Long-term Follow-up of a Toddler with Papillary Thyroid Carcinoma: A Case Report with a Literature Review of Patients Under 5 Years of Age

Papillary thyroid cancer (PTC) is extremely rare in children. Herein, we present a case diagnosed with PTC at 15 months of age. We conducted a literature review of the published cases with PTC under five years of age. A 1.25-year-old male patient had initially presented with a complaint of progressively enlarging cervical mass that appeared four months earlier. On physical examination, a mass located in the anterior cervical region with the largest measurements of around 3x3 cm was detected. Cervical and thyroid ultrasonography showed a 50x27 mm solid mass in the right lateral neck. Excisional biopsy revealed a follicular variant of PTC with capsular invasion. Subsequently, he underwent a complementary total thyroidectomy. He was diagnosed with intermediate-risk (T3N0M0) PTC. He developed permanent hypoparathyroidism. In the first year of the operation, he was treated with radioiodine ablation (RAI) since basal and stimulated thyroglobulin (Tg) levels tended to increase. Whole-body scintigraphy was normal in the first year of RAI ablation. On levothyroxine sodium (LT4) treatment, levels of thyroid stimulating hormone (TSH) and Tg were adequately suppressed. He is now 8.5-years-old and disease-free on LT4 replacement therapy for seven years and three months. Pediatric PTC has different biological behavior and an excellent prognosis compared to adults. The optimal treatment strategy for pediatric TC is total thyroidectomy, followed by RAI ablation. Post-operative management should include regular follow-up, TSH suppression by adequate LT4 therapy, serial Tg evaluation, and radioiodine scanning when indicated.

Squamous Cell Carcinoma Mimicking Neck Paraganglioma on 68Ga-DOTATATE PET/CT.

ABSTRACT: Somatostatin receptor (SSTR) imaging with 68Ga-labeled somatostatin analogs has been used for many tumors with high SSTR expression. Increased uptake mostly depends on the SSTR status of tumors; however, false-positive uptake can be demonstrated in benign diseases or other malignancies because of the increased SSTR expression. We present a case of a 50-year-old man with increased SSTR activity on cervical lesion located in internal jugular chain in 68Ga-DOTATATE PET/CT, which was performed for suspicion of paraganglioma. Biopsy revealed lymph node metastasis of squamous cell carcinoma other than paraganglioma. 18F-FDG PET/CT showed primary malignancy on larynx and lymph node metastasis, which were correlated surgically.

Prognostic significance of 68Ga-Pentixafor PET/CT in multiple myeloma recurrence: a comparison to 18F-FDG PET/CT and laboratory results.

PURPOSE: This study investigates the prognostic value of 68Ga-Pentixafor PET/CT using PET-derived quantitative in multiple myeloma (MM) patients with suspected recurrence in comparison to 18F-FDG PET/CT and clinical data. METHODS: Twenty-four MM patients with suspicion for relapse who underwent 68Ga-Pentixafor and 18F-FDG PET/CT were retrospectively evaluated. Total bone marrow glycolysis for 18F-FDG (TBMFDG) and total bone marrow uptake for 68Ga-Pentixafor PET/CT (TBMCXCR4) were calculated using whole-body metabolic tumor burden obtained by dedicated software (MIM 7.0.6). The patients were followed for 19-24 months, and the association of PET-derived quantitative data with overall survival (OS) was analyzed. RESULTS: 68Ga-Pentixafor PET/CT was positive in 17 patients, of which 13 were also positive on 18F-FDG PET/CT, whereas 7 patients were negative on both scans. The positive rate of 68Ga-Pentixafor and 18F-FDG PET/CT on a patient-based approach was 70.8% and 54.1%, respectively. 68Ga-Pentixafor positivity was significantly associated with OS (p = 0.009), and 18F-FDG positivity was at the margin of statistical significance (p = 0.056). TBMCXCR4 and TBMFDG were negatively correlated with OS (r = -0.457, p = 0.025 and r = -0.617, p = 0.001, respectively). The OS was negatively correlated with beta-2-microglobulin levels (r = -0.511, p = 0.01) and CRAB score (r = -0.592, p = 0.002) as an indicator of the end-organ disease, which confirmed these results. Serum beta-2-microglobulin levels and CRAB score were also correlated with TBMCXCR4 (r = 0.442, p = 0.039 and r = 0.573, p = 0.003, respectively) and TBMFDG (r = 0.543, p = 0.009 and r = -0.424, p = 0.003, respectively). CONCLUSION: 68Ga-Pentixafor PET/CT positivity is a negative prognostic factor in the survival outcome of MM patients. Complementary 68Ga-Pentixafor PET/CT has the potential to overcome 18F-FDG PET/CT limitations and helps a more precise risk stratification.

