Clinical factors associated with autologous stem cell transplantation outcomes in multiple myeloma: upfront transplant with MEL200 remains the standard of care.

Autologous stem cell transplantation (ASCT) remains the mainstay of the treatment in newly diagnosed transplant-eligible multiple myeloma (MM) patients. This retrospective study was performed to investigate the potential prognostic markers which may modify transplant course in a total of 256 ASCT recipients [median age: 58 (30-74) years; male/female: 138/118], including pretransplant (PET0) and day + 60 (PET2) PET/CT assessments and comparative analysis of melphalan (Mel) dose. Better responses with significantly higher complete response/very good partial response rates were achieved in patients who proceeded to transplant within 301 days from diagnosis (p < 0.001). Patients who had received < 1.5 lines of treatment prior to transplant had significantly higher probability of overall survival (OS) (p = 0.004) and progression-free survival (PFS) (p < 0.001). The probability of OS was significantly higher in patients with low Eastern Cooperative Oncology Group (ECOG) performance score (PS = 0-1) (p = 0.003) and HCT-Comorbidity Index (HCT-CI = 0) (p = 0.011). The number of involved areas (p = 0.028) and maximum standardized uptake value (SUVmax) (p = 0.021) in PET0 represented significant impact on OS. The probabilities of OS (p < 0.001) and PFS (p = 0.01) were significantly better with Mel200 mg/m2 conditioning compared to Mel140 mg/m2. Conditioning with Mel200 mg/m2, early and upfront ASCT and low pretransplant treatment burden were found to be significantly associated with ASCT outcome in MM patients. Despite its predictor impact on survival and prognosis, further studies are warranted to standardize PET/CT-based response assessments before being used as a guide for treatment decisions in clinical practice.

Quantitative and visual analyses of the effect of activity reduction on image metrics and quality in 18F-FDG PET/MRI in pediatric oncology.

BACKGROUND: : The aim of our study was to evaluate the effect of reduced injected tracer activities on the quantitative image metrics and the visual image quality in whole-body 18F-FDG PET/MRI with TOF capability in pediatric oncology. METHODS: Seventy-seven PET/MRI examinations of 54 patients were analyzed (standard injected activity: 1.9 MBq/kg, standard PET scan duration: 5 min per bed position). Lower activity PET images (1.2 MBq/kg and 0.9 MBq/kg) were retrospectively simulated from the originally acquired list-mode data sets. Quantitative parameters were assessed by measuring the SUV metrics, signal-to-noise ratio (SNR), contrast-to-noise ratios (CNR), and textural features in each PET data set. PET images were also evaluated visually for image quality by using a scoring system. RESULTS: SNRs were found as significantly different among PET data sets (p < 0.001) and showed increasing image noise with decreasing activities. CNR values did not show significant differences among PET data sets. The mean relative percentage changes in SUV metrics were found to be lower in 1.2 MBq/kg data set compared to 0.9 MBq/kg data set. Lesion SUVmax, SUVmean, SULpeak, and textural features were significantly different in 0.9 MBq/kg data set compared to the original data set (p < 0.05 for all). However, SUV metrics and textural features did not show a significant difference between the original and 1.2 MBq/kg data sets. While, the mean visual scores in 0.9 MBq/kg data set were significantly different compared to the original data set (p < 0.001), there was no significant difference between the original and 1.2 MBq/kg data sets in terms of general image quality and image sharpness. DISCUSSION: Our analyses showed that the reduction of injected activity to 1.2 MBq/kg may be feasible in pediatric oncological PET/ MRI, with a smaller relative percentage change in quantitative parameters and with similar image quality to the original data set.

Diagnostic utility of serum biomarkers in large vessel vasculitis and their correlation with positron emission tomography.

