Tanju Yusuf Erdil

Correlation of technetium-99m MIBI and thallium-201 retention in solitary cold thyroid nodules with postoperative histopathology

Abstract.A comparative prospective study of technetium-99m methoxyisobutylisonitrile (MIBI) and thallium-201 with early (15 min) and delayed (90 min for MIBI, 3 h for 201Tl) imaging in the differentiation of thyroid lesions is presented. Forty patients with cold thyroid nodules visualised on 99mTc-pertechnetate scan and with dyskaryotic or atypical epithelial cells verified by fine-needle aspiration biopsy underwent MIBI and 201Tl scintigraphy at 3-day intervals. Subsequent thyroidectomies were carried out in all patients. Semiquantitative analysis was performed using a lesion to non-lesion ratio on early (ER) and delayed images (DR). Additionally, a retention index (RI) was calculated using the formula RI=(DR– ER) × 100/ER. The reproducibility of the method for the early and delayed measurements was tested by analysing intra- and inter-observer variability and repeatability coefficients. Histopathologically, the nodules were found to be well-differentiated thyroid cancer in 21 patients and benign in 19 patients. There was no significant difference in the ER between malignant and benign lesions for either 201Tl or MIBI (P>0.05). However, for both agents significant differences were found between malignant and benign lesions with regard to DR (P<0.01 for 201Tl and P<0.001 for MIBI) and RI (P<0.001 for both agents). Statistical comparison of the two agents showed no significant differences (P>0.05) except with regard to DR and RI in malignant nodules (P<0.05). A receiver operating characteristic analysis was performed to determine threshold levels for the differentiation of malignant from benign nodules. Following this analysis, ER, DR and RI levels of 1.03, 1.54 and 2 for MIBI and ≤1.42, 1.24 and 5 for 201Tl were selected. Using these threshold levels, the sensitivity, specificity and accuracy of the study were 90.5%, 36.8% and 65% for ER MIBI, 61.9%, 94.7% and 77.5% for DR MIBI, 95.2%, 89.4% and 92.5% for RI MIBI, 85.7%, 47.3% and 67.5% for ER 201Tl, 80.9%, 73.6% and 77.5% for DR 201Tl, and 90.5%, 94.7% and 92.5% for RI 201Tl. In conclusion, the DR for MIBI and 201Tl is superior to the ER in detecting malignant nodules, and the RI for both MIBI and 201Tl is more valuable than the DR in differentiating malignant from benign thyroid nodules.

Contradictory supranormal function in hydronephrotic kidneys: fact or artifact on pediatric MAG-3 renal scans?

Objectives: Contradictory supranormal renal function (SRF) in unilateral hydronephrosis is a debatable subject resulting from the methodology of nuclear renography or the characteristics of the patient. In this study, we aimed to investigate the frequency and comparison of SRF with MAG-3 scans by 8 different technical analyses in pediatric hydronephrosis. Methods: We reviewed Tc-99m MAG-3 scans in 82 children with unilateral hydronephrosis (52 male, 30 female, mean age: 47.7 ± 64.5 months). Of 82, 34 also had Tc-99m DMSA scans. Data were reprocessed with 4 different regions of background activity (subrenal, perirenal C-type, perirenal ring, and lateral) at 2 different time intervals (1–2 and 2–3 minute), and 8 different estimates of MAG-3 differential renal function (DRF) were obtained in 67 patients. SRF was defined as DRF greater than 55% in the hydronephrotic kidney. Results: The routine processing protocol showed only 3 renal units with SRF, and all were on the right side (3.6%). After reprocessing, a total of 10 dilated kidneys had SRF in 1 or more of DRF estimates (5.2% of all estimations). These cases were significantly younger (8.1 ± 6.7 vs. 42.5 ± 52.5, P < 0.05) and had a larger renal area ratio (1.25 ± .24 vs. 1.07 ± .21, P < 0.05). There was no SRF with DMSA. In comparison between MAG-3 and DMSA DRF in 20 children who underwent both tests within 3 months, the best correlation was obtained when C-type correction was used for both agents at 2 time intervals (r: .86 and .84 for early and late time intervals, P < 0.00001, respectively). Conclusions: SRF in unilateral hydronephrosis is, at least, in part, technical in origin in this particular pediatric patient population with tubular immaturity (ie, physiological high background activity) and asymmetric kidney size.

Comparison of WHO, RECIST 1.1, EORTC, and PERCIST criteria in the evaluation of treatment response in malignant solid tumors.

