The Evolving Landscape of Lung Cancer Surgical Resection: An Update for Radiologists With Focus on Key Chest CT Findings.

Evolution of the multimodality management of early lung cancer, including progress in surgical techniques, has introduced the possibility of resection for lung cancer cases that historically were considered unresectable (e.g., select cases of T4 disease and oligometastatic disease). However, the TNM classification does not uniformly correlate with lung cancer operability and resectability. Radiologic evaluation is therefore critical in identifying patients' suitability to undergo lung cancer resection and in guiding the selection of a surgical approach from among a range of such approaches, including wedge resection, segmentectomy, lobectomy, bilobectomy, and pneumonectomy. The radiologist must understand the available surgical options, along with their advantages and disadvantages, and provide a report that includes critical information on tumor size, location, and extension and anatomic relations that may influence the surgical technique. Preoperative CT findings may also help predict expected postoperative lung function and the associated impact on the postoperative course of the patient. This article reviews the role of chest CT in the preoperative evaluation of lung cancer, focusing on the key CT findings that help direct surgical decision making in the context of an expanding range of patients who may be considered candidates for resection.

Imaging of Immune Checkpoint Inhibitor Immunotherapy for Non-Small Cell Lung Cancer.

The normal immune system identifies and eliminates precancerous and cancerous cells. However, tumors can develop immune resistance mechanisms, one of which involves the exploitation of pathways, termed immune checkpoints, that normally suppress T-cell function. The goal of immune checkpoint inhibitor (ICI) immunotherapy is to boost T-cell-mediated immunity to mount a more effective attack on cancer cells. ICIs have changed the treatment landscape of advanced non-small cell lung cancer (NSCLC), and numerous ICIs have now been approved as first-line treatments for NSCLC by the U.S. Food and Drug Administration. ICIs can cause atypical response patterns such as pseudoprogression, whereby the tumor burden initially increases but then decreases. Therefore, response criteria have been developed specifically for patients receiving immunotherapy. Because ICIs activate the immune system, they can lead to inflammatory side effects, termed immune-related adverse events (irAEs). Usually occurring within weeks to months after the start of therapy, irAEs range from asymptomatic abnormal laboratory results to life-threatening conditions such as encephalitis, pneumonitis, myocarditis, hepatitis, and colitis. It is important to be aware of the imaging appearances of the various irAEs to avoid misinterpreting them as metastatic disease, progressive disease, or infection. The basic principles of ICI therapy; indications for ICI therapy in the setting of NSCLC; response assessment and atypical response patterns of ICI therapy, as compared with conventional chemotherapy; and the spectrum of irAEs seen at imaging are reviewed. An invited commentary by Nishino is available online. ©RSNA, 2022.

Imaging Primer on Chimeric Antigen Receptor T-Cell Therapy for Radiologists.

Chimeric antigen receptor (CAR) T-cell therapy is a recently approved breakthrough treatment that has become a new paradigm in treatment of recurrent or refractory B-cell lymphomas and pediatric or adult acute lymphoid leukemia. CAR T cells are a type of cellular immunotherapy that artificially enhances T cells to boost eradication of malignancy through activation of the native immune system. The CAR construct is a synthetically created functional cell receptor grafted onto previously harvested patient T cells, which bind to preselected tumor-associated antigens and thereby activate host immune signaling cascades to attack tumor cells. Advantages include a single treatment episode of 2-3 weeks and durable disease elimination, with remission rates of over 80%. Responses to therapy are more rapid than with conventional chemotherapy or immunotherapy, with intervening short-interval edema. CAR T-cell administration is associated with therapy-related toxic effects in a large percentage of patients, notably cytokine release syndrome, immune effect cell-associated neurotoxicity syndrome, and infections related to immunosuppression. Knowledge of the expected evolution of therapy response and potential adverse events in CAR T-cell therapy and correlation with the timeline of treatment are important to optimize patient care. Some toxic effects are radiologically evident, and familiarity with their imaging spectrum is key to avoiding misinterpretation. Other clinical toxic effects may be occult at imaging and are diagnosed on the basis of clinical assessment. Future directions for CAR T-cell therapy include new indications and expanded tumor targets, along with novel ways to capture T-cell activation with imaging. An invited commentary by Ramaiya and Smith is available online. Online supplemental material is available for this article. ©RSNA, 2022.

