Suzanne T. Chong

Imaging of pregnant and lactating patients: part 1, evidence-based review and recommendations.

OBJECTIVE The objectives of this article are to discuss the current evidence-based recommendations regarding radiation dose concerns, the use of iodinated and gadolinium-based contrast agents, and the comparative advantages of multimodality imaging (ultrasound, CT, and MRI) during pregnancy and lactation. We also discuss the use of imaging to evaluate pregnant trauma patients. CONCLUSION Maternal and fetal radiation exposure and dose are affected by gestational age, anatomic site, modality, and technique. The use of iodinated and gadolinium-based contrast agents during pregnancy and lactation has not been well studied in human subjects. Imaging should be used to evaluate pregnant trauma patients only when the benefits outweigh the risks.

MDCT and Radiography of Wrist Fractures: Radiographic Sensitivity and Fracture Patterns

OBJECTIVE The purpose of our study was to determine which wrist fractures are not prospectively diagnosed at radiography using CT as a gold standard and to identify specific fracture patterns. MATERIALS AND METHODS Through a search of radiology records from January 1 to December 31, 2005, 103 consecutive patients were identified as having radiographic and CT examinations of the wrist. After excluding incomplete or nondiagnostic examinations and those with a greater than 6-week interval between imaging studies, the final study group consisted of 61 wrist examinations in 60 patients. Two musculoskeletal radiologists and one emergency radiologist blindly reviewed CT examinations, and each bone (scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, hamate, metacarpals, distal radius, distal ulna) was categorized as normal or fractured, with agreement reached by consensus. Each prospective radiographic report was categorized as either normal or fracture/equivocal for each osseous structure. Results were compared using the chi-square and Fishers exact tests. RESULTS In the proximal carpal row, lunate and triquetrum fractures were often radiographically occult (0% and 20%, respectively, detected at radiography); whereas in the distal carpal row, trapezoid, capitate, and hamate fractures were often occult (0%, 0%, and 40% detected at radiography, respectively). Hamate fractures were significantly associated with metacarpal fractures, and distal radius fractures were associated with scaphoid and ulna fractures. CONCLUSION Thirty percent of wrist fractures were not prospectively diagnosed on radiography, suggesting that CT should be considered after a negative radiographic finding if clinically warranted. The location of a dorsal scaphoid avulsion fracture emphasizes the need for specific radiographic views or cross-sectional imaging for diagnosis.

Cross-Sectional Examination Interpretation Discrepancies Between On-Call Diagnostic Radiology Residents and Subspecialty Faculty Radiologists: Analysis by Imaging Modality and Subspecialty

PURPOSE The aim of this study was to identify the rate of discrepancies between radiology residents and faculty radiologists at an academic hospital and to determine the distribution across subspecialties and modalities, specifically CT, MR, and ultrasound. METHODS Consecutive CT, MR, and ultrasound preliminary interpretations rendered by on-call second-year through fourth-year radiology residents for 9 months on emergency department patients, inpatients, and urgent outpatients formed the study population. All preliminary interpretations were graded using a modified RADPEER(®) system (scores 0 and 1 = concordance; score 2 = minor, clinically insignificant discordance; scores 3 and 4 = clinically significant discordance) by the subspecialty faculty members who rendered the final interpretation. RESULTS There were 158 clinically significant discrepancies out of 21,482 preliminary interpretations, for a discrepancy rate of 0.7%. There was no statistically significant difference in rates across subspecialties or between adult and pediatric examinations (cardiothoracic, 1%; abdominal, 0.7%; neuroradiology, 0.6%; musculoskeletal, 0.7%; pediatrics, 0.8%). MR and CT interpretations had significantly higher rates than ultrasound (MR, 1.4%; CT, 0.9%; ultrasound, 0.2%; P < .001). Within neuroradiology, there was a significantly higher rate for MR than CT (1.5% vs 0.6%, P < .01), and within abdominal radiology, there was a significantly higher rate for CT than ultrasound (1.1% vs 0.2%, P < .01). CONCLUSIONS Discrepancy rates in this study were less than or comparable with those reported previously and within or lower than rates for practicing radiologists. Discrepancy rates varied among subspecialties and modalities, suggesting the use of a RADPEER system with attention to modality and subspecialty as a methodology for identifying areas for targeted resident education.

POEMS syndrome: radiographic appearance with MRI correlation.

