Pneumonia pattern recognition on ultra-low-dose CT does not allow for a reliable differentiation between viral and bacterial pneumonia: A multicentre observer study.

PURPOSE: While a reliable differentiation between viral and bacterial pneumonia is not possible with chest X-ray, this study investigates whether ultra-low-dose chest-CT (ULDCT) could be used for this purpose. METHODS: In the OPTIMACT trial 281 patients had a final diagnosis of pneumonia, and 96/281 (34%) had one or more positive microbiology results: 60 patients viral pathogens, 48 patients bacterial pathogens. These 96 ULDCT's were blindly and independently evaluated by two chest radiologists, who reported CT findings, pneumonia pattern, and most likely type of pathogen. Differences between groups were analysed for each radiologist separately, diagnostic accuracy was evaluated by calculating sensitivity. RESULTS: The dominant CT finding significantly differed between the viral and bacterial pathogen groups (p = 0.04; p = 0.04). Consolidation was the most frequent dominant CT finding in both patients with viral and bacterial pathogens, but was observed significantly more often in those with a bacterial pathogen: 32/60 and 22/60 versus 38/48 and 31/48 (p = 0.005; p = 0.004). The lobar pneumonia pattern was more frequently observed in patients with a bacterial pathogen: 23/48 and 18/48, versus 10/60 and 8/60 for viral pathogens (p < 0.001; p = 0.004). For the bronchopneumonia and interstitial pneumonia patterns the proportions of viral and bacterial pathogens were not significantly different. Both radiologists suggested a viral pathogen correctly (sensitivity) in 6/60 (10%), for a bacterial pathogen this was 34/48 (71%). CONCLUSION: Reliable differentiation between viral and bacterial pneumonia could not be made by pattern recognition on ULDCT, although a lobar pneumonia pattern was significantly more often observed in bacterial infection.

The yield of chest X-ray or ultra-low-dose chest-CT in emergency department patients suspected of pulmonary infection without respiratory symptoms or signs.

OBJECTIVE: The yield of pulmonary imaging in patients with suspected infection but no respiratory symptoms or signs is probably limited, ultra-low-dose CT (ULDCT) is known to have a higher sensitivity than Chest X-ray (CXR). Our objective was to describe the yield of ULDCT and CXR in patients clinically suspected of infection, but without respiratory symptoms or signs, and to compare the diagnostic accuracy of ULDCT and CXR. METHODS: In the OPTIMACT trial, patients suspected of non-traumatic pulmonary disease at the emergency department (ED) were randomly allocated to undergo CXR (1210 patients) or ULDCT (1208 patients). We identified 227 patients in the study group with fever, hypothermia, and/or elevated C-reactive protein (CRP) but no respiratory symptoms or signs, and estimated ULDCT and CXR sensitivity and specificity in detecting pneumonia. The final day-28 diagnosis served as the clinical reference standard. RESULTS: In the ULDCT group, 14/116 (12%) received a final diagnosis of pneumonia, versus 8/111 (7%) in the CXR group. ULDCT sensitivity was significantly higher than that of CXR: 13/14 (93%) versus 4/8 (50%), a difference of 43% (95% CI: 6 to 80%). ULDCT specificity was 91/102 (89%) versus 97/103 (94%) for CXR, a difference of - 5% (95% CI: - 12 to 3%). PPV was 54% (13/24) for ULDCT versus 40% (4/10) for CXR, NPV 99% (91/92) versus 96% (97/101). CONCLUSION: Pneumonia can be present in ED patients without respiratory symptoms or signs who have a fever, hypothermia, and/or elevated CRP. ULDCT's sensitivity is a significant advantage over CXR when pneumonia has to be excluded. CLINICAL RELEVANCE STATEMENT: Pulmonary imaging in patients with suspected infection but no respiratory symptoms or signs can result in the detection of clinically significant pneumonia. The increased sensitivity of ultra-low-dose chest CT compared to CXR is of added value in vulnerable and immunocompromised patients. KEY POINTS: • Clinical significant pneumonia does occur in patients who have a fever, low core body temperature, or elevated CRP without respiratory symptoms or signs. • Pulmonary imaging should be considered in patients with unexplained symptoms or signs of infections. • To exclude pneumonia in this patient group, ULDCT's improved sensitivity is a significant advantage over CXR.

