Mediastinal Widening Research Articles

Abstract 4121454: Machine-extractable Markers in Chest Radiograph to Predict Cardiovascular Risk in Screening Population

Introduction: Recent research has shown that AI is able to assess biological aging and cardiovascular disease (CVD) risk using chest radiographs. However, the lack of explainability of such deep learning algorithms hinders clinical utility and adoption. This motivates the current study which searches for and tests the use of machine extractable quantitative features in chest radiographs to predict CVD risk in population screening. Method: Chest radiograph measurements characterizing cardiomediastinal geometry, aortic calcification and tortuosity were handpicked for development of a segmentation-based feature extraction algorithm. The algorithm was applied on the PLCO lung screening dataset for analysis. The association between measurement-based imaging features, clinical characteristics (age, sex, BMI, smoking status, hypertension, diabetes, liver disease) with CVD mortality and 10-year major adverse cardiovascular events (MACE) were analysed by using proportional hazard regression, with feature selection done by LASSO. Result: Of 29,453 eligible subjects, 5693 subjects from a single study centre were used for fitting of all models. The median follow-up time was 19 years. A total of 32 imaging features were extracted and analysed. For both 10-year MACE and CVD mortality, model using imaging features, age, and sex performed similarly to model using conventional risk factors, and a deep learning chest radiograph CVD risk model. Two imaging features, mediastinal width at valve-level [HR 1.36 (1.23-1.50)] and maximal lateral displacement of descending aorta [HR 1.29 (1.18-1.42)] were found to be prognostic. To the best of our knowledge, these features have not been reported previously. Conclusion: Quantitative imaging features can predict CVD risk in chest radiograph similar to deep learning models while providing feature interpretability and explainability. Two novel imaging features prognostic of CVD risk were found and shown to be complementary to conventional risk factors.

Abdominal radiographic features of anticoagulant rodenticide toxicity in 14 dogs and 2 cats.

Anticoagulant rodenticide toxicity is commonly encountered in veterinary practice that can result in internal bleeding. We have observed dogs with retroperitoneal hemorrhage secondary to anticoagulant rodenticide toxicity. However, abdominal radiographic changes in dogs with rodenticide toxicity have not been studied and retroperitoneal hemorrhage secondary to rodenticide toxicity has rarely been reported. The objective is to describe abdominal radiographic features of anticoagulant rodenticide toxicity and concurrent thoracic radiographic changes in dogs and cats. Dogs and cats diagnosed with rodenticide toxicity and with available abdominal radiographs were included in this retrospective analysis. Board-certified radiologists reviewed the abdominal and thoracic radiographs. Evaluation of abdominal radiographic changes included assessment of peritoneal or retroperitoneal effusion, subcutaneous hemorrhage, and internal hemorrhage of abdominal organs. Fourteen dogs and two cats with confirmed rodenticide toxicity were included in the study. In dogs, retroperitoneal effusion (28.6%) was the most commonly observed abdominal radiographic change, followed by peritoneal effusion (14.3%). Thoracic radiographic changes in dogs included pleural effusion (63.6%) and mediastinal widening (63.6%) as the most common findings, followed by pulmonary hemorrhage (36.4%) and tracheal narrowing (36.4%). Subcutaneous hemorrhage or edema (9.1%) was also noted. No abdominal radiographic changes consistent with hemorrhage secondary to rodenticide toxicity were noted in the two cats. Based on our findings, it is suggested that rodenticide toxicity may result in retroperitoneal effusion even in the absence of thoracic disease. Therefore, abdominal radiographs may be valuable when suspecting hemorrhage due to coagulopathy. However, abdominal radiographic changes associated with rodenticide toxicity are considered rare in cats.

Management of malignant superior vena cava syndrome.

