Imaging of pancreatic ductal adenocarcinoma - An update for all stages of patient management.

Background: Pancreatic ductal adenocarcinoma (PDAC) is a common and lethal cancer. From diagnosis to disease staging, response to neoadjuvant therapy assessment and patient surveillance after resection, imaging plays a central role, guiding the multidisciplinary team in decision-planning. Review aims and findings: This review discusses the most up-to-date imaging recommendations, typical and atypical findings, and issues related to each step of patient management. Example cases for each relevant condition are presented, and a structured report for disease staging is suggested. Conclusion: Despite current issues in PDAC imaging at different stages of patient management, the radiologist is essential in the multidisciplinary team, as the conveyor of relevant imaging findings crucial for patient care.

Diffusion-weighted imaging for determining response to neoadjuvant therapy in pancreatic cancer: a systematic review and meta-analysis.

OBJECTIVES: To determine the role of diffusion-weighted imaging (DWI) for predicting response to neoadjuvant therapy (NAT) in pancreatic cancer. MATERIALS AND METHODS: MEDLINE, EMBASE, and Cochrane Library databases were searched for studies evaluating the performance of apparent diffusion coefficient (ADC) to assess response to NAT. Data extracted included ADC pre- and post-NAT, for predicting response as defined by imaging, histopathology, or clinical reference standards. ADC values were compared with standardized mean differences. Risk of bias was assessed using the Quality Assessment of Diagnostic Studies (QUADAS-2). RESULTS: Of 337 studies, 7 were included in the analysis (161 patients). ADC values reported for the pre- and post-NAT assessments overlapped between responders and non-responders. One study reported inability of ADC increase after NAT for distinguishing responders and non-responders. A correlation with histopathological response was reported for pre- and post-NAT ADC in 4 studies. DWI's diagnostic performance was reported to be high in three studies, with a 91.6-100% sensitivity and 62.5-94.7% specificity. Finally, heterogeneity and high risk of bias were identified across studies, affecting the domains of patient selection, index test, reference standard, and flow and timing. CONCLUSION: DWI might be useful for determining response to NAT in pancreatic cancer. However, there are still too few studies on this matter, which are also heterogeneous and at high risk for bias. Further studies with standardized procedures for data acquisition and accurate reference standards are needed. CLINICAL RELEVANCE STATEMENT: Diffusion-weighted MRI might be useful for assessing response to neoadjuvant therapy in pancreatic cancer. However, further studies with robust data are needed to provide specific recommendations for clinical practice. KEY POINTS: •The role of DWI with ADC measurements for assessing response to neoadjuvant therapy in pancreatic cancer is still unclear. •Pre- and post-neoadjuvant therapy ADC values overlap between responders and non-responders. •DWI has a reported high diagnostic performance for determining response when using histopathological or clinical reference standards; however, studies are still few and at high risk for bias.

Can We Discriminate Symptomatic Hip Patients From Asymptomatic Volunteers Based on Anatomic Predictors? A 3-Dimensional Magnetic Resonance Study on Cam, Pincer, and Spinopelvic Parameters.

