Radioguided surgery of thyroid carcinoma recurrences: the role of preoperative (99m)Tc-labeled human serum albumin macroaggregates-SPECT/CT mapping.

Reoperative surgery in the neck for recurrent differentiated thyroid cancer (DTC) is associated with increased morbidity compared with primary surgery. Radioguided occult lesion localization was recently proposed in patients with DTC recurrences. Here we report on the combination of radioguided occult lesion localization procedure to preoperative SPECT/CT in 2 patients with DTC recurrences. This combination was proved to be simple and technically feasible. Addition of SPECT/CT to conventional preoperative planar scans provided an accurate 3-dimensional road map for neck exploration.

18F-FDG uptake changes in liver and mediastinum during chemotherapy in patients with diffuse large B-cell lymphoma.

PURPOSE: The main objective of this study was to assess the intrasubject and intersubjects variability of 18F-FDG uptake in liver (LIV) and mediastinum (MBP) among patients with diffuse large B-cell lymphoma (DLBCL), treated with different chemotherapy regimens. PATIENTS AND METHODS: Fifty patients with DLBCL who underwent 18F-FDG PET/CT scan at baseline, after a few cycles of therapy (interim PET) and on completion of therapy (final PET), were enrolled retrospectively. SUVmean and SUVmax values for LIV and MBP, their differences (LIV - MBP SUVmean and LIV - MBP SUVmax), and their changes were calculated, respectively. RESULTS: Liver uptake significantly increased in the interim in comparison with baseline and final PET, respectively, whereas MBP activity remained stable during chemotherapy. The intersubject variability of 18F-FDG uptake in LIV and MBP ranged from 20.2% to 25.4%. CONCLUSIONS: The variability of the LIV uptake during chemotherapy should be taken into account when this parameter is used to score the interim PET scan and to make decisions in defining response-adapted therapeutic strategies. Vice versa, the stability of MBP activity during therapy provides a more reliable benchmark for the response assessment.Finally, the intersubjects variability of both parameters should be considered when the visual evaluation of the interim PET is performed by point score models.

Relationship between serum thyroglobulin and 18FDG-PET/CT in 131I-negative differentiated thyroid carcinomas.

BACKGROUND: The purpose of this study was to assess the relationship between [(18) F]-fluorodeoxyglucose ((18) FDG)-positron emission tomography/CT ((18) FDG-PET/CT) and serum thyroglobulin (Tg) in patients with recurrent differentiated thyroid carcinoma (DTC). METHODS: Forty-two patients with recurrent DTC and negative Tg antibodies were included in the study. All patients underwent (131) I therapy due to an increasing serum Tg with a corresponding negative (131) I posttreatment whole body scan. The (18) FDG-PET/CT scans were then performed on all patients, serum Tg was measured concurrently, and respective results were compared. RESULTS: Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy of the (18) FDG-PET/CT examination were 93%, 84%, 93%, 84%, and 90%, respectively. The sensitivity of (18) FDG-PET/CT significantly increased in patients with serum Tg levels ≥4.6 ng/mL (96%) in comparison with patients having lower levels (25%; p < .001). Nonetheless, 3 of 27 patients (11%) with a true-positive (18) FDG-PET/CT still had a Tg <4.6 ng/mL. CONCLUSION: Although (18) FDG-PET/CT scans are more likely to be positive with pretest Tg levels ≥4.6 ng/mL, 11% of patients with DTC with a lower serum Tg level will still have a positive scan. Our findings are in contrast with the American Thyroid Association (ATA) guidelines, which only recommend to perform (18) FDG-PET/CT in patients with Tg levels >10 ng/mL.

Multi-field-of-view SPECT is superior to whole-body scanning for assessing metastatic bone disease in patients with prostate cancer.

