Evaluation of distal turbulence intensity for the detection of both plaque ulceration and stenosis grade in the carotid bifurcation using clinical Doppler ultrasound

Objectives

To determine the interrelationship of stenosis grade and ulceration with distal turbulence intensity (TI) in the carotid bifurcation measured using conventional clinical Doppler ultrasound (DUS) in vitro, in order to establish the feasibility of TI as a diagnostic parameter for plaque ulceration.

Methods

DUS TI was evaluated in a matched set of ulcerated and smooth-walled carotid bifurcation phantoms with various stenosis severities (30, 50, 60 and 70 %), where the ulcerated models incorporated a type 3 ulceration.

Results

Post-stenotic TI was significantly elevated owing to ulceration in the mild and moderate stenoses (P?<?0.001). TI increased with stenosis severity in both the ulcerated and non-ulcerated series, with a statistically significant effect of increasing stenosis severity (P?<?0.001). Whereas TI in the mild and non-ulcerated moderate stenoses was less than 20.4?±?1.3 cm s^?1, TI in the ulcerated moderate and severe models was higher than 25.6 ±1.3 cm s^?1, indicating a potential diagnostic threshold.

Conclusion

We report a two-curve relationship of stenosis grade and ulceration to distal TI measured using clinical DUS in vitro. Clinical DUS measurement of distal TI may be a diagnostic approach to detecting ulceration in the mild and moderately stenosed carotid artery.

Key Points

? Patients with carotid artery plaque ulcerations are at higher risk of stroke. ? Clinical Doppler ultrasound is routinely used to detect carotid artery stenosis. ? Doppler ultrasound turbulence intensity can detect ulceration in realistic flow models. ? Turbulence intensity also increases with stenosis severity independent of ulceration. ? Doppler ultrasound should help in assessing both stenosis severity and ulceration.     

Treatment of isolated chondral and osteochondral defects in the knee by autologous matrix-induced chondrogenesis (AMIC)

Purpose

The purpose of this study is to evaluate clinical and radiological outcomes of patients treated with autologous matrix-induced chondrogenesis (AMIC) for full-thickness chondral and osteochondral defects of the femoral condyles and patella.

Method

A retrospective evaluation of clinical and radiographic outcomes of patients treated with AMIC for chondral and osteochondral full-thickness cartilage defects of the knee was performed with a mean follow-up of 28.8 ± 1.5 months (range, 13–51 months).

Results

Significant improvements in clinical outcome scores (IKDC, Lysholm, Tegner, and VAS pain score) were noted. The largest improvements were seen in the osteochondral subgroup (mean age 25.9 years), whereas patients treated for chondral defects in the patellofemoral joint and on the femoral condyles improved less. Patients in all groups were generally satisfied with their results. MRI evaluation showed that tissue filling was present but generally not complete or homogenous.

Conclusions

AMIC is a safe procedure and leads to clinical improvement of symptomatic full-thickness chondral and osteochondral defects and to regenerative defect filling. The value of AMIC relative to other cartilage repair procedures and to the natural course remains undefined.

Level of evidence

Case series, Level IV.     

The normal internal carotid artery: a computed tomography angiographic study

Introduction

Systematic computed tomography angiographic (CTA) studies investigating variation in internal carotid artery (ICA) luminal diameters (LDs) are scarce. Knowledge of the normal intra-individual LD variability would provide a cut-off value for detection of more subtle collapses. In addition, low intra-individual variability would allow using contralateral LD as a reference for estimation of stenosis degree in cases where ipsilateral measurement is hampered. Therefore, our aim was to investigate intra-individual LD variation of normal ICA.

Methods

We retrospectively collected multidetector high-speed CTAs of 104 patients younger than 40 years who were considered not to have carotid pathology. We carried out independent measurements of the common carotid artery (CCA) and ICA LDs bilaterally from axial source images by two observers, analysing side-to-side LD differences from averaged double measurements with a paired t test.

Results

We discovered no significant side-to-side LD differences. In the female group, the mean differences (mm) with 95 % confidence intervals were 0.08 (0.00, 0.17) for CCA and 0.03 (?0.04, 0.11) for ICA, with ICA LD standard deviation of 0.4 mm. In the male group, these were: 0.06 (?0.04, 0.17), 0.02 (-0.07, 0.11) and 0.4 mm, respectively. We detected no ICA agenesis.

