MRI-Based Radiomics in Bladder Cancer: A Systematic Review and Radiomics Quality Score Assessment.

(1): Background: With the recent introduction of vesical imaging reporting and data system (VI-RADS), magnetic resonance imaging (MRI) has become the main imaging method used for the preoperative local staging of bladder cancer (BCa). However, the VI-RADS score is subject to interobserver variability and cannot provide information about tumor cellularity. These limitations may be overcome by using a quantitative approach, such as the new emerging domain of radiomics. (2) Aim: To systematically review published studies on the use of MRI-based radiomics in bladder cancer. (3) Materials and Methods: We performed literature research using the PubMed MEDLINE, Scopus, and Web of Science databases using PRISMA principles. A total of 1092 papers that addressed the use of radiomics for BC staging, grading, and treatment response were retrieved using the keywords "bladder cancer", "magnetic resonance imaging", "radiomics", and "textural analysis". (4) Results: 26 papers met the eligibility criteria and were included in the final review. The principal applications of radiomics were preoperative tumor staging (n = 13), preoperative prediction of tumor grade or molecular correlates (n = 9), and prediction of prognosis/response to neoadjuvant therapy (n = 4). Most of the developed radiomics models included second-order features mainly derived from filtered images. These models were validated in 16 studies. The average radiomics quality score was 11.7, ranging between 8.33% and 52.77%. (5) Conclusions: MRI-based radiomics holds promise as a quantitative imaging biomarker of BCa characterization and prognosis. However, there is still need for improving the standardization of image preprocessing, feature extraction, and external validation before applying radiomics models in the clinical setting.

Overlap syndrome of autoimmune hepatitis and primary biliary cholangitis complicated with atypical hepatocellular carcinoma: a case report.

BACKGROUND: Hepatocellular carcinoma (HCC) is a primary tumor of the liver. The majority of HCCs are associated most frequently with chronic B or C viral hepatitis, alcohol intake or aflatoxin exposure. Cirrhosis is a strong risk factor associated with HCC. The causes of liver cirrhosis are chronic viral hepatitis, alcohol intake, metabolic diseases (NAFLD), hemocromathosis, alfa 1 antitrypsisn deficiency. All aetiologic forms of cirrhosis are at risk to be complicated by HCC development, but the risk is higher for patients diagnosed with chronic viral hepatitis. Comparing to the above-mentioned causes, PBC and AIH are less associated with the risk of HCC development. A 71-year old Caucasian female previously diagnosed with overlap syndrome (AIH type 1 and PBC-ANA, SMA and AMA antibodies positive), liver cirrhosis, a nodule in the VI/VIIth hepatic segment, systemic sclerosis sine scleroderma, Hashimoto's thyroiditis, antiphospholipid syndrome, gastric antral vascular ectasia (GAVE) (with 2 previous sessions of argon plasma coagulation), cholecystectomy, arterial hypertension and nephro-angiosclerosis presented to the 2nd Department of Internal Medicine in Cluj-Napoca for a follow-up. The patient was following treatment with UDCA (Ursodeoxycholic acid), azathioprine, Plaquenil, calcium channel blockers, angiotensin-converting-enzyme inhibitor, calcium and vitamin D supplementation. The abdominal ultrasound showed a subcapsular hypoechoic nodule with a diameter of 29 mm (at the moment of the diagnosis the diameter was 9/10 mm) in the VI/VIIth hepatic segment. The contrast-enhanced ultrasound (CEUS) characterised the nodule as specific for hepatocellular carcinoma (LI-RADS 5). On MRI with gadoxetate disodium the nodule was hypovascular, non-specific, being classified as LI-RADS 3. An atypical resection of the VIIth hepatic segment was performed and the histohistological examination and imunohistochemistry (Hep Par-a positive, Glypican3 positive, CD34 positive) revealed a moderately differentiated hepatocellular carcinoma (G2), pT2 N0 M0 L0 V1 R0. CONCLUSION: Autoimmune hepatitis, PBC and the overlap syndrome are less associated with the development of liver cirrhosis and HCC than other chronic liver diseases, especially if other risk factors are not associated. This case highlights the importance of a proper surveillance of cirrhotic patients every 6 months including abdominal ultrasound and AFP levels is crucial for an early diagnosis of a HCC.

