Extravascular incidental findings in run-off CT angiography in patients with acute limb ischaemia: incidence and clinical relevance

Prevalence of pulmonary nodules detected incidentally on noncancer-related imaging: a review

Pulmonary nodules are common incidental findings requiring surveillance. Follow-up recommendations vary depending on risk factors, size and solid or subsolid characteristics. This review aimed to evaluate the prevalence of clinically significant nodules detected on noncancer-dedicated imaging and the prevalence of part-solid and ground-glass nodules. We conducted a systematic search of literature and screened texts for eligibility. Clinically significant nodules were noncalcified nodules >4-6 mm. Prevalence estimates were calculated for all studies and risk of bias was assessed by one reviewer. Twenty-four studies were included, with a total of 30 887 participants, and 21 studies were cross-sectional in design. Twenty-two studies used computed tomography (CT) imaging with cardiac-related CT being the most frequent. Prevalence of significant nodules was highest in studies with large field of view of the chest and low size thresholds for reporting nodules. The prevalence of part-solid and ground-glass nodules was only described in two cardiac-related CT studies. The overall risk of bias was low in seven studies and moderate in 17 studies. While current literature frequently reports incidental nodules on cardiovascular-related CT, there is minimal reporting of subsolid characteristics. Unclear quantification of smoking history and heterogeneity of imaging protocol also limits reliable evaluation of nodule prevalence in nonscreening cohorts.

Extravascular incidental findings in computed tomography angiography are associated with lower amputation-free survival in patients with acute lower limb ischaemia

BACKGROUND

Emergency computed tomography angiography (CTA) is the most important imaging modality to visualize arterial occlusions in patients with acute lower limb ischaemia (ALI). Extravascular incidental findings (EVIFs) have received less attention.

PURPOSE

The aims of this study were to evaluate the incidence of EVIFs of immediate clinical relevance in patients with ALI undergoing CTA and evaluate the association between EVIFs and emergency revascularization and amputation-free survival at 1 year.

METHODS

Retrospective cohort study. Emergency CTA in patients with ALI between 2015 and 2018 were independently scrutinized by two senior radiologists. EVIFs were classified into immediate (category I), potential (category II) or no clinical relevance (category III). Multi-variable binary logistic regression analysis was expressed in Odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

The intra-class correlation (ICC) coefficient for EVIF category I between the raters was 0.94 (95% CI 0.92-0.96). Among 118 patients with ALI, 78 patients underwent emergency revascularization. Forty-six EVIFs (34 patients) were category I, of which 63% were found in the chest, including pleural effusion (n = 12), pneumonia (n = 8) and cardiac thrombus (n = 4). Ascites (n = 4) and cancer disease (n = 4) were other category I findings. Category I EVIFs were associated with reduced rate of emergency revascularization (OR 0.26, 95% CI 0.10-0.66) and increased rate of combined major amputation/mortality at 1 year (OR 2.9, 95% CI 1.1-8.2) in adjusted analysis.

CONCLUSION

It is important to evaluate EVIFs in emergency CTA in patients with ALI since these findings are both common and associated with reduced emergency revascularization and amputation-free survival at 1 year.

High risk and low prevalence diseases: Acute limb ischemia

INTRODUCTION

Acute limb ischemia is a rare but serious condition that carries with it a high rate of morbidity and mortality.

OBJECTIVE

This review highlights the pearls and pitfalls of acute limb ischemia, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence.

DISCUSSION

Acute limb ischemia is defined as a sudden decrease in limb perfusion resulting in cessation of blood flow and nutrient and oxygen delivery to the tissues. This leads to cellular injury and necrosis, ultimately resulting in limb loss and potentially systemic symptoms with significant morbidity and mortality. There are several etiologies including native arterial thrombosis, arterial thrombosis after an intervention, arterial embolus, and arterial injury. Patients with acute limb ischemia most commonly present with severe pain and sensory changes in the initial stages, with prolonged ischemia resulting in weakness, sensory loss, and color changes to the affected limb. The emergency clinician should consult the vascular specialist as soon as ischemia is suspected, as the diagnosis should be based on the history and examination. Computed tomography angiography is the first line imaging modality, as it provides valuable information concerning the vasculature and surrounding tissues. Doppler ultrasound of the distal pulses may also be obtained to evaluate for arterial and venous flow. Once identified, management includes intravenous unfractionated heparin and vascular specialist consultation for revascularization.

CONCLUSIONS

An understanding of acute limb ischemia can assist emergency clinicians in diagnosing and managing this potentially deadly disease.

