Chest CT Lung Abnormalities 1 Year after COVID-19: A Systematic Review and Meta-Analysis.

Background Radiological lung sequelae may explain the persistence of respiratory complaints in post-COVID-19 condition (long-COVID). Purpose To perform a systematic review and meta-analysis of the prevalence and type of COVID-19 residual lung abnormalities at 1-year chest CT. Materials and Methods A literature search of PubMed, Web of Science, Embase, and Medline databases was performed from January 2020 to January 2023. Full-text reports of CT lung sequelae in adults (≥18 years) with confirmed COVID-19 at 1-year follow-up were included. The prevalence of any residual lung abnormality and type (fibrotic or not) was analyzed according to the Fleischner Glossary. The meta-analysis included studies with chest CT data assessable in no less than 80% of individuals. A random-effects model was used to estimate pooled prevalence. Multiple sub-group (country, journal category, methodological quality, study setting, outcomes) and meta-regression analyses were performed to identify potential sources of heterogeneity. I2 statistics estimated low (25%), moderate (26-50%) and high (>50%) heterogeneity. 95% Prediction Intervals (95% PIs) were computed to describe the expected estimates range. Results Of 22 709 records, 21 studies were reviewed (20 prospective, 9 from China, and 7 in radiology journals). The meta-analysis included 14 studies with chest CT data in 1854 of 2043 individuals (M/F: 1109/934). Estimates of lung sequelae were highly heterogeneous (7.1-96.7%), with a pooled frequency of 43.5% (I2=94%; 95% PI: 5.9%, 90.4%). This also applied to single non-fibrotic changes, including ground glass opacity, consolidations, nodules/masses, parenchymal bands, and reticulations. The prevalence range of fibrotic traction bronchiectasis/bronchiolectasis was 1.6-25.7% (I2=93%; 95% PI: 0.0%, 98.6%;); honeycombing was unremarkable (0-1.1%; I2=58%; 95% PI: 0%, 60%). Lung sequelae were unrelated to any characteristics of interest. Conclusion The prevalence of COVID-19 lung sequelae at 1-year chest CT is highly heterogeneous among studies. Heterogeneity determinants remain unknown suggesting caution in data interpretation with no convincing evidence. PROSPERO (CRD42022341258) Keywords: COVID-19 pneumonia, pulmonary fibrosis, chest CT, long-COVID, systematic review, metaanalysis See also the editorial by Parraga and Svenningsen in this issue.

Chest CT-based Assessment of 1-year Outcomes after Moderate COVID-19 Pneumonia.

BACKGROUND: COVID-19 pneumonia may lead to pulmonary fibrosis in the long term. Chest CT is useful to evaluate changes in the lung parenchyma over time. PURPOSE: To illustrate the temporal change of lung abnormalities on chest CT scans associated with COVID-19 pneumonia over 1 year. MATERIALS AND METHODS: In this prospective study, patients previously hospitalized due to COVID-19 pneumonia who visited the radiology department of a tertiary care center for imaging follow-up were consecutively enrolled between March 2020 and July 2021. Exclusion criteria were acute respiratory distress syndrome, requirement of intubation and/or mechanical ventilation, pulmonary embolism, and any interstitial lung disease. High-resolution volumetric noncontrast chest CT scans were acquired at 3, 6, and 12 months from the first diagnosis and were compared with baseline CT scans. The imaging features analyzed were ground-glass opacity (GGO), consolidation, pleuroparenchymal band, linear atelectasis, bronchiectasis and/or bronchiolectasis, reticulation, traction bronchiectasis and/or bronchiolectasis, and honeycombing. The prevalence distribution of lung abnormalities was recorded at all time points. RESULTS: Eighty-four participants (56 men; mean age, 61 years ± 11 [SD]) were studied. GGOs and consolidations represented the main baseline lung abnormalities, accounting for a median severity score of 9 (IQR, 7-12.7; maximum possible score, 20), which indicates moderate lung involvement. The baseline prevalence of GGOs decreased from 100% to 2% of participants at 1 year, and that of consolidations decreased from 71% to 0% at 6 months. Fibrotic-like abnormalities (pleuroparenchymal bands, linear atelectasis, bronchiectasis and/or bronchiolectasis) were detected at 3 months (50% of participants), 6 months (42% of participants), and 1 year (5% of participants). Among these, pleuroparenchymal bands were the most represented finding. Fibrotic changes (reticulation and traction bronchiectasis and/or bronchiolectasis) were detected at 3-6 months (2%) and remained stable at 1 year, with no evidence of honeycombing. At 1 year, lung abnormalities due to COVID-19 pneumonia were completely resolved in 78 of 84 (93%) participants. CONCLUSION: Residual lung abnormalities in individuals hospitalized with moderate COVID-19 pneumonia were infrequent, with no evidence of fibrosis at 1-year chest CT. © RSNA, 2022.