Conclusion

The intrinsic intra-individual variation of the LD of normal ICA is minimal. This uniformity may serve as the basis for detection of subtle grades of side-to-side variation caused by pathology.     

The effects of defect size, orientation, and location on subchondral bone contact in oval-shaped experimental articular cartilage defects in a bovine knee model

Purpose

Chondral defects of the knee may lead to pain and disability, often requiring surgical intervention. The purpose of this study was to identify how size, location, and orientation influences subchondral bone contact within oval-shaped chondral defects.

Methods

Full-thickness defects were created in twelve bovine knees. Defect orientation was randomized between coronal and sagittal planes on both the medial and lateral femoral condyles (MFC and LFC). In extension, knees were statically loaded to 1,000 N. Area measurements were recorded using Tekscan sensors and I-Scan software. A MATLAB program computed defect area and the area within the defect demonstrating subchondral bone contact.

Results

Defect area, location, and orientation each had a significant effect on subchondral bone contact (p < 0.001), and significant interactions were found between defect area and both location and orientation. The size threshold (cm²) at which significant contact occurred on the subchondral bone within the defect was smallest for LFC/coronal defects (0.73 cm²), then LFC/sagittal (1.14 cm²), then MFC/coronal (1.61 cm²), and then MFC/sagittal (no threshold reached).

Conclusions

Intra-articular location and orientation of a femoral condyle chondral defect, in addition to area, significantly influence femoral subchondral bone contact within the defect and the threshold at which subchondral bone contact occurs within the defect. The parameters of defect location and shape orientation supplement current surgical algorithms to manage knee articular cartilage surgery. This may indicate different cartilage restorative procedures based on the effect on the subchondral bone from the defect geometry itself and the selected cartilage surgery.     

320-row CT coronary angiography predicts freedom from revascularisation and acts as a gatekeeper to defer invasive angiography in stable coronary artery disease: a fractional flow reserve-correlated study

Objectives

To determine the accuracy of 320-row multidetector coronary computed tomography angiography (M320-CCTA) to detect functional stenoses using fractional flow reserve (FFR) as the reference standard and to predict revascularisation in stable coronary artery disease.

Methods

One hundred and fifteen patients (230 vessels) underwent M320-CCTA and FFR assessment and were followed for 18 months. Diameter stenosis on invasive angiography (ICA) and M320-CCTA were assessed by consensus by two observers and significant stenosis was defined as ≥50 %. FFR ≤0.8 indicated functionally significant stenoses.

Results

M320-CCTA had 94 % sensitivity and 94 % negative predictive value (NPV) for FFR ≤0.8. Overall accuracy was 70 %, specificity 54 % and positive predictive value 65 %. On receiver operating characteristic (ROC) curve analysis, the area under the curve (AUC) for CCTA to predict FFR ≤0.8 was 0.74 which was comparable with ICA. The absence of a significant stenosis on M320-CCTA was associated with a 6 % revascularisation rate. M320-CCTA predicted revascularisation with an AUC of 0.71 which was comparable with ICA.

Conclusions

M320-CCTA has excellent sensitivity and NPV for functional stenoses and therefore may act as an effective gatekeeper to defer ICA and revascularisation. Like ICA, M320-CCTA lacks specificity for functional stenoses and only has moderate accuracy to predict the need for revascularisation.

Key Points

? Important information about the heart is provided by 320-row multidetector CT coronary angiography (M320-CCTA). ? M320-CCTA accurately detects and excludes functional stenoses determined by fractional flow reserve (FFR). ? Non-significant stenoses on M320-CCTA associated with fewer cardiac events and less revascularisation. ? M320-CCTA may act as a gatekeeper for invasive angiography and inappropriate revascularisation. ? Like ICA, M320-CCTA only has moderate accuracy to predict vessels requiring revascularisation.     

