Efficiency and Accuracy Evaluation of Multiple Diffusion-Weighted MRI Techniques Across Different Scanners.

BACKGROUND: The choice between different diffusion-weighted imaging (DWI) techniques is difficult as each comes with tradeoffs for efficient clinical routine imaging and apparent diffusion coefficient (ADC) accuracy. PURPOSE: To quantify signal-to-noise-ratio (SNR) efficiency, ADC accuracy, artifacts, and distortions for different DWI acquisition techniques, coils, and scanners. STUDY TYPE: Phantom, in vivo intraindividual biomarker accuracy between DWI techniques and independent ratings. POPULATION/PHANTOMS: NIST diffusion phantom. 51 Patients: 40 with prostate cancer and 11 with head-and-neck cancer at 1.5 T FIELD STRENGTH/SEQUENCE: Echo planar imaging (EPI): 1.5 T and 3 T Siemens; 3 T Philips. Distortion-reducing: RESOLVE (1.5 and 3 T Siemens); Turbo Spin Echo (TSE)-SPLICE (3 T Philips). Small field-of-view (FOV): ZoomitPro (1.5 T Siemens); IRIS (3 T Philips). Head-and-neck and flexible coils. ASSESSMENT: SNR Efficiency, geometrical distortions, and susceptibility artifacts were quantified for different b-values in a phantom. ADC accuracy/agreement was quantified in phantom and for 51 patients. In vivo image quality was independently rated by four experts. STATISTICAL TESTS: QIBA methodology for accuracy: trueness, repeatability, reproducibility, Bland-Altman 95% Limits-of-Agreement (LOA) for ADC. Wilcoxon Signed-Rank and student tests on P < 0.05 level. RESULTS: The ZoomitPro small FOV sequence improved b-image efficiency by 8%-14%, reduced artifacts and observer scoring for most raters at the cost of smaller FOV compared to EPI. The TSE-SPLICE technique reduced artifacts almost completely at a 24% efficiency cost compared to EPI for b-values ≤500 sec/mm2 . Phantom ADC 95% LOA trueness were within ±0.03 × 10-3 mm2 /sec except for small FOV IRIS. The in vivo ADC agreement between techniques, however, resulted in 95% LOAs in the order of ±0.3 × 10-3 mm2 /sec with up to 0.2 × 10-3 mm2 /sec of bias. DATA CONCLUSION: ZoomitPro for Siemens and TSE SPLICE for Philips resulted in a trade-off between efficiency and artifacts. Phantom ADC quality control largely underestimated in vivo accuracy: significant ADC bias and variability was found between techniques in vivo. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2.

[Contribution of whole-body MRI to the initial assessment of myxoid liposarcoma]. / Apport de l'IRM corps entier au bilan initial du liposarcome myxoïde.

INTRODUCTION: Myxoid liposarcoma is a soft tissue sarcoma associated with multifocal metastases at diagnosis. These metastases are asymptomatic and occult on CT and FDG-PET and can alter the therapeutic management and prognosis. In this context, we evaluated the contribution of whole-body MRI to the initial workup of patients with myxoid liposarcoma. METHOD: This retrospective study was conducted between January 2015 and December 2020 at the Oscar Lambret Center. We enrolled 22 patients who were diagnosed with myxoid liposarcoma and underwent whole-body MRI at diagnosis. The number of metastases at diagnosis, their location, and the visibility of these lesions on CT were evaluated. Associations between clinical features, presence of metastasis, and their impact on management were assessed. RESULTS: Sixteen patients (72.7%) had non-metastatic disease at the initial diagnosis, and 15 of these patients were managed using local treatment. Six patients (27.3%) had metastases at multiple locations and received chemotherapy. The main locations were the bones (n=5) and lungs (n=3). In five patients with metastases, whole-body MRI demonstrated additional lesions that were not visible on CT (bone and soft tissue lesions). Only the presence of a round cell contingent (P=0.009) was found as a criterion associated with the presence of metastases. CONCLUSION: The patients' young age, absence of reliable prognostic factors at diagnosis, asymptomatic nature of the lesions, and the benefits of early and targeted therapeutic management encourage the use of whole-body MRI as part of the initial work-up as it seems to provide a better initial staging compared with conventional imaging.