Echocardiographic probability of pulmonary hypertension: a validation study.

BACKGROUND: According to current guidelines, the diagnosis of pulmonary hypertension (PH) relies on echocardiographic probability followed by right heart catheterisation (RHC). How echocardiography predicts PH recently redefined by mean pulmonary arterial pressure (mPAP) >20 mmHg instead of ≥25 mmHg and pulmonary vascular disease defined by pulmonary vascular resistance (PVR) ≥3 or >2 WU has not been established. METHODS: A total of 278 patients referred for PH underwent comprehensive echocardiography followed by RHC. 15 patients (5.4%) were excluded because of insufficient quality echocardiography. RESULTS: With PH defined by mPAP >20 mmHg, 23 patients had no PH, 146 had pre-capillary PH and 94 had post-capillary PH. At univariate analysis, maximum tricuspid regurgitation velocity (TRV) 2.9-3.4 m·s-1, left ventricle (LV) eccentricity index >1.1, right ventricle outflow tract acceleration time (RVOT-AT) <105 ms or notching, RV/LV basal diameter >1 and pulmonary artery diameter predicted PH, whereas inferior vena cava diameter and right atrial area did not. At multivariable analysis, only TRV ≥2.9 m·s-1 independently predicted PH. Additional independent prediction of PVR ≥3 WU was offered by LV eccentricity index >1.1, and RVOT-AT <105 ms and/or notching, but with no improvement of optimal combination of specificity and sensitivity or positive prediction. CONCLUSIONS: Echocardiography as recommended in current guidelines can be used to assess the probability of redefined PH in a referral centre. However, the added value of indirect signs is modest and sufficient quality echocardiographic signals may not be recovered in some patients.

Intradiscal ozone therapy: fluoroscopic guidance reduces operative time in comparison with CT guidance in patients with lumbar disc herniation.

PURPOSE: To compare clinical success and operative time for percutaneous intradiscal ozone therapy in patients with lumbar disc herniation using fluoroscopic guidance versus computed tomography (CT). MATERIALS AND METHODS: During the year 2019, 68 percutaneous single-level intradiscal ozone therapies were performed on patients complaining of low back pain and/or sciatica due to lumbar disc herniation, using fluoroscopic or conventional CT guidance, respectively, in 35 and 32 herniated lumbar discs, with at least 1-month follow-up. Oswestry Disability Index (ODI) was used to assess clinical outcome. Total room utilization time and procedure operative time were recorded for both fluoroscopy and CT guidance. RESULTS: Fluoroscopy and CT groups were similar in terms of patient age (p value 0.45) and pre-procedure ODI (p value 0.64). Clinical success was obtained in 87.50% (28/32) patients in fluoroscopic group and 83.33% (30/36) in CT group. Mean total room utilization time was significantly longer for CT guidance (31.38 vs. 50.67 min, p < 0.0001), as well as the procedure operative time (15.94 vs. 27.61 min, p < 0.0001). CONCLUSIONS: Compared to conventional CT guidance, fluoroscopic guidance for percutaneous intradiscal ozone therapy in patients with lumbar disc herniation shows similar clinical success rates at 1-month follow-up, with decreased room utilization time and procedure operative time that implies less time consumption for medical and paramedical operative team.

Lesson by SARS-CoV-2 disease (COVID-19): whole-body CT angiography detection of "relevant" and "other/incidental" systemic vascular findings.

