Spectrum of Cognitive Biases in Diagnostic Radiology.

Cognitive biases are systematic thought processes involving the use of a filter of personal experiences and preferences arising from the tendency of the human brain to simplify information processing, especially when taking in vast amounts of data such as from imaging studies. These biases encompass a wide spectrum of thought processes and frequently overlap in their concepts, with multiple biases usually in operation when interpretive and perceptual errors occur in radiology. The authors review the gamut of cognitive biases that occur in radiology. These biases are organized according to their expected stage of occurrence while the radiologist reads and interprets an imaging study. In addition, the authors propose several additional cognitive biases that have not yet, to their knowledge, been defined in the radiologic literature but are applicable to diagnostic radiology. Case examples are used to illustrate potential biases and their impact, with emergency radiology serving as the clinical paradigm, given the associated high imaging volumes, wide diversity of imaging examinations, and rapid pace, which can further increase a radiologist's reliance on biases and heuristics. Potential strategies to recognize and overcome one's personal biases at each stage of image interpretation are also discussed. Awareness of such biases and their unintended effects on imaging interpretations and patient outcomes may help make radiologists cognizant of their own biases that can result in diagnostic errors. Identification of cognitive bias in departmental and systematic quality improvement practices may represent another tool to prevent diagnostic errors in radiology. ©RSNA, 2024 See the invited commentary by Larson in this issue.

Spectrum of MRI Features of Mucin-producing Neoplasms in the Abdomen and Pelvis.

Mucin-producing neoplasms in the abdomen and pelvis are a distinct entity, separate from simple fluid-containing neoplasms and loculated fluid collections. Mucin is a thick gelatinous substance and-owing to its high water content-has imaging features that can be mistaken for those of simple fluid-containing neoplasms with multiple imaging modalities. However, mucin-producing neoplasms arise from specific organs in the abdomen and pelvis, with unique imaging appearances, knowledge of which is important to guide accurate diagnosis and management. With its large field of view and high soft-tissue resolution, MRI has advantages over other imaging modalities in characterizing these neoplasms. The authors focus on the spectrum of MRI features of such mucin-producing neoplasms and illustrate how-despite a varied organ origin-some of these neoplasms share similar MRI and histopathologic features, thereby helping narrow the differential diagnosis. One common finding in these tumors is that the presence of internal complexity and solid enhancing components increases as the degree of malignant transformation increases. Lack of internal complexity generally indicates benignity. These tumors have a varied range of prognosis; for example, a low-grade appendiceal mucinous neoplasm is indicative of a good prognosis, while a mucinous tumor of the rectum is known to manifest at an early age with aggressive behavior and poorer prognosis compared with its nonmucinous counterpart. Online supplemental material is available for this article. ©RSNA, 2022.

Yield of pelvic CT in emergency department patients undergoing CT torso for generalized or multiple complaints.

PURPOSE: To evaluate the utility of pelvic computed tomography (CT) in emergency department (ED) patients undergoing chest CT angiogram (CTA) for chest pain or suspected pulmonary embolism (PE) followed by abdominopelvic CT in the same session for additional multisystem or generalized complaints. METHODS: This retrospective study included consecutive adult ED patients from January 2017 to December 2019 who underwent CTA for suspected PE followed by portovenous abdominopelvic CT for multisystem or generalized complaints. Patient demographics, vitals, laboratory values, exam indication, malignancy history, and recent surgery/intervention were recorded. CT reports were reviewed for acute chest, abdomen, and/or pelvic pathology. RESULTS: There were 400 patients with 243 (61%) women and mean age of 59.8 years. Acute pelvic findings were seen in 11% (45/400). In 53% (24/45) of these, pelvic pathology could be diagnosed based on the abdominal portion of the CT. Five percent (21/400) of patients demonstrated isolated acute pelvic findings with 86% of these (18/21) clinically suspected prior to imaging. Acute pelvic pathology was associated with female gender (p = 0.015) and elevated white blood cell count (WBC) (p = 0.03). Specific pelvic CT indications and female gender were significantly associated with (p = 0.02 each) and independent predictors of isolated acute pelvic pathology. CONCLUSION: In ED patients undergoing chest CTA for chest pain or suspected PE combined with abdominopelvic CT, the presence of acute pelvic-related pathology not visualized on abdominal CT is low. For this ED patient cohort, pelvic CT may not be necessary in men with normal WBC and a low pre-imaging clinical suspicion for acute pelvic pathology.

