Fast Ultrasound Scanning is a Rapid, Sensitive, Precise and Cost-Effective Method to Monitor Tumor Grafts in Mice.

In preclinical studies, accurate monitoring of tumor dynamics is crucial for understanding cancer biology and evaluating therapeutic interventions. Traditional methods like caliper measurements and bioluminescence imaging (BLI) have limitations, prompting the need for improved imaging techniques. This study introduces a fast-scan high-frequency ultrasound (HFUS) protocol for the longitudinal assessment of syngeneic breast tumor grafts in mice, comparing its performance with caliper, BLI measurements and with histological analysis. The E0771 mammary gland tumor cell line, engineered to express luciferase, was orthotopically grafted into immunocompetent C57BL/6 mice. Tumor growth was monitored longitudinally at multiple timepoints using caliper measurement, HFUS, and BLI, with the latter two modalities assessed against histopathological standards post-euthanasia. The HFUS protocol was designed for rapid, anesthesia-free scanning, focusing on volume estimation, echogenicity, and necrosis visualization. All mice developed tumors, only 20.6% were palpable at day 4. HFUS detected tumors as small as 2.2 mm in average diameter from day 4 post-implantation, with an average scanning duration of 47 s per mouse. It provided a more accurate volume assessment than caliper, with a lower average bias relative to reference tumor volume. HFUS also revealed tumor necrosis, correlating strongly with BLI in terms of tumor volume and cellularity. Notable discrepancies between HFUS and BLI growth rates were attributed to immune cell infiltration. The fast HFUS protocol enables precise and efficient tumor assessment in preclinical studies, offering significant advantages over traditional methods in terms of speed, accuracy, and animal welfare, aligning with the 3R principle in animal research.

MMP-11 expression in early luminal breast cancer: associations with clinical, MRI, pathological characteristics, and disease-free survival.

BACKGROUND: Early hormone-positive breast cancers typically have favorable outcomes, yet long-term surveillance is crucial due to the risk of late recurrences. While many studies associate MMP-11 expression with poor prognosis in breast cancer, few focus on early-stage cases. This study explores MMP-11 as an early prognostic marker in hormone-positive breast cancers. METHODS: In this retrospective study, 228 women with early hormone-positive invasive ductal carcinoma, treated surgically between 2011 and 2016, were included. MMP-11 expression was measured by immunohistochemistry, and its association with clinical and MRI data was analyzed. RESULTS: Among the patients (aged 31-89, median 60, with average tumor size of 15.7 mm), MMP-11 staining was observed in half of the cases. This positivity correlated with higher uPA levels and tumor grade but not with nodal status or size. Furthermore, MMP-11 positivity showed specific associations with MRI features. Over a follow-up period of 6.5 years, only 12 oncological events occurred. Disease-free survival was linked to Ki67 and MMP-11. CONCLUSION: MMP-11, primarily present in tumor-surrounding stromal cells, correlates with tumor grade and uPA levels. MMP-11 immunohistochemical score demonstrates a suggestive trend in association with disease-free survival, independent of Ki67 and other traditional prognostic factors. This highlights the potential of MMP-11 as a valuable marker in managing early hormone-positive breast cancer.

The Angers CT Score is a Risk Factor for the Failure of the Conservative Management of Adhesive Small Bowel Obstruction: A Prospective Observational Multicentric Study.