OBJECTIVES: To investigate the association between vascular inflammation, as detected by positron emission tomography (PET) imaging and interleukin-6 (IL-6), pentraxin3, and B-cell-activating factor (BAFF) in subjects with LVV. METHODS: The study included newly diagnosed giant cell arteritis (GCA, n = 27) or Takayasu arteritis (n = 9) patients and healthy control (HC, n = 31) subjects. PET scan and blood samples were obtained before the introduction of treatments. IL-6, PTX3, and BAFF levels were determined quantitatively by enzyme-linked immunosorbent assay kits. RESULTS: Thirty-six patients with LVV (20 females, 16 males; age 64.5 ± 16.6 years) and 31 HC (14 females, 17 males; age 37.1 ± 9.6 years) were included. Serum levels of IL-6, PTX3, and BAFF were increased in patients with newly diagnosed LVV compared with healthy control subjects. In receiver operating characteristics (ROC) analysis, serum IL-6 and BAFF provided excellent discrimination of newly diagnosed LVV patients from HC (area under the ROC curve of >0.90 and >0.80, respectively). None of the inflammatory markers correlated with vascular inflammatory activity determined by PET scanning. CONCLUSIONS: Our results suggest that IL-6 and BAFF may serve as markers of large vessel vasculitis, while PTX3 is not useful. None of the inflammatory markers correlated with PET assessed vasculitis activity.

The role of histopathological and biochemical parameters for predicting metastatic disease on 68 Ga-PSMA-11 PET in prostate cancer.

BACKGROUND: The aim of this study was to evaluate the role of histopathological and biochemical parameters in the prediction of the presence and number of PSMA positive lesions consistent with the metastatic spread of prostate cancer on 68 Ga-PSMA PET images. METHODS: Biochemical, histopathological and imaging data of 302 prostate cancer patients who underwent 68 Ga-PSMA-11 PET/CT or PET/MR imaging for primary staging were retrospectively analyzed. Patients were divided into two groups as "PET positive" and "PET negative" according to the presence of pathologic extraprostatic PSMA involvement. "PET positive" patients were additionally divided into two groups: oligometastatic (1-3 metastatic lesion) and multimetastatic (>3 metastatic lesions). RESULTS: The mean age of patients was 66.8 ± 7.6 years. Imaging modality was PET/MR in 223 (73.8%) and PET/CT in 79 (26.2%) of patients. Total PSA, PSA density (PSAD), ALP, and tumor ratio in biopsy specimens were found to be significantly higher in "PET positive" group compared to "PET negative" group and in multimetastatic group compared to oligometastatic group. PET positivity was observed in 3.8% of the low-intermediate risk groups (ISUP 1-3 and total PSA ≤ 20 ng/ml and PSAD < 0.15 ng/ml/cc). This ratio was 46% in the high-risk group (ISUP 4-5 or total PSA > 20 ng/ml or PSAD ≥ 0.15 ng/ml/cc) with a relative risk of 12 (p < .001). The prediction models to predict the PET positivity and the presence of distant metastasis had AUCs of 0.901 and 0.925, respectively; with ALP, total PSA, and tumor ratio in needle biopsy specimen as significant independent predictors (p < .05). CONCLUSIONS: In this study, 68 Ga-PSMA-11 PET positivity was significantly higher in the high-risk patient group than in the low-intermediate risk groups. The prediction models used for predicting the PET positivity and the presence of distant metastasis on PET imaging were successful with high discriminatory powers. In addition to total PSA and ISUP GG, ALP and tumor ratio in biopsy specimens can be used to identify high-risk patients.

Diagnostic accuracy of 68 Ga-PSMA PET/MRI and multiparametric MRI in detecting index tumours in radical prostatectomy specimen.

OBJECTIVE: To evaluate the diagnostic accuracy of the 68 gallium (68 Ga) prostate-specific membrane antigen (PSMA) positron emission tomography/magnetic resonance imaging (PET/MRI) and multiparametric MRI (mpMRI) by region-based comparison of index tumour localisations using histopathological tumour maps of patients who underwent radical prostatectomy because of clinically significant prostate cancer. PATIENTS AND METHODS: The study included 64 patients who underwent radical prostatectomy after primary staging with mpMRI and 68 Ga-PSMA PET/MRI. Diagnostic analysis was performed by dividing the prostate into four anatomic regions as left/right anterior and left/right posterior. The extension of the lesions in mpMRI and the pathological uptake in 68 Ga-PSMA PET/MRI were matched separately for each region with the extension of the index tumour into each region. RESULTS: The sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, and the accuracy of mpMRI and 68 Ga-PSMA PET/MRI are shown as 55.7%, 91.8%, 80.6%, 77.2%, 78.1%, and 60.8%, 94.3%, 86.8% 79.8%, 83.5%, respectively. 68 Ga-PSMA PET/MRI has higher sensitivity and specificity compared with mpMRI. However, no statistically significant difference was found (P = .464). Combined imaging had significantly higher diagnostic accuracy compared with mpMRI and 68 Ga-PSMA PET/MRI (change in AUC: 0.084 and 0.046, P < .001 and P = .028, respectively), while no statistically significant difference was found between mpMRI and 68 Ga-PSMA PET/MRI (change in AUC: 0.038, P = .246). CONCLUSION: 68 Ga-PSMA PET/MRI had higher clinical diagnostic accuracy in prostate cancer compared with mpMRI. Diagnostic accuracy was significantly increased in the combined use of both imaging modalities.

