Abstract 3219: Changes and intra-individual reliability in computed tomography image-assessed adiposity and skeletal muscles areas after breast cancer surgery

Background: Levels of adiposity and skeletal muscles are prognostic indicators in breast cancer patients; however, data are limited on temporal changes in body composition, particularly in different densities of muscles, before and after mastectomy.

Objectives: We examined the change in CT-assessed adipose tissue and different density of skeletal muscle areas using a high-resolution segmentation method in breast cancer patients before and after surgery.

Methods: This study included 50 newly-diagnosed breast cancer patients who had taken CT scans before and after surgery. We analyzed their third lumbar (L3) CT images to measure the areas of adipose tissue and five-level (from very-high-density to very-low-density) skeletal muscle components. We assessed mean and percent changes in areas using paired t-test and calculated the intra-class correlation (ICC).

Results: Patients’ mean age at diagnosis was 58.3 (SD=12.5) years. The mean duration between scans was 591 (SD=537) days. There was a significant decrease in the areas of subcutaneous adipose tissue (mean change= -36.17 cm2, 11.72% decrease, p=0.029), total adipose tissue (mean change= -45.64 cm2, 10.18% decrease, p=0.032), and very-high-density muscle (mean change= -0.37 cm2, 11.08% decrease, p=0.010). The ratio of total adipose tissue and total skeletal muscle decreased from 3.67 to 3.32 after surgery (mean change= -0.36, 9.81% decrease, p=0.061). There was a strong correlation in adipose tissues and skeletal muscle areas of pre-and post-surgery scans taken within 3 years apart (ICC=0.802 to 0.999, all p<0.05), but the correlations were attenuated in scans taken >3 years apart (ICC = -0.055 to 0.738, all p>0.05).

Conclusion: In this sample of breast cancer patients who have undergone surgery, there was a significant decrease in subcutaneous adipose tissues, total adipose tissues, and very-high-density muscle areas over time. Body composition assessed by CT images is reliable for a 3- year period involving breast cancer surgery. These findings serve as a baseline for prospective studies examining the impact of these changes on breast cancer outcomes.

Keywords: Adipose tissue, skeletal muscle, computed tomography scans, breast cancer, surgery

Citation Format: Livingstone Aduse-Poku, Dheeraj Gopireddy, Mauricio Henandez, Chandana Lall, Joel Divaker, Sara Falzarano, Shahla Masood, Weizhou Zhang, Susmita Datta, Jiang Bian, Ting-Yuan David Cheng. Changes and intra-individual reliability in computed tomography image-assessed adiposity and skeletal muscles areas after breast cancer surgery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3219.

Vulvar Cancer: 2021 Revised FIGO Staging System and the Role of Imaging

Vulvar cancer is a rare gynecological malignancy. It constitutes 5-8% of all gynecologic neoplasms, and squamous cell carcinoma is the most common variant. This article aims to review the etiopathogenesis revised 2021 International Federation of Gynecology and Obstetrics (FIGO) classification and emphasize imaging in the staging of vulvar cancer. The staging has been regulated by FIGO since 1969 and is subjected to multiple revisions. Previous 2009 FIGO classification is limited by the prognostic capability, which prompted the 2021 revisions and issue of a new FIGO classification. Although vulvar cancer can be visualized clinically, imaging plays a crucial role in the staging of the tumor, assessing the tumor extent, and planning the management. In addition, sentinel lymph node biopsy facilitates the histopathological staging of the draining lymph node, thus enabling early detection of tumor metastases and better survival rates.

Ruptured pyomyoma - Rare complication of post-uterine artery embolization: A case report

Leiomyomas, also termed as fibroids, are benign smooth, muscle neoplasms seen in 70–80% of women by the age of 50 years. Uterine artery embolization (UAE) is a minimally invasive procedure that involves cessation of vascular supply to the fibroids, by infusion of gelatinous microspheres into the uterine arteries. Pyomyoma is a suppurative leiomyoma, secondary to infection of necrotic tissue. It is an infrequent complication of uterine artery embolization (UAE). Pyomyoma can lead to sepsis, peritonitis, and respiratory distress syndrome resulting in high morbidity and mortality. Due to its rarity, high suspicion is crucial in the diagnosis, and prompt treatment is recommended to reduce mortality. Ultrasound, computed tomography, and magnetic resonance imaging assist in diagnosis. We present a case of a 44-year-old woman with ruptured pyomyoma, following an UAE intervention. The patient was treated with total abdominal hysterectomy and salpingo-oophorectomy along with peritoneal irrigation and drainage.