Imaging Evaluation of Tracheobronchial Injuries.

Tracheobronchial injuries are a rare but potentially life-threatening cause of respiratory insufficiency, with high mortality rates. For patients with potentially survivable tracheobronchial injuries, imaging in the acute setting plays a key role in demonstrating the injuries and associated complications. The radiologist can improve outcomes by understanding typical injury patterns according to injury mechanism and the influence that imaging findings may have on treatment decisions. Chest radiography and cervical and thoracic CT are the mainstays of imaging in the acute setting and in follow-up, often as part of a whole-body trauma imaging series. The authors first consider the influence of normal tracheobronchial anatomy with regard to protective features, such as cartilaginous rings. They also discuss inherent points of vulnerability, such as points of relative fixation at the carina. A framework is then provided for understanding the typical distribution and morphology of tracheobronchial injuries according to cause. This includes penetrating, iatrogenic, and blunt force mechanisms, with consideration of potential complications. The authors highlight treatment strategies that require multidisciplinary collaboration, such as ventilation, minimizing injuries, and defining optimal surgical or nonsurgical treatment. ©RSNA, 2020.

Technical and Interpretive Pitfalls in Adrenal Imaging.

The adrenal gland may exhibit a wide variety of pathologic conditions. A number of imaging techniques can be used to characterize these, although it is not always possible to attain a definitive diagnosis radiologically. Incorrect diagnoses may be made if radiologists are not attentive to technical parameters and interpretive factors associated with adrenal gland imaging. Hence, an appreciation of the intricacies of adrenal imaging strategies and characterization is required; this can be aided by understanding the pitfalls of adrenal imaging. Technical pitfalls at CT may relate to the imaging parameters, including region of interest characteristics, tube voltage selection, and the timing of contrast material-enhanced imaging. With MRI, imaging acquisition technique and evaluation of the reference tissues used in chemical shift MRI are important considerations that can directly influence image interpretation. Interpretive errors may occur when evaluating adrenal washout at CT without considering other radiologic features, including the size of adrenal nodules, the presence of fat or calcification, the attenuation of nodules, and atypical imaging features. The characterization of an incidental adrenal lesion as benign or malignant does not end the role of the radiologist; consideration as to whether an adrenal lesion is associated with endocrine dysfunction is required. While imaging may not be optimal for establishing endocrine activity, there are imaging features from which radiologists may infer function. In cases of known endocrine activity, imaging can guide clinical management, including further investigations such as venous sampling. ©RSNA, 2020.

Lung Cancers Associated with Cystic Airspaces: Underrecognized Features of Early Disease.

Early lung cancers associated with cystic airspaces are increasingly being recognized as a cause of delayed diagnoses-owing to data gathered from screening trials and encounters in routine clinical practice as more patients undergo serial imaging. Several morphologic subtypes of cancers associated with cystic airspaces exist and can exhibit variable patterns of progression as the solid elements of the tumor grow. Current understanding of the pathogenesis of these malignancies is limited, and the numbers of cases reported in the literature are small. However, several tumor cell types are represented in these lesions, with adenocarcinoma predominating. The features of cystic airspaces differ among cases and include emphysematous bullae, congenital or fibrotic cysts, subpleural blebs, bronchiectatic airways, and distended distal airspaces. Once identified, these cystic lesions pose management challenges to radiologists in terms of distinguishing them from benign mimics of cancer that are commonly seen in patients who also are at increased risk of lung cancer. Rendering a definitive tissue-based diagnosis can be difficult when the lesions are small, and affected patients tend to be in groups that are at higher risk of requiring biopsy or resection. In addition, the decision to monitor these cases can add to patient anxiety and cause the additional burden of strained departmental resources. The authors have drawn from their experience, emerging evidence from international lung cancer screening trials, and large databases of lung cancer cases from other groups to analyze the prevalence and evolution of lung cancers associated with cystic airspaces and provide guidance for managing these lesions. Although there are insufficient data to support specific management guidelines similar to those for managing small solid and ground-glass lung nodules, these data and guidelines should be the direction for ongoing research on early detection of lung cancer. ©RSNA, 2018.