BACKGROUND: Identifying the 30% of adhesive small bowel obstructions (aSBO) for which conservative management will require surgery is essential. The association between the previously described radiological score and failure of the conservative management of aSBO remains to be confirmed in a large prospective multicentric cohort. Our aim was to assess the risk factors of failure of the conservative management of aSBO considering the radiological score. MATERIAL AND METHODS: This prospective observational study took place in 15 French centers over 3 months. Consecutive patients experiencing aSBO with no early surgery were included. The six radiological features from the Angers radiological computed tomography (CT) score were noted (beak sign, closed loop, focal or diffuse intraperitoneal liquid, focal or diffuse mesenteric haziness, focal or diffuse mesenteric liquid, and diameter of the most dilated small bowel loop > 40 mm). RESULTS: Two hundred and seventy nine patients with aSBO were screened. Sixty patients (21.5%) underwent early surgery, and 219 (78.5%) had primary conservative management. In the end, 218 patients were included in the analysis of the risk factors for conservative treatment failure. Among them, 162 (74.3%) had had successful management while for 56 (25.7%) management had failed. In multivariate analysis, a history of surgery was not a significant risk factor for the failure of conservative treatment (OR = 0.11; 95%CI = 0-1.23). A previous episode of aSBO was protective against the failure of conservative treatment (OR = 0.36; 95%CI = 0.15-0.85) and an Angers CT score ≥ 5 as the only individual risk factor (OR = 2.39; 95%CI = 1.01-5.69). CONCLUSION: The radiological score of aSBO is a promising tool in improving the management of aSBO patients. A first episode of aSBO and/or a radiological score ≥5 should lead physicians to consider early surgical management.

Roles of Matrix Metalloproteinases and Their Natural Inhibitors in Metabolism: Insights into Health and Disease.

Matrix metalloproteinases (MMPs) are a family of zinc-activated peptidases that can be classified into six major classes, including gelatinases, collagenases, stromelysins, matrilysins, membrane type metalloproteinases, and other unclassified MMPs. The activity of MMPs is regulated by natural inhibitors called tissue inhibitors of metalloproteinases (TIMPs). MMPs are involved in a wide range of biological processes, both in normal physiological conditions and pathological states. While some of these functions occur during development, others occur in postnatal life. Although the roles of several MMPs have been extensively studied in cancer and inflammation, their function in metabolism and metabolic diseases have only recently begun to be uncovered, particularly over the last two decades. This review aims to summarize the current knowledge regarding the metabolic roles of metalloproteinases in physiology, with a strong emphasis on adipose tissue homeostasis, and to highlight the consequences of impaired or exacerbated MMP actions in the development of metabolic disorders such as obesity, fatty liver disease, and type 2 diabetes.

Pre-operative CT scan helps predict outcome after liver transplantation for acute-on-chronic grade 3 liver failure.

OBJECTIVES: The aim of this study was to identify the prognostic value of pre-operative imaging to predict post-transplantation survival in critically ill cirrhotic patients with severe acute-on-chronic liver failure (ACLF). METHODS: Patients with grade 3 ACLF who underwent liver transplantation between January 2010 and January 2020 and with available contrast-enhanced abdominal computed tomography (CT) performed less than 3 months before LT were retrospectively included (n = 82). Primary endpoint was 1-year mortality. Imaging parameters (sarcopenia, liver morphology and volumetry, and signs of portal hypertension) were screened and tested to build a prognostic score. RESULTS: In the multivariate analysis, three independent CT-derived prognostic factors were found: splenomegaly (p = 0.021; HR = 5.6 (1.29-24.1)), liver atrophy (p = 0.05; HR = 2.93 (1.01-10.64)), and vena cava diameter ratio (p < 0.0001; HR = 12.7 (3.4-92)). A simple prognostic score was proposed, based on the presence of splenomegaly (5 points), liver atrophy (5 points), and vena cava diameter ratio < 0.2 (12 points). A cutoff at 10 points distinguished a high-risk group (score > 10) from a low-risk group (score ≤ 10) with 1-year survival of 27% vs. 67% respectively (p < 0.001). It was found to be an independent predictive factor in association with the Transplantation for ACLF3 Model (TAM) score. CONCLUSION: Pre-transplantation contrast-enhanced abdominal CT has a significant impact on selection of patients in ACLF3 in order to predict 1-year survival after LT. KEY POINTS: • Splenomegaly, liver atrophy, and vena cava diameter ratio are independent CT-derived prognostic factors after transplantation for severe acute-on-chronic liver failure. • A simple CT-based prognostic score is an independent predictive factor, complementary to clinical and biological parameters. • The use of the CT-derived score allows stratification based on 1-year mortality for patients with otherwise uncertain prognosis with clinical and biological parameters alone.