Diagnostic Role of 18F-Fluorodeoxyglucose Positron Emission Tomography for the Evaluation of Patients With Inflammation of Unknown Origin.

BACKGROUND: Sometimes, the underlying causes of inflammation cannot be established despite meticulous investigation, including medical history, physical examination, laboratory tests, and radiologic procedures. Rheumatologists are often faced with patients whose condition is known as inflammation of unknown origin (IUO). Differential diagnosis of IUO is diverse, and investigation of these cases is challenging and time-consuming. OBJECTIVE: The study aimed to assess the diagnostic role of positron emission tomography/computed tomography (PET/CT) in the evaluation of patients with IUO. METHODS: The study sample consisted of 97 adult patients with IUO who have not been previously diagnosed with an infectious, inflammatory, or malignant disease. The necessary data were collected from January 2015 to June 2018 with a 6-month follow-up period. The patients were screened using PET/CT after a specific diagnosis could not be established with detailed laboratory and radiologic evaluations. RESULTS: A final diagnosis was established at follow-up, and 47 (54%) of the 97 patients had inflammatory diseases, 30 (34.4%) had malignancies, and 10 (11.4%) had infections. Despite meticulous investigation, 10 patients were left undiagnosed in the follow-up. PET/CT aided diagnosis in 59 patients (60.8%), but it was not helpful in 38 patients (39.2%). PET/CT was positive in 30 (63%) of the 47 patients with inflammatory diseases, whose final diagnosis was inflammatory rheumatic disease, as follows: large-vessel vasculitis in 19 patients, polymyalgia rheumatica in 7 patients, and seronegative arthritis or other rare miscellaneous diseases in 4 patients. The sensitivity of PET/CT was 67% with a specificity and diagnostic accuracy of 100% and 71%, respectively. CONCLUSIONS: Investigation of the underlying etiology of IUO is time-consuming and challenging. PET/CT may help identify the final diagnosis more quickly by locating an obscure inflammatory site; thus, it may reduce the number of unnecessary biopsies, diagnostic time, anxiety, work loss, morbidity, and mortality.

Dopamine transporter SPECT imaging in Parkinson's disease and parkinsonian disorders

The dopamine transporter (DAT) imaging provides an objective tool for the assessment of dopaminergic function of presynaptic terminals which is valuable for the differential diagnosis of parkinsonian disorders related to a striatal dopaminergic deficiency from movement disorders not related a striatal dopaminergic deficiency. DAT imaging with single-photon emission computed tomography (SPECT) can be used to confirm or exclude a diagnosis of dopamine deficient parkinsonism in cases where the diagnosis is unclear. It can also detect the dopaminergic dysfunction in presymptomatic subjects at risk for Parkinson's disease (PD) since the reduced radiotracer binding to DATs in striatum is already present in the prodromal stage of PD. This review covers the rationale of using DAT SPECT imaging in the diagnosis of PD and other parkinsonian disorders, specifically focusing on the practical aspects of imaging and routine clinical indications.

Evaluation of brain FDG PET images in temporal lobe epilepsy for lateralization of epileptogenic focus using data mining methods