A Light, 3D UNet-based Architecture for Fully Automatic Segmentation of Prostate Lesions from T2-MRI Images.

INTRODUCTION: Prostate magnetic resonance imaging (MRI) has been recently integrated into the pathway of diagnosis of prostate cancer (PCa). However, the lack of an optimal contrast-to-noise ratio hinders automatic recognition of suspicious lesions, thus developing a solution for proper delimitation of the tumour and its separation from the healthy parenchyma, which is of primordial importance. METHOD: As a solution to this unmet medical need, we aimed to develop a decision support system based on artificial intelligence, which automatically segments the prostate and any suspect area from the 3D MRI images. We assessed retrospective data from all patients diagnosed with PCa by MRI-US fusion prostate biopsy, who underwent prostate MRI in our department due to a clinical or biochemical suspicion of PCa (n=33). All examinations were performed using a 1.5 Tesla MRI scanner. All images were reviewed by two radiologists, who performed manual segmentation of the prostate and all lesions. A total of 145 augmented datasets were generated. The performance of our fully automated end-to-end segmentation model based on a 3D UNet architecture and trained in two learning scenarios (on 14 or 28 patient datasets) was evaluated by two loss functions. RESULTS: Our model had an accuracy of over 90% for automatic segmentation of prostate and PCa nodules, as compared to manual segmentation. We have shown low complexity networks, UNet architecture with less than five layers, as feasible and to show good performance for automatic 3D MRI image segmentation. A larger training dataset could further improve the results. CONCLUSION: Therefore, herein, we propose a less complex network, a slim 3D UNet with superior performance, being faster than the original five-layer UNet architecture.

Fully automated bladder tumor segmentation from T2 MRI images using 3D U-Net algorithm.

Introduction: Bladder magnetic resonance imaging (MRI) has been recently integrated in the diagnosis pathway of bladder cancer. However, automatic recognition of suspicious lesions is still challenging. Thus, development of a solution for proper delimitation of the tumor and its separation from the healthy tissue is of primordial importance. As a solution to this unmet medical need, we aimed to develop an artificial intelligence-based decision support system, which automatically segments the bladder wall and the tumor as well as any suspect area from the 3D MRI images. Materials: We retrospectively assessed all patients diagnosed with bladder cancer, who underwent MRI at our department (n=33). All examinations were performed using a 1.5 Tesla MRI scanner. All images were reviewed by two radiologists, who performed manual segmentation of the bladder wall and all lesions. First, the performance of our fully automated end-to-end segmentation model based on a 3D U-Net architecture (by considering various depths of 4, 5 or 6 blocks) trained in two data augmentation scenarios (on 5 and 10 augmentation datasets per original data, respectively) was tested. Second, two learning setups were analyzed by training the segmentation algorithm with 7 and 14 MRI original volumes, respectively. Results: We obtained a Dice-based performance over 0.878 for automatic segmentation of bladder wall and tumors, as compared to manual segmentation. A larger training dataset using 10 augmentations for 7 patients could further improve the results of the U-Net-5 model (0.902 Dice coefficient at image level). This model performed best in terms of automated segmentation of bladder, as compared to U-Net-4 and U-Net-6. However, in this case increased time for learning was needed as compared to U-Net-4. We observed that an extended dataset for training led to significantly improved segmentation of the bladder wall, but not of the tumor. Conclusion: We developed an intelligent system for bladder tumors automated diagnostic, that uses a deep learning model to segment both the bladder wall and the tumor. As a conclusion, low complexity networks, with less than five-layers U-Net architecture are feasible and show good performance for automatic 3D MRI image segmentation in patients with bladder tumors.

More than Meets the Eye: Using Textural Analysis and Artificial Intelligence as Decision Support Tools in Prostate Cancer Diagnosis-A Systematic Review.

