Primary Sternal Osteomyelitis caused by Staphylococcus aureus in an Immunocompetent Adult / 감염과화학요법

Primary sternal osteomyelitis (PSO) is a rare condition that may develop without any contiguous focus of infection. Due to the rarity of the disease, early diagnosis and appropriate treatment are often delayed. Herein, we describe a patient with PSO caused by Staphylococcus aureus that presented with chest pain and fever. The patient had no predisposing factors for sternal osteomyelitis. The chest pain was thought to be non-cardiogenic, as electrocardiography and cardiac enzyme did not reveal ischemic changes when he visited the emergency room. After blood culture revealed the presence of S. aureus, every effort was made to identify the primary focus of infection. Bone scan and magnetic resonance imaging revealed osteomyelitis with soft tissue inflammation around the sternum. After 8 weeks of antibiotics treatment, the patient recovered without any complications.

Comparison between FDG Uptake and Clinicopathologic and Immunohistochemical Parameters in Pre-operative PET/CT Scan of Primary Gastric Carcinoma / 핵의학분자영상

PURPOSE: The purpose of this study was to find out what clinicopathologic or immunohistochemical parameter that may affect FDG uptake of primary tumor in PET/CT scan of the gastric carcinoma patient. MATERIALS AND METHODS: Eighty-nine patients with stomach cancer who underwent pre-operative FDG PET/CT scans were included. In cases with perceptible FDG uptake in primary tumor, the maximum standardized uptake value (SUVmax) was calculated. The clinicopathologic results such as depth of invasion (T stage), tumor size, lymph node metastasis, tumor differentiation and Lauren's classification and immunohistochemical markers such as Ki-67 index, expression of p53, EGFR, Cathepsin D, c-erb-B2 and COX-2 were reviewed. RESULTS: Nineteen out of 89 gastric carcinomas showed imperceptible FDG uptake on PET/CT images. In cases with perceptible FDG uptake in primary tumor, SUVmax was significantly higher in T2, T3 and T4 tumors than T1 tumors (5.8+/-3.1 vs. 3.7+/-2.1, p=0.002). SUVmax of large tumors (above or equal to 3 cm) was also significantly higher than SUVmax of small ones (less than 3 cm) (5.7+/-3.2 vs. 3.7+/-2.0, p=0.002). The intestinal types of gastric carcinomas according to Lauren showed higher FDG uptake compared to the non-intestinal types (5.4+/-2.8 vs. 3.7+/-1.3, p=0.003). SUVmax between p53 positive group and negative group was significantly different (6.0+/-2.8 vs. 4.4+/-3.0, p=0.035). No significant difference was found in presence of LN metastasis, tumor differentiation, Ki-67 index, and expression of EGFR, Cathepsin D, c-erb-B2 and COX-2. CONCLUSION: T stage of gastric carcinoma influenced the detectability of gastric cancer on FDG PET/CT scan. When gastric carcinoma was perceptible on PET/CT scan, T stage, size of primary tumor, Lauren's classification and p53 expression were related to degree of FDG uptake in primary tumor.

Comparison of FDG Uptake with Pathological Parameters in the Well-differentiated Thyroid Cancer / 핵의학분자영상

PURPOSE: Differentiated thyroid cancer (DTC) has variable degree of F-18 FDG avidity. The purpose of this study was to evaluate the relationship between F-18 FDG uptake and pathological or immunohistochemical features of DTC. MATERIALS AND METHODS: DTC patients who underwent both pre-operative F-18 FDG PET/CT scan and surgery were included in the study. Maximum standardized uptake values (SUVmax) of primary tumor were calculated. If the primary tumor showed no perceptibly increased F-18 FDG uptake, region of interest was drawn based on finding of CT portion of the PET/CT images. Pathological and immunohistochemical markers such as presence of lymph node (LN) metastasis and underlying thyroiditis, tumor size, Ki-67 labeling index, expressions of EGFR, COX-2, and Galectin-3 were evaluated. RESULTS: Total of 106 patients was included (102 papillary carcinomas, 4 follicular carcinomas). The mean SUVmax of the large tumors (above 1 cm) was significantly higher than the mean SUVmax of small (equal to or less than 1 cm) ones (7.8+/-8.5 vs. 3.6+/-3.1, p=0.004). No significant difference in F-18 FDG uptake was found according to the presence or absence of LN metastasis and underlying thyroiditis, or the degree of Ki-67 labeling index, expression of EGFR, COX-2 and Galectin-3. CONCLUSION: In conclusion, the degree of F-18 FDG uptake in DTC was associated with the size of primary tumor. But there seem to be no relationship between F-18 FDG uptake of DTC and expression of Ki-67, EGFR, COX-2 and Galectin-3.