Ultra-low-dose CT versus chest X-ray for patients suspected of pulmonary disease at the emergency department: a multicentre randomised clinical trial.

BACKGROUND: Chest CT displays chest pathology better than chest X-ray (CXR). We evaluated the effects on health outcomes of replacing CXR by ultra-low-dose chest-CT (ULDCT) in the diagnostic work-up of patients suspected of non-traumatic pulmonary disease at the emergency department. METHODS: Pragmatic, multicentre, non-inferiority randomised clinical trial in patients suspected of non-traumatic pulmonary disease at the emergency department. Between 31 January 2017 and 31 May 2018, every month, participating centres were randomly allocated to using ULDCT or CXR. Primary outcome was functional health at 28 days, measured by the Short Form (SF)-12 physical component summary scale score (PCS score), non-inferiority margin was set at 1 point. Secondary outcomes included hospital admission, hospital length of stay (LOS) and patients in follow-up because of incidental findings. RESULTS: 2418 consecutive patients (ULDCT: 1208 and CXR: 1210) were included. Mean SF-12 PCS score at 28 days was 37.0 for ULDCT and 35.9 for CXR (difference 1.1; 95% lower CI: 0.003). After ULDCT, 638/1208 (52.7%) patients were admitted (median LOS of 4.8 days; IQR 2.1-8.8) compared with 659/1210 (54.5%) patients after CXR (median LOS 4.6 days; IQR 2.1-8.8). More ULDCT patients were in follow-up because of incidental findings: 26 (2.2%) versus 4 (0.3%). CONCLUSIONS: Short-term functional health was comparable between ULDCT and CXR, as were hospital admissions and LOS, but more incidental findings were found in the ULDCT group. Our trial does not support routine use of ULDCT in the work-up of patients suspected of non-traumatic pulmonary disease at the emergency department. TRIAL REGISTRATION NUMBER: NTR6163.

[Unusual findings on chest x-ray]. / Afwijkingen op een thoraxfoto.

We describe a 59-year-old woman, who came to the Emergency Room with fever, dyspnoea and lung abnormalities on chest x-ray. The X-ray abnormalities were not related to the clinical symptoms and could be explained by the patient's medical history, which included rib fractures and spinal compression fractures. The confined spherical structures visible on chest X-ray were indicative of previous rib fractures. The linear hyperdense branching structures represent diffuse pulmonary cement embolisms after percutaneous vertebroplasty.

OPTimal IMAging strategy in patients suspected of non-traumatic pulmonary disease at the emergency department: chest X-ray or ultra-low-dose CT (OPTIMACT)-a randomised controlled trial chest X-ray or ultra-low-dose CT at the ED: design and rationale.

BACKGROUND: Chest X-ray has been the standard imaging method for patients suspected of non-traumatic pulmonary disease at the emergency department (ED) for years. Recently, ultra-low-dose chest computed tomography (ULD chest CT) has been introduced, which provides substantially more detailed information on pulmonary conditions that may cause pulmonary disease, with a dose in the order of chest X-ray (0.1 vs. 0.05 mSv). The OPTimal IMAging strategy in patients suspected of non-traumatic pulmonary disease at the emergency department: chest X-ray or CT (OPTIMACT) study is a randomized trial designed to evaluate the effectiveness of replacing chest X-ray for ULD chest CT in the diagnostic work-up of patients suspected of non-traumatic pulmonary disease at the ED. METHODS: Two thousand four hundred patients presenting at the ED with pulmonary complaints and suspected of non-traumatic pulmonary disease will be enrolled in this multicenter, pragmatic, randomized trial. During randomly assigned periods of one calendar month, either conventional chest X-ray or ULD chest CT scan will be used as the imaging strategy. Randomization will rely on computer-generated blocks of 2 months to control for seasonal effects. Chest X-ray and ULD chest CT will be performed in a standardized way, after obtaining the clinical history and performing physical examination and initial laboratory tests. The primary outcome measure is functional health at 28 days. Secondary outcome measures are mental health, length of hospital stay, mortality within 28 days, quality-adjusted life years (QALYs) during the first 28 days, correct diagnoses at ED discharge as compared to the final post hoc diagnosis, and number of patients in follow-up because of incidental findings on chest X-ray or ULD chest CT. In an economic evaluation, we will estimate total health care costs during the first 28 days. DISCUSSION: This pragmatic trial will clarify the effects of replacing chest X-ray by ULD chest CT in daily practice, in terms of patient-related health outcomes and costs, in the diagnostic work-up of patients suspected of non-traumatic pulmonary disease at the ED. TRIAL REGISTRATION: The OPTIMACT trial is registered in the Netherlands National Trial Register under number NTR6163. The date of registration is December 6, 2016.

