Over the past two decades, however, catheter angiography has become almost entirely supplanted by CT angiography (CTA), which is now the … Methods: In group A, eight patients had nondiagnostic pulmonary CTA studies. Readers were not blinded to the CTA protocol used. Materials and methods: IRB approved this retrospective study. For scanner/protocol combinations When lung scintigraphy is not available or is contraindicated, an optimized pulmonary CTA protocol should be used. By Carole A. Ridge et al. The CT Coronary Angiogram is a simple procedure without any pain and anxiety . The contrast agent is injected into a vein (not an artery as in conventional angiography), usually in the arm. Significance values were set at p ≤ 0.05. 50 patients with acute/chronic renal failure were examined on a 3 rd generation dual-source CT with an optimized DE CTPA protocol and a low CM injection protocol (5.4 g iodine). Concern exists regarding the image quality of pulmonary CTA in pregnant patients [4–7]. Second, triple rule-out CT protocol is associated with significantly higher radiation dose when compared to the CTPA protocol, but with low diagnostic yield of less than 10%. TABLE 2: Opacification of the Pulmonary Arteries on CT Angiography. Calculations were performed on a standard PC using a statistical analysis program (Minitab, version 15, Minitab). Studies analyzing pulmonary CTA of pregnant patients have confirmed that pulmonary arterial opacification is reduced during pregnancy [4, 7, 19, 20] and that transient interruption of the contrast bolus by unopacified blood from the IVC may occur more often in pregnant patients than in the general population [7]. A D-dimer assay might be a preferred alternative to test for pulmonary embolism, and that test and a low clinical prediction score on the Wells test or Geneva score can exclude pulmonary embolism as a possibility. A focal increase in vascular resistance from consolidation or atelectasis. Lung scintigraphy is not susceptible to the hemodynamic effects of pregnancy and remains a reliable tool for excluding PE in patients with normal findings on chest radiography while additionally conferring a lower maternal radiation dose than pulmonary CTA [12, 13]. PE was diagnosed in one patient. In group B, two patients had nondiagnostic studies. CT pulmonary angiography in patients with acute or chronic renal insufficiency: Evaluation of a low dose contrast material protocol. When used in conjunction with validated clinical decision tools like modified Wells criteria, CT-angiography is highly sensitive (good at detecting PE when it's there and ruling it out when it's not) and specific (generating few false-positive results). The adequate group included CTA studies with good pulmonary arterial enhancement and without significant noise or motion artifact. Historically, catheter-directed pulmonary angiography has been used most commonly for the diagnosis of suspected pulmonary embolism (PE). Evaluation of subjective image quality involved categorizing a study as either adequate or inadequate on the basis of one’s ability to diagnose PE, the adequacy of pulmonary arterial opacification, and the presence or absence of significant motion artifact and image noise. The flow rate was kept constant at 4 mL/s throughout the procedure. There was a strong positive relationship between mean pulmonary arterial attenuation and good objective image quality (r = 0.67, p = 0.001). This study presents and evaluates a CT pulmonary angiography protocol dedicated to pregnant women. These measurements were then combined to calculate mean pulmonary opacification. Experimental studies have shown that cardiac output is inversely related to peak arterial enhancement and time to arrival of contrast material in the aorta [21]. During bolus tracking, the patient was instructed to breathe quietly. A Combination of Normal-Dose Corticomedullary Phase With Low-Dose Unenhanced and Excretory Phases, Review. Evaluation of subjective image quality involved categorizing a study as either adequate or inadequate on the basis of one’s ability to diagnose PE, the adequacy of pulmonary arterial opacification, and the presence or absence of significant motion artifact and image noise. Furthermore, specific variations between both patient groups that may affect vascular opacification including cardiac function, height, and weight were not recorded at the time of image reinterpretation. We thank the CT radiographers at St. Vincent’s University Hospital—in particular, Susan Collins and Sheena O’Keeffe—and chief physicist Michael Casey for their important contributions to image acquisition and dose calculation in this study. The current standard of care for members with suspected pulmonary embolism is a spiral CT scan, also called a CTA, CT PA (computed tomography pulmonary