Recurrent non-rheumatic streptococcal myocarditis: 18F-FDG PET/CMR findings

Nonrheumatic streptococcal myocarditis (NRSM) is a life-threatening complication of streptococcal pharyngitis. We report the history of a 35-year-old man with recurrent NRSM and the related 18F-FDG PET/CMR findings.18F-FDG PET/CMR represents cutting-edge imaging for the diagnosis and follow-up of myocarditis, allowing myocardial inflammation assessment, and the distinction between active disease and myocardial scarring.

Cutting-Edge Imaging of Cardiac Metastases from Neuroendocrine Tumors: Lesson from a Case Series

With the increasing availability of high-performance medical imaging for the management of patients with neuroendocrine tumors (NETs), a progressive growth of asymptomatic and incidentally detected cardiac metastases (CMs) has been observed in the recent years. In clinical practice, CMs of NENs are often incidentally detected by whole-body 68Ga-labeled somatostatin analogs or 18F-fluorodihydroxyphenylalanine positron emission tomography/computed tomography, and afterwards accurately characterized by cardiac magnetic resonance (CMR) and/or gated cardiac computed tomography when CMR is contraindicated or not available. The interpreting physician should familiarize with the main imaging features of CM, a finding that may be encountered in NETs patients more than previously thought. Herein, we present a case series of four patients with CMs from small-intestine NETs highlighting strengths and weaknesses of a multimodality imaging approach in clinical practice.

Deep Learning Supplants Visual Analysis by Experienced Operators for the Diagnosis of Cardiac Amyloidosis by Cine-CMR

Background: Diagnosing cardiac amyloidosis (CA) from cine-CMR (cardiac magnetic resonance) alone is not reliable. In this study, we tested if a convolutional neural network (CNN) could outperform the visual diagnosis of experienced operators. Method: 119 patients with cardiac amyloidosis and 122 patients with left ventricular hypertrophy (LVH) of other origins were retrospectively selected. Diastolic and systolic cine-CMR images were preprocessed and labeled. A dual-input visual geometry group (VGG ) model was used for binary image classification. All images belonging to the same patient were distributed in the same set. Accuracy and area under the curve (AUC) were calculated per frame and per patient from a 40% held-out test set. Results were compared to a visual analysis assessed by three experienced operators. Results: frame-based comparisons between humans and a CNN provided an accuracy of 0.605 vs. 0.746 (p < 0.0008) and an AUC of 0.630 vs. 0.824 (p < 0.0001). Patient-based comparisons provided an accuracy of 0.660 vs. 0.825 (p < 0.008) and an AUC of 0.727 vs. 0.895 (p < 0.002). Conclusion: based on cine-CMR images alone, a CNN is able to discriminate cardiac amyloidosis from LVH of other origins better than experienced human operators (15 to 20 points more in absolute value for accuracy and AUC), demonstrating a unique capability to identify what the eyes cannot see through classical radiological analysis.

Classification of Cardiomyopathies from MR Cine Images Using Convolutional Neural Network with Transfer Learning

The automatic classification of various types of cardiomyopathies is desirable but has never been performed using a convolutional neural network (CNN). The purpose of this study was to evaluate currently available CNN models to classify cine magnetic resonance (cine-MR) images of cardiomyopathies. Method: Diastolic and systolic frames of 1200 cine-MR sequences of three categories of subjects (395 normal, 411 hypertrophic cardiomyopathy, and 394 dilated cardiomyopathy) were selected, preprocessed, and labeled. Pretrained, fine-tuned deep learning models (VGG) were used for image classification (sixfold cross-validation and double split testing with hold-out data). The heat activation map algorithm (Grad-CAM) was applied to reveal salient pixel areas leading to the classification. Results: The diastolic–systolic dual-input concatenated VGG model cross-validation accuracy was 0.982 ± 0.009. Summed confusion matrices showed that, for the 1200 inputs, the VGG model led to 22 errors. The classification of a 227-input validation group, carried out by an experienced radiologist and cardiologist, led to a similar number of discrepancies. The image preparation process led to 5% accuracy improvement as compared to nonprepared images. Grad-CAM heat activation maps showed that most misclassifications occurred when extracardiac location caught the attention of the network. Conclusions: CNN networks are very well suited and are 98% accurate for the classification of cardiomyopathies, regardless of the imaging plane, when both diastolic and systolic frames are incorporated. Misclassification is in the same range as inter-observer discrepancies in experienced human readers.