OBJECTIVES: Increasing evidence suggests that SARS-CoV-2 infection may lead to severe and multi-site vascular involvement. Our study aimed at assessing the frequency of vascular and extravascular events' distribution in a retrospective cohort of 42 COVID-19 patients. METHODS: Patients were evaluated by whole-body CT angiography between March 16 and April 30, 2020. Twenty-three out of the 42 patients evaluated were admitted to the intensive care unit (ICU). Vascular and extravascular findings were categorized into "relevant" or "other/incidental," first referring to the need for immediate patient care and management. Student T-test, Mann-Whitney U test, or Fisher exact test was used to compare study groups, where appropriate. RESULTS: Relevant vascular events were recorded in 71.4% of cases (n = 30). Pulmonary embolism was the most frequent in both ICU and non-ICU cases (56.5% vs. 10.5%, p = 0.002). Ischemic infarctions at several sites such as the gut, spleen, liver, brain, and kidney were detected (n = 20), with multi-site involvement in some cases. Systemic venous thrombosis occurred in 30.9% of cases compared to 7.1% of systemic arterial events, the first being significantly higher in ICU patients (p = 0.002). Among incidental findings, small-sized splanchnic arterial aneurysms were reported in 21.4% of the study population, with no significant differences in ICU and non-ICU patients. CONCLUSIONS: Vascular involvement is not negligible in COVID-19 and should be carefully investigated as it may significantly affect disease behavior and prognosis. KEY POINTS: • Relevant vascular events were recorded in 71.4% of the study population, with pulmonary embolism being the most frequent event in ICU and non-ICU cases. • Apart from the lung, other organs such as the gut, spleen, liver, brain, and kidneys were involved with episodes of ischemic infarction. Systemic venous and arterial thrombosis occurred in 30.9% and 7.1% of cases, respectively, with venous events being significantly higher in ICU patients (p = 0.002). • Among incidental findings, small-sized splanchnic arterial aneurysms were reported in 21.4% of the whole population.

Hemopericardium in the acute clinical setting: Are we ready for a tailored management approach on the basis of MDCT findings?

The clinical spectrum of pericardial effusions varies from innocuous serous fluid to life-threatening hemopericardium. A misdiagnosis may be made by similar clinical presentation of acute chest pain/hypotension. Echocardiography is the first-line test for diagnosis of pericardial effusion and its etiology, but sometimes there are different drawbacks to the correct cardiovascular ultrasound diagnosis. Radiologists are reporting an increasing amount of thoracic Multidetector CT examinations at the emergency department. Multidetector CT has now become an established and complementary method for cardiac imaging, and diseases of the pericardium can now be quickly identified with increasing certainty. The aim of this review is to discuss the hemopericardium key Multidetector CT features in acute clinical setting which indicate the need to proceed with predominantly medical or surgical treatment, however, being able to identify forms of bleeding pericardial effusion for which only "a watch and wait strategy" and/or deferred treatment is indicated. In the emergency care setting, radiologists must be aware of different findings of hemopericardium in order to address a tailored and timely management approach.

Comparative analysis of density histograms and visual scores in incremental and volumetric high-resolution computed tomography of the chest in idiopathic pulmonary fibrosis patients.

BACKGROUND: Volumetric high-resolution computed tomography (HRCT) of the chest has recently replaced incremental CT in the diagnostic workup of idiopathic pulmonary fibrosis (IPF). Concomitantly, visual and quantitative scores have been proposed for disease extent assessment to ameliorate disease management. PURPOSE: To compare the performance of density histograms (mean lung attenuation, skewness, and kurtosis) and visual scores, along with lung function correlations, in IPF patients submitted to incremental or volumetric thorax HRCT. MATERIAL AND METHODS: Clinical data and CT scans of 89 newly diagnosed and therapy-naive IPF patients were retrospectively evaluated. RESULTS: Forty-six incremental and 43 volumetric CT scans were reviewed. No differences of density histograms and visual scores estimates were found by comparing two HRCT techniques, with an optimal inter-operator agreement (concordance correlation coefficient >0.90 in all instances). Single-breath diffusing lung capacity for carbon monoxide (DLCOsb) was inversely related with the Best score (r = -00.416; p = 0.014), the Kazerooni fibrosis extent (r = -0.481; p = 0.004) and the mean lung attenuation (r = -0.382; p = 0.026), while a positive correlation was observed with skewness (r = 0.583; p = 0.001) and kurtosis (r = 0.543; p = 0.001) in the incremental HRCT sub-group. Similarly, in the volumetric CT sub-cohort, DLCOsb was significantly associated with skewness (r = 0.581; p = 0.007) and kurtosis (r = 0.549; p = 0.018). Correlations with visual scores were not confirmed. Forced vital capacity significantly related to all density indices independently on HRCT technique. CONCLUSIONS: Density histograms and visual scores similarly perform in incremental and volumetric HRCT. Density quantification displays an optimal reproducibility and proves to be superior to visual scoring as more strongly correlated with lung function.

E-cigarette, or vaping, product use Associated Lung Injury (EVALI): new scenarios for physicians and radiologists.

