A Framework of Analysis to Facilitate the Harmonization of Multicenter Radiomic Features in Prostate Cancer.

Pooling radiomic features coming from different centers in a statistical framework is challenging due to the variability in scanner models, acquisition protocols, and reconstruction settings. To remove technical variability, commonly called batch effects, different statistical harmonization strategies have been widely used in genomics but less considered in radiomics. The aim of this work was to develop a framework of analysis to facilitate the harmonization of multicenter radiomic features extracted from prostate T2-weighted magnetic resonance imaging (MRI) and to improve the power of radiomics for prostate cancer (PCa) management in order to develop robust non-invasive biomarkers translating into clinical practice. To remove technical variability and correct for batch effects, we investigated four different statistical methods (ComBat, SVA, Arsynseq, and mixed effect). The proposed approaches were evaluated using a dataset of 210 prostate cancer (PCa) patients from two centers. The impacts of the different statistical approaches were evaluated by principal component analysis and classification methods (LogitBoost, random forest, K-nearest neighbors, and decision tree). The ComBat method outperformed all other methods by achieving 70% accuracy and 78% AUC with the random forest method to automatically classify patients affected by PCa. The proposed statistical framework enabled us to define and develop a standardized pipeline of analysis to harmonize multicenter T2W radiomic features, yielding great promise to support PCa clinical practice.

Evaluation of a multiparametric MRI radiomic-based approach for stratification of equivocal PI-RADS 3 and upgraded PI-RADS 4 prostatic lesions.

Despite the key-role of the Prostate Imaging and Reporting and Data System (PI-RADS) in the diagnosis and characterization of prostate cancer (PCa), this system remains to be affected by several limitations, primarily associated with the interpretation of equivocal PI-RADS 3 lesions and with the debated role of Dynamic Contrast Enhanced-Magnetic Resonance Imaging (DCE-MRI), which is only used to upgrade peripheral PI-RADS category 3 lesions to PI-RADS category 4 if enhancement is focal. We aimed at investigating the usefulness of radiomics for detection of PCa lesions (Gleason Score ≥ 6) in PI-RADS 3 lesions and in peripheral PI-RADS 3 upgraded to PI-RADS 4 lesions (upPI-RADS 4). Multiparametric MRI (mpMRI) data of patients who underwent prostatic mpMRI between April 2013 and September 2018 were retrospectively evaluated. Biopsy results were used as gold standard. PI-RADS 3 and PI-RADS 4 lesions were re-scored according to the PI-RADS v2.1 before and after DCE-MRI evaluation. Radiomic features were extracted from T2-weighted MRI (T2), Apparent diffusion Coefficient (ADC) map and DCE-MRI subtracted images using PyRadiomics. Feature selection was performed using Wilcoxon-ranksum test and Minimum Redundancy Maximum Relevance (mRMR). Predictive models were constructed for PCa detection in PI-RADS 3 and upPI-RADS 4 lesions using at each step an imbalance-adjusted bootstrap resampling (IABR) on 1000 samples. 41 PI-RADS 3 and 32 upPI-RADS 4 lesions were analyzed. Among 293 radiomic features, the top selected features derived from T2 and ADC. For PI-RADS 3 stratification, second order model showed higher performances (Area Under the Receiver Operating Characteristic Curve-AUC- = 80%), while for upPI-RADS 4 stratification, first order model showed higher performances respect to superior order models (AUC = 89%). Our results support the significant role of T2 and ADC radiomic features for PCa detection in lesions scored as PI-RADS 3 and upPI-RADS 4. Radiomics models showed high diagnostic efficacy in classify PI-RADS 3 and upPI-RADS 4 lesions, outperforming PI-RADS v2.1 performance.

Dual energy computed tomography evaluation of skeletal traumas.

