Expanding Role of Dual-Energy CT for Genitourinary Tract Assessment in the Emergency Department, From the AJR Special Series on Emergency Radiology.

Among explored applications of dual-energy CT (DECT) in the abdomen and pelvis, the genitourinary (GU) tract represents an area where accumulated evidence has established the role of DECT to provide useful information that may change management. This review discusses established applications of DECT for GU tract assessment in the emergency department (ED) setting, including characterization of renal stones, evaluation of traumatic injuries and hemorrhage, and characterization of incidental renal and adrenal findings. Use of DECT for such applications can reduce the need for additional multiphase CT or MRI examinations and reduce follow-up imaging recommendations. Emerging applications are also highlighted, including use of low-energy virtual monoenergetic images (VMIs) to improve image quality and potentially reduce contrast media doses and use of high-energy VMIs to mitigate renal mass pseudoenhancement. Finally, implementation of DECT into busy ED radiology practices is presented, weighing the trade-off of additional image acquisition, processing time, and interpretation time against potential additional useful clinical information. Automatic generation of DECT-derived images with direct PACS transfer can facilitate radiologists' adoption of DECT in busy ED environments and minimize impact on interpretation times. Using the described approaches, radiologists can apply DECT technology to improve the quality and efficiency of care in the ED.

Sarcopenia Is Associated With Increased Mortality in Patients With Necrotizing Soft Tissue Infections.

INTRODUCTION: Necrotizing soft tissue infections (NSTIs) are surgical emergencies associated with high morbidity and mortality. Identifying risk factors for poor outcome is a critical part of preoperative decision-making and counseling. Sarcopenia, the loss of lean muscle mass, has been associated with an increased risk of mortality and can be measured using cross-sectional imaging. Our aim was to determine the impact of sarcopenia on mortality in patients with NSTI. We hypothesized that sarcopenia would be associated with an increased risk of mortality in patients with NSTI. METHODS: This is a retrospective cohort study of NSTI patients admitted from 1995 to 2015 to two academic institutions. Operative and pathology reports were reviewed to confirm the diagnosis in all cases. Average bilateral psoas muscle cross-sectional area at L4, normalized for height (Total Psoas Index [TPI]), was calculated using computed tomography (CT). Sarcopenia was defined as TPI in the lowest sex-specific quartile. Primary outcome was in-hospital mortality. Multivariate logistic regression was performed to assess the association between sarcopenia and in-hospital mortality. RESULTS: There were 115 patients with preoperative imaging, 61% male and a median age of 57 y interquartile range (IQR 46.6-67.0). Overall in-hospital mortality was 12.1%. There was no significant difference in sex, body mass index (BMI), comorbidities and American Society of Anesthesiologists classification (Table 1). After multivariate analysis, sarcopenia was independently associated with increased in-hospital mortality (Odds ratio, 3.5; 95% Confidence Interval [CI], 1.05-11.8). CONCLUSIONS: Sarcopenia is associated with increased risk of in-hospital mortality in patients with NSTIs. Sarcopenia identifies patients with higher likelihood of poor outcomes, which can possibly help surgeons in counseling their patients and families.

CT imaging findings of complications of optical colonoscopy.

Colonoscopy is one of the most commonly performed endoscopic procedures and remains the most commonly used screening modality method for colorectal cancer (CRC) screening in the USA. Although serious complications of fiberoptic colonoscopy are uncommon due to technical advances, due to increasing number of colonoscopy procedures, post-procedural complications are not uncommonly encountered in the routine clinical practice. Also, as some of the post-colonoscopy complications are life threatening, it is important to diagnose them early so that timely treatment measures can be taken to decrease mortality and morbidity. In this review, we present a case-based illustration of the utility of CT to detect complications of colonoscopy including bowel perforation, hemorrhage, splenic injury, and postpolypectomy syndrome.

Dual energy CT in clinical routine: how it works and how it adds value.

Dual energy computed tomography (DECT), also known as spectral CT, refers to advanced CT technology that separately acquires high and low energy X-ray data to enable material characterization applications for substances that exhibit different energy-dependent x-ray absorption behavior. DECT supports a variety of post-processing applications that add value in routine clinical CT imaging, including material selective and virtual non-contrast images using two- and three-material decomposition algorithms, virtual monoenergetic imaging, and other material characterization techniques. Following a review of acquisition and post-processing techniques, we present a case-based approach to highlight the added value of DECT in common clinical scenarios. These scenarios include improved lesion detection, improved lesion characterization, improved ease of interpretation, improved prognostication, inherently more robust imaging protocols to account for unexpected pathology or suboptimal contrast opacification, length of stay reduction, reduced utilization by avoiding unnecessary follow-up examinations, and radiation dose reduction. A brief discussion of post-processing workflow approaches, challenges, and solutions is also included.