(1) Introduction: Multiparametric magnetic resonance imaging (mpMRI) is the main imagistic tool employed to assess patients suspected of harboring prostate cancer (PCa), setting the indication for targeted prostate biopsy. However, both mpMRI and targeted prostate biopsy are operator dependent. The past decade has been marked by the emerging domain of radiomics and artificial intelligence (AI), with extended application in medical diagnosis and treatment processes. (2) Aim: To present the current state of the art regarding decision support tools based on texture analysis and AI for the prediction of aggressiveness and biopsy assistance. (3) Materials and Methods: We performed literature research using PubMed MeSH, Scopus and WoS (Web of Science) databases and screened the retrieved papers using PRISMA principles. Articles that addressed PCa diagnosis and staging assisted by texture analysis and AI algorithms were included. (4) Results: 359 papers were retrieved using the keywords "prostate cancer", "MRI", "radiomics", "textural analysis", "artificial intelligence", "computer assisted diagnosis", out of which 35 were included in the final review. In total, 24 articles were presenting PCa diagnosis and prediction of aggressiveness, 7 addressed extracapsular extension assessment and 4 tackled computer-assisted targeted prostate biopsies. (5) Conclusions: The fusion of radiomics and AI has the potential of becoming an everyday tool in the process of diagnosis and staging of the prostate malignancies.

Quantitative MRI of Pancreatic Cystic Lesions: A New Diagnostic Approach.

The commonly used magnetic resonance (MRI) criteria can be insufficient for discriminating mucinous from non-mucinous pancreatic cystic lesions (PCLs). The histological differences between PCLs' fluid composition may be reflected in MRI images, but cannot be assessed by visual evaluation alone. We investigate whether additional MRI quantitative parameters such as signal intensity measurements (SIMs) and radiomics texture analysis (TA) can aid the differentiation between mucinous and non-mucinous PCLs. Fifty-nine PCLs (mucinous, n = 24; non-mucinous, n = 35) are retrospectively included. The SIMs were performed by two radiologists on T2 and diffusion-weighted images (T2WI and DWI) and apparent diffusion coefficient (ADC) maps. A total of 550 radiomic features were extracted from the T2WI and ADC maps of every lesion. The SIMs and TA features were compared between entities using univariate, receiver-operating, and multivariate analysis. The SIM analysis showed no statistically significant differences between the two groups (p = 0.69, 0.21-0.43, and 0.98 for T2, DWI, and ADC, respectively). Mucinous and non-mucinous PLCs were successfully discriminated by both T2-based (83.2-100% sensitivity and 69.3-96.2% specificity) and ADC-based (40-85% sensitivity and 60-96.67% specificity) radiomic features. SIMs cannot reliably discriminate between PCLs. Radiomics have the potential to augment the common MRI diagnosis of PLCs by providing quantitative and reproducible imaging features, but validation is required by further studies.

The added value of CEUS and ultrasound-guided biopsy in diagnosing an aggressive desmoplastic small round cell tumour of peritoneum in a young male. A case report.

Desmoplastic small round cell tumour (DSRCT) is a rare and highly aggressive mesenchymal neoplasm with poor prognosis that develops in male adolescents and young adults. We report the case of a 32-year-old male admitted with abdominal distension and ascites. An ultrasonography (US) scan showed multiple peritoneal masses with large ascites. The dominant mass had a hypervascular homogenous aspect at contrast-enhanced ultrasound with wash-out in the venous phase. Thoracoabdominal CT, performed for staging the disease, confirmed the US aspect. The US-guided percutaneous biopsy revealed DSRCT of the peritoneum. Chemotherapy was then started with minimal clinical improvement, increase in tumoral burden and death after three months. US and US-guided biopsy played an essential role in diagnosing this case. The aggressive course of the disease and seeding at paracentesis sites are the particularities of the presented case.

The Utility of ADC First-Order Histogram Features for the Prediction of Metachronous Metastases in Rectal Cancer: A Preliminary Study.

