ESR Essentials: response assessment criteria in oncologic imaging-practice recommendations by the European Society of Oncologic Imaging.

Assessing the response to oncological treatments is paramount for determining the prognosis and defining the best treatment for each patient. Several biomarkers, including imaging, can be used, but standardization is fundamental for consistency and reliability. Tumor response evaluation criteria have been defined by international groups for application in pharmaceutical clinical trials evaluating new drugs or therapeutic strategies. RECIST 1.1 criteria are exclusively based on unidimensional lesion measurements; changes in tumor size are used as surrogate imaging biomarkers to correlate with patient outcomes. However, increased tumor size does not always reflect tumor progression. The introduction of immunotherapy has led to the development of new criteria (iRECIST, Level of Evidence (LoE) Ib) that consider the possibility that an increase in disease burden is secondary to the immune response instead of progression, with the new concept of Unconfirmed Progressive Disease (a first progression event which must be confirmed on follow-up). Specific criteria were devised for HCC (mRECIST, LoE IV), which measure only enhancing HCC portions to account for changes after local therapy. For GIST treated with imatinib, criteria were developed to account for the possible increase in size reflecting a response rather than a progression by assessing both tumor size and density on CT (Choi, LoE II). This article provides concise and relevant practice recommendations aimed at general radiologists to help choose and apply the most appropriate criteria for assessing response to treatment in different oncologic scenarios. Though these criteria were developed for clinical trials, they may be applied in clinical practice as a guide for day-to-day interpretation. KEY POINTS: Response evaluation criteria, designed for use in clinical trials, might serve as a surrogate biomarker for overall survival. RECIST 1.1 defines measurable and non-measurable disease among which target lesions and non-target lesions are selected at baseline as reference for follow-ups. Some therapies and/or cancers require the use of different criteria, such as iRECIST, mRECIST, and Choi criteria.

Multivariable prognostic modelling to improve prediction of colorectal cancer recurrence: the PROSPeCT trial.

OBJECTIVE: Improving prognostication to direct personalised therapy remains an unmet need. This study prospectively investigated promising CT, genetic, and immunohistochemical markers to improve the prediction of colorectal cancer recurrence. MATERIAL AND METHODS: This multicentre trial (ISRCTN 95037515) recruited patients with primary colorectal cancer undergoing CT staging from 13 hospitals. Follow-up identified cancer recurrence and death. A baseline model for cancer recurrence at 3 years was developed from pre-specified clinicopathological variables (age, sex, tumour-node stage, tumour size, location, extramural venous invasion, and treatment). Then, CT perfusion (blood flow, blood volume, transit time and permeability), genetic (RAS, RAF, and DNA mismatch repair), and immunohistochemical markers of angiogenesis and hypoxia (CD105, vascular endothelial growth factor, glucose transporter protein, and hypoxia-inducible factor) were added to assess whether prediction improved over tumour-node staging alone as the main outcome measure. RESULTS: Three hundred twenty-six of 448 participants formed the final cohort (226 male; mean 66 ± 10 years. 227 (70%) had ≥ T3 stage cancers; 151 (46%) were node-positive; 81 (25%) developed subsequent recurrence. The sensitivity and specificity of staging alone for recurrence were 0.56 [95% CI: 0.44, 0.67] and 0.58 [0.51, 0.64], respectively. The baseline clinicopathologic model improved specificity (0.74 [0.68, 0.79], with equivalent sensitivity of 0.57 [0.45, 0.68] for high vs medium/low-risk participants. The addition of prespecified CT perfusion, genetic, and immunohistochemical markers did not improve prediction over and above the clinicopathologic model (sensitivity, 0.58-0.68; specificity, 0.75-0.76). CONCLUSION: A multivariable clinicopathological model outperformed staging in identifying patients at high risk of recurrence. Promising CT, genetic, and immunohistochemical markers investigated did not further improve prognostication in rigorous prospective evaluation. CLINICAL RELEVANCE STATEMENT: A prognostic model based on clinicopathological variables including age, sex, tumour-node stage, size, location, and extramural venous invasion better identifies colorectal cancer patients at high risk of recurrence for neoadjuvant/adjuvant therapy than stage alone. KEY POINTS: Identification of colorectal cancer patients at high risk of recurrence is an unmet need for treatment personalisation. This model for recurrence, incorporating many patient variables, had higher specificity than staging alone. Continued optimisation of risk stratification schema will help individualise treatment plans and follow-up schedules.