angiography), MDCT (multidector CT) or helical CT scan. Two other patients underwent lung scintigraphy after an initial nondiagnostic CTA. Keywords: Computed tomography pulmonary angiography Diagnosis Pulmonary embolism Introduction Computed tomography pulmonary angiography (CTPA) ... PE. A total of 198 studies performed with four CM injection protocols varying in CM volume and iodine delivery rates (IDR) were retrospectively … Three of 11 CTA studies judged to have transient interruption of the contrast bolus in group A were considered of diagnostic quality at the time of image acquisition and by subjective image quality evaluation, but the mean pulmonary arterial enhancement was classified as poor in two and as adequate in one of these studies. A thoracoabdominal gradient exists between the IVC and the right heart. This IRB-approved study comprised 150 patients with suspected pulmonary embolism (78 male; mean age 65 ± 17years). Total blood volume increases by 50% during early pregnancy. Its use in pregnant patients has consistently risen in recent decades . The mean pulmonary attenuation was also higher in group B than in group A: 321 ± 148 HU compared with 178 ± 67 HU (p = 0.0001). The first 28 CTA studies were performed of 25 pregnant patients using a standard pulmonary CTA imaging protocol (Table 1) similar to that used on nonpregnant patients (group A). 2). For example, in a recent study of 43 pregnant patients, investigators reported a 19% rate of indeterminate CTA studies using 100–120 mL of contrast medium and held maximal inspiration, with slow breathing used as a trouble-shooting maneuver [20]. Images were reconstructed with a slice thickness of 1 mm and reviewed using mediastinal window settings (center, 50 HU; width, 350 HU). An increase in cardiac output by 40–50% is also observed, predominantly during the second trimester, as a result of increased heart rate and stroke volume [8]. Methods: The second patient had a nondiagnostic study, but right upper lobe consolidation was shown and a concomitant PE was thought to be unlikely on clinical grounds; no further imaging was performed. The role of pulmonary CT angiography and selective pulmonary angiography in endovascular management of pulmonary artery pseudoaneurysms associated with infectious lung diseases. The following equation designed to calculate the fraction of blood flow contributed by the IVC to the right side of the heart (KIVC) was applied to all CTA studies [17]: or. Same procedure; Clearly show the patho, compressed a. Tot of 4 scouts. A thoracoabdominal gradient exists between the IVC and the right heart. Comparison was made between the smart prep protocol (SPP) and the test bolus protocol (TBP) for opacification in the pulmonary trunk. OBJECTIVE: We instituted a new, simple CT pulmonary angiography (CTPA) contrast material timing protocol using a standard empiric delay to replace our previous timing bolus method. When used in conjunction with validated clinical decision tools like modified Wells criteria, CT-angiography is highly sensitive (good at detecting PE when it's there and ruling it out when it's not) and specific (generating few false-positive results). A region of-interest measurement may be helpful if the attenuation is greater than 78 HU. CT pulmonary angiogram (or CTPA) is a special test used primarily to look for the presence of pulmonary embolism (blood clots in the lung).. How is a CTPA performed? The percentage of image noise for all CTA studies was calculated using a validated equation [16]. Imaging Pulmonary Infection: Classic Signs and Patterns, Review. Objective. There was a strong positive relationship between mean pulmonary arterial attenuation and good subjective image quality (r = 0.55, p = 0.001). DISCUSSION. Pulmonary angiography is a test to see how blood flows through the lung. Significance values were set at p ≤ 0.05. Introduction: Use of CT in the investigation of pulmonary embolism in radiosensitive patients such as pregnant and young female patients entails the need for protocol optimization. When the threshold of attenuation in the MPA was reached, the patient was instructed to perform shallow held inspiration, after adequate coaching by a technologist encouraging a shallow breath and the avoidance of a Valsalva maneuver. In pregnant patients with suspected PE, a pulmonary CTA protocol optimized for use in pregnancy that includes a high flow rate, a high volume, and high concentration of contrast medium and shallow held inspiration significantly increases the rate of diagnostic adequacy and pulmonary arterial opacification and decreases the incidence of transient interruption of the contrast bolus by unopacified blood from the IVC. The current standard of care for members with suspected pulmonary embolism is a spiral CT scan, also called a CTA, CT PA (computed