Performance Evaluation of Multiple Ultrasonographical Methods for the Detection of Primary Sjögren's Syndrome.

Major salivary gland ultrasonography (SGUS) is increasingly being recognized as having critical roles in differentiating primary Sjögren's syndrome (pSS) from other connective tissue disorders. Contrast-enhanced ultrasonography (CEUS) has been reported to evaluate microvascularity of lesions in different tissues with objective angiographic index, eliminating the observer-dependent defect of ultrasonography. However, there are few relevant studies concentrating on the application of CEUS in the diagnosis and assessment for pSS, and their clinical utility prospect remains uncertain. In this study, a total of 227 eligible patients were enrolled, including 161 pSS and 66 non-pSS patients with comprehensive ultrasonographic evaluation of the parotid and submandibular glands, including grayscale ultrasonography, color Doppler sonography (CDS), and CEUS. Compared with non-pSS, pSS patients had significantly higher grayscale ultrasound (US) scores and CDS blood grades in the parotid gland and significantly higher grayscale US and CEUS scores in the submandibular glands. Diagnostic model combining ultrasonographic signatures, anti-SSA/Ro60, and keratoconjunctivitis sicca (KCS) tests showed a remarkable discrimination [mean area under the curve (AUC)0.963 in submandibular glands and 0.934 in parotid glands] for pSS, and the nomogram provided excellent prediction accuracy and good calibration in individualized prediction of pSS. A combination of multiple ultrasonographical examinations of the major salivary glands (SGs) is a promising technique that may be used as a practical alternative to minor SG biopsy in the detection of pSS.

Biomedical Applications of Translational Optical Imaging: From Molecules to Humans.

Light is a powerful investigational tool in biomedicine, at all levels of structural organization. Its multitude of features (intensity, wavelength, polarization, interference, coherence, timing, non-linear absorption, and even interactions with itself) able to create contrast, and thus images that detail the makeup and functioning of the living state can and should be combined for maximum effect, especially if one seeks simultaneously high spatiotemporal resolution and discrimination ability within a living organism. The resulting high relevance should be directed towards a better understanding, detection of abnormalities, and ultimately cogent, precise, and effective intervention. The new optical methods and their combinations needed to address modern surgery in the operating room of the future, and major diseases such as cancer and neurodegeneration are reviewed here, with emphasis on our own work and highlighting selected applications focusing on quantitation, early detection, treatment assessment, and clinical relevance, and more generally matching the quality of the optical detection approach to the complexity of the disease. This should provide guidance for future advanced theranostics, emphasizing a tighter coupling-spatially and temporally-between detection, diagnosis, and treatment, in the hope that technologic sophistication such as that of a Mars rover can be translationally deployed in the clinic, for saving and improving lives.

Variability measurements provide additional value to shear wave elastography in the diagnosis of pancreatic cancer.

Shear wave elastography (SWE) is a technique to non-invasively and quantitatively evaluate tissue stiffness. We aimed to investigate whether we can differentiate pancreatic cancer (PC) from normal pancreatic parenchyma (NPP) by SWE using transabdominal ultrasound. We investigated a total of 106 patients (84 with NPP and 22 with PC) whose pancreatic elastic modulus was measured by two-dimensional SWE (2D-SWE). Intra-rater reliability in this study was examined, and three measurements were sufficiently reliable. There were no differences between the two groups in factors that could affect SWE measurements. The median value of the elastic modulus was 5.70 kPa in the PC patients and 5.66 kPa in the NPP group, which was not significantly different (P = 0.785). On the contrary, the range was 8.64 kPa and 4.72 kPa, with a significantly greater range in the PC patients (P = 0.001). In conclusion, the median elastic modulus measured by 2D-SWE was not significantly different between PC and NPP, and evaluating the obtained elastic modulus itself is not useful in differentiation. However, the variability was significantly greater in PC than in NPP. Evaluating the range of elasticities will provide additional information in SWE, which may be useful in the diagnosis of PC.

Multi-modal imaging of high-risk ductal carcinoma in situ of the breast using C2Am: a targeted cell death imaging agent.