A 59-year-old female ex-smoker with 40 pack year smoking history and a 5-year current e-cigarette (EC) use history, presented with progressive dyspnea on exertion and daily cough for 2 months. A CT scan showed a consolidation area with air bronchogram in the middle lobe and non-calcific bilateral nodules, which could be attributed to community-acquired pneumonia. The patient was treated with empiric antibiotics and systemic steroids for 10 days. Infectious, neoplastic and autoimmune pathologies were excluded, whereas a broncho-alveolar lavage revealed an accumulation of lipids in the cytoplasm of the alveolar macrophages. Despite the recommendation of vaping cessation, the patient continued to use EC. A new CT exam, carried out after 18 months, showed reversed halo sign (RHS), patchy ground-glass opacity (GGO), pleuro-parenchymal bands, and indeed perilobular pattern, suggestive of organizing pneumonia (OP). The final diagnosis was E-cigarette, or vaping, product use Associated Lung Injury (EVALI)- related OP.

Low Sensitivity of Admission Lung US Compared to Chest CT for Diagnosis of Lung Involvement in a Cohort of 82 Patients with COVID-19 Pneumonia.

Background and Objectives: The potential role of lung ultrasound (LUS) in characterizing lung involvement in Coronavirus disease 2019 (COVID-19) is still debated. The aim of the study was to estimate sensitivity of admission LUS for the detection of SARS-CoV-2 lung involvement using Chest-CT (Computed Tomography) as reference standard in order to assess LUS usefulness in ruling out COVID-19 pneumonia in the Emergency Department (ED). Methods: Eighty-two patients with confirmed COVID-19 and signs of lung involvement on Chest-CT were consecutively admitted to our hospital and recruited in the study. Chest-CT and LUS examination were concurrently performed within the first 6-12h from admission. Sensitivity of LUS was calculated using CT findings as a reference standard. Results: Global LUS sensitivity in detecting COVID-19 pulmonary lesions was 52%. LUS sensitivity ranged from 8% in case of focal and sporadic ground-glass opacities (mild disease), to 52% for a crazy-paving pattern (moderate disease) and up to 100% in case of extensive subpleural consolidations (severe disease), although LUS was not always able to detect all the consolidations assessed at Chest-CT. LUS sensitivity was higher in detecting a typical Chest-CT pattern (60%) and abnormalities showing a middle-lower zone predominance (79%). Conclusions: As admission LUS may result falsely negative in most cases, it should not be considered as a reliable imaging tool in ruling out COVID-19 pneumonia in patients presenting in ED. It may at least represent an expanded clinical evaluation that needs integration with other diagnostic tests (e.g., nasopharyngeal swab, Chest-CT).

The lung ultrasound: facts or artifacts? In the era of COVID-19 outbreak.

Ultrasound is the most disruptive innovation in intensive care life, above all in this time, with a high diagnostic value when applied appropriately. In recent years, point-of-care lung ultrasound has gained significant popularity as a diagnostic tool in the acutely dyspnoeic patients. In the era of Sars-CoV-2 outbreak, lung ultrasound seems to be strongly adapting to the follow-up for lung involvement of patients with ascertaining infections, till to be used, in our opinion emblematically, as a screening test in suspected patients at the emergency triage or at home medical visit. In this brief review, we discuss the lung ultrasound dichotomy, certainties and uncertainties, describing its potential role in validated clinical contexts, as a clinical-dependent exam, its limits and pitfalls in a generic and off-label clinical context, as a virtual anatomical-dependent exam, and its effects on the clinical management of patients with COVID-19.

First MDCT evidence of ruptured aberrant left subclavian artery aneurysm in right aortic arch, Kommerell's diverticulum and extrapleural hematoma treated by emergency thoracic endovascular aortic repair.

Spontaneous ruptured aneurysm involving an aberrant subclavian artery with a right-sided aortic arch and Kommerell's diverticulumis a rare life-threatening condition that can be treated successfully if promptly identified. Multidetector Computed Tomography angiography is the first line imaging modality of thoracic vascular anomalies diagnosis. We report the case of a 74-year-old man suffering from this emergency ondition with mediastinal hematoma mostly extending to the left-side extrapleural cavity. The patient underwent successful emergency thoracic endovascular aortic repair and an Amplatzer vascular plug was placed into the first segment of the ALSA. Post-procedural imaging showed complete exclusion of the aneurysm. Emergency endovascular repair can be effective in such cases.

Safety maximization of percutaneous transthoracic needle biopsy with ultrasound guide in subpleural lesions in the evaluation of pulmonary consolidation.