Diagnostic Utility of CT and Fluoroscopic Esophagography for Suspected Esophageal Perforation in the Emergency Department.

OBJECTIVE. We evaluated the diagnostic utility of CT in emergency department (ED) patients with suspected esophageal perforation and assessed whether subsequent fluoroscopic esophagography is necessary. MATERIALS AND METHODS. This retrospective study included consecutive adult patients presenting to an urban academic tertiary care ED from January 1, 2000, to August 31, 2017, who underwent CT and fluoroscopic esophagography within 1 calendar day (< 27 hours) of each other for suspected esophageal perforation. The use of oral or IV contrast material and the CT findings (i.e., pneumomediastinum, pleural effusion, pneumothorax, unexplained mediastinal fluid or stranding, esophageal wall air or frank esophageal wall disruption, or extraluminal oral contrast material) were documented. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Surgical or procedural intervention results or clinical follow-up results were the reference standard. RESULTS. One hundred three patients met the inclusion criteria. Sensitivity, specificity, PPV, and NPV for diagnosing esophageal perforation were 100.0%, 79.8%, 32.1%, and 100.0%, respectively, with CT and 77.8%, 98.9%, 87.5%, and 97.9% with fluoroscopic esophagography. Combining CT and fluoroscopic esophagography did not improve sensitivity, specificity, PPV, or NPV relative to using CT alone. The true-positive esophageal perforation rate was 8.7% for CT and 6.8% for fluoroscopic esophagography. When CT showed only pneumomediastinum (n = 51) or no pneumomediastinum (n = 14), the NPV of CT was 100.0%. CT with oral contrast material had a PPV of 38.5%, whereas CT without oral contrast material had a PPV of 26.7%. CONCLUSION. CT has a high NPV similar to that of fluoroscopic esophagography and has greater sensitivity than fluoroscopic esophagography for diagnosing suspected esophageal perforation. Fluoroscopic esophagrams do not provide additional information that changes clinical management beyond the information that CT provides. In ED patients with suspected esophageal perforation, CT with oral contrast material should be considered the initial imaging examination and can obviate fluoroscopic esophagography.

Acute Abdominal Pain Following Optical Colonoscopy: CT Findings and Clinical Considerations.

OBJECTIVE: Optical colonoscopy is a common procedure; more than 14 million are performed annually in the United States. Serious colonoscopy complications are uncommon, but they can be life-threatening if not quickly recognized. CONCLUSION: Optical colonoscopy complications that can be detected at CT include bowel perforation, postprocedural hemorrhage, postpolypectomy syndrome, splenic injury, appendicitis, and diverticulitis. Radiologist awareness of optical colonoscopy complications seen at CT is imperative for appropriate diagnosis and prompt patient management.

Nononcologic applications of diffusion-weighted imaging in the gastrointestinal system.

OBJECTIVE: The purpose of this article is to review infectious, inflammatory, and auto-immune-mediated processes in the gastrointestinal system where diffusion-weighted imaging can be helpful as well as pitfalls associated with its use. CONCLUSION: Diffusion-weighted imaging has become an important and widely used tool in abdominal and pelvic MRI, but it has been used primarily for oncologic applications. As more body MRI protocols are routinely including diffusion-weighted imaging, this sequence can be useful in evaluating an increasing number of nononcologic processes.

MR Enterography of the Ileoanal Pouch: Descriptive Radiologic Analysis With Endoscopic and Pathologic Correlation.