Improved Appropriateness of Advanced Diagnostic Imaging After Implementation of Clinical Decision Support Mechanism.

The Protecting Access to Medicare Act (PAMA) mandates clinical decision support mechanism (CDSM) consultation for all advanced imaging. There are a growing number of studies examining the association of CDSM use with imaging appropriateness, but a paucity of multicenter data. This observational study evaluates the association between changes in advanced imaging appropriateness scores with increasing provider exposure to CDSM. Each provider's first 200 consecutive anonymized requisitions for advanced imaging (CT, MRI, ultrasound, nuclear medicine) using a single CDSM (CareSelect, Change Healthcare) between January 1, 2017 and December 31, 2019 were collected from 288 US institutions. Changes in imaging requisition proportions among four appropriateness categories ("usually appropriate" [green], "may be appropriate" [yellow], "usually not appropriate" [red], and unmapped [gray]) were evaluated in relation to the chronological order of the requisition for each provider and total provider exposure to CDSM using logistic regression fits and Wald tests. The number of providers and requisitions included was 244,158 and 7,345,437, respectively. For 10,123 providers with ≥ 200 requisitions (2,024,600 total requisitions), the fraction of green, yellow, and red requisitions among the last 10 requisitions changed by +3.0% (95% confidence interval +2.6% to +3.4%), -0.8% (95% CI -0.5% to -1.1%), and -3.0% (95% CI 3.3% to -2.7%) in comparison with the first 10, respectively. Providers with > 190 requisitions had 8.5% (95% CI 6.3% to 10.7%) more green requisitions, 2.3% (0.7% to 3.9%) fewer yellow requisitions, and 0.5% (95% CI -1.0% to 2.0%) fewer red (not statistically significant) requisitions relative to providers with ≤ 10 requisitions. Increasing provider exposure to CDSM is associated with improved appropriateness scores for advanced imaging requisitions.

Bone Marrow Edema at Dual-Energy CT: A Game Changer in the Emergency Department.

Dual-energy CT is increasingly being used in the emergency department to help diagnose acute conditions. Its applications include demonstrating bone marrow edema (BME) seen in the setting of occult fractures and other acute conditions. Dual-energy CT acquires data with two different x-ray energy spectra and is able to help differentiate materials on the basis of their differential energy-dependent x-ray absorption behaviors. Virtual noncalcium (VNCa) techniques can be used to suppress the high attenuation of trabecular bone, thus enabling visualization of subtle changes in the underlying attenuation of the bone marrow. Visualization of BME can be used to identify occult or mildly displaced fractures, pathologic fractures, metastases, and some less commonly visualized conditions such as ligamentous injuries or inflammatory arthritis. The authors' major focus is use of dual-energy CT as a diagnostic modality in the setting of trauma and to depict subtle or occult fractures. The authors also provide some scenarios in which dual-energy CT is used to help diagnose other acute conditions. The causes and pathophysiology of BME are reviewed. Dual-energy CT image acquisition and VNCa postprocessing techniques are also discussed, along with their applications in emergency settings. The authors present potential pitfalls and limitations of these techniques and their possible solutions.©RSNA, 2020.

Dual-energy CT for routine imaging of the abdomen and pelvis: radiation dose and image quality.

PURPOSE: To assess the radiation dose and image quality of routine dual energy CT (DECT) of the abdomen and pelvis performed in the emergency department setting, compared with single energy CT (SECT). MATERIALS AND METHODS: Seventy-five consecutive routine contrast-enhanced SECT scans of the abdomen and pelvis meeting inclusion criteria were compared with 75 routine contrast-enhanced DECT scans matched by size and patient weight (within 10 lbs), performed on the same dual-source DECT scanner. Cohorts were compared in terms of radiation dose metrics of CT dose index (CTDIvol) and dose length product (DLP), objective measurements of image quality (signal, noise, and signal-to-noise ratio of a variety of anatomical landmarks), and subjective measurements of image quality scored by two emergency radiologists. RESULTS: Demographics and patient size were not statistically different between DECT and SECT cohorts. Both average scans CTDIvol and DLP were significantly lower with DECT than with SECT. Average scan CTDIvol for SECT was 14.7 mGy (± 6.6) and for DECT was 10.9 mGy (± 3.8) (p < 0.0001). Average scan DLP for SECT was 681.5 mGy cm (± 339.3) and for DECT was 534.8 mGy cm (± 201.9) (p < 0.0001). For objective image quality metrics, for all structures measured, noise was significantly lower and SNR was significantly higher with DECT compared with SECT. For subjective image quality, for both readers, there was no significant difference between SECT and DECT in subjective image quality for soft tissues and vascular structures, or for subjective image noise. CONCLUSIONS: DECT was performed with decreased radiation dose when compared with SECT, demonstrated improved objective measurements of image quality, and equivalent subjective image quality.