AIM: The aim of this study was to compare the diagnostic performance of whole-body bone scintigraphy (WBS) and multi-field-of-view single photon emission tomography (multi-FOV SPECT) with 99mTc-oxidronate (99mTc-HDP) in patients with prostate cancer (PCa). METHODS: In a prospective study, WBS and SPECT acquisitions were performed in 194 patients with histologically confirmed PCa and serum prostate-specific antigen (PSA) levels above 10 ng/mL. Scans obtained using the two modalities were interpreted separately. Clinical and biochemical follow-up, radiological studies and biopsies served as benchmarks for the assessments. The impact of PSA level on WBS and SPECT results was also evaluated. RESULTS: The patient-based sensitivity, specificity, accuracy, PPV and NPV values of SPECT examinations were higher than those of WBS, especially in patients with serum PSA levels <40 ng/mL. CONCLUSION: Multi-FOV SPECT proved to be more sensitive and specific than WBS in detecting bone metastases in PCa patients.

Thyroid remnant estimation by Tc-99m-sestamibi scanning predicts the effectiveness of rhTSH-stimulated I-131 ablation in patients with differentiated thyroid carcinoma.

AIM: To evaluate the relationship between postsurgical cervical Tc-99m-sestamibi scan uptake and the rate of successful remnant ablation after recombinant human-thyrotropin (rhTSH)-aided-I-131 ablation in patients with differentiated thyroid carcinoma (DTC). METHODS: In all, 154 DTC patients who underwent total thyroidectomy and rhTSH-aided remnant ablation with I-131 (3.7 GBq) were enrolled. Tc-99m-sestamibi scans were performed during continuing thyroid hormone administration in all cases. Thyroid ablation was assessed after 6 to 12 months by rhTSH-stimulated I-131-whole-body scan and thyroglobulin measurement. The rate of successful ablation, occurrence of radioiodine-induced thyroiditis, and length of hospitalization were correlated with the Tc-99m-sestamibi scintigraphy results. RESULTS: Tc-99m-sestamibi uptake was significantly lower in ablated versus nonablated patients (P<0.0001). A visually positive scan and a Tc-99m-sestamibi uptake greater than 0.9% predicted a high-risk of unsuccessful ablation, prolonged hospitalization, and the occurrence of radioiodine-induced thyroiditis. CONCLUSIONS: Tc-99m-sestamibi scintigraphy is a simple and feasible tool to evaluate thyroid remnants and to predict radioiodine ablation results in patients with DTC.

Lymph node thyroglobulin measurement in diagnosis of neck metastases of differentiated thyroid carcinoma.

Aim. Enlarged cervical lymph nodes (LNs) in patients with thyroid cancer are usually assessed by fine-needle aspiration cytology (FNAC). Thyroglobulin (Tg) is frequently elevated in malignant FNAC needle wash specimens (FNAC-Tg). The objectives of the study were to (1) determine an appropriate diagnostic cut-off for FNAC-Tg levels (2) compare FNAC and FNAC-Tg results in a group of 108 patients affected by differentiated thyroid carcinoma (DTC). Methods. A total of 126 consecutive FNACs were performed on enlarged LNs and the final diagnosis was confirmed by surgical pathology examination or clinical follow-up. The best FNAC-Tg cut-off level was selected by receiver operating curve analysis, and diagnostic performances of FNAC and FNAC-Tg were compared. Results. The rate of FNAC samples adequate for cytological examination was 77% in contrast FNAC-Tg available in 100% of aspirates (P < .01). The sensitivity, specificity, and accuracy of FNAC were 71%, 80%, 74%, 100%, 80%, and 94%, respectively. The most appropriate cut-off value for the diagnosis of thyroid cancer metastatic LN was 1.1 ng/mL (sensitivity 100%, specificity 100%). Conclusions. The diagnostic performance of needle washout FNAC-Tg measurement with a cut-off of 1.1 ng/mL compared favorably with cytology in detecting DTC node metastases.

Could different hydration protocols affect the quality of 18F-FDG PET/CT images?