Study of Thoracic CT in COVID-19: The STOIC Project.

Background There are conflicting data regarding the diagnostic performance of chest CT for COVID-19 pneumonia. Disease extent at CT has been reported to influence prognosis. Purpose To create a large publicly available data set and assess the diagnostic and prognostic value of CT in COVID-19 pneumonia. Materials and Methods This multicenter, observational, retrospective cohort study involved 20 French university hospitals. Eligible patients presented at the emergency departments of the hospitals involved between March 1 and April 30th, 2020, and underwent both thoracic CT and reverse transcription-polymerase chain reaction (RT-PCR) testing for suspected COVID-19 pneumonia. CT images were read blinded to initial reports, RT-PCR, demographic characteristics, clinical symptoms, and outcome. Readers classified CT scans as either positive or negative for COVID-19 based on criteria published by the French Society of Radiology. Multivariable logistic regression was used to develop a model predicting severe outcome (intubation or death) at 1-month follow-up in patients positive for both RT-PCR and CT, using clinical and radiologic features. Results Among 10 930 patients screened for eligibility, 10 735 (median age, 65 years; interquartile range, 51-77 years; 6147 men) were included and 6448 (60%) had a positive RT-PCR result. With RT-PCR as reference, the sensitivity and specificity of CT were 80.2% (95% CI: 79.3, 81.2) and 79.7% (95% CI: 78.5, 80.9), respectively, with strong agreement between junior and senior radiologists (Gwet AC1 coefficient, 0.79). Of all the variables analyzed, the extent of pneumonia at CT (odds ratio, 3.25; 95% CI: 2.71, 3.89) was the best predictor of severe outcome at 1 month. A score based solely on clinical variables predicted a severe outcome with an area under the curve of 0.64 (95% CI: 0.62, 0.66), improving to 0.69 (95% CI: 0.6, 0.71) when it also included the extent of pneumonia and coronary calcium score at CT. Conclusion Using predefined criteria, CT reading is not influenced by reader's experience and helps predict the outcome at 1 month. ClinicalTrials.gov identifier: NCT04355507 Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Rubin in this issue.

Acute Pulmonary Embolism in Patients with COVID-19 at CT Angiography and Relationship to d-Dimer Levels.

Online supplemental material is available for this article.

A novel machine learning-derived decision tree including uPA/PAI-1 for breast cancer care.

Background uPA and PAI-1 are breast cancer biomarkers that evaluate the benefit of chemotherapy (CT) for HER2-negative, estrogen receptor-positive, low or intermediate grade patients. Our objectives were to observe clinical routine use of uPA/PAI-1 and to build a new therapeutic decision tree integrating uPA/PAI-1. Methods We observed the concordance between CT indications proposed by a canonical decision tree representative of French practices (not including uPA/PAI-1) and actual CT prescriptions decided by a medical board which included uPA/PAI-1. We used a method of machine learning for the analysis of concordant and non-concordant CT prescriptions to generate a novel scheme for CT indications. Results We observed a concordance rate of 71% between indications proposed by the canonical decision tree and actual prescriptions. Discrepancies were due to CT contraindications, high tumor grade and uPA/PAI-1 level. Altogether, uPA/PAI-1 were a decisive factor for the final decision in 17% of cases by avoiding CT prescription in two-thirds of cases and inducing CT in other cases. Remarkably, we noted that in routine practice, elevated uPA/PAI-1 levels seem not to be considered as a sufficient indication for CT for N≤3, Ki 67≤30% tumors, but are considered in association with at least one additional marker such as Ki 67>14%, vascular invasion and ER-H score <150. Conclusions This study highlights that in the routine clinical practice uPA/PAI-1 are never used as the sole indication for CT. Combined with other routinely used biomarkers, uPA/PAI-1 present an added value to orientate the therapeutic choice.

Case 254: Posttraumatic Migrating Fat Embolus Causing Fat Emboli Syndrome.