AimTo compare response assessment according to the WHO, RECIST 1.1, EORTC, and PERCIST criteria in patients diagnosed with malignant solid tumors and who had received cytotoxic chemotherapy to establish the strength of agreement between each criterion. Materials and methodsSixty patients with malignant solid tumors were included in this retrospective study. The baseline and the sequential follow-up fluorine-18-fluorodeoxyglucose PET/computed tomography (CT) of each patient were evaluated according to the WHO, RECIST 1.1, EORTC, and PERCIST criteria. PET/CT images were used for both metabolic and anatomic evaluation. The concurrent diagnostic CT and MRI images (performed within 1 week of PET/CT) were also utilized when needed. The results were compared using the &kgr;-statistics. ResultsThe response and progression rates according to the WHO criteria were 37 and 38%, respectively. The same ratios were also found for RECIST 1.1 (&kgr;=1). The response and progression rates according to the EORTC criteria were 47 and 40%, respectively. When PERCIST criteria were used, one patient with progressive disease was upgraded to stable disease (&kgr;=0.976). As we found the same results with WHO and RECIST 1.1 criteria, we used WHO criteria to compare the anatomic and metabolic criteria. When we compared the WHO and EORTC criteria, there was an agreement in 80% of the patients (&kgr;=0.711). With WHO and PERCIST criteria, there was an agreement in 81.6% of the patients (&kgr;=0.736). ConclusionSignificant agreement was detected when the WHO, RECIST 1.1, EORTC, and PERCIST criteria were compared both within as well as between each other.

False Positive FDG PET/CT Resulting from Fibrous Dysplasia of the Bone in the Work-Up of a Patient with Bladder Cancer: Case Report and Review of the Literature

Fibrous dysplasia of the bone (FDB) is a common, genetic, developmental disorder with a benign course. FDB can be seen anywhere throughout the skeleton. It is usually asymptomatic and found incidentally on imaging studies that are performed for other purposes. Although whole body 18 F-flourodeoxyglucose PET/CT (FDG PET/CT) is widely used in tumor imaging, infections and benign pathologies like FDB may cause false positive results. Herein we report the case of a 48-year-old FDB patient with transitional cell carcinoma of the urinary bladder. Restaging FDG PET/CT showed multiple mild to moderate hypermetabolic bone lesions which were initially misinterpreted as bone metastases. In this case report, we aimed to guide physicians in evaluating bone lesions in cancer patients with FDB in the light of the literature.

The role of 99Tcm-tetrofosmin in the evaluation of thyroid nodules

Various radionuclides, including 67Ga, 201Tl and 99Tcm-sestamibi, have been used to differentiate benign from malignant thyroid nodules. 99Tcm-tetrofosmin, a lipophilic cationic radiotracer, and 99Tcm-sestamibi have also been reported to accumulate in thyroid tumours. In this study, we evaluated the role of 99Tcm-tetrofosmin in the differentiation of malignant from benign thyroid nodules. Seventy-nine patients with solitary non-functioning thyroid nodules were included in the study. Fine-needle aspiration biopsy was performed in all patients. Sixty patients were subsequently operated on and 19 patients refused surgery. After the injection of 370 MBq 99Tcm-tetrofosmin, static images at 5, 30, 60, 120 and 180 min were acquired. Both visual and semi-quantitative analysis was performed. On visual interpretation, the nodules with late retention were classified as positive for malignancy and nodules without late retention were classified as negative for malignancy. In the semi-quantitative analysis, regions of interests were drawn over the nodule and contralateral normal thyroid tissue. The average number of counts was recorded and tumour-to-normal thyroid tissue ratios calculated. Post-operative histology revealed 19 malignant and 41 benign nodules. Of the benign nodules, adenomas behaved similarly to the malignant nodules with late retention of tracer, while adenomatous nodules revealed no late retention on delayed images and could be differentiated from malignant tumours. In the semi-quantitative analysis, there was a significant difference in tumour-to-normal tissue ratios for adenomatous nodules and malignant tumours as well as adenomas. We conclude that it is not possible to differentiate between malignant and benign thyroid nodules with 99Tcm-tetrofosmin. However, 99Tcm-tetrofosmin scintigraphy is helpful in selecting nodules that can be cured by surgical intervention.

The clinical utility of 99mTc-HMPAO SPECT in Fahr’s disease

Fahr’s disease is a rare neurodegenerative syndrome, characterized by massive symmetrical intracerebral calcifications of the basal ganglia, dentate nuclei of the cerebellum, and the adjacent parenchyma. Computerized tomography (CT) is considerably more sensitive to detect these intracranial calcifications than other imaging modalities. The clinical, CT scan, and 99mTc-D,L-hexamethylpropylene amine oxime (99mTc-HMPAO) brain perfusion single-photon emission computerized tomography (SPECT) findings in a 42-year-old woman with Fahr’s disease are reported, and the clinical utility of 99mTc-HMPAO SPECT findings in Fahr’s disease is discussed in this article. In conclusion, 99mTc-HMPAO brain perfusion SPECT seems to be useful in the clinical approach to Fahr’s disease, and may provide more specific and clinically relevant information when compared with anatomical imaging.