Superior vena cava (SVC) syndrome occurs due to obstructed blood flow through the SVC. It can present clinically on a spectrum, between asymptomatic and life-threatening emergency. Patients commonly report a feeling of fullness in the head, facial, neck and upper extremity edema, and dyspnea. On imaging, patients commonly have superior mediastinal widening and pleural effusion. The majority of cases are due to malignant causes, with non-small cell lung cancer, small cell lung cancer, and lymphoma the most commonly associated malignancies. When evaluating patients, a complete staging workup is recommended, as it will determine whether treatment should be definitive/curative or palliative in intent. If the patient requires urgent treatment of venous obstruction, such as in the cases of acute central airway obstruction, severe laryngeal edema and/or coma from cerebral edema, direct opening of the occlusion by endovascular stenting and angioplasty with thrombolysis should be considered. Such an approach can provide immediate relief of symptoms before cancer-specific therapies are initiated. The intent of treatment is to manage the underlying disease while palliating symptoms. Treatment approaches most commonly employ chemotherapy and/or radiation therapy depending on the primary histology. Mildly hypofractionated radiation regimens are most commonly employed and achieve high rates of symptomatic responses generally within 2 weeks of initiating therapy.

A Review of Literature on Thymoma: An Indolent Tumor of Anterior Mediastimum

Thymic tumours are a heterogeneous group of malignancies with a range of clinical presentations. The most common types are thymoma and thymic carcinoma, but overall it remains a rare cancer, and one without a clear aetiology. About 50% are diagnosed incidentlly with chest radiography. Thymoma is classified into different stages, which determine the prognosis and type of management. Different types of treatments are available for patients with thymoma. Thymectomy to remove the tumor is the most common treatment of thymoma. We present a case of 20 yr old male presented with shortness of breath, cough, chest pain and fever for past 15 days. Mediastinal widening and modratly pleural effusion in right sided chest seen on chest xray. CECT chest show soft tissue density lesion in anterior and superior mediastinum. FNAC was done that showed feature of thymoma. Biopsy also done that confirmed lymphocytic rich type B thymoma.

Tuberculosis Presenting as Anterior Mediastinal Mass - A Possibility in An Immunocompetent Child

A case of an 8-year-boy is reported who presented with a two month history of high-grade fever, associated with reduction in his appetite and subjective weight loss. He was treated empirically on the lines of bronchopneumonia, however, with no relief in his symptoms. Chest radiograph showed mediastinal widening, which prompted the need for a computed tomographic (CT) scan of the chest revealing an anterior mediastinal mass abutting the pericardium and compressing the great vessels. The possibilities of lymphoma or germ cell tumour were considered. The serum tumor markers were unremarkable. The child underwent midline sternotomy, with complete excision of mass. The histopathology of the lesion revealed multiple epithelioid cell granulomas with necrosis, and final diagnosis of a tuberculous lesion was made. The clinical course of this patient and the relevant literature is presented in this paper.

Type A Aortic Dissection: A Call for Vigilance in Chest Pain Diagnosis

Introduction: Acute aortic dissection (AD) is a rare and life-threatening condition associated with high mortality rates in the absence of prompt intervention. This article provides an in-depth examination of the clinical presentation, diagnostic approach, and management of Stanford type A AD in a 62-year-old hypertensive female patient with atypical symptoms.
 Case Report: The patient presented with retrosternal chest pain and rapidly worsening dyspnea, demonstrating a 3/6 diastolic murmur over the aortic area. Diagnostic findings included negative T-waves on ECG, significant mediastinal widening on chest X-ray, and transthoracic echocardiography revealing an intimal flap, ascending aorta dilation, and acute aortic insufficiency. Computed tomography confirmed a Stanford type A aortic dissection.
 Discussion: Acute AD poses a diagnostic challenge, as atypical presentations can lead to misdiagnoses. The case emphasizes the importance of considering AD in the differential diagnosis of chest pain and conducting thorough investigations, especially when faced with unusual symptoms. Management strategies, encompassing both pharmacological and surgical interventions, are crucial for addressing AD promptly.
 Conclusion: This case underscores the significance of recognizing both typical and atypical presentations of AD to ensure timely intervention and avoid potentially catastrophic outcomes. A comprehensive understanding of diagnostic approaches and management protocols is essential in the emergency setting. Overall, this article contributes to the growing body of knowledge surrounding acute aortic dissection and emphasizes the critical need for awareness and rapid intervention in clinical practice.

