The diagnosis of pulmonary embolism without contrastis not always Challenging: be aware of hyperdense lumen sign

Acute pulmonary embolism (PE) diagnosis is a challenging task, despite the advanced diagnostic methods for both clinicians and radiologists. Awareness of the “hyperdense lumen sign” in patients obtained un-enhanced computarized tomography (CT) of chest mayhelp to establish an acute PE diagnosis, especially in clinically non suspected PE patients. A 78-year-old woman was brought to our emergency department (ED) with an aphasia complaint. The patient's dizziness improved in ED. Neurological examination returned to base line status but sinus tachycardia and low saturation value on room air were continuing. Un-enhanced CT of the chest demonstrates hyperdense material within the right main pulmonary artery. Contrast-enhanced CTPA demonstrated hypodense filling defect within the rigth main pulmonary artery consistent with PE. Independent of the patient's complaint, the measurement of all vital signs is important especially in elderly patients. Emergency physicians have to be aware of that the “hyperdense lumen sign” may point out PE and should be prevented from delayed recognition.


Introduction
It may sometimes be difficult to diagnose in emergency room because of that elderly patients cannot express themselves adequately and symptoms in this age group do not match exactly with the disease's characteristics. Independent of the patient's complaint, the measurement of all vital signs is important especially in elderly patients at this point. Acute pulmonary embolism (PE) diagnosis is a challenging task, despite the advanced diagnostic methods for both clinicians and radiologists. The most important step in the diagnosis of the disease is clinical suspicion. The most reliable diagnostic method is contrast-enhanced CT pulmonary angiography (CTPA) in which intraluminal filling defect sare seen after IV contrast agent administration [1]. Awareness of the "hyperdense lumen sign" in patients obtained unenhanced computarized tomography (CT) of chest with various cardiopulmonary symptoms may help to establish an acute PE diagnosis, especially in clinically non-suspected PE patients [2]. We report a 78-year-old female patient who was admitted to emergency service due to dysarthria and obtained an un-enhanced CT of chest because of her suffered to low saturation and diagnosed with acute PE by a waring of hyperdenselumen sign. Our aim was to raise awareness that the "hyperdense lumen sign" might help in the diagnosis of acute PE in patients with undifferentiated dyspnea.

Patient and observation
A 78-year-old woman was brought to our emergency department by her relatives with an aphasia complaint that had been intermittent for the last 6 hours. The patient's past medical history was unremarkable except hypertension. On original presentation, she was sub febrile with 37,8°C, with a blood pressure of 160/80mmHg,

Discussion
Many patients in emergency services are suffering from un enhanced thorax CT for distinct reasons. These include; pneumonia, emphysema, interstitial pulmonary disease, bronchiectasis. In addition, patients with non-specific cardiopulmonary symptoms without contrast due to impaired renal function and contrast allergy are also suffering from un enhanced CT. Recent publications have shown that hyperdensity in the pulmonary artery in the un enhanced CT scan will indicate pulmonary embolism [3][4][5][6]. This was first described by Gotway MB et al in year 2000 [7]. However, the number of cases in the literature still does not pass the fingers of a hand [8]. False positivity rate is very low, but false hyperdense luminal imaging may occur due to artefacts around the pulmonary artery [2]. The hyperdense appearance of the acute thrombus is Page number not for citation purposes 3 due to the increase in hemoglobin concentration in the clot due to decreased water content in the clot [8]. But this finding is rarely seen even if the patient has PE. Indirect findings such as pulmonary artery dilatation, pleural effusion, regional oligemia, and sub pleural pulmonary consolidation, which are not specific or sensitive, are well described [2]. However contrast enhanced CTPA is the most commonly used and reliable diagnostic method for PE, being aware of hyperdense lumen sign can help early detection of acute PE in patients with un suitable to contrast agent. In our case, the hyperdense lumen sign seen in un enhanced thorax CT obtained forun differentiated dyspnea, was headed us for acute PE and diagnosed in the early period after that the treatment started rapidly. However, confirmatory tests such as contrast-enhanced CTPA or ventilation perfusions cintigraphy are still recommended [5].

Conclusion
Emergency physicians have to be aware of that the "hyperdense lumen sign" seen in un enhanced thorax CT obtained from the patients with various cardio pulmonary symptoms, may point out PE and should be prevented from delaying recognition with confirmatory tests in the early period.

Competing interests
The authors declare no competing interest.