Delayed Diagnosis of Pulmonary Artery Thrombosis in a Patient Undergoing Mitral Valve Replacement.

ABSTRACT: The occurrence of pulmonary artery thrombus in association with rheumatic mitral stenosis is a rare complication. Pulmonary artery thrombus formation may worsen pulmonary artery pressures, and this may precipitate acute right heart failure. The possible mechanisms behind pulmonary artery thrombus formation during mitral valve replacement surgery could be acute coagulopathy following surgery, the presence of chronic pulmonary thromboembolism, or chronic atrial fibrillation. We report an unusual case of pulmonary artery thrombus in a patient with rheumatic MS which was diagnosed with transoesophageal echocardiography after MVR.

Evaluation and Utilization of Flow Artifacts at CT.

Flow artifacts are commonly encountered at contrast-enhanced CT and can be difficult to discern from true pathologic conditions. Therefore, radiologists must be comfortable distinguishing flow artifacts from true pathologic conditions. This is of particular importance when evaluating the pulmonary arteries and aorta, as a flow artifact may be mistaken for a pulmonary embolism or dissection flap. Understanding the mechanics of flow artifacts and how these artifacts are created can help radiologists in several ways. First, this knowledge can help radiologists appreciate how the imaging characteristics of flow artifacts differ from true pathologic conditions. This information can also help radiologists better recognize the clinical conditions that predispose patients to flow artifacts, such as pneumonia, chronic lung damage, and altered cardiac output. By understanding when flow artifacts may be confounding the interpretation of an examination, radiologists can then know when to pursue other troubleshooting methods to assist with the diagnosis. In these circumstances, the radiologist can consider several troubleshooting methods, including adjusting the imaging protocols, recommending when additional imaging may be helpful, and suggesting which imaging study would be the most beneficial. Finally, flow artifacts can also be used as a diagnostic tool when evaluating the vascular anatomy, examples of which include the characterization of shunts, venous collaterals, intimomedial flaps, and alternative patterns of blood flow, as seen in extracorporeal membrane oxygenation circuits. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Anatomically aware dual-hop learning for pulmonary embolism detection in CT pulmonary angiograms.

Pulmonary Embolisms (PE) represent a leading cause of cardiovascular death. While medical imaging, through computed tomographic pulmonary angiography (CTPA), represents the gold standard for PE diagnosis, it is still susceptible to misdiagnosis or significant diagnosis delays, which may be fatal for critical cases. Despite the recently demonstrated power of deep learning to bring a significant boost in performance in a wide range of medical imaging tasks, there are still very few published researches on automatic pulmonary embolism detection. Herein we introduce a deep learning based approach, which efficiently combines computer vision and deep neural networks for pulmonary embolism detection in CTPA. Our method brings novel contributions along three orthogonal axes: (1) automatic detection of anatomical structures; (2) anatomical aware pretraining, and (3) a dual-hop deep neural net for PE detection. We obtain state-of-the-art results on the publicly available multicenter large-scale RSNA dataset.

Influencing factors on the time to CT in suspected pulmonary embolism: an explorative investigation.

Pulmonary embolism is a potentially fatal condition with increased mortality if anticoagulation is delayed. This study aimed to find influencing factors on the duration from requesting a computed tomography (CT) pulmonary angiography (CTPA) to performing a CTPA in suspected acute pulmonary embolism. In 1849 cases, automatically generated time data were extracted from the radiological information system. The impact of the distance to the scanner, case-related features (sector of patient care, triage), and workload (demand for CTs, performed CTs, available staff, hospital occupancy) were investigated retrospectively using multiple regression. The time to CTPA was shorter in cases from the emergency room (ER) than in inpatients and outpatients at distances below 160 m and 240 m, respectively. While requests from the ER were also performed faster than cases from regular wards (< 180 m), no difference was found between the ER and intensive care units. Compared to "not urgent" cases, the workflow was shorter in "urgent" (- 17%) and "life-threatening" (- 67%) situations. The process was prolonged with increasing demand (+ 5%/10 CTs). The presented analysis identified relevant in-hospital influences on the CTPA workflow, including the distance to the CT together with the sector of patient care, the case triage, and the demand for imaging.

Effects of right ventricular remodeling in chronic thromboembolic pulmonary hypertension on the outcomes of balloon pulmonary angioplasty: a 2D-speckle tracking echocardiography study.

