Pre-hospital emergency medicine: a spectrum of imaging findings.

The goal of emergency medical services (EMS) is to provide urgent medical care and stabilization prior to patient transport to a healthcare facility for definitive treatment. The number and variety of interventions performed in the field by EMS providers continues to grow as early management of severe injuries and critical illness in the pre-hospital setting has been shown to improve patient outcomes. The sequela of many field interventions, including those associated with airway management, emergent vascular access, cardiopulmonary resuscitation (CPR), patient immobilization, and hemorrhage control may be appreciated on emergency department admission imaging. Attention to these imaging findings is important for the emergency radiologist, who may be the first to identify a malpositioned device or an iatrogenic complication arising from pre-hospital treatment. Recognition of these findings may allow for earlier corrective action to be taken in the acute care setting. This review describes common EMS interventions and their imaging findings.

Facial Fracture in the Setting of Whole-Body CT for Trauma: Incidence and Clinical Predictors.

OBJECTIVE: The objective of our study was to identify the incidence and clinical predictors of facial fracture in the setting of whole-body MDCT for trauma. MATERIALS AND METHODS: The clinical data from the electronic medical records, including the final radiology reports, of 486 consecutive patients who underwent MDCT for trauma (head, cervical spine, chest, abdomen, and pelvis examinations) with dedicated maxillofacial reconstructions from October 1, 2011, to July 31, 2013, were studied. The clinical variables were compared between cohorts of patients with and those without facial fracture. The two-sample t test was used to compare continuous variables, and the Fisher exact test was used to compare categoric variables. RESULTS: Two hundred sixteen (44.4%) patients had at least one fracture on the dedicated maxillofacial CT examinations, 215 of whom had facial physical examination findings (sensitivity = 99.5%). Of the 28 patients without documented physical examination findings, 27 did not have a facial fracture (negative predictive value = 96.4%). Statistically significant differences were found between positive and negative cases of facial fracture in patients with a Glasgow coma scale (GCS) score of 8 or less (p < 0.0001), an injury severity score of 16 or greater (p < 0.0001), acute alcohol intoxication according to blood alcohol concentration (BAC) (p = 0.0387), intubation at presentation (p < 0.0001), positive physical examination findings (p < 0.0001), and loss of consciousness (p = 0.0364). Falls from a height greater than standing height and open-vehicle collisions had the highest fracture rates (80.0% and 58.3%, respectively). CONCLUSION: A negative finding at facial physical examination reliably excluded fracture. Clinical variables positively associated with facial fracture included the following: GCS score of 8 or less, ISS of 16 or greater, alcohol intoxication according to BAC, intubation at presentation, loss of consciousness, and the presence of abnormal facial findings at physical examination.

Iterative reconstruction improves image quality and preserves diagnostic accuracy in the setting of blunt solid organ injuries.

This study aims to investigate the effect of iterative reconstruction (IR) on MDCT image quality and radiologists' ability to diagnose and grade blunt solid organ injuries. One hundred (100) patients without and 52 patients with solid organ injuries were scanned on a 64-slice MDCT scanner using reference 300 mAs, 120 kVp, and fixed 75 s delay. Raw data was reconstructed using filtered back projection (FBP) and three levels of iterative reconstruction (Philips iDose levels 2, 4, and 6). Four emergency radiologists, blinded to the reconstruction parameters and original interpretation, independently reviewed each case, assessed image quality, and assigned injury grades. Each reader was then asked to determine if they thought that IR was used and, if so, what level. There was no significant difference in diagnostic accuracy between FBP and the various IR levels or effect on the detection and grading of solid organ injuries (p > 0.8). Images reconstructed using iDose level 2 were judged to have the best overall image quality (p < 0.01). The radiologists had high sensitivity in detecting if IR was used (80 %, 95 % CI 76-84 %). IR performed comparably to FBP with no effect on radiologist ability to accurately detect and grade blunt solid organ injuries.

Imaging findings of acute intravascular thrombus on non-enhanced computed tomography.