Intracranial carotid artery disease in patients with recent neurological symptoms: high prevalence on CTA

Introduction

Novel postprocessing techniques have enabled accurate quantification of intracranial carotid atherosclerotic disease on CT Angiography (CTA). Our purpose was to estimate the prevalence of intracranial carotid artery disease, i.e., stenosis and calcium, on CTA in patients with recent neurological symptoms.

Methods

The degree of stenosis and calcium volume of 162 extracranial and intracranial internal carotid arteries (ICAs) was quantitatively measured on CTA images of 88 consecutive patients with recent neurological symptoms and extracranial ICA stenosis as screened by ultrasound. The prevalence of intracranial ICA stenosis and presence of calcium was estimated and correlated with extracranial ICA stenosis.

Results

Intracranial ICA stenosis was observed in 83 % (95 %CI: 77–89 %) and 39 % (95 %CI: 31–47 %) for a stenosis of ≥30 % and ≥50 %, respectively. Only on the symptomatic side, a statistical significant correlation between intracranial and extracranial stenoses was observed (Pearson's r 0.32, P?=?0.006). In the 37 arteries with an extracranial ICA stenosis of ≥70 %, 89 % (95 %CI: 79–99 %) and 46 % (95 %CI: 30–62 %) of the intracranial ICA showed a stenosis of ≥30 % and ≥50 %, respectively.

Conclusion

In our population of patients with recent neurological symptoms and extracranial stenosis as screened by ultrasound, CTA imaging resulted in a substantially higher prevalence of intracranial ICA disease than previously reported. This remarkably high prevalence of intracranial ICA disease on CTA may have important future implications for acute and preventive treatment strategies.     

Comprehensive assessment of spotty calcifications on computed tomography angiography: Comparison to plaque characteristics on intravascular ultrasound with radiofrequency backscatter analysis

Background

The purpose of the study was to systematically compare calcification patterns in plaques on computed tomography angiography (CTA) with plaque characteristics on intravascular ultrasound with radiofrequency backscatter analysis (IVUS-VH).

Methods and Results

In total, 108 patients underwent CTA and IVUS-VH. On CTA, calcification patterns in plaques were classified as non-calcified, spotty or dense calcifications. Plaques with spotty calcifications were differentiated into small spotty (<1 mm), intermediate spotty (1-3 mm) and large spotty calcifications (≥3 mm). Plaque characteristics deemed more high-risk on IVUS-VH were defined by % necrotic core (NC) and presence of thin cap fibroatheroma (TCFA). Overall, 300 plaques were identified both on CTA and IVUS-VH. % NC core was significantly higher in plaques with small spotty calcifications as compared to non-calcified plaques (20% vs 13%, P = .006). In addition, there was a trend for a higher % NC in plaques with small spotty calcifications than in plaques with intermediate spotty calcifications (20% vs 14%, P = .053). Plaques with small spotty calcifications had the highest % TCFA as compared to large spotty and dense calcifications (31% vs 9% and 31% vs 6%, P < .05).

Conclusion

Plaques with small spotty calcifications on CTA were related to plaque characteristics deemed more high-risk on IVUS-VH. Therefore, CTA may be valuable in the assessment of the vulnerable plaque.     

Perfusion differences on SPECT and PWI in patients with acute ischemic stroke

Introduction

The purposes of the present study were to compare the flow defect volumes on perfusion-weighted magnetic resonance imaging (PWI) and ^99mTc-labeled ethylcysteinate dimer (^99mTc-ECD) single photon emission computed tomography (SPECT) at acute and subacute stages of ischemic stroke and to analyze the relationship between the detected flow defects on the two methods and neurological status and clinical outcomes.

Methods

Perfusion defects on PWI and SPECT were measured within 48 h and on day 8 of the onset of stroke from 22 patients with their first-ever acute supratentorial ischemic stroke. The primary neurological status was evaluated prior to the imaging. Clinical outcome was assessed at 3 months after the onset of the stroke.

Results

The volumes of cerebral blood flow (CBF) defects did not differ between SPECT and PWI within the 48-h examinations. However, the volume of CBF defect was significantly larger on SPECT than on PWI on day 8 (p = 0.03). Within the 48-h examinations, the CBF defect volumes on SPECT and PWI were comparably related to the neurological status. On day 8, the CBF defect volume on SPECT showed higher correlation to the neurological status and more precisely predicted the clinical outcomes at 3 months than PWI.