CT of Normal Developmental and Variant Anatomy of the Pediatric Skull: Distinguishing Trauma from Normality.

The use of computed tomography (CT) in clinical practice has been increasing rapidly, with the number of CT examinations performed in adults and children rising by 10% per year in England. Because the radiology community strives to reduce the radiation dose associated with pediatric examinations, external factors, including guidelines for pediatric head injury, are raising expectations for use of cranial CT in the pediatric population. Thus, radiologists are increasingly likely to encounter pediatric head CT examinations in daily practice. The variable appearance of cranial sutures at different ages can be confusing for inexperienced readers of radiologic images. The evolution of multidetector CT with thin-section acquisition increases the clarity of some of these sutures, which may be misinterpreted as fractures. Familiarity with the normal anatomy of the pediatric skull, how it changes with age, and normal variants can assist in translating the increased resolution of multidetector CT into more accurate detection of fractures and confident determination of normality, thereby reducing prolonged hospitalization of children with normal developmental structures that have been misinterpreted as fractures. More important, the potential morbidity and mortality related to false-negative interpretation of fractures as normal sutures may be avoided. The authors describe the normal anatomy of all standard pediatric sutures, common variants, and sutural mimics, thereby providing an accurate and safe framework for CT evaluation of skull trauma in pediatric patients.

Dual-energy CT for imaging of pulmonary hypertension: challenges and opportunities.

Computed tomography (CT) is routinely used in the evaluation of patients with pulmonary hypertension (PH) to assess vascular anatomy and parenchymal morphology. The introduction of dual-energy CT (DECT) enables additional qualitative and quantitative insights into pulmonary hemodynamics and the extent and variability of parenchymal enhancement. Lung perfusion assessed at pulmonary blood volume imaging correlates well with findings at scintigraphy, and pulmonary blood volume defects seen in pulmonary embolism studies infer occlusive disease with increased risk of right heart dysfunction. Similarly, perfusion inhomogeneities seen in patients with PH closely reflect mosaic lung changes and may be useful for severity assessment and prognostication. The use of DECT may increase detection of peripheral thromboembolic disease, which is of particular prognostic importance in patients with chronic thromboembolic PH with microvascular involvement. Other DECT applications for imaging of PH include low-kilovoltage images with greater inherent iodine conspicuity and iodine-selective color-coded maps of vascular perfusion (both of which can improve visualization of vascular enhancement), virtual nonenhanced imaging (which better depicts vascular calcification), and, potentially, ventricular perfusion maps (to assess myocardial ischemia). In addition, quantitative assessment of central vascular and parenchymal enhancement can be used to evaluate pulmonary hemodynamics in patients with PH. The current status and potential advantages and limitations of DECT for imaging of PH are reviewed, and current evidence is supplemented with data from a tertiary referral center for PH.

Multidetector CT evaluation of airway stents: what the radiologist should know.