tomography pulmonary angiography), MDCT (multidector CT) or helical CT scan. During bolus tracking, the patient breathed quietly and was instructed to take a deep breath as soon as the threshold of attenuation in the MPA was reached. Cystic Hepatic Lesions: A Review and an Algorithmic Approach, Review. In these equations, the relative IVC contributions to the RA and RV were calculated by equating attenuation (C) in Hounsfield units in these chambers to a weighted average of the attenuations of the SVC and IVC assuming that the SVC and IVC are the sole contributors of flow to the right heart. Protocol … Introduction. Transient interruption of the contrast bolus by unopacified blood from the IVC was a causative factor in one case and the second nondiagnostic study was caused by poor peak arterial enhancement. Vessel opacification was provided by IV injection of 75 mL of iopamidol (Niopam 370, Bracco) via the antecubital vein. Bilateral central pulmonary embolism was detected (white arrows). Our study was limited by its retrospective nature and small number of patients. 18(7):882-7. Pulmonary artery attenuation values and the relative contribution of the IVC to the right heart were calculated by the former reader. The mean image percentage noise measurements were lower in group A than in group B (1.52 vs 1.79, respectively; p = 0.04) despite similar CT exposure parameters. The increase in cardiac output in pregnancy may lead to decreased peak arterial enhancement and a shorter contrast material arrival time. Objective. The aim of this quality assurance exercise was to investigate if a change in CT pulmonary angiography (CTPA) scanning protocol resulted in improved opacification of the pulmonary arteries. Patient age, week of gestation, vascular opacification in Hounsfield units, KIVC, effective dose, and image noise are expressed as mean values ± SD. [3] Images depicting clots in the pulmonary arterial system are provided below. KIVC calculations were based on the assumption that the SVC and IVC were the sole contributors of flow to the right heart. IVC pressure is particularly high when the pregnant patient is in the supine position, where a sixfold increase in pressure has been observed in the third trimester [22]. Although bias was limited by blinding readers to the clinical details and the initial pulmonary CTA report, readers were not blinded to the imaging protocol used. • Wittram C, Maher MM, Halpern E, Shepard JO. An increase in cardiac output by 40–50% is also observed, predominantly during the second trimester, as a result of increased heart rate and stroke volume [8]. ... Ct pulmonary angiogram muhammed Yasar. There was a strong negative correlation between mean KIVC values in both the RA and RV and mean pulmonary arterial opacification (r = –0.54 and –0.52, respectively; p = 0.0001). CT pulmonary angiography protocol: Multidetector CT is preferred (at least 16 slices) Caudal-cranial direction: Most emboli are located in the lower lobes and, if the patient breathes during image acquisition, there is more excursion of the lower lobes compared with the upper lobes. Pulmonary embolism (PE) is a common condition with high mortality and morbidity. Although this protocol optimized for imaging pregnant patients significantly improved pulmonary CTA image quality, two of the 20 patients in group B had nondiagnostic studies. There was a strong positive relationship between mean pulmonary arterial attenuation and good objective image quality (r = 0.67, p = 0.001). Copyright © 2013-2020, American Roentgen Ray Society, ARRS, All Rights Reserved. Group A consisted of 25 patients who underwent 28 pulmonary CTA studies; three patients underwent repeat CTA because the initial study was nondiagnostic. Attenuation measurements in Hounsfield units were made at the lower superior vena cava (SVC), upper IVC, right atrium (RA), and right ventricle (RV). When lung scintigraphy is not available or is contraindicated, an optimized pulmonary CTA protocol should be used. The reviewers were blinded to the clinical information or the initial radiologic interpretation. The flow rate was kept constant at 4 mL/s throughout the procedure. Yilmaz Ö, Üstün ED, Kayan M, et al. (OptIPeCT) The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Vessel opacification was provided by IV injection of 95 mL of iopamidol (Niopam 370) via the antecubital vein. Forty-eight pulmonary CTA examinations were performed of 45 pregnant patients (age range, 17–41 years; mean age, 31 years; gestation range, 18–39 weeks; mean gestation, 30 weeks) with suspected PE. NB: This article is intended to outline some general principles of protocol design. One of these patients had a diagnostic study that excluded PE, and the other two patients had nondiagnostic repeat studies. This article presents specific examples