BACKGROUND: Ductal carcinoma in situ (DCIS) is a non-invasive form of early breast cancer, with a poorly understood natural history of invasive transformation. Necrosis is a well-recognized adverse prognostic feature of DCIS, and non-invasive detection of its presence and spatial extent could provide information not obtainable by biopsy. We describe here imaging of the distribution and extent of comedo-type necrosis in a model of human DCIS using C2Am, an imaging agent that binds to the phosphatidylserine exposed by necrotic cells. METHODS: We used an established xenograft model of human DCIS that mimics the histopathological features of the disease. Planar near-infrared and optoacoustic imaging, using fluorescently labeled C2Am, were used to image non-invasively the presence and extent of lesion necrosis. RESULTS: C2Am showed specific and sensitive binding to necrotic areas in DCIS tissue, detectable both in vivo and ex vivo. The imaging signal generated in vivo using near-infrared (NIR) fluorescence imaging was up to 6-fold higher in DCIS lesions than in surrounding fat pad or skin tissue. There was a correlation between the C2Am NIR fluorescence (Pearson R = 0.783, P = 0.0125) and optoacoustic signals (R > 0.875, P < 0.022) in the DCIS lesions in vivo and the corresponding levels of cell death detected histologically. CONCLUSIONS: C2Am is a targeted multi-modal imaging agent that could complement current anatomical imaging methods for detecting DCIS. Imaging the presence and spatial extent of necrosis may give better prognostic information than that obtained by biopsy alone.

Non-hematologic diagnosis of systemic mastocytosis: Collaboration of radiology and pathology.

Systemic mastocytosis (SM) is a hematologic disease with a wide range of clinical courses ranging from an indolent condition with normal life expectancy to exceedingly aggressive disorder with a poor prognosis. The symptoms and signs of SM result from the release of mast cell mediators with heterogeneous functions, and/or organ damage from neoplastic mast cell infiltration, or both. Diagnostic criteria for SM are well-defined by the World Health Organization (WHO). However, the diagnosis of SM can be difficult when especially it is not in the differential diagnosis. Routinely used radiologic techniques (e.g., X-ray, ultrasound, CT scans can show findings such as lytic-, sclerotic- or mixed-bone lesions, splenomegaly, hepatomegaly, retroperitoneal or periportal mesenteric lymphadenopathy, and omental thickening). It is essential to emphasize that the constellation of these radiologic findings should strongly concern of SM, especially in patients who also have a skin rash, allergic reactions, gastrointestinal tract symptoms (lasting, intermittent nausea, diarrhea), paroxysmal tachycardias, unexplained weight loss, persistent bone pain, cytopenias, liver dysfunction, eosinophilia. These findings, even coincidentally noted, will likely lead to a tissue biopsy, which reveals diagnosis (as we discussed and illustrated some tissue biopsies here). Moreover, the role of MRI and new techniques such as [18-fluorodeoxyglucose positron emission computed tomography, fibroscan] in the diagnosis of SM have been discussed. Furthermore, we reviewed the use of radiologic methods to evaluate treatment response and prognostication of SM..

Perfusion weighted imaging using combined gradient/spin echo EPIK: Brain tumour applications in hybrid MR-PET.

Advanced perfusion-weighted imaging (PWI) methods that combine gradient echo (GE) and spin echo (SE) data are important tools for the study of brain tumours. In PWI, single-shot, EPI-based methods have been widely used due to their relatively high imaging speed. However, when used with increasing spatial resolution, single-shot EPI methods often show limitations in whole-brain coverage for multi-contrast applications. To overcome this limitation, this work employs a new version of EPI with keyhole (EPIK) to provide five echoes: two with GEs, two with mixed GESE and one with SE; the sequence is termed "GESE-EPIK." The performance of GESE-EPIK is evaluated against its nearest relative, EPI, in terms of the temporal signal-to-noise ratio (tSNR). Here, data from brain tumour patients were acquired using a hybrid 3T MR-BrainPET scanner. GESE-EPIK resulted in reduced susceptibility artefacts, shorter TEs for the five echoes and increased brain coverage when compared to EPI. Moreover, compared to EPI, EPIK achieved a comparable tSNR for the first and second echoes and significantly higher tSNR for other echoes. A new method to obtain multi-echo GE and SE data with shorter TEs and increased brain coverage is demonstrated. As proposed here, the workflow can be shortened and the integration of multimodal clinical MR-PET studies can be facilitated.