Skeletal traumas are among the most common routine challenges faced by Emergency Radiologists, in particular in case of radiographically occult nondisplaced fractures or in case of soft tissue injuries. With the development of Dual Energy Computed Tomography (DECT) technology, new post-processing applications have gained a useful diagnostic role in many fields of musculoskeletal imaging including acute skeletal trauma imaging. In addition to conventional CT images, DECT allows for the generation of virtual calcium-suppressed images subtracting calcium from unenhanced CT images based on the fact that material attenuation varies at different energy levels. In this way, virtual-non-calcium (VNC) images can precisely characterize traumatic bone marrow edema in both axial and appendicular skeleton, facilitating prompt clinical decision, especially when magnetic resonance method is contraindicated or unavailable. Other DECT emerging applications in the trauma setting include metal artifact reduction and collagen mapping for the evaluation of injuries affecting ligament, tendon, and intervertebral disk. This review focuses on the basic principles of DECT and related post-processing algorithms, highlighting the current advantages and limitations of these new imaging advances in the Emergency Department related to skeletal traumas.

Assessment of DCE Utility for PCa Diagnosis Using PI-RADS v2.1: Effects on Diagnostic Accuracy and Reproducibility.

The role of dynamic contrast-enhanced-MRI (DCE-MRI) for Prostate Imaging-Reporting and Data System (PI-RADS) scoring is a controversial topic. In this retrospective study, we aimed to measure the added value of DCE-MRI in combination with T2-weighted (T2W) and diffusion-weighted imaging (DWI) using PI-RADS v2.1, in terms of reproducibility and diagnostic accuracy, for detection of prostate cancer (PCa) and clinically significant PCa (CS-PCa, for Gleason Score ≥ 7). 117 lesions in 111 patients were identified as suspicion by multiparametric MRI (mpMRI) and addressed for biopsy. Three experienced readers independently assessed PI-RADS score, first using biparametric MRI (bpMRI, including DWI and T2W), and then multiparametric MRI (also including DCE). The inter-rater and inter-method agreement (bpMRI- vs. mpMRI-based scores) were assessed by Cohen's kappa (κ). Receiver operating characteristics (ROC) analysis was performed to evaluate the diagnostic accuracy for PCa and CS-PCa detection among the two scores. Inter-rater agreement was excellent for the three pairs of readers (κ ≥ 0.83), while the inter-method agreement was good (κ ≥ 0.73). Areas under the ROC curve (AUC) showed similar high-values (0.8 ≤ AUC ≤ 0.85). The reproducibility of PI-RADS v2.1 scoring was comparable and high among readers, without relevant differences, depending on the MRI protocol used. The inclusion of DCE did not influence the diagnostic accuracy.

Multiparametric MRI for Prostate Cancer Detection: New Insights into the Combined Use of a Radiomic Approach with Advanced Acquisition Protocol.

Prostate cancer (PCa) is a disease affecting an increasing number of men worldwide. Several efforts have been made to identify imaging biomarkers to non-invasively detect and characterize PCa, with substantial improvements thanks to multiparametric Magnetic Resonance Imaging (mpMRI). In recent years, diffusion kurtosis imaging (DKI) was proposed to be directly related to tissue physiological and pathological characteristic, while the radiomic approach was proven to be a key method to study cancer imaging phenotypes. Our aim was to compare a standard radiomic model for PCa detection, built using T2-weighted (T2W) and Apparent Diffusion Coefficient (ADC), with an advanced one, including DKI and quantitative Dynamic Contrast Enhanced (DCE), while also evaluating differences in prediction performance when using 2D or 3D lesion segmentation. The obtained results in terms of diagnostic accuracy were high for all of the performed comparisons, reaching values up to 0.99 for the area under a receiver operating characteristic curve (AUC), and 0.98 for both sensitivity and specificity. In comparison, the radiomic model based on standard features led to prediction performances higher than those of the advanced model, while greater accuracy was achieved by the model extracted from 3D segmentation. These results provide new insights into active topics of discussion, such as choosing the most convenient acquisition protocol and the most appropriate postprocessing pipeline to accurately detect and characterize PCa.

The use of chest ultrasonography in suspected cases of COVID-19 in the emergency department.