Conclusions

^99mTC-ECD-SPECT and PWI both have ability to detect cerebral hypoperfusion in patients with ischemic stroke but with some differences. The value of SPECT is more accurate in terms of the delayed outcome, such as prognosis and rehabilitation planning.     

Cartilage repair using mesenchymal stem cell (MSC) sheet and MSCs-loaded bilayer PLGA scaffold in a rabbit model

Purpose

The integration of regenerated cartilage with surrounding native cartilage is a major challenge for the success of cartilage tissue-engineering strategies. The purpose of this study is to investigate whether incorporation of the power of mesenchymal stem cell (MSC) sheet to MSCs-loaded bilayer poly-(lactic-co-glycolic acid) (PLGA) scaffolds can improve the integration and repair of cartilage defects in a rabbit model.

Methods

Rabbit bone marrow-derived MSCs were cultured and formed cell sheet. Full-thickness cylindrical osteochondral defects (4 mm in diameter, 3 mm in depth) were created in the patellar groove of 18 New Zealand white rabbits and the osteochondral defects were treated with PLGA scaffold (n = 6), PLGA/MSCs (n = 6) or MSC sheet-encapsulated PLGA/MSCs (n = 6). After 6 and 12 weeks, the integration and tissue response were evaluated histologically.

Results

The MSC sheet-encapsulated PLGA/MCSs group showed significantly more amounts of hyaline cartilage and higher histological scores than PLGA/MSCs group and PLGA group (P < 0.05). In addition, the MSC sheet-encapsulated PLGA/MCSs group showed the best integration between the repaired cartilage and surrounding normal cartilage and subchondral bone compared to other two groups.

Conclusions

The novel method of incorporation of MSC sheet to PLGA/MCSs could enhance the ability of cartilage regeneration and integration between repair cartilage and the surrounding cartilage. Transplantation of autologous MSC sheet combined with traditional strategies or cartilage debris might provide therapeutic opportunities for improving cartilage regeneration and integration in humans.     

Quantification and characterisation of coronary artery plaque volume and adverse plaque features by coronary computed tomographic angiography: a direct comparison to intravascular ultrasound

Objective

We evaluated the performance of manual measures of coronary plaque volumes and atherosclerotic plaque features from coronary CT angiography (CTA), using intravascular ultrasound (IVUS) as the reference.

Methods

Thirty individual coronary plaques with suitable fiduciary markers were identified. Plaque volumes on coronary CTA were manually quantified by two observers and compared to IVUS plaque volumes as interpreted by an independent laboratory. The presence of adverse plaque characteristics—low attenuation plaque (LAP), positive remodelling (PR) and spotty calcification (SC)—on coronary CTA was evaluated and compared to IVUS.

Results

High correlation in plaque volumes was detected between observers (r?=?0.94, P?<?0.0001; 95 % limits of agreement <48.7 mm³, bias 6.6 mm³). Excellent correlation (r?=?0.95, P?<?0.0001) was noted in plaque volume between independent observers and IVUS (95 % limits of agreement <40.6 mm³, bias ?4.4 mm³) and did not differ from IVUS (105.0?±?56.7 vs. 109.4?±?60.7 mm³, P?=?0.2). The frequency of LAP (10 % vs. 17 %), PR (7 % vs. 10 %) and SC (27 % vs. 33 %) was similar between coronary CTA and IVUS (all P?=?NS).

Conclusions

Plaque volume on coronary CTA determined by manual methods demonstrates high correlation and modest agreement to IVUS. Further, coronary CTA demonstrates high accuracy for the identification of adverse plaque characteristics, including LAP, PR and SC.

Key Points

? Coronary CT angiography is a non-invasive test that enables coronary plaque assessment ? Plaque quantification by coronary CT angiography correlates well with intravascular ultrasound findings ? Coronary CT angiography can identify adverse plaque characteristics     

Xenotransplantation of human mesenchymal stem cells for repair of osteochondral defects in rabbits using osteochondral biphasic composite constructs

Purpose

The aim of this work is to investigate the feasibility of non-autologous transplantation of human mesenchymal stem cells (hMSCs) with or without differentiation for the regeneration of osteochondral defects in rabbits using a biphasic composite construct composed of platelet-rich fibrin glue (PR-FG) and hydroxyapatite.

