1,060) who underwent (18)F-FDG PET/CT during an 1-year period with various indications except primary tonsillar cancer and lymphoma evaluation. On (18)F-FDG PET/CT, metabolic abnormality of the palatine tonsil and cervical lymph node were visually assessed. ATU was defined as increased palatine tonsillar uptake with diffuse, focal, or irregular pattern compared to contralateral side. The incidence and malignant ratio of ATU were evaluated according to clinical and PET/CT findings. RESULTS: Of 2,901 cases, 290 (10.0%) showed ATU. The incidence of ATU showed seasonal variation and was high in the winter (12.1%). Of 209 cases with ATU confirmed pathologically and/or clinically, five (2.4%) were malignant lesions. ATU with irregular uptake pattern (2/2) and in cases referred for cervical lymph node metastasis of unknown origin (3/5) were frequently associated with malignant lesion (p<0.05). CONCLUSION: ATU was not infrequently observed on (18)F-FDG PET/CT, and the malignant risk of ATU was low. However, ATU with cervical lymph node metastasis or with irregular pattern on PET/CT would be further evaluated by the histopathologic examination.

The Serial Change of Cerebral Hemodynamics by Vascular Territory after Extracranial-Intracranial Bypass Surgery in Patients with Atherosclerosis of Cerebral Arteries / 핵의학분자영상

PURPOSE: To assess the effect of extracranial-intracranial (EC-IC) bypass surgery on hemodynamic improvement, we evaluated serial regional cerebral hemodynamic change of the middle cerebral artery (MCA) in symptomatic patients with atherosclerotic occlusion of the internal carotid artery (ICA) or MCA using (99m)Tc-ECD acetazolamide stress brain perfusion SPECT (Acetazolamide SPECT). MATERIAL AND METHODS: The patients who had suffered a recent stroke with atherosclerotic ICA or MCA occlusion underwent EC-IC bypass surgery and Acetazolamide SPECT at 1 week before and three to six months after surgery. For image analysis, attenuation corrected images were spatially normalized to SPECT templates with SPM2. Anatomical automated labeling was applied to calculate mean counts of each Volume-Of-Interest (VOI). Seven VOIs of bilateral frontal, parietal, temporal regions of the MCA territory and the ipsilateral cerebellum were defined. Using mean counts of 7 VOIs, cerebral perfusion index and perfusion reserve index were calculated. RESULTS: Seventeen patients (M:F=12:5, mean age: 53+/-2yr) were finally included in the analysis. The cerebral blood flow of the parietal region increased at 1 week (p=0.003) and decreased to the preoperative level at 3-6 months (p=0.003). The cerebrovascular reserve of the frontal and parietal regions increased significantly at 1 week after surgery (p<0.01) and improved further at 3-6 months. CONCLUSION: Cerebrovascular reserve of the MCA territory was significantly improved at early postoperative period after EC-IC bypass and kept improved state during long-term follow-up, although cerebral blood flow did not significantly improved. Therefore, cerebrovascular reserve may be a good indicator of postoperative hemodynamic improvement resulted from bypass effect.

A Pilot Study for the Feasibility of F-18 FLT-PET in Locally Advanced Breast Cancer: Comparison with F-18 FDG-PET / 핵의학분자영상

PURPOSE: The aim of this study was to investigate the feasibility of 3'-[F-18]fluoro-3'-deoxythymidine positron emission tomography(FLT-PET) for the detection of locally advanced breast cancer and to compare the degree of FLT and 2'-deoxy-2'-[F-18]fluoro-d-glucose(FDG) uptake in primary tumor, lymph nodes and other normal organs. MATERIAL AND METHODS: The study subjects consisted of 22 female patients (mean age; 42+/-6 years) with biopsy-confirmed infiltrating ductal carcinoma between Aug 2005 and Nov 2006. We perfomed conventional imaging workup, FDG-PET and FLT PET/CT. Average tumor size measured by MRI was 7.2+/-3.4 cm. With visual analysis, Tumor and Lymph node uptakes of FLT and FDG were determined by calculation of standardized uptake value (SUV) and tumor to background (TB) ratio. We compared FLT tumor uptake with FDG tumor uptake. We also investigated the correlation between FLT tumor uptake and FDG tumor uptake and the concordant rate with lymph node uptakes of FLT and FDG. FLT and FDG uptakes of bone marrow and liver were measured to compare the biodistribution of each other. RESULTS: All tumor lesions were visually detected in both FLT-PET and FDG-PET. There was no significant correlation between maximal tumor size by MRI and SUVmax of FLT-PET or FDG-PET (p>0.05). SUVmax and SUV75 (average SUV within volume of interest using 75% isocontour) of FLT-PET were significantly lower than those of FDG-PET in primary tumor (SUVmax; 6.3+/-5.2 vs 8.3+/-4.9, p=0.02 / SUV75; 5.3+/-4.3 vs 6.9+/-4.2, p=0.02). There is significant moderate correlation between uptake of FLT and FDG in primary tumor (SUVmax; rho=0.450, p=0.04 / SUV75; rho=0.472, p=0.03). But, TB ratio of FLT-PET was higher than that of FDG-PET(11.7+/-7.7 vs 6.3+/-3.8, p=0.001). The concordant rate between FLT and FDG uptake of lymph node was reasonably good (33/34). The FLT SUVs of liver and bone marrow were 4.2+/-1.2 and 8.3+/-4.9. The FDG SUVs of liver and bone marrow were 1.8+/-0.4 and 1.6+/-0.4. CONCLUSION: The uptakes of FLT were lower than those of FDG, but all patients of this study revealed good FLT uptakes of tumor and lymph node. Because FLT-PET revealed high TB ratio and concordant rate with lymph node uptakes of FDG-PET, FLT-PET could be a useful diagnostic tool in locally advanced breast cancer. But, physiological uptake and individual variation of FLT in bone marrow and liver will limit the diagnosis of bone and liver metastases.