Presence of active myocarditis at the 6 month follow-up appointment for a severe form of COVID-19: a case report

Here, we present the case of an 81‐year‐old male patient, who was hospitalized for a severe form of COVID‐19. Transthoracic echocardiogram (TTE) performed 1 month after symptom onset was normal. Respiratory evolution was favourable, and the patient was discharged at Day 78. At 6 months, despite a good functional recovery, he presented pulmonary sequelae, and the TTE revealed a clear reduction of left ventricular ejection fraction (LVEF) and mild LV dilatation without cardiac symptoms. The cardiac magnetic resonance (CMR) using Lake Louise Criteria (LLC), T1 and T2 mapping showed focal infero‐basal LV wall oedema, elevated T1 and T2 myocardial relaxation times especially in basal inferior and infero‐lateral LV walls, and sub‐epicardial late gadolinium enhancement in those LV walls. The diagnosis of active myocarditis was raised especially based on TTE abnormalities and CMR LLC, T1 and T2 mapping. Currently, we are not aware of published reports of a 6 month post‐COVID‐19 active myocarditis.

Advantages of 18F-FDG PET/CT Imaging over Modified Duke Criteria and Clinical Presumption in Patients with Challenging Suspicion of Infective Endocarditis

According to European Society of Cardiology guidelines (ESC2015) for infective endocarditis (IE) management, modified Duke criteria (mDC) are implemented with a degree of clinical suspicion degree, leading to grades such as "possible" or "rejected" IE despite a persisting high level of clinical suspicion. Herein, we evaluate the ¹⁸F-FDG PET/CT diagnostic and therapeutic impact in IE suspicion, with emphasis on possible/rejected IE with a high clinical suspicion. Excluding cases of definite IE diagnosis, 53 patients who underwent ¹⁸F-FDG PET/CT for IE suspicion were selected and afterwards classified according to both mDC (possible IE/Duke 1, rejected IE/Duke 0) and clinical suspicion degree (high and low IE suspicion). The final status regarding IE diagnosis (gold standard) was based on the multidisciplinary decision of the Endocarditis Team, including the 'imaging specialist'. PET/CT images of the cardiac area were qualitatively interpreted and the intensity of each focus of extra-physiologic ¹⁸F-FDG uptake was evaluated by a maximum standardized uptake value (SUVmax) measurement. Extra-cardiac ¹⁸F-FDG PET/CT pathological findings were considered to be a possible embolic event, a possible source of IE, or even a concomitant infection. Based on the Endocarditis Team consensus, final diagnosis of IE was retained in 19 (36%) patients and excluded in 34 (64%). With a sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and global accuracy of 79%, 100%, 100%, 89%, and 92%, respectively, PET/CT performed significantly better than mDC (p = 0.003), clinical suspicion degree (p = 0.001), and a combination of both (p = 0.001) for IE diagnosis. In 41 patients with possible/rejected IE but high clinical suspicion, sensitivity, specificity, PPV, NPV, and global accuracies were 78%, 100%, 100%, 85%, and 90%, respectively. Moreover, PET/CT contributed to patient management in 24 out of 53 (45%) cases. ¹⁸F-FDG PET/CT represents a valuable diagnostic tool that could be proposed for challenging IE cases with significant differences between mDC and clinical suspicion degree. ¹⁸F-FDG PET/CT allows a binary diagnosis (definite or rejected IE) by removing uncertain diagnostic situations, thus improving patient therapeutic management.

