Evaluation of anxiety and depression in patients prior to myocardial perfusion scintigraphy.

OBJECTIVE: In myocardial perfusion scintigraphy (MPS) negative results indicate coronary artery diseases which might cause prominent anxiety and other psychological reactions. The aim of this study was to determine anxiety and depression levels of patients prior to MPS procedures. METHODS: The Hospital Anxiety Depression Scale(HADS) and the State and Trait Anxiety Inventory I and II were used to evaluate the anxiety and depression levels of the patients. Descriptive analyses and independent sample t-test were used for statistical assessment. RESULTS: The mean score of HADS-anxiety score prior to MPS was 8.1 ± 4.2, whereas the mean HADS depression score was 6.1 ± 3.7. The mean state anxiety score prior to MPS was 39.7 ± 10.6 and the mean trait anxiety score was 45.02 ± 9.1. HAD and state and trait anxiety scores were found to be significantly higher in female patients than male patients and non-smoker patients than smoker patients. Other risk factors such as having bypass operation, myocardial infarction, hypercholesterolemia, diabetes and hypertension were not related to depression and anxiety scores. CONCLUSION: The results in this study suggest a role for MPS as a risk factor for higher state anxiety. The MPS procedures might lead to an increase in anxiety levels of patients which is possibly associated with anticipation anxiety felt during waiting period and expectation life-threatening.

Urinary MMP-9/NGAL complex in children with acute cystitis.

The matrix metalloproteinase-9 (MMP-9) and neutrophil gelatinase associated lipocalin (NGAL) are shown to increase in an inflammatory situation. Based on our previous reports that NGAL can be detected in the urine of children with urinary tract infection (UTI), we also asked whether MMP-9/NGAL complex could be detected in the urine of children with UTI. This multicenter, prospective study was conducted between October 2009 and October 2010. Seventy-one patients with symptomatic culture proven UTI, 37 asymptomatic children with contaminated urine and 37 healthy children were recruited. Mean uMMP-9/NGAL/Cr levels were significantly higher in the UTI group than in the control group (p < 0.0001). According to ROC analysis, the optimal cut-off level was 0.08 ng/mg to predict UTI. Using a cut-off value, sensitivity and specificity were 98.6 and 97.3%, respectively. The mean levels of uMMP-9/NGAL/cr in the UTI group were also significantly higher than those in the contamination group (p < 0.0001). There was no statistically significant difference between contamination group and the control group (p = 0.21). The mean uMMP-9/NGAL/Cr in the UTI group were significantly higher before treatment than after treatment (p < 0.0001). The area under the curve was 0.997 (SE: 0.002, 95% CI: 0.993 to 1.001) for uMMP-9/NGAL/Cr. Urinary MMP-9/NGAL/Cr level was also correlated with positive urine nitrite test, positive urine leukocyte esterase reaction and renal scarring (p = 0.0001, p = 0.0001, p = 0.04, respectively) whereas was not correlated to leukocytosis and positive CRP level in serum. Urine MMP-9/NGAL/cr can be used as a diagnostic biomarker for UTI in children. Identification of NGAL-MMP-9/cr levels in the urine of suspected UTI patients may also be useful to differentiate between contamination and infection and for monitoring of treatment response in children.

Clearance of the high intestinal (18)F-FDG uptake associated with metformin after stopping the drug.

PURPOSE: This study was done to determine whether interruption of metformin before (18)F-FDG PET/CT imaging could prevent the increased (18)F-FDG uptake in the intestine caused by this drug. METHODS: Included in the study were 41 patients with known type 2 diabetes mellitus who were referred to our department for evaluation of various neoplastic diseases. Patients underwent two (18)F-FDG PET/CT scans, the first while they were on metformin and the second after they had stopped metformin. They stopped metformin and did not take any other oral antidiabetic medication starting 3 days before the second study and their blood glucose level was regulated with insulin when necessary to keep it within the range 5.55-8.33 mmol/l. FDG uptake was graded visually according to a four-point scale and semiquantitatively by recording the maximum standardized uptake value (SUVmax) in different bowel segments. A paired-samples t-test method was used to determine whether there was a significant difference between SUVmax measurements and visual analysis scores of the metabolic activity of the bowel in the PET/CT scans before and after stopping metformin. RESULTS: Diffuse and intense (18)F-FDG uptake was observed in bowel segments of patients, and the activity in the colon was significantly decreased both visually and semiquantitatively in PET/CT scans performed after patients stopped metformin (p<0.05). There was a statistically significant decrease in activity in the small intestine on visual analysis (p<0.05), but semiquantitative measurements did not show a significant decrease in the SUVmax values in the duodenum or jejunum (p>0.05). CONCLUSION: Metformin causes an increase in (18)F-FDG uptake in the bowel and stopping metformin before PET/CT study significantly decreased this unwanted uptake, especially in the colon, facilitating the interpretation of images obtained from the abdomen and preventing the obliteration of lesions.