UNLABELLED: In a group of oncologic patients undergoing (18)F-FDG PET/CT, we compared 4 different protocols of hydration to investigate their impact on image quality and to choose the best practice. METHODS: One hundred twenty subjects undergoing (18)F-FDG PET/CT were randomized into 4 groups: group A, receiving free oral hydration; group B, receiving an intravenous injection of 10 mg of furosemide and infusion of 500 mL of saline solution starting 5 min after tracer injection; group C, receiving oral hydration with 500 mL of water; and group D, receiving intravenous injection of 10 mg of furosemide and infusion of 250 mL of the saline solution starting 30 min after the (18)F-FDG injection. The maximum standardized uptake value of muscular and adipose tissues, blood pool (aortic and left ventricular cavity), bladder, and renal parenchyma was calculated for each subject. RESULTS: These 4 groups were comparable in age, body mass index, blood glucose level, and serum creatinine level. Group A showed the worst results. The controlled hydration protocols (groups B, C, and D) provided lower background activity in the soft tissues and lower urinary activity in the bladder and kidney without significant differences in blood activity. The administration of furosemide produces lower activity in the urinary tract without significant changes in (18)F-FDG distribution in the muscle, fat, or blood pool. The best results were in group D. CONCLUSION: Controlled hydration, particularly with standardized parenteral protocols, reduces the background activity in the soft tissues with the potential benefit of increasing the tumor-to-background contrast. Furosemide does not change tracer distribution in normal tissues but improves the quality of PET/CT images, reducing activity in the excretory system, particularly if the furosemide is administered late after (18)F-FDG injection.

18FDG-positron emission tomography/computed tomography (PET/CT) scanning in thyroid nodules with nondiagnostic cytology.

OBJECTIVE: To assess the role of positron emission tomography/computed tomography (PET/CT) scans with (18) FDG ((18)FDG-PET/CT) in the evaluation of thyroid nodules with nondiagnostic cytology. SUBJECTS AND METHODS: Eighty-eight patients with a single euthyroid nodule and repeatedly nondiagnostic ultrasound-guided fine-needle cytology (US-FNC) were enrolled in the present study. Nodules concentrating (18)FDG were considered positive (i.e. suspicious for malignancy). Histological findings were obtained after surgery in all patients. RESULTS: None of 41 patients with negative (18)FDG-PET/CT scan had a final histological diagnosis of malignancy (i.e. no false-negative results). Twenty-nine patients with final histological diagnosis of thyroid cancer had positive (18)FDG-PET/CT scan. Eighteen patients with final histological diagnosis of benign lesions (including four with follicular adenomas) also had positive (18)FDG-PET/CT scans. The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were 100%, 69%, 79%, 62% and 100%, respectively. CONCLUSIONS: A negative (18)FDG-PET/CT scan accurately excludes malignancy in thyroid nodules with non-diagnostic US-FNC procedures. Histology is still necessary to distinguish benign from malignant disease in (18)FDG-PET/CT-positive nodules, but unnecessary surgery could have been reduced from 88 to 41 cases (46%) in our series.

Undetectable thyroglobulin in patients with differentiated thyroid carcinoma and residual radioiodine uptake on a postablation whole-body scan.

AIM: To assess the impact of laboratory interferences and pitfalls in producing falsely undetectable Tg in differentiated thyroid carcinoma (DTC) patients with residual iodine-avid thyroid tissue on a posttreatment whole-body scan (PT-WBS). METHODS: From 298 consecutive patients with histologically proven DTC, 47 patients (16%) with undetectable serum Tg but residual ¹³¹I uptake on a PT-WBS were selected. Interferences from antithyroglobulin antibodies (TgAb), heterophile antibodies, and hook-effects were screened; in the remaining samples, serum Tg was measured in 3 different immunoassays. RESULTS: Of 47 patients, 11 (23%) showed interference from either thyroglobulin antibodies (n = 10) or heterophile antibodies (n = 1). Among the 36 remaining patients, 18 showed detectable Tg levels after retesting using a different immunoassay, whereas the remaining 18 patients also showed detectable Tg levels in a third Tg immunoassay. However, only 7 patients showed a detectable Tg in both secondarily used assays. Tg levels remained undetectable in all methods in 9 patients (19%) even after extensive laboratory work-up and despite the presence of ¹³¹I-avid tissue found in PT-WBS. CONCLUSIONS: A careful assessment of interferences in Tg measurement significantly reduced the occurrence of undetectable Tg among patients with ¹³¹I uptake in PT-WBS. However, such extensive assessment is difficult in clinical practice and one-fifth of patients still had undetectable Tg in multiple assays despite an intensive laboratory work-up. A benchmark between ¹³¹I imaging and Tg measurement authenticates the interpretation of Tg measurements and, consequently, remains of pivotal value by authenticating the use of serum Tg during further follow-up of DTC patients.

