A Short Dynamic Scan Method of Measuring Bone Metabolic Flux Using [F]NaF PET.

[F]NaF PET measurements of bone metabolic flux (K) are conventionally obtained with 60-min dynamic scans analysed using the Hawkins model. However, long scan times make this method expensive and uncomfortable for subjects. Therefore, we evaluated and compared measurements of K with shorter scan times analysed with fixed values of the Hawkins model rate constants.

Teriparatide Promotes Bone Healing in Medication-Related Osteonecrosis of the Jaw: A Placebo-Controlled, Randomized Trial.

Purpose: Medication-related osteonecrosis of the jaw (MRONJ) is an infrequent but morbid and potentially serious condition associated with antiresorptive and antiangiogenic therapies. Although MRONJ can be prevented by optimizing oral health, management of established cases is supportive and remains challenging. Teriparatide, an osteoanabolic agent that improves bone healing in preclinical studies and in chronic periodontitis, represents a potential treatment option.

Artificial intelligence in medical imaging: A radiomic guide to precision phenotyping of cardiovascular disease.

Rapid technological advances in non-invasive imaging, coupled with the availability of large data sets and the expansion of computational models and power, have revolutionized the role of imaging in medicine. Non-invasive imaging is the pillar of modern cardiovascular diagnostics, with modalities such as cardiac computed tomography (CT) now recognized as first-line options for cardiovascular risk stratification and the assessment of stable or even unstable patients. To date, cardiovascular imaging has lagged behind other fields, such as oncology, in the clinical translational of artificial intelligence (AI)-based approaches.

The influence of CT and dual-energy X-ray absorptiometry (DXA) bone density on quantitative [F] sodium fluoride PET.

Background: [F] sodium fluoride PET/CT provides quantitative measures of bone metabolic activity expressed by the parameters standardised uptake value (SUV) and bone plasma clearance ( ) that correlate with measurements of bone formation rate obtained by bone biopsy with double tetracycline labelling. Both SUV and relate to the tracer uptake in each millilitre of tissue. In general, the bone region of interest (ROI) includes both mineralised bone {generally with a high concentration of [F]NaF} and bone marrow (with a much lower concentration), suggesting that correcting SUV and for volumetric bone mineral density (vBMD) and measuring them with respect to the tracer uptake in each gram of bone mineral might improve the correlation with the findings of bone biopsy.

Radiomics in esophageal and gastric cancer.

Esophageal, esophago-gastric, and gastric cancers are major causes of cancer morbidity and cancer death. For patients with potentially resectable disease, multi-modality treatment is recommended as it provides the best chance of survival. However, quality of life may be adversely affected by therapy, and with a wide variation in outcome despite multi-modality therapy, there is a clear need to improve patient stratification.

Is Response Assessment of Breast Cancer Bone Metastases Better with Measurement of F-Fluoride Metabolic Flux Than with Measurement of F-Fluoride PET/CT SUV?

Our purpose was to establish whether noninvasive measurement of changes in F-fluoride metabolic flux to bone mineral (K) by PET/CT can provide incremental value in response assessment of bone metastases in breast cancer compared with SUV and SUV Twelve breast cancer patients starting endocrine treatment for de novo or progressive bone metastases were included. Static F-fluoride PET/CT scans were acquired 60 min after injection, before and 8 wk after commencing treatment. Venous blood samples were taken at 55 and 85 min after injection to measure plasma F-fluoride activity concentrations, and K in individual bone metastases was calculated using a previously validated method.

Site specific measurements of bone formation using [F] sodium fluoride PET/CT.

Dynamic positron emission tomography (PET) imaging with fluorine-18 labelled sodium fluoride ([F]NaF) allows the quantitative assessment of regional bone formation by measuring the plasma clearance of fluoride to bone at any site in the skeleton. Today, hybrid PET and computed tomography (CT) dual-modality systems (PET/CT) are widely available, and [F]NaF PET/CT offers a convenient non-invasive method of studying bone formation at the important osteoporotic fracture sites at the hip and spine, as well as sites of pure cortical or trabecular bone. The technique complements conventional measurements of bone turnover using biochemical markers or bone biopsy as a tool to investigate new therapies for osteoporosis, and has a potential role as an early biomarker of treatment efficacy in clinical trials.

Challenges and Promises of PET Radiomics.

Purpose: Radiomics describes the extraction of multiple, otherwise invisible, features from medical images that, with bioinformatic approaches, can be used to provide additional information that can predict underlying tumor biology and behavior.

Methods And Materials: Radiomic signatures can be used alone or with other patient-specific data to improve tumor phenotyping, treatment response prediction, and prognosis, noninvasively. The data describing F-fluorodeoxyglucose positron emission tomography radiomics, often using texture or heterogeneity parameters, are increasing rapidly.