Mimics and Pitfalls of Primary Ovarian Malignancy Imaging

The complex anatomy and similarity of imaging features of various pathologies in the pelvis can make accurate radiology interpretation difficult. While prompt recognition of ovarian cancer remains essential, awareness of processes that mimic ovarian tumors can avoid potential misdiagnosis and unnecessary surgery. This article details the female pelvic anatomy and highlights relevant imaging features that mimic extra-ovarian tumors, to help the radiologists accurately build a differential diagnosis of a lesion occupying the adnexa.

Multi-practice survey on MR imaging practice patterns in rectal cancer in the United States

PURPOSE

To investigate practice patterns related to MR technique and structured reporting for MRI of rectal cancer at academic centers and private practice groups in the United States.

METHODS AND MATERIALS

A survey developed by active members of the Society of Abdominal Radiology Rectal and Anal Cancer Disease Focus Panel was sent to 100 private practice and 189 academic radiology groups. The survey asked targeted questions about practice demographics and utilization, technical MR parameters and reporting practices related to MRI of rectal cancer. The results were analyzed using software in an online survey program.

RESULTS

The survey received 47 unique responses from academic (37/47, 78.7%) and private practice (10/47, 21.3%) groups. Most practices report using rectal MR for staging newly diagnosed rectal cancer always (29/47, 61.7%), and less than half always do so for re-staging after neoadjuvant chemoradiation (20/47, 42.6%). Most groups perform between 1 to 5 rectal MR studies for baseline staging per week (32/47, 68.1%) and most groups perform 0 to 2 MR studies for re-staging per week (27/47, 57.4%). Regarding patient preparation and MR technical parameters, there is variability, but a few key points include most practices (27/47, 57.4%) acquire axial T2-weighted images at a slice thickness of 3 mm or less, axial T2-weighted images with 2D acquisition (30/47, 63.8%), a T2-weighted axial oblique sequence through the tumor (43/47, 91.5%), and T2-weighted images without fat suppression (37/47, 78.7%). Equal numbers of groups report using a maximal b-value less than 1000 s/mm² (19/43, 44.2%) and 1000 s/mm² or greater (19/43, 44.2%); the rest were unsure. A substantial portion of respondents do not use intravenous contrast (13/47, 27.7%). Most believe that structured report templates contribute to uniformity of reporting practices (39/47, 83.0%), though there is considerable heterogeneity in usage and included elements.

CONCLUSION

There is considerable technical heterogeneity among respondents' answers and reporting practices in MR for rectal cancer, and most of the groups report reading only a modest number of studies per week. Our findings suggest there may be room for improvement in terms of radiologist education for performance and standardization of clinical practice for MR imaging of rectal cancer.

Response criteria for immunotherapy and the radiologic patterns of immune-related adverse events

Immunotherapy has revolutionized clinical outcomes in both early-stage and advanced-stage malignancies. Immunotherapy has improved patient survival in both solid and hematologic disorders with the potential added benefit of less toxicity compared to conventional cytotoxic chemotherapy. Imaging plays a fundamental role in monitoring treatment response and assessment of immune-related adverse events, e.g. pneumonitis, colitis, etc. Familiarity with the current strategies of immune-related response evaluation and their limitations is essential for radiologists to guide clinicians with their treatment decisions. Radiologists should be aware of the wide spectrum of immune-related adverse events and their various radiological features as well as the patterns of treatment response associated with immunotherapies.

Current update on vaginal malignancies

Primary vaginal cancers are rare and account for 1-3% of all gynecologic malignancies. There are several histological subtypes that affect a wide range of the population. Imaging plays an important role in the diagnosis, staging, and treatment planning of vaginal cancers. This article reviews the relevant anatomy, clinical findings, imaging characteristics, and recent advances in the management of vaginal malignancies.

