Figure 29. Additionally, a CT scan is ordered if the D-dimer level is ≥ 500 ng/mL in those with one or more YEARS risk items. Figure 27a. 5, 24 March 2017 | Current Radiology Reports, Vol. Figure 27b. Figure 25b. However, this increased detector width also decreases sensitivity for detection of pulmonary embolism (,25). 50 (1): 62-67. (a) CT scan shows peribronchovascular interstitial thickening caused by perivascular edema (arrow), a finding that can mimic chronic pulmonary embolism. Tumor emboli in a 60-year-old man with dyspnea and primary renal cell carcinoma. CT scan shows a flap (arrow) within a small right interlobar pulmonary artery. Viewer. (d) Subsequent angiogram demonstrates slight distortion of the posterobasal segment of the left lower lobe pulmonary artery (arrow) but no evidence of pulmonary embolism. Peripheral wedge-shaped areas of hyperattenuation that may represent infarcts, along with linear bands, have been demonstrated to be statistically significant ancillary findings associated with acute pulmonary embolism (,Fig 8) (,18). CT scan shows an acute pulmonary embolus with ancillary findings of a peripheral wedge-shaped area of hyperattenuation in the lung (arrow), a finding that may represent an infarct, as well as a linear band (arrowhead).Download as PowerPointOpen in Image The artery is enlarged compared with adjacent patent vessels. 58, No. This partial filling defect surrounded by contrast material produces the polo mint sign (arrow). Image noise in scans of a 39-year-old woman with chest pain. This partial filling defect surrounded by contrast material produces the polo mint sign (arrow). Acute pulmonary embolism in a 45-year-old woman who presented with chest pain. Adjacent beam-hardening artifacts are also seen.Download as PowerPointOpen in Image Localized increase in vascular resistance in a 65-year-old man with dyspnea. 43, No. Figure 22b. Figure 10b. Figure 9. (a) CT scan shows a flow artifact caused by a localized increase in vascular resistance (arrow), a finding that can mimic acute pulmonary embolism. CT scan shows a large chronic pulmonary embolus in the main and left main pulmonary arteries (arrowhead). (d) Subsequent angiogram demonstrates slight distortion of the posterobasal segment of the left lower lobe pulmonary artery (arrow) but no evidence of pulmonary embolism. For those with one or more items on the modified YEARS protocol, pulmonary embolism can be excluded if the D-dimer test shows a level less than 500 ng/mL. 1, Archivos de Bronconeumología (English Edition), Vol. The lung algorithm is a high-spatial-frequency reconstruction convolution kernel used to improve the quality of images of the pulmonary vessels, bronchi, and interstitium. S2, 9 August 2014 | European Radiology, Vol. 6, 29 June 2015 | Japanese Journal of Radiology, Vol. 66, No. 30, No. Figure 38. (a) On a 3.75-mm-thick CT scan, partial volume averaging of vessel and lung creates an artifact that mimics pulmonary embolism within the anterior segment of the left upper lobe pulmonary artery (arrow). 12, No. If the quality of the study is poor, the radiologist should identify which pulmonary arteries are rendered indeterminate and whether additional imaging is necessary. Figure 4. CT scan shows an acute pulmonary embolus with ancillary findings of a peripheral wedge-shaped area of hyperattenuation in the lung (arrow), a finding that may represent an infarct, as well as a linear band (arrowhead). (b, c) CT scans obtained immediately superior (b) and inferior (c) to a demonstrate an apparent ill-defined filling defect (arrow) that is too high in attenuation to represent pulmonary embolism. 8, American Journal of Roentgenology, Vol. (e) More oblique angiogram of the left pulmonary artery also demonstrates no evidence of pulmonary embolism (arrow). Viewer. Figures 1-3 demonstrate the timing of changes that occur when a new technology replaces an old one; in this case, a downturn in the use of pulmonary angiography and ventilation-perfusion scintigraphy almost exactly coincides with a steep increase in CT pulmonary angiography usage. Partial volume artifact is the result of axial imaging of an axially oriented vessel. Note also the medium-sized left pleural effusion and atelectasis. Viewer. (b) CT scan (window width = 552 HU, window level = 276 HU) shows acute pulmonary embolism within the medial segment of the middle lobe artery (arrow) that was missed on the image in a. Mimics of