99mTc-PYP and 68Ga-FAPI PET/CT Images of Hereditary Transthyretin Amyloidosis With Cardiac Involvement.

ABSTRACT: Amyloidosis is a protein misfolding disorder characterized by the extracellular deposition of insoluble amyloid fibrils, derived from abnormally folded proteins. These fibrils disrupt tissue structure and function, leading to organ dysfunction. The condition encompasses various subtypes, each associated with distinct precursor proteins and clinical manifestations. 99mTc-PYP scintigraphy is used widely and holds significant importance for diagnosis. 68Ga-FAPI is also a promising radiotracer for various diseases. To our knowledge, this is the first case of a patient with hereditary transthyretin amyloidosis with cardiac involvement, which FAPI PET showed diffuse increased myocardial uptake.

US-guided percutaneous ablation of thyroid nodules with 177LU-MAA (LUTMA) - Feasibility study.

PURPOSE: The main purpose is to evaluate the safety, and efficacy of 177Lutetium labeled macroaggregated albumin (LUTMA) ablation of thyroid nodules. MATERIALS AND METHODS: Patients with confirmed benign nodules who were not candidate or did not accept surgery were enrolled. Under ultrasonography (USG) guidance, LUTMA which was produced in our department, was administered into the nodules. Nodule volumes were assessed via USG before the injection and at 1-week, 1-month, and 3-months post-treatment. We calculated the volume reduction rates (VRRs) for these intervals. To detect extranodular activity leakage, patients underwent SPECT/CT imaging at one hour, 24 h, and one week post-injection. RESULTS: Fifteen patients (male: 12, female: 3) with benign thyroid nodules were eligible to join this study. These nodules were categorized as cystic (n = 9), solid (n = 3), or mixed (n = 3). Median nodules volume was 6.59 ml (range: 0.56-55 ml). Predicted absorbed dosee to the nodules varied between 10-1036 Gy. The VRRs at 3 months was 85% for all nodule types with gradual increases over time: 0%-92%, 20%-97%, and 28%-98% at 1 week, 1 month, and 3-months, respectively. The median VRR of cystic nodules was 89% (range: 81%-98%) at 3-months. It is significantly higher than solid ones (P = .009). None of the patients experienced adverse reactions or discomfort during the injection or follow-up. CONCLUSION: LUTMA treatment significantly reduces the volume of benign thyroid nodules, offering relief from disease-associated symptoms and cosmetic concerns. It emerges as a promising alternative to surgical and other local treatments for benign thyroid nodule ablation. CLINICAL SIGNIFICATION: LUTMA is a novel theranostic radiopharmaceutical which is promising in local ablative treatment of benign thyroid nodules.

Synchronous occurrence of medullary and papillary thyroid cancer and survival rates.

PURPOSE: Concurrence of medullary and papillary thyroid carcinoma (MTC and PTC) represents less than 1% of all thyroid malignancies. We aimed to reveal the demographic and clinical characteristics of this rare pathology and to evaluate the effect of the same or contralateral lobular localization of these two malignancies in clinical and laboratory features. Evaluation of progression-free survival (PFS) in current pathology is one of the important features of our study. METHODS: All patients diagnosed with simultaneous MTC and PTC after thyroidectomy were evaluated retrospectively. Data on the following variables were recorded: age, gender, tumor localization (ipsilateral lobe located MTC and PTC-Group I, contralateral lobe located MTC and PTC-Group II), tumor size, cervical lymph node metastasis, distant metastasis, tumor stage, postoperative basal calcitonin, carcinoembryonic antigen, thyroglobulin (Tg), and anti-Tg values. In all our cases, since MTC progressed before PTC, progression was accepted as serum calcitonin values exceeded 150 pg/mL. RESULTS: Groups were formed as follows: Group I, four cases where MTC and PTC were localized in different foci in the same lobe; Group II, nine cases where they were localized in different lobes. There was only one case in which two tumors were located in the same focus. The case with dual differentiation was included in Group I (35. 7%). When the PFS of the two groups were compared, no statistically significant difference was found ( P = 0.87). CONCLUSIONS: As a result of this analysis, the location of the simultaneously detected PTC in the same or different lobes with the MTC does not make a significant difference in clinical and laboratory features.

