What’s New in Emergency Radiology? – November 2022

2 months ago

True-Positive Rate of RSNA Typical Chest CT Findings for COVID-19 Pneumonia in an Increasingly Vaccinated Population

Polyakov, N. J., Som, A., Mercaldo, N. D., Di Capua, J., Little, B. P., & Flores, E. J. (2022). True-Positive Rate of RSNA Typical Chest CT Findings for COVID-19 Pneumonia in an Increasingly Vaccinated Population. Radiology, 220680. Advance online publication.

https://doi.org/10.1148/radiol.220680

Clinical Question: Do vaccinated people have a similar true positive rate of RSNA Typical Chest CT Findings for COVID-19 pneumonia to those who are/were unvaccinated?

Methods: Retrospective cohort study of 652 patients (26% fully vaccinated) meeting inclusion criteria of RSNA COVID-19 classification of “COVID Typical” with either one positive or two negative PCR tests. Statistical logistic regression models of the true positive rate of vaccinated and unvaccinated patients with a COVID typical Chest CT with additional analysis including the peak of the current variant of concern (VOC) and calendar month.

Results: Overall, vaccinated individuals had a statistically significantly lower true positive rate (41%) compared to unvaccinated individuals (73%). However, broken down by VOC, statistical significance held true during the peaks of the Alpha and Delta variant, but not during the peak of the Omicron variant.

Discussion: Breakthrough infections among vaccinated individuals have previously been reported to have no findings or less sever findings on CT. That is consistent with the decreased true positive rate in this study. True positive fully vaccinated individuals were also likely to have higher rates of comorbidities associated with disease severity and longer time from vaccination to CT scanning. The latter fact also helps to explain the non-statistically significant difference in typical COVID-19 appearance between vaccinated and unvaccinated groups during the Omicron peak VOC time period given the lower effectiveness of the vaccine for this variant and the rapid waning of immunity. It should be noted that true positive values are influenced by disease prevalence, which had decreased during the time period, and vaccination, which had increased over the time period.

 

Traumatic Intracranial Hemorrhage on CT After Ground-Level Fall in Adult Patients Receiving Antithrombotic Therapy: A Retrospective Case-Control Study

Vardar, Z., Lo, H. S., Mariyampillai, M., & Kotecha, H. M. (2022). Traumatic Intracranial Hemorrhage on CT After Ground-Level Fall in Adult Patients Receiving Antithrombotic Therapy: A Retrospective Case-Control Study. AJR. American journal of roentgenology219(3), 501–508.

https://doi.org/10.2214/AJR.21.27274

Clinical Question: What is the frequency, distribution, and clinical course of traumatic intracranial hemorrhage (tICH) in patients on antithrombotic therapy who fall from ground level with good neurologic status.

Methods: Retrospective study of 1630 patients with a GCS >= 14 and no focal neurological deficit were included. The characteristics of hemorrhage, follow up imaging for change, and overall clinical course (INR level, need for neurosurgical intervention, and death) was reviewed. The control group patients were not on antithrombotic (antiplatelet or anticoagulant) therapy.

Results: Frequency of tICH in antithrombotic (4.4%) and control patients (3.1%) were not significantly different (p = 0.24). No significant difference in frequency of mass effect or midline shift was noted. However, increased frequency of hematoma (subdural or epidural) expansion was noted in the antithrombotic therapy cohort (p = 0.04). No differences were noted in the antiplatelet or anticoagulant subgroups of antithrombotic therapy.

Discussion: In patients with a ground-level fall and good neurologic status, there was no increase in the rate of tICH in the antithrombotic cohort. However, there was a mild increase in the rate of hematoma expansion. This may aid in clinical decision making that an initial head CT decision for ground-level fall should not be altered by the presence of antithrombotic therapy, but closer follow-up of a detected tICH subdural or epidural hematoma may be prudent.