Radionuclide Therapy With 177Lu-PSMA in a Case of Metastatic Adenoid Cystic Carcinoma of the Parotid.

In vivo prostate-specific membrane antigen (PSMA) overexpression creates an opportunity for PSMA-directed theranostic approach in adenoid cystic carcinoma of the parotid. Herein, we illustrate a patient with metastatic PSMA-directed theranostic approach in adenoid cystic carcinoma of the parotid who had intense PSMA uptake on metastatic lesions, followed by radionuclide therapy with Lu-PSMA.

Pathogens isolated from deep soft tissue and bone in patients with diabetic foot infections.

BACKGROUND: We sought to determine the similarity of pathogens isolated from soft tissue and bone in patients with diabetic foot infections. It is widely believed that soft-tissue cultures are adequate in the determination of causative bacteria in patients with diabetic foot osteomyelitis. The culture results of specimens taken concurrently from soft-tissue and bone infections show that the former does not predict the latter with sufficient reliability. We sought to determine the similarity of pathogens isolated from soft tissue and bone in patients with diabetic foot infections. METHODS: Forty-five patients with diabetic foot infections were enrolled in the study. Patients had to have clinically suspected foot lesions of grade 3 or higher on the Wagner classification system. In patients with clinically suspected osteomyelitis, magnetic resonance imaging, scintigraphy, or histopathologic examination were performed. Bone and deep soft tissue specimens were obtained from all patients by open surgical procedures under aseptic conditions during debridement or amputation. The specimens were compared only with the other specimens taken from the same patients. RESULTS: The results of bone and soft-tissue cultures were identical in 49% (n = 22) of cases. In 11% (n = 5) of cases there were no common pathogens. In 29% (n = 13) of cases there were more pathogens in the soft-tissue specimens; these microorganisms included microbes isolated from bone cultures. In four patients (9%) with culture-positive soft-tissue specimens, bone culture specimens remained sterile. In one patient (2%) with culture-positive bone specimen, soft-tissue specimen remained sterile. CONCLUSION: Culture specimens should be obtained from both the bone and the overlying deep soft tissue in patients with suspected osteomyelitis whose clinical conditions are suitable. The decision to administer antibiotic therapy should depend on these results.

Imaging of Chemokine Receptor CXCR4 in Mycosis Fungoides Using 68Ga-Pentixafor PET/CT.

A 52-year-old woman diagnosed with mycosis fungoides was referred for F-FDG PET/CT before treatment for the evaluation of disease severity. The patient also underwent Ga-pentixafor PET/CT for further evaluation. FDG uptake was observed in cervical, axillary, and pelvic lymph nodes and multiple widespread skin lesions throughout the body, suggestive of extensive involvement of mycosis fungoides. All lesions were visually identifiable with high target-to-background ratio on Ga-pentixafor PET/CT which demonstrated marked CXCR4 expression in all lesions that were detected using F-FDG PET/CT.

Detection of bone marrow involvement with FDG PET/CT in patients with newly diagnosed lymphoma.

BACKGROUND: Bone marrow involvement (BMI) affects the lymphoma stage, survival, and treatment. Bone marrow biopsy (BMB) and fluorodeoxyglucose (FDG) positron emission tomography- computed tomography (PET/CT) are useful techniques to detect BMI. Both have advantages and disadvantages. We aimed to identify factors that could be used to predict BMI with positive and negative results on PET/CT compare them with BMB in newly diagnosed patients with lymphoma. METHODS: We included 22 non-Hodgkin and 16 Hodgkin lymphoma patients in this single center study. All patients had PET/CT examination and BMB before treatment. BMI in BMB was reported as negative or positive. Bone marrow was classified into 3 types by FDG uptake on PT/CT; diffuse involvement, focal involvement, and normal bone marrow. RESULTS: PET/CT and BMB results were concordant (7 positive, 15 negative) in 22 patients (57%). We evaluated concordant and discordant patient characteristics and risk-stratified patients for BMI. Our findings suggest that patients with diffuse FDG uptake on PET/CT, especially patients with advanced age and low platelet and white blood cell counts, are likely to have BMI and could potentially forego BMB. Patients with negative PET/CT findings and no significant laboratory abnormalities are very unlikely to have BMI. CONCLUSION: Our results suggest that BMI should not be decided solely based PET/CT or BMB findings. It is reasonable to use both diagnostic assays along with clinical and laboratory findings. PET/CT result, clinical and laboratory findings could be useful for predicting BMI in patient for whom BMB is contraindicated.