1 year follow-up results of prenatally diagnosed unilateral hydronephrosis according to renal sonographic findings at 1 month of age / 소아과

PURPOSE: The natural courses of prenatally diagnosed hydronephrosis(HN) are diverse. Our purpose was to determine if the findings of renal ultrasonography(USG) in patients with prenatal HN at 1 month of age can predict the 1 year follow-up results and determine the guideline of follow-up study. METHODS: Among 462 hydronephrotic patients registered between 1996 and 2004, 153 unilateral hydronephrotic renal units were enrolled in this study, bilateral HN, vesicoureteral reflux and other associated anomaly were excluded. These were classified into four groups respectively, according to anterior posterior pelvic diameter(APPD) or Society for Fetal Urology(SFU) grading by USG findings at 1 month after birth. Renal USG and Tc(99m)-mercaptoacetyl triglycerine(MAG3) scan were done according to a set protocol. RESULTS: Most cases improved or remained stationary. No one underwent an operation SFU grade 1,2 groups and only one case of SFU grade 3 group was operated. Thirty two cases(64 percent) were operated on among the 50 cases of SFU grade 4 group. 0/2(0 percent), 5/11(45.5 percent), 11/17(64.7 percent) and 16/20(80 percent) were operated on in each group with APPD 30 mm, and the operation risk is higher as the APPD is increased. CONCLUSION: In group with SFU grade below 3 and APPD below 10 mm, we can delay the follow-up study beyond existing set protocol. Operations are recommended immediately if diuretic renogram show the obstructive pattern or decreased renal function in SFU grade 4 group with APPD over 10 mm.

Accuracy of Ventricular Volume and Ejection Fraction Measured by Gated Tl-201 Perfusion Single Photon Emission Tomography / 대한핵의학회잡지

Electrocardiogram-gated single photon emission computed tomography (SPECT) provides valuable information in the assessment of both myocardial perfusion and ventricular function. Tl-201 is a suboptimal isotope for gating. Tl-201 images are more blurred compared with Tc-99m tracers due to the increased amount of scattered photons and use of a smooth filter. The average myocardial count densities are approximately one-half those of conventional technetium tracers. However, Tl-201 is still widely used because of its well-established utility for assessing myocardial perfusion, viability and risk stratification. Gated SPECT with Tl-201 enables us to assess both post-stress and rest left ventricular volume and function. Previous studies with gated Tl-201 SPECT measurements of ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV) have shown high correlation with first-pass radionuclide angiography, gated blood pool scan, Tc-99m-MIBI gated SPECT, contrast ventriculography, echocardiography, and 3-dimensional magnetic resonance imaging. However, problems related to these studies include few agreement data of EDV and ESV, use of a reference method that is likely to have the same systemic errors (gated Tc-99m-MIBI SPECT), and other technical factors related to the count density of gated SPECT. With optimization of gated imaging protocols and more validation studies, gated Tl-201 SPECT would be an accurate method to provide perfusion and function information in patients with coronary artery disease.