Nonaccidental Injury in the Elderly: What Radiologists Need to Know

Badawy, M., Solomon, N., Elsayes, K. M., Soliman, M., Diaz-Marchan, P., Succi, M. D., Pourvaziri, A., Lev, M. H., Mellnick, V. M., Gomez-Cintron, A., & Revzin, M. V. (2022). Nonaccidental Injury in the Elderly: What Radiologists Need to Know. Radiographics : a review publication of the Radiological Society of North America, Inc42(5), 1358–1376.

https://doi.org/10.1148/rg.220017

This review article from RadioGraphics discusses the radiologist’s role in detecting signs of physical abuse, sexual abuse, and neglect to raise the suspicion for elder abuse. As per the article, signs of elder abuse often go unnoticed due to a lack of training to recognize signs and lack of evidence-based studies as compared to child abuse. Lack of communication between clinicians and radiologists and lack of standard procedure of imaging to assess for elder abuse are additional challenges. Risk factors for victims include poor physical health, mental illness, poverty and disruptive living environment, and demographics such as women.

Imaging red flags include:

  • Long bone fractures: spiral fractures, especially in the distal diaphysis
  • Distal ulnar fracture: associated with a victim raising the forearm in self-defense
  • High energy impact fractures: upper ribs and shoulder girdle (strong force required)
  • Facial fractures: left sided zygomatic fractures (given the dominant right-handedness of the general population)
  • Shoulder dislocations: rare to occur from a typical ground-level fall
  • Small bowel hematoma: duodenum being the most common for nonaccidental trauma
  • Multiple subdural hematomas: particularly with acute on chronic, multiple locations, or accompanied by a skull fracture
  • Soft tissue hematomas: although more common in elderly given the increased propensity of bruising, larger size or certain unusual locations such as lateral or anterior arm, head and neck and the posterior trunk are suspicious
  • Decubitus ulcers: presence of several ulcers at multiple sites, especially in unusual locations such as the thorax or shins
  • Signs similar in child abuse: posterior rib fractures and various stages of healing

Considering reported data that only 9% of abused elderly were alive after 13 year follow-up compared to 41% of non-abused elderly, identifying elder abuse earlier can prevent significant mortality. The article notes that improved communication between ordering and interpreting physicians as well as further research and standardized guidelines can help bridge this gap, similar to what currently occurs with suspected child abuse.

Diagnostic performance of triple-contrast versus single-contrast multi-detector computed tomography for the evaluation of penetrating bowel injury

Paes, F. M., Durso, A. M., Pinto, D. S., Covello, B., Katz, D. S., & Munera, F. (2022). Diagnostic performance of triple-contrast versus single-contrast multi-detector computed tomography for the evaluation of penetrating bowel injury. Emergency radiology29(3), 519–529.

https://doi.org/10.1007/s10140-022-02038-0

 

Clinical Question: Does triple-contrast (oral, rectal, and IV) provide better detection of bowel injury from penetrating abdominopelvic trauma compared to only IV contrast-only CT?

Methods: Retrospective cohort study of 997 patients scanned for penetrating injury, of which 143 patients went on to laparotomy. 56 of these patients received a triple-contrast CT, while the others received an IV-contrast only CT. All CTs were reviewed with readers blinded to presentation and outcome.

Results: Of the 143 patients, 45 patients had bowel injury in penetrating trauma (10 on triple contrast and 35 on IV contrast-only). Specificity and accuracy of triple-contrast CT (98% and 97-99%, respectively) was statistically significantly higher compared to IV contrast-only CT (66% and 78-79%, respectively). No statistically significant difference in sensitivity was noted, although this was 91% in the IV contrast-only CT and 75% in the triple-contrast CT.

Discussion: Gastrointestinal injury in a penetrating injury, often clinically silent, is a notorious diagnostic dilemma. The low frequency of bowel injury, including in this study with a trauma registry review of 997 patients with penetrating trauma, also presents an inherent limitation to studies addressing this topic. Increased diagnostic accuracy and specificity was attributed by the authors to enhanced visualization of the rent in the bowel wall with intraluminal contrast. The authors suggest that select cases with high suspicion of GI injury in penetrating trauma should consider triple-contrast CT with additional multi-institution and case control prospective studies necessary to further investigate the topic.