Primary uncleansed 2D versus primary electronically cleansed 3D in limited bowel preparation CT-colonography. Is there a difference for novices and experienced readers?

The purpose of this study was to compare a primary uncleansed 2D and a primary electronically cleansed 3D reading strategy in CTC in limited prepped patients. Seventy-two patients received a low-fibre diet with oral iodine before CT-colonography. Six novices and two experienced observers reviewed both cleansed and uncleansed examinations in randomized order. Mean per-polyp sensitivity was compared between the methods by using generalized estimating equations. Mean per-patient sensitivity, and specificity were compared using the McNemar test. Results were stratified for experience (experienced observers versus novice observers). Mean per-polyp sensitivity for polyps 6 mm or larger was significantly higher for novices using cleansed 3D (65%; 95%CI 57-73%) compared with uncleansed 2D (51%; 95%CI 44-59%). For experienced observers there was no significant difference. Mean per-patient sensitivity for polyps 6 mm or larger was significantly higher for novices as well: respectively 75% (95%CI 70-80%) versus 64% (95%CI 59-70%). For experienced observers there was no statistically significant difference. Specificity for both novices and experienced observers was not significantly different. For novices primary electronically cleansed 3D is better for polyp detection than primary uncleansed 2D.

Frequency of the TAFI -438 G/A and factor XIIIA Val34Leu polymorphisms in patients with objectively proven pulmonary embolism.

Deep vein thrombosis (DVT) and pulmonary embolism (PE) are considered to be two forms of the same disease, however it is not fully understood what determines their clinical presentation. Proteins encoded by the FXIIIA and TAFI genes are involved in stabilizing the fibrin clot and in making it more lysis resistant. The FXIIIA 34Leu and TAFI -438A alleles might protect against DVT. Information on such an association with PE is either contradictory or missing. We hypothesized that both polymorphisms might influence the formation and fate of emboli and accordingly the risk of PE. We determined the frequencies of both polymorphisms in patients with objectively demonstrated PE. The frequency of FXIIIA Leu34Leu in PE patients and non-PE patients was 4.5% and 8.8%, [OR 0.5 (95% CI: 0.1 to 1.9)], respectively. For -438 A/A TAFI genotype the frequency was 1.5% and 8.1% [OR 0.1 (95% CI: 0.02 to 1.1)], respectively.

Diagnosis of pulmonary embolism with spiral CT as a second procedure following scintigraphy.

