How Imaging Advances Are Defining the Future of Precision Radiation Therapy.

Radiation therapy is fundamental in the treatment of cancer. Imaging has always played a central role in radiation oncology. Integrating imaging technology into irradiation devices has increased the precision and accuracy of dose delivery and decreased the toxic effects of the treatment. Although CT has become the standard imaging modality in radiation therapy, the development of recently introduced next-generation imaging techniques has improved diagnostic and therapeutic decision making in radiation oncology. Functional and molecular imaging techniques, as well as other advanced imaging modalities such as SPECT, yield information about the anatomic and biologic characteristics of tumors for the radiation therapy workflow. In clinical practice, they can be useful for characterizing tumor phenotypes, delineating volumes, planning treatment, determining patients' prognoses, predicting toxic effects, assessing responses to therapy, and detecting tumor relapse. Next-generation imaging can enable personalization of radiation therapy based on a greater understanding of tumor biologic factors. It can be used to map tumor characteristics, such as metabolic pathways, vascularity, cellular proliferation, and hypoxia, that are known to define tumor phenotype. It can also be used to consider tumor heterogeneity by highlighting areas at risk for radiation resistance for focused biologic dose escalation, which can impact the radiation planning process and patient outcomes. The authors review the possible contributions of next-generation imaging to the treatment of patients undergoing radiation therapy. In addition, the possible roles of radio(geno)mics in radiation therapy, the limitations of these techniques, and hurdles in introducing them into clinical practice are discussed. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Radiomics in CT and MR imaging of the liver and pancreas: tools with potential for clinical application.

Radiomics allows the extraction of quantitative imaging features from clinical magnetic resonance imaging (MRI) and computerized tomography (CT) studies. The advantages of radiomics have primarily been exploited in oncological applications, including better characterization and staging of oncological lesions and prediction of patient outcomes and treatment response. The potential introduction of radiomics in the clinical setting requires the establishment of a standardized radiomics pipeline and a quality assurance program. Radiomics and texture analysis of the liver have improved the differentiation of hypervascular lesions such as adenomas, focal nodular hyperplasia, and hepatocellular carcinoma (HCC) during the arterial phase, and in the pretreatment determination of HCC prognostic factors (e.g., tumor grade, microvascular invasion, Ki-67 proliferation index). Radiomics of pancreatic CT and MR images has enhanced pancreatic ductal adenocarcinoma detection and its differentiation from pancreatic neuroendocrine tumors, mass-forming chronic pancreatitis, or autoimmune pancreatitis. Radiomics can further help to better characterize incidental pancreatic cystic lesions, accurately discriminating benign from malignant intrapancreatic mucinous neoplasms. Nonetheless, despite their encouraging results and exciting potential, these tools have yet to be implemented in the clinical setting. This non-systematic review will describe the essential steps in the implementation of the radiomics and feature extraction workflow from liver and pancreas CT and MRI studies for their potential clinical application. A succinct overview of reported radiomics applications in the liver and pancreas and the challenges and limitations of their implementation in the clinical setting is also discussed, concluding with a brief exploration of the future perspectives of radiomics in the gastroenterology field.

Interdisciplinary Spanish consensus on a watch-and-wait approach for rectal cancer.

Watch-and-wait has emerged as a new strategy for the management of rectal cancer when a complete clinical response is achieved after neoadjuvant therapy. In an attempt to standardize this new clinical approach, initiated by the Spanish Cooperative Group for the Treatment of Digestive Tumors (TTD), and with the participation of the Spanish Association of Coloproctology (AECP), the Spanish Society of Pathology (SEAP), the Spanish Society of Gastrointestinal Endoscopy (SEED), the Spanish Society of Radiation Oncology (SEOR), and the Spanish Society of Medical Radiology (SERAM), we present herein a consensus on a watch-and-wait approach for the management of rectal cancer. We have focused on patient selection, the treatment schemes evaluated, the optimal timing for evaluating the clinical complete response, the oncologic outcomes after the implementation of this strategy, and a protocol for surveillance of these patients.

Testicular Evaluation Using Shear Wave Elastography (SWE) in Patients with Varicocele.

