What’s New in Emergency Radiology? – October 2021

3 weeks ago

Can Patient Triaging with Clinical Scoring Systems Reduce CT Use in Adolescents and Young Adults Suspected of Having Appendicitis?

Hyunjoo Song, Seungjae Lee, Ji Hoon Park , Hae Young Kim, Hooney Daniel Min, Jong-June Jeon, Kyoung Ho Lee, for the LOCAT Group. Radiology. 2021; 300:350-358.

 

Clinical Question: In order to reduce radiation to adolescents and young adults, can clinical scoring systems for acute appendicitis reduce CT use without a loss of diagnostic accuracy?

 

Methods: Retrospective review of a previous randomized clinical trial of 2888 patients with suspected appendicitis. Using 5 clinical scoring systems, patients were stratified in low, intermediate, and high probability groups. This study simulated CT having been performed for only the intermediate probability group, as the low and high probability groups could be observed clinically or receive appendectomy, respectively. Thus, the CT reduction rate was the number of patients in the low and high probability groups divided by the total of all 3 groups. The sensitivity and specificity were calculated for each scoring system. Additionally, a secondary analysis was performed to assess the CT reduction rate of each scoring system with the probability groups adjusted to target a sensitivity of 97.6% and specificity of 94.9% (the values in the sample when all patients received CT).

 

Results: CT reduction rates ranged from 55.6-71.1% for the 5 clinical scoring systems. However, sensitivity and specificity dropped to 48.7-81.2% and 79.0-97.8%, respectively. When raising the target of sensitivity and specificity to the CT diagnostic accuracy, CT reduction rate dropped to 0%.

 

Conclusion and Implication: Clinical scoring systems do not effectively preserve diagnostic accuracy for acute appendicitis. Importantly, the clinical trial this study draws from infers that 2msV CT examinations are non-inferior to 7msV for diagnosing acute appendicitis. The authors therefore encourage focusing efforts on reducing radiation dose rather than the number of scans.

 

Reviewer Note: This interesting study has important implications in regards to the diagnostic algorithm for appendicitis. However, it should be noted that this study has a few limitations, including its retrospective design, and there are also prior studies in which clinical scoring systems fare better. Certainly there is a role of clinical scoring systems in deciding whether a CT can be delayed while a patient is observed, or in the setting of inconclusive CT results. Ultrasound can also play a role in conjunction with clinical scoring systems.

See editorial by Vincent Mellnick:

https://pubs.rsna.org/doi/10.1148/radiol.2021210632

 

 

Use of Enteric Contrast Material for Abdominopelvic CT in Penetrating Traumatic Injury in Adults: Comparison of Diagnostic Accuracy Systematic Review and Meta-Analysis

Mostafa Alabousi, Nanxi Zha, and Michael N. Patlas

American Journal of Roentgenology. 2021; 217:560-568.

 

Clinical Question: Does enteric (oral and/or rectal) contrast increase diagnostic accuracy of CT in penetrating traumatic abdominopelvic injury in adults?

 

Methods: A systemic review and meta-analysis was performed including 12 studies with 1287 patients, with 389 patients having abdominopelvic injury confirmed intraoperatively. Enteric contrast was administered in 506 patients. Data pooling and meta-regression analysis were performed.

 

Results: The enteric contrast group showed a sensitivity of 83.8% and specificity of 93.8% while the non-enteric contrast group showed a sensitivity of 93% and specificity of 90.3%. No statistically significant difference was identified for sensitivity (p = .07) or specificity (p = .37) between the groups.

 

Conclusion: Enteric contrast did not improve diagnostic accuracy in penetrating abdominopelvic trauma. In fact, the author cites a study that administration of enteric contrast resulted in a 68 minute delay in CT examination. Thus, eliminating enteric contrast administration can expedite CT examination and further clinical care. Additional benefits include improved patient experience and reduced cost from reduced contrast utilization.

 

 

Overnight attending radiologist coverage decreases imaging-related emergency department recalls by at least 90%. 

Mughli, R.A., Durrant, E., Baia Medeiros, D.T. et al.

Emergency Radiology. 2021; 28:549–555.

 

Clinical Question: Does the presence of an overnight attending radiologist decrease the ED recall rate when compared to resident only coverage?

 

Methods: Retrospective matched cohorts of the 2 years prior to and 1 year following the introduction of overnight attending radiologist final reporting. Of return visits within 48 hours of initial discharge, those related to imaging from the first visit were identified using “string matching” of terms within triage notes, followed by review of triage notes and full chart reviews as needed.

