Association between carotid plaque enhancement shown by multidetector CT angiography and histologically validated microvessel density

Purpose

Carotid plaques analysed by MDCTA can show contrast enhancement. The purpose of this study was to explore the association between carotid plaque enhancement (CPE) and microvessel density.

Materials and methods

We obtained IRB approval. Twenty-nine consecutive (male, 20; median age, 63) symptomatic patients studied with 16-detector CT were prospectively analysed. Examinations were performed before and after intravenous contrast medium administration, and analysis of plaque enhancement was performed. Patients underwent “en bloc” carotid endarterectomy; histological sections were prepared and the presence of microvessels quantified. Logistic regression analysis as well as ROC curve and area under the curve was calculated.

Results

A statistically significant association between the degree of CPE and microvessel density (P?=?0.009; rho?=?0.553) was observed. The ROC curve analysis confirmed this association with an area under the curve of 0.906, 0.735, 0.644 and 0.546 for CPE of 10 HU, 15 HU, 20 HU and 25 HU respectively. There was a statistically significant difference between the CPE and the degree of neovascularisation (P?=?0.0003).

Conclusion

Results of this preliminary study suggest that CPE might be associated with the microvessel density. Histological analysis seems to demonstrate that the degree of intra-plaque neo-vascularisation is statistically associated with CPE.

Key Points

• Carotid artery plaque enhancement at CT is associated with microvessel density.
• The degree of intra-plaque neo-vascularisation is statistically associated with carotid plaque enhancement.
• Plaque enhancement at CT should be considered when assessing vulnerable plaques.

     

Protection from natural infection after live influenza virus immunization in an open population.

Live attenuated influenza vaccine containing the recombinant of A/Victoria/3/75 with A/PR/8/34 virus was administered to healthy adults in a field trial aimed at evaluating protection provided by immunization. The study was designed to measure the effect of vaccination on absenteeism from respiratory disease during a natural influenza epidemic. A total of 2115 male employees of the public transport service of Rome volunteered to participate in the trial, 1050 and 1065 receiving vaccine and placebo respectively, in a randomized blind fashion. Vaccination procedure was completed by the end of December 1976. A small-sized outbreak of influenza, due to a viral strain antigenically homologous to the vaccine, occurred during the month of February 1977. Analysis of absenteeism data, classified according to medical certificate, indicated that morbidity from respiratory disease was reduced in vaccinees compared with controls during the epidemic month; the rate of increase of morbidity compared with that of the preceding month was then three times lower in vaccinees than in controls and the difference in absenteeism between the two groups greatly exceeded the ordinary fluctuation that was observed during non-epidemic periods.     

Purging iron from the heart

Methods are now available to measure the magnitude of iron accumulation in the heart. Their validation currently relies on indirect evidence and not on chemical estimation in cardiac biopsies. All patients with symptomatic heart disease appear to have abnormal T2* values, but many patients without symptomatic heart disease also have evidence of increased myocardial iron. Although there is no proof to date that increased myocardial iron, as evidenced by abnormal magnetic resonance imaging, carries an adverse prognosis, it is likely that such new information will affect the chelating programme of patients. In these cases, there are a number of options available: (i) ongoing treatment with either desferrioxamine (DFO) or deferiprone may be intensified; (ii) the patient may be switched to the alternative chelator or (iii) combined chelation with both DFO and deferiprone may be started, which is more effective than using either chelator alone. For patients with symptomatic heart disease, continuous intravenous DFO with, or without deferiprone, remains the currently recommended treatment, in view of its documented ability to salvage these patients.     

Current smoking predicts inadequate response to methotrexate monotherapy in rheumatoid arthritis patients naïve to DMARDs: Results from a retrospective cohort study

Identifying predictors of inadequate response to methotrexate (MTX) in rheumatoid arthritis (RA) is key to move from a “trial and error” to a “personalized medicine” treatment approach where patients less likely to adequately respond to MTX monotherapy could start combination therapy at an earlier stage. This study aimed to identify potential predictors of inadequate response to MTX in RA patients naïve to disease modifying anti-rheumatic drugs.Data from a real-life cohort of newly diagnosed RA patients starting MTX (baseline, T0) as first-line therapy were analyzed. Outcomes, assessed after 6 months (T1), were defined as failure to achieve a disease activity score 28 (DAS28) low disease activity (LDA) or a good/moderate response to MTX, according to the European League Against Rheumatism (EULAR) response criteria. Logistic regression was used to assess the associations between baseline variables and the study outcomes.Overall, 294 patients (60.5% females, median age 54.5 years) with a median disease duration of 7.9 months were recruited. At T1, 47.3% of subjects failed to achieve LDA, and 29.3% did not have any EULAR-response. In multivariate analysis, significant associations were observed between no LDA and current smoking (adjusted odds ratio [adjOR] 1.79, P = .037), female gender (adjOR 1.68, P = .048), and higher DAS28 (adjOR 1.31, P = .013); and between no EULAR-response and current smoking (adjOR: 2.04, P = .019), age (adjOR: 0.72 per 10-years increases, P = .001), and higher erythrocyte sedimentation rate (adjOR: 0.49; P = .020). By contrast, there were no associations between past smoker status and study outcomes.In summary, in our real-life cohort of disease modifying anti-rheumatic drug naïve RA patients, current smoking habit independently predicts inadequate response to MTX. This, together with other independent predictors of response to treatment identified in our study, might assist with personalized monitoring in RA patients. Further studies are required to investigate whether smoking quitting strategies enhance the therapeutic response to MTX.     