PURPOSE: To assess the possible influence of the presence of varicocele on the quantification of testicular stiffness. METHODS: Ultrasound with shear wave elastography (SWE) was performed on 48 consecutive patients (96 testicles) referred following urology consultation for different reasons. A total of 94 testes were studied and distributed in three groups: testes with varicocele (group A, n = 19), contralateral normal testes (group B; n = 13) and control group (group C, n = 62). Age, testicular volume and testicular parenchymal tissue stiffness values of the three groups were compared using the Kruskal-Wallis test. RESULTS: The mean age of the patients was 42.1 ± 11.1 years. The main reason for consultation was infertility (64.6%). The mean SWE value was 4 ± 0.4 kPa (kilopascal) in group A, 4 ± 0.5 kPa in group B and 4.2 ± 0.7 kPa in group C or control. The testicular volume was 15.8 ± 3.8 mL in group A, 16 ± 4.3 mL in group B and 16.4 ± 5.9 mL in group C. No statistically significant differences were found between the three groups in terms of age, testicular volume and tissue stiffness values. CONCLUSION: Tissue stiffness values were higher in our control group (healthy testicles) than in patients with varicocele.

CT-Based Radiomics to Predict KRAS Mutation in CRC Patients Using a Machine Learning Algorithm: A Retrospective Study.

Colorectal cancer (CRC) is one of the most common types of cancer worldwide. The KRAS mutation is present in 30-50% of CRC patients. This mutation confers resistance to treatment with anti-EGFR therapy. This article aims at proving that computer tomography (CT)-based radiomics can predict the KRAS mutation in CRC patients. The piece is a retrospective study with 56 CRC patients from the Hospital of Santiago de Compostela, Spain. All patients had a confirmatory pathological analysis of the KRAS status. Radiomics features were obtained using an abdominal contrast enhancement CT (CECT) before applying any treatments. We used several classifiers, including AdaBoost, neural network, decision tree, support vector machine, and random forest, to predict the presence or absence of KRAS mutation. The most reliable prediction was achieved using the AdaBoost ensemble on clinical patient data, with a kappa and accuracy of 53.7% and 76.8%, respectively. The sensitivity and specificity were 73.3% and 80.8%. Using texture descriptors, the best accuracy and kappa were 73.2% and 46%, respectively, with sensitivity and specificity of 76.7% and 69.2%, also showing a correlation between texture patterns on CT images and KRAS mutation. Radiomics could help manage CRC patients, and in the future, it could have a crucial role in diagnosing CRC patients ahead of invasive methods.

Current and Advanced Applications of Gadoxetic Acid-enhanced MRI in Hepatobiliary Disorders.

Gadoxetic acid is an MRI contrast agent that has specific applications in the study of hepatobiliary disease. After being distributed in the vascular and extravascular spaces during the dynamic phase, gadoxetic acid is progressively taken up by hepatocytes and excreted to the bile ducts during the hepatobiliary phase. The information derived from the enhancement characteristics during dynamic and hepatobiliary phases is particularly relevant in the detection and characterization of focal liver lesions and in the evaluation of the structure and function of the liver and biliary system. The use of new MRI sequences and advanced imaging techniques (eg, relaxometry, multiparametric imaging, and analysis of heterogeneity), the introduction of artificial intelligence, and the development of biomarkers and radiomic and radiogenomic tools based on gadoxetic acid-enhanced MRI findings will play an important role in the future in assessing liver function, chronic liver disease, and focal liver lesions; in studying biliary pathologic conditions; and in predicting treatment responses and prognosis. © RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Usefulness of balanced SSFP sequence in robot-assisted MRI-guided prostate biopsy: Beyond scouting.

OBJECTIVES: To determine whether bSSFP images are useful for visualizing prostatic lesionsin MRI-guided in-bore transrectal biopsy. METHODS: This retrospective studyincluded 67 men witha single suspected cancer on MRI (PI-RADS 2.1 category ≥ 3) who underwent in-bore transrectal MRI-guided biopsy. Two uroradiologists independently rated lesion conspicuity on a 3-point scale (1:non-visible, 2:slightly visible, 3:clearly visible) on T2WI, DWI, and balanced SSFP.We used measures of frequency to compare lesion conspicuity in 3 sequences. We used Cohen's kappa to assess inter-rater reliability. RESULTS: Lesions were rated (1) non-visible in 18 % (12/67) of T2WI, 5 % (3/67) of DWI, and 10 % (7/67) of balanced SSFP images, (2) slightly visible in 56 % (37/67) on T2WI, 13 % (9/67) on DWI, and 48 % (32/67) on bSSFP, and (3) clearly visible in 27 %(18/67) on T2WI, 82 % (55/67) on DWI, and 42 % (28/67) on bSSFP. Lesions classified as prostate cancer at histology were slightly-clearly visible in 85 % (41/48) on T2WI, 100 % (48/48) on DWI, and 94 % (45/48) on bSSFP. Lesions classified as PI-RADS ≥ 4 were visible in 87 % (47/54) of T2WI, 100 % (54/54) of DWI, and 93 % (50/54) of bSSFP. Gleason ≥ 3 + 4 lesions were visible in 85 % (37/43) of T2WI, 100 % (43/43) of DWI, and 95 % (41/43) of bSSFP. Inter-rater agreement was excellent for T2WI (k = 0.97) and bSSFP (k = 0.94), and good for DWI (k = 0.75). CONCLUSION: Balanced SSFP is useful for visualizing prostatic lesions. Replacing T2WI with balanced SSFP can reduce the duration of in-bore transrectal MRI-guided biopsy.