 

Results: Out of 43,458 overnight imaging studies from 28,765 patient visits, 1,153 patients had repeat visits within 48 hours. The recall rate (related to imaging) of the resident only coverage cohorts was 0.39% (54/13,883) of imaging studies in the first year, and 0.42% (61/14,463) in the second year. This compares to the attending coverage year recall rate of 0.05% (7/15112). As a function of patient visits, the recall rates were 0.59% and 0.64% for the resident only coverage years and 0.07% for the attending coverage year, with an odds ratio of recall of 8.42 for the first year and 9.18 for the second year before the introduction of overnight attending coverage. Overall, the decrease amounts to 89% less recalls.

 

Conclusion: While the resident preliminary report discrepancy rates are low, there is a statistically significant decrease in the ED recall rate related to imaging with overnight attending radiologist coverage, thus improving patient care as well as reducing the burden of recalls to patients and the ED. This paper also suggests a model of a 2-hr window of autonomous resident reporting to preserve resident independence and enhance real-time teaching and feedback during overnight shifts.

 

 

CT findings and outcomes of acute cholecystitis: is additional ultrasound necessary?

Lee, D., Appel, S. & Nunes, L. Abdominal Radiology. 2021.

 

Clinical Question: What is the positive predictive value (PPV) of CT in the diagnosis of acute cholecystitis and does follow-up ultrasound provide additional clinically useful information?

 

Methods: Retrospective study at an urban health system of CTs with abnormal gallbladder findings over a 25 month period. The review included any US performed within 72 hours of the initial CT. Surgical pathology, fluid analysis and clinical course were used to assess outcomes. Case stratification was performed by the radiologist’s degree of confidence in diagnosing acute cholecystitis, and positive/negative predictive values were calculated.

 

Results: Out of 468 CT studies meeting criteria, 192 were read as concerning for acute cholecystitis. The PPV of CT without US was 44.7% and 50.5% with a follow-up US (p=0.41). No significant difference was seen in high confidence CT reports when US was added, while for less confident CT reads, a subsequent ultrasound with high confidence of cholecystitis increased the PPV from 45% to 90%. Additionally, a follow-up negative ultrasound after a negative or indeterminate CT significantly further lowered the negative predictive value.

 

Conclusion: CT examinations with high suspicion for acute cholecystitis did not have significant clinical benefit from a follow-up US. However, CT reports raising suspicion of acute cholecystitis with a lower level of confidence did show a benefit with follow-up US examinations to help support the suspicion (thereby increasing PPV).

 

 

Diagnostic utility of computed tomography in patients presenting to the emergency department with unintended weight loss. 

Rao, S., Kikano, E.G., Smith, D.A. et al. Emergency Radiology. 2021; 28:771–779.

 

Clinical Question: Does CT examination aid in the diagnosis of the cause of unintended weight loss for patients presenting to the emergency department?

 

Methods: Retrospective review from 2004 to 2020 at a large tertiary care center and affiliated suburban hospital of patients with a chief complaint of weight loss. Clinical history and CT imaging was reviewed.

 

Results: Out of an eligible 133 patients undergoing CT examination, 65 had an identifiable cause of unintended weight loss (48.8%). Of the 133 patients, the most common diagnoses were non-malignant GI conditions (41) and cancer (30). CT correctly and definitively identified non-malignant GI conditions in 21 of the 41 patients, and showed findings highly suggestive of cancer in 27 of the 30 patients (which was subsequently confirmed by biopsy). Overall, the correct diagnosis was identified in 48.8% of patients (65/133).

 

Conclusion: CT examination serves as a useful tool in the diagnosis of unintended weight loss and should be considered in the undifferentiated patient in the emergency department given its high diagnostic yield and low false-positivity rate.

 

Caustic ingestion: CT findings of esophageal injuries and thoracic complications. 

Cutaia, G., Messina, M., Rubino, S. et al.

Emergency Radiology. 2021; 28:845–856.

 

Caustic ingestion can cause severe injury to the esophagus and thorax. This pictorial essay reviews mechanism of action of caustic injury, CT protocols, the role of endoscopy, and illustrates various injuries and their CT findings related to caustic ingestion. These include acute injuries (esophageal wall injury, perforation, esophago-respiratory fistula, and esophago-pleural fistula), subacute injuries (empyema and mediastinitis) and chronic injuries (strictures, diverticula, and carcinoma). Notable signs include wall edema/thickening, oral contrast extravasation, extraluminal air, and fluid collections. Knowledge of these signs is crucial as CT examination plays an important role in the detection and characterization of esophageal injuries and thoracic complications caused by caustic ingestion.

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