Hybrid Ga-68 prostate-specific membrane antigen PET/MRI in the detection of skeletal metastasis in patients with newly diagnosed prostate cancer: Contribution of each part to the diagnostic performance.

PURPOSE: Bone metastasis is essential in patients with prostate cancer (PCa) as it determines prognosis and survival. Hybrid PET/MRI allows simultaneous acquisition of PET and MRI data, thus combining the strength of both technologies allows the detection of bone marrow metastases that are missed by PET/CT. In this retrospective study, we aimed to evaluate the diagnostic efficiency of hybrid PET/MRI with Ga-68 prostate-specific membrane antigen (PSMA) in detecting skeletal metastases in newly diagnosed PCa patients and compared the effectiveness of stand-alone PSMA PET reviewing versus stand-alone whole-body (WB) MRI evaluation. We also investigated the effect of the interpretation of all PET/MR data together on clinical management. METHODS: We studied 74 newly diagnosed PCa patients who underwent PSMA PET/MRI for staging purposes. At first, PET and MRI were evaluated separately for bone lesions on a patient-and-lesion basis and then a further joint PSMA PET/MRI interpretation was made. RESULTS: Patient-based sensitivity, specificity, positive predictive value, negative predictive value and accuracy analysis for bone metastasis was, respectively, 1.0, 0.83, 0.54, 1.0, 0.86 for PET; 0.75, 0.96, 0.81, 0.95, 0.93 for WB MRI and 0.91, 0.95, 0.78, 0,98, 0.94 for PET/MRI. The combined PET/MRI evaluation changed the clinical impact in 13.5% of patients (eight correct and two wrong decisions) compared to PET stand-alone interpretation. CONCLUSION: PSMA PET imaging showed superior sensitivity to WB MRI in detecting bone metastases in newly diagnosed PCa patients, whereas WB MRI has superior specificity and PPV. Furthermore, the specificity and PPV of joint PET/MRI evaluation are better than PSMA PET alone. Despite the longer acquisition period, adding WB MRI sequences to PSMA PET imaging appears beneficial for PCa patient management.

Investigation of the ongoing pulmonary defects with perfusion-single photon emission computed tomography/computed tomography in patients under anticoagulant therapy for coronavirus disease 2019-induced pulmonary embolism.

OBJECTIVE: It was aimed to reveal the continuing perfusion defect rates in patients with a diagnosis of pulmonary embolism (PE) due to COVID-19 who have completed the third month of anticoagulant therapy but whose symptoms or laboratory elevations continue. METHODS: Patients with COVID-19 who were diagnosed with PE by Q-SPECT-CT between 1 September 2020 and 1 November 2021, who underwent control Q-SPECT/CT were included in the study. Demographic characteristics, laboratory findings, and first and second Q-SPECT/CT evaluation results of the patients were recorded. RESULTS: It was observed that the pulmonary defect continued in Q-SPECT/CT in the third month of anticoagulant treatment in 58.3% of the patients diagnosed with PE due to COVID-19, and new defects developed in 6.3%. The persistence rate of segment defects was higher than that of subsegment defects. It was observed that the defects persisted more frequently in patients with a history of hospitalization due to COVID-19. CONCLUSION: Perfusion defects may still be present in patients diagnosed with PE due to COVID-19 in the presence of persistent dyspnea/chest pain/D-dimer elevation after 3 months of treatment. Perfusion defect persistence rates are higher in defects more proximal to the subsegment level and in people with severe COVID-19, and extended treatment should be considered in these patients.

Diagnostic Performance of 99mTc-Methoxy-Isobuty-Isonitrile (MIBI) for Risk Stratification of Hypofunctioning Thyroid Nodules: A European Multicenter Study.