Follow-up of primary melanoma patients with high risk of recurrence: recommendations based on evidence and consensus

In spite of the good prognosis of patients with early-stage melanoma, there is a substantial proportion of them that develop local or distant relapses. With the introduction of targeted and immune therapies for advanced melanoma, including at the adjuvant setting, early detection of recurrent melanoma and/or second primary lesions is crucial to improve clinical outcomes. However, there is a lack of universal guidelines regarding both frequency of surveillance visits and diagnostic imaging and/or laboratory evaluations. In this article, a multidisciplinary expert panel recommends, after careful review of relevant data in the field, a consensus- and experience-based follow-up strategy for melanoma patients, taking into account prognostic factors and biomarkers and the high-risk periods and patterns of recurrence in each (sub) stage of the disease. Apart from the surveillance intensity, healthcare professionals should focus on patients’ education to perform regular self-examinations of the skin and palpation of lymph nodes. (AU)

Usefulness of Computed Tomography Angiography in the Preoperative Workup of Patients With Colorectal Cancer.

OBJECTIVES: The objective of this study is to analyze the main patterns of branching of the inferior mesenteric artery (IMA) and to determine if your knowledge changes the surgical strategy in the colorectal cancer. METHODS: This retrospective study included 63 patients with cancer of the sigmoid or rectum. We assessed the patterns of IMA in 3 subtypes: type A (independent left colic artery [LCA]), type B (LCA and sigmoid artery arising in a common trunk) and type C (LCA, sigmoid artery, and superior rectal artery with a common origin). Colorectal surgeons evaluated how the vascular map changed the type of IMA ligation. RESULTS: Inferior mesenteric artery branching was classified as type A in 55.6% patients, type B in 23.8%, and type C in 20.6%. Knowledge of the vascular map changed the type of ligation from high to low in 20 of the 50 patients who were candidates for surgery. The change was possible in tumors located in the sigmoid colon and the rectosigmoid junction with the type A or B branching. CONCLUSIONS: Preoperative Multidetector Computed Tomography angiography can define the pattern of IMA branching. Based on this information, a low ligation can be performed in tumors located in sigmoid colon and rectosigmoid junction with IMA branching types A and B.

Follow-up of primary melanoma patients with high risk of recurrence: recommendations based on evidence and consensus.

In spite of the good prognosis of patients with early-stage melanoma, there is a substantial proportion of them that develop local or distant relapses. With the introduction of targeted and immune therapies for advanced melanoma, including at the adjuvant setting, early detection of recurrent melanoma and/or second primary lesions is crucial to improve clinical outcomes. However, there is a lack of universal guidelines regarding both frequency of surveillance visits and diagnostic imaging and/or laboratory evaluations. In this article, a multidisciplinary expert panel recommends, after careful review of relevant data in the field, a consensus- and experience-based follow-up strategy for melanoma patients, taking into account prognostic factors and biomarkers and the high-risk periods and patterns of recurrence in each (sub) stage of the disease. Apart from the surveillance intensity, healthcare professionals should focus on patients' education to perform regular self-examinations of the skin and palpation of lymph nodes.

"Rectal cancer survival: A retrospective analysis of MRI features and their association with prognosis".

PURPOSE: To assess rectal cancer aggressiveness using magnetic resonance (MR) imaging features and to investigate their relationship with patient prognosis. MATERIALS AND METHODS: Clinical information and Pelvic MR scans of 106 consecutive patients with primary rectal cancer (RC) were analyzed. Clinical symptoms, age, sex, tumor location, and patient´s survival were recorded. The variables investigated by MR were: depth or mural/extramural tumor involvement, distance to mesorectal margin, lymph node involvement, vascular, peritoneal or sphincter complex infiltration. The association between imaging features and disease-free survival (DFS) was also assessed using a Kaplan-Meier model. Differences between survival curves were tested for significance using the Mantel-Cox LogRank test. RESULTS: The final study population was 106 patients (65 males, 41 females). The median age was 69.5 years (range, 39-92 years). No significant differences were found between death risk and sex, age or tumor location (p>0,05). However, the relative risk (RR) of tumor mortality increased significantly with the presence of the variables: vascular infiltration (×5), T4 tumors (× 4.57), N2 lymph node involvement (more than 3 affected nodes × 4.11) and mesorectal fascia involvement (× 3,77). CONCLUSION: Tumor extension, number of pathological lymph nodes, mesorectal fascia involvement and vascular infiltration values obtained on initial MR imaging staging showed a significant difference for disease-free survival in RC at six years of control.

