Training on reporting and data system (RADS) for somatostatin-receptor targeted molecular imaging can reduce the test anxiety of inexperienced readers

PURPOSE: For somatostatin receptor (SSTR)-positron emission tomography/computed tomography (PET/CT), a standardized framework termed SSTR-reporting and data system (RADS) has been proposed. We aimed to elucidate the impact of a RADS-focused training on reader’s anxiety to report on SSTR-PET/CT, the motivational beliefs in learning such a system, whether it increases reader’s confidence, and its implementation in clinical routine. PROCEDURES: A 3-day training course focusing on SSTR-RADS was conducted. Self-report questionnaires were handed out prior to the course (Pre) and thereafter (Post). The impact of the training on the following categories was evaluated: (1) test anxiety to report on SSTR-PET/CT, (2) motivational beliefs, (3) increase in reader’s confidence, and (4) clinical implementation. To assess the effect size of the course, Cohen’s d was calculated (small, d = 0.20; large effect, d = 0.80). RESULTS: Of 22 participants, Pre and Post were returned by 21/22 (95.5%). In total, 14/21 (66.7%) were considered inexperienced (IR,  1 year). Applying SSTR-RADS, a large decrease in anxiety to report on SSTR-PET/CT was noted for IR (d =  − 0.74, P = 0.02), but not for ER (d = 0.11, P = 0.78). For the other three categories motivational beliefs, reader’s confidence, and clinical implementation, agreement rates were already high prior to the training and persisted throughout the course (P ≥ 0.21). CONCLUSIONS: A framework-focused reader training can reduce anxiety to report on SSTR-PET/CTs, in particular for inexperienced readers. This may allow for a more widespread adoption of this system, e.g., in multicenter trials for better intra- and interindividual comparison of scan results. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11307-022-01712-6

Consensus-based technical recommendations for clinical translation of renal ASL MRI

OBJECTIVES: This study aimed at developing technical recommendations for the acquisition, processing and analysis of renal ASL data in the human kidney at 1.5 T and 3 T field strengths that can promote standardization of renal perfusion measurements and facilitate the comparability of results across scanners and in multi-centre clinical studies. METHODS: An international panel of 23 renal ASL experts followed a modified Delphi process, including on-line surveys and two in-person meetings, to formulate a series of consensus statements regarding patient preparation, hardware, acquisition protocol, analysis steps and data reporting. RESULTS: Fifty-nine statements achieved consensus, while agreement could not be reached on two statements related to patient preparation. As a default protocol, the panel recommends pseudo-continuous (PCASL) or flow-sensitive alternating inversion recovery (FAIR) labelling with a single-slice spin-echo EPI readout with background suppression and a simple but robust quantification model. DISCUSSION: This approach is considered robust and reproducible and can provide renal perfusion images of adequate quality and SNR for most applications. If extended kidney coverage is desirable, a 2D multislice readout is recommended. These recommendations are based on current available evidence and expert opinion. Nonetheless they are expected to be updated as more data become available, since the renal ASL literature is rapidly expanding

Lack of repeatability of radiomic features derived from PET scans: results from a 18F‐DCFPyL test–retest cohort

Objectives PET-based radiomic metrics are increasingly utilized as predictive image biomarkers. However, the repeatability of radiomic features on PET has not been assessed in a test–retest setting. The prostate-specific membrane antigen-targeted compound 18F-DCFPyL is a high-affinity, high-contrast PET agent that we utilized in a test-retest cohort of men with metastatic prostate cancer (PC). Methods Data of 21 patients enrolled in a prospective clinical trial with histologically proven PC underwent two 18F-DCFPyL PET scans within 7 days, using identical acquisition and reconstruction parameters. Sites of disease were segmented and a set of 29 different radiomic parameters were assessed on both scans. We determined repeatability of quantification by using Pearson's correlations, within-subject coefficient of variation (wCOV), and Bland–Altman analysis. Results In total, 230 lesions (177 bone, 38 lymph nodes, 15 others) were assessed on both scans. For all investigated radiomic features, a broad range of inter-scan correlation was found (r, 0.07–0.95), with acceptable reproducibility for entropy and homogeneity (wCOV, 16.0% and 12.7%, respectively). On Bland–Altman analysis, no systematic increase or decrease between the scans was observed for either parameter (±1.96 SD: 1.07/−1.30, 0.23/−0.18, respectively). The remaining 27 tested radiomic metrics, however, achieved unacceptable high wCOV (≥21.7%). Conclusion Many common radiomic features derived from a test–retest PET study had poor repeatability. Only Entropy and homogeneity achieved good repeatability, supporting the notion that those image biomarkers may be incorporated in future clinical trials. Those radiomic features based on high frequency aspects of images appear to lack the repeatability on PET to justify further study

High SUVs have more robust repeatability in patients with metastatic prostate cancer: results from a prospective test-retest cohort imaged with 18F-DCFPyL