Acute Myopericarditis in a Patient With Mild SARS-CoV-2 Respiratory Infection

Herein is presented a case of a 71-year-old woman with mild SARS-CoV-2 respiratory infection who experienced acute myopericarditis diagnosed using clinical, biological, and electrocardiogram data and cardiac magnetic resonance imaging. The presented case highlights the risk of cardiac involvement, even in the absence of severe respiratory COVID-19 infection. The mechanisms involved in acute myocardial injury in SARS-CoV-2 infection are not well known and requires further studies to determine whether it is related to direct myocardial damage by the virus or to a systemic condition.

T1 mapping cardiac magnetic resonance imaging frequently detects subclinical diffuse myocardial fibrosis in systemic sclerosis patients

OBJECTIVES

cardiac involvement is the second most frequent systemic sclerosis (SSc) related cause of death. It remains mostly asymptomatic in the early stage and is underdiagnosed with routine screening. Cardiac magnetic resonance imaging (CMR) could improve cardiac assessment of patients and noteworthily, new sequences allow the detection of diffuse myocardial fibrosis (DMF) by native T1 mapping. The aim of this study was to determine the prevalence of cardiac involvement by CMR native T1 mapping and its correlation with echocardiography data and non-cardiac manifestations in SSc patients.

METHODS

patients fulfilling the ACR/EULAR classification criteria for SSc were prospectively included between 2014 and 2016. They underwent CMR at 1.5T, including native T1 and T2 mapping, and Late Gadolinium Enhancement (LGE) as a part of routine follow up. Routine biological tests (mainly BNP and CRP) were centralized in the hospital laboratory.

RESULTS

seventy-two unselected patients were included. Thirty six patients (50%) had elevated T1 (ET1) (mean T1 1097±14 ms). CMR cardiac functional parameters were similar in ET1 and normal T1 (NT1). Echocardiography was normal in 18 (50%) of ET1. ET1 and NT1 groups were similar for cardiovascular risk factors and ischemic heart disease. ET1 was not correlated with any clinical or echocardiographic parameter or antibody profile. Thirty-six percent of patients with ET1 had no cardiac symptoms, normal echocardiography and CMR LVEF, and no LGE.

CONCLUSION

native T1 mapping detects left ventricular ET1 (potential DMF) in 50% of patients with SSc and a third of them had a normal conventional screening including standard CMR. In the future, further studies are needed to confirm the benefit of use of native T1 mapping as a part of routine follow up to detect earlier pejorative cardiac involvement in SSc patients.

320-row CT transcatheter aortic valve replacement planning with a single reduced contrast media bolus injection

OBJECTIVE

To reduce the iodine load required for CT Transcatheter Aortic Valve Replacement (TAVR) planning on a 320-row scanner by acquiring the two CT TAVR steps (ECG-gated aortic root CTA and non-gated aorto-ilio-femoral CTA) within a single contrast media bolus injection.

METHODS

50 consecutive patients (82.6±6.9 years; 56% female) were prospectively enrolled and underwent a TAVR planning using a 320-row CT, with ECG-gated aortic root CTA immediately followed by a non-gated aorto-iliac acquisition, all within a single bolus of 40-70mL of Iohexol 350mgI/mL. The Iodine load, image quality, SNR, CNR and radiation dose were compared using a Mann-Whitney test to that of 24 consecutive patients (84.3±4.8 years, 58% female) previously imaged on a 64-row scanner with a conventional two-step protocol.

RESULTS

Iodine load was reduced by 44%. All examinations were of diagnostic quality, with improvement of the aortic root CTA image quality (4.9±0.3 versus 4.6±0.5, p<0.01) and a non-significant decrease of the aorto-iliac CTA image quality (4.7±0.6 versus 4.9±0.3, p = 0.07). SNR and CNR were significantly improved in the aortic root CTA (14.0±5.3 and 10.4±4.5 versus 10.3±4.2 and 6.8±3.3, p<0.01 for both) and non-significantly higher in the aorto-iliac CTA (16.5±8.0 and 14.1±7.9 versus 14.7±5.5 and 12.5±5.0, p = 0.42 and p = 0.66). Total radiation dose was reduced by 32%.