A Rare Case of Hemorrhagic Giant Adrenal Myelolipoma: Radiographic and Pathologic Correlation

Myelolipomas are rare benign tumors made up of adipose and hematopoietic tissue that commonly occur in the adrenal glands unilaterally. Spontaneous hemorrhage occurs in < 5% of these tumors, and often present as large masses. A 50-year-old male presented with right flank pain that had been growing increasingly worse over a two-week period. Contrast-enhanced Computed Tomography (CT) revealed a large suprarenal 15-cm mass exerting mass effect on the kidney and liver along with possible hemorrhage. T1 fat saturated and T2 non-fat saturated magnetic resonance imaging (MRI) confirmed the diagnosis of a myelolipoma with hemorrhage. The patient was treated with surgical resection of the mass and the follow-up pathology report confirmed a giant hemorrhagic adrenal myelolipoma. Spontaneous hemorrhage of a large myelolipoma measuring 15 cm is a rare entity and the correct imaging needs to be done in order to carry out the appropriate treatment.

MRI and CT bladder segmentation from classical to deep learning based approaches: Current limitations and lessons

Precise determination and assessment of bladder cancer (BC) extent of muscle invasion involvement guides proper risk stratification and personalized therapy selection. In this context, segmentation of both bladder walls and cancer are of pivotal importance, as it provides invaluable information to stage the primary tumor. Hence, multiregion segmentation on patients presenting with symptoms of bladder tumors using deep learning heralds a new level of staging accuracy and prediction of the biologic behavior of the tumor. Nevertheless, despite the success of these models in other medical problems, progress in multiregion bladder segmentation, particularly in MRI and CT modalities, is still at a nascent stage, with just a handful of works tackling a multiregion scenario. Furthermore, most existing approaches systematically follow prior literature in other clinical problems, without casting a doubt on the validity of these methods on bladder segmentation, which may present different challenges. Inspired by this, we provide an in-depth look at bladder cancer segmentation using deep learning models. The critical determinants for accurate differentiation of muscle invasive disease, current status of deep learning based bladder segmentation, lessons and limitations of prior work are highlighted.

Diffusion Weighted Imaging in Unilateral Adrenal Infarction: A Case of Colicky Right Upper Quadrant Pain in a Pregnant Female

Diffusion weighted imaging (DWI) is a magnetic resonance imaging (MRI) non-contrast sequence that can indicate tissue ischemia or infarction. Adrenal infarct may present similarly to biliary or gallbladder pathologies, and the differential diagnosis during emergency work-up can be narrowed utilizing DWI sequences. In this paper, we describe the usefulness of DWI for urgent diagnosis in a case of non-hemorrhagic adrenal infarct of a pregnant female presenting with right upper quadrant pain. Although uncommon, adrenal infarct may occur in patients with hypercoagulability and localizing pain that is unexplained by other imaging modalities. We outline the imaging features of DWI in evaluating adrenal infarct as a safe and time effective application for patients with contraindications to imaging with ionizing radiation.

Spectrum of CT Findings Related to Bowel Adhesions Without Bowel Obstruction: A Comprehensive Imaging Review

Post-operative adhesions can occur following abdominal or pelvic surgery and are a significant cause of morbidity and mortality. Adhesions are an important cause of abdominal complaints, especially chronic abdominal pain, infertility, and bowel obstruction; responsible for an estimated $2.3 billion annual burden in the United States alone. There is a paucity of literature describing CT findings indicative of the presence of adhesions, however, findings suggestive of this entity may be discovered by a discerning eye. Early recognition and diagnosis may be beneficial for reducing consumption of health-care resources related to abdominal complaints. In addition, these findings may impact surgical planning and facilitate recognition of adhesion-related complications, said to be responsible for a significant number of malpractice claims. The following review discusses various CT findings which may indicate the presence of adhesions. These findings may initially be overlooked, but remain valuable as the clinical presentation evolves to become consistent with adhesive disease. Detection of bowel and peritoneal adhesions can be recognized on imaging modalities based on distortion of bowel loops. This pictorial review illustrates the spectrum of findings related to bowel adhesions encountered on computed tomography imaging.