A Case of Patella Metastasis of Papillary Thyroid Carcinoma / 핵의학분자영상

A 73-year-old man presented with a chief complaint of progressive left knee pain for two months. He had a history of total thyroidectomy and central lymph node dissection due to papillary thyroid carcinoma three months ago. MRI images revealed a solid mass in the left patella. A solid mass demonstrated low signal on T1 weighed image, and high signal on T2 weighed image. And whole body bone scan showed focal photon defect in same lesion of left patella. The histologic result of left knee lesion was adenocarcinoma, consistent with metastatic papillary thyroid carcinoma. Although patellar metastasis of papillary thyroid carcinoma is very rare, when knee pain and radiologic abnormality are noted, differential diagnosis of metastasis is necessary.

Comparison between FDG Uptake and Pathologic or Immunohistochemical Parametersin Pre-operative PET/CT Scan of Patient with Primary Colorectal Cancer / 핵의학분자영상

PURPOSE: To evaluate the relationship between F-18 FDG uptake of tumor in PET/CT scan and pathological or immunohistochemial parameters of colorectal cancer. MATERIALS AND METHODS: 147 colorectal cancer patients who underwent both pre-operative F-18 FDG PET/CT scan and surgery were included. In cases with perceptible FDG uptake in primary tumor, the maximum standardized uptake value (SUVmax) was calculated. The pathologic results such as site, size, depth of invasion (T stage), growth pattern, differentiation of primary tumor, lymph node metastasis and Dukes-Astler & Coller stage and immunohistochemical markers such as expression of EGFR, MLH1, MSH2 and Ki-67 index were reviewed. RESULTS: 146 out of 147 PET/CT scans with colorectal cancer showed perceptible focal FDG uptake. SUVmax showed mild positive linear correlation with size of primary tumor (r=0.277, p=0.001) and Ki-67 index (r=0.226, p=0.019). No significant difference in F-18 FDG uptake was found according to site, depth of invasion (T stage), growth pattern, differentiation of primary tumor, presence of lymph node metastasis, Dukes-Astler & Coller stage and expression of EGFR. CONCLUSION: The degree of F-18 FDG uptake in colorectal cancer was associated with the size and the degree of Ki-67 index of primary tumor. It could be thought that FDG uptake of primary tumor has a correlation with macroscopic and microscopic tumor growth.

Effect of Repetitive Transcranial Magnetic Stimulation in Drug Resistant Depressed Patients / 핵의학분자영상

PURPOSE: Repetitive transcranial magnetic stimulation (rTMS) has recently been clinically applied in the treatment of drug resistant depressed patients. There are mixed findings about the efficacy of rTMS on depression. Furthermore, the influence of rTMS on the physiology of the brain is not clear. We prospectively evaluated changes of regional cerebral blood flow (rCBF) between pre- and post-rTMS treatment in patients with drug resistant depression. MATERIALS AND METHODS: Twelve patients with drug-resistant depression (7 male, 5 female; age range: 19~52 years; mean age: 29.3+/-9.3 years) were given rTMS on right prefrontal lobe with low frequency (1 Hz) and on left prefrontal lobe with high frequency (20 Hz), with 20-minute-duration each day for 3 weeks. Tc-99m ECD brain perfusion SPECT was obtained before and after rTMS treatment. The changes of cerebral perfusion were analyzed using statistical parametric mapping (SPM; t=3.14, uncorrected p<0.01, voxel=100). RESULTS: Following areas showed significant increase in rCBF after 3 weeks rTMS treatment: the cingulate gyrus, fusiform gyrus of right temporal lobe, precuneus, and left lateral globus pallidus. Significant decrement was noted in: the precental and middle frontal gyrus of right frontal lobe, and fusiform gyrus of left occipital lobe. CONCLUSION: Low-frequency rTMS on the right prefrontal cortex and high-frequency rTMS on the left prefrontal cortex for 3 weeks as an add-on regimen have increased and decreased rCBF in the specific brain regions in drug-resistant depressed patients. Further analyses correlating clinical characteristics and treatment paradigm with functional imaging data may be helpful in clarifying the pathophysiology of drug-resistant depressed patients.