Radiomics model using preoperative computed tomography angiography images to differentiate new from old emboli of acute lower limb arterial embolism

Our purpose was to devise a radiomics model using preoperative computed tomography angiography (CTA) images to differentiate new from old emboli of acute lower limb arterial embolism. 57 patients (95 regions of interest; training set: n = 57; internal validation set: n = 38) with femoral popliteal acute lower limb arterial embolism confirmed by pathology and with preoperative CTA images were retrospectively analyzed. We selected the best prediction model according to the model performance tested by area under the curve (AUC) analysis across 1,000 iterations of prediction from three most common machine learning methods: support vector machine, feed-forward neural network (FNN), and random forest, through several steps of feature selection. Then, the selected best model was also validated in an external validation dataset (n = 24). The established radiomics signature had good predictive efficacy. FNN exhibited the best model performance on the training and validation groups: its AUC value was 0.960 (95% CI, 0.899-1). The accuracy of this model was 89.5%, and its sensitivity and specificity were 0.938 and 0.864, respectively. The AUC of external validation dataset was 0.793. Our radiomics model based on preoperative CTA images is valuable. The radiomics approach of preoperative CTA to differentiate new emboli from old is feasible.

Influence of diabetes on diagnostic performance of computed tomography angiography of the calf arteries in acute limb ischemia

BACKGROUND

Patients with diabetes mellitus (DM) have a more extensive distal arterial occlusive disease compared to non-diabetic patients. Diagnostic imaging is a necessity to identify the location and extent of the arterial occlusion in acute limb ischemia (ALI). Computed tomography angiography (CTA) is the most commonly used modality and the diagnostic performance with CTA of calf arteries may be questioned.

PURPOSE

To evaluate diagnostic performance of CTA of calf arteries in ALI and to compare patients with and without DM.

MATERIAL AND METHODS

All thrombolytic treatments performed during 2001-2018 in patients with ALI were included. Initial digital subtraction angiography (DSA) and CTA of all patients were classified according to the Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) below-the-knee arteries and compared to CTA. Two raters assessed the CTA images independently. Inter-rater reliability was expressed as intraclass correlation (ICC) with 95% confidence intervals (CI).

RESULTS

Patients with (n = 23) and without (n = 85) DM had lower (P = 0.006) glomerular filtration rate. ICC between CTA and DSA was 0.33 (95% CI -0.22 to 0.56) and 0.71 (95% CI 0.38-0.68) in patients with and without DM, respectively. Sensitivity with CTA for TASC D lesions in patients with and without DM was 0.14 (95% CI -0.12 to 0.40) and 0.64 (95% CI 0.48-0.80), respectively.

CONCLUSION

The sensitivity of CTA for assessment of infra-popliteal TASC D lesions in patients with ALI was not acceptable in patients with DM in contrast to those without DM. Another imaging option at present times should be considered for patients with DM.

Performance of Computed Tomography Angiography Before Revascularization Is Associated With Higher Amputation-Free Survival in Rutherford IIb Acute Lower Limb Ischaemia

Background: Acute lower limb ischemia with a motor deficit (Rutherford IIb) needs urgent revascularization to avoid major amputation and mortality. It is unclear whether immediate revascularization without performing CT angiography (CTA) prior to revascularization in Rutherford IIb acute lower limb ischemia (ALI) is associated with better outcomes. Methods: Retrospective observational study of Rutherford IIb ALI patients treated between 2006 and 2018. A propensity score adjusted analysis was performed to compare outcomes after the performance of CTA examination or not. Results: Among 681 patients, 260 had Rutherford IIb ALI. CTA prior to revascularization was performed in 131 (50.4%) and increased (p < 0.001) throughout the study period. Open vascular and endovascular surgery was first performed in 147 (56.5%) and 113 (43.5%) patients, respectively. The proportion of endovascular treatment increased while the open vascular surgery decreased during the study period (p = 0.031). In the propensity score adjusted analysis, the performance of CTA was associated with decreased risk of combined major amputation /mortality (odds ratio 0.52, 95% confidence interval 0.27-0.99; p = 0.046) at 1 year. Conclusion: Performance of CTA was associated with a higher amputation-free survival in revascularized patients with Rutherford IIb ALI. CTA seem to provide guidance in selecting the most appropriate candidates for revascularization and choice of technique.

Patients with atherosclerotic peripheral arterial disease have a high risk of lung cancer: Systematic review and meta-analysis of literature

PURPOSE

Lung cancer and atherosclerosis share common risk factors. Literature data suggest that the prevalence of lung malignancy in patients with peripheral arterial disease (PAD) is higher than in the general population. Our goal was to determine, through a systematic literature review, the prevalence of lung cancer in patients with PAD.