99mTc-MIBI (MIBI) imaging is able to exclude malignancy of hypofunctioning thyroid nodules (TNs) with high probability but false positive results are frequent due to low specificity. Therefore, pre-test selection of appropriate TNs is crucial. For image evaluation visual and semiquantitative methods (Washout index, WOInd) are used. Aim of this study was to evaluate the diagnostic performance of MIBI imaging in hypofunctioning TNs with indeterminate fine-needle aspiration cytology results in a multicentric European setting. Patients with hypofunctioning TNs, EU-TIRADS 4 or 5, Bethesda III/IV and MIBI imaging were included. For visual evaluation the intensity of MIBI uptake in the TN was compared to normal thyroid tissue. 358 patients with 365 TNs (n = 68 malignant) were included. Planar imaging (SPECT) showed a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 96% (94%), 21% (22%), 22% (15%), 96% (96%), and 35% (32%). The WOInd (38.9% of all cases, optimal cutoff: -19%) showed a sens 100% (spec 89%, PPV 82%, NPV 100%, ACC 93%). For hypofunctioning TNs at intermediate or high risk with indeterminate cytology, a MIBI negative result on visual evaluation is an effective tool to rule-out thyroid malignancy. The semi-quantitative method could considerably improve overall diagnostic performance of MIBI imaging.

Investigation of perfusion defects by Q-SPECT/CT in patients with mild-to-moderate course of COVID-19 and low clinical probability for pulmonary embolism.

OBJECTIVE: Pulmonary embolism is a severe source of mortality and morbidity in patients with severe and critical coronavirus disease 2019. It is not yet clear whether the tendency to thrombosis is increased in the mild-to-moderate course of COVID-19. Our research aims to show the clinical benefit of Q-SPECT/CT in diagnosing PD in outpatients treated with mild-to-moderate course of COVID-19 and to determine the frequency of perfusion defects in these patients having relatively lower risk. METHODS: All patients who underwent Q-SPECT/CT with suspicion of embolism were examined retrospectively. Only patients with low clinical probability and mild-to-moderate course of COVID-19 for PE were included in the study. The patients were evaluated comparatively as those with and without perfusion defects. Patients were divided into laboratory suspicion, clinical suspicion, or clinical and laboratory suspicion. RESULTS: In outpatients with mild-to-moderate COVID-19 with low clinical probability for PE, PD without CT abnormality was detected with a rate of 36.6% with Q-SPECT/CT performed for complaints of high D-dimer and/or dyspnea. None of the patients had PD at more proximal level than the segment level. PD with no concomitant CT abnormality was observed with a rate of 56.5% in patients with both clinical and laboratory suspicion. For D-dimer = 0.5 mg/dL cut-off sensitivity is 85%, for D-dimer = 1.5 mg/dL cut-off specificity 81%. CONCLUSION: Thrombosis tendency is also present in outpatients with mild-to-moderate COVID-19, and these patients should also be offered anticoagulant prophylaxis during the COVID-19 period.

Comparison of brain F-18 FDG PET/MRI with PET/CT imaging in pediatric patients.

BACKGROUND: Standardized uptake values (SUVs) are important indexes for evaluating the accuracy of disease diagnoses achieved via fluoro-18 deoxyglucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) and positron emission tomography/magnetic resonance imaging (PET/MRI). The purpose of this study is to describe normal cerebral FDG uptake in the pediatric population and compare SUVmax/mean results for brain images obtained from PET/CT and PET/MRI in neurologically healthy pediatric examinees. METHODS: This study included 20 patients who were < 18 years of age and were without intracranial malignancy and/or brain disorders. Patients underwent either PET/CT imaging (n = 10) or PET/MRI imaging (n = 10) after 70-80 min of F-18 FDG injection. The SUVmax and SUVmean for various brain regions were calculated and compared between sides and imaging modalities using with appropriate statistical tests. RESULTS: The median SUVmax/SUVmean values of the right-sided frontal, parietal, temporal, and occipital lobes were 8.63/ 6.18, 8.85 / 6.97, 6.88 / 4.99, and 11.06 / 7.02 in PET/CT, respectively, and 11.45 / 8.59, 10.16 / 8.47, 8.82 / 6.6, and 11.71 / 8.25 in PET/MRI, respectively. The median SUVmax/SUVmean values of the left-sided frontal, parietal, temporal, and occipital lobes were 9.05 / 6.86, 8.03 / 6.62, 6.49 / 4.77, and 10.6 / 7.73 in PET/CT, respectively, and 10.7 / 8.16, 11.06 / 7.88, 8.13 / 6.09, and 10.96 / 9.22 in PET/MRI, respectively. CONCLUSIONS: These results showed that there was no statistically significant difference in SUVs values between the two brain imaging modalities except from SUVmax value of left-sided parietal lobe and no asymmetric radiopharmaceutical uptake between the left and right brain regions or cerebellums in each modality, suggested that in brain imaging, PET/MRI can be used reliably instead of PET/CT.