CONCLUSION

320-row CT scanner enables a 44% reduction of iodine load in TAVR planning, while maintaining excellent aorto-ilio-femoral arterial enhancement and lowering radiation dose.

The extent of P2Y12 inhibition by clopidogrel in diabetes mellitus patients with acute coronary syndrome is not related to glycaemic control: Roles of white blood cell count and body weight

It was the study objective to determine whether glycaemic control affects the extent of platelet inhibition by thienopyridines as assessed by vasodilator-stimulated phosphoprotein flow cytometry (VASP-FCT) in patients with diabetes mellitus (DM) undergoing percutaneous coronary intervention (PCI) during acute coronary syndrome (ACS). Although the proportion of high on-treatment residual platelet reactivity is higher in DM, the contributions of glycaemic control and other factors associated with DM, such as excess body weight and inflammation, to this impaired platelet inhibition by thienopyridines have not yet been fully characterised. In this study, the extent of P2Y12 ADP receptor pathway inhibition was evaluated by the VASP-FCT. Platelet activation was expressed as the platelet reactivity index (PRI). Low response to clopidogrel (LR) was defined as a PRI of >61%. Four hundred forty-five consecutive ACS patients (DM = 160, NDM = 285) were enrolled. The proportion of LR was higher in DM patients (50 vs. 37.5%). In DM, PRI was not correlated with glycosylated haemoglobin (HbA1c) or glycaemia. In a univariate analysis, LR was associated with age, male sex, overweight, and white blood cell count (WBC). In a multivariate analysis, WBC >10,000 and body weight >80 kg were the sole independent predictors of LR to clopidogrel (hazard ratio (HR) 3.02 [1.36–6.68], p=0.006 and HR 2.47 [1.14–5.35], p = 0.021, respectively). Conversely, in non-DM patients, ST-elevation myocardial infarction was the sole independent predictor of LR. In conclusion, in ACS DM patients undergoing PCI, the extent of P2Y12 inhibition by clopidogrel is not related to glycaemic control but is related to body weight and inflammatory status as assessed by the WBC.

A dual flip angle 3D bSSFP magnetization transfer-like method to differentiate between recent and old myocardial infarction

BACKGROUND

Magnetic resonance imaging (MRI) tissue signal is modulated by magnetization transfer (MT) phenomena, intrinsically induced by balanced steady-state free precession (bSSFP) imaging.

PURPOSE

To investigate the possible value of such a MT-like bSSFP approach in two clinical settings involving focal myocardial lesions highligthed by late gadolinium enhancement (LGE+): edema induced by recent myocardial infarction (MI) and fibrotic scar related to chronic infarction.

MATERIALS AND METHODS

Population: 48 LGE + patients were studied: 26 with recent MI, 22 with chronic MI. 20 LGE-normal subjects were considered the control group. Field strength/sequence: Navigator-based short axis 3D-bSSFP sequences with 20° and 90° excitation flip angles were acquired (1.5T).

ASSESSMENT

Pixel-wise normalized MT Ratio (nMTR) parametric images were calculated according to: nMTR = 100*(S₂₀ -S₉₀ *k)/S₂₀ , with S₂₀ and S₉₀ signal intensity in 20° and 90° flip angle images and k = Blood₂₀ /Blood₉₀ as a normalization ratio. Statistical tests: analysis of variance (ANOVA), receiver operating characteristic (ROC) analysis.

RESULTS

Overall normal myocardial nMTR was 50.2 ± 3.6%. In recent MI, nMTR values were significantly reduced in LGE + regions (-22.3 ± 9.9%, P < 0.0001). In cases of chronic infarct, nMTR was significantly increased in LGE + regions (14.2 ± 11.4%, P < 0.0001). Comparison between observed results and theoretical values obtained with the Freeman-Hill formula showed that most variations observed in MI are related to MT effects instead of relaxation effects.