Frontal and occipital perfusion changes in dissociative identity disorder.

The aim of the study was to investigate if there were any characteristics of regional cerebral blood flow (rCBF) in dissociative identity disorder. Twenty-one drug-free patients with dissociative identity disorder and nine healthy volunteers participated in the study. In addition to a clinical evaluation, dissociative psychopathology was assessed using the Structured Clinical Interview for DSM-IV Dissociative Disorders, the Dissociative Experiences Scale and the Clinician-Administered Dissociative States Scale. A semi-structured interview for borderline personality disorder, the Hamilton Depression Rating Scale, and the Childhood Trauma Questionnaire were also administered to all patients. Normal controls had to be without a history of childhood trauma and without any depressive or dissociative disorder. Regional cerebral blood flow (rCBF) was studied with single photon emission computed tomography (SPECT) with Tc99m-hexamethylpropylenamine (HMPAO) as a tracer. Compared with findings in the control group, the rCBF ratio was decreased among patients with dissociative identity disorder in the orbitofrontal region bilaterally. It was increased in median and superior frontal regions and occipital regions bilaterally. There was no significant correlation between rCBF ratios of the regions of interest and any of the psychopathology scale scores. An explanation for the neurophysiology of dissociative psychopathology has to invoke a comprehensive model of interaction between anterior and posterior brain regions.

The genotoxic effects in lymphocyte cultures of children treated with radiosynovectomy by using yttrium-90 citrate colloid.

UNLABELLED: The aim of this study was to investigate the genotoxic effect on the peripheral blood lymphocytes potentially induced by yttrium-90 citrate colloid (Y-90) in children who were undergoing radiosynovectomy for hemophilic synovitis, using chromosomal aberration analysis (CA) and the micronuclei (MN) assay for detecting chromosomal aberrations, as well as the sister chromatid exchanges (SCE) technique for assessed DNA damage. MATERIALS AND METHODS: Cytogenetic analyses were undertaken in 18 boys (mean age, 14.5 +/- 2.1 years) with hemophilic synovitis who underwent radiosynovectomy with Y-90. CA, MN, and SCE were evaluated just prior to, then at 2 and 90 days following radiosynovectomy from the peripheral lymphocytes of the children. An activity of 185 MBq of Y-90 was injected into the 18 knee joints under aseptic conditions. To check the possibility of leakage from the joint and its migration within the body, the patients underwent scanning under a dual-headed gamma camera at the hours 2 and 48 following the procedure. RESULTS: The procedure was well tolerated in all the children, and there was no extra-articular activity owing to extra-articular leakage of radioactive material in whole-body imaging. The mean frequency of CA in lymphocytes determined prior to the onset of therapy (0.31 +/- 0.48/900 cells) was not significantly increased, in comparison to the control values obtained 2 (0.30 +/- 0.48/900 cells) and 90 days (0.15 +/- 0.37/900 cells) after radiosynovectomy (p = 1.0 and 0.625, respectively). We observed that MN frequency was mildly increased in lymphocytes 2 days after therapy (8.30 +/- 1.89 MN/1000 binucleated cells vs. 9.23 +/- 1.79 MN/1000 binucleated cells; p = 0.013). But there was no significant difference between the baseline and the day 90 control levels of MN (p = 0.196). In the analysis of SCE frequency, there were no significant differences between the baseline (8.11 +/- 0.77) and the control analysis performed 2 and 90 days following radiosynovectomy (8.18 +/- 0.77 and 8.07 +/- 0.74; p = 0.710 and 0.662, respectively). CONCLUSIONS: The results of this study indicated that high radiation doses are not obtained by peripheral lymphocytes of children who undergo Y-90 radiosynovectomy and, therefore, they contradict a high cancer risk.