Our objective was to evaluate, in a routine clinical setting, the role of spiral CT as a second procedure in patients with clinically suspected pulmonary embolism (PE) and abnormal perfusion scan. We prospectively studied the role of spiral CT in 279 patients suspected of PE. All patients started their diagnostic algorithm with chest radiographs and perfusion scintigraphy. Depending on the results of perfusion scintigraphy, patients proceeded to subsequent levels in the algorithm: stop if perfusion scintigraphy was normal; CT and pulmonary angiography if subsegmental perfusion defects were seen; ventilation scintigraphy followed by CT when segmental perfusion defects were seen; and pulmonary angiography in this last group when results of ventilation/perfusion scintigraphy and CT were incongruent. Reference diagnosis was based on normal perfusion scintigraphy, high probability perfusion/ventilation scintigraphy in combination with abnormal CT, or pulmonary angiography. If PE was present, the largest involved branch was noted on pulmonary angiography, or on spiral CT scan in case of a high-probability ventilation/perfusion scan and a positive CT scan. A distinction was made between embolism in a segmental branch or larger, or subsegmental embolism. Two hundred seventy-nine patients had abnormal scintigraphy. In 27 patients spiral CT and/or pulmonary angiography were non-diagnostic and these were excluded for image analysis. Using spiral CT we correctly identified 117 of 135 patients with PE, and 106 of 117 patients without PE. Sensitivity and specificity was therefore 87 and 91%, respectively. Prevalence of PE was 53%. Positive and negative predictive values were, respectively, 91 and 86%. In the high-probability group, sensitivity and specificity increased to 97 and 100%, respectively, with a prevalence of 90%. In the non-high probability-group sensitivity and specificity decreased to 61 and 89%, respectively, with a prevalence of 25%. In a routine clinical setting single-detector spiral CT technology has limited value as a second diagnostic test because of low added value in patients with a high-probability lung scan and low sensitivity in patients with non-high-probability lung scan result.

Single-detector helical computed tomography as the primary diagnostic test in suspected pulmonary embolism: a multicenter clinical management study of 510 patients.

BACKGROUND: Helical computed tomography (CT) is a readily available tool for diagnosing pulmonary embolism (PE); however, its role in the management of patients with clinically suspected PE has not been fully established. OBJECTIVE: To determine the effectiveness and safety of using helical CT of the pulmonary arteries as the primary diagnostic test in patients with suspected PE. DESIGN: Multicenter, prospective clinical outcome study. SETTING: Two academic hospitals and one large teaching hospital in the Netherlands. PATIENTS: 510 consecutive inpatients and outpatients with clinically suspected PE followed for 3 months. INTERVENTIONS: Patients underwent helical CT of the pulmonary arteries within 24 hours after presenting with signs and symptoms of PE. If CT results were normal or inconclusive, compression ultrasonography was performed on the same day as CT and repeated on days 4 and 7 if findings on the first compression ultrasonography were normal. When CT or compression ultrasonography results were positive for thromboembolism, anticoagulation was started. Anticoagulation was not started when results of CT were negative for PE or indicated an alternative diagnosis that explained the clinical signs and symptoms, or when results on serial compression ultrasonography were normal. MEASUREMENTS: Patients received instructions to report any symptoms or signs of PE or deep venous thrombosis (DVT) during the 3-month follow-up period. The authors performed compression ultrasonography or phlebography for suspected DVT and pulmonary angiography for suspected PE. RESULTS: Computed tomography identified PE in 124 of 510 patients (24.3%) and an alternative diagnosis in 130 patients (25.5%); CT scans were normal in 248 patients (48.6%). The CT scan could not be interpreted in 8 patients (1.6%) and was not obtained in 2. Compression ultrasonography revealed DVT in 2 patients at the first examination; findings on repeated compression ultrasonography at days 4 and 7 were normal. Mortality in the patients with normal helical CT scans was 4.1% (10 of 246 patients). No patients in this group died of fatal PE, 1 patient developed nonfatal PE, and venous thromboembolism occurred in 0.4% of these patients (95% CI, 0% to 2.2%). In the patients with alternative diagnoses, 1 patient had DVT on objective testing during follow-up. Mortality in this group was 21.5% (28 of 130 patients); in 1 of these patients, PE could not be confidently ruled out as a contributing cause of death. Venous thromboembolism occurred in 1.5% of these patients (CI, 0.2% to 5.6%). CONCLUSIONS: In patients with suspected PE, helical CT can be used safely as the primary diagnostic test to rule out PE. Serial compression ultrasonography has limited additional value.

Embolus location affects the sensitivity of a rapid quantitative D-dimer assay in the diagnosis of pulmonary embolism.