BACKGROUND: Given the high prevalence of patients with hip deformities and no ongoing hip dysfunction, understanding the anatomic factors predicting the symptomatic state is critical. One such variable is how the spinopelvic parameters (SPPs) may interplay with hip anatomic factors. HYPOTHESIS/PURPOSE: SPPs and femoral- and acetabular-specific parameters may predict which patients will become symptomatic. The purpose was to determine which anatomic characteristics with specific cutoffs were associated with hip symptom development and how these parameters relate to each other. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 2. METHODS: 548 participants were designated either symptomatic patients (n = 176, scheduled for surgery with hip pain and/or functional limitation) or asymptomatic volunteers (n = 372, no pain) and underwent 3-dimensional magnetic resonance imaging. Multiple femoral (α angle, Ω angle, neck angle, torsion), acetabular (version, coverage), and spinopelvic (pelvic tilt, sacral slope [SS], pelvic incidence) parameters were measured semiautomatically. Normative values, optimal differentiating thresholds, and a logistic regression analysis were computed. RESULTS: Symptomatic patients had larger cam deformities (defined by increased Ω angle and α angle), smaller acetabular coverage, and larger pelvic incidence and SS angles compared with the asymptomatic volunteers. Discriminant receiver operating characteristic analysis confirmed that radial 2-o'clock α angle (threshold 58°-60°, sensitivity 75%-60%, specificity 80%-84%; area under the curve [AUC] = 0.831), Ω angle (threshold 43°, sensitivity 72%, specificity 70%; AUC = 0.830), acetabular inclination (threshold 6°, sensitivity 65%, specificity 70%; AUC = 0.709), and SS (threshold 44°, sensitivity 72%, specificity 75%; AUC = 0.801) ( P < .005) were the best parameters to classify participants. When parameters were entered into a logistic regression, significant positive predictors for the symptomatic patients were achieved for SS, acetabular inclination, Ω angle, and α angle at 2-o'clock, correctly classifying 85% of cases (model sensitivity 72%, specificity 91%; AUC = 0.919). CONCLUSION: Complex dynamic interplay exists between the hip and SPPs. A cam deformity, acetabular undercoverage, and increased SPP angles are predictive of a hip symptomatic state. SPPs were significant to discriminate between participants and were important in combination with other hip deformities. Symptomatic patients can be effectively differentiated from asymptomatic volunteers based on predictive anatomic factors.

Prostate Cancer: The Role of Multiparametric Magnetic Resonance Imaging.

Multiparametric magnetic resonance imaging has been increasingly used for detection, localization and staging of prostate cancer over the last years. It combines high-resolution T2 weighted-imaging and at least two functional techniques, which include dynamic contrast-enhanced magnetic resonance imaging, diffusion-weighted imaging, and magnetic resonance imaging spectroscopy. Although the combined use of a pelvic phased-array and an endorectal coil is considered the state-of-the-art for magnetic resonance imaging evaluation of prostate cancer, endorectal coil is only absolute mandatory for magnetic resonance imaging spectroscopy at 1.5 T. Sensitivity and specificity levels in cancer detection and localization have been improving with functional technique implementation, compared to T2 weighted-imaging alone. It has been particularly useful to evaluate patients with abnormal PSA and negative biopsy. Moreover, the information added by the functional techniques may correlate to cancer aggressiveness and therefore be useful to select patients for focal radiotherapy, prostate sparing surgery, focal ablative therapy and active surveillance. However, more studies are needed to compare the functional techniques and understand the advantages and disadvantages of each one. This article reviews the basic principles of prostatic mp-magnetic resonance imaging, emphasizing its role on detection, staging and active surveillance of prostate cancer.

A Ressonância Magnética Multiparamétrica tem sido crescentemente utilizada na detecção, localização e estadiamento do cancro da próstata. Combina sequências T2 de alta-resolução com pelo menos duas técnicas funcionais, que incluem o estudo dinâmico pós-gadolínio, a difusão e a espectroscopia. O protocolo ideal aconselha a utilização combinada de uma antena de superfície e uma endorectal; contudo, a antena endorectal é apenas obrigatória para a realização de espectroscopia em aparelhos de 1,5 T. Os níveis de sensibilidade e especificidade na detecção e localização do cancro da próstata têm aumentado com a inclusão das técnicas funcionais, quando comparados com as sequências T2 isoladas, o que é particularmente vantajoso em doentes que têm biópsia negativa, apesar de níveis de PSA persistentemente elevados. Para além disso, a informação adicionada pelas técnicas funcionais aparenta correlacionar-se com a agressividade tumoral, podendo tornar-se útil na selecção de doentes radioterapia focal, cirurgias conservadoras, terapias de ablação focal e vigilância activa. Contudo, são necessários mais estudos para comparar as várias técnicas funcionais e compreender as vantagens e desvantagens de cada uma. Este artigo pretender rever os princípios básicos da Ressonância Magnética prostática multiparamétrica, enfatizando o seu papel na detecção, estadiamento e vigilância activa do cancro da próstata.