Urinary macrophage migration inhibitory factor in children with urinary tract infection.

Macrophage migration inhibitory factor (MIF) plays an essential pathophysiological role in inflammatory reactions. The aim of this study was to investigate the clinical utility of urine MIF (uMIF) level in predicting urinary tract infections (UTI). This multicenter, prospective study was conducted over a 1-year period between March 2008 and March 2009. Sixty patients with symptomatic culture-proven UTI and 29 healthy children were recruited. Urine MIF was measured by enzyme-linked immunosorbent assay. The mean MIF level was found to be significantly higher in the UTI group than in the control group (1082.82 vs. 211.45 pg/ml, p = 0.0001). Receiver operating characteristic (ROC) analysis revealed that the optimal cut-off uMIF level was 295 pg/ml for uMIF to predict UTI. The sensitivity and specificity of this cut-off level were 91.7% and 69%, respectively. Mean uMIF/creatinine (Cr) was also significantly higher in the UTI group than in the control group (2400.69 vs. 267.56 pg/mgCr, p = 0.0001). At a cut-off of 815 pg/mgCr for uMIF/Cr, the sensitivity and specificity were 95 and 79%, respectively. The area under curve (AUC) was 0.848 (standard error 0.040, 95% confidence interval 0.756-0.915) for uMIF and 0.889 (0.034, 0.805-0.946) for uMIF/Cr. Urine MIF/Cr was significantly higher in the patients with a positive leukocyte esterase reaction in the urine (p = 0.047), leukocytosis (p = 0.0001) and positive C-reactive protein level in serum (p = 0.003). The uMIF level was not related to leukocytosis, positive CRP level in serum and leukocyte esterase reaction in the urine. Neither uMIF nor uMIF/Cr were correlated to the positive urine nitrite test, pyuria, urine pH and specific gravity (p > 0.05). These results suggest that urine MIF and uMIF/Cr can be used for the early prediction of UTI in children.

The efficacy of (99m)Tc-MIBI scintimammography in the evaluation of breast lesions and axillary involvement: a comparison with X-rays mammography, ultrasonography and magnetic resonance imaging.

This study was performed because the efficacy of technetium-99m methoxyisobutyl isonitrile scintimammography ((99m)Tc-MIBI-SM) in the evaluation of the breast lesions and axillary lymph node involvement in comparison with X-rays mammography (XRM), ultrasonography (US) and magnetic resonance imaging (MRI) has not been fully investigated. Forty six female patients were included in this study, with suspicious lesions detected in their breasts by palpation, by imaging modalities or clinically. All patients underwent (99m)Tc-MIBI-SM, US and MRI for the evaluation of breast lesions. All patients according to clinical situation and imaging studies underwent fine needle aspiration, mass extirpation, core biopsy, modified radical mastectomy or partial lumpectomy in order to confirm the nature of the lesions. Our results showed that (99m)Tc-MIBI-SM detected 15 of 16, US 11 of 16, XRM 13 of 16 and MRI 13 of 16 malignant lesions. Sensitivities were 93%, 68%, 81% and 81%, respectively. Among these cases there were 4 of 15 false positive (FP) results on SM whereas 4 of 11 on US, 11 of 13 on XRM and 8 of 13 on MRI. The specificities of the above modalities were 86%, 87%, 63% and 73%, respectively. The sensitivities of the above imaging modalities for the detection of axillary lymph node metastases were 55%, 55%, 11% and 77% for SM, US, XRM and MRI, respectively. The sensitivity and specificity of SM for the palpable lesions (n=31) were 100% and 84% and for the nonpalpable lesions (n=15) were 75% and 90%, respectively. In conclusion, although the number of patients studied was small it is the opinion of the authors that (99m)Tc-MIBI-SM has a much better sensitivity and less FP results in detecting malignant breast lesions than the other 3 modalities and also better sensitivity than XRM and MRI. Thus (99m)Tc-MIBI-SM can be included in the diagnostic algorithms for detecting malignancy in breast tumors.