History An otherwise healthy 18-year-old man was admitted to the emergency department with a closed displaced fracture of the left femoral shaft ( Fig 1 ) after a high-velocity motorbike accident. At admission, other physical examination findings were unremarkable. Initial unenhanced and contrast material-enhanced (120 mL of Iomeron 400; Bracco Imaging, Milan, Italy) computed tomography (CT) was performed in the arterial and venous phases from the head to the knees. No abnormalities were noted in the brain or chest at initial CT. [Figure: see text] Within a few hours, the patient developed sudden mental confusion and severe hypoxemia, with rapidly worsening tachypnea and perturbed arterial blood gas with low partial pressure of oxygen (61 mmHg [8.1 kPa]; normal range, 75-100 mmHg [10.0-13.3 kPa]) and low partial pressure of carbon dioxide (32 mmHg [4.3 kPa]; normal range, 38-42 mmHg [5.1-5.6 kPa]). A second contrast-enhanced chest CT examination and initial brain magnetic resonance (MR) imaging were performed. Femoral fracture was stabilized with external fixation, and the patient was admitted to the intensive care unit, with progressive neurologic recovery at day 3 and respiratory improvement at day 4. Treatment included intubation with mechanical ventilation and intravenous administration of steroids and noradrenaline. Afterward, the femoral fracture was stabilized with an intramedullary nail. The patient made a full neurologic recovery 1 month after the accident.

Evaluation of Paraspinal Fat Pad as an Indicator of Posterior Ligamentous Complex Injury in Cervical Spine Trauma.

Purpose To determine if the obliteration of a cervical space, the paraspinal fat pad (PFP), can be used as an indicator at computed tomography (CT) of an injury of cervical spine posterior ligamentous complex (PLC). Materials and Methods This retrospective study was approved by the institutional board review; written informed consent was obtained from healthy subjects and was waived for patients. First, PFP appearance was evaluated in an anatomic specimen and in 10 healthy subjects on spine CT scans by three radiologists (readers 1, 2, and 3) working in consensus. Then, in 85 patients with suspicion of cervical spine trauma following high-velocity trauma, readers 2 and 3 reviewed in consensus the cervical spine CT (reference for fracture and luxation) and 1.5-T magnetic resonance images (T1, T2, and short inversion time inversion-recovery sequences; reference for ligament and disk injuries and contusion or occult fracture) for traumatic injuries. CT appearance of PFP was independently analyzed by readers 1 and 2, and interobserver agreement (weighted kappa) was calculated. Relationships between PFP changes and injuries and descriptive analysis were calculated by using logistic regression and Fisher test, respectively. Results The PFP could be identified as a well-circumscribed fatty area between cervical spine and posterior muscles. Interobserver agreement was 0.76. An abnormal PFP was associated with PLC (P < .001) and arch (P = .006) injuries but not with body (P = .056), longitudinal ligaments (P = .412), or disk (P = .665) injuries. Sensitivity, specificity, positive predictive value, and negative predictive value for PLC injuries were 55% (11 of 20), 97% (38 of 39), 92% (11 of 12), and 81% (38 of 47), respectively. Conclusion PFP changes on CT scans are significantly associated with injuries of PLC in patients with spine cervical trauma. © RSNA, 2016 Online supplemental material is available for this article.

Medical treatment of mammary desmoid-type fibromatosis: which benefit?

BACKGROUND: Breast fibromatosis is a rare disease characterized by monoclonal fibroblast proliferation. It has no ability to metastasize but has a high local recurrence rate and often infiltrates surrounding tissues. Surgical treatment is the reference, but recently, new targeted therapies have emerged. We report an original case of a patient with breast fibromatosis who received exclusive medical treatment. Our aim was to analyze these treatments based on the clinical and radiological outcome, iatrogenic effects, and pharmacological action. CASE PRESENTATION: We report the case of a 19-year-old woman who developed a desmoid-type fibromatosis of the lower inner quadrant of the right breast, measuring 50 × 25 mm (i.e., a volume of 27.4 cm3). Initial surgery was not possible because of potential esthetic and functional prejudice. Thus, she had an exclusive medical treatment including several lines: NSAIDs with tamoxifen and triptorelin, followed by sorafenib, then interferon α2b, and finally sunitinib. With tyrosine-kinase inhibitors (TKIs) (sunitinib), a significant partial response was observed (57% reduction of the maximal tumoral volume). For each treatment, we provided the clinical and radiological outcome in association with known pharmacological action. CONCLUSIONS: TKI had been an interesting alternative option to initial surgery, providing at least a partial response and potentially allowing less mutilating surgery. However, no pharmacological mechanism can unequivocally explain TKI efficacy. In general, breast fibromatosis should be treated along with oncologist and interventional radiologists in a trans-disciplinary modality, thus offering an adapted treatment for this particular desmoid-type fibromatosis localization.