CONCLUSION

In contrast to LGE imaging, which may show a similar hyperenhancement in recent and old infarctions, nMTR imaging demonstrates an opposite pattern: decreased values for recent infarction and increased values for old infarction, thus allowing to discriminate between these two clinical conditions without gadolinium injection.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:798-808.

Longitudinal 2D strain can help diagnose coronary artery disease in patients with suspected non-ST-elevation acute coronary syndrome but apparent normal global and segmental systolic function

BACKGROUND

The clinical work-up of patients presenting with chest pain is a diagnostic challenge. We investigated the diagnostic performance of global (GLS) and territorial (TLS) longitudinal strain to predict coronary artery disease (CAD) in patients presenting with suspected non-ST-segment elevation acute coronary syndrome (NSTE-ACS) but apparent normal global and regional systolic function.

METHODS

150 consecutive suspected NSTE-ACS patients were initially screened for inclusion ; 58 patients with normal LVEF (≥55%) and WMSI (=1) were prospectively enrolled. Speckle-tracking echocardiography was performed on admission and all the patients underwent coronary angiography. CAD was defined as the presence of stenosis of >50%.

RESULTS

CAD was present in 33 patients (57%). LVEF was 60.7±4.6% in group 1 (CAD) and 61.1±5.0% in group 2 (no CAD). Global longitudinal strain (GLS) was altered in group 1 (-16.7±3.4%) as compared to group 2 (-22.4±2.9%, p<0.001). ROC curve analysis showed a high diagnostic value of GLS for the prediction of CAD (AUC=0.92 [0.84-1.00], p=0.0001). TLS was able to discriminate between coronary stenosis in the LAD, LCX or RCA.

CONCLUSIONS

Longitudinal 2D strain has a good diagnostic value and can efficiently localize the culprit lesion in patients presenting with NSTE-ACS but apparent normal global and regional systolic function.

Magnetic resonance evaluation of cardiac thrombi and masses by T1 and T2 mapping: an observational study

The purpose of this work was to evaluate CMR T1 and T2 mapping sequences in patients with intracardiac thrombi and masses in order to assess T1 and T2 relaxometry usefulness and to allow better etiological diagnosis. This observational study of patients scheduled for routine CMR was performed from September 2014 to August 2015. All patients referred to our department for a 1.5 T CMR were screened to participate. T1 mapping were acquired before and after Gadolinium injection; T2 mapping images were obtained before injection. 41 patients were included. 22 presented with cardiac thrombi and 19 with cardiac masses. The native T1 of thrombi was 1037 ± 152 ms (vs 1032 ± 39 ms for myocardium, p = 0.88; vs 1565 ± 88 ms for blood pool, p < 0.0001). T2 were 74 ± 13 ms (vs 51 ± 3 ms for myocardium, p < 0.0001; vs 170 ± 32 ms for blood pool, p < 0.0001). Recent thrombi had a native T1 shorter than old thrombi (911 ± 177 vs 1169 ± 107 ms, p = 0.01). The masses having a shorter T1 than the myocardium were lipomas (278 ± 29 ms), calcifications (621 ± 218 ms), and melanoma (736 ms). All other masses showed T1 values higher than myocardial T1, with T2 consistently >70 ms. T1 and T2 mapping CMR sequences can be useful and represent a new approach for the evaluation of cardiac thrombi and masses.

Left Ventricular Function Evaluation on a 3T MR Scanner with Parallel RF Transmission Technique: Prospective Comparison of Cine Sequences Acquired before and after Gadolinium Injection

Objectives

To compare cine MR b-TFE sequences acquired before and after gadolinium injection, on a 3T scanner with a parallel RF transmission technique in order to potentially improve scanning time efficiency when evaluating LV function.