Differentiated thyroid carcinoma in children: Clinical characteristics and long-term follow-up.

Differentiated thyroid cancer (DTC) is rare in children, but it still remains the most common endocrine malignancy in children. The aim of this study was to analyze treatment response to radioactive iodine (RAI) therapy, clinical outcomes, recurrences, survival analysis, and long-term follow-up. We retrospectively reviewed the medical records of 43 pediatric patients (≤17 years of age) with DTC diagnosis after thyroidectomy who were treated with RAI. The follow-up protocol consisted of detailed clinical examination, testing of thyroid function, determination of serum thyroglobulin (Tg), and anti-Tg antibodies, and neck ultrasonography application. Forty-three pediatric patients (34 females and 9 males) treated with RAI for DTC in our institute. The median follow-up period was 54 months. The histologic classification was papillary thyroid cancer in 41 patients and the remaining 2 patients had follicular thyroid cancer. After the long-term follow-up, complete remission, partial remission, and recurrent-persistent disease were observed in 37 patients, 3 patients, and 3 patients, respectively. Among the series, 1 death occurred due to multiple metastases. The mortality rate is 2.56%. Total thyroidectomy followed by RAI appears to be the most effective treatment for patients with pediatric DTC in terms of reducing the rate of relapse and improving surveillance for recurrent disease.

Early prediction of urinary tract infection with urinary neutrophil gelatinase associated lipocalin.

Neutrophil gelatinase associated lipocalin (NGAL) is a protein identified in human neutrophil granules. The aim of the study was to assess whether urine level of NGAL (uNGAL) could represent a novel, reliable marker of urinary tract infection (UTI) and to determine the optimal cutoff level for uNGAL to predict UTI in children. Sixty patients with symptomatic UTI and 29 healthy controls were enrolled the study. Urine NGAL was measured by enzyme-linked immunosorbent assay. A dimercaptosuccinic acid (DMSA) radionuclide scan was performed within 7 days in the patients with UTI in an attempt to distinguish pyelonephritis from cystitis. Mean uNGAL level was significantly higher in the UTI group than in the controls (91.02 ng/ml vs 14.29 ng/ml, p = 0.0001) and using a cutoff 20 ng/ml for uNGAL for diagnosis of UTI, sensitivity, and specificity were 97% and 76%, respectively [area under the curve (AUC): 0.979]. Mean uNGAL/creatinine ratio (uNGAL/Cr) was also significantly higher in the UTI group [201.81 ng/mg creatinine (Cr) vs 18.08 ng/mg Cr; p = 0.0001], and using a cutoff 30 ng/mg Cr for uNGAL/Cr for diagnosis of UTI, sensitivity and specificity were 98% and 76%, respectively (AUC: 0.992). In conclusion, both uNGAL and uNGAL/Cr can be used as a novel, sensitive marker for early prediction of UTI in the absence of acute kidney injury and chronic kidney disease, and the optimal cutoff value for prediction of UTI is lower than the values determined for acute kidney injury. Further investigations with larger patient groups are required to confirm our results.

Gamma probe (99m)Tc-pertechnetate assisted completion thyroidectomy vs conventional thyroidectomy in differentiated thyroid carcinoma.

Patients undergoing partial thyroidectomy for benign diseases may need re-operation if differentiated thyroid carcinoma (DTC) is detected on histopathology. The aim of this study was to determine if using gamma probe during the above surgery in a procedure called: gamma probe completion thyroidectomy (GPCT) could support the diagnosis of DTC tissue and offer an advantage in the surgical treatment of DTC patients. We have studied 100 patients who after bilateral subtotal thyroidectomy for benign disease in several hospitals, were found to have DTC histopathologically and referred to our clinic for subsequent re-operation. Of these, 50 underwent conventional completion thyroidectomy (Group I) and 50 underwent GPCT (Group II). We compared retrospectively Group I and Group II in terms of volume of residual thyroid tissue, thyroid stimulating hormone (TSH) values, complication rates and incidence of tumor found in the residual thyroid. Our results showed that one month postoperatively, TSH was significantly higher in Group II (P<0.001). Volumes of residual thyroid were also significantly less in Group II (P<0.000). Complications and the incidence of tumor cells found in the residual thyroid tissue between the groups were not statistically different (P>0.05). In conclusion, GPCT in patients with DTC significantly increased the success of this operation in localizing and removing residual thyroid tissue.

