Diagnostic Accuracy of Unenhanced Computed Tomography for Evaluation of Acute Abdominal Pain in the Emergency Department.

Importance: Intravenous (IV) contrast medium is sometimes withheld due to risk of complication or lack of availability in patients undergoing computed tomography (CT) for abdominal pain. The risk from withholding contrast medium is understudied. Objective: To determine the diagnostic accuracy of unenhanced abdominopelvic CT using contemporaneous contrast-enhanced CT as the reference standard in emergency department (ED) patients with acute abdominal pain. Design, Setting, and Participants: This was an institutional review board-approved, multicenter retrospective diagnostic accuracy study of 201 consecutive adult ED patients who underwent dual-energy contrast-enhanced CT for the evaluation of acute abdominal pain from April 1, 2017, through April 22, 2017. Three blinded radiologists interpreted these scans to establish the reference standard by majority rule. IV and oral contrast media were then digitally subtracted using dual-energy techniques. Six different blinded radiologists from 3 institutions (3 specialist faculty and 3 residents) interpreted the resulting unenhanced CT examinations. Participants included a consecutive sample of ED patients with abdominal pain who underwent dual-energy CT. Exposure: Contrast-enhanced and virtual unenhanced CT derived from dual-energy CT. Main outcome: Diagnostic accuracy of unenhanced CT for primary (ie, principal cause[s] of pain) and actionable secondary (ie, incidental findings requiring management) diagnoses. The Gwet interrater agreement coefficient was calculated. Results: There were 201 included patients (female, 108; male, 93) with a mean age of 50.1 (SD, 20.9) years and mean BMI of 25.5 (SD, 5.4). Overall accuracy of unenhanced CT was 70% (faculty, 68% to 74%; residents, 69% to 70%). Faculty had higher accuracy than residents for primary diagnoses (82% vs 76%; adjusted odds ratio [OR], 1.83; 95% CI, 1.26-2.67; P = .002) but lower accuracy for actionable secondary diagnoses (87% vs 90%; OR, 0.57; 95% CI, 0.35-0.93; P < .001). This was because faculty made fewer false-negative primary diagnoses (38% vs 62%; OR, 0.23; 95% CI, 0.13-0.41; P < .001) but more false-positive actionable secondary diagnoses (63% vs 37%; OR, 2.11, 95% CI, 1.26-3.54; P = .01). False-negative (19%) and false-positive (14%) results were common. Interrater agreement for overall accuracy was moderate (Gwet agreement coefficient, 0.58). Conclusion: Unenhanced CT was approximately 30% less accurate than contrast-enhanced CT for evaluating abdominal pain in the ED. This should be balanced with the risk of administering contrast material to patients with risk factors for kidney injury or hypersensitivity reaction.

Association of Patient and Imaging-Related Factors With False Negative MRI-Targeted Prostate Biopsies of Suspicious PI-RADS 4 and 5 Lesions.

OBJECTIVE: To investigate specific imaging and patient-related factors associated with a false negative (FN) MRI-targeted prostate fusion biopsies (TBx) of suspicious MRI lesions. METHODS: Retrospective study of men with PI-RADS 4 or 5 lesions November, 2015-December 2020 with TBx and systematic biopsy (SBx) performed. Only FN and true positive (TP) targeted lesions were included. FN biopsy was defined as a negative TBx with a positive systematic core in the ROI or perilesional sextant. Logistic regression was used to determine the association of patient and imaging-specific factors with the probability of a FN TBx. RESULTS: 361 PI-RADS 4 or 5 lesions in 304 patients, including 67 FN (19%) and 294 TP (81%) were included. There was a significant inverse association between lesion size (OR: 0.94, P-value: .02), presence of a suspicious DRE (OR: 0.36, P-value: .02) and PSA density (OR: 0.01, P-value: .004) on the probability of obtaining a FN TBx. There was no association between age, biopsy indication, use of an enema before MRI, prostate size, or discrepant US and MRI segmentation volumes on the probability of a FN TBx. CONCLUSION: In this cohort, SBx detected 19% of csPCa missed on TBx. Smaller PI-RADS 4/5 lesions, lower PSAD values, and a normal DRE were all associated with an increased probability of a FN TBx.