Attitudes and perceptions of radiologists towards online (virtual) oncologic multidisciplinary team meetings during the COVID-19 pandemic-a survey of the European Society of Oncologic Imaging (ESOI).

OBJECTIVES: To explore radiologists' opinions regarding the shift from in-person oncologic multidisciplinary team meetings (MDTMs) to online MDTMs. To assess the perceived impact of online MDTMs, and to evaluate clinical and technical aspects of online meetings. METHODS: An online questionnaire including 24 questions was e-mailed to all European Society of Oncologic Imaging (ESOI) members. Questions targeted the structure and efficacy of online MDTMs, including benefits and limitations. RESULTS: A total of 204 radiologists responded to the survey. Responses were evaluated using descriptive statistical analysis. The majority (157/204; 77%) reported a shift to online MDTMs at the start of the pandemic. For the most part, this transition had a positive effect on maintaining and improving attendance. The majority of participants reported that online MDTMs provide the same clinical standard as in-person meetings, and that interdisciplinary discussion and review of imaging data were not hindered. Seventy three of 204 (35.8%) participants favour reverting to in-person MDTs, once safe to do so, while 7/204 (3.4%) prefer a continuation of online MDTMs. The majority (124/204, 60.8%) prefer a combination of physical and online MDTMs. CONCLUSIONS: Online MDTMs are a viable alternative to in-person meetings enabling continued timely high-quality provision of care with maintained coordination between specialties. They were accepted by the majority of surveyed radiologists who also favoured their continuation after the pandemic, preferably in combination with in-person meetings. An awareness of communication issues particular to online meetings is important. Training, improved software, and availability of support are essential to overcome technical and IT difficulties reported by participants. KEY POINTS: • Majority of surveyed radiologists reported shift from in-person to online oncologic MDT meetings during the COVID-19 pandemic. • The shift to online MDTMs was feasible and generally accepted by the radiologists surveyed with the majority reporting that online MDTMs provide the same clinical standard as in-person meetings. • Most would favour the return to in-person MDTMs but would also accept the continued use of online MDTMs following the end of the current pandemic.

Involvement of radiologists in oncologic multidisciplinary team meetings: an international survey by the European Society of Oncologic Imaging.

OBJECTIVES: Multidisciplinary tumour boards (MTBs) play an increasingly important role in managing cancer patients from diagnosis to treatment. However, many problems arise around the organisation of MTBs, both in terms of organisation-administration and time management. In this context, the European Society of Oncologic Imaging (ESOI) conducted a survey among its members, aimed at assessing the quality and amount of involvement of radiologists in MTBs, their role in it and related issues. METHODS: All members were invited to fill in a questionnaire consisting of 15 questions with both open and multiple-choice answers. Simple descriptive analyses and graphs were performed. RESULTS: A total of 292 ESOI members in full standing for the year 2018 joined the survey. Most respondents (89%) declared to attend MT-Bs, but only 114 respondents (43.9%) review over 70% of exams prior to MTB meetings, mainly due to lack of time due to a busy schedule for imaging and reporting (46.6%). Perceived benefits (i.e. surgical and histological feedback (86.9%), improved knowledge of cancer treatment (82.7%) and better interaction between radiologists and referring clinicians for discussing rare cases (56.9%)) and issues (i.e. attending MTB meetings during regular working hours (71.9%) and lack of accreditation with continuing medical education (CME) (85%)) are reported. CONCLUSIONS: Despite the value and benefits of radiologists' participation in MTBs, issues like improper preparation due to a busy schedule and no counterpart in CME accreditation require efforts to improve the role of radiologists for a better patient care. KEY POINTS: • Most radiologists attend multidisciplinary tumour boards, but less than half of them review images in advance, mostly due to time constraints. • Feedback about radiological diagnoses, improved knowledge of cancer treatment and interaction with referring clinicians are perceived as major benefits. • Concerns were expressed about scheduling multidisciplinary tumour boards during regular working hours and lack of accreditation with continuing medical education.