The Value of Attenuation Correction in Hybrid Cardiac SPECT/CT on Inferior Wall According to Body Mass Index.

The purpose of this study was to evaluate the diagnostic value of attenuation-corrected single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) on the inferior wall compared to uncorrected (NC) SPECT MPI between obese and nonobese patients. A total of 157 consecutive patients (122 males and 35 females, with median age: 57.4 ± 11 years) who underwent AC technetium 99m-methoxyisobutylisonitrile (AC Tc99m-sestamibi) SPECT MPI were included to the study. A hybrid SPECT and transmission computed tomography (CT) system was used for the diagnosis with 1-day protocol, and stress imaging was performed first. During attenuation correction (AC) processing on a Xeleris Workstation using Myovation cardiac software with ordered subset expectation maximization (OSEM), iterative reconstruction with attenuation correction (IRAC) and NC images filtered back projection (FBP) were used. For statistical purposes, P < 0.05 was considered significant. This study included 73 patients with body mass index (BMI) <30 and 84 patients with BMI ≥ 30. In patients with higher BMI, increased amount of both visual and semiquantitative attenuation of the inferior wall was detected. IRAC reconstruction corrects the diaphragm attenuation of the inferior wall better than FBP. AC with OSEM iterative reconstruction significantly improves the diagnostic value of stress-only SPECT MPI in patients with normal weight and those who are obese, but the improvements are significantly greater in obese patients. Stress-only SPECT imaging with AC provides shorter and lower radiation exposure.

The effect of high dose radioiodine therapy on formation of radiation retinopathy during thyroid cancer treatment.

OBJECTIVE: Non-thyroidal complication of high-dose radioiodine therapy for thyroid carcinoma might cause salivary and lacrimal gland dysfunction, which may be transient or permanent in a dose-dependent manner. However, radiation retinopathy complicating 131I therapy, has not been previously well characterized. The aim of this study was to evaluate the extent of retinal damage among patients who had received high doses of radioiodine treatment. METHODS: Forty eyes of 20 patients (3 male, 17 female) who received 250-1000 mCi during 131I therapy and on ophthalmological follow up for a year after the last treatment were included in the study. Mean age of the study group was 50 years (range 25-70 years). In ophthalmologic examination, visual acuity was measured in order to determine visual loss. Intraocular pressure was measured in all the patients. Then lens examination was carried out with slit lamp biomicroscopy in order to investigate cataract or partial lens opacities. Fundus observation was carried out through the dilated pupil with slit lamp biomicroscopy using 90 D noncontact lens. RESULT: The best corrected visual aquity with Snellen chart was found as 1.0 in 36 eyes (90%) and between 0.6 and 0.9 (10%) in 4 eyes (10%). At the biomicroscopic fundus examination, retinal hemorrhage consistent with radiation retinopathy, microaneurysm, microinfarction, edema or exudation, vitreus hemorrhage, partial or total optical disc pallor indicating papillopathy in the optic disc were not observed in any of the eyes. CONCLUSION: This result indicates that there is not any significant correlation between repeated high-dose radioiodine therapy and radiation retinopathy in differentiated thyroid carcinomas. Even though there is not a significant restriction in use of higher doses of radioiodine therapy in differentiated thyroid carcinoma, more extensive studies are needed in order to obtain more accurate data on possible occurrence of retinopathy.

Gamma Probe Guided Minimally Invasive Parathyroidectomy without Quick Parathyroid Hormone Measurement in the Cases of Solitary Parathyroid Adenomas.

OBJECTIVE: In this study, our aim was to study the efficiency of gamma probe guided minimally invasive parathyroidectomy (GP-MIP), conducted without the intra-operative quick parathyroid hormone (QPTH) measurement in the cases of solitary parathyroid adenomas (SPA) detected with USG and dual phase 99mTc-MIBI parathyroid scintigraphy (PS) in the preoperative period. MATERIAL AND METHODS: This clinical study was performed in 31 SPA patients (27 female, 4 male; mean age 51±11years) between February 2006 and January 2009. All patients were operated within 30 days after the detection of the SPA with dual phase 99mTc-MIBI PS and USG. The GP-MIP was done 90-120 min after the iv injection of 740 MBq 99mTc-MIBI. In all cases, except 1 patient, the GP-MIP was performed under local anesthesia; due to the enormity of size of SPA, then general anesthesia is chosen. RESULTS: The operation time was 30-60 min, mean 38,2±7 min. In the first postoperative day, there was a more than 50% decrease in PTH levels in all patients and all but one had normal serum calcium levels. Transient hypocalcemia was detected in one patient. CONCLUSION: GP-MIP without intra-operative QPTH measurement is a suitable method in the surgical treatment of SPA detected by dual phase 99mTc-MIBI PS and USG. CONFLICT OF INTEREST: None declared.