Screening of Potential Cardiac Involvement in Competitive Athletes Recovering From COVID-19: An Expert Consensus Statement.

As our understanding of the complications of coronavirus disease-2019 (COVID-19) evolve, subclinical cardiac pathology such as myocarditis, pericarditis, and right ventricular dysfunction in the absence of significant clinical symptoms represents a concern. The potential implications of these findings in athletes are significant given the concern that exercise, during the acute phase of viral myocarditis, may exacerbate myocardial injury and precipitate malignant ventricular arrhythmias. Such concerns have led to the development and publication of expert consensus documents aimed at providing guidance for the evaluation of athletes after contracting COVID-19 in order to permit safe return to play. Cardiac imaging is at the center of these evaluations. This review seeks to evaluate the current evidence regarding COVID-19-associated cardiovascular disease and how multimodality imaging may be useful in the screening and clinical evaluation of athletes with suspected cardiovascular complications of infection. Guidance is provided with diagnostic "red flags" that raise the suspicion of pathology. Specific emphasis is placed on the unique challenges posed in distinguishing athletic cardiac remodeling from subclinical cardiac disease. The strengths and limitations of different imaging modalities are discussed and an approach to return to play decision making for athletes post-COVID-19, as informed by multimodality imaging, is provided.

Rectal cancer: a methodological approach to matching PET/MRI to histopathology.

PURPOSE: To enable the evaluation of locoregional disease in the on-going RECTOPET (REctal Cancer Trial on PET/MRI/CT) study; a methodology to match mesorectal imaging findings to histopathology is presented, along with initial observations. METHODS: FDG-PET/MRI examinations were performed in twenty-four consecutively included patients with rectal adenocarcinoma. In nine patients, of whom five received neoadjuvant treatment, a postoperative MRI of the surgical specimen was performed. The pathological cut-out was performed according to clinical routine with the addition of photo documentation of each slice of the surgical specimen, meticulously marking the location, size, and type of pathology of each mesorectal finding. This allowed matching individual nodal structures from preoperative MRI, via the specimen MRI, to histopathology. RESULTS: Preoperative MRI identified 197 mesorectal nodal structures, of which 92 (47%) could be anatomically matched to histopathology. Of the matched nodal structures identified in both MRI and histopathology, 25% were found to be malignant. These malignant structures consisted of lymph nodes (43%), tumour deposits (48%), and extramural venous invasion (9%). One hundred eleven nodal structures (55%) could not be matched anatomically. Of these, 97 (87%) were benign lymph nodes, and 14 (13%) were malignant nodal structures. Five were malignant lymph nodes, and nine were tumour deposits, all of which had a short axis diameter < 5 mm. CONCLUSIONS: We designed a method able to anatomically match and study the characteristics of individual mesorectal nodal structures, enabling further research on the impact of each imaging modality. Initial observations suggest that small malignant nodal structures assessed as lymph nodes in MRI often comprise other forms of mesorectal tumour spread. TRIAL REGISTRATION: Clinical Trials Identifier: NCT03846882 .

Molecular imaging in immuno-oncology: current status and translational perspectives.