Methods

After isolation and culture, hMSCs were seeded on biphasic composite constructs (hydroxyapatite + PR-FG) and transplanted into osteochondral defects of adult New Zealand white rabbits. Treatment of individual defects was applied by random assignment to one of five groups: (1) control, defects untreated; (2) hydroxyapatite, defects filled with hydroxyapatite only; (3) hydroxyapatite + PR-FG, defects filled with a composite of hydroxyapatite and PR-FG; (4) hydroxyapatite + PR-FG + undifferentiated hMSCs; and (5) hydroxyapatite + PR-FG + differentiated hMSCs. Rabbits were killed at 4 or 8 weeks post-surgery, at which time osteochondral repair was macroscopically and histologically evaluated and scored using the modified International Cartilage Repair Society scoring system.

Results

The group in which defects were seeded with differentiated hMSCs (group 5) showed superior healing of osteochondral defects based on macroscopic and histological observations compared to other groups. Specifically, 8 weeks after implantation, defects were filled with more hyaline-like cartilage and were better integrated with the surrounding native cartilage. The histological scores were significantly better than those of other groups (16.3 at 8 weeks, p < 0.01).

Conclusion

Xenogeneic transplantation of differentiated hMSCs using a biphasic composite construct effectively repaired osteochondral defect in a rabbit model. Differentiated hMSCs showed superior healing of chondral lesion to undifferentiated hMSCs.     

Interscan reproducibility of quantitative coronary plaque volume and composition from CT coronary angiography using an automated method

Objectives

Quantitative measurements of coronary plaque volume may play a role in serial studies to determine disease progression or regression. Our aim was to evaluate the interscan reproducibility of quantitative measurements of coronary plaque volumes using a standardized automated method.

Methods

Coronary dual source computed tomography angiography (CTA) was performed twice in 20 consecutive patients with known coronary artery disease within a maximum time difference of 100 days. The total plaque volume (TP), the volume of non-calcified plaque (NCP) and calcified plaque (CP) as well as the maximal remodelling index (RI) were determined using automated software.

Results

Mean TP volume was 382.3?±?236.9 mm³ for the first and 399.0?±?247.3 mm³ for the second examination (p?=?0.47). There were also no significant differences for NCP volumes, CP volumes or RI. Interscan correlation of the plaque volumes was very good (Pearson’s correlation coefficients: r?=?0.92, r?=?0.90 and r?=?0.96 for TP, NCP and CP volumes, respectively).

Conclusions

Automated software is a time-saving method that allows accurate assessment of coronary atherosclerotic plaque volumes in coronary CTA with high reproducibility. With this approach, serial studies appear to be possible.

Key Points

? Reproducibility of coronary atherosclerotic plaque volume in coronary CTA is high. ? Using automated software facilitates quantitative measurements. ? Serial studies to determine progression or regression of coronary plaque are possible.     

Infundibular dilation and aneurysm at the origin of the posterior communicating artery: differential diagnosis by CT angiography

Introduction

Infundibular dilation (ID) and aneurysm at the internal carotid artery (ICA)–posterior communicating artery (PComA) junction can be difficult to distinguish but may differ in clinical significance. The aim of this study was to evaluate the utility of CT angiography (CTA) in differentially diagnosing IDs and small unruptured aneurysms at the ICA–PComA junction.

Methods

This retrospective study comprised 88 patients diagnosed with 107 protrusions (70 IDs and 37 aneurysms <5 mm; 19 bilateral lesions) at the ICA–PComA junction who underwent both CTA and digital subtraction angiography (DSA). Two neuroradiologists independently reviewed CTA and DSA images according to these criteria: (a) size (maximum dimension <3 or ≥3 mm), (b) shape (triangular or round/oval/irregular), (c) aneurysmal neck (absent or present), (d) horizontal direction (posteriomedial or posteriolateral), and (e) PComA origin (apex, no PComA, or base). The intermodality (between CTA and DSA) and interobserver (between the two readers) agreement were determined for each finding. We also evaluated the sensitivity and specificity of CTA for distinguishing ID and aneurysm, using DSA as the reference standard.