Evaluation of F-18 DOPA PET/CT in the detection of recurrent or metastatic medullary thyroid carcinoma: comparison with GA-68 DOTA-TATE PET/CT.

OBJECTIVE: PET imaging with F-18 DOPA (FDOPA) and Ga-68 DOTATATE (TATE) shows the most promising results to detect medullary thyroid cancer (MTC) recurrence. We performed this comparative study to detect the site of recurrent or metastatic disease in MTC patients with elevated serum calcitonin (Ctn) and/or carcinoembryonic antigen (CEA) levels. METHODS: We studied 46 MTC patients (25 women, 21 men) with elevated Ctn and/or CEA levels during follow-up who had both FDOPA and TATE PET/CT scans for re-staging purposes. RESULTS: FDOPA PET imaging yielded an overall sensitivity of 86.8%, specificity of 100%, PPV of 100%, NPV of 61.5%, and accuracy of 89.1%, while TATE PET scan had the same values as 84.2%, 87.5%, 96.9%, 53.8%, and 84.6%, respectively, and there was no statistically significant difference between the two modalities with the exception of the specificity value that was higher for FDOPA imaging. In a subgroup of patients with overt Ctn or CEA elevation, sensitivity of FDOPA increased significantly, whereas TATE sensitivity did not change. FDOPA PET imaging was significantly superior in detecting liver and regional lymph node (LN) metastases, while TATE PET scan was significantly better in the skeletal metastases. Early FDOPA demonstrated 11 invisible lesions on late FDOPA. CONCLUSION: Both FDOPA and TATE PET/CT imaging are useful to localize recurrences in MTC patients. While TATE imaging is superior to reveal skeletal disease, FDOPA seems better in liver and regional LN metastases; therefore, the two modalities appear complementary in monitoring MTC patients with elevated serum Ctn and/or CEA levels.

The role of 68Ga-DOTATATE PET/CT and 18F-FDG PET/CT in the follow-up of patients with medullary thyroid cancer.

OBJECTIVE: Medullary thyroid cancer (MTC) is an aggressive form of thyroid malignancy with local metastasis in 30%-50% of the cases and distant metastasis predominantly to lung, liver and skeleton in 13%-15% of patients. Identification of the lesion using imaging modalities is of crucial importance for disease management in the recurrent or metastatic MTC. In this study, we aimed to determine the efficacy of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) and gallium-68 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid tyrosine-3-octreotate (68Ga-DOTATATE) PET/CT imaging in patients with MTC and to evaluate the relationship between imaging findings and serum tumor markers. MATERIALS AND METHODS: The records of MTC patients, who were treated and followed-up in our department between the years 2005 and 2018 were retrospectively analyzed. Seventy-three patients with MTC, who underwent either 68Ga-DOTATATE PET/CT (n=61) and/or 18F-FDG PET/CT (n=59) together with serum calcitonin (Ctn) and/or carcinoembryogenic antigen (CEA) measurement within 6 months period were included in the study. Gallium-68-DOTATATE PET/CT and 18F-FDG PET/CT scans performed within 6 months on the same patient (n=38) were analyzed separately for comparison of the efficacy of both modalities. RESULTS: The overall sensitivity of 18F-FDG PET/CT and 68Ga-DOTATATE PET/CT were 72.4% and 88.1%, respectively in detecting recurrent or metastatic disease. In the group of patients, who had both 18F-FDG PET/CT and 68Ga-DOTATATE PET/CT within 6 months interval (median: 1.14 months; range: 0.03 - 5.7 months), no significant difference was found in the overall sensitivity of both imaging modalities, however 68Ga-DOTATATE PET/CT was found to be more sensitive in detection of bone lesions compared to 18F-FDG PET/CT (P=0.005). CONCLUSION: Both 18F-FDG PET/CT and 68Ga-DOTATATE PET/CT are efficient imaging modalities in detection of recurrent or metastatic disease in MTC patients. Gallium-68-DOTATATE PET/CT could be more beneficial in detection of bone metastases with respect to 18F-FDG PET/CT.