Assessing Immunotherapy with Functional and Molecular Imaging and Radiomics.

Immunotherapy is changing the treatment paradigm for cancer and has introduced new challenges in medical imaging. Because not all patients benefit from immunotherapy, pretreatment imaging should be performed to identify not only prognostic factors but also factors that allow prediction of response to immunotherapy. Follow-up studies must allow detection of nonresponders, without confusion of pseudoprogression with real progression to prevent premature discontinuation of treatment that can benefit the patient. Conventional imaging techniques and classic tumor response criteria are limited for the evaluation of the unusual patterns of response that arise from the specific mechanisms of action of immunotherapy, so advanced imaging methods must be developed to overcome these shortcomings. The authors present the fundamentals of the tumor immune microenvironment and immunotherapy and how they influence imaging findings. They also discuss advances in functional and molecular imaging techniques for the assessment of immunotherapy in clinical practice, including their use to characterize immune phenotypes, assess patient prognosis and response to therapy, and evaluate immune-related adverse events. Finally, the development of radiomics and radiogenomics in these therapies and the future role of imaging biomarkers for immunotherapy are discussed. Online supplemental material is available for this article. ©RSNA, 2020.

Dietary Fat Patterns and Outcomes in Acute Pancreatitis in Spain.

Background/Objective: Evidence from basic and clinical studies suggests that unsaturated fatty acids (UFAs) might be relevant mediators of the development of complications in acute pancreatitis (AP). Objective: The aim of this study was to analyze outcomes in patients with AP from regions in Spain with different patterns of dietary fat intake. Materials and Methods: A retrospective analysis was performed with data from 1,655 patients with AP from a Spanish prospective cohort study and regional nutritional data from a Spanish cross-sectional study. Nutritional data considered in the study concern the total lipid consumption, detailing total saturated fatty acids, UFAs and monounsaturated fatty acids (MUFAs) consumption derived from regional data and not from the patient prospective cohort. Two multivariable analysis models were used: (1) a model with the Charlson comorbidity index, sex, alcoholic etiology, and recurrent AP; (2) a model that included these variables plus obesity. Results: In multivariable analysis, patients from regions with high UFA intake had a significantly increased frequency of local complications, persistent organ failure (POF), mortality, and moderate-to-severe disease in the model without obesity and a higher frequency of POF in the model with obesity. Patients from regions with high MUFA intake had significantly more local complications and moderate-to-severe disease; this significance remained for moderate-to-severe disease when obesity was added to the model. Conclusions: Differences in dietary fat patterns could be associated with different outcomes in AP, and dietary fat patterns may be a pre-morbid factor that determines the severity of AP. UFAs, and particulary MUFAs, may influence the pathogenesis of the severity of AP.

Corpus cavernosum thrombosis: the membrane may play its role / Trombosis del cuerpo cavernoso: la membrana desempeña su papel

Partial thrombosis of corpus cavernosum is an uncommon condition that needs a high level of suspicious to be diagnosed. Imaging techniques may be very useful, and MR is the state-of-the-art technique. We present a case of a young male who presented to the emergency department with perineal and painful mass. MR imaging clearly depicted a thrombosed corpus cavernosum and a bilateral membrane that is possibly the underlying predisposing condition. With only conservative treatment the patient had an excellent outcome

La trombosis parcial del cuerpo cavernoso es una rara entidad que necesita de un alto grado de sospecha para su diagnóstico. Las técnicas de diagnóstico por la imagen pueden ser de gran utilidad y la resonancia magnética (RM) es la mejor modalidad disponible. Presentamos el caso de un joven varón que acude al servicio de urgencias con una masa perineal dolorosa. La RM diagnostica trombosis del cuerpo cavernoso y la existencia de una membrana bilateral, un posible factor predisponente. Con apenas tratamiento conservador, el paciente tuvo una excelente evolución clínica

Corpus cavernosum thrombosis: The membrane may play its role.