BACKGROUND: Balloon pulmonary angioplasty (BPA) improves the prognosis of chronic thromboembolic pulmonary hypertension (CTEPH). Right ventricle (RV) is an important predictor of prognosis in CTEPH patients. 2D-speckle tracking echocardiography (2D-STE) can evaluate RV function. This study aimed to evaluate the effectiveness of BPA in CTEPH patients and to assess the value of 2D-STE in predicting outcomes of BPA. METHODS: A total of 76 patients with CTEPH underwent 354 BPA sessions from January 2017 to October 2022. Responders were defined as those with mean pulmonary artery pressure (mPAP) ≤ 30 mmHg or those showing ≥ 30% decrease in pulmonary vascular resistance (PVR) after the last BPA session, compared to baseline. Logistic regression analysis was performed to identify predictors of BPA efficacy. RESULTS: BPA resulted in a significant decrease in mPAP (from 50.8 ± 10.4 mmHg to 35.5 ± 11.9 mmHg, p < 0.001), PVR (from 888.7 ± 363.5 dyn·s·cm-5 to 545.5 ± 383.8 dyn·s·cm-5, p < 0.001), and eccentricity index (from 1.3 to 1.1, p < 0.001), and a significant increase in RV free wall longitudinal strain (RVFWLS: from 15.7% to 21.0%, p < 0.001). Significant improvement was also observed in the 6-min walking distance (from 385.5 m to 454.5 m, p < 0.001). After adjusting for confounders, multivariate analysis showed that RVFWLS was the only independent predictor of BPA efficacy. The optimal RVFWLS cutoff value for predicting BPA responders was 12%. CONCLUSIONS: BPA was found to reduce pulmonary artery pressure, reverse RV remodeling, and improve exercise capacity. RVFWLS obtained by 2D-STE was an independent predictor of BPA outcomes. Our study may provide a meaningful reference for interventional therapy of CTEPH.

Development and web deployment of prediction model for pulmonary arterial pressure in chronic thromboembolic pulmonary hypertension using machine learning.

BACKGROUND AND PURPOSE: Mean pulmonary artery pressure (mPAP) is a key index for chronic thromboembolic pulmonary hypertension (CTEPH). Using machine learning, we attempted to construct an accurate prediction model for mPAP in patients with CTEPH. METHODS: A total of 136 patients diagnosed with CTEPH were included, for whom mPAP was measured. The following patient data were used as explanatory variables in the model: basic patient information (age and sex), blood tests (brain natriuretic peptide (BNP)), echocardiography (tricuspid valve pressure gradient (TRPG)), and chest radiography (cardiothoracic ratio (CTR), right second arc ratio, and presence of avascular area). Seven machine learning methods including linear regression were used for the multivariable prediction models. Additionally, prediction models were constructed using the AutoML software. Among the 136 patients, 2/3 and 1/3 were used as training and validation sets, respectively. The average of R squared was obtained from 10 different data splittings of the training and validation sets. RESULTS: The optimal machine learning model was linear regression (averaged R squared, 0.360). The optimal combination of explanatory variables with linear regression was age, BNP level, TRPG level, and CTR (averaged R squared, 0.388). The R squared of the optimal multivariable linear regression model was higher than that of the univariable linear regression model with only TRPG. CONCLUSION: We constructed a more accurate prediction model for mPAP in patients with CTEPH than a model of TRPG only. The prediction performance of our model was improved by selecting the optimal machine learning method and combination of explanatory variables.

Optimization of CT pulmonary angiography for pulmonary embolism using task-based image quality assessment and diagnostic reference levels: A multicentric study.