The impact of MRI sequence on tumour staging and gross tumour volume delineation in squamous cell carcinoma of the anal canal.

OBJECTIVES: To compare maximum tumour diameter (MTD) and gross tumour volume (GTV) measurements between T2-weighted (T2-w) and diffusion-weighted (DWI) MRI in squamous cell carcinoma of the anal canal (SCCA) and assess sequence impact on tumour (T) staging. Second, to evaluate interobserver agreement and reader delineation confidence. METHODS: The staging MRI scans of 45 SCCA patients (25 females) were assessed retrospectively by two independent radiologists (0 and 5 years' experience of anal cancer MRI). MTD and GTV were delineated on both T2-w and high-b-value DWI images and compared between sequences; T staging was derived from MTD. Interobserver agreement was assessed and delineation confidence scored (1 to 5) by each observer. RESULTS: GTV and MTD were significantly and systematically lower on DWI versus T2-w sequences by 14.80%/9.98% (MTD) and 29.70%/12.25% (GTV) for each reader, respectively, causing T staging discordances in approximately a quarter of cases. Bland-Altman limits of agreement were narrower and intraclass correlation coefficients higher for DWI. Delineation confidence was greater on DWI: 40/42 cases were scored confidently (4 or 5) by each reader, respectively, versus 31/36 cases based on T2-w images. CONCLUSIONS: Sequence selection affects SCCA measurements and T stage. DWI yields higher interobserver agreement and greater tumour delineation confidence. KEY POINTS: • MTD and GTV measurements are significantly lower on DWI than on T 2 -w MRI. • Such differences cause T staging discordances in up to a quarter of cases. • DWI results in higher agreement between inexperienced and experienced observers. • DWI offers greater tumour delineation confidence to inexperienced readers.

Magnetic resonance imaging for clinical management of rectal cancer: Updated recommendations from the 2016 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) consensus meeting.

OBJECTIVES: To update the 2012 ESGAR consensus guidelines on the acquisition, interpretation and reporting of magnetic resonance imaging (MRI) for clinical staging and restaging of rectal cancer. METHODS: Fourteen abdominal imaging experts from the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) participated in a consensus meeting, organised according to an adaptation of the RAND-UCLA Appropriateness Method. Two independent (non-voting) Chairs facilitated the meeting. 246 items were scored (comprising 229 items from the previous 2012 consensus and 17 additional items) and classified as 'appropriate' or 'inappropriate' (defined by ≥ 80 % consensus) or uncertain (defined by < 80 % consensus). RESULTS: Consensus was reached for 226 (92 %) of items. From these recommendations regarding hardware, patient preparation, imaging sequences and acquisition, criteria for MR imaging evaluation and reporting structure were constructed. The main additions to the 2012 consensus include recommendations regarding use of diffusion-weighted imaging, criteria for nodal staging and a recommended structured report template. CONCLUSIONS: These updated expert consensus recommendations should be used as clinical guidelines for primary staging and restaging of rectal cancer using MRI. KEY POINTS: • These guidelines present recommendations for staging and reporting of rectal cancer. • The guidelines were constructed through consensus amongst 14 pelvic imaging experts. • Consensus was reached by the experts for 92 % of the 246 items discussed. • Practical guidelines for nodal staging are proposed. • A structured reporting template is presented.