Results

The mean κ values of intermodality agreement for the size, shape, aneurysmal neck, horizontal direction, and PComA origin were 0.88, 0.87, 0.84, 0.71, and 0.56, respectively. All interobserver agreements of CTA and DSA were excellent. The sensitivity, specificity, and accuracy of CTA for differentiating aneurysms from IDs were 94.6, 100, and 98.0 %, respectively.

Conclusion

CTA may be a useful noninvasive modality for differential diagnosis of ID and aneurysm at the ICA–PComA junction.     

Single-source dual-energy CT angiography with reduced iodine load in patients referred for aortoiliofemoral evaluation before transcatheter aortic valve implantation: impact on image quality and radiation dose

Objectives

To compare image quality and radiation dose of pre-transcatheter aortic valve implantation (TAVI) aortoiliofemoral CT angiography (AICTA) provided by standard vs. dual-energy mode with reduced iodine load protocols.

Methods

One hundred and sixty-one patients underwent a two-step CTA protocol before TAVI including cardiac CTA with injection of 65 mL of iodinated contrast agent (ICA), immediately followed by AICTA. From this second acquisition, the following three different patient groups were identified: Group 1: 52 patients with standard AICTA (60 mL ICA, 100 kVp, mA automodulation); Group 2: 48 patients with dual-energy AICTA with 50 % iodine load reduction (30 mL ICA, fast kVp switching, 600 mA); Group 3: 61 patients with an identical protocol to Group 2, but exposed to 375 mA. The qualitative/subjective image quality (13-point score) and quantitative/objective image quality (contrast attenuation and image noise) were evaluated. The radiation dose was recorded.

Results

There was no significant difference in non-diagnostic images between the three protocols. Contrast attenuation, signal-to-noise ratio and contrast-to-noise ratio were significantly higher, whereas noise was significantly lower in the standard protocol (all P?P?Conclusions Dual-energy AICTA before TAVI results in a reduction of iodine load while maintaining sufficient diagnostic information despite increased noise.

Key Points

? Dual-energy AICTA before TAVI results in a 50 % reduction of iodine load. ?The reduction of iodine load maintains sufficient image quality despite increased noise. ? Using 375 mA in dual-energy mode results in a reduction of radiation dose. ? A high tube current setting (600 mA) should be used in overweight patients.     

Dual-energy computed tomography after endovascular aortic aneurysm repair: The role of hard plaque imaging for endoleak detection

Objectives

To assess the diagnostic accuracy of dual-energy computed tomography (DECT) for detection of endoleaks and aneurysm sac calcifications after endovascular aneurysm repair (EVAR) using hard plaque imaging algorithms.

Materials and methods

One hundred five patients received 108 triple-phase contrast-enhanced CT (non-contrast, arterial and delayed phase) after EVAR. The delayed phase was acquired in dual-energy and post-processed using the standard (HPI-S) and a modified (HPI-M) hard plaque imaging algorithm. The reference standard was determined using the triple-phase CT and contrast-enhanced ultrasound. All images were analysed separately for the presence of endoleaks and calcifications by two independent readers; sensitivity, specificity and interobserver agreement were calculated.

Results

Endoleaks and calcifications were present in 25.9 % (28/108) and 20.4 % (22/108) of images. The HPI-S images had a sensitivity/specificity of 54 %/100 % (reader 1) and 57 %/99 % (reader 2), the HPI-M images of 93 %/92 % (reader 1) and 96 %/92 % (reader 2) for detection of endoleaks. For detection of calcifications HPI-S had a sensitivity/specificity of 91 %/99 % (reader 1) and 95 %/97 % (reader 2), the HPI-M images of 91 %/99 % (reader 1) and 91 %/99 % (reader 2), respectively.

Conclusion

Using HPI-M, DECT enables an accurate diagnosis of endoleaks after EVAR and allows distinguishing between endoleaks and calcifications with high diagnostic accuracy.

Key Points

? Dual-energy computed tomography allows the diagnosis of aortic pathologies after EVAR. ? Hard plaque imaging algorithms can distinguish between endoleaks and aneurysm sac calcifications. ? The modified hard plaque imaging algorithm detects endoleaks with high diagnostic accuracy.     