Background/aim: In temporal lobe epilepsy (TLE), brain positron emission tomography (PET) performed with F-18 fluorodeoxyglucose (FDG) is commonly used for lateralization of the epileptogenic temporal lobe. In this study, we aimed to evaluate the success of quantitative analysis of brain FDG PET images using data mining methods in the lateralization of the epileptogenic temporal lobe. Materials and methods: Presurgical interictal brain FDG PET images of 49 adult mesial TLE patients with a minimum of 2 years of postsurgical follow-up and Engel I outcomes were retrospectively analyzed. Asymmetry indices were calculated from PET images from the mesial temporal lobe and its contiguous structures. The J48 and the logistic model tree (LMT) data mining algorithms were used to find classification rules for the lateralization of the epileptogenic temporal lobe. The classification results obtained by these rules were compared with the physicians' visual readings and the findings of single-patient statistical parametric mapping (SPM) analyses in a test set of 18 patients. An additional 5-fold cross-validation was applied to the data to overcome the limitation of a relatively small sample size. Results: In the lateralization of 18 patients in the test set, J48 and LMT methods were successful in 16 (89%) and 17 (94%) patients, respectively. The visual consensus readings were correct in all patients and SPM results were correct in 16 patients. The 5-fold cross- validation method resulted in a mean correct lateralization ratio of 96% (47/49) for the LMT algorithm. This ratio was 88% (43 / 49) for the J48 algorithm. Conclusion: Lateralization of the epileptogenic temporal lobe with data mining methods using regional metabolic asymmetry values obtained from interictal brain FDG PET images in mesial TLE patients is highly accurate. The application of data mining can contribute to the reader in the process of visual evaluation of FDG PET images of the brain.

Comparison of FDG PET/MRI and FDG PET/CT in Pediatric Oncology in Terms of Anatomic Correlation of FDG-positive Lesions.

The aims of our study were to compare F-18 fluorodeoxyglucose (FDG) positron-emission tomography/magnetic resonance imaging (PET/MRI) and PET/computed tomography (CT) in pediatric oncology patients in terms of anatomic correlation of FDG-positive lesions, and also to compare diffusion-weighted imaging (DWI) with PET to assess the correlation between apparent diffusion coefficient (ADC) values and standardized uptake value (SUV). Sequential PET/CT and PET/MRI images and/or whole-body DWI and ADC mapping in 34 pediatric patients were retrospectively analyzed. FDG-positive lesions were visually scored for CT, T1-weighted, T2-weighted, and DWI images separately in terms of anatomic correlation of FDG-avid lesions. Correlation analysis was performed for SUV parameters and ADC values. Among 47 FDG-positive lesions identified concurrently on PET/CT and PET/MRI, 37 were positive on CT and 46 were positive on at least one MRI sequence (P=0.012). Among 32 FDG-positive lesions for which DWI were available, 31 could be clearly depicted on DWI, resulting in significant difference compared with CT alone in the detection of FDG-positive lesions. No correlation was found between ADC and SUV. FDG PET/MRI exhibits better performance than PET/CT in terms of anatomic correlation of FDG-avid lesions. Therefore, PET/MRI may be more advantageous than PET/CT, not only due to reduced ionizing radiation dose but also for a better depiction of FDG-avid lesions in pediatric PET imaging.

Successful multimodal treatment for aggressive metastatic and recurrent fibrolamellar hepatocellular carcinoma in a child.

Fibrolamellar variant of hepatocellular carcinoma (FLHCC) does not have a favorable prognosis than conventional HCC, and there is no difference regarding the response to chemotherapy and the degree of surgical resectability. FLHCC commonly recurs after complete surgical resection, and there is a high rate of lymph node metastases. Herein, we report a 12-year-old girl with metastatic FLHCC with multiple recurrences aggressively treated with surgery, chemotherapy, and antiangiogenic agents. She is in complete remission after 4 years and 2 months after the diagnosis of metastatic FLHCC. The standard treatment of FLHCC is excision of the primary tumor and its metastases. Chemotherapy for FLHCC is controversial, and it has been suggested that cytoreductive chemotherapy was ineffective and adjuvant chemotherapy did not improve survival. Our patient with multiple recurrences was successfully treated with surgery, first-line chemotherapy with cisplatin and doxorubicin, second-line chemotherapy with 5-fluorouracil/interferon-α combination, and adjuvant antiangiogenic agents like cyclophosphamide and thalidomide. As FLHCC patients have no underlying liver disease, they can tolerate higher doses of chemotherapy compared with conventional HCC patients. We support the use of repeated aggressive surgery with adjuvant chemotherapy and antiangiogenic therapy, which provided complete remission in our patient with metastatic and recurrent FLHCC.

PSMA-Avid Liver Metastasis in a Case of Prostate Carcinoma and Poorly Differentiated Thyroid Carcinoma.