The impact of different computational assumptions in 131 I dosimetry for hyperthyroidism therapy.

PURPOSE: The goal of the current study was to investigate the impact of different computational models on 131 I dosimetry prior to hyperthyroidism therapy. It was also aimed to highlight an accurate and cost-effective method for routine dosimetry of graves and toxic adenoma patients. METHODS: A cohort of 45 patients was recruited in the current study with Graves (n = 30) and Toxic Adenoma (n = 15) diseases. The eligibility criterion was determined using the patients' blood test, 99m Tc- pertechnetate scintigraphy, and ultrasound scan. A properly calibrated thyroid probe equipped with sodium iodide crystal [NaI(Tl)] was used to obtain the uptake measurements at 2, 24, 48, 72, and 96 h following administration of 0.27-0.73 MBq 131 I tracer. The absorbed radiation dose of the thyroid gland/nodule was calculated by three different methods. The calculation models were based on the time-integrated activity (recommended by MIRD), effective half-life (recommended by EANM), and ellipsoidal-shape assumption. RESULTS: The mean effective half-life was 138 ± 41 h and 110 ± 48 h in Graves and Toxic Adenoma patients, respectively. The mean residence time was 125 ± 5 h in Graves patients, while it was 93 ± 55 h in Toxic Adenoma. The amount of 131 I activity required to deliver 200 Gy to the thyroid gland in Graves patients was calculated as 436 ± 381 MBq, 426 ± 370 MBq, and 488 ± 455 MBq according to MIRD, EANM, and ellipsoidal-shape model, respectively. However, the activity required to impart 300 Gy in the toxic nodules was computed as 622 ± 332 MBq by MIRD, 907 ± 588 MBq by EANM, and 1060 ± 639 MBq by the ellipsoidal-shape model. Overall, no significant difference was found between the MIRD and both of the EANM and ellipsoidal-shape models in the Graves patients (R2  = 0.99, P > 0.05). In contrast, less agreement (R2  = 0.86) was shown between EANM and MIRD in Toxic Adenoma patients with no statistically significant difference (P > 0.05), while the difference was significant (Pvalue  < 0.05) between the MIRD and the ellipsoidal-shape model with moderate association (R2  = 0.66). CONCLUSION: It was deduced that the effective half-life-based model (EANM model) is a successful and affordable method for performing dosimetry in Graves patients. While, unit density sphere model sounds the most appropriate approach to be used in Toxic Adenoma dosimetry. However, using the ellipsoidal-shape assumption in the thyroid gland/or nodule dose calculation leads to redundantly larger activity administration.

The contribution of SPECT/CT in patients with radionuclide shuntography through shunt dysfunction.

OBJECTIVE: Radionuclide CSF study is a simple, effective, and low-radiation-dose procedure for the assessment of shunt patency. With the help of CT image of single-photon emission computed tomography/computed tomography (SPECT/CT), the interpretation becomes more accurate and easier.The aim of this study was to compare the classical methods and 2D planar scintigraphic images with radionuclide shuntography fused SPECT/CT. METHODS: Between 2015-2019 all hydrocephalic patients who underwent radionuclide shuntography and classical methods (cranial CT, USG and/or direct X-rays), for suspected VP shunt malfunction at our hospital were retrospectively enrolled in the study. Fusion with SPECT/CT is provided in all radionuclide shuntographies. Approximately 0.5-1 mCi diethylene-triaminepentaaceticacid (DTPA) was intrathecally injected. Images were collected as 5-second frames for the first minute, and 1-min frames for the second to the 30th min. Static whole body images were obtained as early (30 min) and delayed (120 min) images. SPECT/CT was performed in 120 min. RESULTS: When the classical methods were evaluated in the operated patients, according to the direct radiographic findings, in only 17 patients had shunt dysfunction due to disconnection-kinking or laceration, was obtained.On the other hand,while67 shuntography were evaluated,65 of these patients (97%) whose intraoperative and shuntography findings were found to be compatible with each other. CONCLUSION: The 3D SPECT images combined with the two-dimensional planar images added to the CT provide more accurate information and also provide detailed anatomical information. The patient's operation was performed successfully in one session in cooperation with the other surgical branches when needed.