Relevance of breast MRI in determining the size and focality of invasive breast cancer treated by mastectomy: a prospective study.

BACKGROUND: The aim of this study was the evaluation of breast MRI in determining the size and focality of invasive non-metastatic breast cancers. METHODS: The prospective, single-centre study conducted in 2015 compared preoperative MRI with histological analysis of mastectomy. RESULTS: One hundred one mastectomies from 98 patients were extensively analysed. The rates of false-positive and false-negative MRI were 2 and 4% respectively. The sensitivity of breast MRI was 84.7% for the detection of all invasive foci, 69% for single foci and 65.7% for multiple foci. In the evaluation of tumour size, the Spearman rank correlation coefficient r between the sizes obtained by MRI and histology was 0.62. The MRI-based prediction of a complete response to neoadjuvant chemotherapy was 75%. DISCUSSION: MRI exhibits high sensitivity in the detection of invasive breast cancers. False positives were linked to the inflammatory nature of the tumour bed. False negatives were associated with small or low-grade tumours and their retro-areolar location. The size of T1 tumours was overestimated by an average of 7%, but MRI was the most efficient procedure. The sensitivity of MRI for the diagnosis of unifocal tumours was higher than that for multifocal sites. Our study confirmed the positive contribution of preoperative MRI for invasive lobular carcinomas and complete response predictions after neoadjuvant chemotherapy.

Comparative study of fat-suppression techniques for hip arthroplasty MR imaging.

OBJECTIVES: The goal of this study was to evaluate different fat-suppressed fluid-sensitive sequences in association with different metal artifacts reduction techniques (MARS) to determine which combination allows better fat suppression around metallic hip implants. METHODS: An experimental study using an MRI fat-water phantom quantitatively evaluated contrast shift induced by metallic hip implant for different fat-suppression techniques and MARS. Then a clinical study with patients addressed to MRI unit for painful hip prosthesis compared these techniques in terms of fat suppression quality and diagnosis confidence. RESULTS: Among sequences without MARS, both T2 Dixon and short tau inversion recuperation (STIR) had significantly lower contrast shift (p < 0.05), Dixon offering the best fat suppression. Adding MARS (view-angle tilting or slice-encoding for metal artifact correction (SEMAC)) to STIR gave better results than Dixon alone, and also better than SPAIR and fat saturation with MARS (p < 0.05). There were no statistically significant differences between STIR with view-angle tilting and STIR with SEMAC in terms of fat suppression quality. CONCLUSIONS: STIR sequence is the preferred fluid-sensitive MR sequence in patients with metal implant. In combination with MARS (view-angle tilting or SEMAC), STIR appears to be the best option for high-quality fat suppression.

Usefulness of diffusion-weighted imaging for diagnosis of adrenal ischemia during pregnancy: a preliminary report.

This case report aims to illustrate the clinical usefulness of diffusion-weighted imaging for diagnosis of bilateral adrenal ischemia during pregnancy. We also provide a retrospective analysis of adrenal gland diffusion data in a control group of 12 pregnant women with no adrenal dysfunction, to assess the normal range of apparent diffusion coefficient of adrenal gland during pregnancy.

A prospective study to assess the clinical utility of serum HER2 extracellular domain in breast cancer with HER2 overexpression.