Tennis overuse injuries in the upper extremity.

OBJECTIVE: Tennis is a popular sport with high levels of participation. This article aims to describe how upper extremity overuse injuries occur in relation to tennis biomechanics and to review their imaging characteristics and implications for management. In particular, we will review the imaging patterns of internal impingement, scapular dyskinesis, lateral and medial epicondylitis, ulnar collateral ligament insufficiency, valgus extension overload, capitellar osteochondritis dissecans, extensor carpi ulnaris tendinosis and instability, tenosynovitis, triangular fibrocartilage complex injuries, and carpal stress injuries. CONCLUSION: Tennis is a complex and physically demanding sport with a wide range of associated injuries. Repetitive overloading commonly leads to injuries of the upper extremity. An understanding of the underlying mechanisms of injury and knowledge of these injury patterns will aid the radiologist in generating the correct diagnosis in both the professional and recreational tennis athlete.

Case of urethral duplication seen by voiding urosonography.

A 3-month-old premature male infant with imperforate anus and hypospadias underwent contrast-enhanced voiding urosonography (ceVUS) followed by voiding cystourethrography (VCUG). Images from the ceVUS demonstrated a distinct linearity arising dorsally from the posterior urethra that partially opacified with contrast. VCUG confirmed a urethral duplication. To our knowledge, this exceedingly rare anomaly has yet to be reported by ceVUS.

Moyamoya Syndrome in a Child with Neurofibromatosis Type 1: Magnetic Resonance Imaging as a Tool for Clinical Decision Making.

Moyamoya syndrome is a rare cerebrovasculopathy of unknown etiology which is associated with multiple risk factors. Moyamoya was first discovered in Japan and is reported to have an increased prevalence in the Japanese population. The term "Moyamoya" translates into "puff of smoke" and is named after the finding of the collateral cerebral vasculature that develops secondary to occlusion of an internal carotid artery at the entrance into the circle of Willis. This collateral vasculature characterizes the disease. Moyamoya should be included in the differential diagnosis in the pediatric population when a patient presents with stroke or stroke-like symptoms. Diagnosis can be made with catheter angiogram or magnetic resonance angiogram. Recent use of magnetic resonance perfusion imaging has been shown to be useful in clinical decision making while assessing the need for revascularization surgery. We present the case of a 15-year-old with comorbid psychiatric illness, neurofibromatosis type I with brainstem glioma, and Moyamoya syndrome. Considering our patient`s complex medical history of psychiatric illness and previously diagnosed neurofibromatosis, magnetic resonance imaging (MRI) with magnetic resonance angiogram (MRA) and magnetic resonance perfusion proved instrumental in helping rule out the progression of arteriopathy as the cause of his worsening seizures and behavior. In our patient, it was determined that the relative perfusion for each hemisphere of the patient's brain quantitatively lacked significant differences and he was therefore not a candidate for surgical revascularization. These modalities proved instrumental in surgical decision-making and clinical management of the patient.

Dermoid of the oral cavity: case report with histopathology correlation and review of literature.

Dermoid cysts are rare masses of the oral cavity derived from ectodermal elements. These are benign, slow-growing tumors that are typically asymptomatic but cause complications of inflammation or dysphagia, dystonia, and airway encroachment due to mass effects. We report the case of a 17 year old female with a painless mass in the left side of the oral cavity. Ultrasound findings demonstrated non-specific findings of a cystic lesion, and definite diagnosis was made with contrast-enhanced CT and intraoperatively with pathologic confirmation. This retrospective report highlights the challenges in evaluating masses of the oral cavity with imaging and provides a comprehensive discussion on imaging of oral masses on various imaging modalities to guide diagnosis and management.