Thyroid uptake test with portable device (COTI) after 131I tracer administration: proof of concept.

COTI (collar therapy indicator) has been recently introduced for the detection of gamma rays with emphasis on thyroid investigations. The aim of this study was to test the feasibility of a prototype version of COTI including activity detectors with low sensitivity in performing thyroid uptake measurements for a large group of patients. Consequently, thyroid uptake tests were carried out for a total of 89 patients (22 males and 67 females; age: 44 ± 13 years) with thyroid cancer (n = 74), hyperthyroidism (n = 16) at 2 and 24 h after administration of 0.44-2 MBq of 131I. Eight individuals among the thyroid cancer patients were monitored up to 96 h after administration. The COTI device was equipped with two CsI (Tl) detectors, known as LoHi type, sensitive to activity ranges from 0.02 to 30 MBq of 131I. The uptake values from COTI were compared with those measured with a standard probe. It was found that the mean uptake of thyroid activity in thyroid cancer patients was 2.1 ± 1.3% at 2 h when measured with the standard probe, while it was 2.2 ± 1.2% when measured with COTI. In addition, the average uptake at 24 h after administration was 2.5 ± 3.2% and 3.2 ± 3.8% measured with COTI and the standard probe, respectively. A strong correlation was found at 24 h between the results obtained with COTI and the standard probe, while a weaker correlation was seen at 2 h. Overall, there was no significant difference between the results obtained with the standard probe and those obtained with COTI at both 2 and 24 h (Pvalue ≥ 0.05). Besides, 85% of the uptake values measured with COTI were less than those measured with the standard probe at the 24 h after administration. The average uptake value was 0.9 ± 0.8% after 96 h by COTI, and 1.4 ± 1.3% by the standard probe. Pertaining to the hyperthyroidism patients, COTI showed mean uptake values of 20 ± 16% and 23 ± 18% at 2 and 24 h, respectively. In contrast, the standard probe suggested higher mean uptake values of 26 ± 18% and 30 ± 22%, respectively. It is concluded that the prototype of COTI used in the present study has been proved to be a feasible and promising tool in thyroid investigations. It is noted, however, that the next COTI generation should include detectors equipped with collimator and energy discrimination.

Complete response after ceritinib treatment in non-small cell lung cancer in an elderly patient.

INTRODUCTION: Ceritinib is a selective second-generation ALK inhibitor that is highly sensitive to echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) molecule. CASE REPORT: In this paper, we report a 68-year-old female that was diagnosed with stage 4 ALK-positive non-small cell lung cancer (NSCLC).Management and outcome: She was treated with crizotinib first-line, cisplatin and gemcitabine as second-line. And for third-line, ceritinib was started. She had complete response over 3.5 years under ceritinib treatment. And she is still receiving ceritinib with no adverse event. DISCUSSION: Cases achieving complete response with ceritinib treatment are rare. In this paper, we aimed to emphasize the complete response in stage 4 NSCLC in an elderly patient.

Performance of F-18 Fluorocholine PET/CT for Detection of Hyperfunctioning Parathyroid Tissue in Patients with Elevated Parathyroid Hormone Levels and Negative or Discrepant Results in conventional Imaging.

