RPS 1017 - Pulmonary embolism and other

Purpose:

To evaluate the effects of dose reduction on diagnostic accuracy and image quality of pulmonary angiography CT(CTPA) in adults with suspected pulmonary embolism (PE) in clinical routine.

Methods and materials:

52 consecutive patients received CTPA for suspected PE. Realistic low-dose CT images were generated using an offline software (ReconCT, Siemens Healthineers), as either filter back projections(FBP) or as ADMIRE (strength 3 or 5) with 25%, 50% and 75% of the original dose. To assess image quality (overall image quality, noise, artefacts, and sharpness) and diagnostic confidence, a five-point scale was used. Patient-based and segment-based diagnostic accuracy was calculated for LDCT-reconstruction with original dose CTPA as a standard of reference.

Results:

Among 52 patients, the prevalence of acute pulmonary embolism was moderate (15.5%). The median dose-length product and effective dose for all 52 scans was 275.3±140.5 mGy⋅cm and 3.9±1.9mSV. Overall subjective image quality was highest for ADMIRE 5 with 75% and lowest for FBP with 25% of the original dose (median [interquartile range]:5[5]vs.3[2-3], p<0.001. Patient-based diagnostic accuracy was high for all all LDCT datasets down to 25% for ADMIRE 3+5 (sensitivity:100%, negative predictive value [NPV]: 100%), and lower for FBP with 25% dose reduction (sensitivity: 93%; [NPV]: 97%). Segment-based diagnostic accuracy was high for ADMIRE 3+5 down to 25% dose reduction (sensitivity: 91.9%, specificity: 98.9%) and lowest for FBP with 25% dose reduction (sensitivity: 87.8%, specificity: 99%). Inter-rater agreement regarding the detection of PE was almost perfect at all doses and recons (kappa>0.95).

Conclusion:

Our findings indicate that radiation dose reduction down to 25% of the original data via iterative reconstruction algorithms on a 3rd generation DE-CT scanner maintained the diagnostic accuracy and image quality for the assessment of PE in CTPA.

Limitations:

Retrospective study design.

Ethics committee approval

Approved by the Ethics Committee (University of Tübingen).

Funding:

No funding was received.

Purpose:

The objective was to evaluate the prevalence and determinants of incidental findings (IFs) on MDCTs performed for an emergency department (ED). The secondary aims were to inventory additional investigations, their benefits, side effects, costs and the final diagnoses.

Methods and materials:

One thousand consecutive patients (51.9-year-old +/- 22.7, 477 women) who underwent MDCT in the ED of our institution from January 2011 to November 2011 were retrospectively included. We collected: IFs (divided into low and high clinical significance), body areas covered, availability of prior imaging, radiologist’s experience and subspecialty. In the subgroup of patients followed in our institution, we recorded the additional investigations and their outcomes. Their costs were assessed according to the French health care system.

Results:

Among the 1000 included patients, 232 had at least one IF and 122 at least one IF of high clinical significance (IFCS). A significant association with the presence of at least one IF was noted for the older patient, less-experienced radiologist, no subspecialty of the radiologist, abdominopelvic area, and the absence of prior imaging. In the subgroup of 16 patients followed in our institution, two diagnoses of malignancy were made (a gastro-intestinal stromal tumour and a Bosniak IV cystic renal lesion). One iatrogenic complication occurred (an acute urinary retention following the radiofrequency ablation of the Bosniak IV kidney cyst). Cost of the additional investigations was €41,247 (with an average of €2,578 per patient).

Conclusion:

IFs on emergency MDCTs were frequent, rarely severe, rarely iatrogenic and costly.

Limitations:

The subgroup of patients followed in our institution was small compared to the number of patients included.

Ethics committee approval

This study was approved by our local institutional ethics review board.

Funding:

No funding was received for this work.

Purpose:

The purpose of this study is to explore and to reveal specific structural changes in the aorta and surrounding tissues with CT scans, which can be regarded as signs of aortic wall instability.

Methods and materials:

CT studies were performed by a 160-slice CT scanner with native and arterial contrast phases. CT data of 104 patients with confirmed abdominal aortic aneurysm (AAA) were retrospectively studied. The assessment of such signs of instability of the aortic wall was based on the following findings: hyperattenuating crescent sign, fissuration of parietal thrombotic masses, draped aorta sing, aortic bleb, and periaortic stranding. In addition, the treatment tactics of patients were also studied.

Results:

According to these findings, the patients were divided into 3 groups: 1. with ruptured AAA - in 28 (26.9%) cases. 2. with unruptured AAA, with one sign of instability - in 50 (48%) cases. 10 (20%) patients from this group underwent surgical treatment. 3. with unruptured AAA, with several signs of instability - in 26 (25.1%) cases. In this group, 6 patients underwent urgent surgical treatment, and 4 non-treated patients developed a rupture of AAA in the next few days, i.e. 38.4% of the cases.

Conclusion:

CT can make a quick and comprehensive diagnosis of AAA. The high frequency of occurrence of signs of instability in the ruptured AAA indicates their high prognostic significance. The combination of 2 or more signs indicates a high risk of threatening rupture, which in combination with other factors can be considered as an indication for urgent surgical treatment. The most common CT signs of instability of the AAA include hyperattenuating crescent sign, a draped aorta sing and periaortic stranding.

Limitations:

n/a

Ethics committee approval

n/a

Funding:

No funding was received for this work.