ABSTRACT: Although PSMA-targeted PET imaging is predominantly used for prostate carcinoma (PC), it has also been reported for thyroid carcinoma (TC). A 77-year-old man had a liver metastasectomy for poorly differentiated TC, which had elevated 18 F-FDG uptake. Two years later, he was diagnosed with acinar-type modified Gleason score of 7 (3 + 4) PC. Four years later, he had metastatic liver lesions that had no radioactive iodine and 18 F-FDG avidity. These lesions were 68 Ga-PSMA avid, and the biopsy confirmed TC metastasis. This case emphasizes the importance of 68 Ga-PSMA-based imaging in poorly differentiated TC and pathological confirmation for lesions that were 68 Ga-PSMA-positive.

The role of positron emission tomography with 18F-fluorodeoxyglucose in nodal staging of clinical and radiological N0 head and neck cancers.

The objective of the study was to evaluate the impact of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) imaging on nodal staging for head and neck cancers. This was a retrospectively analyzed single institution study. The study population consisted of 36 patients with head and neck cancers who were evaluated with PET/CT and went on to neck dissection. All of them had clinically and radiographically negative neck (N0) and each patient underwent PET/CT imaging before undergoing selective neck dissection for N0 disease. Tissues were submitted for histopathologic examination and were oriented for the pathologist to permit correlation between the histopathologic findings and the imaging results. The sizes of the lymph nodes and the maximum standardized uptake values (SUVmax) measured from PET/CT images were compared with the histopathologic findings. All primary tumors were visualized with PET/CT. On histopathological examination, 19 patients had positive and 17 patients had negative lymph nodes. Receiver operating characteristic analyses were used to predict the optimal corrected SUVmax cutoffs; the optimal value was 2.95 for respective outcomes of lymph node involvement. This cutoff value yielded 84.2% sensitivity and 76.5% specificity for nodal-level staging. PET/CT proved to be accurate in 27 (75%) patients and inaccurate in 9 (25%) patients. PET/CT was a valuable tool to assess nodal stage of head and neck cancers, and should be considered before surgical treatment.

Relationship Between Metabolic Activity, Cellularity, Histopathological Features of Primary Tumors and Distant Metastatic Potential in Breast Cancer.

Objectives: The aim of this study was to evaluate the relationship between the types of distant metastatic spread, histopathological features, and imaging features of primary tumor on positron emission tomography/magnetic resonance imaging (PET/MRI) for primary staging in newly diagnosed breast invasive ductal carcinoma (IDC) patients. Methods: Data from 289 female patients were retrospectively evaluated. Maximum standardized uptake value, metabolic tumor volume (MTV), total lesion glycolysis (TLG), and minimum apparent diffusion coefficient (ADCmin) values of primary tumors were obtained from PET/MRI. The patients were grouped as non-metastatic, oligometastatic (1-5 metastatic lesions) and multimetastatic (>5 metastatic lesions) disease according to the number of distant metastases, and divided into two groups as isolated bone metastasis (IBM) and mixed/soft tissue metastasis (M-SM) groups according to the sites of metastatic spread. Results: Metabolic parameters had higher values and ADCmin had lower values in the multimetastatic and oligometastatic groups than in the non-metastatic group. MTV was the only parameter that showed significant difference between the multimetastatic and oligometastatic groups. MTV and TLG were significantly higher in the M-SM group than in the IBM group. 18F-fluorodeoxyglucose PET parameters had significantly higher values in grade 3, hormone receptor negative, human epidermal growth factor receptor 2 positive, triple negative, and highly proliferative (Ki-67 ≥14%) tumors. The prediction models that included imaging parameters to predict the presence of distant metastasis had higher discriminatory powers than the prediction models that included only histopathological parameters. Conclusion: Primary tumors with higher metabolic-glycolytic activity and higher cellularity were more aggressive and had higher metastatic potential in breast IDC. Compared with histopathological parameters alone, the combination of imaging parameters and histopathological features of primary tumors may help to better understand tumor biology and behavior.

Hybrid PET/MRI with Flutemetamol and FDG in Alzheimer's Disease Clinical Continuum.