OBJECTIVE: The purpose of this study was to describe the MR enterography (MRE) appearance of inflammation of the ileoanal pouch after ileal pouch-anal anastomosis (IPAA) surgery and to correlate it with pouch endoscopic and histopathologic findings. MATERIALS AND METHODS: All MRE studies performed between October 1, 2007, and September 30, 2013, for patients who had previously undergone IPAA (n = 54) were retrieved. After review of medical records, the patients who underwent MRE, pouch endoscopy, and biopsy within 90 days (14 men, 14 women; mean age, 42.2 years; range, 24-67 years) were selected for inclusion in the study. Two blinded MRI radiologists in consensus retrospectively evaluated MRE studies for multiple MRI features. Two MRI scores were then calculated: an active and a composite inflammation score. A gastroenterologist retrospectively reviewed the pouch endoscopic images, and a pathologist reviewed the slides; both of these investigators were blinded. Both MRI scores were correlated with the pouch endoscopic and histopathologic findings. RESULTS: The composite MRI score had strong positive correlation with the endoscopic score (r = 0.61; p = 0.0005) but weak positive correlation with the histopathologic score (r = 0.31; p = 0.10, not statistically significant). The active inflammation MRI score had moderate positive correlation with the endoscopic score (r = 0.57; p = 0.0017) and weak positive correlation with the histopathologic score (r = 0.20; p = 0.31, not statistically significant). An MRI score ≥ 4 indicated the best results, with sensitivity of 86%, specificity of 79%, positive predictive value of 80%, negative predictive value of 85%, and accuracy of 82% for pouch inflammation. A positive likelihood ratio of 4.00 and negative likelihood ratio of 0.18 were obtained. CONCLUSION: In patients who have undergone IPAA surgery, the MRE findings strongly correlate with the pouch endoscopic findings with high sensitivity and positive predictive value for pouch inflammation. Therefore, MRE is a useful noninvasive test performed without ionizing radiation that can be used to evaluate patients with clinical symptoms and possibly alleviate the need for endoscopy in a select patient population.

Non-oncologic applications of diffusion-weighted imaging (DWI) in the genitourinary system.

Diffusion-weighted imaging (DWI) has become an increasingly used tool in abdominal and pelvic magnetic resonance imaging (MRI), primarily in the oncologic setting. DWI sequences are being added to routine MRI protocols at many institutions, and as its use has spread, more non-oncologic applications have been explored. The purpose of this article is to provide a review of DWI applications in inflammatory, infectious, autoimmune-mediated, and ischemic processes affecting the genitourinary system.

Graphic representation of clinical symptoms: a tool for improving detection of subtle fractures on foot radiographs.

OBJECTIVE: The purpose of this study was to assess changes in accuracy, degree of confidence, and evaluation time in radiography of subtle foot fractures when the text history is supplemented by a graphic indicating the site of pain. MATERIALS AND METHODS: Radiographs from 226 foot examinations (three views), including 126 examinations showing one subtle fracture (< 1-mm displacement) and 100 examinations with normal findings were selected. In the first interpretation session, only a text history was given for 112 examinations, and both text and a graphic indicating the site of pain for 114 examinations. Six months later, a graphic and text history were provided for the 112 cases interpreted without a graphic in the first session, and only text was provided for the other 114 cases. Seven radiologists evaluated the study sets. Sensitivity, specificity, degree of confidence (1-10 scale), and mean interpretation time in seconds were calculated. RESULTS: Use of a graphic increased overall sensitivity for any subtle fracture from 67% to 73% (p < 0.001), increased degree of confidence from 8.1 without a graphic to 8.4 with a graphic (p < 0.0001), and decreased the time for interpretation by 6%, from 53 seconds without a graphic to 50 seconds with a graphic (p = 0.006). Specificity changed from 93% without a graphic to 94% with a graphic (p = 0.33). Fractures of the third metatarsal were missed most frequently (74%); this percentage improved to 61% with use of a graphic. CONCLUSION: A graphic complements the text history by improving sensitivity, degree of confidence, and time for interpretation.

Improved short tau inversion recovery (iSTIR) for increased tumor conspicuity in the abdomen.