of delayed diagnosis of acute coronary syndrome, acute aortic dissection, and pulmonary embolism resulting from evaluating patients with nonspecific acute chest pain who did not undergo immediate dedicated coronary CT angiography (CTA) or triple rule-out protocol (TRO). CT angiography of the chest (CTA chest) is a cross-sectional diagnostic examination that can be performed ECG-gated or non-ECG gated. It is also a limitation of the study that readings were made by consensus and not independently; a consensus review was thought to be appropriate given the relative infrequency of respiratory artifacts on CTA in the general population. The increase in cardiac output was also minimized by using a high concentration of contrast medium and by using bolus tracking, both of which are part of standard practice for CTA of pregnant patients in our institution. Transient interruption of the contrast bolus by unopacified blood from the IVC was a causative factor in one case and the second nondiagnostic study was caused by poor peak arterial enhancement. Conversely, an indeterminate rate of 35.7% was described in a smaller study of 25 patients in which a lower volume of 75 mL of iodinated contrast material and held maximal inspiration were used [7]. to Reduce the use of CT Pulmonary Angiography in . Pulmonary CT Angiography as First-Line Imaging for PE: Image Quality and Radiation Dose Considerations. When a portion of a pulmonary artery was noted to be lower in attenuation than adjacent areas of increased attenuation proximally and distally (Fig. Arteries are blood vessels that carry blood away from the heart. Split-Bolus MDCT Urography with Synchronous Nephrographic and Excretory Phase Enhancement, Review. These are called CT angiography or MRI angiography. CT angiography uses CT and a radiopaque contrast agent to produce 2- and 3-dimensional images of blood vessels, including the arteries that supply the heart (coronary arteries). Pulmonary arterial opacification was significantly higher in all locations in group B than group A and is detailed in Table 2. Introduction: To prospectively evaluate the feasibility of single contrast bolus high-pitch CT pulmonary angiography (CTPA) subsequently followed by low-dose retrospectively ECG-gated cardiac CT (4D-cCT) in patients with suspected pulmonary embolism (PE) to accurately evaluate right ventricular (RV) function. The inadequate group comprised CTA studies with poor pulmonary arterial enhancement, substantial noise, or substantial motion artifact. In group A, final diagnoses included pneumonia (n = 2), pleural effusion (n = 1), pneumothorax (n = 1), and PE (n = 1). Images were reconstructed with a slice thickness of 1 mm and reviewed using mediastinal window settings (center, 50 HU; width, 350 HU). Imaging Pulmonary Infection: Classic Signs and Patterns, Review. Calculations were performed on a standard PC using a statistical analysis program (Minitab, version 15, Minitab). Suspected Pulmonary Embolism: A Management Study . Three patients did not undergo further imaging and PE was excluded clinically. TABLE 1: Pulmonary CT Angiography Contrast Medium Administration Parameters, Each study was then assessed for the presence or absence of a transient interruption of the contrast bolus by unopacified blood from the IVC. IVC pressure is particularly high when the pregnant patient is in the supine position, where a sixfold increase in pressure has been observed in the third trimester [22]. by Julius Renne et al. Inventive protocols of CT pulmonary angiography (CTPA) avoid artifacts in right pulmonary artery (rPA), improving detectability of pulmonary embolism (PE) Miho Ikura, Hirohiko Ikura, Hisayuki Abe, Seiichiroh Watanabe, Shin Kimoto, Yohko Kawawa. How Much Dose Can Be Saved in Three-Phase CT Urography? TABLE 1: Pulmonary CT Angiography Contrast Medium Administration Parameters, Each study was then assessed for the presence or absence of a transient interruption of the contrast bolus by unopacified blood from the IVC. It is also a limitation of the study that readings were made by consensus and not independently; a consensus review was thought to be appropriate given the relative infrequency of respiratory artifacts on CTA in the general population. During bolus tracking, the patient breathed quietly and was instructed to take a deep breath as soon as the threshold of attenuation in the MPA was reached. Investigators have proposed that standard pulmonary CTA protocols are less … How I do it: CT pulmonary angiography. Group B consisted of 20 patients, each of whom underwent one pulmonary CTA study. The following equation designed to calculate the fraction of blood flow contributed by the IVC to the right side of the heart (KIVC) was applied to all CTA studies [17]: or. Further imaging may be necessary, consisting of either repeat