PURPOSE: We explored the clinical utility of human epidermal growth factor receptor-2 extracellular domain (HER2/ECD) in patients treated for an invasive breast cancer with HER2 overexpression. METHODS: We prospectively studied HER2/ECD levels in the sera of 334 women included between 2007 and 2014, all treated with trastuzumab. HER2/ECD levels were measured at diagnosis, during treatments, and along the follow-up. We investigated the relationship of HER2/ECD with other clinicopathological parameters at diagnosis, its prognosis value, and its utility during the monitoring of a neoadjuvant treatment and the follow-up. RESULTS: Elevated HER2/ECD at diagnosis correlated positively with parameters associated with tumor aggressiveness. Disease-free survival of non-metastatic patients was significantly shorter in patients with high HER2/ECD at diagnosis (HR = 13.6, 95 % CI 1.6-113.6, P < 0.0001). Progression-free survival of metastatic patients was better for patients with low HER2/ECD (HR = 2.6, 95 % CI 1.2-5.3, P = 0.033). A multivariate analysis revealed that HER2/ECD level at diagnosis was an independent prognosis factor. During neoadjuvant therapy, a significant decrease in HER2/ECD was reported only for the complete histological response group (P = 0.031). During the follow-up, HER2/ECD helped predict relapse, disease progression, and metastases before imaging in 18.6 % cases of the studied cohort. CONCLUSIONS: HER2/ECD is a prognosis factor that is valuable in evaluating the neoadjuvant treatment efficiency. HER2/ECD also appears to be a helpful surveillance biomarker for the early diagnosis of relapses and to predict the fate of metastases. This study brings evidences to support the use of HER2/ECD in the management of HER2-positive breast cancer.

[Can we avoid axillary lymph node dissection in patients with node positive invasive breast carcinoma?] / Peut-on surseoir au curage axillaire en cas de carcinome mammaire invasif avec envahissement ganglionnaire ?

OBJECTIVES: The indications and modalities of breast and axillary surgery are undergoing profound change, with the aim of personalizing surgical management while avoiding over-treatment. To update best practices for axillary surgery, four questions were selected by the Senology Commission of the Collège National des Gynécologues et Obstétriciens Français (CNGOF), focusing on, firstly, the definition and evaluation of targeted axillary dissection (TAD) techniques; secondly, the possibility of surgical de-escalation in case of initial lymph node involvement while performing initial surgery; thirdly, in case of surgery following neo-adjuvant systemic therapy (NAST), and fourthly, contra-indications to de-escalation of axillary surgery to allow access to particular adjuvant systemic therapies. METHODS: The Senology Commission based its responses primarily on an analysis of the international literature, clinical practice recommendations and national and international guidelines. RESULTS: Firstly, TAD is a technique that combines excision of clipped metastatic axillary node(s) and the axillary sentinel lymph nodes (ASLNs). The detection rate and sensitivity are increased but it still needs to be standardized and practices better evaluated. Secondly, TAD represents an alternative to axillary clearance in cases of metastatic involvement of a single node that can be resected. Thirdly, neither TAD nor ASLN alone is recommended in France after NAST outside of clinical trials, although it is used in several countries in cases of complete pathological response in the lymph nodes, and when at least three lymph nodes have been removed. Fourthly, as some adjuvant targeted therapies are indicated in cases of lymph node invasion of more than three lymph nodes, the place of TAD in this context remains to be defined. CONCLUSION: Axillary surgical de-escalation can limit the morbidity of axillary clearance. Having proved that TAD does not reduce patient survival, it will most probably replace axillary clearance in well-defined indications. This will require prior standardization of the method and its indications and contra-indications, particularly to enable the use of new targeted therapies.

[Updated surgical indications and quality and safety indicators in the management of infiltrative breast carcinoma]. / Actualisation des indications chirurgicales et des indicateurs de qualité et sécurité des soins dans la prise en charge des carcinomes mammaires invasifs.