Serum resistin and insulin-like growth factor-1 levels in patients with hypothyroidism and hyperthyroidism.

Introduction. The aim of this study was to evaluate the serum levels of resistin and insulin-like growth factor-1 (IGF-1) and and also the potential relationship between thyroid function and levels of resistin and IGF-1 in hypothyroid and hyperthyroid patients. Methods. Fifteen cases of hypothyroid (HT), 16 of subclinically hypothyroid (SCHT), 15 of hyperthyroid (HrT), 15 of subclinically hyperthyroid (SCHrT), and 17 healthy individuals have been included in the study. Serum resistin levels were measured using enzyme-linked immunosorbent assay and IGF-1 and thyroid stimulating hormone (TSH) levels by chemiluminescence method. Results. Resistin levels in total HT group were significantly higher than in controls (12.66 ± 6.04 and 8.45 ± 2.90 ng/mL, resp.). In SCHrT subgroup resistin levels were significantly higher than those of controls (14.88 ± 7.73 and 8.45 ± 2.90 ng/mL, resp.). IGF-1 levels were significantly lower in total HT than in total HrT and control groups (117.22 ± 52.03, 155.17 ± 51.67, and 184.00 ± 49.73 ng/mL, resp.). Furthermore IGF-1 levels in HT subgroup were significantly lower compared to controls (123.70 ± 44.03 and 184 ± 49.73 ng/mL, resp.). In SCHT subgroup IGF-1 levels were significantly lower than those of control and SCHrT groups (111.11 ± 59.35, 184.00 ± 49.73, and 166.60 ± 47.87 ng/mL, resp.). There were significant correlations between IGF-1 and TSH in HT subgroup and between resistin and TSH in total HrT group. Conclusion. It was concluded that increased resistin levels are directly related to thyroid dysfunction, and GH/IGF-1 axis is influenced in clinically or subclinically hypothyroidism patients.

Use of benzodiazepines before (18)F-FDG-PET/CT dual-phase imaging does not decrease the efficacy of the study.

PURPOSE: We aimed to investigate whether administration of benzodiazepines decreases the efficacy of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography PET/CT) ((18)F-FDG-PET/CT) dual-phase imaging. MATERIALS AND METHODS: Eighteen patients with malignant tumors who were administered 0.5 mg alprazolam before undergoing (18)F-FDG-PET/CT scan (group A) and 21 patients with malignant tumors who were not administered alprazolam before (18)F-FDG-PET/CT scan (group B) were included in this study. Forty lesions from the 18 patients in group A and 66 lesions from the 21 patients in group B were evaluated. Initial "early" whole-body imaging commenced 60 ± 5 minutes after injection of (18)F-FDG and delayed scan was obtained 120 ± 10 minutes after the injection. Maximum standardized uptake values (SUVs) were obtained by drawing three-dimensional regions of interest (ROIs) around each lesion on the early study and the corresponding lesion on the delayed study. RESULTS: The average SUVmax in lesions in group A (mean ± S.D.) was 10.2 ± 6.4 on early examination (SUVmax E) and 12.6 ± 7.6 on delayed examination (SUVmax D). There was a significant difference between these two time points (P < 0.05). Similarly, for the lesions in group B, the average uptake values were 9.3 ± 5.2 (SUVmax E) and 11.2 ± 6.5 (SUVmax D). The increase in these values was significant as it was in group A (P < 0.05). Differences between groups A and B for the variables SUVmax E, SUVmax D were not significant statistically (P > 0.05). CONCLUSION: Benzodiazepines do not adversely affect the efficacy of the dual-phase FDG-PET imaging technique.

Unusual F-18 FDG Uptake at the Ears of a Patient with Discoid Lupus Erythematosus Diskoid Lupus Eritamatozus.