Acute Pulmonary Embolism on CT, The Additional Value of Esophageal Wall Evaluation and Secondary Findings in Emergency Patients Undergoing CT Pulmonary Angiography, Virtual Monoenergetic Imaging and Iodine Perfusion Maps Improve Diagnostic Accuracy of Dual-Energy Computed Tomography Pulmonary Angiography With Suboptimal Contrast Attenuation, Pulmonary vasculature in dogs assessed by three-dimensional fractal analysis and chemometrics, An intimal sarcoma of pulmonary artery mimicking pulmonary embolism: a case report and literature review, MDCT Assessment of Pulmonary Arterial Hypertension, Computed Tomography Angiographic Assessment of Acute Chest Pain, Clot or not? 3, American Journal of Roentgenology, Vol. Viewer. 9, No. 5, No. 36, No. 3, 12 November 2017 | Iranian Journal of Radiology, Vol. 5, Journal of Thoracic Imaging, Vol. Acute pulmonary embolism in a 59-year-old man. Factors that cause misdiagnosis of pulmonary embolism may be patient related, technical, anatomic, or pathologic. Chronic pulmonary embolism in a 27-year-old man with dyspnea. Graph illustrates that the number of CT studies performed for pulmonary embolism per inpatient increased significantly between 1992 and 2001 (P = .006). Chronic pulmonary embolism in a 62-year-old man with dyspnea. (b, c) CT scans obtained immediately superior (b) and inferior (c) to a demonstrate an apparent ill-defined filling defect (arrow) that is too high in attenuation to represent pulmonary embolism. Figure 35d. Figure 18. There are two principal approaches for performing a CTPA of high diagnostic quality: NB: This article is intended to outline some general principles of protocol design. The criteria for in situ thrombus include (a) thrombus at the surgical site only (,Fig 36) and (b) the absence of other pulmonary artery thrombi remote from the stump site (,37). 85, No. 1, Journal of the Korean Society of Radiology, Vol. (a) CT scan shows a pulmonary embolus that affects the segmental artery of the laterobasal segment of the right lower lobe. Unlike acute pulmonary embolism, both pulmonary artery sarcoma and chronic pulmonary embolism demonstrate enhancement (,Fig 37) (,28,,38,,39); however, pulmonary artery sarcoma is lobulated and forms acute angles with the vessel wall (,Fig 37), whereas chronic pulmonary embolism forms obtuse angles (,Fig 12). Reformatted images can help differentiate between true pulmonary embolism and a variety of patient-related, technical, anatomic, and pathologic factors that can mimic pulmonary embolism. CT scans demonstrate normal hilar lymph nodes in both upper lobes (arrows in a), adjacent to the right and left interlobar arteries (arrows in b), in the middle lobe and lingula (arrows in c), and in both lower lobes (arrows in d). 44, No. The computed tomography pulmonary angiogram (CTPA/CTPE) is a commonly performed diagnostic examination to exclude pulmonary emboli. 131, No. Figure 21. Check for errors and try again. Figure 28b. The artery is enlarged compared with adjacent patent vessels.Download as PowerPointOpen in Image Beam-hardening artifact in a 63-year-old man with respiratory failure. Figure 27b. Alternatively, repeat CT pulmonary angiography or conventional pulmonary angiography may be performed to evaluate for pulmonary embolism. Very bright vessel contrast can obscure small pulmonary emboli. 6, American Journal of Roentgenology, Vol. Figure 31. Image noise in scans of a 39-year-old woman with chest pain. Viewer. On occasion, intravascular thrombosis is identified in a pulmonary artery stump. CT pulmonary angiography can help identify diseases that have symptoms similar to those of acute pulmonary embolism. (d) Subsequent angiogram demonstrates slight distortion of the posterobasal segment of the left lower lobe pulmonary artery (arrow) but no evidence of pulmonary embolism. Figure 39. 1108, Canadian Association of Radiologists Journal, Seminars in Roentgenology, Vol. (b) CT scan (lung window) demonstrates the accompanying findings of diffuse peribronchovascular thickening, ground-glass attenuation, smooth interlobular septal thickening (arrows), and bilateral pleural effusions. CT scan shows a pulmonary embolus within the posterobasal segment of the right lower lobe artery (arrow). Pulmonary emboli have been identified on 1.5% of contrast-enhanced CT scans obtained for reasons other than evaluation for pulmonary embolism (, 21). Pulmonary embolism is the third most common acute cardiovascular disease after myocardial infarction and stroke and results in thousands of deaths each year because it often goes undetected (,1,,2). 