Diagnostic Value of the Texture Analysis Parameters of Retroperitoneal Residual Masses on Computed Tomographic Scan after Chemotherapy in Non-Seminomatous Germ Cell Tumors.

After chemotherapy, patients with non-seminomatous germ cell tumors (NSGCTs) with residual masses >1 cm on computed tomography (CT) undergo surgery. However, in approximately 50% of cases, these masses only consist of necrosis/fibrosis. We aimed to develop a radiomics score to predict the malignant character of residual masses to avoid surgical overtreatment. Patients with NSGCTs who underwent surgery for residual masses between September 2007 and July 2020 were retrospectively identified from a unicenter database. Residual masses were delineated on post-chemotherapy contrast-enhanced CT scans. Tumor textures were obtained using the free software LifeX. We constructed a radiomics score using a penalized logistic regression model in a training dataset, and evaluated its performance on a test dataset. We included 76 patients, with 149 residual masses; 97 masses were malignant (65%). In the training dataset (n = 99 residual masses), the best model (ELASTIC-NET) led to a radiomics score based on eight texture features. In the test dataset, the area under the curve (AUC), sensibility, and specificity of this model were respectively estimated at 0.82 (95%CI, 0.69-0.95), 90.6% (75.0-98.0), and 61.1% (35.7-82.7). Our radiomics score may help in the prediction of the malignant nature of residual post-chemotherapy masses in NSGCTs before surgery, and thus limit overtreatment. However, these results are insufficient to simply select patients for surgery.

Palpable Nodules After Autologous Fat Grafting in Breast Cancer Patients: Incidence and Impact on Follow-up.

INTRODUCTION: Autologous fat grafting (AFG) is a promising breast reconstruction technique, following surgery. However, fat necrosis after AFG can cause palpable nodules, inducing anxiety and prompting additional investigations. We aimed to determine the occurrence rate and to identify the risk factors of palpable nodules in breast cancer patients prompting complementary explorations. MATERIALS AND METHODS: We retrospectively reviewed the computerized files of consecutive breast cancer patients who underwent AFG after mastectomy or breast conservative treatment (BCT) at our center from January 2013 to December 2016. We collected data regarding palpable nodule incidences and suspicious breast imaging findings that led to additional explorations. RESULTS: Of the 252 patients reviewed, 222 (88%) underwent AFG for breast reconstruction, while 30 (12%) underwent AFG for correction of defects after BCT. The follow-up period ranged from 0 to 74 months (median: 27 months), and 201 patients had follow-ups beyond 1 year. Of the 252 patients, 66 (26.2%) underwent at least one control imaging and 24 (10%) underwent a biopsy, including 6 (2.4%) locoregional recurrence. Sixty patients (24%) were diagnosed with nodules during follow-ups. Among them, 52 (87%) patients had additional imaging, and 17 patients (28%) had a biopsy, including 82% benign histology. Patients with BCT had significantly more palpable nodules at 1 year than patients who underwent total mastectomy (odds ratio = 2.50, 95% confidence interval: 1.04. 6.03, p = 0.04). CONCLUSION: This study underlines the importance of preoperative patient information. This intervention and its follow-up should be reserved for experienced teams to limit unnecessary additional explorations. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

[French breast cancer screening: What's the place of artificial intelligence?] / Intelligence artificielle : Place dans le dépistage du cancer du sein en France.

This paper deals with the place in 2021 of artificial intelligence for screening of breast cancer in France et discusses of the different types of use and their performance in the literature (Standalone, Augmented radiologist, triage). Moreover, this paper will give an overview of the potential applications of AI in the future (Personalized screening, prediction of interval cancers).

[Second reading in breast cancer screening program: State of knowledge and future]. / Seconde lecture en dépistage organisé du cancer du sein. États des lieux et perspectives d'évolution.

Second reading is an important part of breast cancer organized screening program. Image quality control and detection of non-diagnosed cancer by first reader are the two goals of this process. In France, 6 % of all screening cancer are diagnosed by second reading, actually done on screen film. With the technologic evolution (Digital breast tomosynthesis, Artificial intelligence) and societal digitalization, this process need to evolve. After some report about organization and results for second reading in France and outside, current and future shortcomings, proposition from professionals involved in breast cancer screening are made to improve this public health program.