Prediction of outcome in pediatric Hodgkin lymphoma based on interpretation of 18FDG-PET/CT according to ΔSUVmax, Deauville 5-point scale and IHP criteria.

OBJECTIVE: Minimizing side effects by using response-adopted therapy strategies plays an important role in the management of pediatric Hodgkin lymphoma (HL); however, the criteria for the definition of adequate or inadequate response are controversial. The aim of this study is to compare different methods of interpretation of 18F-FDG-PET/CT (PET) in the prediction of disease outcome in order to determine the optimum method in this regard. METHODS: Baseline, interim and post-treatment PET scans of 72 children were interpreted according to revised International Harmonization Project criteria (IHP) and Deauville criteria. Cut-off values for changes in interim and post-treatment FDG uptake (ΔSUVmax) in the prediction of progression-free survival (PFS) were measured using ROC analysis. Quantitative and visual data were compared with each other in the prediction of PFS. RESULTS: Mean interim and post-treatment ΔSUVmax of the primary lesions were 77.4 ± 19.5 and 68.8 ± 30.4% and respective cut-off values were 82 and 73%. However, only post-treatment ΔSUVmax yielded statistically significant results in the prediction of 3-year PFS (p = 0.043). Interim ΔSUVmax was further analyzed according to the values reported in the literature (66 and 77%) yet statistically significant results were not reached (p = 0.604 and 0.431). For interim evaluation, IHP criteria was correlated to Deauville criteria (p = 0.002 and p = 0.001) and ΔSUVmax (p = 0.03), whereas for post-treatment evaluation, significant correlation with ΔSUVmax (p = 0.04) but marginally significant (p = 0.055 and p = 0.058) correlation with Deauville criteria were achieved. Overall, 1, 3 and 5-year PFS were 95.7 ± 0.2, 89.6 ± 0.4 and 80.8 ± 0.7%, respectively. All methods demonstrated comparable performance in the prediction of 3-year PFS; however, interim PET using Deauville criteria and post-treatment PET using IHP criteria were statistically significant. All methods demonstrated high negative-predictive value but substantially low positive-predictive value. CONCLUSIONS: Deauville criteria are superior to other methods in the prediction of pediatric HL outcome using interim PET data. On the other hand, quantitative evaluation and visual evaluation by IHP can be used reliably at the end of the treatment. In this regard, we report the optimal cut-off value of SUVmax reduction as 73%.

Clinical Utility of Tc-99m MIBI SPECT/CT for Preoperative Localization of Parathyroid Lesions.

We aimed to demonstrate the role of SPECT/CT in preoperative localization of parathyroid lesions in patients with hyperparathyroidism who had technetium-99m (Tc-99m) methoxyisobutylisonitrile (MIBI) dual-phase parathyroid scintigraphy. We evaluated retrospectively the scintigraphic data of 103 patients who had parathyroidectomy after Tc-99m MIBI dual-phase parathyroid scintigraphy with SPECT/CT. The planar and SPECT/CT images were evaluated separately to determine their efficacy in localizing parathyroid lesions. These results were then compared with surgical data. There were 84 female and 19 male patients whose mean age was 54 ± 12 years. A total of 115 parathyroid lesions in 103 patients were resected during operations. In 87 patients, with both planar and SPECT/CT images, a total of 100 lesions could be detected correctly. In 11 patients, only SPECT/CT images could show 13 subcentimetric lesions. In three patients, three lesions were evaluated as parathyroid lesions both with planar and SPECT/CT images, but according to histopathologic evaluation, they came out to be nonparathyroidal lesions. In two patients, two parathyroid lesions could not be detected preoperatively neither with planar nor with SPECT/CT images. The lesion-based sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 87 %, 99 %, 97.1 %, 95.3 %, and 95.8 % for planar images and 98.3 %, 99 %, 97.4 %, 99.4 %, and 98.8 % for SPECT/CT images, respectively. Tc-99m MIBI parathyroid scintigraphy should be a diagnostic modality of choice in preoperative evaluation of patients with hyperparathyroidism. SPECT/CT has an incremental value both in demonstrating subcentimetric lesions and in accurately localizing lesions anatomically.