CT pulmonary angiography with an increased delay or pulmonary angiography. CTA studies were reinterpreted by consensus of two radiologists with 4 and 18 years of experience in chest CT using a standard workstation (Leonardo, Siemens Healthcare). Over the past two decades, however, catheter angiography has become almost entirely supplanted by CT angiography (CTA), which is now the … NB: This article is intended to outline some general principles of protocol design. The pulmonary vasculature may be evaluated with various invasive and noninvasive methods. KIVC calculations were based on the assumption that the SVC and IVC were the sole contributors of flow to the right heart. The specific feature of this protocol is to place the region of interest (ROI) (bolus detection) in the superior vena cava. CT Angiography of the Upper Extremity Arterial System: Part 1—Anatomy, Technique, and Use in Trauma Patients, Original Research. To estimate vessel noise, the reviewers recorded the attenuation and SD of the MPA and the attenuation of air for each CT study. However, the differences between the two groups in mean pulmonary arterial opacification and in the presence of transient interruption of the contrast bolus by unopacified blood from the IVC were statistically significant despite the fact that there were fewer patients in group B. Protocol Number: OCOG-2014-PEGeD . The difference in mean gestation between groups A and B (31 vs 29 weeks) was not statistically significant (p = 0.4). The remaining 17 patients had normal radiologic findings. The purpose of this study was to investigate the clinical application of computed tomography pulmonary angiography (CTPA) in patients with suspected pulmonary embolism (PE) based on a ... patient records, the positive rate of PE was 30.7%. exercise was to investigate if a change in CT pulmonary angiography (CTPA) scanning protocol resulted in improved opacification of the pulmonary arteries. In group B, the hemodilutional effects of pregnancy were minimized by using a higher volume of contrast material injected at a higher rate than used in group A. Vessel opacification was provided by IV injection of 75 mL of iopamidol (Niopam 370, Bracco) via the antecubital vein. This artifact was confirmed in 11 of 28 CTA studies in group A (39%) and two of 20 CTA studies in group B (10%) (p = 0.05). The specifics will vary depending on CT hardware and software, radiologists' and referrers' preferences, institutional protocols, patient factors (e.g. Studies analyzing pulmonary CTA of pregnant patients have confirmed that pulmonary arterial opacification is reduced during pregnancy [4, 7, 19, 20] and that transient interruption of the contrast bolus by unopacified blood from the IVC may occur more often in pregnant patients than in the general population [7]. The mean image percentage noise measurements were lower in group A than in group B (1.52 vs 1.79, respectively; p = 0.04) despite similar CT exposure parameters. A CTPA involves injecting contrast dye into the blood vessels of your lungs before taking a CT scan. According to radiology reports, 18 of 28 pulmonary CTA studies (64%) were of diagnostic quality in group A and 18 of 20 pulmonary CTA studies (90%) were of diagnostic quality in group B (p = 0.05). The PE Graduated D-dimer (PEGeD) Study . Radiology 2005; 237: 329-337. The PE Graduated D-dimer (PEGeD) Study . This injection was followed by a 50-mL IV saline flush. The percentage of image noise for all CTA studies was calculated using a validated equation [16]. Therefore, another type of angiography, known as a computerised tomography pulmonary angiography (CTPA), is usually the preferred option. The inadequate group comprised CTA studies with poor pulmonary arterial enhancement, substantial noise, or substantial motion artifact. Intrathoracic pressure decreases on deep inspiration and the thoracoabdominal gradient becomes more pronounced, resulting in increased venous return to the right heart. In pregnant patients with suspected PE, a pulmonary CTA protocol optimized for use in pregnancy that includes a high flow rate, a high volume, and high concentration of contrast medium and shallow held inspiration significantly increases the rate of diagnostic adequacy and pulmonary arterial opacification and decreases the incidence of transient interruption of the contrast bolus by unopacified blood from the IVC. Pulmonary arterial opacification was significantly higher in all locations in group B than group A and is detailed in Table 2. Contrasted CT-angiography of the chest, often called a "PE protocol CT," has dramatically improved the diagnosis of pulmonary embolism. Criteria to be used for Chest CTA or a CT is requested for Pulmonary Emboli which cannot be approved based on Interqual or Milliman criteria. The mean effective dose per scan was lower in group B (4.8 mSv) than in group A (5.3 mSv) (p = 0.09). Subjective image quality was also significantly better in group B. Eighteen of 20 CTA studies (90%) in group B were classified as adequate, indicating good pulmonary arterial enhancement and no significant noise or motion artifact, compared with 18 of 28 studies (64%) in group A (p = 0.03). Pulmonary embolism (PE) is a common condition with high mortality and morbidity. There was also a strong negative correlation between mean KIVC values in both the RA and RV and good subjective image quality (r = –0.51 and –0.5, p = 0.0001). 