Role of MRI in the Diagnosis of Large Right Adrenal Abscess

Adrenal abscesses are extremely rare occurrences with only scattered case reports reported in the literature. Owing to their rarity, they are not usually considered within the typical differential for cystic adrenal masses discovered on computed tomography (CT) or magnetic resonance imaging (MRI). Accurate and timely diagnosis of these lesions is critical to exclude malignancy and ensure appropriate management. In this case report, we describe a post-traumatic case of adrenal abscess associated with Staphylococcus aureus bacteremia and its differentiation from cystic adrenal masses. Specific emphasis is placed on the imaging features seen on CT and MRI and how these features can be utilized to differentiate it from other adrenal pathologies such as adrenal pseudocyst or cystic adrenocortical neoplasm.

"Renal emergencies: a comprehensive pictorial review with MR imaging"

Superior soft-tissue contrast and high sensitivity of magnetic resonance imaging (MRI) for detecting and characterizing disease may provide an expanded role in acute abdominal and pelvic imaging. Although MRI has traditionally not been exploited in acute care settings, commonly used in biliary obstruction and during pregnancy, there are several conditions in which MRI can go above and beyond other modalities in diagnosis, characterization, and providing functional and prognostic information. In this manuscript, we highlight how MRI can help in further assessment and characterization of acute renal emergencies. Currently, renal emergencies are predominantly evaluated with ultrasound (US) or computed tomography (CT) scanning. US may be limited by various patient factors and technologist experience while CT imaging with intravenous contrast administration can further compromise renal function. With the advent of rapid, robust non-contrast MRI, and magnetic resonance angiography (MRA) imaging studies with short scan times, free-breathing techniques, and lack of ionization radiation, the utility of MRI for renal evaluation might be superior to CT not only in diagnosing an emergent renal process but also by providing functional and prognostic information. This review outlines the clinical manifestations and the key imaging findings for acute renal processes including acute renal infarction, hemorrhage, and renal obstruction, among other entities, to highlight the added value of MRI in evaluating the finer nuances in acute renal emergencies.

Role of precision imaging in esophageal cancer

Esophageal cancer is a major cause of morbidity and mortality worldwide. Recent advancements in the management of esophageal cancer have allowed for earlier detection, improved ability to monitor progression, and superior treatment options. These innovations allow treatment teams to formulate more customized management plans and have led to an increase in patient survival rates. For example, in order for the most effective management plan to be constructed, accurate staging must be performed to determine tumor resectability. This article reviews the multimodality imaging approach involved in making a diagnosis, staging, evaluating treatment response and detecting recurrence in esophageal cancer.

Variability of the Positive Predictive Value of PI-RADS for Prostate MRI across 26 Centers: Experience of the Society of Abdominal Radiology Prostate Cancer Disease-focused Panel

Background Prostate MRI is used widely in clinical care for guiding tissue sampling, active surveillance, and staging. The Prostate Imaging Reporting and Data System (PI-RADS) helps provide a standardized probabilistic approach for identifying clinically significant prostate cancer. Despite widespread use, the variability in performance of prostate MRI across practices remains unknown. Purpose To estimate the positive predictive value (PPV) of PI-RADS for the detection of high-grade prostate cancer across imaging centers. Materials and Methods This retrospective cross-sectional study was compliant with the HIPAA. Twenty-six centers with members in the Society of Abdominal Radiology Prostate Cancer Disease-focused Panel submitted data from men with suspected or biopsy-proven untreated prostate cancer. MRI scans were obtained between January 2015 and April 2018. This was followed with targeted biopsy. Only men with at least one MRI lesion assigned a PI-RADS score of 2-5 were included. Outcome was prostate cancer with Gleason score (GS) greater than or equal to 3+4 (International Society of Urological Pathology grade group ≥2). A mixed-model logistic regression with institution and individuals as random effects was used to estimate overall PPVs. The variability of observed PPV of PI-RADS across imaging centers was described by using the median and interquartile range. Results The authors evaluated 3449 men (mean age, 65 years ± 8 [standard deviation]) with 5082 lesions. Biopsy results showed 1698 cancers with GS greater than or equal to 3+4 (International Society of Urological Pathology grade group ≥2) in 2082 men. Across all centers, the estimated PPV was 35% (95% confidence interval [CI]: 27%, 43%) for a PI-RADS score greater than or equal to 3 and 49% (95% CI: 40%, 58%) for a PI-RADS score greater than or equal to 4. The interquartile ranges of PPV at these same PI-RADS score thresholds were 27%-44% and 27%-48%, respectively. Conclusion The positive predictive value of the Prostate Imaging and Reporting Data System was low and varied widely across centers. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Milot in this issue.