PURPOSE: To establish size-specific diagnostic reference levels (DRLs) for pulmonary embolism (PE) based on patient CT examinations performed on 74 CT devices. To assess task-based image quality (IQ) for each device and to investigate the variability of dose and IQ across different CTs. To propose a dose/IQ optimization. METHODS: 1051 CT pulmonary angiography dose data were collected. DRLs were calculated as the 75th percentile of CT dose index (CTDI) for two patient categories based on the thoracic perimeters. IQ was assessed with two thoracic phantom sizes using local acquisition parameters and three other dose levels. The area under the ROC curve (AUC) of a 2 mm low perfused vessel was assessed with a non-prewhitening with eye-filter model observer. The optimal IQ-dose point was mathematically assessed from the relationship between IQ and dose. RESULTS: The DRLs of CTDIvol were 6.4 mGy and 10 mGy for the two patient categories. 75th percentiles of phantom CTDIvol were 6.3 mGy and 10 mGy for the two phantom sizes with inter-quartile AUC values of 0.047 and 0.066, respectively. After the optimization, 75th percentiles of phantom CTDIvol decreased to 5.9 mGy and 7.55 mGy and the interquartile AUC values were reduced to 0.025 and 0.057 for the two phantom sizes. CONCLUSION: DRLs for PE were proposed as a function of patient thoracic perimeters. This study highlights the variability in terms of dose and IQ. An optimization process can be started individually and lead to a harmonization of practice throughout multiple CT sites.

Low left ventricular outflow tract velocity time integral predicts normotensive shock in patients with acute pulmonary embolism.

In this study, we found that a low LVOT VTI (<15 cm), a simple bedside point-of-care measurement, predicts normotensive shock in patients with acute intermediate-risk PE.

[A case of right heart failure: when it is not pulmonary embolism]. / Un caso di insufficienza cardiaca destra: quando l'embolia polmonare non è un'embolia polmonare.

A 66-year-old patient with recent instrumental findings (echocardiogram, cardiac magnetic resonance imaging) of right ventricular failure was hospitalized due to worsening signs and symptoms of right heart failure, while waiting for diagnostic definition. Pulmonary computed tomography angiography revealed findings compatible with bilateral pulmonary thromboembolism involving the main pulmonary artery. Anticoagulant therapy was initiated with initial benefit, partial relief of symptoms, and moderate improvement in right ventricular function. However, after 4 weeks, the patient was readmitted for recurrence of heart failure and signs of low cardiac output. Echocardiography showed the presence of a conspicuous, mobile, isoechoic mass occupying much of the main pulmonary artery, once again suggestive of thrombosis. The patient underwent surgical thromboendoarterectomy; postoperatively, the procedure was complicated by severe refractory heart failure unresponsive to pharmacological treatments and mechanical support, leading to death in the subsequent days. Unexpectedly, histological analysis revealed a primary angiosarcoma of the endothelium of the main pulmonary artery, a very rare cause of pulmonary artery obstruction generally associated with worst prognosis and presenting with clinical features similar to pulmonary thromboembolism.

Retrieval of an inferior vena cava Greenfield filter 34 years after insertion.

Inferior vena cava (IVC) filters are engineered medical devices deployed in the IVC primarily to prevent a pulmonary embolism from occurring. In this article, we present a case of an IVC filter that was successfully retrieved from a patient after being in place for 34 years. The patient presented to hospital for trauma in which subsequent imaging showed tines of an IVC filter protruding outside of the vessel with one of the tines penetrating the duodenal wall. The filter was successfully removed with no complications. This report adds to the existing literature by yielding an example of an adverse risk that can be associated with the placement of IVC filters. In addition, to the authors' best knowledge, this is the longest reported length of time that an IVC filter has stayed in a patient before being removed, thus adding another intriguing detail to the case.

Ultrasound-Assisted Catheter-Directed Thrombolysis for the Management of Pulmonary Embolism: A Single Center Experience in a Community Hospital.

Current guidelines recommend anticoagulation alone for low-risk pulmonary embolism (PE) with the addition of systemic thrombolysis for high-risk PE. However, treatment recommendations for intermediate-risk PE are not well-defined. Due to bleeding risks associated with systemic thrombolysis, ultrasound-assisted catheter-directed thrombolysis (USAT) has evolved as a promising treatment modality. USAT is thought to decrease the rate of major bleeding by using localized delivery with lower thrombolytic dosages. Currently, there is little guidance on the implementation of USAT in the real-world clinical setting. This study was designed to evaluate our experience with USAT at this single community hospital with a newly initiated Pulmonary Embolism Response Team (PERT). All patients identified by the PERT with an acute PE diagnosed by a computed tomography (CT) scan from January 2021 to January 2023 were included. During the study period, there were 89 PERT activations with 40 patients (1 high-risk and 37 intermediate-risk PE) receiving USAT with alteplase administered at a fixed rate of 1 mg/h per catheter for 6 h. The primary efficacy outcome was the change in Pulmonary Embolism Severity Index (PESI) score within 48 h after USAT. The primary safety outcome was major bleeding within 72 h. The mean age was 57.4 ± 17.4 years and 50% (n = 20) were male, 17.5% (n = 7) had active malignancy, and 20% (n = 8) had a history of prior deep vein thrombosis (DVT) or PE. The mean PESI score decreased from baseline to 48 h post-USAT (84.7 vs 74.9; p = 0.025) and there were no major bleeding events. The overall hospital length of stay was 7.5 ± 9.8 days and ICU length of stay was 2.2 ± 2.8 days. This study outlined our experience at this single community hospital which resulted in an improvement in PESI scores and no major bleeding events observed.