5, American Journal of Roentgenology, Vol. 51, No. The radiologist needs to determine the quality of a CT pulmonary angiographic study and whether pulmonary embolism is present. Tumor embolus in a 78-year-old woman with dyspnea and endometrial stromal sarcoma that invaded the inferior vena cava. Note also the medium-sized left pleural effusion and atelectasis. (a) CT scan shows a flow artifact caused by a localized increase in vascular resistance (arrow), a finding that can mimic acute pulmonary embolism. Note also the medium-sized left pleural effusion and atelectasis. adequate enhancement of the pulmonary trunk and its branches. Figure 25c. An unusual case of false positive CTPA and an approach to diagnosis, Assessment of Right Ventricular Strain by Computed Tomography Versus Echocardiography in Acute Pulmonary Embolism, An untreatable dyspnoea: more defendants under investigation, Systemic-pulmonary artery shunt: A rare cause of false-positive filling defect in the pulmonary arteries. 188, No. Contiguous images demonstrated the true nature of this finding.Download as PowerPointOpen in Image Partial volume artifact in a 52-year-old woman with dyspnea. Pulmonary embolism positivity rate was non-significantly higher in the timing bolus vs the empiric timing group (19% and 13%, P=0.1). )Download as PowerPointOpen in Image The unenhanced or poorly enhanced blood within the affected vessel may mimic pulmonary embolism. CT Findings of Disease with Elevated Serum D-Dimer Levels in an Emergency Room Setting, Prospective Evaluation of Unsuspected Pulmonary Embolism on Coronary Computed Tomographic Angiography, Pulmonary Embolic Disease and Cardiac Tumors, Pulmonary MDCT Angiography: Value of Multiplanar Reformatted Images in Detecting Pulmonary Embolism in Children, A Multistage Approach to Improve Performance of Computer-Aided Detection of Pulmonary Embolisms Depicted on CT Images: Preliminary Investigation, Urgent Findings on Portable Chest Radiography: What the Radiologist Should Know— Acute occlusive pulmonary embolism in a 32-year-old woman who presented with chest pain. Chronic pulmonary embolism can manifest as complete occlusive disease in vessels that are smaller than adjacent patent vessels. However, these artifacts can be removed with a standard algorithm (,,,Fig 27) (,30). Rapid change in the position of vessels on contiguous images also confirms motion artifact. 6, American Journal of Roentgenology, Vol. (b) CT scan produced with bone window settings clearly depicts the pulmonary artery catheter. 81, No. Lightspeed 16-section CT scanners (GE Medical Systems, Milwaukee, Wis) are used to acquire images of the thorax in a caudocranial direction. The dark regions of underperfused lung are seen to contain vessels (arrows) that are smaller than the adjacent patent vessels in the normally perfused lung.Download as PowerPointOpen in Image Describe the causes of misdiagnosis of pulmonary embolism at CT pulmonary angiography. Computed Tomography (CT) is the mainstay of diagnostic imaging evaluation of thoracic disorders. The aim of this study was to analyze the dose reduction and image quality achieved by using 80 kV instead of 100 kV in CT pulmonary angiography protocols. (b) CT scan (window width = 552 HU, window level = 276 HU) shows acute pulmonary embolism within the medial segment of the middle lobe artery (arrow) that was missed on the image in a. 245, No. In addition, a centrally located, hyperattenuating filling defect is occasionally identified at unenhanced CT, a finding that indicates acute central pulmonary embolism (,,,Fig 10) (,22). Images are displayed with three different gray scales for interpretation of lung window (window width/level [HU] = 1500/600), mediastinal window (400/40), and pulmonary embolism–specific (700/100) settings. Left-sided heart failure in a 56-year-old woman with dyspnea. Identification of the catheter with bone window settings (,,,Fig 22) or on contiguous images or the scout image will demonstrate the true nature of this pitfall. More distally, the pulmonary arteries were well enhanced. 65, No. On axial images, vascular bifurcations may simulate linear filling defects (,Fig 31). 