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[en] To determine association of body composition measurements on CT and PET with progression of smoldering myeloma to multiple myeloma. A retrospective cohort study in 65 patients with smoldering myeloma and PET/CT at diagnosis was performed at a tertiary cancer center. Subjects were between 38 and 87 years of age (mean 64) and included 37 males. Primary outcome was progression-free survival as a function of bone, fat, and muscle metrics on CT and PET (measured at the level of L4 pedicles) and clinical confounders. CT metrics included attenuation of L4 and retroperitoneal fat and various indices derived from the psoas muscle. PET measures included SUV and SUV of L4, retroperitoneal fat, and psoas. Cox proportional hazards modeling was performed with entry and retention criteria of p < 0.1 and p < 0.05, respectively. SUV and SUV were associated for each compartment (R = 0.78–0.84), and SUV (SUV) was used for subsequent analyses. SUV of the L4 vertebral body was associated with attenuation of the L4 vertebral body (p = 0.0032). There was no association between SUV and CT for muscle and fat compartments. In the subset of patients with bone marrow biopsy results (n = 43), there was no association between SUV of L4 and plasma cell concentration on core biopsy or flow cytometry (p = 0.089 and 0.072, respectively). The final Cox model showed association with albumin (HR 0.29, 95%CI 0.088–0.93, p = 0.038), M protein (HR 1.31, 95%CI 1.021–1.68, p = 0.034), and SUV of L4 (HR 1.99, 95%CI 1.037–3.82, p = 0.039). SUV of L4 is a prognostic indicator in patients with smoldering myeloma.
[en] To determine the value of chest and skeletal staging in patients presenting with conventional chondrosarcoma (CS). Retrospective review of patients with CS diagnosed between January 2007 and December 2019. Data collected included age, sex, skeletal location and results of chest CT and whole-body bone scintigraphy (WB-BSc) obtained at initial diagnosis. The histological tumour grade based on surgical resection or needle biopsy was classified as low-grade (LGCT), high-grade (HGCT) and dedifferentiated (DD-CS). Findings of chest CT and WB-BSc were correlated with tumour grade. Four hundred twenty patients were included (234 males and 186 females with mean age 54.5 years, range 9–91 years). The major long bones were involved in 205 cases, the flat bones in 166 cases, the mobile spine in 14 cases and the small bones of the hands and feet in 35 cases. Three hundred fifty tumours were central in location, 39 peripheral and 31 on the surface of the bone. There were 151 LGCTs, 196 HGCTs and 73 DD-CSs. Of patients with LGCT, 41.7% underwent chest CT and 25.2% WB-BSc. Of patients with HGCT, 95.4% underwent chest CT and 76.5% WB-BSc. Of patients with DD-CS, 98.6% underwent chest CT and 86.3% WB-BSc. Metastases were diagnosed in 2 (3.3%) chest CT studies and 0 WB-BSc in LGCT, in 8 (4.3%) chest CT studies and 0 WB-BSc in HGCT and in 21 (30%) chest CT studies and 6 (21%) WB-BSc in DD-CS. Staging chest CT and WB-BSc is of little or no value except in DD-CS.
[en] Myositis ossificans (MO) is a benign soft-tissue lesion characterized by the heterotopic formation of the bone in skeletal muscles, usually due to trauma. MO is occasionally difficult to diagnose because of its clinical and radiological similarities with malignancy. We report a case of traumatic MO (TMO) in the masseter and brachial muscles of a 37-year-old man who presented with painless swelling in the left cheek and severe trismus. Due to the absence of a traumatic history at the first consultation and identification of a tumorous lesion in the left masseter muscle by magnetic resonance imaging (MRI), the lesion was suspected to be a malignant tumor. Subsequently, 18F-fluorodeoxyglucose positron-emission tomography/computed tomography (FDG-PET/CT) showed multiple regions of high FDG uptake across the whole body, suggestive of multiple metastases or other systemic diseases. However, intramuscular calcifications were also observed in the left masseter and brachial muscles, overlapping the areas with high FDG uptake. Moreover, multiple fractures were seen in the rib and lumbar spine, also overlapping the areas with high FDG uptake. Based on these imaging findings, along with a history of jet-ski trauma, TMO was suspected. The left cheek mass was surgically excised and histologically diagnosed as TMO. In this case report, FDG-PET/CT could detect multiple TMOs across the whole body. To the best of our knowledge, cases of multiple TMOs located far apart in different muscles are rare, and this may be the first report.