Multidetector CT of Laryngeal Injuries: Principles of Injury Recognition.

Blunt laryngeal trauma is associated with high morbidity and mortality. However, owing to their relatively rare occurrence, laryngeal injuries may be missed or underdiagnosed. Even subtle abnormalities at multidetector CT may correspond to significant functional abnormalities. It is important to understand normal CT laryngeal anatomy and develop a systematic review of the cervical soft tissues and laryngeal skeleton in patients who undergo screening CT cervical spine or other neck examinations in the setting of trauma, such as CT angiography. Multidetector CT findings of the normal larynx are reviewed, and blunt laryngeal injuries including soft-tissue edema, hematoma, mucosal lacerations, cartilage fracture, cricoarytenoid dislocation, and vocal fold paralysis are presented. The radiologist plays an important role in diagnosis and may be the first to identify laryngeal injuries that are not evident at physical examination. This article reviews normal laryngeal anatomy, presents various blunt laryngeal injuries at multidetector CT with case examples, discusses the role of multidetector CT in acute management, and describes pitfalls of diagnosis. ©RSNA, 2019.

Virtual monoenergetic dual-energy CT for evaluation of hepatic and splenic lacerations.

PURPOSE: To evaluate the utility of virtual monoenergetic imaging in assessing hepatic and splenic lacerations and to determine the optimal energy level to maximize injury contrast-to-noise ratio. METHODS: We retrospectively examined 49 contrast-enhanced abdominal CT studies performed on a dual-source dual-energy CT (DECT) scanner with reported liver and/or splenic lacerations. All studies included portal venous phase imaging acquired simultaneously at low (80 or 100 kVp) and high (140 kVp with tin filtration) energy levels. Conventional 120 kVp-equivalent images were generated for routine review by blending the low and high energy acquisitions. Virtual monoenergetic reconstructions were retrospectively generated in 10 keV increments from 40 to 90 keV. Liver or splenic laceration attenuation, background parenchymal attenuation, and noise were measured on each set of monoenergetic and conventional images. Injury-to-parenchyma contrast and contrast-to-noise ratios (CNR) were calculated. Differences between CNR of monoenergetic series and conventional images were assessed with a paired t test. RESULTS: Liver laceration was identified in 28 patients, and splenic laceration in 22 patients. Background noise was lower at higher monoenergetic levels, with the lowest noise seen at 90 keV, less than that of conventional images (stddev 8.0 for 90 keV and 8.5 for conventional based on noise of uninjured liver/spleen parenchyma, p < 0.001). For both liver and splenic lacerations, injury-to-parenchyma contrast was greater at lower monoenergetic levels, with maximum at 40 keV. Contrast at 40-70 keV was significantly greater than that of conventional images (p < 0.001). Injury-to parenchyma CNR was also greater at 40-70 keV than that of conventional images and with statistical significance. CNR was highest at 40 keV for both liver (6.5 for 40 keV and 5.4 for conventional, p < 0.001) and splenic lacerations (7.5 vs. 5.8, p < 0.001). CONCLUSIONS: DECT virtual monoenergetic imaging at low keV improves injury-to-parenchyma CNR of hepatic and splenic lacerations compared with traditional polyenergetic reconstructions. Specially, the optimal energy level for assessing both was 40 keV.

Dual-Energy CT for Abdominal and Pelvic Trauma.