Primary Rectal Cancer: Repeatability of Global and Local-Regional MR Imaging Texture Features.

Purpose To assess the day-to-day repeatability of global and local-regional magnetic resonance (MR) imaging texture features derived from primary rectal cancer. Materials and Methods After ethical approval and patient informed consent were obtained, two pretreatment T2-weighted axial MR imaging studies performed prospectively with the same imaging unit on 2 consecutive days in 14 patients with rectal cancer (11 men [mean age, 61.7 years], three women [mean age, 70.

Magnetic Resonance Imaging (MRI) of Intratumoral Voxel Heterogeneity as a Potential Response Biomarker: Assessment in a HER2+ Esophageal Adenocarcinoma Xenograft Following Trastuzumab and/or Cisplatin Therapy.

We evaluated magnetic resonance imaging (MRI) voxel heterogeneity following trastuzumab and/or cisplatin in a HER2+ esophageal xenograft (OE19) as a potential response biomarker. OE19 xenografts treated with saline (controls), monotherapy, or combined cisplatin and trastuzumab underwent 9.4-T MRI.

The effect of post-injection F-FDG PET scanning time on texture analysis of peripheral nerve sheath tumours in neurofibromatosis-1.

Background: Texture features are being increasingly evaluated in F-fluorodeoxyglucose positron emission tomography (F-FDG PET) as adjunctive imaging biomarkers in a number of different cancers. Whilst studies have reported repeatability between scans, there have been no studies that have specifically investigated the effect that the time of acquisition post-injection of F-FDG has on texture features. The aim of this study was to investigate if texture features change between scans performed at different time points post-injection.

Predicting Response to Neoadjuvant Chemotherapy with PET Imaging Using Convolutional Neural Networks.

Imaging of cancer with 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) has become a standard component of diagnosis and staging in oncology, and is becoming more important as a quantitative monitor of individual response to therapy. In this article we investigate the challenging problem of predicting a patient's response to neoadjuvant chemotherapy from a single 18F-FDG PET scan taken prior to treatment. We take a "radiomics" approach whereby a large amount of quantitative features is automatically extracted from pretherapy PET images in order to build a comprehensive quantification of the tumor phenotype.

Imaging Tumor Response and Tumoral Heterogeneity in Non-Small Cell Lung Cancer Treated With Antiangiogenic Therapy: Comparison of the Prognostic Ability of RECIST 1.1, an Alternate Method (Crabb), and Image Heterogeneity Analysis.

Purpose: We aimed to assess computed tomography (CT) intratumoral heterogeneity changes, and compared the prognostic ability of the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, an alternate response method (Crabb), and CT heterogeneity in non-small cell lung cancer treated with chemotherapy with and without bevacizumab.

Materials And Methods: Forty patients treated with chemotherapy (group C) or chemotherapy and bevacizumab (group BC) underwent contrast-enhanced CT at baseline and after 1, 3, and 6 cycles of chemotherapy.

Imaging body composition in cancer patients: visceral obesity, sarcopenia and sarcopenic obesity may impact on clinical outcome.

Unlabelled: In recent years, there has been increasing interest in the influence of body composition on oncological patient outcomes. Visceral obesity, sarcopenia and sarcopenic obesity have been identified as adverse factors in cancer patients. Imaging quantification of body composition such as lean muscle mass and fat distribution is a potentially valuable tool.

The precision of textural analysis in (18)F-FDG-PET scans of oesophageal cancer.

Objectives: Measuring tumour heterogeneity by textural analysis in (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) provides predictive and prognostic information but technical aspects of image processing can influence parameter measurements. We therefore tested effects of image smoothing, segmentation and quantisation on the precision of heterogeneity measurements.

Methods: Sixty-four (18)F-FDG PET/CT images of oesophageal cancer were processed using different Gaussian smoothing levels (2.

Correction of the slope-intercept method for the measurement of glomerular filtration rate.

Objective: Glomerular filtration rate (GFR) is frequently assessed using the slope-intercept method by fitting a single exponential to plasma samples obtained 2-5 h after injection. The body surface area (BSA)-corrected one-pool clearance (CO,BSA) overestimates true GFR (CT,BSA) because it fails to sample the full plasma curve, and values of CT,BSA are usually estimated from CO,BSA using the Brøchner-Mortensen (BM) equation. An improved equation, CT,BSA=CO,BSA/(1+fBSA×CO,BSA), with fBSA a fixed constant, was proposed by Fleming, but subsequently Jødal and Brøchner-Mortensen (JBM) reported that fBSA varies with BSA.

Imaging of site specific bone turnover in osteoporosis using positron emission tomography.