[en] This study aimed to investigate the deep learning model (DLM) combining computed tomography (CT) images and clinicopathological information for predicting anaplastic lymphoma kinase (ALK) fusion status in non-small cell lung cancer (NSCLC) patients. Preoperative CT images, clinicopathological information as well as the ALK fusion status from 937 patients in three hospitals were retrospectively collected to train and validate the DLM for the prediction of ALK fusion status in tumors. Another cohort of patients (n = 91) received ALK tyrosine kinase inhibitor (TKI) treatment was also included to evaluate the value of the DLM in predicting the clinical outcomes of the patients. The performances of the DLM trained only by CT images in the primary and validation cohorts were AUC = 0.8046 (95% CI 0.7715–0.8378) and AUC = 0.7754 (95% CI 0.7199–0.8310), respectively, while the DLM trained by both CT images and clinicopathological information exhibited better performance for the prediction of ALK fusion status (AUC = 0.8540, 95% CI 0.8257–0.8823 in the primary cohort, p < 0.001; AUC = 0.8481, 95% CI 0.8036–0.8926 in the validation cohort, p < 0.001). In addition, the deep learning scores of the DLMs showed significant differences between the wild-type and ALK infusion tumors. In the ALK-target therapy cohort (n = 91), the patients predicted as ALK-positive by the DLM showed better performance of progression-free survival than the patients predicted as ALK-negative (16.8 vs. 7.5 months, p = 0.010). Our findings showed that the DLM trained by both CT images and clinicopathological information could effectively predict the ALK fusion status and treatment responses of patients. For the small size of the ALK-target therapy cohort, larger data sets would be collected to further validate the performance of the model for predicting the response to ALK-TKI treatment.
[en] The accurate detection of nodal invasion is an unmet need in the clinical staging of renal cancer. Positron emission tomography (PET) with 18F-fluoroazomycin arabinoside (18F-FAZA), a hypoxia specific tracer, is a non-invasive imaging method that detects tumour hypoxia. The aim of this work was to evaluate the role of 18F-FAZA PET/CT in the identification of lymph node metastases in renal cancer. A proof-of-concept phase 2 study including 20 kidney cancer patients (ClinicalTrials.gov Identifier: NCT03955393) was conducted. Inclusion criteria were one or more of the following three criteria: (1) clinical tumour size > 10 cm, (2) evidence of clinical lymphadenopathies at preoperative CT scan and (3) clinical T4 cancer. Before surgery, 18F-FAZA PET/CT was performed, 2 h after the intravenous injection of the radiotracer. An experienced nuclear medicine physician, aware of patient’s history and of all available diagnostic imaging, performed a qualitative and semi-quantitative analysis on 18F-FAZA images. Histopathological analysis was obtained in all patients on surgical specimen. Fourteen/19 (74%) patients had a non-organ confined renal cell carcinoma (RCC) at final pathology (either pT3 or pT4). Median number of nodes removed was 12 (IQR 7–15). The rate of lymph node invasion was 16%. No patient with pN1 disease showed positive 18F-FAZA PET, thus suggesting the non-hypoxic behaviour of the lesions. In addition, neither primary tumour nor distant metastases presented a pathological 18F-FAZA uptake. No adverse events were recorded during the study. 18F-FAZA PET/CT scan did not detect RCC lymph neither nodal nor distant metastases and did not show any uptake in the primary renal tumour.