The study by Kiranantawat et al. "Clinical role, safety and diagnostic accuracy of percutaneous transthoracic needle biopsy in the evaluation of pulmonary consolidation" highlights how "pulmonary consolidation can be safely evaluated with CT-guided percutaneous needle biopsy". Even if we agree about the role of CT guidance, we would like to point out how Thoracic Ultrasound could be better than CT for biopsy of subpleural lesions that could easily be detected and reached with this "real-time" and quicker technique.

Non-small cell lung cancer presenting as "psoas muscle syndrome".

Lung cancer is the leading cause of cancer-related death worldwide and majority of patients are diagnosed in advanced/metastatic disease stage. Sites of distant metastases mainly include contralateral lung, lymph nodes, brain, bones, adrenal glands and liver; skeletal muscles metastases (SMMs) are less common. Psoas muscle and diaphragm metastases are mainly found during autopsy, as their involvement commonly is asymptomatic. We report a case of a 60-year-old female, suffering from non-small cell lung cancer (NSCLC), with refractory lower back pain, as expression of malignant psoas syndrome (MPS). MPS is a rare and difficult-to-treat cancer-pain syndrome, unresponsive to majority of analgesic therapy, related to psoas muscle metastasis; it is usually caused by different tumors such as uterus, ovary, bladder, prostate, colon-rectum, lymphoma, melanoma and sarcoma and represents an uncommon finding in NSCLC patients.

Acquired peripheral pulmonary artery aneurysms: morphological spectrum of disease and multidetector computed tomography angiography findings-cases series and literature review.

BACKGROUND: Acquired peripheral or intraparenchymal pulmonary artery aneurysms (PPAA) are rare entities but are important to recognize because of the associated morbidity. Hemoptysis is their principal complication and is a potentially fatal condition. PURPOSE: To illustrate the causes, multidetector CT angiography (MDCTA) findings and differential diagnosis of acquired PPAA. MATERIALS AND METHODS: The institutional review boards approved this study. We conducted a retrospective review of the demographic data and the results of clinical and laboratory examinations, and imaging studies of patients managed between January 2012 and January 2017 in two institutions. RESULTS: A total of 19 patients had acquired PPAA that were detected at MDCTA, 9 patients with normal pulmonary artery pressures and 10 with pulmonary hypertension. Nine patients developed PPAA-related acute symptoms. MDCTA features of PPAA include: a lobulated vascular mass, an indistinct irregular arterial wall, aneurysmal thrombosis or wall calcification, findings of impending rupture including perianeurysmal edema, gas or a soft tissue mass. CONCLUSION: PPAA are rare. In our series, endocarditis and pulmonary hypertension are the PPAA leading causes. The treatment modality preferred is embolization, especially as surgery poses a very high risk for patients with severe pulmonary hypertension. Further clarification of the natural history of these rare arterial aneurysms is needed.

Pulmonary veins stenosis relief after an inappropriate radiofrequency catheter ablation of atrial fibrillation in a young non-competitive athlete.

One of the major complications of radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) is pulmonary vein stenosis (PVS). The natural history of PVS, especially when it involves more than one vein, leads to severe and irreversible pulmonary hypertension with end-stage right heart failure that can require, in extreme cases, even heart-lung transplantation. We report the case of a young patient who underwent RFCA for a single lasting episode of AF and developed PVS years later. He was treated with ballon venoplasty followed by stent implantation in left pulmonary vein because of PVS relief. This reported case emphasizes the need of an adequate indication for RFCA for AF, considering the benefit-risk ratio especially in young patients with normal cardiac function.

Contrast-enhanced ultrasound does not discriminate between community acquired pneumonia and lung cancer.

We investigated if contrast-enhanced ultrasound (CEUS) may differentiate community acquired pneumonia (CAP) from lung cancer (LC). Among 1374 patients admitted in a 5-year period for lung opacities, 728 (329 CAP and 399 LC) were investigated by CEUS, comparing the time of appearance, disappearance, duration and pattern of distribution of contrast enhancement (CE). The patients with CAP and LC did not differ in terms of age, time of CE appearance, disappearance and duration or CE distribution. Our data show that the timing and pattern of CE detected by chest CEUS does not distinguish between CAP and LC and overly optimistic beliefs on this matter should be abandoned.

Assessment of thoracic ultrasound in complementary diagnosis and in follow up of community-acquired pneumonia (cap).