Diagnosis of a Case of Achalasia of the Cardiac at the Somine Dolo Hospital in Mopti

We report through this observation the diagnosis of a case of achalasia of the cardia in a 14-year-old adolescent at the Sominé Dolo hospital in Mopti. This was the first case of Achalasia of the cardia out of the 2650 gastroscopies carried out in Mopti from 2018 to 2022. The patient had no particular personal or family medical/surgical history. According to the symptoms, it was classified as Stage 3 of the Eckardt Score. The esogastroduodenal fibroscopy performed revealed a narrowing of the cardia and a jump when passing the endoscope. It was stage II at the time of diagnosis, according to the distension of the body of the esophagus during esophagogastric transit and a Radish tail image at the level of the esophagogastric junction. Frontal chest x-ray showed significant mediastinal widening. However, monomerism (essential examination) inaccessible in our context could not be achieved. The diagnosis of achalasia of the cardia was retained based on clinical, endoscopic and radiological arguments.

Mediastinal Lymphadenopathy Complicating into a Bronchonodal Fistula and Lung Abscess Formation – Rare Manifestation of Drug-resistant Tuberculosis

Pulmonary tuberculosis (TB) sometimes involves regional lymph nodes like mediastinal lymph nodes. These may resolve spontaneously or on treatment; or they may enlarge and result in various complications such as extrinsic bronchial inflammation, ulceration, or rarely erode through the bronchial wall. This erosion is seen radiologically as mediastinal widening or lymphadenopathy with atelectasis and consolidation termed “epituberculosis.” This is more frequently encountered in infants than older children and extremely rarely in adults. We hereby describe a rare case of a 14-year-old girl with mediastinal lymphadenopathy complicating into a bronchonodal fistula and lung abscess formation. A diagnosis of pulmonary rifampicin-resistant TB was obtained on repeated testing of sputum for GeneXpert. The patient was started on appropriate drug-resistant TB therapy and completed therapy successfully.

A Novel Tool for Distinguishing Type A Acute Aortic Syndrome from Heart Failure and Acute Coronary Syndrome.

Type A acute aortic syndrome (urgent AAS, UAAS) has a low incidence and high mortality rate; however, it is often missed or diagnosed late. Our aim was to create a new tool for distinguishing UAAS by using multiple modalities to select patients for CT aortography. This study included 75 patients with UAAS, 77 with acute coronary syndrome (ACS), and 81 with heart failure (HF) who received urgent treatment after propensity matching. Specific symptoms, past medical history, mediastinal width, region of interest (ROI) ratio in the lung base/apex, D-dimers, and troponin I were investigated to differentiate UAAS from ACS and HF. The most significant variables were selected to create a new scoring system. The UAAS score exhibited a performance AUC of 0.982. A simple UAAS score >1, excluding ROI ratios in lung base/apex, showed an AUC of 0.977, a sensitivity of 96%, and specificity of 92.41%. The results were validated using an external data set of 292 patients (simple UAAS score > 1: AUC of 0.966, sensitivity 93.33%, and specificity 95.36%). The simple UAAS score may be a valuable tool for suspecting UAAS and may reduce the likelihood of misdiagnosis or performing unnecessary CT aortography.