METHODS

We consulted available publications in the Cochrane library, MEDLINE, PUBMED, EMBASE, and ClinicalTrials.gov. We included all articles, written in English or French, published between 1990 and 2020 reporting the prevalence of lung cancer in patients with PAD (atherosclerotic aortic aneurysm or peripheral occlusive diseases). Patients with coronary artery disease, cardiac valvulopathy or carotid stenosis were not included. We did not include case reports. We performed a critical analysis of each article. Data were collected from two independent readers. A fixed effect model meta-analysis allowed to estimate a summary prevalence rate.

RESULTS

We identified 303 articles, and selected 19 articles according to selection criteria. A total of 16849 patients were included (mean age 68.3 years, 75.1% of males). Aortic aneurysms were found in 29% of patients and atherosclerotic occlusive disease in 66% of patients. Lung cancer was identified in 538 patients, representing a prevalence of 3%.

DISCUSSION

Lung cancer is found in 3% of patients with atherosclerotic PAD. This prevalence is higher than that found in lung cancer screening programs performed in the general population of smokers and former smokers. These patients should be screened for lung cancer. Their selection may dramatically increase the benefit of lung cancer screening.

Extravascular findings on run-off MR angiography: frequency, location and clinical significance

OBJECTIVES

The aim of this study was to analyze the prevalence, location and clinical relevance of extravascular findings (EVFs) on magnetic resonance angiography (MRA) of the run-off vasculature.

METHODS

In this retrospective study, we analyzed run-off MRAs of 194 consecutive patients (45 women and 149 men, median age 68 years, IQR 58-74 years). Our patient cohort consisted predominantly of individuals with known (n = 165, 85%) or suspected (n = 15, 8%) peripheral artery disease (PAD). All MRA examinations were performed between 2012 and 2018 on a 3 Tesla MRI scanner using a standardized protocol. Two radiologists re-evaluated the MRA images to identify EVFs, which were classified into findings with major (category I), moderate (category II) and minor (category III) clinical significance.

RESULTS

A total of 501 EVFs were found in 172 of the 194 patients (89%). Twenty-seven findings (5%) were assigned to category I, 189 (38%) to category II and 285 (57%) to category III. 23 of 194 patients (12%) had at least one EVF with major clinical relevance (category I). Most of the 27 category I EVFs were observed in the soft tissues (n = 13, 48%). The remaining category I EVFs were found in the musculoskeletal (n = 7, 26%), urogenital (n = 4, 15%), lymphatic (n = 2, 7%) and gastrointestinal (n = 1, 4%) system. The majority of the category I EVFs were infectious (n = 14, 52%) or neoplastic (n = 10, 37%) pathologies.

CONCLUSIONS

Clinically relevant EVF can be encountered frequently on run-off MRA examinations. These results illustrate the importance of evaluating all organ systems when reporting MRA examinations, despite the clinical focus being the patients' vascular status.

Extravascular findings during upper limb computed tomographic angiography focusing on undiagnosed malignancy

BACKGROUND

Computer tomography angiography (CTA) has been an established method for diagnostic vascular disease of lower limbs. Recently, the method is widely used for diagnosis of vascular pathologies in the upper limbs too. It also has increased the possibilities of this scans being reviewed by no specially trained radiologists. This increases the risk of incidental non vascular findings to be missed or misinterpreted. The study is focusing in the frequency of extravascular incidental finding (EVIF) and highlights the importance for both the reporting radiologist and the referring physician recognizing the frequency of EVIFs.

AIM

To analyse the frequency of EVIF identified on computed angiography (CT) of the upper limb.

METHODS

A total of 1383 CT angiographic studies of the peripheral arterial system were performed between August 2015 and August 2017. All upper limb CTAs (n = 79) were retrospectively reviewed for the presence of non-vascular incidental findings within the chest, abdomen/pelvis, musculoskeletal system or head and neck. These EVIFs were subsequently grouped into 3 categories based on clinical significance. EVIFs of immediate clinical relevance were included in category A, findings considered indeterminate but most likely benign were placed in category B, while incidental findings of no clinical significance were included in category C.