BACKGROUND: Chest X-ray (CXR) is the primary diagnostic tool for community-acquired pneumonia (CAP). Some authors recently proposed that thoracic ultrasound (TUS) could valuably flank or even reliably substitute CXR in the diagnosis and follow-up of CAP. We investigated the clinical utility of TUS in a large sample of patients with CAP, to challenge the hypothesis that it may be a substitute for CXR. METHODS: Out of 645 consecutive patients with a CXR-confirmed CAP diagnosed in the emergency room of our hospital over a three-years period, 510 were subsequently admitted to our department of Internal Medicine. These patients were evaluated by TUS by a well-trained operator who was blinded of the initial diagnosis. TUS scans were performed both at admission and repeated at day 4-6th and 9-14th during stay. RESULTS: TUS identified 375/510 (73.5%) of CXR-confirmed lesions, mostly located in posterior-basal or mid-thoracic areas of the lungs. Pleural effusion was detected in 26.9% of patients by CXR and in 30.4% by TUS. TUS documented the change in size of the consolidated areas as follows: 6.3 ± 3.4 cm at time 0, 2.5 ± 1.8 at 4-6 d, 0.9 ± 1.4 at 9-14 d. Out of the 12 patients with delayed CAP healing, 7 of them turned out to have lung cancer. CONCLUSIONS: TUS allowed to detect lung consolidations in over 70% of patients with CXR-confirmed CAP, but it gave false negative results in 26.5% of cases. Our longitudinal results confirm the role of TUS in the follow-up of detectable lesions. Thus, TUS should be regarded as a complementary and monitoring tool in pneumonia, instead of a primary imaging modality.

MDCT and US of intrathoracic extrapleural space soft tissue-containing lesions: US extrapleural fat sign and MDCT fat ghost ribs sign.

PURPOSE: The purpose of this study was to review the normal anatomy of the extrapleural space, its soft tissue-containing lesions, and to illustrate the extrapleural fat sign with Multidetector Computed Tomography (MDCT) and Ultrasound (US), which was never described so far. MATERIALS AND METHODS: The study includes 28 patients. 24 with histologically or surgically proven extrapleural soft tissue-containing lesions and 4 pleural lesions. Six patients underwent unenhanced MDCT of the chest, while 22 patients had a contrast-enhanced chest MDCT. Furthermore, 9/28 patients underwent Thoracic Ultrasound after MDCT. The lesions included 12 extrapleural hematomas (8 post-traumatic and 4 from other causes), 3 extrapleural lesions from pleural infection extension, 9 extrapleural lesions from metastases. MDCT multiplanar Minimum Intensity Projection (MinIP) reconstructions were always obtained; T-US and MDCT findings were correlated. RESULTS: Among 9 patients who underwent T-US 4/9 showed the "UltraSonography fat extrapleural sign". Among 24 patients who underwent chest MDCT all show the well-known computed tomography (CT) extrapleural fat sign and new auxiliary (MDCT) findings that serve to "strengthen" the diagnosis of correct intrathoracic extrapleural space attribution of lesion. CONCLUSIONS: MDCT with its multiplanar capabilities and post-processing MinIP reconstructions and Thoracic US play a prominent role in the identification and characterization of abnormalities of the frequently overlooked extrapleural space. In conjunction with main CT thoracic findings they provides relevant information in the diagnostic process and correct management.

MDCT distinguishing features of focal aortic projections (FAP) in acute clinical settings.

Focal aortic projections (FAP) are protrusion images of the contrast medium (focal contour irregularity, breaks in the intimal contour, outward lumen bulging or localized blood-filled outpouching) projecting beyond the aortic lumen in the aortic wall and are commonly seen on multidetector computed tomography (MDCT) scans of the chest and abdomen. FAP include several common and uncommon etiologies, which can be demonstrated both in the native aorta, mainly in acute aortic syndromes, and in the post-surgical aorta or after endovascular therapy. They are also found in some types of post-traumatic injuries and in impending rupture of the aneurysms. The expanding, routine use of millimetric or submillimetric collimation of current state-of-the-art MDCT scanners (16 rows and higher) all the time allows the identification and characterization of these small ulcer-like lesions or irregularities in the entire aorta, as either an incidental or expected finding, and provides detailed three-dimensional pictures of these pathologic findings. In this pictorial review, we illustrate the possible significance of FAP and the discriminating MDCT features that help to distinguish among different types of aortic protrusions and their possible evolution. Awareness of some related and distinctive radiologic features in FAP may improve our understanding of aortic diseases, provide further insight into the pathophysiology and natural history, and guide the appropriate management of these lesions.