This study aims the ability of first-order histogram-based features, derived from ADC maps, to predict the occurrence of metachronous metastases (MM) in rectal cancer. A total of 52 patients with pathologically confirmed rectal adenocarcinoma were retrospectively enrolled and divided into two groups: patients who developed metachronous metastases (n = 15) and patients without metachronous metastases (n = 37). We extracted 17 first-order (FO) histogram-based features from the pretreatment ADC maps. Student's t-test and Mann-Whitney U test were used for the association between each FO feature and presence of MM. Statistically significant features were combined into a model, using the binary regression logistic method. The receiver operating curve analysis was used to determine the diagnostic performance of the individual parameters and combined model. There were significant differences in ADC 90th percentile, interquartile range, entropy, uniformity, variance, mean absolute deviation, and robust mean absolute deviation in patients with MM, as compared to those without MM (p values between 0.002-0.01). The best diagnostic was achieved by the 90th percentile and uniformity, yielding an AUC of 0.74 [95% CI: 0.60-0.8]). The combined model reached an AUC of 0.8 [95% CI: 0.66-0.90]. Our observations point out that ADC first-order features may be useful for predicting metachronous metastases in rectal cancer.

Analyzing the learning curves of a novice and an experienced urologist for transrectal magnetic resonance imaging-ultrasound fusion prostate biopsy.

BACKGROUND: The aim of the current study was to evaluate and compare the learning curves of transrectal magnetic resonance imaging-ultrasound fusion biopsy for two urologists with different backgrounds (Operator 1: experienced, self-trained and Operator 2: novice, trained by a mentor/MRI reading courses). METHODS: A cohort of 400 patients who underwent fusion prostate biopsy in our department was analyzed. The learning curves were assessed in terms of overall and clinically significant prostate cancer (PCa) detection rates, percentage of positive biopsy cores/targeted and the percentage of PCa tissue on positive targeted cores. RESULTS: Increasing trends were observed for both urologists in terms of all biopsy outcomes during the study time. For the novice urologist, a significant increase was observed for overall PCa detection rate, but not for clinically significant disease (25.44%, P=0.04/15%, P=0.145). Operator 1 showed an increasing diagnosis yield of clinically significant disease up to 104 cases. Similar cancer detection rates were observed when comparing the first and last biopsies performed by both operators. Multivariate analysis adjusted for age, PSA, prostate volume, lesion diameter and PIRADS score showed an increase of PCa detection with 51% for every 52 biopsies performed (P=0.022). CONCLUSIONS: When starting with magnetic resonance imaging-ultrasound fusion prostate biopsy, mentoring and prostate magnetic resonance imaging reading training allow a novice urologist to demonstrate a good initial PCa detection rate. After about 52 cases, he reached a stable PCa and clinically significant PCa detection rate, that was similar to that of an experienced urologist.

WFUMB Position Paper-Incidental Findings, How to Manage: Spleen.

The World Federation for Ultrasound in Medicine and Biology (WFUMB) is addressing the issue of incidental findings (IFs) with a series of publications entitled "Incidental Imaging Findings-The Role of Medical Ultrasound." IFs are less commonly encountered in the spleen than in many other abdominal organs but remain a frequent dilemma in clinical practice. A histological diagnosis is rarely necessary for patient management. Many IFs, such as secondary spleens and splenic cysts, are harmless and do not require any further investigation. The diagnosis of many other focal splenic lesions is, however, often problematic. The following overview is intended to illustrate a variety of incidentally detected spleen pathologies such as size variants, shape variants, secondary spleens, focal splenic lesions and splenic calcifications. It should aid the examiner in establishing the diagnosis. Moreover, it should help the ultrasound practitioner decide which pathologies need no further investigation, those requiring interval imaging and cases in which immediate further diagnostic procedures are required.

Ultrasound or Sectional Imaging Techniques as Screening Tools for Hepatocellular Carcinoma: Fall Forward or Move Forward?