Computed tomography (CT) is key to the assessment of hemodynamically stable patients with blunt or penetrating trauma to the abdomen and pelvis. Dual-energy (DE) CT is a technology that allows acquisition of data at both high and low kilovolt peaks, allowing materials that have different x-ray absorption behaviors as a function of kilovolt peak (such as iodine) to be differentiated and quantified. DE CT has a variety of postprocessing applications that may be helpful in abdominal and pelvic trauma, including iodine-selective imaging, virtual monenergetic imaging, and virtual noncalcium imaging. Both iodine-selective imaging and virtual monoenergetic imaging can increase the conspicuity of traumatic solid-organ and hollow visceral injuries, making injuries easier to detect and categorize. Iodine-selective imaging, through the use of iodine maps and virtual noncontrast images, can assist in the evaluation of active contrast extravasation. Virtual noncalcium images can unmask bone marrow edema, improving detection of subtle fractures. The purpose of this review article is to familiarize radiologists with the basic physics and technical principles of DE CT, common postprocessing techniques, and the potential added value of DE CT in patients with abdominal and pelvic trauma. The technical limitations of DE CT are also reviewed, as are diagnostic pitfalls and common challenges in interpretation. ©RSNA, 2018.

Multimodality Imaging, including Dual-Energy CT, in the Evaluation of Gallbladder Disease.

Imaging of the gallbladder has a key role in the examination of patients with abdominal pain-especially pain localized to the right upper quadrant. Pathologic conditions that affect the gallbladder include cholelithiasis and associated complications such as acute and chronic cholecystitis, choledocholithiasis, gallstone pancreatitis, and cancer. Modalities used to image the gallbladder include ultrasonography (US), computed tomography (CT), magnetic resonance (MR) imaging, and nuclear scintigraphy. US is the primary imaging modality used to evaluate entities suspected of being gallbladder disease, as it is both sensitive and specific for demonstrating gallstones, biliary duct dilatation, and inflammatory features. However, CT is often the first imaging examination performed in patients who present to the emergency department with acute abdominal pain. Because the CT appearance of gallstones is variable, depending on the composition of the stone, pattern of calcification, and presence of gas, gallstones and other gallbladder conditions can be difficult to detect at conventional multidetector CT, with which data are acquired by using a single x-ray energy spectrum. Dual-energy CT, with which one takes advantage of the material-dependent x-ray absorption behavior of concurrently acquired high- and low-kilovolt-peak data, can add value by increasing the conspicuity of noncalcified gallstones and improving the detection of acute cholecystitis and gallbladder malignancy. In addition, MR cholangiopancreatography can be helpful for assessing choledocholithiasis and complicated biliary duct disease. ©RSNA, 2018.

Imaging of Acute Conditions of the Perineum.

A wide range of acute conditions can affect the perineum, from self-limited disease to conditions that are potentially life threatening or contribute to substantial patient morbidity if not promptly diagnosed and appropriately treated. Imaging is essential in the clinical management of perineal disease because it allows accurate anatomic localization of the origin and extent of the disease to be determined. Familiarity with complex perineal anatomy, appropriate use of imaging modalities, and the spectrum of imaging findings seen in acute perineal conditions is crucial for radiologists to make a rapid and accurate diagnosis. Various imaging modalities are available to evaluate acute perineal conditions, each with their own advantages and disadvantages. Computed tomography is used most commonly in the acute care setting because of its widespread availability and rapid image acquisition. Ultrasonography could be used to evaluate superficial and palpable abnormalities and is especially helpful for diagnosis of genital injuries. Magnetic resonance (MR) imaging exhibits superior tissue contrast resolution, provides excellent characterization of conditions, and lacks ionizing radiation. Its role is increasing in the acute care setting; however, MR imaging is not always readily available and is currently reserved for use as a problem-solving technique. Retrograde urethrography is the modality of choice for evaluating traumatic urethral injury. ©RSNA, 2018.

Imaging of acute and emergent genitourinary conditions: what the radiologist needs to know.

OBJECTIVE: Acute and emergent genitourinary conditions require accurate and rapid diagnosis to minimize patient morbidity and mortality. CONCLUSION: Radiologists' familiarity with the various conditions of the urinary system and of the male and female reproductive organs is important given the widespread use of imaging for the diagnosis of common clinical entities presenting to the emergency department.

A quantitative comparison of noise reduction across five commercial (hybrid and model-based) iterative reconstruction techniques: an anthropomorphic phantom study.