Brain Abscess Uptake at Tl-201 Brain SPECT / 핵의학분자영상

A 22-year-old woman with a history of acute lymphoblastic leukemia was hospitalized for headache and vomiting. CT scan showed a well-defined, ring like enhancing mass in the left frontal lobe with surrounding edema and midline shift. Magnetic resonance imaging demonstrated a round homogeneous mass with a ring of enhancement in the left frontal lobe. Tl-201 brain SPECT showed increased focal uptake coinciding with the CT and MRI abnormality. Aspiration of the lesion performed through a burr hole yielded many neutrophils, a few lymphocytes and histiocytes with some strands of filamentous microorganism-like material. Modified AFB stained negative for norcardia. Gram stain showed a few white blood cells and no microorganism. Antibiotics were started and produced a good clinical response. After one month, CT scan showed markedly reduction in size and extent was observed.

Assessment of Cerebrovascular Reserve before and after STA-MCA Bypass Surgery by SPECT and SPM Analysis

OBJECTIVE: The purpose of this study was to objectively assess the efficacy of superficial temporal artery to middle cerebral artery (STA-MCA) bypass surgery using Technetium (Tc)-99m-ethyl cysteinate dimer (ECD) single photon emission computed tomography (SPECT) in patients who underwent STA-MCA bypass surgery. MATERIALS AND METHODS: Brain perfusion SPECT images obtained at baseline and after the administration of acetazolamide were reconstructed using statistical parametric mapping in 23 patients, both before and after STA-MCA bypass surgery. The clinical outcomes of the surgery were also recorded and compared with the hemodynamic changes. A voxel with an uncorrected p-value of less than 0.001 was considered to be statistically significant. RESULTS: SPECT images of the territory supplied by the bypass graft showed an increase in both cerebrovascular flow and reserve at baseline, and the increase was significantly higher following the administration of acetazolamide. All patients showed improvement of clinical symptoms and increased blood flow to the left temporal, parietal, and frontal cortices as well as the thalamus. CONCLUSION: Brain SPECT effectively and objectively demonstrated the improved outcomes of STA-MCA bypass surgery, and thus may be used in postoperative analyses.

Determination of Appropriate Sampling Frequency and Time of Multiple Blood Sampling Dual Exponential Method with 99mTc-DTPA for Calculating GFR / 핵의학분자영상

PURPOSE: To determine appropriate sampling frequency and time of multiple blood sampling dual exponential method with 99mTc-DTPA for calculating glomerular filtration rate (GFR). MATERIALS AND METHODS: Thirty four patients were included in this study. Three mCi of 99mTc-DTPA was intravenously injected and blood sampling at 9 different times, 5ml each, were done. Using the radioactivity of serum, measured by gamma counter, the GFR was calculated using dual exponential method and corrected with the body surface area. Using spontaneously chosen 2 data points of serum radioactivity, 15 collections of 2-sample GFR were calculated. And 10 collections of 3-sample GFR and 12 collections of 4-sample GFR were also calculated. Using the 9-sample GFR as a reference value, degree of agreement was analyzed with Kendall's tau correlation coefficients, mean difference and standard deviation. RESULTS: Although some of the 2-sample GFR showed high correlation coefficient, over or underestimation had evolved as the renal function change. The 10-120-240 min 3-sample GFR showed a high correlation coefficient (tau=0.93), minimal difference (Mean+/-SD=-1.784+/-3.972), and no over or underestimation as the renal function changed. The 4-sample GFR showed no better accuracy than the 3-sample GFR. CONCLUSIONS: In the wide spectrum of renal function, the 10-120-240 min 3-sample GFR could be the best choice for estimating the patients' renal function.

Incidental Visualization of Hepatic Hemangioma by Tc-99m-HDP Bone Scan / 대한핵의학회잡지

Hepatic hemangioma is the most common benign liver tumor and must be considered in the differential diagnosis of other space occupying hepatic masses. A 54-year-old man was referred to evaluate bone metastases of lung adenocarcinoma. In our case, we thought that a focal hepatic uptake in the bone scan was a metastatic lesion, because of underlying lung adenocarcinoma. However, the findings of abdominal CT and Tc-99m RBC scan results were deemed to be characteristic of hepatic hemangioma. The biopsy of the lesion was not performed.