The functional imaging technique of dynamic fluorine-18 labeled sodium fluoride positron emission tomography ((18)F-NaF PET) allows the quantitative assessment of regional bone formation by measuring the plasma clearance of fluoride to bone at any site in the skeleton. (18)F-NaF PET provides a novel and noninvasive method of studying site-specific bone formation at the hip and spine, as well as areas of pure cortical or trabecular bone. The technique complements conventional measurements of bone turnover using biochemical markers and bone biopsy as a tool to investigate new treatments for osteoporosis, and holds promise of a future role as an early biomarker of treatment efficacy in clinical trials.

Correcting (18)F-fluoride PET static scan measurements of skeletal plasma clearance for tracer efflux from bone.

Objective: The aim of the study was to examine whether (18)F-fluoride PET ((18)F-PET) static scan measurements of bone plasma clearance (Ki) can be corrected for tracer efflux from bone from the time of injection.

Materials And Methods: The efflux of tracer from bone mineral to plasma was described by a first-order rate constant kloss. A modified Patlak analysis was applied to 60-min dynamic (18)F-PET scans of the spine and hip acquired during trials on the bone anabolic agent teriparatide to find the best-fit values of kloss at the lumbar spine, total hip and femoral shaft.

(18)F-fluoride positron emission tomography measurements of regional bone formation in hemodialysis patients with suspected adynamic bone disease.

(18)F-fluoride positron emission tomography ((18)F-PET) allows the assessment of regional bone formation and could have a role in the diagnosis of adynamic bone disease (ABD) in patients with chronic kidney disease (CKD). The purpose of this study was to examine bone formation at multiple sites of the skeleton in hemodialysis patients (CKD5D) and assess the correlation with bone biopsy. Seven CKD5D patients with suspected ABD and 12 osteoporotic postmenopausal women underwent an (18)F-PET scan, and bone plasma clearance, K i, was measured at ten skeletal regions of interest (ROI).

¹⁸F-fluoride PET as a noninvasive imaging biomarker for determining treatment efficacy of bone active agents at the hip: a prospective, randomized, controlled clinical study.

The functional imaging technique of ¹⁸F-fluoride positron emission tomography (¹⁸F-PET) allows the noninvasive quantitative assessment of regional bone formation at any skeletal site, including the spine and hip. The aim of this study was to determine if ¹⁸F-PET can be used as an early biomarker of treatment efficacy at the hip. Twenty-seven treatment-naive postmenopausal women with osteopenia were randomized to receive teriparatide and calcium and vitamin D (TPT group, n = 13) or calcium and vitamin D only (control group, n = 14).

Quantifying tumour heterogeneity in 18F-FDG PET/CT imaging by texture analysis.

(18)F-Fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) is now routinely used in oncological imaging for diagnosis and staging and increasingly to determine early response to treatment, often employing semiquantitative measures of lesion activity such as the standardized uptake value (SUV). However, the ability to predict the behaviour of a tumour in terms of future therapy response or prognosis using SUVs from a baseline scan prior to treatment is limited. It is recognized that medical images contain more useful information than may be perceived with the naked eye, leading to the field of "radiomics" whereby additional features can be extracted by computational postprocessing techniques.

Quantitative PET Imaging Using (18)F Sodium Fluoride in the Assessment of Metabolic Bone Diseases and the Monitoring of Their Response to Therapy.

Studies of bone remodeling using bone biopsy and biochemical markers of bone turnover measured in serum and urine are important for investigating how new treatments for osteoporosis affect bone metabolism. Positron emission tomography with (18)F sodium fluoride ((18)F NaF PET) for studying bone metabolism complements these conventional methods. Unlike biochemical markers, which measure the integrated response to treatment across the whole skeleton, (18)F NaF PET can distinguish changes occurring at sites of clinically important osteoporotic fractures.

A semipopulation input function for quantifying static and dynamic 18F-fluoride PET scans.

Purpose: We describe a semipopulation input function for evaluating bone plasma clearance from static and dynamic (18)F-fluoride PET scans.

Methods: The semipopulation input function was derived by fitting an exponential curve to venous plasma measurements obtained 30-60 min after injection and adding a population residual curve representing the bolus peak scaled for injected activity and adjusted for time of peak counts. The residual curve was found from nine postmenopausal women who had continuous arterial blood samples and venous samples taken every 10 min.

Comparison of six quantitative methods for the measurement of bone turnover at the hip and lumbar spine using 18F-fluoride PET-CT.

Aim: The aim of this study was to evaluate the relationship between different quantification methods used for the measurement of bone plasma clearance (K(i)) using F-PET at the hip and lumbar spine.

Methods: Twelve healthy postmenopausal women aged 52-71 years were recruited. Each participant underwent 60-min dynamic F-PET scans at the lumbar spine and hip on two separate occasions with an injected activity of 90 and 180 MBq, respectively.