D-dimer blood tests have been suggested to rule out pulmonary embolism. Despite evidence of the safety of withholding anticoagulant treatment in patients with suspected pulmonary embolism and a normal D-dimer assay result, clinicians remain reluctant to use a D-dimer assay as a sole diagnostic test. This prospective study in 314 consecutive inpatients and outpatients investigates the relation between the diagnostic accuracy of D-dimer plasma concentration and pulmonary embolus location. Plasma D-dimer levels were measured using a quantitative immunoturbidimetric method. A strict protocol of ventilation-perfusion scintigraphy, pulmonary angiography, and spiral computed tomography was used to arrive at a final diagnosis and to assess the largest pulmonary artery in which embolus was visible. The influence of embolus location on the diagnostic accuracy was evaluated using the Kruskal-Wallis test and receiver operator characteristics (ROC) analysis. There was a strong correlation between plasma D-dimer concentration and embolus location (Kruskal-Wallis, p < 0.001). Thus, the assay showed greater accuracy in excluding segmental or larger emboli (sensitivity = 93%) than subsegmental emboli (sensitivity = 50%). D-dimer concentration and the accuracy of D-dimer assays are clearly dependent on embolus location and smaller, subsegmental emboli may be missed when D-dimer assays are used as a sole test to exclude pulmonary embolism.

Optimal scan delay in spiral CT for the diagnosis of acute pulmonary embolism.

PURPOSE: The purpose of this work was to assess whether easily obtained clinical parameters can predict optimal scan delay for contrast-enhanced spiral CT of pulmonary arteries and to compare image quality between individualized contrast timing versus a fixed scan delay. METHOD: We used an individualized delay in 85 patients by measuring the contrast transit time through the pulmonary circulation (Group A) and assessed the correlation between transit time and clinical parameters. In 56 patients (Group B), we used a 20 s fixed scan delay. The CT examinations of both groups were compared with regard to image quality. RESULTS: Contrast transit times (mean 10.5 s, range 4-26 s) did not correlate significantly with heart rate, blood pressure, body length, weight, body surface area, or cardiac function. Although contrast transit times were significantly related to gender and age, only 14.8% of the variation could be explained by these clinical parameters. Data of 57 patients in Group A and 50 patients in Group B were available for analysis. Image quality was not significantly different between Groups A and B, which was good, moderate, and poor in 61, 32, and 7% in Group A and 60, 34, and 6% in Group B, respectively (p = 1.0). CONCLUSION: One cannot predict individual scan delay from easily obtainable clinical parameters. Fortunately, a 20 s fixed scan delay provides equal image quality as individualized contrast timing.

The performance of two rapid quantitative D-dimer assays in 287 patients with clinically suspected pulmonary embolism.

CONTEXT: Objective tests are necessary for the diagnosis of pulmonary embolism (PE). D-dimer assays have been suggested as useful screening tests to exclude this diagnosis. OBJECTIVE: To compare the diagnostic accuracy of two rapid quantitative D-dimers in patients with suspected pulmonary embolism. DESIGN: Plasma D-dimer levels were measured using two commercially available assays (Tinaquant and Vidas). A strict imaging protocol was used to arrive at a final diagnosis of PE or deep venous thrombosis (DVT). SETTING: Multicenter study in six Dutch referral centers. PATIENTS: A total of 287 in- and outpatients with clinically suspected pulmonary embolism. MAIN OUTCOME MEASURES: Diagnostic accuracy indices for the two assays were calculated and additional receiver-operated characteristics (ROC) analysis was performed. RESULTS: Using the manufacturer's advised cutoff values, the sensitivity and specificity were 88% and 52% for Vidas and 82% and 61% for Tinaquant, respectively. These differences were statistically significant (McNemar, P < 0.0001). However, no statistical differences were found between the two assays using ROC analysis (AUC = 0.78 for both assays). CONCLUSIONS: Both quantitative D-dimer tests had similar diagnostic accuracy; however, at the manufacturer's advised cutoff level, Vidas performed significantly better. Nevertheless, to safely exclude pulmonary embolism, D-dimer assays should be combined with other diagnostic tests.