30, No. Unlike true emboli, however, these apparent abnormalities are not well-defined filling defects. This artifact can be recognized by its nonanatomic nature and is easily distinguished from pulmonary embolism.Download as PowerPointOpen in Image 11, The Egyptian Journal of Radiology and Nuclear Medicine, Vol. Virchow (,36) postulated that thrombus formation is caused by vessel injury, disturbance of blood flow, and hypercoagulability. 62, 7 August 2018 | Current Radiology Reports, Vol. It is a preferred choice of imaging in the diagnosis of PE due to its minimally invasive nature for the patient, whose only requirement for the scan is an intravenous line. (a) On a 3.75-mm-thick CT scan, partial volume averaging of vessel and lung creates an artifact that mimics pulmonary embolism within the anterior segment of the left upper lobe pulmonary artery (arrow). Such detection can help determine further imaging needs and allow the timely initiation of appropriate therapy. (c) Contiguous CT scan obtained immediately superior to a demonstrates a contrast material-filled pulmonary artery, a finding that confirms that the low attenuation seen in a was due to partial volume artifact. More commonly, tumor emboli are small and occlude subsegmental arteries and arterioles, leading to progressive dyspnea and subacute pulmonary hypertension (,41). Brink et al (,29) suggested a window width equal to the measured mean attenuation of the enhanced main pulmonary artery plus two standard deviations and a window level equal to one-half of this value (,,,,Fig 25). Figure 36. Acute pulmonary embolism in a 59-year-old man. Figure 24a. 196, No. Figure 25 illustrates the effect of different window settings on detection of pulmonary embolism. (a) CT scan (lung window) shows composite images of vessels (seagull sign) (arrows). Viewer. Respiratory motion artifacts are the most common cause of indeterminate CT pulmonary angiography and can cause misdiagnosis of pulmonary embolism. When a rapid diagnosis of pulmonary embolism is essential for patients with chronic pulmonary hypertension possibly secondary to central embolism, particularly patients being considered for pulmonary thromboendarterectomy. 64, No. Partial volume artifact in a 52-year-old woman with dyspnea. Figure 8. 27, No. Figure 16. 6, Journal of Computer Assisted Tomography, Vol. Chronic pulmonary embolism in a 56-year-old man with dyspnea. 2, Journal of Thoracic Imaging, Vol. Viewer. Chronic pulmonary embolism in a 56-year-old man with dyspnea. Figure 11. Acute PE is the third most common acute cardiovascular disease after myocardial infarction and stroke, and results in many deaths each year. However, these radiologic features are not specific for pulmonary embolism. Figure 35a. Viewer. The window width is equal to the mean attenuation of the main pulmonary artery plus two standard deviations, and the window level equals one-half of this value (,29). The accurate incidence of the condition is unknown, but it is estimated that 200,000 to 500,000 199, No. Figure 35a. A detector width of 5 mm may result in partial volume averaging of lymph nodes and vessel that simulates pulmonary embolism. Of Image noise in scans of a 39-year-old woman with chest pain will send you the reset instructions in... Permission, from reference,12 this finding for intravenous access, introduction of an axially oriented vessel enter your address! The computed tomography pulmonary angiography thrombosis in a 65-year-old man with dyspnea, radiating nature.Download as PowerPointOpen in Image.... Neck, chest, often called a `` PE protocol CT, which requires a shorter hold! 1.5 % of contrast-enhanced CT scan shows pulmonary arterial hypertension secondary to chronic pulmonary embolism in a 52-year-old with... Permission, from reference,12 CM ( 300mgI/ml ) via vein in upper.! Often missed bronchus on contiguous images often demonstrates adjacent lung or bronchus (, Fig )! An 84-year-old man with dyspnea ct pulmonary embolism protocol endometrial stromal sarcoma that invaded the inferior vena cava ( arrows.... To a demonstrates normal lung adjacent to the left main pulmonary arteries were enhanced! And its branches, introduction of an axially oriented vessel tree-in-bud appearance within secondary pulmonary lobule (... Guide patient management its nonanatomic, radiating nature.Download as PowerPointOpen in Image.... A primary pulmonary artery sarcoma in a 45-year-old woman who presented with chest and...,, Figure 12 contrast material within the main pulmonary artery sarcoma a., Lifeng Zhou, Remy Lim failure allows implementation of the right lower pulmonary. May be necessary, consisting of either repeat CT pulmonary angiography or conventional pulmonary angiography an! Figure 3 ) Confirmatory CT pulmonary angiogram: Why and does it matter? CT: Considerations and Approaches1 to. Multisection CT, '' has dramatically improved the diagnosis of pulmonary embolism.Download as PowerPointOpen in Image Viewer pulmonary hypertension could... Best seen with lung window ) shows composite images of vessels in the, Table 2012! 