POEMS syndrome is a rare disorder in which patients present with the hallmark signs of polyneuropathy, organomegaly, endocrinopathy, M protein and skin changes. Many other clinical findings are also often present, most notably osseous lesions. The MRI appearance of the bony lesions in POEMS syndrome has been described in five cases, four of which are in the non-English literature. We report the MRI appearance of the osseous lesions in a patient with POEMS syndrome who presented with sciatic neuropathy.

Equivocal Pediatric Appendicitis: Unenhanced MR Imaging Protocol for Nonsedated Children—A Clinical Effectiveness Study

PURPOSE To determine retrospectively the clinical effectiveness of an unenhanced magnetic resonance (MR) imaging protocol for evaluation of equivocal appendicitis in children. MATERIALS AND METHODS Institutional review board approval was obtained. Pediatric patients (≤18 years old) underwent unenhanced MR imaging and contrast material-enhanced computed tomography (CT) of the appendix between December 2013 and November 2014 and December 2012 and November 2013, respectively, within 24 hours after an abdominal ultrasonographic examination with results equivocal for appendicitis. Pertinent MR imaging and CT reports were reviewed for visibility of the appendix, presence of appendicitis and appendiceal perforation, and establishment of an alternative diagnosis. Surgical reports, pathologic reports, and 30-day follow-up medical records were used as reference standards. Diagnostic performance with MR imaging and CT was calculated with 95% confidence intervals (CIs) for diagnosis of appendicitis and appendiceal perforation. The Fisher exact test was used to compare proportions; the Student t test was used to compare means. RESULTS Diagnostic performance with MR imaging was comparable to that with CT for equivocal pediatric appendicitis. For MR imaging (n = 103), sensitivity was 94.4% (95% CI: 72.7%, 99.9%) and specificity was 100% (95% CI: 95.8%, 100%); for CT [n = 58], sensitivity was 100% (95% CI: 71.5%, 100%), specificity was 97.9% (95% CI: 88.7%, 100%). Diagnostic performance with MR imaging and CT also was comparable for detection of appendiceal perforation, with MR imaging (n = 103) sensitivity of 90.0% (95% CI: 55.5%, 99.8%) and specificity of 85.7% (95% CI: 42.1%, 99.6%) and CT (n = 58) sensitivity of 75.0% (95% CI: 19.4%, 99.4%) and specificity of 85.7% (95% CI: 42.1%, 99.6%). The proportion of examinations with identifiable alternative diagnoses was similar at MR imaging to that at CT (19 of 103 [18.4%] vs eight of 58 [13.8%], respectively; P = .52). The proportion of appendixes seen at MR imaging and at CT also was similar (77 of 103 [74.8%] vs 50 of 58 [86.2%], respectively; P = .11). CONCLUSION Unenhanced MR imaging is sensitive and specific for the diagnosis of equivocal appendicitis in nonsedated pediatric patients.

Embryology and imaging review of aortic arch anomalies

Congenital malformations of the thoracic aorta can be discovered on chest radiographs when associated with symptoms or found incidentally. We review the imaging anatomy and associations of many of the aortic arch malformations that can be encountered in adults and highlight key points with regard to their treatment and prognoses. An understanding of the normal and abnormal embryologic development of the aortic arch, with knowledge of their imaging features, may be important for improving diagnostic accuracy and patient care.

Ablation techniques for primary and metastatic liver tumors

Ablative treatment methods have emerged as safe and effective therapies for patients with primary and secondary liver tumors who are not surgical candidates at the time of diagnosis. This article reviews the current literature and describes the techniques, complications and results for radiofrequency ablation, microwave ablation, cryoablation, and irreversible electroporation.

Will they fit? Development of a measurement device to assess body habitus compatibility with MRI bore diameter for emergency trauma imaging.