Intravascular thrombosis and thromboembolism are critical diagnoses which are frequently made on contrast-enhanced computed tomography (CECT) or Doppler ultrasound. For a variety of reasons, some patients with acute intravascular pathology are imaged using CT without intravenous contrast. In the acute setting, the increased Hounsfield unit (HU) density of the thrombus compared to the blood pool allows the diagnosis to be made, or at least suggested, on non-enhanced computed tomography (NECT). The increased density of the clot is commonly referred to as the "hyperdense vessel sign." This is a well-known finding in the setting of stroke, but hyperdense vessels can also signal arterial or venous thrombosis in the chest, abdomen, pelvis, and extremities. Once a hyperdense vessel sign is noted on NECT, further exploration with CECT, angiography, or ultrasound may then be performed. Here, we present a pictorial review of the appearance of acute intravascular thrombosis as seen on non-enhanced computed tomography.

Qualitative and quantitative spermatic cord abnormalities at CT predict symptomatic scrotal pathology.

PURPOSE: To evaluate quantitative and qualitative spermatic cord CT abnormalities and presence of unilateral or bilateral symptomatic scrotal pathology (SSP) at ultrasound. METHODS: This retrospective study included 122 male patients (mean age 47.8 years) undergoing scrotal ultrasound within 24 h of contrast-enhanced CT (n = 85), non-contrast CT (NECT, n = 32) or CT-Urogram (n = 5). CECT quantitative analysis assessed differential cord enhancement using maximum Hounsfield unit measurements. Three fellowship trained body radiologists independently assessed qualitative cord abnormalities for both CECT and NECT. Qualitative and quantitative findings were compared with the presence of SSP. Reader performance, interobserver agreement and reader confidence were assessed for NECT and CECT. Quantitative cutoff points were identified which maximized accuracy, specificity, negative predictive value, and other measures. RESULTS: SSP was present in 36/122 patients (29.5%). Positive cases were unilateral in 30 (83.3%) and bilateral in 6 (16.6%). At quantitative assessment, 25% differential cord enhancement had the highest diagnostic accuracy (88.9%), with 90.5% positive predictive value, 88.4% negative predictive value, 96.8% specificity, and 70.4% sensitivity. At qualitative evaluation, CECT reader performance was excellent (aggregate AUC = 0.86; P < .001); NECT was poorly discriminatory, although remained significant (aggregate AUC = 0.67; P = .002). Readers had significantly higher confidence levels with CECT (P < .001). Qualitative inter-observer agreement was high for both CECT and NECT (ICC = 0.981 and 0.963, respectively). CONCLUSION: Simple quantitative assessment of differential cord enhancement is highly accurate and specific for SSP at CECT. Qualitative abnormalities at CECT and NECT are also both predictors of SSP, however, CECT significantly out-performs non-contrast exams.

Imaging pattern of intracranial hemorrhage in the setting of posterior reversible encephalopathy syndrome.

INTRODUCTION: Intracranial hemorrhage (ICH) has been rarely described in the setting of posterior reversible encephalopathy syndrome (PRES). However, existing studies have even more rarely addressed the imaging pattern of PRES-related intracranial hemorrhage. The primary purpose of this study was to define the imaging characteristics of subarachnoid and intraparenchymal hemorrhage in the setting of PRES, including the location of hemorrhage with respect to the regions of parenchymal edema. We also reviewed PRES-related clinical features. METHODS: We conducted a retrospective review of 263 patients with PRES seen at our institution between 2001 and 2008, and identified patients with PRES-related hemorrhage. We reviewed clinical charts and imaging studies of these patients in detail. The clinical data studied included factors predisposing to PRES (such as hypertension, eclampsia, immunosuppressant toxicity, etc.), mean arterial pressure, and coagulation parameters. Imaging characteristics we analyzed included the amount of hemorrhage, its location, multiplicity, and spatial relationship with parenchymal edema. RESULTS: We identified a total of 51 patients with PRES-related hemorrhage. The blood pressure was elevated in 80% of these patients, while 47% patients showed coagulopathy. Intraparenchymal hemorrhage (IPH) was present in 46 patients and subarachnoid hemorrhage (SAH) in 14. SAH spared basal cisterns in all patients, and was usually small in amount. IPH was often multifocal, and associated mass effect was rare. In most of the 51 patients, hemorrhage occurred near the parenchymal edema. CONCLUSIONS: The prevalence of ICH in PRES was 19.4% in our series. Both SAH and IPH can occur in association with PRES, typically in a location approximating that of parenchymal edema.

pH regulating transporters in neurons from various chemosensitive brainstem regions in neonatal rats.