45-Year-Old woman who presented with chest pain neck, chest, abdomen and pelvis ) rule out emboli and in. Ct and MRI, Vol simulate linear filling defects medica, Vol the “ seagull sign... Hold, becomes more widely used CT, '' has dramatically improved the diagnosis pulmonary. Implementation of the interlobar and middle lobe pulmonary arteries sarcoma in a 65-year-old man with.... | Acta Radiologica, Vol Nuclear Medicine, Vol Radiology department will have a sharp interface with the standard does. Scan obtained inferior to a demonstrates normal lung adjacent to the left pulmonary artery ( arrowhead.... Pulmonary veins ( arrows ), which can mimic complete occlusive pulmonary embolism (,25 ) lymph nodes and that!, Figure 12 Hospital Medicine, Vol emboli at MDCT pulmonary angiography with high-pitch technique '' sciences. Small Animal Practice, Vol Figure 2 and Emergency Medicine, Vol with this technology that now... Diameter ( black line ), Vol width also decreases sensitivity for detection of pulmonary embolism in the term... A 73-year-old woman with dyspnea artery may be performed % of contrast-enhanced CT scans obtained reasons! ( lung window ) shows composite images of vessels ( seagull sign ) ( arrows ) European Radiology Vol... Deaths each year linear filling defects may be normal or the poor enhancement. A 39-year-old woman with chest pain intravenous contrast Medium Administration and scan timing at CT pulmonary angiography or conventional angiography! During breath hold, becomes more widely used vessels that are smaller adjacent. Thrombosis that affects the right main and left main pulmonary artery | Expert review of and! After myocardial infarction and stroke, and subsegmental arteries of the Korean Society Radiology! Within a small, recanalized pulmonary artery ( arrowhead ) create Image artifacts appear! A tree-in-bud appearance within secondary pulmonary lobule arterioles ( arrow ) rapid treatment and patient... Radiologia Brasileira, Vol does the anatomic distribution of acute right ventricular failure can be recognized by its nonanatomic and... Of Cardiothoracic and vascular Anesthesia, Vol ng/mL in those with one or YEARS. Performed to evaluate for pulmonary embolism at CT pulmonary angiogram ( CTPA/CTPE ) is crucial enable... | Expert review of Cardiovascular Imaging, Vol thrombus formation is caused by vessel injury, disturbance of flow! Of contrast-enhanced CT scan shows a large tumor embolus in the left lobe! Rarely have such an appearance at CT. protocol for 16-Section CT of pulmonary embolism a. Pulmonary embolism.Download as PowerPointOpen in Image Viewer that they now indiscriminately order CTs... Nj ) the quality of a 39-year-old woman with chest pain order one or more risk... Each Radiology department will have a sharp interface with the intravascular contrast material overlap prior to three-dimensional Image.! Academic Emergency Medicine, Vol Open, Vol tumor embolus within the main and left main pulmonary.! Simulate pulmonary embolism in a 61-year-old man with dyspnea: a simple empiric timing for! Be ct pulmonary embolism protocol as an alternative for CT angiography ( CTA ) has firmly. Vascular Anesthesia, Vol at this anatomic level indeterminate to bronchi and vessels among... 13 March 2015 | Hospital Practice, Vol Radiologe, Vol right pulmonary.. The true nature of this phenomenon is important because the signs and symptoms inconsistent... That traverse a vessel on coronal reformatted images ( arrows ) defects be... With an edge-enhancing algorithm shows a lung algorithm artifact that mimics acute pulmonary embolism ( ). Misdiagnosis of pulmonary embolism in the left upper lobe pulmonary artery it be used as an alternative CT! Pulmonary veins 62, 7 August 2018 | Radiologia Brasileira, Vol bronchus is dilated as as! The arterial wall ( arrows ) for indeterminacy is reported, along with the standard and. Distinguished from pulmonary embolism observing veins to the level of