OBJECTIVES: Breast surgery is the cornerstone of breast cancer treatment. Its indications and procedures are constantly evolving. To update best practices, four questions were submitted to the Senology Commission (SC) of the Collège national des gynécologues et obstétriciens français (CNGOF), covering the indications and modalities of tumor surgery: (1) initially, (2) following neoadjuvant systemic treatment, (3) in case of local recurrence, and (4) the quality and safety of care indicators applicable to this surgery. METHODS: The CNGOF SC essentially based its responses on the clinical practice recommendations and guidelines of the French Cancer Institute concerning invasive carcinomas of the breast. Exclusion criteria were carcinoma in situ, sarcoma and axillary surgery. RESULTS: To define the type of breast surgery, knowledge of four parameters is essential: the patient's level of risk, the presence of metastases, the size of the breast tumor and its focality (assessed by the clinical/mammography/ultrasound tripod). (1) In the case of initial management, the 6 indications for mastectomy are patient choice (particularly in case of high risk), contraindication to radiotherapy, inflammatory cancer (T4d), surgery with positive margins (after several surgical intervention), surgery that cannot be performed as a monobloc in the case of tumors with multiple foci, and poor expected aesthetic results. All other situations should be treated conservatively. (2) The same criteria apply after neoadjuvant systemic treatment, with conservative treatment still possible whatever the size (excluding carcinomatous mastitis) and focality of the initial tumor. (3) In case of local recurrence, total mastectomy is the reference treatment, with a second conservative treatment reserved for patients with no risk factors for a second recurrence, and no poor prognostic factors, after validation in a multidisciplinary meeting. (4) Four quality and safety indicators apply to breast surgery: it must be performed after obtaining a histological diagnosis, within less than 6 weeks of mammography, in a single surgery in over 80% of cases, and followed by local radiotherapy in the case of conservative treatment. CONCLUSION: The indications and modalities of breast surgery are evolving rapidly. To improve aesthetic results, oncoplastic techniques, immediate breast reconstruction, and preservation of the skin or nipple-areolar complex need to be further developed and evaluated in the long-term. These developments must necessarily be accompanied in France by a training policy for breast surgeons.

Reference standard for the evaluation of automatic segmentation algorithms: Quantification of inter observer variability of manual delineation of prostate contour on MRI.

PURPOSE: The purpose of this study was to investigate the relationship between inter-reader variability in manual prostate contour segmentation on magnetic resonance imaging (MRI) examinations and determine the optimal number of readers required to establish a reliable reference standard. MATERIALS AND METHODS: Seven radiologists with various experiences independently performed manual segmentation of the prostate contour (whole-gland [WG] and transition zone [TZ]) on 40 prostate MRI examinations obtained in 40 patients. Inter-reader variability in prostate contour delineations was estimated using standard metrics (Dice similarity coefficient [DSC], Hausdorff distance and volume-based metrics). The impact of the number of readers (from two to seven) on segmentation variability was assessed using pairwise metrics (consistency) and metrics with respect to a reference segmentation (conformity), obtained either with majority voting or simultaneous truth and performance level estimation (STAPLE) algorithm. RESULTS: The average segmentation DSC for two readers in pairwise comparison was 0.919 for WG and 0.876 for TZ. Variability decreased with the number of readers: the interquartile ranges of the DSC were 0.076 (WG) / 0.021 (TZ) for configurations with two readers, 0.005 (WG) / 0.012 (TZ) for configurations with three readers, and 0.002 (WG) / 0.0037 (TZ) for configurations with six readers. The interquartile range decreased slightly faster between two and three readers than between three and six readers. When using consensus methods, variability often reached its minimum with three readers (with STAPLE, DSC = 0.96 [range: 0.945-0.971] for WG and DSC = 0.94 [range: 0.912-0.957] for TZ, and interquartile range was minimal for configurations with three readers. CONCLUSION: The number of readers affects the inter-reader variability, in terms of inter-reader consistency and conformity to a reference. Variability is minimal for three readers, or three readers represent a tipping point in the variability evolution, with both pairwise-based metrics or metrics with respect to a reference. Accordingly, three readers may represent an optimal number to determine references for artificial intelligence applications.