Motion frozen 18F-FDG cardiac PET

Background

PET reconstruction incorporating spatially variant 3D Point Spread Function (PSF) improves contrast and image resolution. “Cardiac Motion Frozen” (CMF) processing eliminates the influence of cardiac motion in static summed images. We have evaluated the combined use of CMF- and PSF-based reconstruction for high-resolution cardiac PET.

Methods

Static and 16-bin ECG-gated images of 20 patients referred for ¹⁸F-FDG myocardial viability scans were obtained on a Siemens Biograph-64. CMF was applied to the gated images reconstructed with PSF. Myocardium to blood contrast, maximum left ventricle (LV) counts to defect contrast, contrast-to-noise (CNR) and wall thickness with standard reconstruction (2D-AWOSEM), PSF, ED-gated PSF, and CMF-PSF were compared.

Results

The measured wall thickness was 18.9 ± 5.2 mm for 2D-AWOSEM, 16.6 ± 4.5 mm for PSF, and 13.8 ± 3.9 mm for CMF-PSF reconstructed images (all P < .05). The CMF-PSF myocardium to blood and maximum LV counts to defect contrasts (5.7 ± 2.7, 10.0 ± 5.7) were higher than for 2D-AWOSEM (3.5 ± 1.4, 6.5 ± 3.1) and for PSF (3.9 ± 1.7, 7.7 ± 3.7) (CMF vs all other, P < .05). The CNR for CMF-PSF (26.3 ± 17.5) was comparable to PSF (29.1 ± 18.3), but higher than for ED-gated dataset (13.7 ± 8.8, P < .05).

Conclusion

Combined CMF-PSF reconstruction increased myocardium to blood contrast, maximum LV counts to defect contrast and maintained equivalent noise when compared to static summed 2D-AWOSEM and PSF reconstruction.     

Restriction of the referral of patients with stable angina for CT coronary angiography by clinical evaluation and calcium score: impact on clinical decision making

Objective

To investigate the value of the calcium score (CaSc) plus clinical evaluation to restrict referral for CT coronary angiography (CTCA) by reducing the number of patients with an intermediate probability of coronary artery disease (CAD).

Methods

We retrospectively included 1,975 symptomatic stable patients who underwent clinical evaluation and CaSc calculation and CTCA or invasive coronary coronary angiography (ICA). The outcome was obstructive CAD (≥50 % diameter narrowing) assessed by ICA or CTCA in the absence of ICA. We investigated two models: (1) clinical evaluation consisting of chest pain typicality, gender, age, risk factors and ECG and (2) clinical evaluation with CaSc. Discrimination of the two models was compared. The stepwise reclassification of patients with an intermediate probability of CAD (10–90 %) after clinical evaluation followed by clinical evaluation with CaSc was assessed by clinical net reclassification improvement (NRI).

Results

Discrimination of CAD was significantly improved by adding CaSc to the clinical evaluation (AUC: 0.80 vs. 0.89, P?<?0.001). CaSc and CTCA could be avoided in 9 % using model 1 and an additional 29 % of CTCAs could be avoided using model 2. Clinical NRI was 57 %.

Conclusion

CaSc plus clinical evaluation may be useful in restricting further referral for CTCA by 38 % in symptomatic stable patients with suspected CAD.

Key Points

? CT calcium scores (CaSc) could proiritise referrals for CT coronary angiography (CTCA) ? CaSc provides an incremental discriminatory value of CAD compared with clinical evaluation ? Risk stratification is better when clinical evaluation is combined with CaSc ? Appropriate use of clinical evaluation and CaSc helps avoid unnecessary CTCA referrals     

Uptake of F-18 FDG and ultrasound analysis of carotid plaque

Objectives

To elucidate the relation between the echolucent plaque on carotid ultrasound and acute inflammation on F-18 FDG carotid PET/CT.

