Prostate MRI for the detection of clinically significant prostate cancer: Update and future directions.

PURPOSE OF REVIEW: In recent decades, there has been an increasing role for magnetic resonance imaging (MRI) in the detection of clinically significant prostate cancer (csPC). The purpose of this review is to provide an update and outline future directions for the role of MRI in the detection of csPC. RECENT FINDINGS: In diagnosing clinically significant prostate cancer pre-biopsy, advances include our understanding of MRI-targeted biopsy, the role of biparametric MRI (non-contrast) and changing indications, for example the role of MRI in screening for prostate cancer. Furthermore, the role of MRI in identifying csPC is maturing, with emphasis on standardization of MRI reporting in active surveillance (PRECISE), clinical staging (EPE grading, MET-RADS-P) and recurrent disease (PI-RR, PI-FAB). Future directions of prostate MRI in detecting csPC include quality improvement, artificial intelligence and radiomics, positron emission tomography (PET)/MRI and MRI-directed therapy. SUMMARY: The utility of MRI in detecting csPC has been demonstrated in many clinical scenarios, initially from simply diagnosing csPC pre-biopsy, now to screening, active surveillance, clinical staging, and detection of recurrent disease. Continued efforts should be undertaken not only to emphasize the reporting of prostate MRI quality, but to standardize reporting according to the appropriate clinical setting.

Prospective comparison of restriction spectrum imaging and non-invasive biomarkers to predict upgrading on active surveillance prostate biopsy.

BACKGROUND: Protocol-based active surveillance (AS) biopsies have led to poor compliance. To move to risk-based protocols, more accurate imaging biomarkers are needed to predict upgrading on AS prostate biopsy. We compared restriction spectrum imaging (RSI-MRI) generated signal maps as a biomarker to other available non-invasive biomarkers to predict upgrading or reclassification on an AS biopsy. METHODS: We prospectively enrolled men on prostate cancer AS undergoing repeat biopsy from January 2016 to June 2019 to obtain an MRI and biomarkers to predict upgrading. Subjects underwent a prostate multiparametric MRI and a short duration, diffusion-weighted enhanced MRI called RSI to generate a restricted signal map along with evaluation of 30 biomarkers (14 clinico-epidemiologic features, 9 molecular biomarkers, and 7 radiologic-associated features). Our primary outcome was upgrading or reclassification on subsequent AS prostate biopsy. Statistical analysis included operating characteristic improvement using AUROC and AUPRC. RESULTS: The individual biomarker with the highest area under the receiver operator characteristic curve (AUC) was RSI-MRI (AUC = 0.84; 95% CI: 0.71-0.96). The best non-imaging biomarker was prostate volume-corrected Prostate Health Index density (PHI, AUC = 0.68; 95% CI: 0.53-0.82). Non-imaging biomarkers had a negligible effect on predicting upgrading at the next biopsy but did improve predictions of overall time to progression in AS. CONCLUSIONS: RSI-MRI, PIRADS, and PHI could improve the predictive ability to detect upgrading in AS. The strongest predictor of clinically significant prostate cancer on AS biopsy was RSI-MRI signal output.

Restriction Spectrum Imaging-Magnetic Resonance Imaging to Improve Prostate Cancer Imaging in Men on Active Surveillance.

PURPOSE: Restriction spectrum imaging-magnetic resonance imaging is a short duration enhanced diffusion-weighted technique that seeks to standardize sequences and predict upgrading. We test this technology for active surveillance biopsies. Our objective is to investigate the utility of restriction spectrum imaging-magnetic resonance imaging to improve upgrading detection in a prostate cancer active surveillance cohort. MATERIALS AND METHODS: We prospectively enrolled men on active surveillance undergoing repeat biopsy from January 2016 to June 2019. Subjects underwent prostate multiparametric magnetic resonance imaging and restriction spectrum imaging-magnetic resonance imaging reviewed by a urological radiologist for PI-RADS® scored lesions, followed by magnetic resonance imaging-guided prostate biopsy by a urologist. Restriction spectrum imaging-magnetic resonance imaging analysis with proprietary research software (CorTechs Labs, San Diego, California) generated a restricted signal map. We compared the restricted signal map and apparent diffusion coefficient values using T-test, ANOVA, and logistic regression analyses for prediction of upgrading. RESULTS: Of 123 enrolled men we identified 74 restriction spectrum imaging-magnetic resonance imaging regions of interest (targeted lesions) in 110 subjects, with 105 subjects completing biopsy. The restricted signal map was significant per PI-RADS score for true-positive lesion detection (mean difference 28, SD 0.7, p=0.001), and better than apparent diffusion coefficient (mean difference -15, SD 55, p=0.6). Restriction spectrum imaging generated restricted signal map values >50 improved sensitivity, specificity, positive predictive value and negative predictive value (81.0%, 81.8%, 54.2% and 94.2%) over PI-RADS ≥3 (71.4%, 38.9%, 23.7% and 83.7%, respectively) for Gleason upgrading. Overall restriction spectrum imaging is able to improve the AUC of 0.70 (95% CI 0.49-0.92, p=0.03) to 0.90 (95% CI 0.82-0.98, p <0.001). CONCLUSIONS: Restriction spectrum imaging-magnetic resonance imaging enhances the standard PI-RADS system by providing a noninvasive radiological biomarker to predict upgrading in active surveillance.