Evaluation of serum parathyroid hormone-related peptide in hyperthyroid patients.

BACKGROUND: Hypercalcemia occurs in 10-20% of patients with hyperthyroidism, but its pathogenesis is still unclear. AIM: To evaluate changes in parathyroid hormone-related peptide (PTH-rP) concentration in hyperthyroid patients compared with healthy controls. METHODS: We studied PTH-rP, parathormone (PTH) and ionized calcium levels in 153 hyperthyroid patients, and 89 control subjects. These variables were revaluated after attainment of euthyroidism with the antithyroid drug carbimazole for 6 months in a subgroup of 47 patients. RESULTS: Pretreatment PTH-rP and ionized calcium level were significantly higher in hyperthyroid patients than in controls, whereas an opposite trend occurred for PTH. All parameters normalized after carbimazole therapy. CONCLUSION: Untreated hyperthyroid patients exhibited a significant elevation in serum ionized calcium and PTH-rP and a significant reduction in serum PTH levels when compared with healthy controls. Our data favoured the hypothesis of a direct involvement of PTH-rP in the pathogenesis of hypercalcemia in hyperthyroid patients.

Spurious hypercalcitoninemia and heterophilic antibodies in patients with thyroid nodules.

BACKGROUND: The purpose of our study was to examine the prevalence of significant heterophilic antibody (HAb) interferences in serum calcitonin measurement in a large cohort of patients with thyroid nodules. METHODS: Enrolled in the study were 378 patients with thyroid nodules shown not to have medullary thyroid carcinoma (MTC) after extensive diagnostic workup. Serum calcitonin measurement was performed before and after incubating each serum sample in heterophilic-blocking tubes (HBTs) and the differences were calculated. Samples showing an absolute percentage difference greater than 3 SD from the mean percentage difference were considered as affected by heterophilic antibody interference. RESULTS: Five of 378 patients (1.3%) with HAb interferences were identified, 4 with clinically relevant false-positive calcitonin results. CONCLUSION: A false-positive calcitonin result due to HAb interference occurs more frequently than MTC (1.3% vs 0%) in our patient series. A serum pretreatment in HBTs should be considered when increased serum calcitonin levels are found in a patient with a thyroid nodule to prevent unwarranted investigations or therapies.

Postsurgical thyroid remnant estimation by (99m) Tc-pertechnetate scintigraphy predicts radioiodine ablation effectiveness in patients with differentiated thyroid carcinoma.

BACKGROUND: The purpose of this study was to evaluate the relationship between postsurgical neck (99m) technetium ((99m) Tc)-pertechnetate uptake and the rate of successful remnant ablation after radioiodine treatment in patients with differentiated thyroid carcinoma (DTC). METHODS: Retrospectively enrolled were 232 patients with DTC who underwent total thyroidectomy and fixed activity ablation with 3.7 GBq ¹³¹I. The (99m) Tc scans were performed on all patients before ¹³¹I administration. Thyroid ablation was assessed after 6 to 12 months by thyroid-stimulating hormone (TSH)-stimulated ¹³¹I-WBS and thyroglobulin measurement. The rate of successful ablation, occurrence of radioiodine-induced thyroiditis, and length of hospitalization were correlated with the (99m) Tc-pertechnetate scintigraphy results. RESULTS: A (99m) Tc uptake was significantly lower in ablated versus nonablated patients (p < .001). High (99m) Tc-pertechnetate uptake, especially greater than 1.4%, predicted a high-risk of unsuccessful ablation. Higher (99m) Tc-pertechnetate uptake was also related to prolonged hospitalization and the occurrence of radioiodine-induced thyroiditis. CONCLUSION: The (99m) Tc-pertechnetate scintigraphy is a simple and feasible tool to evaluate thyroid remnants and to predict radioiodine ablation results in patients with DTC.

Accessory spleen mimicking a pancreatic neuroendocrine tumor.

A 60-year-old man underwent computed tomography as part of colorectal cancer follow-up. A hypervascular nodule was found within the pancreatic tail and subsequently proved to be positive on [111In] DTPA-octreotide scan. A neuroendocrine tumor of the pancreas was supposed and a distal pancreatectomy performed. Heterotopic splenic tissue was finally proved by pathological examination. The present case suggests that intrapancreatic accessory spleen be considered in the differential diagnosis of pancreatic lesions positive on [111In] DTPA-octreotide scan.