Radiosynovectomy in hemophilic synovitis: correlation of therapeutic response and blood-pool changes.

AIM: The aim of this study was to evaluate the efficacy of 90Y and 186Re radiosynovectomy in patients with hemophilic synovitis. METHODS: Radiosynovectomy was performed in 32 joints of 20 patients with hemophilic synovitis by using 90Y citrate colloid in the knee and 186Re sulfide colloid in the elbow, shoulder, and ankle. The indication for radiosynovectomy was the continuous presence of intra-articular blood or effusion and three or more hemorrhages into the same joint within the last 6 months. Response to therapy was first assessed at the 4th month with blood-pool imaging. Patients were followed up by clinical evaluation based on assessments of joint-bleeding frequency, using range of motion measurements at 6-month intervals for an average of 1 year (range, 9-15 months). RESULTS: A marked decrease (an 80%-100% decrease) in bleeding episodes was seen in 24 of 32 (75%) joints, a moderate decrease (51%-79% decrease) in 1 (9%) joint, and a mild decrease (30%-50%) in 3 (13%) joints. Frequency of intra-articular bleeding after treatment was unchanged in only 13% of the joints. The number of hemarthroses significantly decreased after therapy (p < 0.05). The mean bleeding frequency of the joints were 1.7 +/- 0.9 and 0.3 +/- 0.7 per month before and after therapy, respectively. The ratios of joints which had marked improvement after therapy were 86% in the ankle, 73% in the elbow, and 58% in the knee. There was no significant difference between percent joint range of motion limitations measured before and after therapy (p > 0.05). The correlation between therapeutic outcome (in terms of joint bleeding) and the difference of pre- and posttherapeutic blood-pool indices were significant (r = 0.594; p < 0.05), while the correlation between therapeutic outcome and pretherapeutic radiologic scale and pretherapeutic blood-pool indices were not significant (r = 0.095; p > 0.05; r = -0.089; p > 0.05, respectively). CONCLUSION: Radiosynovectomy is a simple but quite effective and efficient procedure in limiting the frequency of joint hemorrhage in patients with hemophilia. Blood-pool imaging may be an objective means for monitoring therapy response in these patients.

Role of 99mTc-hexakis-2-methoxyisobutylisonitrile for detecting marrow metastases in childhood solid tumours.

AIM: To evaluate the role of 99mTc-hexakis-2-methoxyisobutylisonitrile (99mTc-MIBI) for detecting bone marrow metastases in childhood solid tumours, including lymphomas. METHODS: Twenty-six children (18 males, eight females) were studied. They all had proven malignant solid tumours [Hodgkin's lymphoma (5), non-Hodgkin's lymphoma (3), neuroblastoma (9), Ewing's sarcoma (3), Langerhans cell histiocytosis (4), rhabdomyosarcoma (1) and germ cell tumour (1)] with suspected bone marrow metastases. All patients underwent computed tomography and/or magnetic resonance imaging, 99mTc-MIBI and Tc-methylene diphosphonate bone scans and bone marrow aspiration and/or biopsy. The scintigraphic evaluation of 99mTc-MIBI scans was performed according to the visual assessment of the extent and intensity of uptake. The scintigraphic score, which is the sum of the extent and intensity of uptake, was calculated for each patient. Scores of more than 2 were considered to be positive for bone marrow involvement. RESULTS: Twenty-seven 99mTc-MIBI scans were studied for 26 patients. Twenty-two 99mTc-MIBI scans were accepted as normal bone marrow. Bone scans were also normal in these patients. Five of the 27 99mTc-MIBI scans had scores of more than 2. Bone marrow cytology revealed bone marrow metastases in these patients. CONCLUSION: Abnormal 99mTc-MIBI uptake correlated extremely well with bone marrow aspiration/biopsy cytology results. Non-invasive 99mTc-MIBI imaging in children with malignant solid tumours appears to be promising for the evaluation of bone marrow metastases.

Evaluation of regional cerebral blood flow changes in panic disorder with Tc99m-HMPAO SPECT.