OBJECT: To develop an improved short tau inversion recovery (iSTIR) technique with simultaneous suppression of fat, blood vessels and fluid to increase tumor conspicuity in the abdomen for cancer screening. MATERIALS AND METHODS: An adiabatic spectrally selective inversion pulse was used for fat suppression to overcome the reduced signal to noise ratio associated with chemically non-selective inversion pulse of STIR. A motion-sensitizing driven equilibrium was used for blood vessel suppression and a dual-echo single-shot fast spin echo acquisition was used for fluid suppression. The technique was optimized on four normal subjects and later tested on five patients referred for metastatic tumor evaluation. RESULTS: A velocity encoding of 2 cm/s achieved effective blood suppression even in small vessels. Subtraction of two images (one with 60 ms and the other with 280 ms echo time) acquired in the same echo train achieved excellent fluid suppression (>70% reduction). Simultaneous suppression of fat, blood vessels and fluid improved the tumor conspicuity compared to corresponding fat-suppressed (STIR) image. CONCLUSION: This technique generated two complementary images from a single scan: one that is equivalent to a STIR image and the other that qualitatively resembles a diffusion-weighted image and may have potential for magnetic resonance imaging cancer screening.

Mimics of cancer in pregnancy.

Pregnancy is a remarkable time of pronounced growth and development of the fetus. Benign pathologies outside of the uterus, including those containing hormonally responsive tissue which undergo physiologic changes and other incidentally identified lesions, may mimic malignancy on clinical evaluation and imaging. A detailed history and physical exam, ultrasound and non-contrast magnetic resonance imaging features and comparison with prior imaging if available may help to narrow the list of potential differential diagnoses. Follow-up imaging in the postpartum period is often vital to confirm benignity and, in some cases, sampling to confirm the diagnosis is necessary. This review will cover the clinical, pathological and multimodality imaging features of numerous potential mimickers of cancer in the setting of pregnancy organized by organ systems. The goal is to better equip abdominal radiologists to accurately identify benign disease and help guide further imaging or follow-up recommendations to avoid unnecessarily aggressive intervention and improve patient care.

Corticomedullary differentiation on T1-Weighted MRI: comparison between cirrhotic and noncirrhotic patients.

PURPOSE: To determine whether corticomedullary differentiation (CMD) is increased in patients with cirrhosis compared to controls on axial T1-weighted magnetic resonance imaging (MRI). MATERIALS AND METHODS: Sixty patients with cirrhosis and 60 age-matched controls without renal disease underwent axial, T1-weighted in-phase gradient echo abdominal MRI. Each group of 60 was subdivided into three groups of 20 patients based on age: 18 to 45 years old; 45 to 65 years old; and greater than 65 years old. Signal intensity measurements of regions of interest obtained within the cortex and medulla of each kidney were recorded and the cortex-to-medulla contrast-to-noise ratio (CM-CNR) was calculated. Each patient's estimated glomerular filtration rate (eGFR) was recorded. RESULTS: Mean CM-CNR for both kidneys in cirrhotic patients (19.1 ± 10.5) was significantly higher than in controls (12.4 ± 5.0) (P < 0.0001). No significant correlation was observed between CM-CNR and eGFR levels for both cirrhotics and controls (P > 0.05). When stratified by age groups, no difference was observed in the mean CM-CNR for both kidneys among these three subgroups for both cirrhotics and controls (P > 0.05). CONCLUSION: Cirrhotic patients with normal renal function have an increased CMD compared to age-matched controls.

Incidental Splenic Findings on Cross-Sectional Imaging.

Incidental splenic focal findings are commonly encountered in clinical practice and frequently represent a diagnostic dilemma due to nonspecific imaging features. Most are benign, particularly in patients without a history of malignancy and without symptoms of fever, weight loss, or left upper quadrant or epigastric pain. Incidental malignant splenic processes are exceedingly rare. This article reviews imaging characteristics of incidental focal splenic findings, and proposes a practical approach for management of such findings, which can prevent unnecessary workup and its related drawbacks in clinical practice.

Dark cortical rim: an MRI feature of polycystic ovarian syndrome.