Pancreatic Neuroendocrine Neoplasms: 2020 Update on Pathologic and Imaging Findings and Classification.

Pancreatic neuroendocrine neoplasms (panNENs) are heterogeneous neoplasms with neuroendocrine differentiation that show characteristic clinical, histomorphologic, and prognostic features; genetic alterations; and biologic behavior. Up to 10% of panNENs develop in patients with syndromes that predispose them to cancer, such as multiple endocrine neoplasia type 1, von Hippel-Lindau disease, tuberous sclerosis complex, neurofibromatosis type 1, and glucagon cell adenomatosis. PanNENs are classified as either functioning tumors, which manifest early because of clinical symptoms related to increased hormone production, or nonfunctioning tumors, which often manifest late because of mass effect. PanNENs are histopathologically classified as well-differentiated pancreatic neuroendocrine tumors (panNETs) or poorly differentiated pancreatic neuroendocrine carcinomas (panNECs) according to the 2010 World Health Organization (WHO) classification system. Recent advances in cytogenetics and molecular biology have shown substantial heterogeneity in panNECs, and a new tumor subtype, well-differentiated, high-grade panNET, has been introduced. High-grade panNETs and panNECs are two distinct entities with different pathogenesis, clinical features, imaging findings, treatment options, and prognoses. The 2017 WHO classification system and the eighth edition of the American Joint Committee on Cancer staging system include substantial changes. Multidetector CT, MRI, and endoscopic US help in anatomic localization of the primary tumor, local-regional spread, and metastases. Somatostatin receptor scintigraphy and fluorine 18-fluorodeoxyglucose PET/CT are helpful for functional and metabolic assessment. Knowledge of recent updates in the pathogenesis, classification, and staging of panNENs and familiarity with their imaging findings allow optimal patient treatment. ©RSNA, 2020.

Inflammation appears as high Prostate Imaging-Reporting and Data System scores on prostate magnetic resonance imaging (MRI) leading to false positive MRI fusion biopsy.

Purpose: To investigate if inflammation as a potential cause of false-positive lesions from recent UroNav magnetic resonance imaging (MRI) fusion prostate biopsy patients. Materials and Methods: We retrospectively identified 43 men with 61 MRI lesions noted on prostate MRI before MRI ultrasound-guided fusion prostate biopsy. Men underwent MRI with 3T Siemens TIM Trio MRI system (Siemens AG, Germany), and lesions were identified and marked in DynaCAD system (Invivo Corporation, USA) with subsequent biopsy with MRI fusion with UroNav. We obtained targeted and standard 12-core needle biopsies. We retrospectively reviewed pathology reports for inflammation. Results: We noted a total of 43 (70.5%) false-positive lesions with 28 having no cancer on any cores, and 15 lesions with cancer noted on systematic biopsy but not in the target region. Of the men with cancer, 6 of the false positive lesions had inflammation in the location of the targeted region of interest (40.0%, 6/15). However, when we examine the 21/28 lesions with an identified lesion on MRI with no cancer in all cores, 54.5% had inflammation on prostate biopsy pathology (12/22, p=0.024). We noted the highest proportion of inflammation. Conclusions: Inflammation can confound the interpretation of MRI by mimicking prostate cancer. We suggested focused efforts to differentiate inflammation and cancer on prostate MRI.

Multimodality imaging of adult gastric emergencies: A pictorial review.

Acute gastric emergencies require urgent surgical or nonsurgical intervention because they are associated with high morbidity and mortality. Imaging plays an important role in diagnosis since the clinical symptoms are often nonspecific and radiologist may be the first one to suggest a diagnosis as the imaging findings are often characteristic. The purpose of this article is to provide a comprehensive review of multimodality imaging (plain radiograph, fluoroscopy, and computed tomography) of various life threatening gastric emergencies.

Multimodality Imaging Findings in Carcinoid Tumors: A Head-to-Toe Spectrum.