Analysis of SPECT in Two Sub-types of Subcortical Ischemic Vascular Dementia

BACKGROUND: The brain imaging criteria for subcortical ischemic vascular dementia (SIVD), as proposed by Eurkinjuntti, incorporates the two familiar entities, "the lacunar state" and "Binswanger's disease". However, it has not been proven whether these two subtypes of SIVD have common pathophysiological features. This study investigated the changes of the regional cerebral blood flow (rCBF) in the two subsets of SIVD. METHODS: 12 SIVD patients with predominant white matter lesions, 13 patients with predominant multiple lacunar infarctions and 17 controls were evaluated. The general cognitive function and the severity of dementia were measured by using the K-MMSE and the clinical dementia rating scale. The patients simultaneously met both the NINDS-AIREN criteria for probable or possible vascular dementia (VaD) and the Eurkinjuntti's brain imaging criteria for SIVD. 99mTc-ethyl cysteinate dimmer (ECD)-SPECT was performed to measure the rCBF, and statistical parametric mapping (SPM) was applied to the objective analysis of the SPECT data. RESULTS: SPM analysis of the SPECT images revealed that decreased rCBF in the bilateral thalami, anterior cingulated gyri, superior temporal gyri, caudate heads and left parahippocampal gyrus was significant in the patients with SVaD compared to the controls (uncorrected P=0.001). This pattern of rCBF reduction was the same in both the SIVD patients with predominant white matter lesions and with predominant lacunar infarctions. CONCLUSIONS: Our study suggests that the two subsets of SIVD proposed by Eurkinjuntti may have a common functional abnormality, and the Eurkinjuntti's criteria offers a solution for researchers to identify the more homogeneous group of VaD patients.

Usefulness of 18F-FDG PET/CT in the Diagnosis of Cervical Lymph Node Metastases of Head and Neck Cancer / 대한핵의학회잡지

PURPOSE: This study evaluated the diagnostic value of 18F-FDG PET/CT in detecting cervical lymph node metastases in head and neck cancer patients. MATERIALS AND METHODS: The patients were divided into two groups, 46 patients underwent PET/CT scan for initial staging before surgery, and 20 patients for restaging of recurrence after primary treatment. Increased FDG uptakes in cervical lymph nodes were evaluated retrospectively and correlated with the histopathologic results. RESULTS: In the initial staging group, 21 lymph nodes were detected by PET/CT in 15 patients. 20 lymph nodes were confirmed as metastases with a mean peak SUV of 5.84, and the remaining one lymph node was an inflammatory lesion, with a peak SUV of 2.75. Seven metastatic lymph nodes were reported only by histopathology. The sensitivity, specificity, positive predictive value and negative predictive value were 74.0%, 99.6%, 95.2% and 97.3%, respectively. In the recurrence group, 11 lymph nodes were detected in 9 patients, and 8 nodes were true positive, with a mean peak SUV of 5.65. The other three were inflammatous lymph nodes, and the peak SUVs were 2.16, 2.94 and 3.53. One false negative lymph node was reported. The sensitivity, specificity, positive predictive value and negative predictive value were 88.8%, 97.7%, 72.7% and 92.9%, respectively. CONCLUSIONS: FDG-PET/CT shows higher positive predictive value in the initial staging group, and better sensitivity in the recurrence group. Therefore PET/CT could be useful for both initial staging and restaging of recurrent cervical lymph node metastases.

Changes of Regional Cerebral Blood Flow in Left Anterior Thalamic Infarction: Analysis of 99mTc-Ethyl Cysteinate Dimer (ECD) SPECT by using Statistical Parametric Mapping