AIMS: We aimed to investigate the interaction between ß -amyloid (Aß) accumulation and cerebral glucose metabolism, cerebral perfusion, and cerebral structural changes in the Alzheimer's disease (AD) clinical continuum. BACKGROUND: Utility of positron emission tomography (PET) / magnetic resonance imaging (MRI) hybrid imaging for diagnostic categorization of the AD clinical continuum including subjective cognitive decline (SCD), amnestic mild cognitive impairment (aMCI) and Alzheimer's disease dementia (ADD) has not been fully crystallized. OBJECTIVE: To evaluate the interaction between Aß accumulation and cerebral glucose metabolism, cerebral perfusion, and cerebral structural changes such as cortex thickness or cerebral white matter disease burden and to detect the discriminative yields of these imaging modalities in the AD clinical continuum. METHODS: Fifty patients (20 women and 30 men; median age: 64 years) with clinical SCD (n=11), aMCI (n=17) and ADD (n=22) underwent PET/MRI with [18F]-fluoro-D-glucose (FDG) and [18F]- Flutemetamol in addition to cerebral blood flow (CBF) and quantitative structural imaging along with detailed cognitive assessment. RESULTS: High Aß deposition (increased temporal [18F]-Flutemetamol standardized uptake value ratio (SUVr) and centiloid score), low glucose metabolism (decreased temporal lobe and posterior cingulate [18F]-FDG SUVr), low parietal CBF and right hemispheric cortical thickness were independent predictors of low cognitive test performance. CONCLUSION: Integrated use of structural, metabolic, molecular (Aß) and perfusion (CBF) parameters contribute to the discrimination of SCD, aMCI, and ADD.

Cerebral vasomotor reactivity across the continuum of subjective cognitive impairment, amnestic mild cognitive impairment and probable Alzheimer's dementia: A transcranial Doppler and PET/MRI study.

Cerebrovascular dysfunction has been suggested as a physiomarker of Alzheimer's disease (AD)-associated neuronal degeneration, but the underlying mechanisms are still debated. Herein cerebral vasomotor reactivity (VMR, breath-hold index: BHI), metabolic activity (lobar SUVs, FDG PET MRI), amyloid load (Centiloid score, Flutemetamol PET MRI), hemispheric cortical thickness, white matter lesion load and cerebral blood flow (ASL) were studied in 43 consecutive subjects (mean age: 64 years, female 13), diagnosed with subjective cognitive impairment (SCI, n = 10), amnestic mild cognitive impairment (aMCI, n = 15), and probable Alzheimer's dementia (AD, n = 18). BHI was significantly reduced in AD and aMCI patients compared to SCI subjects. A highly significant inverse correlation was found between BHI and the centiloid score (r = -0.648, p < 0.001). There was moderate positive correlation between BHI and frontal, temporal and parietal FDG SUV and ASL values, and a borderline negative correlation with age and white matter lesion volume. The link between amyloid burden and VMR was independent and strong in linear regression models where all these parameters were included (ß from -0.580 to -0.476, p < 0.001). In conclusion, our study confirms the negative association of cerebral amyloid accumulation and vasomotor reactivity in Alzheimer's disease with the most direct data to date in humans.

Proposal for the standardisation of multi-centre trials in nuclear medicine imaging: prerequisites for a European 123I-FP-CIT SPECT database.

PURPOSE: Multi-centre trials are an important part of proving the efficacy of procedures, drugs and interventions. Imaging components in such trials are becoming increasingly common; however, without sufficient control measures the usefulness of these data can be compromised. This paper describes a framework for performing high-quality multi-centre trials with single photon emission computed tomography (SPECT), using a pan-European initiative to acquire a normal control dopamine transporter brain scan database as an example. METHODS: A framework to produce high-quality and consistent SPECT imaging data was based on three key areas: quality assurance, the imaging protocol and system characterisation. Quality assurance was important to ensure that the quality of the equipment and local techniques was good and consistently high; system characterisation helped understand and where possible match the performance of the systems involved, whereas the imaging protocol was designed to allow a degree of flexibility to best match the characteristics of each imaging device. RESULTS: A total of 24 cameras on 15 sites from 8 different manufacturers were evaluated for inclusion in our multi-centre initiative. All results matched the required level of specification and each had their performance characterised. Differences in performance were found between different system types and cameras of the same type. Imaging protocols for each site were modified to match their individual characteristics to produce comparable high-quality SPECT images. CONCLUSION: A framework has been designed to produce high-quality data for multi-centre SPECT studies. This framework has been successfully applied to a pan-European initiative to acquire a healthy control dopamine transporter image database.

What is New in Nuclear Medicine Imaging for Dementia.