Technical note: Unexpected external markers artifact in 3D k-space based parallel imaging turbo spin-echo magnetic resonance imaging.

PURPOSE: MRI for radiotherapy planning requires spatial referencing using immobilization devices and markers. Clinical images of a difficult-to-interpret artifact are presented, resembling a metastasis, which occurs when combining CAIPIRINHA k-space-based parallel imaging (PI), 3D distortion correction, and external markers. METHODS: A 3D variable flip angle Turbo Spin Echo sequence was used on a 1.5 T and 3 T MRI using flexible and head and neck coils. Two types of markers were tested: Liquimark LM1 and Spee-D-Mark. A silicone oil phantom was used that represents low signal intensity, such as gray matter. 3D Fourier transforms were also used to show the issue's origin. RESULTS: The markers can appear in an unexpected region of a patient, not in the same original or reconstructed slice nor in a rectilinear direction in a slice, especially when using CAIPIRINHA acceleration with 3D distortion correction. The probability of occurrence was respectively 13% and 80% for distances of <=2 mm and >2 mm between marker and patient, for example when using thermoplastic masks. Clinical cases are shown where this semi-randomly occurring artifact appears post contrast only, and thus can be interpreted as metastases. The artifact did not appear when using compressed sensing acceleration. CONCLUSION: Markers used for radiotherapy MRI application can introduce additional artifacts that can be interpreted as metastases. However, other high signal intensity structures on the surface of a patient, such as the ear, can lead to an equivalent error.

Breast nodule classification with two-dimensional ultrasound using Mask-RCNN ensemble aggregation.

PURPOSE: The purpose of this study was to create a deep learning algorithm to infer the benign or malignant nature of breast nodules using two-dimensional B-mode ultrasound data initially marked as BI-RADS 3 and 4. MATERIALS AND METHODS: An ensemble of mask region-based convolutional neural networks (Mask-RCNN) combining nodule segmentation and classification were trained to explicitly localize the nodule and generate a probability of the nodule to be malignant on two-dimensional B-mode ultrasound. These probabilities were aggregated at test time to produce final results. Resulting inferences were assessed using area under the curve (AUC). RESULTS: A total of 460 ultrasound images of breast nodules classified as BI-RADS 3 or 4 were included. There were 295 benign and 165 malignant breast nodules used for training and validation, and another 137 breast nodules images used for testing. As a part of the challenge, the distribution of benign and malignant breast nodules in the test database remained unknown. The obtained AUC was 0.69 (95% CI: 0.57-0.82) on the training set and 0.67 on the test set. CONCLUSION: The proposed deep learning solution helps classify benign and malignant breast nodules based solely on two-dimensional ultrasound images initially marked as BIRADS 3 and 4.

Three artificial intelligence data challenges based on CT and ultrasound.

PURPOSE: The 2020 edition of these Data Challenges was organized by the French Society of Radiology (SFR), from September 28 to September 30, 2020. The goals were to propose innovative artificial intelligence solutions for the current relevant problems in radiology and to build a large database of multimodal medical images of ultrasound and computed tomography (CT) on these subjects from several French radiology centers. MATERIALS AND METHODS: This year the attempt was to create data challenge objectives in line with the clinical routine of radiologists, with less preprocessing of data and annotation, leaving a large part of the preprocessing task to the participating teams. The objectives were proposed by the different organizations depending on their core areas of expertise. A dedicated platform was used to upload the medical image data, to automatically anonymize the uploaded data. RESULTS: Three challenges were proposed including classification of benign or malignant breast nodules on ultrasound examinations, detection and contouring of pathological neck lymph nodes from cervical CT examinations and classification of calcium score on coronary calcifications from thoracic CT examinations. A total of 2076 medical examinations were included in the database for the three challenges, in three months, by 18 different centers, of which 12% were excluded. The 39 participants were divided into six multidisciplinary teams among which the coronary calcification score challenge was solved with a concordance index > 95%, and the other two with scores of 67% (breast nodule classification) and 63% (neck lymph node calcifications).