Impact of surgically maximized versus native membranous urethral length on 30-day and long-term pad-free continence after robot-assisted radical prostatectomy

BACKGROUND

Pelvic multiparametric magnetic resonance imaging (mpMRI)-determined membranous urethral length (MUL) and its surgical maximization have been reported to impact early- and long-term pad-free urinary continence after robot-assisted radical prostatectomy (RARP).

OBJECTIVE

The objective of this study was to present evidence (data and video) of important effects on post-RARP continence recovery from both innate mpMRI-assessed and surgical preservation of MUL.

DESIGN SETTING AND PARTICIPANTS

Of 605 men undergoing RARP, 580 with complete follow-up were included: Group 1, prior (N = 355), and Group 2, subsequent (N = 225) to technique change of MUL maximization. Effect of innate, mpMRI-assessed MUL on postoperative continence was assessed.

SURGICAL PROCEDURE

Before technique change, the dorsal venous complex was stapled before transection of the membranous urethra. After the change, the final step of extirpation was transection of the dorsal venous complex and periurethral attachments, thus facilitating surgical maximization of MUL.

MEASUREMENTS

Primary and secondary outcomes for technique change and mpMRI-assessed MUL were both patient-reported 30-day and 1-year pad-free continence after RARP, respectively.

RESULTS

Preoperative prostate-specific antigen, age, and disease aggressiveness were significantly higher in Group 2. After technique change and surgical maximization of MUL, 30-day and 1-year pad-free continence were both significantly improved (p < 0.05). In multivariate analysis, maximization of MUL significantly increased the likelihood of both early- and long-term continence recovery. For men undergoing MUL preservation, mpMRI-assessed MUL>1.4 cm also independently predicted higher 30-day (odds ratio: 4.85, 95% confidence interval: 1.24-18.9) and 1-year continence recovery (odds ratio: 11.26, 95% confidence interval: 1.07-118).

CONCLUSIONS

Prostatic rotation and circumferential release of apical attachments and maximization of MUL improves continence after RARP. Separately, innate MUL>1.4 cm independently increased 30-day and 1-year continence recovery.

PATIENT SUMMARY

Surgeon efforts to maximize MUL during radical prostatectomy are highly encouraged, as maximally preserved MUL likely improves post-RARP continence recovery. In addition, individual patients' mpMRI-assessed MUL (approximately >1.4 cm) independently limits continence recovery.

Angiogenesis in Hepatocellular Carcinoma; Pathophysiology, Targeted Therapy, and Role of Imaging

Hepatocellular carcinoma (HCC) is one of the most common tumors worldwide, usually occurring on a background of liver cirrhosis. HCC is a highly vascular tumor in which angiogenesis plays a major role in tumor growth and spread. Tumor-induced angiogenesis is usually related to a complex interplay between multiple factors and pathways, with vascular endothelial growth factor being a major player in angiogenesis. In the past decade, understanding of tumor-induced angiogenesis has led to the emergence of novel anti-angiogenic therapies, which act by reducing neo-angiogenesis, and improving patient survival. Currently, Sorafenib and Lenvatinib are being used as the first-line treatment for advanced unresectable HCC. However, a disadvantage of these agents is the presence of numerous side effects. A major challenge in the management of HCC patients being treated with anti-angiogenic therapy is effective monitoring of treatment response, which decides whether to continue treatment or to seek second-line treatment. Several criteria can be used to assess response to treatment, such as quantitative perfusion on cross-sectional imaging and novel/emerging MRI techniques, including a host of known and emerging biomarkers and radiogenomics. This review addresses the pathophysiology of angiogenesis in HCC, accurate imaging assessment of angiogenesis, monitoring effects of anti-angiogenic therapy to guide future treatment and assessing prognosis.

Adrenal cortical carcinoma: pathology, genomics, prognosis, imaging features, and mimics with impact on management

Adrenocortical carcinoma (ACC) is a rare tumor with a poor prognosis. Most tumors are either metastatic or locally invasive at the time of diagnosis. Differentiation between ACC and other adrenal masses depends on clinical, biochemical, and imaging factors. This review will discuss the genetics, pathological, and imaging feature of ACC.