BACKGROUND: The thalamus has multiple connections with areas of the cerebral cortex involved in arousal and cognition. Thalamic damage has been reported to be associated with variable neuropsychological dysfunctions and dementia. This study investigates the changes of regional cerebral blood flow (rCBF) by using SPM analysis of 99mTc-ECD SPECT and examining the neuropsychological abnormalities of 4 patients with anterior thalamic infarctions. METHODS: Four patients with left anterior thalamic infarctions and eleven normal controls were evaluated. K-MMSE and the Seoul Neuropsychological Screening Battery were performed within 2 days after stroke. The normalized SPECT data of 4 patients were compared to those of 11 controls for the detection of areas with decreased rCBF by SPM analysis. RESULTS: All 4 patients showed anterograde amnesia in their verbal memory, which was not improved by recognition. Dysexecutive features were occasionally present, such as decreased word fluency and impaired Stroop test results. SPM analysis revealed decreased rCBF in the left supramarginal gyrus, the superior temporal gyrus, the middle and inferior frontal gyrus, the medial dorsal and anterior nucleus of the left thalamus. CONCLUSIONS: The changes of rCBF in patients with left anterior thalamic infarctions may be due to the remote suppression on metabolism by the interruption of the cortico-subcortial circuit, which connects the anterior thalamic nucleus and various cortical areas. The executive dysfunction and dysnomia may be caused by the left dorsolateral frontal dysfunction of the thalamocortical circuit. Anterograde amnesia with storage deficit may be caused by the disruption of mamillothalamic tract.

The Usefulness of Mammography and Scintimammography in Differential Diagnosis of Breast Tumor / 대한핵의학회잡지

PURPOSE: It is very important to differentiate breast cancer from benign mass. There are many reports to evaluate the differential diagnosis under the several diagnostic tools. We evaluated the usefulness of mammography and Tc-99m MIBI scintimammography in the differential diagnosis of breast mass and correlated with pathologic findings. MATERIALS AND METHODS: This study included 80 patients (age: 24-72, mean: 48.4) who underwent mammography and Tc-99m MIBI scintimammography for breast masses. Scintimammographies (anterior-posterior and lateral projections) were acquired in 10 minutes and 2 hours after intravenous injection of Tc-99m MIBI. Four specialists in diagnostic radiology and nuclear medicine evaluated the findings of breast masses under the mammography and Tc-99m MIBI scintimammography, and calculated the tumor to background (T/B) ratio. The pathologic results were obtained and we statistically analyzed the correlations between pathologic results and imaging findings under the mammography and Tc-99m MIBI scintimammography by chi-square and correlation test. RESULTS: The sensitivity, specificity, positive predictive value, and negative predictive value of mammography for detection of breast cancer were 87.5%, 56.3%, 75.0%, and 75.0% respectively. 45 cases of 80 patients were suspicious for breast cancer under the Tc-99m MIBI scintimammography. 41 cases of 45 patients were confirmed as breast cancer and the remaining 4 cases were confirmed as benign masses. The sensitivity, specificity, positive predictive value and negative predictive value of Tc-99m MIBI scintimammography for detection of breast cancer were 85.4%, 87.5%, 91.1%, and 80.8% respectively. The sensitivity of scintimammography was lower than that of mammography for detection of breast cancer, however the specificity, positive predictive value, and negative predictive value were higher. In the benign mass, the mean T/B ratio in 10 minutes was 1.409 +/- 0.30, and that in 2 hours was 1.267 +/- 0.42. The maximal T/B ratio of benign mass in 10 minutes was 1.604 +/- 0.42, and that in 2 hours was 1.476 +/- 0.50. In the malignant mass, the mean T/B ratio in 10 minutes was 2.220 +/- 1.07, and that in 2 hours was 1.842 +/- 0.75. The maximal T/B ratio of malignant mass was 2.993 +/- 1.94, and that in 2 hours was 2.480 +/- 1.34. And the T/B ratio under the early and delayed images were meaningful. CONCLUSION: The scintimammography is useful diagnostic tool to differentiate breast cancer from benign mass, although the sensitivity of mammography for detection of breast mass is high. Especially, the use of the T/B ratio is helpful to diagnose breast cancer.

Different Uptake of Tc-99m ECD and Tc-99m HMPAO in the Normal Brains - Analysis by Statistical Parametric Mapping / 대한핵의학회잡지

No abstract available.

Determination of Representative Renal Depth for Accurate Attenuation Correction in Measurement of Glomerular Filtration Rate in Transplanted Kidney / 대한핵의학회잡지

No abstract available.