The objective of this study is to investigate differences in regional cerebral blood flow (rCBF) and rCBF asymmetry index values between panic disorder patients (n=22) and normal comparison subjects (n=19) using Tc99m-hexamethylpropyleneamine oxime single photon emission tomography imaging. A decrease in perfusion in the bilateral frontal regions and a relative increase in perfusion in the right medial and superior frontal regions were found. There were significant positive correlations between scores on the Panic and Agoraphobia Scale and rCBF asymmetry index values of the parietal, superior temporal and lateral temporal regions in the panic disorder patients. These correlations point to a relationship between the severity of panic disorder and relative right brain activation. Activation of the amygdala, increased CBF in the frontal region, or hyperactivation of the locus ceruleus seen in panic disorder may explain the decrease in the rCBF in the inferior frontal region.

[Evaluation of regional cerebral blood flow changes in panic disorder with Tc99m-HMPAO SPECT]. / Panik bozuklugunda bölgesel beyin kan akimi degisikliklerinin Tc99m-HMPAO SPECT ile degerlendirilmesi.

OBJECTIVE: To evaluate the differences in regional cerebral blood flow (rCBF) and rCBF asymmetry index values of panic disorder patients and a control group, using Tc99m-HMPAO SPECT. In addition, the influence of comorbid agoraphobia on the rCBF and rCBF asymmetry index values of the panic disorder patients was also investigated. METHOD: The rCBF and rCBF asymmetry index values of 22 panic disorder patients, 9 with agoraphobia and 13 without agoraphobia, and 19 healthy controls were obtained using SPECT. Both (1) the panic disorder and control groups and (2) panic disorder groups with and without agoraphobia were compared in terms of the measured values. RESULTS: A decrease in blood perfusion in the bilateral frontal region, a relative increase in blood perfusion in the right medial frontal and right superior frontal regions and a relative blood flow increase in the right medial frontal region according to rCBF asymmetry index values were determined in panic disorder patients. In the patients with agoraphobia, the decrease in blood perfusion in the right occipital region, and the relative increase in the right superior temporal region according to rCBF asymmetry index values were significantly higher than those in subjects without agoraphobia. CONCLUSION: The decrease in the rCBF in the bilateral inferior frontal regions in panic patients may be related to the amygdala activation decreasing cerebral blood flow in the frontal region and/or the hyperactivation of the locus ceruleus. The explanations of the etiology of panic disorder are valid only if they are supported with clinical evidence from future studies.

Impact of Nonosseous Findings on (18)F-NaF PET/CT in a Patient with Ductal Breast Carcinoma.

(18)F-NaF was used as a bone-seeking PET tracer for skeletal imaging until the introduction of the widely available (99m)Tc-labeled bone agents. However, there is renewed clinical interest in (18)F-NaF since prior technical and logistic limitations to its routine use are no longer present, and, as a consequence, it is likely that uptake unrelated to bone and non-osseous findings will be encountered more frequently. As a result of tumoral necrosis, soft tissue metastases may demonstrate (18)F-NaF avidity due to dystrophic calcification. On the other hand, all non-osseous findings, whether (18)F-NaF avid or not, may provide important diagnostic information that may alter the course of the disease, including treatment options. Herein we present a patient with ductal carcinoma of the breast in whom findings unrelated to the skeletal system in (18)F-NaF PET/CT altered the treatment strategy.

Can complementary 68Ga-DOTATATE and 18F-FDG PET/CT establish the missing link between histopathology and therapeutic approach in gastroenteropancreatic neuroendocrine tumors?