Etiological Pattern & Clinical Presentation of Dysphagia

Background & objective: : Dysphagia can cause significant morbidity and mortality, especially in older and paediatric populations. The study was undertaken to determine the demographic and clinico-pathological profile of the patients diagnosed with oesophageal dysphagia in a tertiary care hospital of Bangladesh. Methods: This cross-sectional study was conducted at the Department of Medicine & Gastroenterology in Sir Salimullah Medical College & Mitford Hospital over a period of 6 months, from March to August 2015. A total of 100 adult (aged ≥ 18 years) patients (respondents) of dysphagia of both sexes were included in the study. However, patients who dropped out before investigations being completed, or unconscious patients (as endoscopy cannot be done in unconscious patients) were excluded from the study. Result: The age distribution shows that patients were predominantly older (60%), male and rural resident. In terms of occupation, retired persons comprised the main bulk (38%). About half (49%) of the patients were middle-class and smoker. Presence of both solid and liquid food dysphagia was more or less common (44%), followed by solid food dysphagia alone (36%) and liquid food dysphagia alone (20%). A substantial proportion (78%) of patients presented with heart-burn as well. Probing the clue to dysphagia, some 7% of the patients gave history of ingesting chemical substances (either accidentally or as an attempt to suicide), 15% had history of taking steroid and 12% taking NSAIDs. History of radiation injury and history of ingesting foreign substances were rare. Over 60% of the respondents had co-morbid conditions like diabetes mellitus (28%), hypertension (23%), candidiasis (6%), lymphoma (3%). Clinical examination revealed 30% of the respondents nutritionally compromised (20% underweight and 10% overweight or obese). Nearly two-thirds (63%) were anaemiac with glossitis and koilonychia being present in 47 and 17% of the patients respectively. About one-third (32%) exhibited cervical lymphadenopathy. Of the 100 respondents, only 4 respondents were found with cardiomegaly, 4 with COPD, 2 with mediastinal widening. Endoscopy of upper GI tract showed 29% with ulceroproliferative lesion, 22% with multiple white patches in the whole length of oesophagus, 18% with stricture & narrowing of the oesophagus, 13% with malignant stricture & narrowing, 10% with proliferative lesion at mid oesophagus with narrowing of lumen and 8% malignant-looking ulcer with elevated margin in the lower oesophagus. Ba-swallow X-ray of oesophagus revealed 47 with filling defect in the lower oesophagus, 5 narrowing in the middle part of oesophagus and only 4 dilatations in the mid oesophagus. Twenty respondents had positive findings on USG of whole abdomen; of them, 10 had multiple solid tumors in liver. Others had hepatoma, mass in the epigastrium, cystitis, intraabdominal lymphadenopathy and splenomegaly. Based on symptoms, signs and laboratory findings, 42% were diagnosed as oesophagial carcinoma, 16% as drug-induced oesophageal ulcer and 11% as diabetes mellitus with oesophageal candidiasis. Conclusion: The most common cause of oesphageal dysphagia is carcinoma of oesophagus followed by drug-induced oesophageal ulcer and diabetes mellitus with oesophageal candidiasis. To reduce morbidity and mortality of various etiologies leading to dysphagia, prompt and early diagnosis is essential. Ibrahim Card Med J 2022; 12 (1): 40-45

Differentiation of acute inferior wall myocardial infarction caused by acute type A aortic dissection from atherosclerotic inferior myocardial infarction