Diagnostic Performance of Perfusion-Only SPECT/CT for Chronic Thromboembolic Pulmonary Hypertension in Comparison With Ventilation-Perfusion Planar, SPECT, and SPECT/CT Imaging.

PURPOSE: The aim of this study was to assess the diagnostic performance of perfusion-only SPECT/CT (Q SPECT/CT) in comparison with that of ventilation/perfusion planar scintigraphy (V/Q planar), perfusion SPECT with ventilation scan (V/Q SPECT), and perfusion SPECT/CT with ventilation scan (V/Q SPECT/CT) in chronic thromboembolic pulmonary hypertension (CTEPH). PATIENTS AND METHODS: Patients with pulmonary hypertension who underwent ventilation-perfusion planar and SPECT/CT were retrospectively recruited. Two nuclear medicine physicians interpreted V/Q planar, V/Q SPECT, V/Q SPECT/CT, and Q SPECT/CT according to the European Association of Nuclear Medicine criteria. The diagnostic accuracy of these modalities for CTEPH was compared using a composite reference standard of pulmonary angiography, imaging test, cardiorespiratory assessment, and follow-up. RESULTS: A total of 192 patients were enrolled, including 85 with CTEPH. The sensitivity of Q SPECT/CT was 98.8%, which similar to that of V/Q planar (97.6%), V/Q SPECT (96.5%), or V/Q SPECT/CT (100.0%). In contrast, Q SPECT/CT exhibited significantly lower specificity (73.8%) compared with V/Q planar (86.9%, P = 0.001), V/Q SPECT (87.9%, P < 0.001), and V/Q SPECT/CT (88.8%, P < 0.001). The significantly lower specificity of Q SPECT/CT, compared with the 3 others, was observed in the subgroup aged ≥50 years ( P < 0.001 for all), but not in those <50 years. CONCLUSIONS: Q SPECT/CT exhibited lower specificity compared with V/Q planar, V/Q SPECT, and V/Q SPECT/CT in diagnosing CTEPH. It might underscore the essential role of a ventilation scan in patients with PH, even with the introduction of SPECT/CT.

A Good Prognosis of Patients with Acute Pancreatitis Combined with Pulmonary Embolism: Early Identification and Intervention.

BACKGROUND: Pulmonary embolism (PE) is a relatively rare vascular complication of acute pancreatitis (AP), and its mortality rate is high. To our knowledge, relevant literature reports still need to be summarized. In this study, we analyzed the clinical characteristics, treatment, and prognosis of five patients with AP complicated by PE and summarized and reviewed the relevant literature. METHODS: Clinical data of patients with AP complicated by PE treated in Taizhou Hospital of Zhejiang Province between January 2017 and September 2022 were retrospectively collected. Combined with the relevant literature, the clinical characteristics, treatment, and prognoses of patients with AP combined with PE were analyzed and summarized. RESULTS: Five patients were eventually enrolled in this study. Among the five patients with AP complicated by PE, all (100%) had symptoms of malaise, primarily chest tightness, shortness of breath, and dyspnea. All patients (100%) had varied degrees of elevated D-dimer levels and a significant decrease in the pressure of partial oxygen (PO2) and pressure of arterial oxygen to fractional inspired oxygen concentration ratio (PaO2/FiO2). Computed tomographic angiography (CTA) or pulmonary ventilation/perfusion imaging revealed a pulmonary artery filling defect in these patients. One patient (20%) had left calf muscular venous thrombosis before the occurrence of PE. Four patients (80%) were treated with lowmolecular- weight heparin (LMWH), and one patient (20%) was treated with rivaroxaban during hospitalization; all continued oral anticoagulant therapy after discharge. All patients (100%) were cured and discharged. No patients showed recurrence of AP or PE. CONCLUSION: PE is a rare but life-threatening complication of AP. However, once diagnosed, early treatment with anticoagulation or radiological interventional procedures is effective, and the prognosis is good. Core Tips: Pulmonary embolism (PE) is a rare but life-threatening complication of acute pancreatitis (AP). Its early diagnosis and timely anticoagulation or radiological intervention can reduce mortality. However, only nine cases have been reported in the English literature thus far, and they are all case reports. Our study is the first systematic analysis of patients with AP combined with PE with a review of the relevant literature. Our patients and those reported in the literature were discharged with good prognoses under treatment such as anticoagulation and vascular intervention. These cases remind clinicians that, in patients with AP, especially those with risk factors for venous thrombosis, it is necessary to monitor the D-dimer level dynamically. Clinicians should pay attention to AP patients' symptoms and related examinations to reduce the chance of a missed diagnosis or misdiagnosis of PE.