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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, 70.0 years]) were analyzed to extract (a) global first-order statistical histogram and model-based fractal features reflecting the whole-tumor voxel intensity histogram distribution and repeating patterns, respectively, without spatial information and (b) local-regional second-order and high-order statistical texture features reflecting the intensity and spatial interrelationships between adjacent in-plane or multiplanar voxels or regions, respectively. Repeatability was assessed for 46 texture features, and mean difference, 95% limits of agreement, within-subject coefficient of variation (wCV), and repeatability coefficient (r) were recorded. Results Repeatability was better for global parameters than for most local-regional parameters. In particular, histogram mean, median, and entropy, fractal dimension mean and standard deviation, and second-order entropy, homogeneity, difference entropy, and inverse difference moment demonstrated good repeatability, with narrow limits of agreement and wCVs of 10% or lower. Repeatability was poorest for the following high-order gray-level run-length (GLRL) gray-level zone size matrix (GLZSM) and neighborhood gray-tone difference matrix (NGTDM) parameters: GLRL intensity variability, GLZSM short-zone emphasis, GLZSM intensity nonuniformity, GLZSM intensity variability, GLZSM size zone variability, and NGTDM complexity, demonstrating wider agreement limits and wCVs of 50% or greater. Conclusion MR imaging repeatability is better for global texture parameters than for local-regional texture parameters, indicating that global texture parameters should be sufficiently robust for clinical practice. Online supplemental material is available for this article.

Split-bolus spectral multidetector CT of the pancreas: assessment of radiation dose and tumor conspicuity.

PURPOSE: To assess tumor conspicuity and radiation dose with a new multidetector computed tomography (CT) protocol for pancreatic imaging that combines spectral CT and split-bolus injection. MATERIALS AND METHODS: This study was approved by the institutional review board and compliant with HIPAA. The requirement for informed consent was waived. One hundred sixty-three consecutive patients referred for possible pancreatic mass underwent CT with either a standard or split-bolus spectral CT protocol depending on scanner availability. Split-bolus spectral CT (CT unit with spectral imaging) combines pancreatic and portal venous phases in a single scan: 70 seconds before CT, 100 mL of contrast material is injected for the portal venous phase followed approximately 35 seconds later by injection of 40 mL of contrast material to boost the pancreatic phase. Bolus tracking after the second bolus initiates scanning 15 seconds after aorta enhancement reaches 280 HU. Images were reconstructed at 60 and 77 keV. The standard protocol (64-detector row unit) included unenhanced and pancreatic and portal venous phase imaging, with a single contrast material injection timed with bolus tracking 15 seconds after aortic enhancement of 300 HU for the pancreatic phase and 32 seconds later for the portal venous phase. Tumor conspicuity (difference in attenuation between tumor and pancreatic parenchyma) and contrast-to-noise ratio (CNR) were determined. Attenuation of aorta, main portal vein, and liver were measured. Patient size and per-examination radiation dose were recorded. The heteroscedastic t test, Fisher exact test, and Mann-Whitney test were used for statistical analysis. RESULTS: There were no significant differences in age, weight, and body mass index between patients in the standard CT (46 of 80 patients had lesions) and split-bolus spectral CT (39 of 83 patients had lesions) groups; however, there were significantly more women in the split-bolus group (P = .02). Tumor conspicuity and CNR were higher with the 60-keV split-bolus protocol (89.1 HU ± 56.6 and 8.8 ± 6.2, respectively) than with the pancreatic or portal venous phase of the standard protocol (43.5 HU ± 28.4 and 4.5 ± 3.0, and 51.5 HU ± 30.3 and 5.6 ± 4.0, respectively; P < .01 for all comparisons). Dose-length product was 1112 mGy · cm ± 437 with the standard protocol and 633 mGy · cm ± 105 with the split-bolus protocol (P < .001). CONCLUSION: Split-bolus spectral multidetector CT resulted in vascular, liver, and pancreatic attenuation and tumor conspicuity equal to or greater than that with multiphase CT, with a 43% reduction in radiation dose.

Magnetic resonance imaging for the clinical management of rectal cancer patients: recommendations from the 2012 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) consensus meeting.