Hyperfunctioning solid/trabecular follicular carcinoma of the thyroid gland.

A 68-year-old woman with solid/trabecular follicular thyroid carcinoma inside of an autonomously functioning thyroid nodule is described in this paper. The patient was referred to our clinic for swelling of the neck and an increased pulse rate. Ultrasonography showed a slightly hypoechoic nodule in the right lobe of the thyroid. Despite suppressed TSH levels, the (99m)Tc-pertechnetate scan showed a hot area corresponding to the nodule with a suppressed uptake in the remaining thyroid tissue. Histopathological examination of the nodule revealed a solid/trabecular follicular thyroid carcinoma. To the best of our knowledge, this is the first case of hyperfunctioning follicular solid/trabecular carcinoma reported in the literature. Even if a hyperfunctioning thyroid carcinoma is an extremely rare malignancy, careful management is recommended so that a malignancy will not be overlooked in the hot thyroid nodules.

Circulating procalcitonin in aseptic carcinoma patients: a specificity study with (18)F-fluorodeoxyglucose positron-emission tomography/computed tomography as benchmark.

BACKGROUND: The goal of the study was to evaluate the specificity of serum procalcitonin (PCT) in a large cohort of patients with solid carcinomas at different stages. METHODS: The study involved 447 patients having histologically confirmed carcinoma of the breast, head and neck, ovary, cervix or non-small cell lung carcinoma. Patients with a history of small cell lung cancer, neuroendocrine tumors, medullary thyroid carcinoma, sepsis, systemic inflammatory syndrome, renal failure and/or serum C-reactive protein above 5 ng/mL were excluded. Additionally, those with suspicious infectious or inflammatory diseases in (18)F-fluorodeoxyglucose positron-emission tomography/computed tomography were also excluded. Serum PCT concentrations were measured using a Kryptor system (BRAHMS) and a clinical cut-off at 0.5 ng/mL was used to define positive results. RESULTS: Serum PCT concentrations did not change at different cancer stages (Kruskal-Wallis, p>0.05). No patient had a PCT concentration >0.5 ng/mL. CONCLUSIONS: Our data show that solid carcinomas "per se" did not increase circulating PCT concentrations, regardless of the histotype and stage of the disease.

(99m)Tc-sestamibi scanning in thyroid nodules with nondiagnostic cytology.

BACKGROUND: Our aim in this study was to assess the relevance of (99m)Tc-sestaMIBI (MIBI) scan in the diagnostic evaluation of thyroid nodules with nondiagnostic cytology. METHODS: In all, 74 patients with a single nodule and repeatedly nondiagnostic ultrasound-guided fine-needle aspiration cytology (US-FNAC) were enrolled. In all cases thyroid nodules were cold in (99m)Tc-pertechnetate (Tc) scans. Thyroid scans were also acquired 30 and 120 minutes after intravenous administration of MIBI. Nodules that concentrate MIBI were considered as positive (ie, suspicious for malignancy). Histologic findings were obtained after surgery in all patients. RESULTS: No differences occurred in early and late MIBI images. None of 63 patients with a negative MIBI scan had a final histologic diagnosis of malignancy (ie, no false-negative results). Two patients with a final histologic diagnosis of papillary thyroid carcinoma (PTC) and 1 with follicular thyroid carcinoma (FTC) had a positive MIBI scan. Eight patients with a final histologic diagnosis of benign lesions (3 with follicular adenomas) also had MIBI-positive scans. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were, respectively, 100%, 88%, 89%, 27%, and 100%. CONCLUSIONS: A negative MIBI scan in a cold nodule accurately excludes malignancy when US-FNAC is reported as nondiagnostic. This avoids the need for more invasive diagnostic procedures (ie, surgery) and positively influences the cost-effectiveness profile. A MIBI scan may be performed by acquiring images 30 minutes after tracer administration alone. Histology is still necessary to distinguish benign from malignant disease in a MIBI-positive nodule but unnecessary surgery could have been reduced from 71 to 8 cases in our series.