PURPOSE: To determine if the presence of a dark cortical rim around the ovary on magnetic resonance imaging (MRI) is associated with polycystic ovarian syndrome (PCOS). MATERIALS AND METHODS: This retrospective study included 52 PCOS patients with 98 total ovaries and 52 age-matched controls with 104 total ovaries. The ovaries were evaluated on MRI with at least two orthogonal views on T2-weighted sequences. Ovarian volume and follicular count per ovary were measured. Each ovary was also assessed for a dark cortical rim around the ovary on T2-weighted imaging which involved equal to or more than 50% of the ovarian circumference. The degree of rim continuity was classified as continuous if the rim involved greater than 75% of the ovarian circumference, discontinuous if 50-75% of the ovarian circumference was covered, or absent if less than 50% of the ovarian circumference was involved. The rim thickness was measured if present. T test and χ2 tests were performed to compare continuous and categorical variables, correspondingly, between cases and controls. ROC curves and area under the curve (AUC) were used to assess predictive performance and DeLong's paired test was used to compare AUCs. RESULTS: A higher percentage of PCOS patients exhibited a continuous cortical rim about the ovary (71%) and a lower percentage of an absent cortical rim (8%) compared to controls (25% and 37%, respectively) (p < 0.001). A continuous cortical ovarian rim has a sensitivity and specificity of 71% and 75%, respectively, for diagnosing PCOS. Mean cortical rim thickness is significantly higher in the PCOS group (1.4 mm) compared with controls (0.8 mm) (p < 0.001). Cortical rim thickness and presence of a continuous cortical rim are strongly correlated. Cortical rim thickness of 1.2 mm provides a sensitivity and specificity of 75% and 60%, correspondingly, for a diagnosis of PCOS. Cortical rim thickness combined with cortical rim continuity has an AUC of 0.77 for diagnosing PCOS, which is similar to conventional imaging features of ovarian volume and follicular count combined. CONCLUSION: A dark cortical rim around the ovary is an MRI feature that can be used to support a diagnosis of PCOS.

Prevalence of incidental pancreatic cysts in the adult population on MR imaging.

OBJECTIVES: The reporting of incidental pancreatic cystic lesions on cross-sectional imaging studies has dramatically increased over the last few years. The prevalence of incidental pancreatic cysts in the adult population, however, is unknown. The aim of our study was to determine the prevalence of incidentally detected pancreatic cysts in the adult population undergoing abdominal magnetic resonance (MR) imaging. METHODS: MR imaging examinations of 616 consecutive patients obtained between January 2001 and February 2002 were retrospectively reviewed by two radiologists and the following information was recorded: the total number of pancreatic cysts; the maximum diameter, location, and characteristics of the largest cyst; documentation of the cyst(s) within the radiology report; and characteristics of the cyst(s) at imaging follow-up. RESULTS: Incidental pancreatic cysts were present in 13.5% (83/616) of patients, with 60% of the cysts being solitary, and 88% of the cysts being simple. Largest cyst mean and median diameters were 7.4 mm (2-24 mm) and 6 mm, respectively. Both the prevalence of pancreatic cysts and the mean size of the largest cyst increased with age (P=0.007, r=0.893 and P=0.003, r=0.929, respectively). Only 31% (26/83) of incidental pancreatic cysts were documented in the radiology report. The mean size of reported pancreatic cysts was larger than those cysts that were not reported (P<0.001). CONCLUSIONS: The prevalence of incidentally detected pancreatic cysts on MR imaging is 13.5%, and increases with age. A majority of these cysts are not reported on MR imaging studies.

MR imaging of scrotal tumors and pseudotumors.

Magnetic resonance (MR) imaging is an important imaging technique in the evaluation of scrotal masses, providing a useful adjunct to ultrasonography (US). Although US is the modality of choice for initial evaluation of scrotal pathologic conditions because of its wide availability, low cost, and high sensitivity for detection of testicular and paratesticular disease processes, US findings may occasionally be inconclusive. MR imaging may provide additional information in these cases, often affecting patient management. This article reviews and illustrates the MR imaging features of solid extratesticular and intratesticular benign and malignant scrotal tumors, as well as nonneoplastic lesions that can mimic neoplasia. Normal scrotal MR anatomic features and optimal MR imaging technique are also presented.

Retroperitoneal cystic masses: magnetic resonance imaging features.

The objective of this review is to discuss the clinical and histopathologic features, MRI characteristics, and management options of retroperitoneal cystic masses. Radiologists should be familiar with the MR imaging characteristics of retroperitoneal cystic masses to allow for a refined differential diagnosis, assist with lesion management, and prevent unnecessary invasive procedures.

Imaging of the female urethra.