OBJECTIVES: To develop guidelines describing a standardised approach regarding the acquisition, interpretation and reporting of magnetic resonance imaging (MRI) for clinical staging and restaging of rectal cancer. METHODS: A consensus meeting of 14 abdominal imaging experts from the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) was conducted following the RAND-UCLA Appropriateness Method. Two independent (non-voting) chairs facilitated the meeting. Two hundred and thirty-six items were scored by participants for appropriateness and classified subsequently as appropriate or inappropriate (defined by ≥ 80 % consensus) or uncertain (defined by < 80 % consensus). Items not reaching 80 % consensus were noted. RESULTS: Consensus was reached for 88 % of items: recommendations regarding hardware, patient preparation, imaging sequences, angulation, criteria for MRI assessment and MRI reporting were constructed from these. CONCLUSIONS: These expert consensus recommendations can be used as clinical guidelines for primary staging and restaging of rectal cancer using MRI. KEY POINTS: • These guidelines recommend standardised imaging for staging and restaging of rectal cancer. • The guidelines were constructed through consensus amongst 14 abdominal imaging experts. • Consensus was reached by in 88 % of 236 items discussed.

Intraductal Papillary Mucinous Neoplasm of the Pancreas: A Challenging Diagnosis.

Intraductal papillary mucinous neoplasm of the pancreas (IPMN) was classified as a distinct entity from mucinous cystic neoplasm by the WHO in 1995. It represents a mucin-producing tumor that originates from the ductal epithelium and can evolve from slight dysplasia to invasive carcinoma. In addition, different aspects of tumor progression may be seen in the same lesion. Three types are recognized, the branch duct variant, the main duct variant, which shows a much higher prevalence for malignancy, and the mixed-type variant, which combines branch and main duct characteristics. Advances in cross-sectional imaging have led to an increased rate of IPMN detection. The main imaging characteristic of IPMN is the dilatation of the pancreatic duct without the presence of an obstructing lesion. The diagnosis of a branch duct IPMN is based on the proof of its communication with the main pancreatic duct on MRI-MRCP examination. Early identification by imaging of the so-called worrisome features or predictors for malignancy is an important and challenging task. In this review, we will present recent imaging advances in the diagnosis and characterization of different types of IPMNs, as well as imaging tools available for early recognition of worrisome features for malignancy. A critical appraisal of current IPMN management guidelines from both a radiologist's and surgeon's perspective will be made. Special mention is made of complications that might arise during the course of IPMNs as well as concomitant pancreatic neoplasms including pancreatic adenocarcinoma and pancreatic endocrine neoplasms. Finally, recent research on prognostic and predictive biomarkers including radiomics will be discussed.

The Spectrum of Solitary Benign Splenic Lesions-Imaging Clues for a Noninvasive Diagnosis.

Cross-sectional imaging of the upper abdomen, especially if intravenous contrast has been administered, will most likely reveal any acute or chronic disease harbored in the spleen. Unless imaging is performed with the specific purpose of evaluating the spleen or characterizing a known splenic lesion, incidentally discovered splenic lesions pose a small challenge. Solitary benign splenic lesions include cysts, hemangiomas, sclerosing angiomatous nodular transformation (SANT), hamartomas, and abscesses, among others. Sarcoidosis and tuberculosis, although predominantly diffuse micronodular disease processes, may also present as a solitary splenic mass lesion. In addition, infarction and rupture, both traumatic and spontaneous, may take place in the spleen. This review aims to describe the imaging features of the most common benign focal splenic lesions, with emphasis on the imaging findings as these are encountered on routine cross-sectional imaging from a multicenter pool of cases that, coupled with clinical information, can allow a definite diagnosis.