UNLABELLED: Gastroenteropancreatic neuroendocrine tumors (GEPNETs) are indolent neoplasms presenting unpredictable and unusual biologic behavior that causes many clinical challenges. Tumor size, existence of metastasis, and histopathologic classification remain incapable in terms of treatment decision and prognosis estimation. This study aimed to compare (68)Ga-DOTATATE and (18)F-FDG PET/CT in GEPNETs and to investigate the relation between the complementary PET/CT results and histopathologic findings in the management of therapy, particularly in intermediate-grade patients. METHODS: The relation between complementary (68)Ga-DOTATATE and (18)F-FDG PET/CT results of 27 GEPNET patients (mean age, 56 y; age range, 33-79 y) and histopathologic findings was evaluated according to grade and localization using standardized maximum uptake values and Ki67 indices. Grade 2 (G2) patients were further evaluated in 2 groups as G2a (3%-9%) and G2b (10%-20%) according to Ki67 indices. RESULTS: The sensitivity of (68)Ga-DOTATATE and (18)F-FDG PET/CT was 95% and 37%, respectively, and the positive predictive values were 93.8% and 36.2%, respectively. The sensitivity in detecting liver metastasis, lymph nodes, bone metastasis, and primary lesion was 95%, 95%, 90%, and 93% for (68)Ga-DOTATATE and 40%, 28%, 28%, and 75% for (18)F-FDG, respectively. Statistically significant differences were found between grades 1-2, 2a-2b, and 1-2b with respect to (68)Ga-DOTATATE PET/CT as well as between 1-2a and 1-2b with respect to (18)F-FDG PET/CT. However, no statistical differences were found between 1 and 2a (P > 0.05) for (68)Ga-DOTATATE and 2a and 2b (P = 0.484) for (18)F-FDG. The impact of the combined (18)F-FDG and (68)Ga-DOTATATE PET/CT on the therapeutic decision was 59%. CONCLUSION: Combined (68)Ga-DOTATATE and (18)F-FDG PET/CT is helpful in the individual therapeutic approach of GEPNETs and can overcome the shortcomings of histopathologic grading especially in intermediate-grade GEPNETs.

Physiological and tumoral uptake of (68)Ga-DOTATATE: standardized uptake values and challenges in interpretation.

PURPOSE: The objective of this study is to determine the range of SUVmax of 68Ga-DOTATATE in normal organs and tumoral lesions and establish uptake unrelated to NET. MATERIALS AND METHODS: One hundred and twenty patients (57 men, 63 women), who underwent (68)Ga-DOTATATE PET/CT imaging in our institution were analyzed. Patients were indicated for (68)Ga-DOTATATE PET/CT imaging to detect primary tumor or metastasis of suspected or previously known NET, to determine SSTR positivity and to detect occult source of ectopic Cushing syndrome. Normal range of uptake was calculated for the organs that were proven to have no pathology by either conventional radiological imaging or clinical follow-up, using SUVmax as a semiquantitative measure. Uptake and tumor to background (T/B) ratios of tumoral lesions in liver, pancreas, bone, brain and lymph nodes were calculated. Uptakes due to lesions unrelated to NET were also documented. RESULTS: Significant uptake was found in spleen, kidneys, adrenal glands, liver and pituitary gland with mean SUVmax of 24.67, 14.30, 13.73, 9.12 and 9.74 respectively. Uptake was measured separately for the pancreatic head and body separately, however, besides a slightly heterogeneous uptake; the difference was not statistically significant. Uptake in the tumoral lesions had high (T/B) ratios with mean SUVmax of 28.72, 25.21, 18.28, 34.73 and 12.59 for liver, pancreas, bone, brain and lymph nodes, respectively. Incidental benign tumoral lesions were detected in 3 patients (2.5 %) which were meningioma and fibrous dysplasia demonstrating significant and breast fibroadenoma demonstrating mild (68)Ga-DOTATATE uptake. Non-neoplastic processes were detected in 4 patients (14.1 %), including postsurgical inflammation, reactive lymph nodes, arthritis and demonstrated faint to mild (68)Ga-DOTATATE uptake, with the exception of significant uptake in accessory spleen. CONCLUSION: (68)Ga-DOTATATE has high T/B ratio with physiological biodistribution comparable to its counterparts. However, the presence of SSTRs in benign and malignant lesions unrelated to NET may be challenging in interpretation particularly where the physiological uptake is variable.

Bone marrow necrosis secondary to imatinib usage, mimicking spinal metastasis on magnetic resonance imaging and FDG-PET/CT.

Imatinib mesylate has become the treatment of choice for gastrointestinal stromal tumors (GISTs) and has made a revolutionary impact on survival rates. Bone marrow necrosis is a very rare adverse event in malignant GIST. Bone metastases are also rarely encountered in the setting of this disease. The authors report on a patient with malignant GIST who developed a bone lesion, mimicking spinal metastasis on both MR imaging and FDG-PET/CT. Corpectomy and anterior fusion was performed, but the pathology report was consistent with bone marrow necrosis. Radiological and clinical similarities made the distinction between metastasis and bone marrow necrosis challenging for the treating physicians. Instead of radical surgical excision, more conservative methods such as percutaneous or endoscopic bone biopsies may be more useful for pathological confirmation, even though investigations such as MR imaging and FDG-PET/CT indicate metastatic disease.