Carcinoid tumors are a rare biologically heterogeneous group of neuroendocrine tumors with a spectrum ranging from benign indolent to aggressive metastatic tumors. They belong to the category of amine precursor uptake and decarboxylase tumors, or apudomas. The most common sites for primary locations are the gastrointestinal and respiratory tracts; however, any organ can be involved. The clinical presentation depends on location, aggressiveness, production of biologically active amines and peptides, paraneoplastic syndromes, and tendency for metastasis. Their reported age-adjusted incidence has increased in recent years, partly due to improved detection at radiologic imaging and endoscopy. Not a ll neuroendocrine cell tumors are carcinoids. Numerous systems have been proposed regarding their nomenclature and classification. Cross-sectional and functional imaging plays an important role in diagnosis, lesion characterization, and staging. Awareness of nomenclature, classification, common sites of involvement, and imaging presentation are pivotal for making the diagnosis. Knowledge of the diverse clinical, pathologic, and radiologic spectrum of carcinoid tumors involving various organs of the body is important for diagnosis and patient management. ©RSNA, 2017.

Obstructive Acute Pancreatitis Secondary to PEG Tube Migration.

Percutaneous gastrostomy is a well-established method of providing enteral nutrition to patients incapable of oral intake, or for whom oral intake is insufficient to meet metabolic needs. In comparison to total parenteral nutrition, enteral feeding is advantageous in that it helps maintain gut mucosal integrity, which decreases the risk of bacterial translocation through the gastrointestinal tract. Complications include bleeding, aspiration, internal organ injury, perforation, periostomal leaks, tube dislodgement, and occlusion. Acute pancreatitis secondary to percutaneous gastrostomy tube migration is rare. We present a patient with acute obstructive pancreatitis secondary to percutaneous gastrostomy tube migration.

Abdominal manifestations of histiocytic disorders in adults: imaging perspective.

Histiocytic disorders (HDs) are a diverse group of diseases characterized by pathologic infiltration of normal tissues by cells of the mononuclear phagocyte system. The spectrum of these diseases ranges from treatable infectious diseases to rapidly progressive, life-threatening conditions. Although they are rare and difficult diagnoses, HDs can be diagnosed with the help of clinical and laboratory analyses, imaging features and tissue biopsy. The clinicopathology and imaging spectrum of select entities belonging to this disorder are presented in this review.

Cardiopulmonary and Gastrointestinal Manifestations of Eosinophil- associated Diseases and Idiopathic Hypereosinophilic Syndromes: Multimodality Imaging Approach.

Eosinophil-associated diseases (EADs) are a diverse group of disorders characterized by an increase in circulating or tissue eosinophils. Cardiopulmonary and gastrointestinal system involvement can be due to primary EAD with no known cause or can be secondary to known systemic disease. The cardiopulmonary spectrum of EADs comprises simple pulmonary eosinophilia, acute eosinophilic pneumonia, chronic eosinophilic pneumonia, Churg-Strauss syndrome, allergic bronchopulmonary aspergillosis, bronchocentric granulomatosis, parasitic infections, and idiopathic hypereosinophilic syndrome. Eosinophilic gastrointestinal disorders include eosinophilic esophagitis, eosinophilic gastroenteritis, and eosinophilic colitis. Diagnosis is often challenging and requires a combination of clinical and imaging features along with laboratory findings. The absolute eosinophil count in peripheral blood and the percentage of eosinophils in bronchoalveolar lavage fluid are crucial in evaluation of various eosinophilic lung diseases. Although chest radiography is the initial imaging modality used in suspected cases of pulmonary EAD, multidetector computed tomography may demonstrate more characteristic pulmonary patterns, nodules, and subtle parenchymal abnormalities. Barium esophagography is used to assess mucosal abnormalities and the length and diameter of esophageal strictures. Magnetic resonance imaging is superior in providing valuable information in select patients, especially in evaluation of cardiac and gastrointestinal system involvement. Many patients require a multimodality imaging approach to enable diagnosis, guide treatment, and assess treatment response. Knowledge of the clinical features and imaging findings of the spectrum of EADs involving the lungs, heart, and gastrointestinal tract permits optimal patient care.

Imaging of Rare Primary Malignant Hepatic Tumors in Adults With Histopathological Correlation.

Hepatocellular carcinoma and cholangiocarcinoma are the most common primary liver malignancies in adults (comprising >85%); however, liver is also host to some unusual primary malignant tumors. Some of these tumors show distinct demographic, clinicopathologic, and imaging features. Imaging features of these uncommon primary malignant liver tumors are presented with an attempt to correlate them with histopathology.

Spectrum of multidetector computed tomography/magnetic resonance imaging findings in intrahepatic vascular shunts: classification, characterization, and management.

With the increasing use of multidetector computed tomography and dynamic magnetic resonance imaging in evaluation of liver pathologies, a variety of vascular shunts are detected in the liver. These shunts can be related to tumors or they can be nonneoplastic. Identification of these shunts can help in diagnosing an underlying condition. We classify and describe a wide spectrum of intrahepatic vascular shunts with their key imaging features. After reviewing this article, the reader should have improved ability to detect and characterize intrahepatic vascular shunts, which will help in diagnosing an underlying condition and facilitate optimal patient care.