Partial thrombosis of corpus cavernosum is an uncommon condition that needs a high level of suspicious to be diagnosed. Imaging techniques may be very useful, and MR is the state-of-the-art technique. We present a case of a young male who presented to the emergency department with perineal and painful mass. MR imaging clearly depicted a thrombosed corpus cavernosum and a bilateral membrane that is possibly the underlying predisposing condition. With only conservative treatment the patient had an excellent outcome.

Radiologic Clues to Cerebral Venous Thrombosis.

Cerebral venous thrombosis (CVT) is uncommon, representing approximately 0.5% of all cases of cerebrovascular disease worldwide. Many factors, alone or combined, can cause CVT. Although CVT can occur at any age, it most commonly affects neonates and young adults. CVT is difficult to diagnose clinically because patients can present with a wide spectrum of nonspecific manifestations, the most common of which are headache in 89%-91%, focal deficits in 52%-68%, and seizures in 39%-44% of patients. Consequently, imaging is fundamental to its diagnosis. MRI is the most sensitive and specific technique for diagnosis of CVT. The different MRI sequences, with and without the use of contrast material, have variable strengths. Contrast material-enhanced MR venography has the highest accuracy compared with sequences without contrast enhancement.Online supplemental material is available for this article.©RSNA, 2019.

Update on Whole-body MRI in Musculoskeletal Applications.

Whole-body magnetic resonance imaging (WB-MRI) is a powerful tool increasingly used to assess oncologic and nononcologic diseases. WB-MRI provides information about diffuse multifocal pathologies with excellent anatomical definition through high soft tissue contrast and spatial resolution as well as valuable functional information from diffusion-weighted images. In addition to its roles in establishing the diagnosis and assessing the extent and severity of disease, WB-MRI is also useful for monitoring the response to treatment for malignant and benign systemic diseases affecting the musculoskeletal system. This article reviews and updates the applications of WB-MRI in current practice, discussing the role of this helpful tool in various conditions involving the musculoskeletal system including bone metastases, hematologic cancers, inflammatory processes, infections, and multisystemic-multifocal bone, nerve, vascular, and muscle/soft tissue disorders, as well as other idiopathic conditions.

How clinical imaging can assess cancer biology.

Human cancers represent complex structures, which display substantial inter- and intratumor heterogeneity in their genetic expression and phenotypic features. However, cancers usually exhibit characteristic structural, physiologic, and molecular features and display specific biological capabilities named hallmarks. Many of these tumor traits are imageable through different imaging techniques. Imaging is able to spatially map key cancer features and tumor heterogeneity improving tumor diagnosis, characterization, and management. This paper aims to summarize the current and emerging applications of imaging in tumor biology assessment.

Muscle MRI in a large cohort of patients with oculopharyngeal muscular dystrophy.

BACKGROUND AND OBJECTIVE: Oculopharyngeal muscular dystrophy (OPMD) is a genetic disorder caused by an abnormal expansion of GCN triplets within the PABPN1 gene. Previous descriptions have focused on lower limb muscles in small cohorts of patients with OPMD, but larger imaging studies have not been performed. Previous imaging studies have been too small to be able to correlate imaging findings to genetic and clinical data. METHODS: We present cross-sectional, T1-weighted muscle MRI and CT-scan data from 168 patients with genetically confirmed OPMD. We have analysed the pattern of muscle involvement in the disease using hierarchical analysis and presented it as heatmaps. Results of the scans were correlated with genetic and clinical data. RESULTS: Fatty replacement was identified in 96.7% of all symptomatic patients. The tongue, the adductor magnus and the soleus were the most commonly affected muscles. Muscle pathology on MRI correlated positively with disease duration and functional impairment. CONCLUSIONS: We have described a pattern that can be considered characteristic of OPMD. An early combination of fat replacement in the tongue, adductor magnus and soleus can be helpful for differential diagnosis. The findings suggest the natural history of the disease from a radiological point of view. The information generated by this study is of high diagnostic value and important for clinical trial development.

Scrotal Peripheral Primitive Neuroectodermal Tumor.

The peripheral primitive neuroectodermal tumor (pPNET) is a rare malignant tumor originating from neuroectoderm that usually occurs in children or adolescent and is frequently located in the extremities, chest cavity, pelvic cavity and chest wall. We present a rare case of an 84-year-old man with a history of pPNET in the scrotal sac, to our knowledge not previously published in the literature. The presence of a large irreducible mass in the inguinal sac forced to exclude a tumor. Ultrasound and MRI are very useful modalities to assess the location of the mass, its dependency from any organ and the tumoral internal structure. Molecular imaging with the detection of EWS-FLI1 fusion transcripts is useful for the diagnosis and differential diagnosis of Ewing sarcoma/pPNETs.