[en] A unique experimental setup at the Accelerator Laboratory of the University of Helsinki enables in situ positron annihilation spectroscopy (PAS) analysis on ion irradiated samples. In addition, the system enables temperature control (10-300 K) of the sample both during irradiation and during subsequent positron annihilation measurements. Using such a system for defect identification and annealing studies comes with a plethora of possibilities for elaborate studies. However, the system also poses some restrictions and challenges to these possibilities, both related to irradiation and to the PAS analysis. This review tries to address these issues. (© 2020 The Authors. Published by Wiley‐VCH GmbH)
[en] This work investigates the interface properties of intrinsic hydrogenated amorphous silicon film passivated wafers that underwent hydrogen plasma cleaning. A high level of interface band bending of nearly -0.6 eV, which corresponds to a fixed charge of -2.2 × 10 cm, is found to be responsible for an effective minority carrier lifetime of over 6 ms on the 4.5 Ω cm n-type wafer, while such field-effect passivation is missing in hydrofluoric acid (HF) cleaned wafers. Further study indicates a positive correlation between the extent of surface band bending and doping concentration, together with an inverted U-shape with respect to the increased annealing condition. The fixed charge on p-type wafer is found to have a higher ''formation energy'' compared with the n-type case, which renders its field-effect passivation much less effective due to H effusion at high annealing temperatures. With reference to the theory on donor/acceptor-H complex upon H plasma treatment, the origin and observed properties of the surface band bending on both dopant types are discussed. The unique presence of field effect on hydrogen plasma cleaned n-type wafers can provide new insights into passivation material selection and structural design of heterojunction silicon wafer solar cells. (© 2020 Wiley‐VCH GmbH)
[en] To evaluate the feasibility and sensitivity of multimodality PET/CT and MRI imaging for non-invasive characterization of brain microglial/macrophage activation occurring during the acute phase in a mouse model of relapsing remitting multiple sclerosis (RR-MS) using [F]DPA-714, a selective radioligand for the 18-kDa translocator protein (TSPO), superparamagnetic iron oxide particles (SPIO), and ex vivo immunohistochemistry. Experimental autoimmune encephalomyelitis (EAE) was induced in female SJL/J mice by immunization with PLP. Seven symptomatic EAE mice and five controls underwent both PET/CT and MRI studies between 11 and 14 days post-immunization. SPIO was injected i.v. in the same animals immediately after [F]DPA-714 and MRI acquisition was performed after 24 h. Regional brain volumes were defined according to a mouse brain atlas on co-registered PET and SPIO-MRI images. [F]DPA-714 standardized uptake value (SUV) ratios (SUVR), with unaffected neocortex as reference, and SPIO fractional volumes (SPIO-Vol) were generated. Both SUVR and SPIO-Vol values were correlated with the clinical score (CS) and among them. Five EAE and four control mice underwent immunohistochemical analysis with the aim of identifying activated microglia/macrophage and TSPO expressions. SUVR and SPIO-Vol values were significantly increased in EAE compared with controls in the hippocampus (p < 0.01; p < 0.02, respectively), thalamus (p < 0.02; p < 0.05, respectively), and cerebellum and brainstem (p < 0.02), while only SPIO-Vol was significantly increased in the caudate/putamen (p < 0.05). Both SUVR and SPIO-Vol values were positively significantly correlated with CS and among them in the same regions. TSPO/Iba1 and F4/80/Prussian blue staining immunohistochemistry suggests that increased activated microglia/macrophages underlay TSPO expression and SPIO uptake in symptomatic EAE mice. These preliminary results suggest that both activated microglia and infiltrated macrophages are present in vulnerable brain regions during the acute phase of PLP-EAE and contribute to disease severity. Both [F]DPA-714-PET and SPIO-MRI appear suitable modalities for preclinical study of neuroinflammation in MS mice models.
[en] This prospective study aimed to evaluate the potential usefulness of [Ga]Ga-DOTA-FAPI-04 positron emission tomography/computed tomography (PET/CT) in the oncological evaluation of patients presenting with inconclusive [F]FDG PET/CT findings. [Ga]Ga-DOTA-FAPI-04 was performed in patients presenting with inconclusive [F]FDG PET/CT findings. Tumour uptake was quantified by the maximum standard uptake value (SUV). Histopathology or follow-up imaging served as the standard for the final diagnosis. A total of 68 patients with inconclusive [F]FDG PET/CT findings underwent additional [Ga]Ga-DOTA-FAPI-04 PET/CT. Of them, 18 (26.5%) were for discrimination of mass lesions detected on conventional imaging, 6 (8.8%) for detection of the unknown primary site in biopsy-proven metastatic malignancy, 21 (30.9%) for the staging of cancer, and the other 23 (33.8%) for evaluation of suspected disease recurrence. Most of the primary and metastatic lesions demonstrated higher uptake of [Ga]Ga-DOTA-FAPI-04 than did [F]FDG, which resulted in favourable tumour-to-background contrast in various types of cancer. As a result, [Ga]Ga-DOTA-FAPI-04 PET/CT identified suspicious mass lesions with an accuracy of 12/18 (66.7%), detected the primary site in 4/6 patients (66.7%) with unknown malignancy, upgraded tumour staging in 7/21 patients (33.3%), and detected disease recurrence in 20/23 patients (87.0%). In patients undergoing oncological evaluation with inconclusive [F]FDG PET/CT findings, [Ga]Ga-DOTA-FAPI-04 may have a complementary role in discriminating mass lesions on conventional imaging, locating the primary site of unknown malignancy, modifying tumour staging, and detecting suspected disease recurrence. Nevertheless, careful attention should be paid when reading the [Ga]Ga-DOTA-FAPI-04 PET/CT images in tumours complicated with inflammation.