Abstract Background Myocardial infarction (MI) caused by acute type A aortic dissection (AAD) is a rare but serious complication. To avoid unnecessary and possibly harmful treatment, differentiation of AAD-MI from atherosclerotic MI (AMI) is very important. However, there is a paucity of data regarding differentiation between AAD-MI and AMI. Purpose To compare the differences of clinical features between AAD-MI and AMI, and develop an effective way of differentiation. Methods Among 318 cases with AAD between 1982 and 2020, 18 cases (5.7%) had AAD-MI, of which 13 had inferior wall AAD-MI. Clinical features were compared with 25 consecutive inferior ST elevation AMI cases between 2017-2019. Categorial data and numerical data were compared using Fisher’s exact test and Student T test, respectively. Results Mean age and male/female ratio in AAD-MI and AMI were similar at 67.5 vs 66.3 years and 7/6 vs 13/12, respectively. The distribution of coronary risks factors and pain as presenting symptoms were similar in both groups. Initial systolic blood pressure (SBP) was significantly lower, and the incidence of shock was significantly higher in AAD-MI group compared to AMI group (SBP: 97.5 ± 26.4 vs 124.6 ± 32.7 mmHg, P = 0.014. shock: 9/13, 69.2% vs 5/25 20.0%, P = 0.0048). Although the heart rate was similar in both groups, AAD-MI group was more tachypnoeic than AMI group (27.8 ± 7.4 vs 22.7 ± 5.9/min, P = 0.046). All cases in both groups had ST elevation >1mm in inferior leads (by definition). There were no differences of the degree of ST elevation (2.46 ± 1.19 vs 2.54 ± 1.50 mm. P = 0.87), and the incidence of arrhythmias such as AV block. Chest X-ray showed higher incidence of mediastinal widening (MW) in AAD-MI group compared to AMI group (11/13, 84.6% vs 5/25, 20.0%. P =0.0003), whereas the incidence rates of cardiomegaly and congestive heart failure were not different. Pulse deficit (PD) and hemiplegia were seen in AAD-MI group only (pulse deficit: 5/13, 38.5% vs 0/25, 0%. P = 0.0026. hemiplegia: 2/13, 15.4% vs 0/25, 0% P = 0.11). The incidence of tamponade (T) and aortic regurgitation (AR) were higher in AAD-MI group than in the AMI group (T: 7/13, 53.8% vs 0/25, 0%. p=0.00014. AR: 8/13, 61.5% vs 4/25 16.0% P = 0.009). The combination of either PD, AR, or T increased the sensitivity up to 84.6% while the specificity was 84.0%. Intimal flap was successfully identified by bedside echocardiography in 7 out of 9 cases (77.8%) in AAD-MI group. Conclusion ADD-MI and AMI present with similar risk factors, clinical symptoms, and electrocardiographic findings. However, ADD-MI cases were associated with worse findings, such as, lower initial SBP, tachypnoea and had higher incidences of shock, PD, MW, T, and AR compared to AMI cases. Echo is of critical importance as it can identify abnormalities more specific for AAD (AR, T) and can make final diagnosis of AAD through visualizing the intimal flap.Summary tableA representative case

Abstract 12754: The Forgotten Circulation: Lymphovascular Malformation Presenting as a Complex Mediastinal Mass in a Young Adult

A 20-year-old transgender male presented with one week of intermittent shortness of breath and chest pain. He reported dizziness and increasing pain when playing the trumpet. His exam was unremarkable, but chest X-ray showed mediastinal widening and opacification of the retrosternal space (Fig. 1A). Chest CT showed a well-defined centrally enhancing prevascular mediastinal mass abutting the superior vena cava (SVC) and right heart (Fig. 1B). He was referred to a thoracic surgeon for evaluation. Subsequent chest CT venography and MRI demonstrated a progressively enhancing, part-solid and cystic mass with dilated veins draining into the SVC and a phlebolith. Due to imaging and clinical features, including a low probability of malignancy given negative tumor markers, lymphovascular malformation was favored over other possibilities such as thymoma, germ cell tumor, sarcoma, or Kaposiform hemangioendothelioma. After multidisciplinary discussions between cardiology, radiology, cardiothoracic and pediatric surgery, and a review at a dedicated vascular anomalies center, the consensus was for close surveillance. A 6-week follow-up MRI showed no significant change, but given increased dyspnea and chest pain, the decision was made to proceed with surgical resection via median sternotomy. The tumor was densely adherent to the right phrenic nerve, pericardium, and SVC but was excised completely without complications (Fig. 1C). Pathology confirmed a benign vascular malformation with lymphatic and venous components (Fig 1D). This diagnosis is more common in the pediatric population but a rare cause of dyspnea and chest pain in a young adult. This case illustrates the value of multimodality imaging and multidisciplinary collaboration among adult and pediatric subspecialists in the diagnosis and treatment of a rare, complex mediastinal mass in a young adult patient.

Clinical and Radiographic Predictors of Successful Coronary Angiography Through Right Radial Artery Access.