OBJECTIVE. The objective of our study was to compare the performance of three hybrid iterative reconstruction techniques (IRTs) (ASiR, iDose4, SAFIRE) and their respective strengths for image noise reduction on low-dose CT examinations using filtered back projection (FBP) as the standard reference. Also, we compared the performance of these three hybrid IRTs with two model-based IRTs (Veo and IMR) for image noise reduction on low-dose examinations. MATERIALS AND METHODS. An anthropomorphic abdomen phantom was scanned at 100 and 120 kVp and different tube current-exposure time products (25-100 mAs) on three CT systems (for ASiR and Veo, Discovery CT750 HD; for iDose4 and IMR, Brilliance iCT; and for SAFIRE, Somatom Definition Flash). Images were reconstructed using FBP and using IRTs at various strengths. Nine noise measurements (mean ROI size, 423 mm(2)) on extracolonic fat for the different strengths of IRTs were recorded and compared with FBP using ANOVA. Radiation dose, which was measured as the volume CT dose index and dose-length product, was also compared. RESULTS. There were no significant differences in radiation dose and image noise among the scanners when FBP was used (p > 0.05). Gradual image noise reduction was observed with each increasing increment of hybrid IRT strength, with a maximum noise suppression of approximately 50% (48.2-53.9%). Similar noise reduction was achieved on the scanners by applying specific hybrid IRT strengths. Maximum noise reduction was higher on model-based IRTs (68.3-81.1%) than hybrid IRTs (48.2-53.9%) (p < 0.05). CONCLUSION. When constant scanning parameters are used, radiation dose and image noise on FBP are similar for CT scanners made by different manufacturers. Significant image noise reduction is achieved on low-dose CT examinations rendered with IRTs. The image noise on various scanners can be matched by applying specific hybrid IRT strengths. Model-based IRTs attain substantially higher noise reduction than hybrid IRTs irrespective of the radiation dose.

Evaluation of Acute Abdominal Pain in the Emergency Setting Using Computed Tomography Without Oral Contrast in Patients With Body Mass Index Greater Than 25.

PURPOSE: To evaluate the rate of delayed or missed diagnoses and need for additional computed tomography (CT) imaging in emergency department patients with abdominal pain who are imaged without oral contrast. MATERIALS AND METHODS: The institutional review board approved this Health Insurance Portability and Accountability Act-compliant retrospective study; informed consent was waived. All consecutive adult patients with body mass index greater than 25 undergoing a CT abdomen/pelvis with intravenous contrast and without oral contrast with nontraumatic acute abdominal pain during a 16-month period at our academic tertiary care center were included. Medical records were reviewed, imaging findings on admission CT, use of repeat CT examinations within 4 weeks of the original examination, and clinical outcomes were recorded. In patients undergoing repeat imaging, an investigator determined whether repeat imaging was influenced by the lack of oral contrast on the original examination. As the most common cause of bowel-related positive CT scans, an analysis of acute appendicitis was performed. RESULTS: Of the 1992 patients included in this study, 4 patients (0.2%) underwent repeat CT studies directly related to the absence of oral contrast on the original examination. Of the 1992 CT scans, 1193(59.8%) were interpreted as negative, none of which required surgery or direct intervention. In patients with acute appendicitis, there was a sensitivity of CT in this patient population of 100% with a specificity of 99.5%. CONCLUSIONS: In patients with body mass index greater than 25 presenting to the ED with acute abdominal pain, CT examinations can be acquired without oral contrast without compromising the clinical efficacy of CT.

The utility of CT for predicting bile leaks in hepatic trauma.

The purpose of this study was to determine the efficacy of CT to predict the development of bile leaks in hepatic trauma. This HIPAA-compliant retrospective study was IRB approved and consent was waived. All patients who sustained hepatic trauma between January 1, 2006, and January 31, 2012, and who underwent CT and hepatobiliary scans during the same hospital admission were included. One hundred and thirty-two patients met the inclusion criteria. Comparison between the presence of biliary injury relative to American Association for the Surgery of Trauma (AAST) hepatic injury grade and mean distance of the hepatic laceration to the inferior vena cava (IVC) was made. The ability of free fluid to predict bile injury was analyzed. Forty-one (31 %) of the 132 patients had positive hepatobiliary scans. Of these 41 patients, seven (17 %) sustained low-grade and 34 (83 %) sustained high-grade hepatic injury compared with the 37 (41 %) low-grade and 54 (59 %) high-grade hepatic injuries in the negative hepatobiliary scan group. The mean distance to the IVC was 2.4 cm (SD 2.9 cm) and 3.6 cm (SD 3.3 cm) in patients with and without bile leaks, respectively. A statistically significant difference in the proportion of high-grade injuries and the mean distance from the IVC between the two groups was identified. The presence of free fluid on CT is sensitive, but not specific, for detecting a bile leak. CT findings, including AAST liver injury grade and location of the liver laceration, are able to predict which patients are at risk for developing bile leaks as seen on hepatobiliary scintigraphy, whereas the presence of free fluid is not.