An Automated Prognostic Model for Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) constitutes a leading cause of cancer-related mortality despite advances in detection and treatment methods. While computed tomography (CT) serves as the current gold standard for initial evaluation of PDAC, its prognostic value remains limited, as it relies on diagnostic stage parameters encompassing tumor size, lymph node involvement, and metastasis. Radiomics have recently shown promise in predicting postoperative survival of PDAC patients; however, they rely on manual pancreas and tumor delineation by clinicians. In this study, we collected a dataset of pre-operative CT scans from a cohort of 40 PDAC patients to evaluate a fully automated pipeline for survival prediction. Employing nnU-Net trained on an external dataset, we generated automated pancreas and tumor segmentations. Subsequently, we extracted 854 radiomic features from each segmentation, which we narrowed down to 29 via feature selection. We then combined these features with the Tumor, Node, Metastasis (TNM) system staging parameters, as well as the patient's age. We trained a random survival forest model to perform an overall survival prediction over time, as well as a random forest classifier for the binary classification of two-year survival, using repeated cross-validation for evaluation. Our results exhibited promise, with a mean C-index of 0.731 for survival modeling and a mean accuracy of 0.76 in two-year survival prediction, providing evidence of the feasibility and potential efficacy of a fully automated pipeline for PDAC prognostication. By eliminating the labor-intensive manual segmentation process, our streamlined pipeline demonstrates an efficient and accurate prognostication process, laying the foundation for future research endeavors.

Spectral CT with metal artifacts reduction software for improvement of tumor visibility in the vicinity of gold fiducial markers.

PURPOSE: To evaluate spectral computed tomography (CT) with metal artifacts reduction software (MARS) for reduction of metal artifacts associated with gold fiducial seeds. MATERIALS AND METHODS: Thirteen consecutive patients with 37 fiducial seeds implanted for radiation therapy of abdominal lesions were included in this HIPAA-compliant, institutional review board-approved prospective study. Six patients were women (46%) and seven were men (54%). The mean age was 61.1 years (median, 58 years; range, 29-78 years). Spectral imaging was used for arterial phase CT. Images were reconstructed with and without MARS in axial, coronal, and sagittal planes. Two radiologists independently reviewed reconstructions and selected the best image, graded the visibility of the tumor, and assessed the amount of artifacts in all planes. A linear-weighted κ statistic and Wilcoxon signed-rank test were used to assess interobserver variability. Histogram analysis with the Kolmogorov-Smirnov test was used for objective evaluation of artifacts reduction. RESULTS: Fiducial seeds were placed in pancreas (n = 5), liver (n = 7), periportal lymph nodes (n = 1), and gallbladder bed (n = 1). MARS-reconstructed images received a better grade than those with standard reconstruction in 60% and 65% of patients by the first and second radiologist, respectively. Tumor visibility was graded higher with standard versus MARS reconstruction (grade, 3.7 ± 1.0 vs 2.8 ± 1.1; P = .001). Reduction of blooming was noted on MARS-reconstructed images (P = .01). Amount of artifacts, for both any and near field, was significantly smaller on sagittal and coronal MARS-reconstructed images than on standard reconstructions (P < .001 for all comparisons). Far-field artifacts were more prominent on axial MARS-reconstructed images than on standard reconstructions (P < .01). Linear-weighted κ statistic showed moderate to perfect agreement between radiologists. CT number distribution was narrower with MARS than with standard reconstruction in 35 of 37 patients (P < .001). CONCLUSION: Spectral CT with use of MARS improved tumor visibility in the vicinity of gold fiducial seeds.

Safety profile and technical success of imaging-guided percutaneous fiducial seed placement with and without core biopsy in the abdomen and pelvis.

OBJECTIVE: The purpose of this study is to determine whether complications associated with combining biopsy and percutaneous fiducial seed placement in the abdomen and pelvis exceeds that of either procedure alone or prohibits completion of the combined procedure. MATERIALS AND METHODS: A retrospective review was performed of 188 consecutive patients who underwent CT- or ultrasound-guided placement of fiducial seeds in the abdomen or pelvis, either alone (group 1, n = 117) or with concomitant biopsy (group 2, n = 71), from October 2005 through April 2010. Complications classified according to the Society of Interventional Radiology guidelines were compared between both groups using the Z test for proportions, as were the number of seeds per patient and seed migration and technical success rates. RESULTS: One hundred eighty-eight patients underwent percutaneous placement of 533 fiducial seeds in the abdomen and pelvis. Eight patients (4.3%) had complications. Five were minor (four small hematomas and one pneumothorax) and three were major (two cases of bleeding and one of sepsis). There was no significant difference between groups with respect to minor complication rates, number of seeds placed per patient (p = 0.85), or technical success (p = 0.33). Significantly more major complications (p = 0.04) occurred in group 2, but the rate was similar to that for percutaneous biopsy alone as reported in the literature. Group 2 also had more seed migration (p = 0.02). CONCLUSION: Biopsy and fiducial seed placement in the abdomen and pelvis can be performed in the same session rather than separately, with a high rate of technical success and without an increased risk of complications when compared with either procedure alone.