OBJECTIVES: In patients with prostate cancer (PC) receiving prostate-specific membrane antigen- (PSMA-) targeted radioligand therapy (RLT), higher baseline standardized uptake values (SUVs) are linked to improved outcome. Thus, readers deciding on RLT must have certainty on the repeatability of PSMA uptake metrics. As such, we aimed to evaluate the test-retest repeatability of lesion uptake in a large cohort of patients imaged with (18)F-DCFPyL. METHODS: In this prospective, IRB-approved trial (NCT03793543), 21 patients with history of histologically proven PC underwent two (18)F-DCFPyL PET/CTs within 7 days (mean 3.7, range 1 to 7 days). Lesions in the bone, lymph nodes (LN), and other organs were manually segmented on both scans, and uptake parameters were assessed (maximum (SUV(max)) and mean (SUV(mean)) SUVs), PSMA-tumor volume (PSMA-TV), and total lesion PSMA (TL-PSMA, defined as PSMA − TV × SUV(mean))). Repeatability was determined using Pearson's correlations, within-subject coefficient of variation (wCOV), and Bland-Altman analysis. RESULTS: In total, 230 pairs of lesions (177 bone, 38 LN, and 15 other) were delineated, demonstrating a wide range of SUV(max) (1.5–80.5) and SUV(mean) (1.4–24.8). Including all sites of suspected disease, SUVs had a strong interscan correlation (R(2) ≥ 0.99), with high repeatability for SUV(mean) and SUV(max) (wCOV, 7.3% and 12.1%, respectively). High SUVs showed significantly improved wCOV relative to lower SUVs (P < 0.0001), indicating that high SUVs are more repeatable, relative to the magnitude of the underlying SUV. Repeatability for PSMA-TV and TL-PSMA, however, was low (wCOV ≥ 23.5%). Across all metrics for LN and bone lesions, interscan correlation was again strong (R(2) ≥ 0.98). Moreover, LN-based SUV(mean) also achieved the best wCOV (3.8%), which was significantly reduced when compared to osseous lesions (7.8%, P < 0.0001). This was also noted for SUV(max) (wCOV, LN 8.8% vs. bone 12.0%, P < 0.03). On a compartment-based level, wCOVs for volumetric features were ≥22.8%, demonstrating no significant differences between LN and bone lesions (PSMA-TV, P =0.63; TL-PSMA, P =0.9). Findings on an entire tumor burden level were also corroborated in a hottest lesion analysis investigating the SUV(max) of the most intense lesion per patient (R(2), 0.99; wCOV, 11.2%). CONCLUSION: In this prospective test-retest setting, SUV parameters demonstrated high repeatability, in particular in LNs, while volumetric parameters demonstrated low repeatability. Further, the large number of lesions and wide distribution of SUVs included in this analysis allowed for the demonstration of a dependence of repeatability on SUV, with higher SUVs having more robust repeatability

Carotid Plaque Imaging with SPECT/CT and PET/CT

A major contributor to the occurrence of ischemic stroke is the existence of carotid atherosclerosis. A vulnerable carotid atherosclerotic plaque may rupture or erode, thus causing a thrombotic event. Currently, clinical decision-making with regard to carotid endarterectomy or stenting is still primarily based on the extent of luminal stenosis, estimated with CT angiography and/or (duplex) ultrasonography. However, there is growing evidence that the anatomic impact of stenosis alone has limited value in predicting the exact consequences of plaque vulnerability. Various molecular processes have, independently of degree of stenosis, shown to be importantly associated with the plaque's capability to cause thrombotic events. These molecular processes can be visualized with nuclear medicine techniques allowing the identification of vulnerable patients by non-invasive in vivo SPECT(/CT) and PET(/CT) imaging. This chapter provides an overview of SPECT(/CT) and PET(/CT) imaging with specific radiotracers that have been evaluated for the detection of plaques together with a future perspective in this field of imaging.</p

Skeletal muscle derived Musclin protects the heart during pathological overload

Cachexia is associated with poor prognosis in chronic heart failure patients, but the underlying mechanisms of cachexia triggered disease progression remain poorly understood. Here, we investigate whether the dysregulation of myokine expression from wasting skeletal muscle exaggerates heart failure. RNA sequencing from wasting skeletal muscles of mice with heart failure reveals a reduced expression of Ostn, which encodes the secreted myokine Musclin, previously implicated in the enhancement of natriuretic peptide signaling. By generating skeletal muscle specific Ostn knock-out and overexpressing mice, we demonstrate that reduced skeletal muscle Musclin levels exaggerate, while its overexpression in muscle attenuates cardiac dysfunction and myocardial fibrosis during pressure overload. Mechanistically, Musclin enhances the abundance of C-type natriuretic peptide (CNP), thereby promoting cardiomyocyte contractility through protein kinase A and inhibiting fibroblast activation through protein kinase G signaling. Because we also find reduced OSTN expression in skeletal muscle of heart failure patients, augmentation of Musclin might serve as therapeutic strategy

The Role of Imaging in Measuring Disease Progression and Assessing Novel Therapies in Aortic Stenosis

Aortic stenosis represents a growing health care burden in high-income countries. Currently, the only definitive treatment is surgical or transcatheter valve intervention at the end stages of disease. As the understanding of the underlying pathophysiology evolves, many promising therapies are being investigated. These seek to both slow disease progression in the valve and delay the transition from hypertrophy to heart failure in the myocardium, with the ultimate aim of avoiding the need for valve replacement in the elderly patients afflicted by this condition. Noninvasive imaging has played a pivotal role in enhancing our understanding of the complex pathophysiology underlying aortic stenosis, as well as disease progression in both the valve and myocardium. In this review, the authors discuss the means by which contemporary imaging may be used to assess disease progression and how these approaches may be utilized, both in clinical practice and research trials exploring the clinical efficacy of novel therapies