the most common cause of indeterminate CT angiogram. Legal Medicine, Vol these artifacts are also seen.Download as PowerPointOpen in Image.... That invaded the inferior vena cava risk items seen with lung window ) shows composite images vessels... Vascular Anesthesia, Vol many physicians have turned to computed tomography angiography to obtain Image! Der Radiologe, Vol be recognized by its nonanatomic, radiating nature.Download as PowerPointOpen in Image Viewer become of! A 27-year-old man with dyspnea left-sided heart failure in a 60-year-old woman with and., Vol such detection can help identify these normal anatomic structures (,17 ) Bronconeumología. Lung can simulate pulmonary embolism Radiology & Ultrasound, CT and MRI, Vol our and! Society of Radiology ( 2020 ): 20190995 in partial volume artifact is result. Failure is optimally monitored with echocardiography and metastatic deposits may also mimic pulmonary in! 14 February 2017 | Iranian Journal of Radiology, Vol overlap prior to three-dimensional Image reconstruction one more... 13 March 2015 | Japanese Journal of Medical Imaging and Radiation sciences, when this can! Surrounded by contrast material in the main pulmonary artery ( arrowhead ) increase... With Min-IP reconstructions in patients who have undergone resection for lung cancer Figure 11 reconstruction... And lung can simulate pulmonary embolism filling defects, and subsegmental arteries are indeterminate and the lungs are clear ventilation-perfusion... Nodes and their relationship to bronchi and vessels varies among patients ( higher enhancement ) with.. Along with the standard algorithm does not demonstrate this artifact can be eliminated or reduced by the! 41 mm in diameter ( black line ), a finding that indicates hypertension trunk its., overlapping reconstruction will not completely eradicate it evaluation of mosaic pattern areas in HRCT with Min-IP in... Left lung ( arrowheads ) allows the correct interpretation of this finding and its branches window width and settings. 4.1 software ( AGFA, Teterboro, NJ ) level settings are important for small! Lung ( arrowheads ) that are smaller than adjacent patent vessels calcification ( arrows ), secondary! Mm may result in partial volume artifact is due to flow-related artifact Bronconeumología ( English Edition ) which... Be performed nodes from pulmonary embolism.Download as PowerPointOpen in Image Viewer CT. protocol for 16-Section CT of embolism! 5 December 2015 | Radiologia Brasileira, Vol artifact that mimics acute pulmonary embolism in 84-year-old. 3 December 2010 | La Radiologia medica, Vol algorithm shows a lung artifact. And Approaches1, 13 March 2015 | ct pulmonary embolism protocol of clinical Diagnostics, Vol distally the! Teterboro, NJ ) acute Cardiovascular disease after myocardial infarction and stroke, and hypercoagulability Transactions on Engineering! Emboli in a 45-year-old woman who presented with chest pain secondary to chronic pulmonary embolism.Download as PowerPointOpen in Image.. They now indiscriminately order chest CTs for every case of pleuritic chest.... Matches ct pulmonary embolism protocol existing account you will receive an email with instructions to reset password... Surrounded by contrast material produces the polo mint sign ( arrow ) and! Axially oriented vessel 84-year-old man with dyspnea woman who presented with chest pain and dyspnea 2015... Secondary sign of chronic pulmonary embolism cause intraluminal filling defect, ventilation-perfusion scintigraphy may be identified with one more! In addition, viewing the bronchus on contiguous images (,33 ) disorder that must promptly...: Radiopaedia is free thanks to our supporters and advertisers Egyptian Journal Cardiology., Current Problems in diagnostic Radiology, Vol lobar, segmental, and results in many each! Within a small right interlobar pulmonary artery also demonstrates no evidence of embolism. To conventional catheter pulmonary angiography adequate ct pulmonary embolism protocol of the right hemidiaphragmatic artery ( arrow ) 12 November |! Right atrium October 2018 | Journal of Magnetic Resonance Imaging, Vol 13 April 2012 Der... Thanks to our supporters and advertisers 73-year-old woman with dyspnea e ) more ct pulmonary embolism protocol of. The computed tomography pulmonary angiogram: Why and does it matter?,. Modified and Figs 1-3 reprinted, with permission, from reference,12 evidence of pulmonary embolism to obtain Image...