AIM: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus-specific reverse transcriptase-polymerase chain reaction (RT-PCR) represents the diagnostic gold standard. We explored the value of chest ultrasonography to predict positivity to SARS-CoV-2 on RT-PCR in suspected COVID-19 cases. PATIENTS & METHODS: Consecutive patients with suspect COVID-19 were included if they had fever and/or history of cough and/or dyspnea. Lung ultrasound score (LUSS) was computed according to published methods. RESULTS: A total of 76 patients were included. A 3-variable model based on aspartate transaminase (AST) > upper limit of normal, LUSS >12 and body temperature >37.5°C yielded an overall accuracy of 91%. CONCLUSION: A simple LUSS-based model may represent a powerful tool for initial assessment in suspected cases of COVID-19.

Long-term improvement in cardiac magnetic resonance in ß-thalassemia major patients treated with deferasirox extends to patients with abnormal baseline cardiac function.

The management of iron overload in thalassemia has changed dramatically since the implementation of magnetic resonance imaging, which allows detection of preclinical iron overload and prevention of clinical complications. This study evaluated the effect of deferasirox (DFX), the newest once-daily oral chelator, on cardiac function, iron overload and cardiovascular events over a longer follow up in a "real world" setting. Longitudinal changes in cardiac magnetic resonance T2*, cardiac function parameters and cardiovascular clinical events were assessed in a cohort of 98 TM patients exposed to DFX for a mean of 6.9 years (range 1.8-11.6 years). No cardiac death or incident heart failure occurred. Cardiac T2* significantly increased (+2.6 ± 11.9 msec; P = 0.035) in the whole population, with a significantly greater increase (+11.6 ± 15.5 msec, P = 0.019) in patients with cardiac iron overload (T2* <20 ms). A significant improvement in left-ventricular ejection fraction (LVEF) (from 50.6 ± 6 to 60.2 ± 5; P = 0.001) was observed in 11 (84.6%) out of 13 patients who normalized cardiac function (LVEF >56%). Arrhythmias were the most frequent cardiac adverse event noted but none led to DFX discontinuation. Our data indicate that DFX is effective in maintaining cardiac iron level in the normal range and in improving cardiac iron overload. No heart failure or cardiac death was reported over this longer observation up to 12 years. For the first time, a DFX-induced improvement in LVEF was observed in a subgroup of patients with abnormal cardiac function at baseline, a preliminary observation which deserves further evaluation.

Contrast-Enhanced Magnetic Resonance Cholangiography: Practical Tips and Clinical Indications for Biliary Disease Management.

Since its introduction, MRCP has been improved over the years due to the introduction of several technical advances and innovations. It consists of a noninvasive method for biliary tree representation, based on heavily T2-weighted images. Conventionally, its protocol includes two-dimensional single-shot fast spin-echo images, acquired with thin sections or with multiple thick slabs. In recent years, three-dimensional T2-weighted fast-recovery fast spin-echo images have been added to the conventional protocol, increasing the possibility of biliary anatomy demonstration and leading to a significant benefit over conventional 2D imaging. A significant innovation has been reached with the introduction of hepatobiliary contrasts, represented by gadoxetic acid and gadobenate dimeglumine: they are excreted into the bile canaliculi, allowing the opacification of the biliary tree. Recently, 3D interpolated T1-weighted spoiled gradient echo images have been proposed for the evaluation of the biliary tree, obtaining images after hepatobiliary contrast agent administration. Thus, the acquisition of these excretory phases improves the diagnostic capability of conventional MRCP-based on T2 acquisitions. In this paper, technical features of contrast-enhanced magnetic resonance cholangiography are briefly discussed; main diagnostic tips of hepatobiliary phase are showed, emphasizing the benefit of enhanced cholangiography in comparison with conventional MRCP.

Biparametric 3T Magnetic Resonance Imaging for prostatic cancer detection in a biopsy-naïve patient population: a further improvement of PI-RADS v2?