Comparison between 1.5-T and 3.0-T MRI for the diagnosis of placenta accreta spectrum disorders.

PURPOSE: Accurate antenatal diagnosis of placenta accreta spectrum (PAS) is important for optimal management. The purpose of this study was to compare the respective capabilities of 1.5-T and 3.0-T MRI in the diagnosis of PAS. MATERIALS AND METHODS: Between March 2016-March 2021, 190 pregnant women at high risk for PAS underwent dedicated prenatal MRI with either 1.5-T or 3.0-T units at a tertiary imaging center. Cesarian section and MRI were performed less than 6 weeks from each other. Prospectively collected data were evaluated by two experienced genitourinary radiologists for presence and extent of PAS. A comparative study was designed to investigate differences in predictive ability between 1.5-T and 3.0-T MRI groups. Sensitivity, specificity, accuracy, negative and positive prognostic values relative to intraoperative/histological findings, were computed for both groups and were compared with chi-square (χ 2) test. Interobserver agreement was estimated using Kappa test. RESULTS: One hundred-eighty-two gravid women were included in the study; of these, 91/182 (50%) women were evaluated with 1.5-T (mean age, 35 ± 5.1 [SD] years; mean gestational age: 32.5 weeks) and 91/182 (50%) with 3.0-T MRI (mean age, 34.9 ± 4.9 [SD] years; mean gestational age, 32.1 weeks). 1.5-T MRI yielded 95.7% sensitivity (95% CI: 87.8-99.1) and 81.8% specificity (95% CI: 59.8) and 3.0-T MRI 93.8% sensitivity (95% CI: 86.0-97.9) and 83.3% specificity (95% CI: 48.2-97.7) for PAS identification, with no differences between the two groups (P = 0.725 and P >0.999, respectively). MRI showed excellent predictive ability for detecting extrauterine placental spread with 100% sensitivity (95% CI: 89.4-100.0), 96.7% specificity (95% CI: 88.1-99.6) for 1.5-T and 97% sensitivity (95% CI: 84.2-99.9), 96.7% specificity (95% CI: 88.1-99.6) for 3.0-T without differences between the two groups (P > 0.999). Interobserver agreement was excellent for both groups. The most frequently detected MRI signs of PAS for both 1.5-T and 3.0-T groups were placental heterogeneity (n = 85, 93.5% vs. n = 90, 98.9%; P = 0.413), and intraplacental fetal vessels (n = 64, 70.3% vs. n = 65, 71.4%; P = 0.870). CONCLUSION: This study suggests that 3.0-T MRI and 1.5-T MRI are equivalent for the diagnosis of PAS.

Imaging standardisation in metastatic colorectal cancer: A joint EORTC-ESOI-ESGAR expert consensus recommendation.

BACKGROUND: Treatment monitoring in metastatic colorectal cancer (mCRC) relies on imaging to evaluate the tumour burden. Response Evaluation Criteria in Solid Tumors provide a framework on reporting and interpretation of imaging findings yet offer no guidance on a standardised imaging protocol tailored to patients with mCRC. Imaging protocol heterogeneity remains a challenge for the reproducibility of conventional imaging end-points and is an obstacle for research on novel imaging end-points. PATIENTS AND METHODS: Acknowledging the recently highlighted potential of radiomics and artificial intelligence tools as decision support for patient care in mCRC, a multidisciplinary, international and expert panel of imaging specialists was formed to find consensus on mCRC imaging protocols using the Delphi method. RESULTS: Under the guidance of the European Organisation for Research and Treatment of Cancer (EORTC) Imaging and Gastrointestinal Tract Cancer Groups, the European Society of Oncologic Imaging (ESOI) and the European Society of Gastrointestinal and Abdominal Radiology (ESGAR), the EORTC-ESOI-ESGAR core imaging protocol was identified. CONCLUSION: This consensus protocol attempts to promote standardisation and to diminish variations in patient preparation, scan acquisition and scan reconstruction. We anticipate that this standardisation will increase reproducibility of radiomics and artificial intelligence studies and serve as a catalyst for future research on imaging end-points. For ongoing and future mCRC trials, we encourage principal investigators to support the dissemination of these imaging standards across recruiting centres.