Evaluation of a Diuresis Enhanced Non-Contrast Computed Tomography for Kidney Stones Protocol to Maximize Collecting System Distention

Purpose: In urolithiasis patients, preoperative non-contrast computed tomography (NCCT) commonly fails to provide sufficient distention of the renal collecting system to allow reliable preoperative planning for how best to approach a stone. Our objective was to evaluate the effect of a novel protocol, including oral hydration and an oral diuretic, on the distention of the renal collecting system. Patients and Methods: Twenty patients with a prior NCCT, who were scheduled to undergo a subsequent NCCT for urolithiasis assessment, were enrolled. Each patient was instructed to ingest 1 L of water and 20 mg of oral furosemide 30 to 60 minutes before their scan (DRINK [DiuResIs Enhanced Non-contrast Computed Tomography for Kidney Stones] protocol). Patients' prior NCCT scan (non-DRINK) was used for comparison. Three-dimensional (3D) reconstruction of DRINK and non-DRINK NCCT studies was performed to determine the volume and surface area of the collecting system. In addition, three faculty endourologists measured the width of the upper and lower pole infundibula and renal pelvis in the axial, coronal, and sagittal views. Results: Among the 20 patients, 13 completed the DRINK protocol as specified. For these 13 patients, 3D reconstruction of the DRINK study collecting systems showed a 63% and a 36% increase in collecting system volume and surface area, respectively (p = 0.02 and p < 0.01, respectively). Also, measurements of the CT images demonstrated a significant (p < 0.05) increase in the collecting system widths in 67% of measurements. Conclusion: The DRINK protocol significantly increased the visible collecting system volume and surface area; in the majority of cases, the upper and lower pole infundibular widths and the width of the renal pelvis were also expanded.

Rare Treatment for a Rare Tumor: Cryoablation of a Granular Cell Tumor

Background

Granular cell tumors (GCTs) or Abrikossoff's tumors are rare neoplasms known to originate from Schwann cells in the peripheral nervous system. These lesions are usually benign; malignancy only occurs in 1-2% of cases. Surgical resection is the traditional treatment method for GCTs, but it poses several risks and disadvantages related to the surgical incompatibility of the patient, the extended recovery time, and the chance of relapse. Cryoablation is becoming an increasingly favored method of treatment for tumors, both benign and malignant, due to its minimal invasiveness, natural analgesic properties, and ability to stimulate antitumor immunity. Cryoablation may contribute to the prevention of secondary and metastatic tumor growth in cases of malignancy by preserving tumor-associated antigen molecules for recognition by cell-mediated immunity.

Methods

This article describes a novel method for GCT treatment using cryoablation. This technique exposes tumor tissue to extreme cold temperatures, effectively destroying tumor cells by irreversibly compromising their plasma membranes. To our knowledge, this is the first report in the literature of cryoablative techniques being used for GCT.

Results

Cryoablation of this mass was successful with no complications. CT images during the procedure demonstrated circumferential coverage of the entire lesion with no injury to the surrounding tissues.

Conclusion

Cryoablation can be used as an alternative to surgical intervention to treat malignant GCTs. This procedure is minimally invasive, less painful, and potentially effective in promoting antitumor immunity.

Beyond adenocarcinoma: MRI of uncommon rectal neoplasms and mimickers

OBJECTIVE

To provide a review of rare rectal tumors beyond adenocarcinoma.

RESULTS

Rectal cancer is a common malignancy, both in the United States and abroad. In addition to adenocarcinoma, abdominal radiologists will encounter a variety of other less common rectal masses, both benign and malignant neoplasms as well as non-neoplastic mimickers. Familiarity with these conditions and their characteristic features on MRI is useful in clinical practice. In this article, a number of such conditions are discussed, with an emphasis on distinguishing features on MRI of the rectum.

CONCLUSION

Familiarity with the MRI features of rare rectal tumors beyond adenocarcinoma, as well as a small number of non-neoplastic mimics, is important for abdominal imagers to make diagnostic differentials and to assist in treatment planning.