OBJECTIVES: To prospectively determine the diagnostic accuracy of a biparametric 3T magnetic resonance imaging protocol (BP-MRI) for prostatic cancer detection, compared to a multiparametric MRI protocol (MP-MRI), in a biopsy naïve patient population. METHODS: Eighty-two untreated patients (mean age 65±7.6years) with clinical suspicion of prostate cancer and/or altered prostate-specific antigen (PSA) levels underwent a MP-MRI, including T2-weighted imaging, diffusion-weighted imaging (with the correspondent apparent diffusion coefficient maps) and dynamic contrast enhanced sequence, followed by prostate biopsy. Two radiologists reviewed both the BP-MRI and the MP-MRI protocols to establish a radiological diagnosis. Receiver operating characteristics curves were obtained to determine the diagnostic performance of the two protocols. RESULTS: The mean PSA level was 8.8±8.1ng/ml. A total of 34 prostatic tumors were identified, with a Gleason score that ranged from 3+3 to 5+4. Of these 34 tumors, 29 were located within the peripheral zone and 5 in the transitional zone. BP-MRI and MP-MRI showed a similar performance in terms of overall diagnostic accuracy, with an area under the curve of 0.91 and 0.93, respectively (p=n.s.). CONCLUSIONS: BP-MRI prostate protocol is feasible for prostatic cancer detection compared to a standard MP-MRI protocol, requiring a shorter acquisition and interpretation time, with comparable diagnostic accuracy to the conventional protocol, without the administration of gadolinium-based contrast agent.

Intra-Hepatic Spillage of Gallstones as a Late Complication of Laparoscopic Cholecystectomy: MR Imaging Findings.

BACKGROUND: Spillage of gallstones in the abdominal cavity may rarely occur during the course of laparoscopic cholecystectomy. Dropped gallstones in the peritoneal and extra-peritoneal cavity are usually asymptomatic. However, they may lead to abscess formation with an estimated incidence of about 0.3%. Common locations of the abscess are in the abdominal wall followed by the intra-abdominal cavity, usually in the sub-hepatic or retro-peritoneum inferior to the sub-hepatic space. CASE REPORT: We hereby describe an unusual case of infected spilled gallstones in the right sub-phrenic space, prospectively detected on abdominal MRI performed two years after laparoscopic cholecystectomy, in a patient with only a mild right-sided abdominal complaint. CONCLUSIONS: This case highlights the role of MRI in suggesting the right diagnosis in cases with vague or even absent symptomatology. In our case the patient's history together with high quality abdomen MRI allowed the correct diagnosis. Radiologists should be aware of this rare and late onset complication, even after many years from surgery as an incidental finding in almost asymptomatic patients.

Appearance of hepatocellular carcinoma on gadoxetic acid-enhanced hepato-biliary phase MR imaging: a systematic review.

OBJECTIVE: To perform a systematic review of the contrast behaviour of HCC on Gd-EOB-DTPA hepato-biliary phase MRI. MATERIALS AND METHODS: This review was completed in accordance with the recommendations outlined in the preferred reporting items for systematic reviews statement. In all reports, qualitative analysis of signal intensity (SI) of HCC on hepato-biliary phase was performed: the relative SI of HCC. When available, a quantitative analysis of tumour enhancement was evaluated. RESULTS: A total of 106 studies were retrieved, of which 41 met the inclusion criteria. The total number of patients was 2550, with 3132 HCC. MRI showed 3110 HCC (22 non-detected). 2692/3110 (87 %) HCC were hypointense on Gd-EOB-DTPA-enhanced hepatocyte-phase MRI, 134 (4 %) isointense; 106 (3 %) hyperintense and 178 (6 %) iso-hyperintense. In 26 articles, 1653 HCCs were classified as follows: 519 well-differentiated, 883 moderately differentiated, 251 poorly differentiated. Among well-differentiated HCC, 445 (86 %) were hypointense, 12 isointense (2 %), 9 hyperintense (2 %), 53 iso/hyperintense (10 %). Among moderately differentiated HCC, 774 (88 %) were hypointense, 8 isointense (1 %), 27 hyperintense (3 %), 74 iso/hyperintense (8 %). Among poorly differentiated HCCs, 245 (98 %) were hypointense, one isointense, one hyperintense and four iso-hyperintense (2 %). We found a Chi-square (χ (2)) equivalent to 25,082 (p < 0.001). CONCLUSION: The percentage of lesions iso/hyper/iso-hyper is the same when considering well-differentiated and moderately differentiated HCC; when considering poorly differentiated HCC, the percentage of lesions iso/hyper/iso-hyper is significantly lower. Conversely, the percentage of lesions hypointense is significantly more represented in poorly differentiated HCC compared to well-differentiated and moderately differentiated HCC.