Background: One of the limitations of the right radial access approach is complex vessel anatomy, such as subclavian tortuosity. Several clinical predictors have been proposed for tortuosities, such as older age, female sex and hypertension. In this study, we hypothesised that chest radiography would add predictive value to the traditional predictors. Methods: This prospective blinded study included patients who underwent transradial access coronary angiography. They were classified into four groups according to difficulty: Group I, Group II, Group III and Group IV. Different groups were compared according to clinical and radiographic characteristics. Results: The study included 108 patients (54, 27, 17 and 10 patients in Groups I, II, III and IV, respectively). The rate of crossover to transfemoral access was 9.26%. Age, hypertension and female sex were associated with a greater difficulty and failure rates. Regarding radiographic parameters, a higher failure rate was associated with a higher diameter of the aortic knuckle (Group IV, 4.09 ± 1.32 cm versus Groups I, II and III combined, 3.26 ± 0.98 cm; p=0.015) and the width of the mediastinum (Group IV, 8.96 ± 2.88 cm versus Groups I, II and III combined, 7.28 ± 1.78 cm; p=0.009). The cut-off value for prominent aortic knuckle was 3.55 cm (sensitivity 70% and specificity 67.35%) and the width of mediastinum was 6.59 cm (sensitivity 90% and specificity 42.86%). Conclusion: Radiographic prominent aortic knuckle and wide mediastinum are valuable clinical parameters and useful predictors for transradial access failure caused by tortuosity of the right subclavian/brachiocephalic arteries or aorta.

Giant Morgagni hernia with transthoracic herniation of the left liver lobe and transverse colon: a case report

BackgroundA Morgagni hernia is a rare diaphragmatic hernia that is usually asymptomatic but can present with gastrointestinal and chest symptoms and is reported in many cases with strangulation. Here we report a rare case of a Morgagni hernia with transthoracic herniation of the left lobe of the liver and transverse colon that presented with abdominal pain.Case presentationA 54-year-old Saudi female presented with abdominal pain, vomiting, and shortness of breath. Chest radiography revealed an air-containing viscus and a wide mediastinum. Computed tomography confirmed the presence of a right-sided Morgagni hernia. Reduction of the defect contents and repair of the hernia together with cholecystectomy were successfully performed using the laparoscopic approach. The patient recovered smoothly with complete resolution of preoperative symptoms.ConclusionA Morgagni hernia is a rare diaphragmatic defect with an increased risk of incarceration. In addition to the omentum, transverse colon, and small bowel, the defect may involve the left lobe of the liver. Surgical repair is recommended in all cases of Morgagni hernia, to avoid the risk of incarceration.

Negative Pressure Pneumomediastinum: A Novel Concept of Spontaneous Pneumomediastinum Without Mediastinal Widening Following Weight Loss.

Spontaneous pneumomediastinum, supposedly attributed to air leakage from the respiratory tract, is a common complication of interstitial lung disease often resulting in mediastinal widening. However, several cases of pneumomediastinum without mediastinal widening have been observed. This study aimed to investigate the cause of pneumomediastinum in patients without mediastinal widening. This study included 41 patients diagnosed with pneumomediastinum using computed tomography (CT) between July 2011 and September 2021 at Yokohama Minamikyosai Hospital; patients had undergone previous CT showing no gas density. Based on a comparison with previous CT images, the patients were classified into two groups: without mediastinal widening and with mediastinal widening. Of the 41 patients, 13 and 28 had pneumomediastinum without and with mediastinal widening, respectively. There were no significant differences in the sex, age, body mass index, or pneumomediastinum distribution between the groups. However, the rate of weight loss per month was significantly greater in the group without mediastinal widening than in that with mediastinal widening. No significant differences were observed in the respiratory function test results between the two groups; that said, 10 of the 13 patients without mediastinal widening had restrictive disorders. Pulmonary disease in this group included idiopathic pulmonary fibrosis (n = 6), interstitial lung disease with collagen disease (n = 4), and other disease (n = 1). Pneumomediastinum occurred during periods of weight loss in all patients without widening, excluding two patients without data. Pneumomediastinum without mediastinal widening occurs during rapid weight loss and is often associated with restrictive lung disorders. The negative pressure attributed to the decreased plasticity of the lungs, which complements the space where the mediastinal fat has disappeared, is presumably the cause of pneumomediastinum. This pathophysiology is different from that of conventional pneumomediastinum attributed to increased intrapleural space pressure; thus, we propose to name the abovementioned pathophysiology "negative pressure pneumomediastinum".

Application of a Thoracic CT Decision Rule in the Evaluation of Injured Children: A Quality Improvement Initiative.