[Magnetic resonance imaging of desmoid-type fibromatosis: Current evaluation criteria]. / Imagerie par résonance magnétique des tumeurs desmoïdes : critères d'évaluations actuels.

The management of desmoid-type fibromatosis has considerably evolved these last years, toward first-line active surveillance then systemic or local symptomatic treatment in case of aggressive tumor. Magnetic resonance imaging is the modality of choice in each of these treatment settings. It needs multiparametric approach taking into account mainly the tumor size, and T2-weighted signal that is correlated with histological composition and clinical behavior. A volumetric approach should be favored for the evaluation of tumor size change. The interest of paramagnetic contrast injection and tumor enhancement requires further investigation.

[Breast cancer: News tools in imaging]. / Cancer du sein : la nouvelle imagerie.

Breast cancer imaging is always improving for the last 20 years in spite of digitalization and computer development. News tools in mammography (Digital Breast Tomosynthesis, Contrast enhanced mammography), sonography (elastography, Automated echography), MRI (Diffusion, abbreviated MRI) and Nuclear medicine has the great potential to be the future of breats imaging. But true revolution will be to use the huge volume of "hidden" imaging data, by Intelligence Artificial process or Biological progress (in genomics, proteiomics) to purpose to our patient a personalized imaging.

[French program of breast cancer screening: Radiologist viewpoint]. / Dépistage organisé du cancer du sein : point de vue du radiologue.

French program of breast cancer screening is implemented since15 years and results are in adequation with international guidelines except for participation. To answer to recurrent controversies about breast cancer screening, publications from National Institute of French cancer registry confirm the positive impact of screening on decreasing mortality for participating women. The harms of mammography (and not from screening) need to be communicated to the invited women to help them to make decision about participation but also the risk of worse prognosis in case of symptomatic cancer. The future of screening will be different and works are in progress to find new ways to select women who will beneficiate for screening and whose cancer needs to be treated. Until then, the only way to screen for breast cancer stays the mammographic process as well as other technics in case of dense breast or in case of family history of breast cancer.

Preoperative Breast Magnetic Resonance Imaging in Women With Local Ductal Carcinoma in Situ to Optimize Surgical Outcomes: Results From the Randomized Phase III Trial IRCIS.

PURPOSE: We evaluated the addition of breast magnetic resonance imaging (MRI) to standard radiologic evaluation on the re-intervention rate in women with ductal carcinoma in situ (DCIS) undergoing breast-conserving surgery. PATIENTS AND METHODS: Women with biopsy-proven DCIS corresponding to a unifocal microcalcification cluster or a mass less than 30 mm were randomly assigned to undergo MRI or standard evaluation. The primary end point was the re-intervention rate for positive or close margins (< 2 mm) in the 6 months after randomization ( ClinicalTrials.gov identifier: NCT01112254). RESULTS: A total of 360 patients from 10 hospitals in France were included in the study. Of the 352 analyzable patients, 178 were randomly assigned to the MRI arm, and 174 were assigned to the control arm. In the intent-to-treat analysis, 82 of 345 patients with the assessable end point were reoperated for positive or close margins within 6 months, resulting in a re-intervention rate of 20% (35 of 173) in the MRI arm and 27% (47 of 172) in the control arm. The absolute difference of 7% (95% CI, -2% to 16%) corresponded to a relative reduction of 26% (stratified odds ratio, 0.68; 95% CI, 0.41 to 1.1; P = .13). When considering only the per-protocol population with an assessable end point, the difference was 9% (stratified odds ratio, 0.59; 95% CI, 0.35 to 1.0; P = .05). Total mastectomy rates were 18% (31 of 176) in the MRI arm and 17% (30 of 173) in the control arm (stratified P = .93). For 100 lesions seen on MRI, nonmass-like enhancement was more predominant (82%) than mass enhancement (20%). Nevertheless, no specific morphologic and kinetic parameters for DCIS were identified. CONCLUSION: The study did not show sufficient surgical improvement with the use of preoperative MRI to be clinically relevant in DCIS staging. However, this could be reconsidered with the improvement of new MRI sequences and new modalities in magnetic resonance techniques.