Poly Implant Prothèse (PIP) incidence of rupture: a retrospective MR analysis in 64 patients.

AIM OF THE STUDY: The purpose of this retrospective study was to describe the magnetic resonance imaging (MRI) features of Poly Implant Prothèse (PIP) hydrogel implants in a group of 64 patients and to assess the incidence of rupture, compared to other clinical trials. MATERIAL AND METHODS: In this double-center study, we retrospectively reviewed the data sets of 64 consecutive patients (mean age, 43±9 years, age range, 27-65 years), who underwent breast MRI examinations, between January 2008 and October 2013, with suspected implant rupture on the basis of clinical assessment or after conventional imaging examination (either mammography or ultrasound). All patients had undergone breast operation with bilateral textured cohesive gel PIP implant insertion for aesthetic reasons. The mean time after operation was 8 years (range, 6-14 years). No patients reported history of direct trauma to their implants. RESULTS: At the time of clinical examination, 41 patients were asymptomatic, 16 complained of breast tenderness and 7 had clinical evidence of rupture. Normal findings were observed in 15 patients. In 26 patients there were signs of mild collapse, with associated not significant peri-capsular fluid collections and no evidence of implant rupture; in 23 patients there was suggestion of implant rupture, according to breast MRI leading to an indication for surgery. In particular, 14 patients showed intra-capsular rupture, with associated evidence of the linguine sign in all cases; the keyhole sign and the droplet signs were observed in 6 cases. In 9 patients there was evidence of extra-capsular rupture, with presence of axillary collections (siliconomas) in 7 cases and peri-prosthetic and mediastinal cavity siliconomas, in 5 cases. CONCLUSIONS: The results of this double center retrospective study, confirm the higher incidence (36%) of prosthesis rupture observed with the PIP implants, compared to other breast implants.

Endocrine function and bone disease during long-term chelation therapy with deferasirox in patients with ß-thalassemia major.

Iron overload in ß-thalassemia major (TM) typically results in iron-induced cardiomyopathy, liver disease, and endocrine complications. We examined the incidence and progression of endocrine disorders (hypothyroidism, diabetes, hypoparathyroidism, hypogonadism), growth and pubertal delay, and bone metabolism disease during long-term deferasirox chelation therapy in a real clinical practice setting. We report a multicenter retrospective cohort study of 86 transfusion-dependent patients with TM treated with once daily deferasirox for a median duration of 6.5 years, up to 10 years. No deaths or new cases of hypothyroidism or diabetes occurred. The incidence of new endocrine complications was 7% (P = 0.338, for change of prevalence from baseline to end of study) and included hypogonadism (n = 5) and hypoparathyroidism (n = 1). Among patients with hypothyroidism or diabetes at baseline, no significant change in thyroid parameters or insulin requirements were observed, respectively. Mean lumbar spine bone mineral density increased significantly (P < 0.001) and the number of patients with lumbar spine osteoporosis significantly decreased (P = 0.022) irrespective of bisphosphonate therapy, hormonal replacement therapy, and calcium or vitamin D supplementation. There were no significant differences in the number of pediatric patients below the 5th centile for height between baseline and study completion. Six pregnancies occurred successfully, and four of them were spontaneous without ovarian stimulation. This is the first study evaluating endocrine function during the newest oral chelation therapy with deferasirox. A low rate of new endocrine disorders and a stabilization of those pre-exisisting was observed in a real clinical practice setting.

MRI of hepatic epithelioid hemangioendothelioma (HEH).