Ventilation perfusion functional difference images in lung SPECT: A linear and symmetrical scale as an alternative to the ventilation perfusion ratio.

PURPOSE: Ventilation Perfusion SPECT is important in the diagnostics of e.g. pulmonary embolism and chronic obstructive pulmonary disease. Classical and reverse mismatched defects can be identified by utilizing the ventilation-perfusion ratio. Unfortunately, this ratio is only linear in the ventilation, the scale is not symmetrical regarding classical and reversed mismatches and small perfusion values give rise to artifacts. The ventilation-perfusion (VQ) difference is developed as an alternative. METHODS: For both VQ-ratio and VQ-difference a scaling factor for the perfusion is computed, so that voxels with matched ventilation and perfusion (on average) yield zero signal. The relative VQ-difference is calculated by scaling with the summed VQ-signal in each voxel. The scaled VQ-difference is calculated by scaling with the global maximum of this sum. RESULTS: The relative and scaled differences have a scale from -1 (perfusion only) to + 1 (ventilation only). Image quality of relative VQ-difference and VQ-ratio images is hampered by artifacts from areas with both low perfusion and low ventilation. Ratio and differences have been investigated in ten patients and are shown for three patients (one without defects). Clinical thresholds for the difference images are derived resulting in color maps of relevant (reversed) mismatches with a (reciprocal) ratio larger than two. CONCLUSIONS: The relative ventilation-perfusion difference is a methodological improvement on the ventilation-perfusion ratio, because it has a symmetrical scale and is bound on a closed domain. A better diagnostic value is expected by utilizing the scaled difference, which represents functional difference instead of relative difference.

Prevalence, risk factors, and clinical characteristics of pulmonary embolism in patients with acute exacerbation of COPD in Plateau regions: a prospective cohort study.

BACKGROUND AND OBJECTIVE: To investigate pulmonary thromboembolism (PE) in acute exacerbation of chronic obstructive pulmonary disease (AE-COPD) patients in plateau regions, we performed a prospective cohort study to evaluate the prevalence, risk factors and clinical characteristics of PE in the cohort of hospitalized patients at high altitude. METHODS: We did a prospective study with a total of 636 AE-COPD patients in plateau regions. Demographic and clinical data, laboratory data, including ultrasound scans of the lower extremities and cardiac ultrasound, and computed tomographic pulmonary angiography (CTPA) variables were obtained, and comparisons were made between groups with and without PE. We also conducted logistic regression to explore the risk factors of PE. RESULTS: Of the 636 patients hospitalized with AE-COPD (age 67.0 ± 10.7 years, 445[70.0%] male), 188 patients developed PE (29.6% [95% CI: 26.0%, 33.1%]). Multivariable logistic regression showed that ethnic minorities, D-dimer > 1 mg/L, AST > 40 U/L, chest pain, cardiac insufficiency or respiratory failure, Padua score > 3, and DVT were associated with a higher probability of PE. CONCLUSIONS: The prevalence of PE is high and those with a higher Padua score, the occurrence of deep venous thrombosis, higher neutrophil count, chest pain, cardiac insufficiency or respiratory failure, higher levels of AST, and a higher level of D-dimer had a higher risk of PE. The analysis of AE-COPD may help to provide more accurate screening for PE and improve clinical outcomes of patients with AE-COPD in plateau regions.