Airway stents are increasingly used to treat symptomatic patients with obstructive tracheobronchial diseases who are not amenable to surgical resection or who have poor performance status, precluding them from resection. The most common conditions that are treated with tracheobronchial stents are primary lung cancer and metastatic disease. However, stents have also been used to treat patients with airway stenosis related to a variety of benign conditions, such as tracheobronchomalacia, relapsing polychondritis, postintubation tracheal stenosis, postoperative anastomotic stenosis, and granulomatous diseases. Additionally, airway stents can be used as a barrier method in the management of esophagorespiratory fistulas. Many types of stents are available from different manufacturers. Principally, they are classified as silicone; covered and uncovered metal; or hybrid, which are made of silicone and reinforced by metal rings. The advantages and disadvantages of each type of airway stent are carefully considered when choosing the most appropriate stent for each patient. Multidetector computed tomography plays an important role in determining the cause and assessing the location and extent of airway obstruction. Moreover, it is very accurate in its depiction of complications after airway stent placement.

COPD-related bronchiectasis; independent impact on disease course and outcomes.

BACKGROUND: COPD and radiographic bronchiectasis frequently coexist but the effect of this on the clinical course of COPD is not fully understood. We determined the impact of bronchiectasis on clinical outcomes in COPD patients, independent of coexisting emphysema and bronchial wall thickening (BWT). METHODS: COPD patients admitted with first exacerbation 1998-2008 were identified retrospectively using ICD10 codes J44.0,1,8,9. Patients with suitable CT scans were graded for severity of bronchiectasis, emphysema and BWT on a 5 point scale (0-absent, 1-minor, 2-mild, 3-moderate, 4-severe). RESULTS: 406 patients (71 ± 11 years, 56% male, FEV1 52 ± 23% predicted) were included; 278 (69%) patients had bronchiectasis: minor, 112 (40%); mild, 81 (29%); moderate, 62 (22%); severe 23 (8%). Bronchiectasis severity correlated with severity of BWT (p < 0.001) but not emphysema (p = 0.090). Bronchiectasis independently determined sputum isolation of Pseudomonas aeruginosa (Odds ratio (OR) 1.39 (95% CI 1.07 to 1.80), p = 0.013) and atypical mycobacteria (OR 2.44 (95% CI 1.04 to 5.69), p = 0.040), annual respiratory admissions (p = 0.044) and inpatient days (p < 0.001), but did not predict survival (p = 0.256). CONCLUSIONS: Radiographic bronchiectasis in COPD patients is associated with increased respiratory infection and hospitalisation, independent of coexisting emphysema and BWT. COPD-related bronchiectasis is therefore an important diagnosis with potential implications for treatment.

Drug-induced Lung Disease in the Oncology Patient: From Cytotoxic Agents to Immunotherapy.

Drug-induced lung disease is commonly encountered, especially in the oncology setting. Diagnosis is challenging because clinical and radiologic findings are nonspecific, often overlapping with other lung pathologies in these patients due to underlying neoplasia, infection, or other treatment effects such as radiotherapy. Furthermore, oncology patients often receive multiple antineoplastic agents concurrently, and virtually every agent has an association with lung injury. In this article, we will review a variety of antineoplastic agents that are associated with drug-induced injury and discuss incidence, their typical timing of onset, and imaging features.

Backlogs in formal interpretation of radiology examinations: a pilot global survey.

OBJECTIVE: Anecdotal reports from imaging facilities globally suggest growing radiology interpretation reporting delays. This pilot study's primary aim was to estimate the backlog of formal interpretation of imaging examinations. METHODS: An online survey was distributed to radiologists globally to gather practice-specific characteristics, imaging volumes, and reporting for 3 types of examinations (brain/head CT scans, chest CT scans, and chest radiographs) at 4 time points: 7, 30, 90 days, and 6 months. RESULTS: We received responses from 49 radiologists in 16 countries on six continents. Unreported examinations (backlog) were present in thirty of 44 (68%) facilities. Backlogs for brain/head CT, chest CT, and chest radiographs were present in, respectively, 48%, 50%, and 59% of facilities at 7 days and 20%, 23%, and 32% of facilities at 6 months. When present, the mean proportion of backlog (range) at 7 days was 17% (1 to 96) for brain/head CT, 18% (3 to 82) for chest CT, and 22% (1 to 99) for chest radiographs. CONCLUSIONS: Our findings from this pilot study show a widespread global backlog in reporting common imaging examinations, and further research is needed on the issue and contributing factors.