Hepatocellular carcinoma (HCC) is probably the epitome of a screening target, with a well-defined high-risk population, accessible screening methods, and multiple curative-intent treatments available for early disease. Per major societies guideline consensus, biannual ultrasound (US) surveillance of the at-risk patients is the current standard of care worldwide. Yet, despite its documented success in the past decades, this standard is far from perfect. While the whole community is working to further tighten the knots, a worrying number of cases still slip through this safety net. Consequently, these patients lose their chance to a curative solution which leads to a high disease burden with disproportionate mortality. While US will probably remain the fundamental staple in the screening strategy, key questions are seeking better answers. How can its caveats be addressed, and the technique be improved? When are further steps needed? How to increase accuracy without giving up on accessibility? This narrative review discusses the place of US surveillance in the bigger HCC picture, trying to navigate through its strengths and limits based on the most recent available evidence.

Pre-Treatment T2-WI Based Radiomics Features for Prediction of Locally Advanced Rectal Cancer Non-Response to Neoadjuvant Chemoradiotherapy: A Preliminary Study.

Locally advanced rectal cancer (LARC) response to neoadjuvant chemoradiotherapy (nCRT) is very heterogeneous and up to 30% of patients are considered non-responders, presenting no tumor regression after nCRT. This study aimed to determine the ability of pre-treatment T2-weighted based radiomics features to predict LARC non-responders. A total of 67 LARC patients who underwent a pre-treatment MRI followed by nCRT and total mesorectal excision were assigned into training (n = 44) and validation (n = 23) groups. In both datasets, the patients were categorized according to the Ryan tumor regression grade (TRG) system into non-responders (TRG = 3) and responders (TRG 1 and 2). We extracted 960 radiomic features/patient from pre-treatment T2-weighted images. After a three-step feature selection process, including LASSO regression analysis, we built a radiomics score with seven radiomics features. This score was significantly higher among non-responders in both training and validation sets (p < 0.001 and p = 0.03) and it showed good predictive performance for LARC non-response, achieving an area under the curve (AUC) = 0.94 (95% CI: 0.82-0.99) in the training set and AUC = 0.80 (95% CI: 0.58-0.94) in the validation group. The multivariate analysis identified the radiomics score as an independent predictor for the tumor non-response (OR = 6.52, 95% CI: 1.87-22.72). Our results indicate that MRI radiomics features could be considered as potential imaging biomarkers for early prediction of LARC non-response to neoadjuvant treatment.

LI-RADS ancillary features on contrast-enhanced ultrasonography.

The Liver Imaging Reporting and Data System (LI-RADS) was created to standardize liver imaging in patients at high risk for hepatocellular carcinoma (HCC), and it uses a diagnostic algorithm to assign categories that reflect the relative probability of HCC, non-HCC malignancies, or benign focal liver lesions. In addition to major imaging features, ancillary features (AFs) are used by radiologists to refine the categorization of liver nodules. In the present document, we discuss and explain the application of AFs currently defined within the LI-RADS guidelines. We also explore possible additional AFs visible on contrast-enhanced ultrasonography (CEUS). Finally, we summarize the management of CEUS LI-RADS features, including the role of current and potential future AFs.

Indications for abdominal imaging: When and what to choose?