Advances in the molecular biology, pathology and genetics of Alzheimer's disease (AD) and other degenerative dementias have led to the development of biomarkers specific to these diseases and radiotracers that are used in nuclear medicine. Imaging and non-imaging markers have enabled very early recognition of these diseases and have caused significant changes in their definitions. Amyloid positron emission tomography (PET) and tau PET, which are molecular imaging methods, [F18]fluorodeoxyglucose (FDG) PET showing the glucose metabolism pattern in the brain, dopamine transporter single photon emission computerized tomography (SPECT) that marks dopaminergic terminals are valuable tools for early recognition and differentiation of AD and its atypical variants, frontotemporal dementias and dementia with Lewy bodies. These imaging methods, which have different advantages over each other, have different indications for use and sometimes provide complementary information. In addition, research on radiotracers targeting neuroinflammation, astrocytes, synaptic density, and cholinergic terminals is ongoing. In this review, routinely used and newly developed nuclear imaging methods in AD and other neurodegenerative dementias, the agents used and their diagnostic features will be presented together with case examples.

Prognostic value of fluorodeoxyglucose positron emission tomography derived metabolic parameters and textural features in pediatric sarcoma.

PURPOSE: The aim of this study was to evaluate the prognostic value of PET-derived metabolic features and textural parameters of primary tumors in pediatric sarcoma patients. METHODS: The imaging findings of 43 patients (14 girls and 29 boys; age 11.4 ± 4.4 years) who underwent 18-fluorodeoxyglucose positron emission tomography (PET)/computed tomography for primary staging prior to therapy between 2005 and 2020 were retrospectively evaluated. The diagnoses were osteosarcoma in 10, rhabdomyosarcoma in 10, and Ewing sarcoma in 23 patients. PET metabolic data and textural features of primary tumors were obtained. Cox proportional hazards regression models were used to identify predictors for progression-free survival and overall survival. Survival curves were estimated by using the Kaplan-Meier method. RESULTS: Distant metastases were detected in primary staging in 13 patients (30.2%). The median follow-up duration after diagnosis was 28 months (range: 10-171 months). In multivariate Cox regression analysis, the presence of distant metastasis and neighborhood grey-level difference matrix_Contrast (ngldm_Contrast) were found as independent predictors for both progression-free survival and overall survival. Grey-level zone length matrix_Zone-length nonuniformity (glzlm_ZLNU) was also found as an independent predictor for overall survival. The Kaplan-Meier survival analysis showed that higher ngldm_Contrast and glzlm_ZLNU values of primary tumors were significantly associated with shorter progression-free survival and overall survival. CONCLUSION: In addition to the presence of distant metastasis at initial diagnosis, textural features of primary tumors may be used as prognostic biomarkers to identify patients with worse prognosis in pediatric sarcoma. Higher tumor heterogeneity is significantly associated with shorter progression-free survival and OS.

Texture features of primary tumor on 18F-FDG PET images in non-small cell lung cancer: The relationship between imaging and histopathological parameters.

PURPOSE: The aims of this study were to evaluate the relationships between textural features of the primary tumor on FDG PET images and clinical-histopathological parameters which are useful in predicting prognosis in newly diagnosed non-small cell lung cancer (NSCLC) patients. METHODS: PET/CT images of ninety (90) patients with NSCLC prior to surgery were analyzed retrospectively. All patients had resectable tumors. From the images we acquired data related to metabolism (SUVmax, MTV, TLG) and texture features of primary tumors. Histopathological tumor types and subgroups, degree of Ki-67 expression and necrosis rates of the primary tumor, mediastinal lymph node (MLN) status and nodal stages were recorded. RESULTS: Among the two histologic tumor types (adenocarcinoma and squamous cell carcinoma) significant differences were present regarding metabolic parameters, Ki-67 index with higher values and kurtosis with lower values in the latter group. Textural heterogeneity was found to be higher in poorly differentiated tumors compared to moderately differentiated tumors in patients with adenocarcinoma. While Ki-67 index had significant correlations with metabolic parameters and kurtosis, tumor necrosis rate was only significantly correlated with textural features. By univariate and multivariate analyses of the imaging and histopathological factors examined, only gradient variance was significant predictive factor for the presence of MLN metastasis. CONCLUSIONS: Textural features had significant associations with histologic tumor types, degree of pathological differentiation, tumor proliferation and necrosis rates. Texture analysis has potential to differentiate tumor types and subtypes and to predict MLN metastasis in patients with NSCLC.