OBJECTIVE: Our aim was to assess the diagnostic performance of F-18 fluorocholine (FCH) positron emission tomography/computed tomography (PET/CT) in detecting hyperfunctioning parathyroid tissue (HPT) in patients with elevated parathyroid hormone levels with negative or inconclusive conventional imaging results and to compare the findings with those obtained using technetium-99m sestamibi (MIBI) scintigraphy and neck ultrasonography (US). MATERIALS AND METHODS: Images of 105 patients with hyperparathyroidism who underwent FCH PET/CT, dual-phase MIBI parathyroid scintigraphy (median interval: 42 days), and neck US were retrospectively analyzed. The gold standard was histopathological findings for 81 patients who underwent parathyroidectomy and clinical follow-up findings in the remaining 24 patients. Sensitivities, positive predictive values (PPVs), and accuracies were calculated for all imaging modalities. RESULTS: Among the 81 patients who underwent parathyroidectomy, either parathyroid adenoma (n = 64), hyperplasia (n = 9), neoplasia (n = 4), or both parathyroid adenoma and hyperplasia (n = 1) were detected, except 3 patients who did not show HPT. Of the 24 (23%) patients who were followed-up without operation, 22 (92%) showed persistent hyperparathyroidism. FCH PET/CT showed significantly higher sensitivity than MIBI scintigraphy and US in detection of HPT (p < 0.01). Sensitivity, PPV, and accuracy of FCH PET/CT were 94.1% (95/101), 97.9% (95/97), and 92.4% (97/105), respectively. The corresponding values for MIBI scintigraphy and US were 45.1% (46/102), 97.9% (46/47), and 45.7% (48/105) and 44.1% (45/102), 93.8% (45/48), and 42.9% (45/105), respectively. Among the 35 patients showing negative MIBI scintigraphy and neck US findings, 30 (86%) showed positive results on FCH PET/CT. FCH PET/CT could demonstrate ectopic locations of HPT in 11 patients whereas MIBI and US showed positive findings in only 6 and 3 patients, respectively. CONCLUSION: FCH PET/CT is an effective imaging modality for detection of HPT with the highest sensitivity among the available imaging techniques. Therefore, FCH PET/CT can be recommended especially for patients who show negative or inconclusive results on conventional imaging.

177Lu-Labeled Macroaggregated Albumin Imaging and Treatment Effect in Patient with Cystic Thyroid Nodule.

A number of different peptides or antibodies have been labeled with 177Lu and used for clinical imaging and treatment. To our knowledge, 177Lu had never before been used to label macroaggregated albumin, and our radiopharmacy laboratory at Istanbul University-Cerrahpasa made a special effort to do so. We present the case of a 43-y-old man whose cystic thyroid nodule was treated with an intranodular injection of 177Lu-macroaggregated albumin and imaged with SPECT/CT.

Prognostic value of ADC measurements in predicting overall survival in patients undergoing 90Y radioembolization for colorectal cancer liver metastases.

AIM: To assess the ability of diffusion-weighted imaging (DWI) in predicting the overall survival in patients who underwent Yttrium 90 radioembolization (90Y-RE) for colorectal liver metastases (CLM) with other well-established clinical and imaging parameters by comparing the pre- and post-treatment apparent diffusion coefficient (ADC) values of the lesions. METHODS: A total of 81 metastatic lesions of 27 consecutive patients who underwent DWI before and after the 90Y-RE session were enrolled in the study. ADC values were calculated from the entire (ADCe) and peripheral (ADCp) tumor on pre- and post-treatment DWI, and any relative increase in ADC >0% accepted as a functional imaging response. The impact of functional imaging response in addition to other well-known parameters including Response Evaluation Criteria in Solid Tumors (RECIST), hepatic tumor burden, Eastern Cooperative Oncology Group performance status (ECOG-PS) and the presence of extrahepatic metastases in predicting overall survival (OS) was assessed using Kaplan-Meier curves and Cox-regression analyses. RESULTS: The median OS of the patients was 10 months (range, 6-20 months) while the median OS of the responders being significantly longer than the non-responders for ADCe and ADCp (median 11 vs 7 months, P = 0.003; median 12 vs. 7 months, P < 0.0001, respectively). The RECIST score was also significantly affected the OS (progressive or stable disease median 8 months vs. partial response 15 indent months, P = 0.019). The other parameters including hepatic tumor burden, gender, ECOG score, the involvement of the liver lobes, and the presence of extrahepatic metastases were not associated with the OS. In multivariate analysis, only ADCp remained as an independent predictor of OS (P = 0.003, HR = 19.878). CONCLUSION: Any increase in relative ADCp or ADCe values after Y90-RE treatment was associated with longer OS in CLM patients, and DWI seems to be valuable imaging biomarker in predicting OS in CLM patients during the early post-interventional period after 90Y-RE.