Introduction: Only 20-40% of patients respond to therapy with immune checkpoint inhibitors (ICIs). Therefore, the early identification of subjects that can benefit from such therapeutic regimen is mandatory. Areas covered: The immunobiological mechanisms of ICIs are briefly illustrated. Furthermore, the limitations of traditional radiological approaches are covered. Then, the pros and cons of molecular imaging through positron emission computed tomography (PET/CT) are reviewed, with a particular focus on 18f-fluorodeoxyglucose (18F-FDG) and PET-derived metabolic parameters. Lastly, translational perspective of radiopharmaceuticals others than 18F-FDG such as 89zirconium (89Zr) or fluorine-18 (18F) labeled monoclonal antibodies (e.g.89Zr-atezolizumab, 89Zr-nivolumab) binding to specific biomarkers are discussed. Expert opinion: Molecular imaging presents a prominent role for the management of oncological patients treated with ICIs. Preliminary clinical data indicate that PET/CT with 18F-FDG is useful for assessing the response to treatment and for the imaging of immune-related adverse effects. Nevertheless, the methodological approach (iPERCIST, PERCIMT, or others) to be used for an optimal diagnostic accuracy and patients' evaluation is still a debated issue. PET/CT with radioligands directed toward ICIs biomarkers, although is still in a translational phase, holds the promise of accurately predicting the response to treatment and revealing the acquired resistance to immunotherapy.

Diagnostic value of 18F-FDG PET/MRI for staging in patients with endometrial cancer.

BACKGROUND: Preoperative accurate assessment of endometrial cancer can assist in the planning of additional surgical options, and in predicting the prognosis. The aim of the present study was to evaluate the diagnostic potential of non-contrast PET/MRI with 18F-fluorodeoxyglucose (18F-FDG) for assessment in preoperative staging of endometrial cancer. METHODS: Thirty-six patients with biopsy-proven endometrial cancer underwent preoperative 18F-FDG PET/MRI, contrast-enhanced CT (ceCT) and pelvic dynamic contrast-enhanced MRI (ceMRI) for initial staging. The diagnostic performance of 18F-FDG PET/MRI and ceMRI for assessing the extent of the primary tumor (T stage), and 18F-FDG PET/MRI and ceCT for assessing nodal (N stage) and distant (M stage) metastasis, was evaluated by two experienced readers. Histopathological and follow-up imaging results were used as the gold standard. The McNemar test was employed for statistical analysis. RESULTS: Accuracy for T status was 77.8 and 75.0% for 18F-FDG PET/MRI and ceMRI, respectively. Patient-based accuracy for detecting regional nodal and distant metastasis was 91.3 and 81.8% for 18F-FDG PET/MRI, and 87.0 and 81.8% for ceCT. None of these parameters was statistically significant (p > 0.05). Lesion-based sensitivity, specificity and accuracy for detecting regional nodal metastasis were 100, 96.9 and 97.0% for 18F-FDG PET/MRI, and 14.3, 97.6 and 93.3% for ceCT; sensitivity was statistically significant (p < 0.05). CONCLUSIONS: Non-contrast 18F-FDG PET/MRI, which combines the individual advantages of PET and MRI, offers a high diagnostic value equivalent to that of ceMRI for assessment of the primary tumor, and equivalent to that of ceCT for the assessment of nodal and distant metastatic staging, in patients with endometrial cancer. These findings suggest that 18F-FDG PET/MRI might provide an alternative diagnostic strategy to conventional imaging modalities in the preoperative staging of endometrial cancer.

Clinical-stage Approaches for Imaging Chronic Inflammation and Fibrosis in Crohn's Disease.

The number of imaging-based indices developed for inflammatory bowel disease as research tools, objectively measuring ileocolonic and perianal activity and treatment response, has expanded in the past 2 decades. Created primarily to assess Crohn's disease (CD), there is increasing adoption of these indices into the clinical realm to guide patient care. This translation has been facilitated by validation in adult and pediatric populations, prompted by simplification of score calculations needed for practical application outside the research environment. The majority of these indices utilize magnetic resonance imaging (MRI), specifically MR enterography (MRE) and pelvic MRI, and more recently ultrasound. This review explores validated indices by modality, anatomic site and indication, including for documentation of the presence and extent of CD, disease progression, complications, and treatment response, highlighting those in clinical use or with the potential to be. As well, it details index imaging features used to quantify chronic inflammatory activity, severity, and to lesser extent fibrosis, in addition to their reference standards and any modifications. Validation in the pediatric population of indices primarily developed in adult cohorts such as the Magnetic Resonance Index of Activity (MaRIA), the Simplified Magnetic Resonance Index of Activity (MARIAs), and the MRE global score (MEGS), together with newly developed pediatric-specific indices, are discussed. Indices that may be predictive of disease course and investigational techniques with the potential to provide future imaging biomarkers, such as multiparametric MRI, are also briefly considered.