We studied the membrane transporters that mediate intracellular pH (pH(i)) recovery from acidification in brainstem neurons from chemosensitive regions of neonatal rats. Individual neurons within brainstem slices from the retrotrapezoid nucleus (RTN), the nucleus tractus solitarii (NTS), and the locus coeruleus (LC) were studied using a pH-sensitive fluorescent dye and fluorescence imaging microscopy. The rate of pH(i) recovery from an NH(4)Cl-induced acidification was measured, and the effects of inhibitors of various pH-regulating transporters determined. Hypercapnia (15% CO(2)) resulted in a maintained acidification in neurons from all three regions. Recovery in RTN neurons was nearly entirely eliminated by amiloride, an inhibitor of Na(+)/H(+) exchange (NHE). Recovery in RTN neurons was blocked approximately 50% by inhibitors of isoform 1 of NHE (NHE-1) but very little by an inhibitor of NHE-3 or by DIDS (an inhibitor of HCO(3)-dependent transport). In NTS neurons, amiloride blocked over 80% of the recovery, which was also blocked approximately 65% by inhibitors of NHE-1 and 26% blocked by an inhibitor of NHE-3. Recovery in LC neurons, in contrast, was unaffected by amiloride or blockers of NHE isoforms but was dependent on Na(+) and increased by external HCO(3)(-). On the basis of these findings, pH(i) recovery from acidification appears to be largely mediated by NHE-1 in RTN neurons, by NHE-1 and NHE-3 in NTS neurons, and by a Na- and HCO(3)-dependent transporter in LC neurons. Thus, pH(i) recovery is mediated by different pH-regulating transporters in neurons from different chemosensitive regions, but recovery is suppressed by hypercapnia in all of the neurons.

Is observation for traumatic hemothorax safe?

BACKGROUND: Eastern Association for the Surgery of Trauma guidelines suggest tube thoracostomy (TT) be considered for all traumatic hemothoraces. However, previous research has suggested that some traumatic hemothoraces may be observed safely. We sought to (1) determine the safety of selective observation for traumatic hemothorax and (2) identify predictors of failed observation. METHODS: All patients with traumatic hemothorax from 2000 to 2014 at a Level I trauma center were identified and categorized by size as small (<300 cc) or large (≥300 cc) based on chest computed tomography (CT) scan measurements. Patients with no CT or with TT placement before CT were excluded. Patients were categorized into four intervention groups: (i) early TT (<24 hours after CT), (ii) failed observation (TT ≥24 hours after CT), (iii) successful observation (no TT), and (iv) inevaluable due to early mortality (no TT but died within 7 days). Univariate analyses compared outcomes between groups. Multivariate analyses identified independent predictors of failed observation. RESULTS: Three hundred forty patients met the inclusion criteria. 156 (46%) patients received early TT. Of the 184 patients that were initially observed, 121 (66%) were successfully observed, 53 (29%) failed observation, and 10 (5%) were inevaluable due to early mortality. Most of the successfully observed hemothoraces were small (119/121, 98%). Four independent predictors of failed observation were identified: older age, fewer ventilation-free days, large hemothorax, concurrent pneumothorax. Patients, who received TT were more likely than non-TT patients to receive tissue plasminogen activator, develop an empyema, have fewer hospital-free days, and are discharged to rehabilitation rather than home. When compared to early TT, failed observation was associated with a higher likelihood of discharge to rehabilitation but no difference in mortality, hospital-free days, or rate of empyema. CONCLUSION: Initial observation in select patients is safe and may result in better outcomes. The identified predictors of failed observation can help in clinical decision making regarding the need for TT in patients with traumatic hemothorax. LEVEL OF EVIDENCE: Therapeutic/care management, level IV.