Differences in injury patterns in children suggest that life-threatening chest injuries are rare. Radiation exposure from computed tomography increases cancer risk in children. Two large retrospective pediatric studies have demonstrated that thoracic computed tomography can be reserved for patients based on mechanism of injury and abnormal findings on chest radiography. Implement a decision rule to guide utilization of thoracic computed tomography in the evaluation of pediatric blunt trauma, limiting risk of unnecessary radiation exposure and clinically significant missed injuries. A protocol for thoracic computed tomography utilization in pediatric blunt trauma was implemented using a Plan-Do-Study-Act cycle at our Level I pediatric trauma center, reserving thoracic computed tomography for patients with (1) mediastinal widening on chest radiography or (2) vehicle-related mechanism and abnormal chest radiography. We modified our resuscitation order set to limit default imaging bundles. The medical record and trauma registry data were reviewed for all pediatric blunt trauma patients (younger than 18 years) over a 30-month study period before and after protocol implementation (May 2017 to July 2018 and February 2019 to April 2020), allowing for a 6-month implementation period (August 2018 to January 2019). During the study period, 1,056 blunt trauma patients were evaluated with a median (range) Injury Severity Score of 5 (0-58). There were no significant demographic differences between patients before and after protocol implementation. Thoracic computed tomography utilization significantly decreased after implementation of the protocol (26.4% [129/488] to 12.7% [72/568; p < .05]), with no increase in clinically significant missed injuries. Protocol compliance was 88%. Application of decision rules can safely limit ionizing radiation in injured children. Further limitations to thoracic computed tomography utilization may be safe and warrant continued study due to the rarity of significant injuries.

Widened mediastinum at elderly: a challenge in the emergency room (ER)

A widened mediastinum is a feature often seen on a plain chest x-ray. When the mediastinum is greater than 6 to 8 cm, depending on which source, it is noted to be wide. A wide mediastinum has many causes which include thoracic aortic aneurysm of the ascending and proximal descending aorta, aortic dissection of ascending and proximal descending aorta, unfolding of the aorta, passing through traumatic aortic ruptura and non-vascular structural causes, such as hilar lymphadenopathy either infectious or malignant (lymphoma, seminoma, thymoma). At elderly, this finding constitutes a real challenge in the emergency room, which must be interpreted in the light of the hemodynamic condition of the patient, taking into account that in the scenario of chronic aortic syndrome it includes aneurysmal dilatations of the aortic root that can be dissected incompletely, presenting with latent intramural hematoma in ascending aorta until aortic tamponade with secondary obstructive shock.

199: GETTING DOWN TO THE HEART OF IT: A CASE REPORT OF SPONTANEOUS CORONARY ARTERY DISSECTION (SCAD)

Introduction: Spontaneous coronary artery dissection (SCAD) is a rare but fatal diagnosis that can often be misdiagnosed in young and middle-aged female patients who present with acute Myocardial Infarction-like symptoms without any classic cardiovascular risk factors. Description: A middle-aged female with no known medical history presented after she acutely became lightheaded, vomited and had new-onset chest pain. Upon arrival she was obtunded, so she was intubated. Her EKG showed 5mm ST elevation in the inferolateral leads, and her chest x-ray showed mediastinal widening. She was taken for a Computed Tomography (CT) scan, and her CT Chest was negative for dissection. She was then taken for a coronary angiogram where she underwent Percutaneous Coronary Intervention (PCI). During her angiogram, she was found to have a Type 1 SCAD. Her angiogram was complicated by her going into Ventricular Fibrillation (VF) for which she underwent Direct Current Cardioversion and returned to Normal Sinus Rhythm. She had 2 Drug Eluting Stents placed to the Ostial Proximal Right Coronary Artery and was started on norepinephrine due to cardiogenic shock. As she started to stabilize, she was weaned off norepinephrine and propofol and extubated. Further workup showed during a CT Angiography Head and Neck there was beading and undulation noted of the left mid-Internal Carotid Artery which could be indicative of Fibromuscular Dysplasia (FMD). Her SCAD was additionally managed with aspirin, ticagrelor, atorvastatin, and metoprolol with plans to closely monitor her FMD in the outpatient setting due to her risk for recurrent dissection. Discussion: This case shows the importance of early treatment and recognition of rare presentations of ACS such as SCAD. Most cases constitute a conservative approach with medical therapy as over time there appears to be spontaneous healing of the vessel wall, but when the patient is unstable such as in cardiogenic shock, VF, or has ongoing chest pain it warrants a more invasive approach with PCI and medical therapy. This case also shows that there may be an association between SCAD and FMD, such that emerging guidelines recommend after a SCAD event, patients should be screened for FMD with imaging of the renal, cerebrovascular and iliac arteries.