[Ductal carcinoma in situ diagnosis: 3 French national guidelines]. / Diagnostic du carcinome canalaire in situ : 3 recommandations nationales françaises.

OBJECTIVE: Since the last guidelines published by the French National Cancer Institute (INCa) and the learning society "Société française de sénologie et de pathologie mammaire (SFSPM)" in 2009 about diagnosis and management of ductal carcinoma in situ, new data raised issues about overdiagnosis and its consequences, overtreatment. Therefore, an update was necessary, to provide healthcare professionals up-to-date guidelines and study therapeutic desescalation in particular. METHODS: The clinical practice guidelines development process is based on systematic literature review and critical appraisal by a multidisciplinary experts workgroup. The recommendations are thus based on the best available evidence and experts agreement. Prior to publication, the guidelines are also reviewed by more than 100 independent practitioners in cancer care delivery. RESULTS: This article presents French guidelines about MRI and vacuum assisted breast biopsy indications for DCIS diagnosis and the management of low-grade DCIS.

BIRADS 3 MRI lesions: Was the initial score appropriate and what is the value of the blooming sign as an additional parameter to better characterize these lesions?

OBJECTIVE: To investigate whether there were suspicious criteria on the initial MRI in BIRADS 3 lesions. To analyze the value of "blooming sign" as an additional criterion for malignancy. MATERIALS AND METHODS: In this retrospective study the lesion morphological and enhancement characteristics were analyzed. The "blooming sign" (BS), defined as the lesion size increase between the early and the late phase after gadolinium was assessed. We determined the optimal cut-off value for the BS to distinguish benign and malignant breast lesions. RESULTS: 100 lesions were classified BIRADS 3 in 75 patients (12%). Four of the five malignant lesions had suspicious BIRADS criteria on the index MRI. 45 lesions were stable and 30 lesions resolved spontaneously during the follow-up MRI. The optimal cut-off value for the BS was 8.54% with 100% sensitivity, 94% specificity, 44% positive and 100% negative predictive values. Using reclassification rule to upgrade benign BIRADS lesions with suspicious BS feature and downgrade suspicious BIRADS lesions with benign BS feature increased MRI specificity (89%), sensitivity (100%) while preserving NPV (100%). CONCLUSIONS: This study showed the suggestive part of classified BIRADS 3 lesions. The blooming sign seems to be a good additional parameter to increase MRI specificity when associated to BIRADS criteria.

Lobulated enhancement evaluation in the follow-up of liver metastases treated by stereotactic body radiation therapy.

OBJECTIVE: The Response Evaluation Criteria in Solid Tumors (RECIST) can have limitations when used to evaluate local treatments for cancer, especially for liver malignancies treated by stereotactic body radiation therapy (SBRT). The aim of this study was to validate the relationship between the occurrence of lobulated enhancement (LE) and local relapse and to evaluate the utility of this relationship for predicting local progression. PATIENTS AND METHODS: Imaging data of 59 lesions in 46 patients, including 281 computed tomographic (CT) scans, were retrospectively and blindly reviewed by 3 radiologists. One radiologist measured the lesion size, for each CT and overall, to classify responses using RECIST threshold criteria. The second studied LE occurrence. A third radiologist was later included and studied LE occurrence to evaluate the interobserver consistency for LE evaluation. RESULTS: The mean duration of follow-up was 13.6 months. LE was observed in 16 of 18 progressive lesions, occurring before size-based progression in 50% of cases, and the median delay of LE detection was 3.2 months. The sensitivity of LE to predict progression was 89%, and its specificity was 100%. The positive predictive value was 100%, the negative predictive value was 95.3%, and the overall accuracy was 97%. The probability of local progression-free survival at 12 months was significantly higher for lesions without LE compared with all lesions: 0.80 (CI 95%: 0.65-0.89) versus 0.69 (CI 95%: 0.54-0.80), respectively. The overall concordance rate between the 2 readers of LE was 97.9%. CONCLUSION: Response assessment of liver metastases treated by SBRT can be improved by including LE. This study demonstrates the diagnostic and predictive utility of LE for assessing local progression at a size still eligible for local salvage treatment.