Imaging during pregnancy: What the radiologist needs to know.

During the last decades, there has been a growing demand for medical imaging in gravid women. Imaging of the pregnant woman is challenging as it involves both the mother and the fetus and, consequently, several medical, ethical, or legal considerations are likely to be raised. Theoretically, all currently available imaging modalities may be used for the evaluation of the pregnant woman; however, in practice, confusion regarding the safety of the fetus often results in unnecessary avoidance of useful diagnostic tests, especially those involving ionizing radiation. This review article is focused on the current safety guidelines and considerations regarding the use of different imaging modalities in the pregnant population; also presented is an imaging work-up for the most common medical conditions of pregnant women, with emphasis on fetal and maternal safety.

Twenty Years On: RECIST as a Biomarker of Response in Solid Tumours an EORTC Imaging Group - ESOI Joint Paper.

Response evaluation criteria in solid tumours (RECIST) v1.1 are currently the reference standard for evaluating efficacy of therapies in patients with solid tumours who are included in clinical trials, and they are widely used and accepted by regulatory agencies. This expert statement discusses the principles underlying RECIST, as well as their reproducibility and limitations. While the RECIST framework may not be perfect, the scientific bases for the anticancer drugs that have been approved using a RECIST-based surrogate endpoint remain valid. Importantly, changes in measurement have to meet thresholds defined by RECIST for response classification within thus partly circumventing the problems of measurement variability. The RECIST framework also applies to clinical patients in individual settings even though the relationship between tumour size changes and outcome from cohort studies is not necessarily translatable to individual cases. As reproducibility of RECIST measurements is impacted by reader experience, choice of target lesions and detection/interpretation of new lesions, it can result in patients changing response categories when measurements are near threshold values or if new lesions are missed or incorrectly interpreted. There are several situations where RECIST will fail to evaluate treatment-induced changes correctly; knowledge and understanding of these is crucial for correct interpretation. Also, some patterns of response/progression cannot be correctly documented by RECIST, particularly in relation to organ-site (e.g. bone without associated soft-tissue lesion) and treatment type (e.g. focal therapies). These require specialist reader experience and communication with oncologists to determine the actual impact of the therapy and best evaluation strategy. In such situations, alternative imaging markers for tumour response may be used but the sources of variability of individual imaging techniques need to be known and accounted for. Communication between imaging experts and oncologists regarding the level of confidence in a biomarker is essential for the correct interpretation of a biomarker and its application to clinical decision-making. Though measurement automation is desirable and potentially reduces the variability of results, associated technical difficulties must be overcome, and human adjudications may be required.

Diffusion-weighted imaging and texture analysis: current role for diffuse liver disease.

Multiparametric MRI represents the primary imaging modality to assess diffuse liver disease, both in a qualitative and in a quantitative manner. Diffusion-weighted imaging (DWI) is among the imaging techniques that can be used to assess fibrosis due to its unique capability to assess microstructural changes at the tissue level. DWI is based on water mobility patterns and has the potential to become a non-invasive and non-destructive virtual biopsy to assess diffuse liver disease, overcoming sampling bias errors due to its three-dimensional imaging capabilities. Parallel to DWI, another quantitative method called texture analysis may be used to assess early and advanced diffused liver disease through quantifying spatial relationships in a global and local level, applying to any type of digital imaging technique like MRI or CT. Initial results using texture analysis hold great promise. In the current paper, we will review the role of DWI and texture analysis using MR images in assessing diffuse liver disease.