PURPOSE: To investigate magnetic resonance imaging (MRI) characteristics of hepatic epithelioid hemangionendothelioma (HEH). MATERIALS AND METHODS: The study was exempted from formal Ethics Committee approval due to its retrospective and noninvasive nature. Eleven patients with histology-proven HEH were collected from six different institutions in a 5-year time period. In all patients a contrast-enhanced MR study was available. Two experienced reviewers in consensus retrospectively noted potential MR findings of HEH. Reviewers separately analyzed morphological findings, tumor signal intensity, HEH contrast enhancement pattern, and tumor appearance on hepatobiliary phase and diffusion-weighted imaging (DWI). The frequency of various findings was calculated. RESULTS: The most frequent presentation was a peripheral distribution of the lesions (72.7%), target appearance on T2-weighted images (63.6%), low signal intensity on T1-weighted images (63.6%), ring or target-like enhancement at dynamic study (63.6%), and coalescence of nodules and capsular retraction (45.4%). Lack of hepatobiliary enhancement (5/8 patients) or "entrapment" hepatobiliary enhancement (3/8 patients) as well as target appearance at DWI (5/6 patients) was also observed in our series. CONCLUSION: Although quite variable imaging appearances were seen, a target appearance on the T2-weighted image, ring or target enhancement at dynamic study, lack of enhancement or "entrapment" at hepatobiliary phase, and target appearance on DWI are frequent findings of HEH.

Diffusion-weighted magnetic resonance imaging in the prediction and assessment of chemotherapy outcome in liver metastases.

PURPOSE: This study assessed the capability of magnetic resonance (MR) diffusion-weighted imaging (DwI) with measurement of apparent diffusion coefficient (ADC) in both predicting and evaluating the response to chemotherapy (CHT) of liver metastases by itself and along with preliminary dimensional assessment. METHODS AND MATERIALS: Patients affected by liver metastases from cancers of the digestive tract and breast were prospectively enrolled and underwent computed tomography and MR-DwI before CHT (time 0) and 20-25 days after the beginning of the second cycle (time 3). Moreover, MR-DwI was performed 10-15 (time 1) and 20-25 days (time 2) after the beginning of the first cycle. Maximum diameter and mean ADC value (×10(-3) mm(2)/s) of metastases were evaluated. Lesions were classified as progressive disease (PD), stable disease (SD) or partial response (PR) according to dimensional changes between time 0 and time 3, following RECIST 1.1 indications. Clinically, PD lesions were defined as nonresponding (NR), and SD and PR lesions as responding (R). Analysis of variance and ROC analyses were performed (significance at p < 0.05). RESULTS: Eighty-six metastases (33 patients) were classified as follows: 15 PD, 39 SD and 32 PR without significant differences in mean ADC values among the groups before CHT and at all corresponding times. The mean ADC values of SD and PR groups at times 1 (respectively 1.66 ± 0.36 and 1.59 ± 0.23), 2 (1.72 ± 0.42 and 1.68 ± 0.37) and 3 (1.86 ± 0.44 and 1.73 ± 0.39) were significantly higher than the corresponding values at time 0 (1.50 ± 0.30 and 1.39 ± 0.33). An accurate cutoff value of ADC increase or diameter decrease for the early identification of R or NR lesions was not found. CONCLUSION: The pretreatment ADC value of a liver metastasis does not seem useful in predicting the CHT outcome. A trend towards early ADC increase, alone or occurring with dimensional decrease, may be a good indicator of a responding lesion.

Value of MRI in three patients with major vascular injuries after laparoscopic cholecystectomy.

The aim of this study was to describe three cases of major vascular injuries after laparoscopic cholecystectomy depicted on magnetic resonance (MR) examination. Three female patients (mean age, 32 years; range, 22-39 years) were studied with clinical suspicion of bilio-vascular injuries after laparoscopic cholecystectomy. All MR examinations were performed within 24 h after the laparoscopic procedure. MR imaging was evaluated for major vascular injuries involving the arterial and portal venous system, for bile duct discontinuity, presence or absence of biliary dilation, stricture, excision injury, free fluid and collections. In the first patient, a type-IV Bismuth injury with associated intrahepatic bile ducts dilation was observed. Contrast-enhanced MR revealed lack of enhancement in the right hepatic lobe due to occlusion of the right hepatic artery and the right portal branch. This patient underwent right hepatectomy with hepatico-jejunostomy. In the other two cases, no visualization of the right hepatic artery and the right portal branch was observed on MR angiography. In the first case, the patient underwent right hepatectomy; in the second case, because of stable liver condition, the patient was managed conservatively. MR imaging combined with MR angiography and MR cholangiography can be performed emergently in patients with suspicion of bilio-vascular injury after laparoscopic cholecystectomy allowing the simultaneous evaluation of the biliary tree and the hepatic vascular supply that is essential for adequate treatment planning.