Active hemorrhage and vascular injuries in splenic trauma: utility of the arterial phase in multidetector CT.

PURPOSE: To determine whether the addition of arterial phase computed tomography (CT) to the standard combination of portal venous and delayed phase imaging increases sensitivity in the diagnosis of active hemorrhage and/or contained vascular injuries in patients with splenic trauma. MATERIALS AND METHODS: The institutional review board approved this HIPAA-compliant retrospective study; the requirement to obtain informed consent was waived. The study included all patients aged 15 years and older who sustained a splenic injury from blunt or penetrating trauma and who underwent CT in the arterial and portal venous phases of image acquisition during a 74-month period (September 2005 to November 2011). CT scans were reviewed by three radiologists, and a consensus interpretation was made to classify the splenic injuries according to the American Association for the Surgery of Trauma splenic injury scale. One radiologist independently recorded the presence of contained vascular injuries or active hemorrhage and the phase or phases at which these lesions were seen. Clinical outcome was assessed by reviewing medical records. The relationship between imaging findings and clinical management was assessed with the Fisher exact test. RESULTS: One hundred forty-seven patients met the inclusion criteria; 32 patients (22%) had active hemorrhage and 22 (15%) had several contained vascular injuries. In 13 of the 22 patients with contained injuries, the vascular lesion was visualized only at the arterial phase of image acquisition; the other nine contained vascular injuries were seen at all phases. Surgery or embolization was performed in 11 of the 22 patients with contained vascular injury. CONCLUSION: The arterial phase of image acquisition improves detection of traumatic contained splenic vascular injuries and should be considered to optimize detection of splenic injuries in trauma with CT.

Approaches, advantages, and challenges to photon counting detector and multi-energy CT.

Photon counting detector CT (PCD-CT) is the newest major development in CT technology and has been commercially available since 2021. It offers major technological advantages over current standard-of-care energy integrating detector CT (EID-CT) including improved spatial resolution, improved iodine contrast to noise ratio, multi-energy imaging, and reduced noise. This article serves as a foundational basis to the technical approaches and concepts of PCD-CT technology with primary emphasis on detector technology in direct comparison to EID-CT. The article also addresses current technological challenges to PCD-CT with particular attention to cross talk and its causes (e.g., Compton scattering, fluorescence, charge sharing, K-escape) as well as pile-up.

ACR Appropriateness Criteria® Hydronephrosis on Prior Imaging-Unknown Cause.

Initial imaging evaluation of hydronephrosis of unknown etiology is a complex subject and is dependent on clinical context. In asymptomatic patients, it is often best conducted via CT urography (CTU) without and with contrast, MR urography (MRU) without and with contrast, or scintigraphic evaluation with mercaptoacetyltriglycine (MAG3) imaging. For symptomatic patients, CTU without and with contrast, MRU without and with contrast, MAG3 scintigraphy, or ultrasound of the kidneys and bladder with Doppler imaging are all viable initial imaging studies. In asymptomatic pregnant patients, nonionizing imaging with US of the kidneys and bladder with Doppler imaging is preferred. Similarly, in symptomatic pregnant patients, US of the kidneys and bladder with Doppler imaging or MRU without contrast is the imaging study of choice, as both ionizing radiation and gadolinium contrast are avoided in pregnancy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ACR Appropriateness Criteria® Acute Pelvic Pain in the Reproductive Age Group: 2023 Update.

This review focuses on the initial imaging in the reproductive age adult population with acute pelvic pain, including patients with positive and negative beta-human chorionic gonadotropin (ß-hCG) levels with suspected gynecological and nongynecological etiology. For all patients, a combination of transabdominal and transvaginal pelvic ultrasound with Doppler is usually appropriate as an initial imaging study. If nongynecological etiology in patients with negative ß-hCG is suspected, then CT of the abdomen and pelvis with or without contrast is also usually appropriate. In patients with positive ß-hCG and suspected nongynecological etiology, CT of the abdomen and pelvis with contrast and MRI of the abdomen and pelvis without contrast may be appropriate. In patients with negative ß-hCG and suspected gynecological etiology, CT of the abdomen and pelvis with contrast, MRI of pelvis without contrast, or MRI of pelvis with and without contrast may be appropriate. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.