Current controversy, confusion, and imprecision in the use and interpretation of rectal MRI

There has been a rapid increase in the utilization of MRI in rectal cancer staging in the USA essentially replacing endorectal ultrasound and mimicking the trend in Europe seen in the 1990s and 2000s. Accompanying this trend, there is a demand, and recognized need, for greater precision and clarification of confusing, misunderstood and poorly understood concepts, facts, statements and nomenclature regarding rectal cancer and the use of pelvic MRI for diagnosis. As such, this Review, part evidence-based and part expert opinion, will attempt to elucidate and clarify several concepts the authors have encountered in 25 years of imaging rectal cancer, focusing on MRI.

Current controversy, confusion, and imprecision in the use and interpretation of rectal MRI

There has been a rapid increase in the utilization of MRI in rectal cancer staging in the USA essentially replacing endorectal ultrasound and mimicking the trend in Europe seen in the 1990s and 2000s. Accompanying this trend, there is a demand, and recognized need, for greater precision and clarification of confusing, misunderstood and poorly understood concepts, facts, statements and nomenclature regarding rectal cancer and the use of pelvic MRI for diagnosis. As such, this Review, part evidence-based and part expert opinion, will attempt to elucidate and clarify several concepts the authors have encountered in 25 years of imaging rectal cancer, focusing on MRI.

Usefulness of CT texture analysis in differentiating benign and malignant renal tumours

AIM

To elucidate visually imperceptible differences between benign and malignant renal tumours using computed tomography texture analysis (CTTA) using filtration histogram based parameters.

MATERIALS AND METHODS

A retrospective study was performed by texture analysis of pretreatment contrast-enhanced CT examinations in 354 histopathologically confirmed renal cell carcinomas (RCCs) and 147 benign renal tumours. A region-of-interest was drawn encompassing the largest cross-section of the tumour on venous phase axial CT. CTTA features of entropy, kurtosis, mean positive pixel density, and skewness at different spatial filters were calculated and compared in an attempt to differentiate benign lesions from malignancy.

RESULTS

Entropy with fine spatial filter was significantly higher in RCC than benign renal tumours (p=0.022). Entropy with fine and medium filters was higher in RCC than lipid-poor angiomyolipoma (p=0.050 and 0.052, respectively). Entropy >5.62 had high specificity of 85.7%, but low sensitivity of 31.3%, respectively, for predicting RCC.

CONCLUSIONS

Differences in entropy were helpful in differentiating RCC from lipid-poor angiomyolipoma, and chromophobe RCC from oncocytoma. This technique may be useful to differentiate lesions that appear equivocal on visual assessment or alter management in poor surgical candidates.

PI-RADS Version 2 Is an Excellent Screening Tool for Clinically Significant Prostate Cancer as Designated by the Validated International Society of Urological Pathology Criteria: A Retrospective Analysis

OBJECTIVES

To assess the utility of multiparametric MRI in detecting clinically significant prostate cancer (csPCa) by comparing PI-RADSv2 scores with International Society of Urological Pathology (ISUP) pathologic grading criteria.

METHODS

Data from 137 patients were retrospectively analyzed. PI-RADSv2 scores were compared with pathologic grade using ISUP criteria. Pathologic grades were divided into clinically significant (groups 3-5) and clinically insignificant lesions (groups 1-2). Chi-squared analysis was performed for to assess correlation.

RESULTS

Sensitivity and specificity of PI-RADSv2 score 3-5 lesions for detecting csPCa was 100% and 18.5%, respectively. Negative predictive value (NPV) is 100% for these lesions. When considering only PI-RADSv2 score 4-5 lesions, sensitivity decreases to 90% and specificity increases to 67.5%, with a NPV of 98.5%. When only PI-RADSv2 score 5 lesions are considered, sensitivity decreases to 50% and specificity increases to 90%, with a NPV of 95%.

CONCLUSIONS

Multiparametric MRI has excellent sensitivity for detecting csPCa. Specificity is poor for PI-RADSv2 score 3 lesions but improves significantly for PI-RADSv2 score 4 and 5 lesions. Overall, mpMRI is an excellent screening tool for csPCa, as designated by the recently validated ISUP criteria.

ADVANCES IN KNOWLEDGE

Multiple limitations of the longstanding Gleason pathologic scoring system have led to the development of new ISUP pathologic criteria, which is more focused on the clinical significance of lesions. There are currently insufficient studies evaluating and validating the ISUP criteria with PIRADS v2 evaluation of the prostate.