Risk of Prostate Cancer after a Negative Magnetic Resonance Imaging Guided Biopsy.

PURPOSE: Magnetic resonance imaging guided biopsy which reveals no cancer may impart reassurance beyond that offered by ultrasound guided biopsy. However, followup of men after a negative magnetic resonance imaging guided biopsy has been mostly by prostate specific antigen testing and reports of followup tissue confirmation are few. We investigated the incidence of clinically significant prostate cancer in such men who, because of persistent cancer suspicion, subsequently underwent a repeat magnetic resonance imaging guided biopsy. MATERIALS AND METHODS: Subjects were all men with a negative initial magnetic resonance imaging guided biopsy who underwent at least 1 further magnetic resonance imaging guided biopsy due to continued clinical suspicion of clinically significant prostate cancer (September 2009 to July 2019). Biopsies were magnetic resonance imaging-ultrasound fusion with targeted and systematic cores. Regions of interest from initial magnetic resonance imaging and any new regions of interest at followup magnetic resonance imaging guided biopsy were targeted. The primary end point was detection of clinically significant prostate cancer (Gleason Grade Group 2 or greater). RESULTS: Of 2,716 men 733 had a negative initial magnetic resonance imaging guided biopsy. Study subjects were 73/733 who underwent followup magnetic resonance imaging guided biopsy. Median (IQR) age and prostate specific antigen density were 64 years (59-67) and 0.12 ng/ml/cc (0.08-0.17), respectively. Baseline PI-RADS® scores were 3 or greater in 74%. At followup magnetic resonance imaging guided biopsy (median 2.4 years, IQR 1.3-3.6), 17/73 (23%) were diagnosed with clinically significant prostate cancer. When followup magnetic resonance imaging revealed a lesion (PI-RADS 3 or greater), clinically significant prostate cancer was found in 17/53 (32%). When followup magnetic resonance imaging was negative (PI-RADS less than 3), cancer was not found (0/20) (p <0.01). Overall 54% of men with PI-RADS 5 at followup magnetic resonance imaging guided biopsy were found to have clinically significant prostate cancer. CONCLUSIONS: Men with negative magnetic resonance imaging following an initial negative magnetic resonance imaging guided biopsy are unlikely to harbor clinically significant prostate cancer and may avoid repeat biopsy. However, when lesions are seen on followup magnetic resonance imaging, repeat magnetic resonance imaging guided biopsy is warranted.

Anatomic and Functional Imaging of Neuroendocrine Tumors.

OPINION STATEMENT: Neuroendocrine tumors (NETs) can occur in a wide variety of organs and display a spectrum of pathologic behavior. Accurate and effective imaging is paramount to the diagnosis, staging, therapy, and surveillance of patients with NET. There have been continuous advancements in the imaging of NET which includes anatomic and functional techniques.

Improving MR sequence of 18F-FDG PET/MR for diagnosing and staging gastric Cancer: a comparison study to 18F-FDG PET/CT.