RIGHT BASAL GANGLION HYPOPERFUSION IN OBSESSIVE COMPULSIVE DISORDER PATIENTS DEMONSTRATED BY Tc-99m-HMPAO BRAIN PERFUSION SPECT: A CONTROLLED STUDY

The aim of this study is to demonstrate the regional cerebral blood flows (rCBF) of obsessive-compulsive disorder (OCD) patients compared to controls by using Tc-99m-HMPAO SPECT. Sixteen OCD and seven control subjects were admitted into the study. Yale-Brown Obsessive Compulsive Rating Scale (Y-BOCS), Hamilton Depression Rating Scale (HDRS), and Hamilton Anxiety Rating Scale (HARS) were applied to the patients. The rCBF was found to be decreased in right basal ganglion in OCD patients. The right basal ganglion rCBF was negatively correlated with Y-BOCS total and compulsion scores. The left thalamus rCBF was negatively correlated with Y-BOCS obsession score. Right and left cingulate rCBF were negatively correlated with HDRS score. The results indicating hypoperfusion in right basal ganglion in OCD patients support previous findings about dysfunction of frontal-subcortical circuits in this disorder.

99mTc-MDP- and 18F-FDG-avid metastatic liver lesion: the similarities and differences between 2 modalities.

Although 99mTc-MDP uptake in the extraskeletal tissues was presented before in the literature, FDG PET/CT and conventional bone scan findings have not been discussed together yet. Herein, we presented 99mTc-MDP- and 18F-FDG-avid metastatic liver lesion in a breast cancer patient and compared 2 modal

Evaluation of physiological FDG uptake in the skeleton in adults: Is it uniformly distributed?

AIM The aim of this study was to study whether FDG was uniformly distributed throughout the skeleton and whether age and gender affected this biodistribution. MATERIAL AND METHODS A total of 158 patients were included in this retrospective study. None of the patients had received prior treatment that had affected the bone marrow and patients with bone metastases, trauma, benign and/or malignant hematologic disorders were excluded from the study. The SUVmax from the 24 different locations in the skeleton was obtained and all the values were compared with each other. RESULTS FDG uptake in the skeleton was not uniform in both sexes. While the highest FDG uptake was seen in the L3 vertebra, the lowest glucose metabolism was observed in the diaphysis of the femur. Concerning the vertebral column, FDG uptakes were also non-uniform and the SUVmax gradually increased from the cervix to the lumbar spine. The mean skeletal SUVmax was decreased in accordance with age in both genders. CONCLUSION FDG was not uniformly distributed throughout the skeleton in both sexes. It had a tendency to increase from the appendicular to axial skeleton and from cervical to lumbar spine in the vertebral column that may be related with the normal distribution of the red bone marrow. Additionally, the glycolytic metabolism of the whole skeleton was gradually decreased in accordance with the age in both sexes.

Breast cancer lung metastases incidentally detected on bone SPECT/CT: A rare finding that might be missed on whole body scan

A 87-year-old female breast cancer patient followed-up for 6 ears without any known metastasis was referred to bone scintigaphy with low back pain and slightly increased tumor markers [CA 5–3 = 37 U/ml (normal levels = 4.50–25.0 U/ml)]. The initial stage f the tumor was T2N1M0 (Stage 2B) and the patient received horonal treatment after left modified radical mastectomy. Two hours fter the injection of 740 MBq 99mTcMDP, whole body bone scan as performed. It revealed increased, heterogenous osteoblastic ctivity in the spine suggestive of degenerative changes (probale cause of the patient’s primary complaint) and a focal increased racer uptake in the right ninth rib which was consistent with atient’s previous history of trauma. Additionally, two foci of ncreased activity projecting over the anterior tip of the 4th rib and eft 8th intercostal space on posterior image were also seen (Fig. 1). horacic SPECT/CT was performed for anatomical correlation of he findings. Degenerative changes in the spine and posttraumatic allus formation around the right ninth rib were clearly seen on omographic slices (Fig. 2A). The other two increased radiopharaceutical uptakes in the chest on planar images were matched ith the non-calcified paranchymal nodules in the inferior lobe f the left lung and middle lung lobe (Fig. 2B). These nodules also howed mild to moderate FDG uptake on the sequential restagng PET/CT (Fig. 3). These lung nodules could not be biopsied due o the patients’ advanced age and accompanying comorbidities. ince no other pathological FDG uptake that could explain the levated tumor markers was seen on the PET/CT, these nodules ere regarded as metastases of primary breast cancer. Although isualization of primary or metastatic tumors of the lung (e.g., steosarcoma, Ewing sarcoma, neuroblastoma, etc.) during routine one scintigraphy was described before, MDP avid lung metasasis of breast cancer has not been reported yet.1,2 The most ommon causes of accumulation of bone seeking radiopharmaceuicals in extraskeletal tissues include dystrophic and/or metastatic alcification, increased ectopic osteoblastic activity, metastases rom bone-forming primary tumors, increase of calcium-binding