Imaging has a very important role in evaluating abdominal pathology. A good knowledge of indications is of crucial importance in the management of the patient with abdominal pathology. Ultrasound, which on its own can lead to an accurate diagnosis, plays a pivotal role in the management of abdominal pathology. The use of ultrasound contrast agents has significantly improved ultrasound diagnostic capacities in both hepatic and non-hepatic pathology. The use of computed tomography should be limited due to the potential harmful side effects of ionizing radiation, but it has established roles in evaluating severe abdominal traumatic and non-traumatic emergencies as well as in staging oncologic patients. Magnetic resonance imaging has very limited utility in abdominal emergencies due to difficulty of accessing the scanner and the long duration of the examination compared to computed tomography or ultrasound. However, magnetic resonance imaging has well-established clinical roles particularly for evaluating diffuse or focal hepatic pathology, benign and malignant bile duct pathology, pancreatic tumors, inflammatory bowel disease and rectal tumors. The aims of the following paper are to familiarize the clinician with the indications for imaging in abdominal pathology, to guide the clinician and radiologist in choosing the correct technique for a particular clinical situation, to prevent the overuse of imaging techniques and to prevent misdiagnosis of disease and incorrect therapy resulting from inappropriate imaging.Imaging has a very important role in evaluating abdominal pathology. A good knowledge of indications is of crucial importance in the management of the patient with abdominal pathology. Ultrasound, which on its own can lead to an accurate diagnosis, plays a pivotal role in the management of abdominal pathology. The use of ultrasound contrast agents has significantly improved ultrasound diagnostic capacities in both hepatic and non-hepatic pathology. The use of computed tomography should be limited due to the potential harmful side effects of ionizing radiation, but it has established roles in evaluating severe abdominal traumatic and non-traumatic emergencies as well as in staging oncologic patients. Magnetic resonance imaging has very limited utility in abdominal emergencies due to difficulty of accessing the scanner and the long duration of the examination compared to computed tomography or ultrasound. However, magnetic resonance imaging has well-established clinical roles particularly for evaluating diffuse or focal hepatic pathology, benign and malignant bile duct pathology, pancreatic tumors, inflammatory bowel disease and rectal tumors. The aims of the following paper are to familiarize the clinician with the indications for imaging in abdominal pathology, to guide the clinician and radiologist in choosing the correct technique for a particular clinical situation, to prevent the overuse of imaging techniques and to prevent misdiagnosis of disease and incorrect therapy resulting from inappropriate imaging.

Systematic sampling during MRI-US fusion prostate biopsy can overcome errors of targeting-prospective single center experience after 300 cases in first biopsy setting.

BACKGROUND: Multiparametric magnetic resonance imaging (mpMRI) and targeted biopsy have become an integral part of the diagnosis of prostate cancer (PCa), as recommended by the European Association of Urology Guidelines. The aim of the current study was to evaluate the performance of MRI and MRI-transrectal ultrasound (TRUS) fusion prostate biopsy as first biopsy setting in a tertiary center. METHODS: A cohort of 300 patients was included in the current analysis. All patients presented with clinical or biochemical suspicion of PCa and harbored at least one suspect lesion on mpMRI. MRI-TRUS fusion prostate biopsy, followed by 12 core systematic prostate biopsy were performed by the same operator using a rigid registration system. RESULTS: The mean age of the patients was 64 years (IQR: 58-68.5 years) and the mean PSA was 6.35 ng/mL (IQR: 4.84-9.46 ng/mL). Overall cancer and csPCa diagnosis rates were 47% and 40.66%. Overall PCa/csPCa detection rates were 20.4%/11.1%, 52%/45% and 68.5%/66.7% for PI-RADS lesions 3, 4 and 5 (P<0.001/P<0.0001). Larger lesion diameter and lesion volume were associated with PCa diagnosis (P=0.006 and P=0.001, respectively). MRI-TRUS fusion biopsy missed PCa diagnosis in 37 cases (of whom 48.6% ISUP 1) in comparison with 9 patients missed by systematic biopsy (of whom 11.1% ISUP 1). In terms of csPCa, systematic biopsy missed 77.7% of the tumors located in the anterior and transitional areas. The rate of csPCa was highest when targeted biopsy was associated with systematic biopsy: 86.52% vs. 68.79% for targeted biopsy vs. 80.14% for systematic biopsy, P=0.0004. In 60.6% of cases, systematic biopsy was positive for PCa at the same site as the targeted lesion. Of these patients, eight harbored csPCa and were diagnosed exclusively on systematic biopsy. CONCLUSIONS: MRI-TRUS fusion prostate biopsy improves the diagnosis of csPCa. The main advantage of an MRI-guided approach is the diagnosis of anterior and transitional area tumors. The best results in terms of csPCa diagnosis are obtained by the combination of MRI-TRUS fusion with systematic biopsy. The systematic biopsy performed during MRI-targeted biopsy could have an important role in overcoming errors of MRI-TRUS fusion systems.

Contraindications and adverse effects in abdominal imaging.