Prediction of Prognosis to Concurrent Chemo-Radiotherapy by Standardized Uptake Value of 2-18F Fluoro-2-Deoxy-D-Glucose for Nasopharyngeal Carcinomas / 대한방사선종양학회지

PURPOSE: To prospectively evaluate the use of positron emission tomography with the glucose analog fluorodeoxyglucose (FDG-PET) to predict disease-free survival (DFS) after concurrent chemo-radiotherapy (CCRT) in patients with non-disseminated nasopharyngeal carcinoma (NPC). MATERIASL AND METHODS: We studied 41 patients with non-disseminated NPC scheduled to undergo platinum- based CCRT were eligible for this study. Patients were studied by FDG-PET prior to the CCRT. FDG uptake of tumors were measured with the maximal standardized uptake value (SUV). RESULTS: Complete response rate was 100%. In ten patients who presented with any component of treatment failure, the median SUVmax was 8.55 (range: 2.49~14.81) in any component of failure and the median SUVmax was 6.48 (range: 2.31~26.07) in the remaining patients without any such failure. Patients having tumors with high FDG uptake had a significantly lower 3-year DFS (51% v 91%, P=0.0070) compared with patients having low uptake tumors. CONCLUSION: FDG uptake, as measured by the SUV, has potential value in predicting DFS in NPC treated by CCRT. High FDG uptake may be a useful parameter for identifying patients requiring more aggressive treatment approaches.

Terminal QRS Complex Distortion on the Admission Electrocardiogram in Anterior Acute Myocardial Infarction and Association with Residual Flow and Infarct Size after Primary Angioplasty

BACKGROUND: Terminal QRS complex distortion on admission is a simple and reliable predictor of infarct size in patients with acute myocardial infarction (AMI). It is uncertain, however, whether this reflects reduced myocardial perfusion of the infarct area and a larger area of the myocardium at risk. This study was conducted to investigate whether terminal QRS distortion complex on admission is a reliable predictor of reduced residual flow and a larger area of the myocardium at risk compared to patients who are admitted without a terminal QRS distortion. METHODS: We evaluated the relationship between terminal QRS complex distortion and residual flow to the infarct zone and risk area in 46 anterior AMI patients undergoing primary angioplasty. 99mTc-sestamibi imaging was performed at baseline and 5-9 days after angioplasty. The study population was divided into those with (Group I, n=16) and without (Group II, n=30) terminal QRS complex distortion. RESULTS: Baseline characteristics were similar between the two groups. The area of the myocardium at risk was higher in Group I (59.9 +/- 15.3%) than in Group II (48.6 +/- 13.7%, p< 0.05; mean+SD) while the nadir measurement of the residual flow was lower in Group I (0.10 +/- 0.07) than in Group II (0.16 +/- 0.09, p< 0.05). Although the final infarct size was significantly higher in Group I (40.8 +/- 17.2%) than in Group II (27.1 +/- 18.1%, p< 0.05), the myocardial salvage index did not differ significantly between the two groups. CONCLUSION: Terminal QRS complex distortion seems to be associated with less residual flow to the infarct zone, a larger risk area and greater infarct size in patients with anterior AMI.

Comparison of 18F FDG-PET and CT/MRI for the Diagnosis of Cervical Lymph Node Metastasis in Head and Neck Cancer: A Level-by-Level Based Study / 대한핵의학회잡지

PURPOSE: Cervical lymph node metastasis is the most important factor of the prognosis and therapeutic planning in head and neck cancer. With increasing interest of minimally invasive neck surgery, more accurate preoperative assessment of cervical lymph node becomes more essential. We evaluated the diagnostic accuracy of 18F FDG-PET in the assessment of lymph node metastasis in patients with primary head and neck cancer and compared the results with those of CT/MRI. MATERIALS AND METHODS: Thirty-two patients (M/F=27/5, 56 +/- 10yr) with biopsy proven head and neck cancer (16 supraglottic cancer, 9 tongue cancer, 7 others) underwent FDG-PET and CT/MRI (25/7) within 1 month before neck dissection. Based on lymph node level, the diagnostic sensitivity and specificity of FDG PET and CT/MRI for the metastasis of cervical lymph node were compared. RESULTS: Of 153 lymph node levels dissected in 32 patients, 32 lymph node levels of 19 patients were positive for metastasis by histopatholologic examination. The overall sensitivity and specificity of FDG-PET were 88% (28/32) and 93% (113/121), whereas those of CT/MRI were 56% (18/32) (p=0.002) and 92% (112/121), respectively. The diagnostic sensitivity and specificity of FDG-PET were different according to location of lymph node levels, and those of ipsilateral level II were lower than those of other levels. CONCLUSION: FDG-PET is more sensitive in detecting metastatic cervical lymph node in head and neck cancer than CT/MRI. FDG-PET might be useful in guiding the extent of neck dissection.