SPECT Imaging of Dopamine Transporter with I-123 IPT in Normal Controls and Parkinson's Patients

OBJECTIVES: Dopamine transporter concentrations have been known to decrease in Parkinson's disease(PD). The aim of the present study was to evaluate the correlation between SPECT measurements of [I-123]N-(3-iodopropene-2-yl)-2beta-carbomethoxy-3beta-(4-chlorophenyl) tropane(IPT) as an imaging agent for measuring changes in transporter concentrations with PD. PATIENTS AND METHODS:IPT labelled with 4.87+/-1.29mCi(180.19+/-47.73 MBq) of [I-123] was intravenously injected into 23 patients(age:58+/-12) with PD and three normal controls(NC)(age:37+/-7) as bolus. Brain SPECT were then performed at 1 hour and 2 hours after injection on a double headed camera. The statistical parameters were the contrast ratio of left basal ganglia(BG) and right basal ganglia to occipital cortex(OCC) per milli curies of injected radiotracer at 1 hour and 2 hours. The correlations were evaluated between these parameters and Hoehn-Yahr classification of the patients. RESULTS: The(BG-OCC)/OCC/mCi ratios at 1 hour and 2 hours for PD and NC were 0.14+/-0.07 and 0.27+/-0.07(1 hour) and 0.12+/-0.07 and 0.34+/-0.04(2 hour), respectively. The(BG-OCC)/OCC/mCi ratios of Parkinson's disease were decreased with higher grade of Hoehn-Yahr classification of the patients. The ratio between BG and OCC for PD were clearly separated from NC and may be useful outcome measures for clinical diagnosis. CONCLUSION: The findings suggest that IPT may be a very useful tracer for early diagnosis and treatment of PD and study of dopamine re-uptake site.

Dynamic Salivary Gland Scintigraphy in Clinical Sicca Syndrome: Comparison with Static images / 대한핵의학회잡지

PURPOSE: In this study, we compared the quantitative characteristics of dynamic salivary gland scintigraphy with static scintigraphy in patients with clinical sicca syndrome using Tc-99m pertechnetate. MATERIALS AND METHODS: Fifty-two parotid glands and 52 submandibular glands out of 26 patients with clinical sicca syndrome were studied by dynamic and static salivary gland scintigraphy. Ten normal volunteers were also studied as a control group for comparison of scintigraphic parameters. Ten minutes after injection of 370 MBq Tc-99m pertechnetate, we obtained pre-stimulus static images for a few minutes. Then dynamic salivary gland scintigraphy with lemon juice stimulation was performed for 20 minutes. Finally we obtained post-stimulus static images after dynamic images. On dynamic study, functional parameters such as uptake rate, secretion rate and re-uptake rate were calculated. The results of dynamic study and static images were compared. RESULTS: On dynamic study, we could obtain functional parameters of salivary glands successfully. On dynamic study, 22 parotid glands and 22 submandibular glands out of each of 52 glands are abnormal. The static images demonstrated somewhat different results, of which reasons we could assume via dynamic study. CONCLUSION: Dynamic salivary gland scintigraphy using Tc-99m perechnetate were more functional than static images and might be useful in the assessment of the functional change of the salivary gland in patients with clinical sicca syndrome.

Crossed Cerebellar Diaschisis : Comparison of SPECT, MRI, Clinical Sign

No abstract available.

Which are Risk Factors developing Renal Cortical Defects on 99 mTc - DMSA Scintigraphy in Children with Acute Urinary Tract Infections?

PURPOSE: To determine (1) the relationship between the cortical defects seen on 99 mTc-DMSA renal scans and age, and (2) the presence and degree of vesicoureteral reflux, and then to depict the risk factors for cortical defects in children with acute urinary tract infection (UTI). Furthermore, to assess the diagnostic value of VCUG in predicting a defect on 99 mTc-DMSA renal scans. MATERIALS AND METHODS: We studied 134 kidneys in 67 children aged 15 days-10 years (M:F=39:28) in whom symptomatic UTI was present. In all these children, both DMSA renal scans and voiding cystourethrography (VCUG) were performed. Scanning took place within 7 days of diagnosis and VCUG was performed after one month of diagnosis. Scintigraphic findings were graded according to the extent and number of cortical defects. We evaluated the relationships between the cortical defects seen on DMSA scans and age, and the grade of vesicoureteral reflux. The diagnostic value of VCUG in predicting cortical defects was analysed. Results: The prevalence of cortical defects was greater in patients older than two years (38/54, 70%) than in those aged less than two (38/80, 48%). The frequency of cortical defects was related to vesicoureteral reflux (p or =2yrs) at the time of acute UTI, and high grade of vesicoureteral reflux. The specificity of VCUG in predicting cortical defects is relatively high but the sensitivitiy is low, and a significant proportion of cortical defects therefore occurred in the absence of vesicoureteral reflux.