PURPOSE: Evaluate the feasibility of fluorine-18 (18F) fluorodeoxyglucose (FDG) positron emission tomography (PET) and magnetic resonance (MR) imaging in patients with gastric cancer by optimizing the scan protocol and to compare the image quality to 18F FDG PET and computed tomography (CT). METHODS: The PET/CT and PET/MR imaging were sequentially performed in 30 patients with gastric cancer diagnosed by gastroscope using a single-injection-with-dual-imaging protocol. After intravenous injection of 18F-FDG (mean, 249 MBq), PET/CT imaging including low-dose CT was performed (mean uptake time, 47 ± 6 min), and PET/MR imaging including a T1-weighted Dixon sequence for attenuation correction and two different T2-weighted sequences was subsequently acquired (88 ± 15 min after 18F-FDG injection). Four series of images (CT from PET/CT, T1W, T2W Half-Fourier acquisition single-shot turbo spin-echo [T2W-HASTE] and T2W-BLADE from PET/MR) were visually evaluated using a 3-4 points scale for: (1) image artifacts, (2) lesion conspicuity and (3) image fusion quality. The characteristics of the primary lesions were assessed and compared between the PET/CT and PET/MR acquisitions. RESULTS: The image quality and lesion conspicuity of the T2W-HASTE images were significantly improved compared to that of the T2W-BLADE images. A significantly higher number of artifacts were seen in the T2W-HASTE images compared with the T1W and CT images (p < 0. 05). No differences in the accuracy of image fusion between PET/MR and PET/CT (p > 0. 05); however, significant difference was seen in the lesion conspicuity measurements (p < 0.05) with T2W-HASTE being superior. For information about the primary lesion characteristics, the T2W-HASTE images provided the most successful identifications compared with those of the T1W and PET/CT (13vs7vs5) images. CONCLUSIONS: PET/MR with the T2W-HASTE was better at revealing the details of local stomach lesions compared with PET/CT imaging. Combining the PET/MR with the T2W-HASTE technique is a promising imaging method for diagnosing and staging gastric cancer.

Multimodal imaging in radiotherapy: Focus on adaptive therapy and quality control.

Improved computer resources in radiation oncology department have greatly facilitated the integration of multimodal imaging into the workflow of radiation therapy. Nowadays, physicians have highly informative imaging modalities of the anatomical region to be treated. These images contribute to the targeting accuracy with the current treatment device, impacting both segmentation or patient's positioning. Additionally, in a constant effort to deliver personalized care, many teams seek to confirm the benefits of adaptive radiotherapy. The published works highlight the importance of registration algorithms, particularly those of elastic or deformable registration necessary to take into account the anatomical evolutions of the patients during the course of their therapy. These algorithms, often considered as "black boxes", tend to be better controlled and understood by physicists and physicians thanks to the generalization of evaluation and validation methods. Given the still significant development of medical imaging techniques, it is foreseeable that multimodal registration needs require more efficient algorithms well integrated within the flow of data.

Multi-modal radiomics model to predict treatment response to neoadjuvant chemotherapy for locally advanced rectal cancer.

BACKGROUND: Neoadjuvant chemotherapy is currently recommended as preoperative treatment for locally advanced rectal cancer (LARC); however, evaluation of treatment response to neoadjuvant chemotherapy is still challenging. AIM: To create a multi-modal radiomics model to assess therapeutic response after neoadjuvant chemotherapy for LARC. METHODS: This retrospective study consecutively included 118 patients with LARC who underwent both computed tomography (CT) and magnetic resonance imaging (MRI) before neoadjuvant chemotherapy between October 2016 and June 2019. Histopathological findings were used as the reference standard for pathological response. Patients were randomly divided into a training set (n = 70) and a validation set (n = 48). The performance of different models based on CT and MRI, including apparent diffusion coefficient (ADC), dynamic contrast enhanced T1 images (DCE-T1), high resolution T2-weighted imaging (HR-T2WI), and imaging features, was assessed by using the receiver operating characteristic curve analysis. This was demonstrated as area under the curve (AUC) and accuracy (ACC). Calibration plots with Hosmer-Lemeshow tests were used to investigate the agreement and performance characteristics of the nomogram. RESULTS: Eighty out of 118 patients (68%) achieved a pathological response. For an individual radiomics model, HR-T2WI performed better (AUC = 0.859, ACC = 0.896) than CT (AUC = 0.766, ACC = 0.792), DCE-T1 (AUC = 0.812, ACC = 0.854), and ADC (AUC = 0.828, ACC = 0.833) in the validation set. The imaging performance for extramural venous invasion detection was relatively low in both the training (AUC = 0.73, ACC = 0.714) and validation (AUC = 0.578, ACC = 0.583) sets. The multi-modal radiomics model reached an AUC of 0.925 and ACC of 0.886 in the training set, and an AUC of 0.93 and ACC of 0.875 in the validation set. For the clinical radiomics nomogram, good agreement was found between the nomogram prediction and actual observation. CONCLUSION: A multi-modal nomogram using traditional imaging features and radiomics of preoperative CT and MRI adds accuracy to the prediction of treatment outcome, and thus contributes to the personalized selection of neoadjuvant chemotherapy for LARC.