Purpose:

Patients with acute pulmonary embolism (APE) present with a different broad spectrum of prognoses. Computed tomographic pulmonary angiography (CTPA) is the first-line test in APE diagnostic algorithm, but its correlation with short-term outcome remains not clear at all. The aim of this study is to determine if CTPA findings can predict 30-day mortality of patients with APE in the emergency department.

Methods and materials:

This is a retrospective, monocentric study involving 780 patients with APE, diagnosed at the emergency department of our institution between 2010 and 2018. These CTPA findings were evaluated: embolic-obstruction burden score (Qanadli score), common-pulmonary artery trunk diameter, right-to-left ventricular ratio, diameters of the azygos vein and coronary sinus. Comorbidities and fatal/non-fatal adverse outcomes within 30 days were recorded. Troponin I values were investigated and correlated with angiographic parameters with multiple logistic regression analysis.

Results:

The all-cause and APE-related 30-day mortality rates were 5.9% and 3.6% respectively. Patients who died within 30 days were older and had higher prevalence rates of malignancy. Qanadli score and all CTPA parameters correlate with Troponin I level and the presence of RVD at echocardiography (p-values< 0.0001). Instead, RV/LV ratio and coronary sinus diameter correlate with 30-day mortality (p-values< 0.005). At the multivariate-logistic regression analysis, only coronary sinus and RVD remained significant with an HR = 2.5 (95% CI 1.1-5.6) and HR = 1.9 (95% CI 0.95-3.7), respectively.

Conclusion:

These results suggest that CTPA quantification of right ventricular strain is an accurate predictor of 30-day mortality. In particular, it seems that a dilated coronary sinus (> 9 mm) has an additional prognostic value in association with echocardiographic signs of right-heart disfunction and high Troponin I levels.

Limitations:

n/a

Ethics committee approval

Approval for this study is in progress.

Funding:

n/a

Purpose:

Aim of this study was to evaluate the performance of a computer-assisted detection algorithm (CAD) for the diagnosis of peripheral pulmonary embolism (PE) using a reduced contrast material dose CT acquisition protocol.

Methods and materials:

Retrospective analysis of patients referred to CT for assessment of PE from July 2018 to December 2018. Patients with evidence of central PE at CT were excluded. CT pulmonary angiograms were obtained using a dual-layer detector CT and an injection technique comprising 55 ml contrast material (iodine concentration, 350 mg/ml) and 50 ml saline chaser with 4 ml/s flow rate. PE-CAD was performed using a dedicated image processing software designed for peripheral PE detection (Philips Intellispace Portal version 10, Haifa, Israel). Test performance statistics were calculated for PE-CAD detection of peripheral emboli with a radiologists’ read serving as reference standard.

Results:

130 patients were included. 21 patients with 151 peripheral emboli were diagnosed with peripheral PE using the reference standard. 20 patients with peripheral PE were correctly identified by PE-CAD. PE-CAD was false positive in 46 patients without a final diagnosis of peripheral PE. On a per-patient basis, sensitivity, specificity, negative likelihood ratio, and positive likelihood ratio for PE-CAD were 95%, 58%, 0.08 and 2.26, respectively. On a per-embolus basis, sensitivity, specificity, negative likelihood ratio, and positive likelihood ratio for PE-CAD were 60%, 33%, 1.22, and 0.89, respectively.

Conclusion:

Using a reduced contrast material dose CT acquisition protocol, PE-CAD is valuable for the exclusion of peripheral PE on a per-patient basis. Use of PE-CAD as a screening tool is limited by false positive findings.

Limitations:

n/a

Ethics committee approval

n/a

Funding:

n/a

Purpose:

To evaluate the efficiency and impact of computerized tomography (CT) on diagnosis and further diagnostic/therapeutic regimen in ICU patients with fever, systemic inflammatory response syndrome (SIRS) or sepsis with unknown focus of infection.

Methods and materials:

Non-ECG-gated chest/abdominal CT examinations of ICU patients (internal medicine, surgery, heart surgery, neurology/neurosurgery) were prospectively analyzed for inflammatory foci. Both CT findings and changes in diagnostic/therapeutic regimen were analyzed. Prior CT, X-Ray, MRI, ultrasound examinations, bronchioalveolar lavage and urine analysis performed during the same ICU treatment but prior to the CT, were cross-checked to verify whether foci were actually new.

Results:

In 99 out of 112 (88,4%) prospectively examined patients (34,8% female, mean age 64,8 years), a total of 147 possible foci (thoracic: n=92; abdominal: n=55) were detected. Of the 147 foci (58,5% defined as definite, 41,5% as questionable), prior examinations had suspected inflammatory focus in 80 cases. CT diagnosis led to 74 changes in therapy regimen in 58 of 99 Patients (59%): change/initiation of antibiotics: 52,7%, CT guided thoracic/abdominal puncture: 21,6%, operation: 8,1%, change in patient positioning: 8,1%; other: 9,5%. In 24 patients, CT findings led to 33 diagnostic follow-ups: endoscopy: 45,5%, microbiological testing: 24,2%, additional imaging: 18,2%, others: 12,1%.

Conclusion:

CT examinations in ICU patients with unknown focus of infection leads to diagnosis in most cases as well as to adaption in therapy regimen and thus should be considered in patients with obscure clinical infection.

Limitations:

Further research has to be done with a higher number of CTs and patients to outline the specific role and impact of CT in patients of unknown Focus of Infection.

Ethics committee approval

The Ethics Committee of the University Clinic of Bonn approved the study.

Funding:

No funding was received for this work.