18F-FDG PET/CT anatomic and metabolic guidance in CT-guided lung biopsies.

PURPOSE: To evaluate the role of Fluorine-18 fluorodeoxyglucose (18F-FDG) PET/CT as a metabolic guide in increasing the accuracy, diagnostic yield and safety of CT-guided percutaneous needle lung biopsy (PNB). METHODS AND MATERIALS: Retrospective analysis of 340 consecutive patients with suspicious lung nodules, masses or extensive disease that underwent lung biopsy over a 3-year period. Patients were divided into three groups; those that had PET/CT prior to the biopsy, those that had PET-CT following the biopsy and those who did not undergo PET-CT. Correlation was made with the histopathological result. RESULTS: 353 PNBs were performed (median lesion size 30 mm, 7-120 mm) with overall diagnostic rate of 83.9 % (95.8 % malignant). Biopsy success rate was 88.8 % with PET-CT pre-PNB, versus 78.9 % of 175 PNB without PET-CT upfront (p < 0.01 Fisher exact test). Correct targeting to PET-CT-maximum activity area (MAA) was present in 87.1 %. Biopsy success rate was 88.8 % for PNBs targeting the PET-CT-MAA region and only 52.8 % for PNBs not targeting the PET-CT-MAA (p < 0.0001). PET-CT pre-PNB had higher rates of PET-CT-MAA targeting compared to PET-CT post PNB (91.0 % v 80.0 %, p = 0.01). The availability of PET-CT before the PNB lead to significantly increased biopsy success rates in patients with a mass (OR:7.01p = 0.004), compared to a nodule (p = 0.498) or multiple nodules (p = 0.163). Patients with a PET-CT pre-PNB underwent fewer PNB passes (mean 2.6 v 3.1, p < 0.0001 Mann Whitney U). Serious complications were less common in PET-CT pre-PNB group (4.5 % v 10.9 %, p < 0.05). Pre-PNB PET-CT performance improvement applied to all 3 radiologists and was greatest for masses and infiltrative abnormalities. CONCLUSION: Metabolic information provided by 18F-FDG PET/CT and PNB localisation to the PET-CT maximum activity region is associated with higher diagnostic biopsy rates especially in masses and appears to account for improved performance, less needle passes and complications when available pre-biopsy.

Benefit of computer-aided detection analysis for the detection of subsolid and solid lung nodules on thin- and thick-section CT.

OBJECTIVE: The objective of our study was to evaluate the impact of computer-aided detection (CAD) on the identification of subsolid and solid lung nodules on thin- and thick-section CT. MATERIALS AND METHODS: For 46 chest CT examinations with ground-glass opacity (GGO) nodules, CAD marks computed using thin data were evaluated in two phases. First, four chest radiologists reviewed thin sections (reader(thin)) for nodules and subsequently CAD marks (reader(thin) + CAD(thin)). After 4 months, the same cases were reviewed on thick sections (reader(thick)) and subsequently with CAD marks (reader(thick) + CAD(thick)). Sensitivities were evaluated. Additionally, reader(thick) sensitivity with assessment of CAD marks on thin sections was estimated (reader(thick) + CAD(thin)). RESULTS: For 155 nodules (mean, 5.5 mm; range, 4.0-27.5 mm)-74 solid nodules, 22 part-solid (part-solid nodules), and 59 GGO nodules-CAD stand-alone sensitivity was 80%, 95%, and 71%, respectively, with three false-positives on average (0-12) per CT study. Reader(thin) + CAD(thin) sensitivities were higher than reader(thin) for solid nodules (82% vs 57%, p < 0.001), part-solid nodules (97% vs 81%, p = 0.0027), and GGO nodules (82% vs 69%, p < 0.001) for all readers (p < 0.001). Respective sensitivities for reader(thick), reader(thick) + CAD(thick), reader(thick) + CAD(thin) were 40%, 58% (p < 0.001), and 77% (p < 0.001) for solid nodules; 72%, 73% (p = 0.322), and 94% (p < 0.001) for part-solid nodules; and 53%, 58% (p = 0.008), and 79% (p < 0.001) for GGO nodules. For reader(thin), false-positives increased from 0.64 per case to 0.90 with CAD(thin) (p < 0.001) but not for reader(thick); false-positive rates were 1.17, 1.19, and 1.26 per case for reader(thick), reader(thick) + CAD(thick), and reader(thick) + CAD(thin), respectively. CONCLUSION: Detection of GGO nodules and solid nodules is significantly improved with CAD. When interpretation is performed on thick sections, the benefit is greater when CAD marks are reviewed on thin rather than thick sections.