Diagnosis of hepatic hemangioma with simplified double 99mTc labelling

The authors report on their experience with liver hemangioma (LH) diagnosis by means of a simplified method--that is, the simultaneous, in vivo, double labelling of liver reticuloendothelial system (RES) and of red blood cells (RBC) by 99mTc. Twenty-eight patients with US diagnosis of suspected LH and 15 controls were examined after sequential iv injection of SnCl2, of 99mTc-mucolloid albumin and, after liver scintigraphy, of 99mTc-pertechnetate to conclude in vivo RBC labelling. All patients underwent CT and, if necessary, CT-guided biopsy. Focal colloid defects filled after RBC labelling were shown in 20/22 patients with unquestionable LH. No colloid defects were shown in 6/28 cases (expansive process). 15/15 controls showed unchanged non-filling defects after double labelling. Finally, the authors point out that, in the diagnosis of LH, sequential double labelling of liver RES and RBC appears to be a quicker scintigraphic technique than conventional ones. Moreover, this technique has the same high specificity and sensitivity as more time-consuming ones.     

Correlation between Fissured Fibrous Cap and Contrast Enhancement: Preliminary Results with the Use of CTA and Histologic Validation

BACKGROUND AND PURPOSE:Previous studies demonstrated that carotid plaques analyzed by CTA can show contrast plaque enhancement. The purpose of this preliminary work was to evaluate the possible association between the fissured fibrous cap and contrast plaque enhancement.MATERIALS AND METHODS:Forty-seven consecutive (men = 25; average age = 66.8 ± 9 years) symptomatic patients studied by use of a multidetector row CT scanner were prospectively analyzed. CTA was performed before and after contrast and radiation doses were recorded; analysis of contrast plaque enhancement was performed. Patients underwent carotid endarterectomy en bloc; histologic sections were prepared and evaluated for fissured fibrous cap and microvessel attenuation. The Mann-Whitney test was performed to evaluate the differences between the 2 groups. A multiple logistic regression analysis was performed to assess the effect of fissured fibrous cap and microvessel attenuation on contrast plaque enhancement. Receiver operating characteristic curve and area under the curve were also calculated.RESULTS:Twelve patients had fissured fibrous cap. In 92% (11/12) of fissured fibrous cap–positive plaques, we found contrast plaque enhancement, whereas in 69% (24/35) of the plaques without fissured fibrous cap contrast plaque enhancement was found. The Mann-Whitney test showed a statistically significant difference between the contrast enhancement in plaques with fissured fibrous cap (Hounsfield units = 22.6) and without fissured fibrous cap (Hounsfield units = 12.9) (P = .011). On the regression analysis, both fissured fibrous cap and neovascularization were associated with contrast plaque enhancement (P = .0366 and P = .0001). The receiver operating characteristic curve confirmed an association between fissured fibrous cap and contrast plaque enhancement with an area under the curve of 0.749 (P = .005).CONCLUSIONS:The presence of fissured fibrous cap is associated with contrast plaque enhancement. Histologic analysis showed that the presence of fissured fibrous cap is associated with a larger contrast plaque enhancement compared with the contrast plaque enhancement of plaques without fissured fibrous cap.

The presence of fissured fibrous cap (FFC) in the carotid artery plaque is associated with an increased risk of cerebrovascular events, and therefore FFC is considered one element that makes a carotid plaque “vulnerable.”^1–3 Identification of this condition is important to obtain a better stratification of stroke risk.¹The FFC has been studied by use of MR imaging, demonstrating the potential of MR imaging to detect the rupture of the fibrous cap,^4,5 with or without the use of gadolinium.^6,7 Recently, with the use of CTA and morphologic analysis of the carotid plaque, the FFC was documented.⁸ Even though the rupture of FFC has been shown to be associated with enhancement on MR imaging,⁷ this association has not yet been demonstrated by use of CT. The carotid plaque enhancement (CPE) on CTA is associated with plaque instability^9–11; CPE is associated with microvessel attenuation, but the neovascularization alone cannot be the only factor because some plaques with high CPE do not show neovascularization.⁹Our hypothesis is that the rupture of the FFC is an independent factor related to the CPE, and we aim to evaluate this association.