Abdominal manifestations of extraosseous myeloma: cross-sectional imaging spectrum.

Extraosseous myeloma, defined as the myelomatous involvement outside the skeleton system, is rare and often associated with advanced multiple myeloma. There has been a recent increase in the clinicoradiological incidence of this entity, possibly secondary to increased survival of patients and frequent use of imaging. This has led to the development of new clinical staging guidelines for multiple myeloma, which include the use of imaging modalities positron emission tomography/computed tomography and magnetic resonance imaging for accurate detection and optimal management. The aims of this review were to discuss the significance of identification of extraosseous disease, to describe the spectrum and common sites of extraosseous involvement in the abdomen, and to review the imaging findings of extraosseous myeloma in the abdomen.

Benign non-cystic scrotal tumors and pseudotumors.

There is a wide spectrum of benign, non-cystic scrotal lesions that show characteristic histo-morphology and natural history. While sonography is the preferred modality for the diagnosis of both testicular and extratesticular masses, MRI is used as a problem-solving modality when sonographic findings are inconclusive. This article reviews the cross-sectional imaging features of benign, non-cystic, intra- and extratesticular lesions. Definitive diagnosis of benign scrotal lesions may lead to conservative management including testicular preserving surgery.

Wunderlich syndrome: cross-sectional imaging review.

Wunderlich syndrome (WS) is a rare condition characterized by acute onset of spontaneous, nontraumatic renal hemorrhage into the subcapsular and perirenal spaces. Wunderlich syndrome is classically characterized by the Lenk's triad: acute flank pain, flank mass, and hypovolemic shock. However, the clinical manifestations can be varied and nonspecific. A wide spectrum of neoplastic and nonneoplastic renal pathologies may result in WS. Renal neoplasms are the most common cause for WS, with angiomyolipoma being the most common benign neoplasm, whereas renal cell carcinoma is the most common malignant neoplasm. Other causative conditions of WS include vascular causes (vasculitis [polyarteritis nodosa being the most common cause], renal artery aneurysms, arteriovenous malformations and fistulas, and venous thrombosis), cystic renal diseases, renal infections, calculus disease, nephritis, and coagulation disorders. Cross-sectional imaging findings help in the detection of the subcapsular and/or perinephric hemorrhage and may identify underlying etiology. Renal angiography not only helps in diagnosis of the underlying cause in select cases but also allows control of active bleeding, which can avoid unnecessary emergent radical surgery.

Emphysematous cholecystitis: Imaging findings in nine patients.

OBJECTIVE: Emphysematous cholecystitis is a severe form of acute cholecystitis and can be rapidly fatal. We present the imaging features of nine patients with proven emphysematous cholecystitis.

Tumors and pseudotumors of the secondary müllerian system: review with emphasis on cross-sectional imaging findings.

OBJECTIVE: Microscopic structures lined by müllerian epithelium are frequently seen outside the uterus and fallopian tubes and are termed "müllerian rests" or "secondary müllerian system." Varied entities ranging from benign endosalpingosis to highly malignant ovarian tumors are thought to be derived from the secondary müllerian system. Cross-sectional imaging findings of diseases and disorders of the secondary müllerian system are presented here. CONCLUSION: Familiarity with a wide spectrum of diseases and disorders of the secondary müllerian system allows accurate diagnosis and management.

Nonalcoholic, nonbiliary pancreatitis: cross-sectional imaging spectrum.

OBJECTIVE: The purpose of this review is to describe the epidemiologic, etiopathogenetic, clinical, and imaging characteristics of various nonalcoholic, nonbiliary pancreatitis syndromes. CONCLUSION: The spectrum of nonalcoholic, nonbiliary pancreatitis includes autoimmune pancreatitis, groove pancreatitis, hereditary pancreatitis, tropical pancreatitis, tuberculous pancreatitis, and metabolic pancreatitis. Advances in genetics and molecular pathology have shed new light on the etiopathogenesis and course of these syndromes. Accurate diagnosis aided by imaging findings allows optimal management.

Taxonomy and imaging spectrum of small bowel obstruction after Roux-en-Y gastric bypass surgery.

OBJECTIVE: For most patients with morbid obesity, bariatric surgery is the only effective method to achieve sustainable weight loss. Small bowel obstruction (SBO) after bariatric surgery is a major complication that affects postoperative course and management. Knowledge of the types of and imaging findings for SBO is essential to prompt diagnosis. CONCLUSION: We discuss different types of SBO and a taxonomic schemata of bowel obstruction (ABC classification) and present a review of imaging findings that facilitates optimal patient management.