Idiopathic inflammatory myositis-associated interstitial lung disease: ethnicity differences and lung function trends in a British cohort.

OBJECTIVE: Interstitial lung disease (ILD) is an important feature of idiopathic inflammatory myositis (IIM). Factors associated with its development and progression remain incompletely understood. The authors report ethnicity differences and lung function trends that characterize the predilection for and natural history of ILD in a group of British patients with IIM. METHODS: A 10-year retrospective analysis of patients with IIM at two hospitals was conducted. Demographic, clinico-radiological and laboratory features of cases with and without ILD were compared. Serial pulmonary function tests, including measurements of forced vital capacity, volume and diffusing capacity for carbon monoxide, were used to identify longitudinal patterns of lung disease. RESULTS: A total of 107 patients with IIM were identified. ILD was present in 37.4%, with non-specific interstitial pneumonia being the most common radiological pattern (75%). ILD was more common in IIM patients of Black ethnicity (OR 3.42), and in cases where ANA (OR 3.06) and anti-histidyl-tRNA synthetase (OR 3.2) antibodies were detected. In the ILD cohort, 50% deteriorated, defined as a drop in diffusing capacity of the lung for carbon monoxide by <15% or forced vital capacity <10% during the study period, occurring in all within a year of onset of ILD and significantly more frequently in those with a synchronous onset of IIM and ILD. Black ethnicity was not associated with poor lung function outcome. CONCLUSION: In IIM, the risk of developing ILD is significantly higher in patients of Black ethnicity. Progressive lung damage occurs in an appreciable subgroup of patients with IIM-ILD, heralded by functional lung decline at 1 year despite systemic immunomodulatory treatment.

Dual-energy CT: vascular applications.

OBJECTIVE: Dual-energy CT permits a variety of image reconstructions for the depiction and characterization of vascular disease. Techniques include visualization of low- and high-peak-kilovoltage spectra image datasets and also material-specific reconstructions combining both low- and high-peak-kilovoltage data. CONCLUSION: This article focuses on four main vascular areas: the aorta, the major visceral, lower limb, and cervical arteries. For each territory, the current status, potential advantages, and limitations of these techniques are described.

Chest radiography in the ICU: Part 1, Evaluation of airway, enteric, and pleural tubes.

OBJECTIVE: In this pictorial essay, we discuss and illustrate normal and aberrant positioning of nonvascular support and monitoring devices frequently used in critically ill patients, including endotracheal and tracheostomy tubes, chest tubes, and nasogastric and nasoenteric tubes, as well as their inherent complications. CONCLUSION: The radiographic evaluation of the support and monitoring devices used in patients in the ICU is important because the potentially serious complications arising from their introduction and use are often not clinically apparent. Familiarity with normal and abnormal radiographic findings is critical for the detection of these complications.