Excessive obesity poses a significant limitation to radiographic magnetic resonance imaging (MRI), particularly related to aperture or bore diameter due to the patient’s girth. Determination of whether a patient will fit into the bore of the MRI scanner is currently accomplished using patient height, weight, and MRI technician experience. These simple methods have proven unreliable. We sought to develop a device and method which could accurately determine whether a patient would fit into the MRI scanner. We developed an MRI template prototype which was tested against the standard radiology methods in a pilot study (n = 6). We then performed a prospective validation study in adult human volunteers (n = 100) to assess the accuracy of the MRI template. We collected height, weight, shoulder and pelvis girth/diameter for each study participant to evaluate the body dimension measurements that would assist in determination of whether a patient would fit into the MRI scanner. Using the MRI template, we determined that 11 of the 100 study participants would not fit in the MRI scanner and 10 were confirmed to not fit into the MRI aperture [positive predictive value (PPV) 0.91 (0.58–0.99); negative predictive value (NPV) 1.00 (0.95–1.00), sensitivity 1.00 (0.69–1.00), specificity 0.99 (0.93–0.99), likelihood ratio positive test 90 (12.81–632), likelihood ratio negative test 0, accuracy 99%]. In comparison, the body measurement method did not perform as well [PPV 0.66 (0.34–0.90), NPV 0.97 (0.92–0.99), sensitivity 0.80 (0.44–0.97), specificity 0.95 (0.89–0.98), likelihood ratio positive test 17.97 (6.56–49.2), likelihood ratio negative test 0.209 (0.06–0.72), accuracy 94%]. This study confirmed that the use of an MRI template is an accurate tool in determining whether an obese patient can fit through the MRI bore and be accommodated in the MRI scanner.

Does Distance Matter? Effect of Having a Dedicated CT Scanner in the Emergency Department on Completion of CT Imaging and Final Patient Disposition Times

PURPOSE To evaluate whether presence of a CT scanner in the emergency department (ED) improves ED workflow by decreasing time between imaging requisition and completion, and time to final patient disposition. METHODS Institutional review board approval was obtained for this retrospective study conducted on 2,142 consecutive, acute thoracic, abdomino- pelvic imaging requests from 2 ED hospital campuses affiliated with the same academic institution, August 1 to October 31, 2012. Of these patients, only 1,696 had complete records and were used for analysis. One hospital had a CT scanner in the ED; the other was in the radiology department, 300 meters from the ED. Patients were stratified based on acuity of CT indication, interpreting radiologist training level, and time of day. Time points were compared between hospitals: (1) time of CT requisition receipt to time of scan initiation (2) time from scan initiation to time of preliminary report by resident or fellow, or verbally by staff to the ED; and (3) time of CT requisition receipt to time of final patient disposition. RESULTS Decreases in time, favoring the institution with the ED CT scanner, are 16 min (P < .0001); 15 minutes (P < .0001); and 19 minutes (P < .04) for the 3 times, respectively. Significant differences were seen in morning and overnight shifts and for CT reporting times with higher radiology levels of training (20 min, P = .04; and 18 min, P < .0001 for staff and postgraduate year-5 residents, respectively). CONCLUSIONS Presence of an ED CT scanner is associated with decreases in time to CT scan completion, radiologic interpretation, and patient disposition.

Inter-radiologist agreement for CT scoring of pediatric splenic injuries and effect on an established clinical practice guideline

BackgroundThe American Pediatric Surgical Association (APSA) advocates for the use of a clinical practice guideline to direct management of hemodynamically stable pediatric spleen injuries. The clinical practice guideline is based on the CT score of the spleen injury according to the American Association for the Surgery of Trauma (AAST) CT scoring system.ObjectiveTo determine the potential effect of radiologist agreement for CT scoring of pediatric spleen injuries on an established APSA clinical practice guideline.Materials and methodsWe retrospectively analyzed blunt splenic injuries occurring in children from January 2007 to January 2012 at a single level 1 trauma center (n = 90). Abdominal CT exams performed at clinical presentation were reviewed by four radiologists who documented the following: (1) splenic injury grade (AAST system), (2) arterial extravasation and (3) pseudoaneurysm. Inter-rater agreement for AAST injury grade was assessed using the multi-rater Fleiss kappa and Kendall coefficient of concordance. Inter-rater agreement was assessed using weighted (AAST injury grade) or prevalence-adjusted bias-adjusted (binary measures) kappa statistics; 95% confidence intervals were calculated. We evaluated the hypothetical effect of radiologist disagreement on an established APSA clinical practice guideline.ResultsInter-rater agreement was good for absolute AAST injury grade (kappa: 0.64 [0.59–0.69]) and excellent for relative AAST injury grade (Kendall w: 0.90). All radiologists agreed on the AAST grade in 52% of cases. Based on an established clinical practice guideline, radiologist disagreement could have changed the decision for intensive care management in 11% (10/90) of children, changed the length of hospital stay in 44% (40/90), and changed the time to return to normal activity in 44% (40/90).ConclusionRadiologist agreement when assigning splenic AAST injury grades is less than perfect, and disagreements have the potential to change management in a substantial number of pediatric patients.