UNLABELLED: A 55-year-old patient, who had undergone excisional biopsy of upper lip two years ago and diagnosed to have squamous cell carcinoma, was referred to us for evaluation with Fluorine-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET)/CT (F-18 FDG-PET/CT) scan. F-18 FDG-PET/CT scan was performed and the maximum intensity projection images (MIP) showed unusual FDG uptake at both ears. Histopathological examination of the biopsy specimen obtained from the ears revealed discoid lupus erythematosus (DLE). CONFLICT OF INTEREST: None declared.

Intraocular and orbital metastasis as a rare form of clinical presentation of insular thyroid cancer.

Insular carcinoma of thyroid is a rare tumor, which accounts for 4 to 6% of thyroid malignancies. Clinically and morphologically it is considered to be in an intermediate position between well-differentiated carcinoma of the thyroid (papillary or follicular) and undifferentiated or anaplastic carcinoma of the thyroid. Capsular and blood vessel invasion is seen frequently, and metastases to regional lymph nodes, lungs and bones are common. The initial presentation of distant metastasis in patients with thyroid cancer is rare. Thus metastatic thyroid carcinoma rarely involves the orbit. We report a rare case of choroidal metastasis from insular thyroid carcinoma.

Investigation of the efficacy of 99 mTc-DTPA scintigraphic GFR measurement with Gates method in the detection of cisplatin-induced nephrotoxicity in comparison with plasma urea and creatinine measurement.

In this study, we investigated the efficacy of 99mTc-DTPA scintigraphic analysis of GFR with the Gates method in comparison with the measurement of plasma urea and creatinine, in the detection of nephrotoxicity occurred in patients treated with cisplatin.Twenty-six male patients with a mean age of 26.73±6.39 years (age range 15-42) who had seminomatous and nonseminomatous testicular carcinoma were included in our study. The patients received cisplatin with a dose of 20 mg/m2 per day for five consecutive days repeated every 21 days. Before starting chemotherapy, immediately after the end of four cycles of chemotherapy and 7 months after the beginning of chemotherapy, plasma urea and creatinine levels were measured and simultaneously scintigraphic GFR estimation using 99 mTc-DTPA with the Gates method was performed. In the measurements done immediately after the chemotherapy, in 18 of the 26 patients GFR levels decreased, in 4 of the 8 remaining patients GFR did not change, and in 4 patients there was an increase in the GFR levels. The changes in the averages of the plasma urea and creatinine levels between measurements done before and after the chemotherapy were not statistically significant. The decrease in the average of the GFR values immediately after chemotherapy, in comparison to the average of GFR values measured before chemotherapy, was found to be statistically significant with paired sample t test analysis (P<0.009 with 95% CI). We concluded that scintigraphic GFR measurement using the Gates method with 99mTc-DTPA is a suitable method in the diagnosis of nephrotoxicity occuring due to cisplatine.

A prospective diagnostic accuracy study of F-18 fluorodeoxyglucose-positron emission tomography/computed tomography in the evaluation of indeterminate renal masses.

PURPOSE: We evaluated the efficacy of fluorine-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET)/computerized tomography (CT; F-18 FDG-PET/CT) in the detection of renal cell carcinoma (RCC) in patients with indeterminate renal masses. MATERIALS AND METHODS: Between December 2008 and June 2010, 18 patients with suspicious primary renal masses detected by conventional imaging underwent FDG PET/CT imaging. All patients underwent nephrectomy or surgical resection of the renal mass and the final diagnoses were based on histopathology. RESULTS: Fifteen patients had RCC (14 clear-cell RCC, one papillary RCC). Three renal tumors were benign, corresponding to two renal cortical cysts and one oncocytoma. FDG PET/CT accurately detected seven malignant lesions and yielded false-negative results in eight patients. FDG PET/CT was true negative in two patients with a renal cortical cyst and false positive in a patient with oncocytoma. PET showed a sensitivity of 46.6%, specificity of 66.6%, and accuracy of 50% for primary RCC tumors. The median size of visualized tumors was greater than the median size of nonvisualized tumors, and the average Fuhrman grade of the patients with FDG-positive malignant lesions were higher than that of the patients with FDG-negative lesions. In malignant tumors, the change between early and delayed imaging for average standardized uptake values and maximum SUVs were not statistically significant. CONCLUSION: FDG PET/CT is not a reliable modality in the diagnosis of RCC with its low sensitivity, but it is effective in the detection of distant metastases and can be used as a complementary tool when conventional imaging studies yield equivocal results.