Female urethral pathology can be challenging to diagnose clinically due to non-specific symptoms. High-resolution MRI has become a powerful tool in the diagnosis of urethral lesions and staging of malignancy. Additionally, dynamic MRI, fluoroscopy or ultrasound can evaluate for pelvic floor prolapse and the effectiveness of surgical interventions. This article will review the imaging features of common benign and malignant conditions of the female urethra including diverticula, benign cystic and solid lesions, malignancy, surgical slings, and injection of bulking agents.

Differentiation of pancreatic head ductal adenocarcinoma from inflammatory pancreatic pseudomass by MR cholangio-pancreatography: utility of the duct-interrupted, corona, and attraction signs.

PURPOSE: To determine sensitivity and specificity of the "duct-interrupted," "corona," and "attraction" signs on MR cholangio-pancreatography (MRCP) in distinguishing pancreatic head ductal adenocarcinoma (PDAC) from inflammatory pancreatic pseudomass (IPP). MATERIALS AND METHODS: This study included 53 adults (33 men and 20 women, mean age, 55 years; range, 17-87 years) with a pancreatic head mass who underwent MRCP. Three blinded radiologists independently reviewed each MRCP exam and three signs were assessed: (1) the "duct-interrupted" sign, deemed positive for PDAC if the duct within the mass demonstrated complete interruption with upstream dilation; (2) the "corona" sign, considered positive for PDAC if dilated side-branches were located exclusively outside the mass; and (3) the "attraction" sign, deemed positive for IPP if the dilated common bile duct showed attraction and angulation towards the mass. Sensitivity, specificity, and positive and negative predictive values of the signs were calculated, as well as interobserver agreement. RESULTS: Out of 53 masses, 17 (32%) were PDAC and 36 (68%) were IPP. Sensitivity, specificity, and positive and negative predictive values of the "duct-interrupted" sign to differentiate between PDAC from IPP for the three readers were 29-53%, 89-95%, 56-82% and 73-81%, respectively (κ = 0.41); for the "corona" sign, they were 29-53%, 81-100%, 56-100%, and 75-78%, respectively (κ = 0.4), and for the "attraction" sign, they were 20-25%, 71-82%, 64-75%, and 31-34%, respectively (κ = 0.54). CONCLUSION: The "duct-interrupted" and "corona" MRCP signs have high specificity for diagnosing PDAC, while the "attraction" sign has good specificity for identifying IPP.

Localization of the appendix at MR imaging during pregnancy: utility of the cecal tilt angle.

PURPOSE: To determine whether the cecal tilt angle on sagittal magnetic resonance (MR) images in pregnant patients correlates with the location of the appendix and gestational age and whether the cecal tilt angle can help predict the location of the appendix. MATERIALS AND METHODS: This HIPAA-compliant retrospective study was approved by the institutional review board. Informed consent was waived. Of 146 consecutive pregnant patients suspected of having appendicitis (mean age, 29 years) who underwent MR imaging, 143 had MR images in which the appendix and cecum were identifiable in the sagittal plane. Two observers reviewed the MR images; findings were agreed upon by consensus. With use of sagittal single-shot fast spin-echo MR images, the cecal tilt angle was calculated as the angle between the imaging table and a line drawn between the cecal tip and the luminal center of the most proximal inflection point in the ascending colon. The location of the appendiceal base relative to the lumbosacral spine was recorded. Statistical analyses were performed by using Spearman and Pearson correlation coefficients to evaluate the relationship among gestational age, appendiceal base location, and cecal tilt angle. Receiver operating characteristic curve analysis was performed to assess the ability of the cecal tilt angle to help differentiate between a high and low appendiceal base level. RESULTS: Cecal tilt angles showed moderate correlation with appendiceal base levels (Spearman correlation coefficient, 0.44; P < .001) and poor correlation with gestational age (Pearson correlation coefficient, 0.25; P = .002). Regardless of gestational age, cecal tilt angles of at least 90 degrees were predictive of a high appendiceal base level with a specificity of 98% (95% confidence interval: 92%, 100%). CONCLUSION: The cecal tilt angle is useful for localizing the appendix in pregnant patients at MR imaging and helps predict the location of the appendix within the right upper quadrant of the abdomen with high specificity, irrespective of gestational age.