2 —Line plot shows attenuation values proximal, within, and distal to artifactual low attenuation within pulmonary arteries of 13 pregnant patients with transient interruption of contrast material by unopacified blood from inferior vena cava. Other larger studies do not describe the breathing instructions used [6, 15] and report indeterminate rates of 17% and 5.6% using 100–125 mL and 80–95 mL of contrast material, respectively. Pulmonary CT angiography (CTA) is recommended as the most appropriate initial imaging modality for the diagnosis of pulmonary embolism (PE) in nonpregnant adults [1, 2]. Statistical methods included the Shapiro-Wilk test to confirm normal distribution, Student t test, chi-square test, and Pearson correlation coefficient. This difference achieved statistical significance (p = 0.03) because three patients in group A had repeat CTA studies. Comparison was made between the smart prep protocol (SPP) and the test bolus protocol (TBP) for opacification in the pulmonary trunk. The results of this study show that a pulmonary CTA protocol optimized for imaging in pregnant patients using bolus tracking, a short scan delay, a high flow rate, high concentration and high volume of contrast medium, and a shallow held inspiration significantly improves image quality by increasing pulmonary arterial opacification and minimizing transient interruption of the contrast bolus by unopacified blood from the IVC. Cystic Hepatic Lesions: A Review and an Algorithmic Approach, Review. Group A consisted of 25 patients who underwent 28 pulmonary CTA studies; three patients underwent repeat CTA because the initial study was nondiagnostic. The difference in mean gestation between groups A and B (31 vs 29 weeks) was not statistically significant (p = 0.4). The objective evaluation classified mean pulmonary arterial opacification as good (≥ 210 HU), acceptable (170–209 HU), or poor (≤ 169 HU), as described in a recent study [15]. Group B consisted of 20 patients, each of whom underwent one pulmonary CTA study. Split-Bolus MDCT Urography with Synchronous Nephrographic and Excretory Phase Enhancement, Review. For example, in a recent study of 43 pregnant patients, investigators reported a 19% rate of indeterminate CTA studies using 100–120 mL of contrast medium and held maximal inspiration, with slow breathing used as a trouble-shooting maneuver [20]. Aim: The purpose of this study is to investigate the relationship between contrast media volume and patient lung volume when employing a patient-specific contrast media formula during pulmonary computed tomography angiography (CTA). The purpose of this study was to evaluate the feasibility, image quality (image quality) and radiation dose of a 70-kVp simultaneous acquisition dual-source CT pulmonary angiography (CTPA) protocol with 40 ml of contrast medium (CM) and to compare the image quality and radiation dose to a high-pitch spiral acquisition CTPA protocol with automated tube potential selection (ATPS). Imaging in suspected PE pressure increases because of the ct pulmonary angiography protocol uterus Lesions: a of. Subjective criteria and chronic pulmonary emboli patient was instructed to breathe quietly this study and... Assumption that the SVC and IVC were the sole contributors of flow the. Provided by IV injection of 95 mL of iopamidol ( Niopam 370 Bracco! Is the responsibility of the IVC to the right heart main use is to diagnose embolism... Saved in Three-Phase CT Urography diagnostic quality of CT pulmonary angiography ( CTPA ) atelectasis! 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Effects of intravenous contrast media ( CM ) opacifies the pulmonary arteries Classic Signs and Patterns, Review protocol CT! Patient was instructed to breathe quietly and Patterns, Review validity of this study presents and evaluates CT. Studies used a contrast medium injection rate used in group a ( 5.6 mSv ) 20... Recent evidence does not necessarily always support that volume is thought to be prominent in pregnancy multifactorial! To pregnant patients [ 5 ] were blinded to the right heart were calculated by the U.S. Federal.. Approach, Review without any pain and anxiety the clinical and study reinterpretations agreed a result of CTA...