Methods

25 consecutive patients scheduled for a cardiac MRI were prospectively included and had their b-TFE cine sequences acquired before and right after gadobutrol injection. Images were assessed qualitatively (overall image quality, LV edge sharpness, artifacts and LV wall motion) and quantitatively with measurement of LVEF, LV mass, and telediastolic volume and contrast-to-noise ratio (CNR) between the myocardium and the cardiac chamber. Statistical analysis was conducted using a Bayesian paradigm.

Results

No difference was found before or after injection for the LVEF, LV mass and telediastolic volume evaluations. Overall image quality and CNR were significantly lower after injection (estimated coefficient cine after > cine before gadolinium: -1.75 CI = [-3.78;-0.0305], prob(coef>0) = 0% and -0.23 CI = [-0.49;0.04], prob(coef>0) = 4%) respectively), but this decrease did not affect the visual assessment of LV wall motion (cine after > cine before gadolinium: -1.46 CI = [-4.72;1.13], prob(coef>0) = 15%).

Conclusions

In 3T cardiac MRI acquired with parallel RF transmission technique, qualitative and quantitative assessment of LV function can reliably be performed with cine sequences acquired after gadolinium injection, despite a significant decrease in the CNR and the overall image quality.

Multimodality Imaging Diagnostic Approach of Systemic-to-Pulmonary Vein Fistulae

A 26-year-old man with a history of bilateral lung transplantation for pulmonary cystic fibrosis 6 months before was admitted in our institution for acute heart failure. Cardiac magnetic resonance imaging (CMR) showed an increased aortic output, as aortic flow assessed by velocity mapping was twofold the pulmonary flow, an occluded superior vena cava (SVC), and enlarged azygos vein. A systemic-to-pulmonary vein fistula (SAPVF) was suspected. The selective angiography showed numerous fistulae between intercostals, thyro-cervical, internal mammary arteries and pulmonary veins. The thoracic CT performed before the CMR, which was initially considered as normal, showed well these arteriovenous fistulae after 3D MIP reconstruction. This particular observation highlights the great value of multimodality imaging for the diagnosis of this rare pathology. The MR velocity mapping is a noninvasive imaging technique of great interest to guide the diagnosis of arteriovenous fistulae, and further indicating more invasive complementary imaging modalities like selective arterial angiography.

Left ventricular involvement in arrhythmogenic right ventricular cardiomyopathy - a cardiac magnetic resonance imaging study

BACKGROUND

Few studies evaluated left ventricular (LV) involvement in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). The aim of this study is to determine the frequency, clinical presentation, and pattern of LV involvement in ARVD/C (LV-ARVD/C).

METHODS

We retrospectively evaluated the cardiac magnetic resonance (CMR) in 202 patients referred between 2008 and 2012 to our institution, and we determined the presence or the absence of CMR criteria in the revised task force criteria 2010 for the diagnosis of ARVD/C. A total of 21 patients were diagnosed with ARVD/C according to the revised task force criteria 2010. All included patients had no previous history of myocarditis, acute coronary syndrome, or any other cardiac disease that could interfere with the interpretations of structural abnormalities. The LV involvement in ARVD/C was defined by the presence of one or more of the following criteria: LV end-diastolic volume (LVEDV; >95 mL/m²), LV ejection fraction (LVEF; <55%), LV late enhancement of gadolinium (LVLE) in a non-ischemic pattern, and LV wall motion abnormalities (WMAs). In the follow-up for the occurrence of cardiac death, ventricular tachycardia (VT) was obtained at a mean of 31 ± 20.6 months.

RESULTS

A total of 21 patients had ARVD/C. The median age was 48 (33–63) years. In all, 11 patients (52.4%) had LV-ARVD/C. The demographic characteristics of patients with or without LV were similar. There was a higher frequency of left bundle-branch block (LBBB) VT morphology in ARVD/C (P = 0.04). In CMR, regional WMAs of right ventricle (RV) and RV ejection fraction (RVEF; <45%) were strongly correlated with LV-WMAs (r = 0.72, P = 0.02, r = 0.75, P = 0.02, respectively). RV late enhancement of gadolinium (RVLE) was associated with LV-WMs and LVLE (r = 0.7, P = 0.03; r = 0.8, P = 0.006). LVLE was associated with LV-WMAs, LVEF, and LVEDV (r = 0.9, P = 0.001; r = 0.8, P = 0.001; r = 0.8, P = 0.01).