Abstract 11161: Thymic Hemorrhage – A Cause for Cardiac Arrest?

Introduction: Thymic hemorrhage is a rare cause of sudden cardiac death, particularly in adults. We present a 35- year- old with sudden “cardiac” death secondary to thymic hemorrhage. Case: A 35-year-old healthy man presented following witnessed cardiac arrest. CPR was initiated immediately. The initial rhythm was shockable, he was defibrillated, and ROSC was achieved. He was intubated on site and transferred to the hospital. Initial labs were negative for electrolyte derangements and drugs of abuse. His high-sensitivity troponin T was 238 ng/L (nl&lt;23 ng/L) and subsequently trended downward. His electrocardiogram showed non-specific ST-T abnormalities. His echocardiogram showed an ejection fraction of 25 to 29% with global hypokinesis. He was extubated on day 4 and scheduled for coronary angiography. On day 5, when he attempted to get out of bed, he lost consciousness and became pulseless. His initial rhythm was PEA, but with episodes of ventricular fibrillation during CPR, he was shocked accordingly. He had prolonged CPR, therefore, obviating advanced therapies. His autopsy showed only thymic hemorrhage. His coronary arteries were normal, with no signs of myocardial injury or myocarditis. Conclusion: Massive acute thymic hemorrhage is extremely rare in adults but is a rare but recognized cause of sudden death in utero and infants. There are only two reported cases of thymic hemorrhage in adults in the literature. Both the patients were nearly 40-year-old men who presented with chest pain. Initial imaging was consistent with mediastinal widening requiring thoracotomy that demonstrated hemorrhagic thymus. Similar to our patient, the reported cases were young men with no prior history of trauma. In contrast, our patient presented with cardiac arrest, and initial imaging was negative for mediastinal widening. The underlying etiology of cardiac arrest from thymic hemorrhage is poorly understood. Right atrial compression from acute hemorrhage of a benign thymic tumor was postulated as the cause of sudden death in a previously healthy 15-year-old boy. Our patient is a rare case since there are, to our knowledge, no reported cases in the literature of thymic hemorrhage as the cause of death in adults.

Frequency of Missed Findings on Chest Radiographs (CXRs) in an International, Multicenter Study: Application of AI to Reduce Missed Findings.

Background: Missed findings in chest X-ray interpretation are common and can have serious consequences. Methods: Our study included 2407 chest radiographs (CXRs) acquired at three Indian and five US sites. To identify CXRs reported as normal, we used a proprietary radiology report search engine based on natural language processing (mPower, Nuance). Two thoracic radiologists reviewed all CXRs and recorded the presence and clinical significance of abnormal findings on a 5-point scale (1—not important; 5—critical importance). All CXRs were processed with the AI model (Qure.ai) and outputs were recorded for the presence of findings. Data were analyzed to obtain area under the ROC curve (AUC). Results: Of 410 CXRs (410/2407, 18.9%) with unreported/missed findings, 312 (312/410, 76.1%) findings were clinically important: pulmonary nodules (n = 157), consolidation (60), linear opacities (37), mediastinal widening (21), hilar enlargement (17), pleural effusions (11), rib fractures (6) and pneumothoraces (3). AI detected 69 missed findings (69/131, 53%) with an AUC of up to 0.935. The AI model was generalizable across different sites, geographic locations, patient genders and age groups. Conclusion: A substantial number of important CXR findings are missed; the AI model can help to identify and reduce the frequency of important missed findings in a generalizable manner.