Ultrasound (US), computed-tomography (CT) and magnetic resonance imaging (MRI) are the most frequently used imaging techniques in abdominal pathology. US plays a pivotal role in evaluating abdominal disease, sometimes being sufficient for a complete diagnosis and has virtually no contraindications. The usage of US contrast agents will add useful diagnostic information in both hepatic and non-hepatic pathology. CT has, over MRI, the advantage of being readily available. The usage of ionizing radiation is the main pitfall of CT. Allergies and contrast induced nephropathy in patients with an impaired renal function are the major risks of contrast media administration in CT. Its excellent tissue resolution makes MRI a very useful technique in abdominal pathology, the major contraindications being the presence of MRI "unsafe" implants and devices and the presence of metallic foreign bodies, particularly close to vital structures like the eyes or major vessels. Contrast administration in MRI is restricted in patients with renal insufficiency due to the risk of nephrogenic systemic fibrosis. Allergies to MRI contrast media are rare and less important compared to allergies due to CT contrast media.

Vanishing splenic cyst- visible on ultrasound but non-detected on MRI.

This paper ilustrates the imaging aspect of a rare pathology- aorto-mesenteric compression syndrome (Wilkie's disease). In this disease acute angulation of the superior mesenteric artery will lead to compression of the duodenum and of the left renal vein. Duodenal compression may lead to delayed gastric emptying and to nutcraker syndrome when left flank pain and hematuria may be present.

MRI-TRUS fusion guided prostate biopsy - initial experience and assessment of the role of contralateral lobe systematic biopsy.

AIMS: To present our initial experience and results of MRI-TRUS fusion guided prostate biopsy and assess the role of contralateral lobe systematic biopsy. MATERIAL AND METHOD: A number of 119 patients with clinical or biochemical suspicion for prostate cancer (PCa) were included. All patients harbored at least one PIRADS score ≥ 3 lesion and underwent MRI-TRUS fusion guided biopsy, as well as a concurrent systematic biopsy. The biopsy was performed by the same operator, using a rigidregistration software system. RESULTS: The mean age of the patients was 62.2 years. The mean pre-biopsy PSA was 9.15 ng/dl. The diagnosis rate of MRI-TRUS fusion guided biopsy was 47% for overall PCa and 29.4% for clinically significant (cs) PCa. A higher PIRADS score was significantly associated with the presence of overall and csPCa. MRI-TRUS fusion guided biopsy had a higher percentage of positive biopsy cores (51% vs 29%), higher likelihood of csPCa (OR 5.36, p=0.008) and upgrading (14.8%) in comparison with systematic biopsy but missed 6.7% csPCa. The contralateral lobe systematic biopsy could have been avoided without losing the PCa diagnosis all patients with PIRADS score 5, both in initial and repeat biopsy setting. Anterior and transitional lesions were more likely to be diagnosed only by targeted cores. CONCLUSION: MRI-TRUS guided prostate biopsy improves the detection of PCa, but systematic biopsy is still essential. In selected cases (PIRADS 5), contralateral lobe systematic biopsy can safely be avoided. Pre-biopsy mpMRI might reduce the number of biopsy sessions in patients with anterior and transitional lesions.

Reasons for inadequate or incomplete imaging techniques.

Even if imaging has developed considerably during the last decades there still exist several factors which limit its capacities. These factors can either limit the usage of a technique or degrade images making them difficult to interpret. Magnetic resonance imaging (MRI) has, as an absolute contraindication, the presence of metallic devices marked as "MRI unsafe" and metallic foreign bodies close to the eye or vital structures. Claustrophobia and artefacts reduce the application and performance of MRI in a significant proportion of patients. The major disadvantages of computed tomography(CT) are the exposure to ionizing radiation inducing malignancies especially in pediatric patients and the risk of contrast induced allergies and nephropathy. Ultrasound is a safe, easily available and low-cost imaging technique without significant side effects for the patient. Obesity or bloating can severely limit ultrasound capacities.This paper written by radiologists and clinicians, highlights the main reasons leading to inadequate imaging and points out solutions to avoid inaccurate diagnosis due to incomplete imaging or presence of artifacts.