Ankylosis of the cervical spine increases the incidence of blunt cerebrovascular injury (BCVI) in CTA screening after blunt trauma

Vierunen, R. M., Haapamäki, V. V., Koivikko, M. P., & Bensch, F. V. (2022). Ankylosis of the cervical spine increases the incidence of blunt cerebrovascular injury (BCVI) in CTA screening after blunt trauma. Emergency radiology29(3), 507–517.

https://doi.org/10.1007/s10140-022-02022-8

Clinical Question: Do patients with ankylosis of the cervical spine have an increased incidence of blunt cerebrovascular injury (BCVI) on CTA after blunt trauma

Methods: Retrospective study of blunt trauma in patients with ankylosis of at least 3 consecutive cervical vertebral levels (etiologies of seronegative spondyloarthropathy, DISH, degenerative, or surgical) with BCVI detection on CTA as the primary outcome and stroke as the secondary outcome.

Results:

  • Out of 153 patients included, 29 patients had BCVI (19%) and 6 of those had strokes.
  • Compared to the general population of blunt trauma, BCVI rate was 7 times higher.
  • Cervical spine fracture was the only statistically significant predictor for BCVI (OR 7.44).
  • Degenerative spondylosis was the most common etiology of ankylosis of the cervical spine.
  • Vertebral artery injury (VAI) was by far more common than carotid artery injury.
  • Biffl scale I-IV was similar amongst the patients with ankylosis and the general population.

Discussion: Patients with ankylosis have a significantly higher risk of BCVI, particularly of the vertebral arteries. However, the authors suggest BCVI to be unlikely to occur in vertebral arteries in the absence of a cervical spine or skull fracture. Fractures of the ankylosed spine are susceptible to instability and have the strongest leverage at the craniocervical junction.

Ultrasound for Midgut Malrotation and Midgut Volvulus: AJR Expert Panel Narrative Review

Nguyen, H. N., Navarro, O. M., Bloom, D. A., Feinstein, K. A., Guillerman, R. P., Munden, M. M., Sammer, M., & Silva, C. T. (2022). Ultrasound for Midgut Malrotation and Midgut Volvulus: AJR Expert Panel Narrative Review. AJR. American journal of roentgenology218(6), 931–939.

https://doi.org/10.2214/AJR.21.27242

This review article in AJR discusses findings of midgut volvulus with malrotation detection on ultrasound. The authors review normal anatomy, including tips for identification of normal rotation (anatomy of the duodenum segments and normal SMA location) and findings of abnormal rotation (SMV anterior or to the left of the SMA, intraperitoneal course of the third portion of the duodenum anterior to the SMA, abnormal cecal position, and hypoplastic pancreatic uncinate process not extending posterior to the SMA and SMV). Detection of volvulus including the swirl sign are demonstrated.

The authors performed a literature review comparing ultrasound to upper GI series for the detection of malrotation and volvulus, and found similar ranges of sensitivity and specificity. The authors discuss advantages of upper GI series including familiarity to physicians, ability to perform concurrent contrast enema study, and conversion into a small bowel follow through. Disadvantages include non-portability, possible lack of on-site radiologist presence, and inter-operator differences. Advantages of ultrasound include its portable nature, ability to simultaneously evaluate for necrotizing enterocolitis and/or hypertrophic pyloric stenosis, decreased reliance on an on-site radiologist (assuming sonographer expertise), lack of radiation, and decreased cost. Disadvantages of ultrasound include operator variability with learning curve to identify important anatomic relationships, as well as potential for obscuration by bowel gas artifact. The authors suggest coordinated efforts to train sonographers and radiologists, as well as standardizing protocols for the use of ultrasound.

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