Fiducial markers visibility and artefacts in prostate cancer radiotherapy multi-modality imaging.

BACKGROUND: In this study, a novel pelvic phantom was developed and used to assess the visibility and presence of artefacts from different types of commercial fiducial markers (FMs) on multi-modality imaging relevant to prostate cancer. METHODS AND MATERIALS: The phantom was designed with 3D printed hollow cubes in the centre. These cubes were filled with gel to mimic the prostate gland and two parallel PVC rods were used to mimic bones in the pelvic region. Each cube was filled with gelatine and three unique FMs were positioned with a clinically-relevant spatial distribution. The FMs investigated were; Gold Marker (GM) CIVCO, GM RiverPoint, GM Gold Anchor (GA) line and ball shape, and polymer marker (PM) from CIVCO. The phantom was scanned using several imaging modalities typically used to image prostate cancer patients; MRI, CT, CBCT, planar kV-pair, ExacTrac, 6MV, 2.5MV and integrated EPID imaging. The visibility of the markers and any observed artefacts in the phantom were compared to in-vivo scans of prostate cancer patients with FMs. RESULTS: All GMs were visible in volumetric scans, however, they also had the most visible artefacts on CT and CBCT scans, with the magnitude of artefacts increasing with FM size. PM FMs had the least visible artefacts in volumetric scans but they were not visible on portal images and had poor visibility on lateral kV images. The smallest diameter GMs (GA) were the most difficult GMs to identify on lateral kV images. CONCLUSION: The choice between different FMs is also dependent on the adopted IGRT strategy. PM was found to be superior to investigated gold markers in the most commonly used modalities in the management of prostate cancer; CT, CBCT and MRI imaging.

The added diagnostic value of complementary gadoxetic acid-enhanced MRI to 18F-DOPA-PET/CT for liver staging in medullary thyroid carcinoma.

BACKGROUND: A high proportion of patients with advanced stages of medullary thyroid carcinoma (MTC) present with liver metastasis metastases. The aim of our study was to investigate the added diagnostic value of complementary gadoxetic acid-enhanced MRI to 18F-DOPA-PET/CT for liver staging in MTC. METHODS: Thirty-six patients (14 female, median age 55 years) with histologically confirmed MTC undergoing gadoxetic acid-enhanced liver MRI within 1 month of matching contrast-enhanced 18F-DOPA-PET/CT between 2010 and 2016 were selected for this IRB-approved retrospective study. 18F-DOPA-PET/CT and multiparametric MRI data sets were read consecutively and liver lesions were categorised on a 5-point Likert scale (1-definitely benign; 2-probably benign; 3-intermediate risk for metastasis; 4-probably metastasis; 5-definitely metastasis). It was noted if gadoxetic acid-enhanced MRI detected additional, 18F-DOPA-PET/CT-occult metastases (category 5) or if gadoxetic acid-enhanced MRI allowed for a definite classification (categories 1 and 5) of lesions for which 18F-DOPA-PET/CT remained inconclusive (categories 2-4). Follow-up PET/CT and MRI examinations were used as a reference standard. RESULTS: A total of 207 liver lesions (18F-DOPA-PET/CT 149, MRI 207; 152 metastases, 37 benign cysts, 18 hemangiomas) were analysed. Fifty-eight additional lesions were detected by MRI, of which 54 were metastases (median diameter 0.5 cm [interquartile range 0.4-0.7 cm]) occult on 18F-DOPA-PET/CT. MRI allowed for a definite lesion classification (categories 1 and 5) in 92% (190/207) whereas 18F-DOPA-PET/CT allowed for a definite lesion classification in 76% (113/149). MRI lead to a change in lesion categorisation in 14% (21/149). CONCLUSION: Gadoxetic acid-enhanced MRI allows for a more precise liver staging in MTC patients compared to 18F-DOPA-PET/CT alone, particularly for 18F-DOPA-negative metastases and lesions < 1 cm.