Chest radiography in the ICU: Part 2, Evaluation of cardiovascular lines and other devices.

OBJECTIVE: In this pictorial essay, we discuss and illustrate normal and aberrant positioning of the cardiovascular support and monitoring devices frequently used in critically ill patients, including central venous catheters, pulmonary artery catheters, left atrial catheters, transvenous pacemakers, automatic implantable cardioverter defibrillators, intraaortic counterpulsation balloon pump, and ventricular assist devices, as well as their inherent complications. CONCLUSION: The radiographic evaluation of the support and monitoring devices used in patients in the ICU is important, because the potentially serious complications arising from their introduction and use are often not clinically apparent. Familiarity with normal and abnormal radiographic findings is critical for the detection of these complications.

Multidetector CT and postprocessing in planning and assisting in minimally invasive bronchoscopic airway interventions.

A widening spectrum of increasingly advanced bronchoscopic techniques is available for the diagnosis and treatment of various bronchopulmonary diseases. The evolution of computed tomography (CT)-multidetector CT in particular-has paralleled these advances. The resulting development of two-dimensional and three-dimensional (3D) postprocessing techniques has complemented axial CT interpretation in providing more anatomically familiar information to the pulmonologist. Two-dimensional techniques such as multiplanar recontructions and 3D techniques such as virtual bronchoscopy can provide accurate guidance for increasing yield in transbronchial needle aspiration and transbronchial biopsy of mediastinal and hilar lymph nodes. Sampling of lesions located deeper within the lung periphery via bronchoscopic pathways determined at virtual bronchoscopy are also increasingly feasible. CT fluoroscopy for real-time image-guided sampling is now widely available; electromagnetic navigation guidance is being used in select centers but is currently more costly. Minimally invasive bronchoscopic techniques for restoring airway patency in obstruction caused by both benign and malignant conditions include mechanical strategies such as airway stent insertion and ablative techniques such as electrocauterization and cryotherapy. Multidetector CT postprocessing techniques provide valuable information for planning and surveillance of these treatment methods. In particular, they optimize the evaluation of dynamic obstructive conditions such as tracheobronchomalacia, especially with the greater craniocaudal coverage now provided by wide-area detectors. Multidetector CT also provides planning information for bronchoscopic treatment of bronchopleural fistulas and bronchoscopic lung volume reduction for carefully selected patients with refractory emphysema.

Dual-energy CT in pulmonary vascular disease.

Dual-energy CT (DECT) imaging is a technique that extends the capabilities of CT beyond that of established densitometric evaluations. CT pulmonary angiography (CTPA) performed with dual-energy technique benefits from both the availability of low kVp CT data and also the concurrent ability to quantify iodine enhancement in the lung parenchyma. Parenchymal enhancement, presented as pulmonary perfused blood volume maps, may be considered as a surrogate of pulmonary perfusion. These distinct capabilities have led to new opportunities in the evaluation of pulmonary vascular diseases. Dual-energy CTPA offers the potential for improvements in pulmonary emboli detection, diagnostic confidence, and most notably severity stratification. Furthermore, the appreciated insights of pulmonary vascular physiology conferred by DECT have resulted in increased use for the assessment of pulmonary hypertension, with particular utility in the subset of patients with chronic thromboembolic pulmonary hypertension. With the increasing availability of dual energy-capable CT systems, dual energy CTPA is becoming a standard-of-care protocol for CTPA acquisition in acute PE. Furthermore, qualitative and quantitative pulmonary vascular DECT data heralds promise for the technique as a "one-stop shop" for diagnosis and surveillance assessment in patients with pulmonary hypertension. This review explores the current application, clinical value, and limitations of DECT imaging in acute and chronic pulmonary vascular conditions. It should be noted that certain manufacturers and investigators prefer alternative terms, such as spectral or multi-energy CT imaging. In this review, the term dual energy is utilised, although readers can consider these terms synonymous for purposes of the principles explained.