RESULTS

Complete imaging datasets were available in 74/79 (93.7%). Patient demographics included 39 (52.7%) females and 35 (47.2%) males with a mean age of 59 ± 19.5 years (range 19-93 years). A total of 153 EVIFs were reported in 52 patients (70.3%). Of these, 44 EVIFs (28.7%) were found in the chest, 83 (54.2%) in the abdomen, 14 (9.2%) in the musculoskeletal system and 9 (5.8%) in the head and neck. Thirteen EVIFs (8.4%) identified in 11 patients were noted to be of immediate clinical significance (Category A), 50 EVIFs (32.3%) were identified in 20 patients and were considered indeterminate but most likely benign, while the remaining 91 EVIFs (59.5%) identified in 21 patients were determined to be of no clinical significance (Category C). One index case of malignancy (1.3%) and four cases of new disseminated metastatic disease (5.4%) were identified.

CONCLUSION

Our study of upper limb CTA examinations demonstrated a frequency of 8.4% for extravascular incidental findings of immediate clinical significance. We highlight the importance for both the reporting radiologist and the referring physician of the need to recognize the frequency with which EVIFs are identified in the upper limb peripheral arterial system and of the necessity for further clinical and imaging work-up.

Visualization of the peripheral vascularity by time-resolved computed tomography: a case report

Runoff computed tomography angiography (CTA) is commonly used to diagnose peripheral artery disease (PAD) of the lower extremities. However, the risk of non-conclusive examination due to suboptimal timing and overrunning the contrast medium bolus is a major pitfall that must be considered. Here we describe two case studies using dynamic time-resolved CTA imaging of the peripheral vascularity.

Incidental extravascular findings in CT angiograms in patients post endovascular abdominal aortic aneurysm repair: clinical relevance and frequency

Background

To evaluate the incidence and clinical relevance of extravascular incidental findings (EVIF), particularly malignancies, in planning and follow-up CT angiograms (CTA) of the abdominal aorta in patients who underwent endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm. Retrospective study of 2203 planning and follow-up CTAs of 418 patients who underwent EVAR in a single tertiary centre between 2006 and 2015. CTA reports were scrutinized for EVIFs, which were classified according to clinical relevance, into (I) immediate, (II) potential and (III) no clinical relevance. Clinical follow-up and management were reviewed for significant findings. Follow-up CTAs of patients with incidental malignancies were re-reviewed by two consultant radiologists to evaluate if early missed malignant findings on previous CTAs were present.

Results

In total, 950 EVIFs were noted in 418 patients [31 females (7.4%), 387 males (92.6%); age range 63–93, mean age 79.0 years]. The number of patients with findings in each category were; Category I (115), Category II (165), Category III (304). Incidental malignant findings were reported in 51 patients (12.2%), of which 27 were noted on the initial CTA (6.5%) and 24 on follow-up CTAs (5.7%). Of the 24 patients with malignancies on follow-up CTAs, 13 had early malignant findings missed or misinterpreted on previous CTAs, while 11 had no significant abnormality even on retrospective review.

Conclusion

A high number of significant EVIFs, particularly incidental malignancies, can be identified in follow-up CTAs of patients who undergo EVAR. Specific ‘review areas’ when reporting surveillance CTAs can be recommended based on the findings of our study.

Run-Off Computed Tomography Angiography (CTA) for Discriminating the Underlying Causes of Intermittent Claudication

AIM

To evaluate run-off computed tomography angiography (CTA) of abdominal aorta and lower extremities for detecting musculoskeletal pathologies and clinically relevant extravascular incidental findings in patients with intermittent claudication (IC) and suspected peripheral arterial disease (PAD). Does run-off CTA allow image-based therapeutic decision making by discriminating the causes of intermittent claudication in patients with suspected peripheral arterial disease PAD?

MATERIAL AND METHODS

Retrospective re-evaluation of CTAs performed in patients with acute or chronic intermittent claudication (i.e., Fontaine stages I to IIB) between January 2005 and October 2013. Allocation to one of three categories of underlying causes of IC symptoms: vascular, musculoskeletal (MSK) or both. Clinically relevant extravascular incidental findings were evaluated. Medical records were reviewed to verify specific therapies as well as main and incidental findings.

RESULTS

While focused on vascular imaging, CTA image quality was sufficient for evaluation of the MSK system in all cases. The underlying cause of IC was diagnosed in run-off CTA as vascular, MSK and a combination in n = 138 (65%), n = 10 (4%), and n = 66 (31%) cases, respectively. Specific vascular or MSK therapy was recorded in n = 123 and n = 9 cases. In n = 82, no follow-up was possible. Clinically relevant extravascular incidental findings were detected in n = 65 patients (30%) with neoplasia, ascites and pleural effusion being the most common findings.

DISCUSSION

Run-off CTA allows identification of vascular, MSK, and combined causes of IC in patients with suspected PAD and can guide specific therapy. CTA also allowed confident detection of crEVIF although detection did not necessarily trigger workup or treatment.