CONCLUSION

LV involvement in ARVD/C is common and frequently associated with moderate to severe right ventricular (RV) abnormalities. The impact of LV involvement in ARVD/C on the prognosis needs further investigations.

Native T1 mapping of the heart - a pictorial review

T1 mapping is now a clinically feasible method, providing pixel-wise quantification of the cardiac structure’s T1 values. Beyond focal lesions, well depicted by late gadolinium enhancement sequences, it has become possible to discriminate diffuse myocardial alterations, previously not assessable by noninvasive means. The strength of this method includes the high reproducibility and immediate clinical applicability, even without the use of contrast media injection (native or pre-contrast T1). The two most important determinants of native T1 augmentation are (1) edema related to tissue water increase (recent infarction or inflammation) and (2) interstitial space increase related to fibrosis (infarction scar, cardiomyopathy) or to amyloidosis. Conversely, lipid (Anderson–Fabry) or iron overload diseases are responsible for T1 reduction. In this pictorial review, the main features provided by native T1 mapping are discussed and illustrated, with a special focus on the awaited clinical purpose of this unique, promising new method.

Detailed cross-sectional study of 60 superficial femoral artery occlusions: morphological quantitative analysis can lead to a new classification

OBJECTIVE

Current clinical classification of superficial femoral artery (SFA) occlusions as defined by TASC II guidelines is limited to length and calcifications analysis on 2D angiograms, while state-of-the-art cross-sectional imaging like computed tomography angiography (CTA) and magnetic resonance angiography (MRA) provides much more detailed anatomical information than traditional invasive angiography: quantitative morphological analysis of these advanced imaging techniques could therefore be the basis of a refined classification.

METHODS AND RESULTS

Forty-six patients (65% men, 68±11.6 years) that underwent lower limb CTA were retrospectively included, totalizing 60 SFA occlusions. Lesions were classified as TASC II stage A in 3% of cases, stage B in 20%, stage C in 2% and stage D in 75%. For each pathological artery, curved multiplanar reconstructions following the occluded SFA course were used to measure the total length and the mean diameter of the occluded segment. Color-coded map provided an accurate estimation of calcifications' volume. Thirty-nine percent of the occlusions were total. Mean occluded segment length was 219±107 mm (range, 14-530 mm); mean occluded segment diameter was 6.1±1.6 mm (range, 3.4-10 mm); mean calcifications' volume in the occluded segment was 1,265±1,893 mm(3) (range, 0-8,815 mm(3)), corresponding to a percentage of 17.4%±20% (range, 0-88.7%). Shrinked occluded occlusions were defined by a mean diameter under 5 mm and heavily calcified occlusions by a mean percentage of calcifications above 4%. Use of these thresholds allowed the distinction of four groups of patients: heavily calcified occlusions with preserved caliber (56%), non-calcified occlusions with preserved caliber (19%), non-calcified occlusions with small caliber (15%) and heavily calcified occlusions with small caliber (10%).

CONCLUSIONS

SFA OCCLUSIONS ARE DISPARATE: this simple morphological study points out TASC II classification weaknesses for SFA occlusions, as quantitative cross-sectional imaging analysis with measurement of mean occluded diameter and percentage of calcifications can refine it. This could be particularly useful in the management of TASC II type D lesions, for which new endovascular revascularization techniques are arising, and where a CTA or MRA-based morphological classification could provide support in choosing between them.

KEYWORDS

Computer-assisted image processing; femoral artery; multidetector computed tomography; magnetic resonance angiography (MRA); peripheral arterial disease.