Methods

Thirty nine patients (M:F ratio = 23:16, mean age = 63 ± 11 years) that underwent coronary angiography and carotid ultrasound were divided into three groups—echolucent plaque (n = 22), calcified (n = 10), and no plaque(n = 7). All the patients underwent F-18 FDG carotid PET/CT. The mean standardized uptake values (SUV), namely target to background ratio (TBR) on 180 minutes delayed F-18 FDG carotid PET/CT images were compared with levels of serum inflammatory markers and lipid profiles, and in terms of the presence of carotid plaque on carotid US.

Results

180 minutes TBR of carotid arterial wall at echolucent plaque, calcified plaque, and no plaque were 1.40 ± 0.05, 1.23 ± 0.03, 1.17 ± 0.03 in both carotid artery. TBR of carotid arterial walls for echolucent plaque were significantly larger than TBR for calcified, and no plaque respectively at the both side of carotid artery (P < .05). Serum HDL levels were found to be inversely correlated with F-18 FDG uptake at both carotid arteries (r = ?0.43, P = .005) on 180 minutes delayed phase images. Also serum hs-CRP levels were found to be correlated with F-18 FDG TBR values of right carotid arteries (r = 0.41, P = .04).

Conclusions

Our results show that F-18 FDG carotid PET/CT can depict metabolically active atherosclerotic plaques, and suggest that F-18 FDG carotid PET/CT can be used as a noninvasive imaging modality for functional evaluation of atherosclerosis.     

Wall shear stress distribution at the carotid bifurcation: influence of eversion carotid endarterectomy

Objectives

To test the feasibility of four-dimensional (4D) flow MRI to quantify the systolic wall shear stress (WSS_systole) and oscillatory shear index (OSI) in high-grade internal carotid artery (ICA) stenosis before and after endarterectomy (CEA).

Methods

Twenty patients with ≥60 % ICA stenosis were prospectively and consequently included. Four-dimensional flow MRI was used to measure individual time-resolved 3D blood flow velocities. Segmental WSS_systole and OSI were derived at eight wall segments in analysis planes positioned along the ICA, common (CCA) and external carotid artery (ECA).

Results

Regional WSS_systole of all patients decreased after CEA (P?<?0.05). Changes were most prominent at the ICA bulb but remained unchanged in the CCA and ECA. OSI was significantly lower after CEA in the lateral vessel walls (P?<?0.05). For analysis planes at the stenosis in- and outlet, a reduction of mean WSS_systole by 32 % and 52 % (P?<?0.001) and OSI distal to the stenosis (40 %, P?=?0.01) was found after CEA.

Conclusions

Our findings show the potential of in vivo 4D flow MRI to quantify haemodynamic changes in wall shear stress even in patients with complex flow conditions.

Key Points

? The 4D flow MRI allows in vivo measurement of individual 3D blood flow. ? Regional wall shear stress can be derived from such 3D flow data. ? Even complex flow in high-grade internal carotid artery stenosis can be analysed. ? This technique could be valuable for future studies of carotid atherosclerosis.     

Microfracture combined with osteochondral paste implantation was more effective than microfracture alone for full-thickness cartilage repair

Purpose

The aim of this study was to evaluate whether the microfracture combined with osteochondral paste implantation could promote the quality of the regenerated tissue in the knee joints of rabbits.

Methods

Sixty-six New Zealand white rabbits were used. Bilateral knee joints from the same rabbit were randomly divided into experimental group and microfracture group. An articular cartilage defect was established in the femoral trochlear groove. In the experimental group, the defect was microfractured and covered with osteochondral paste harvested from the intercondylar notch. The regenerated tissues were harvested for gross morphology, histology, biochemistry and gene expression analysis at 4, 8 and 12 weeks postoperatively.

Results

The regenerated tissue had a slowly mature process in both groups. At 12 weeks, the regenerated tissue in the experimental group appeared much more thicker and white with higher percentages of defect filling macroscopically. In histology, the experimental group found a majority of hyaline-like regenerate tissue with intense Safranin-O and collagen type II staining, while fibrocartilage-like tissue was mostly seen in the microfracture group with poor Safranin-O and collagen type II staining. The experimental group had higher Wakitani scores and narrower acellular zones than those in the microfracture group (P < 0.05). For biochemical analysis, both the GAG content and the DNA-normalized GAG content saw a time-dependent increase with a much higher value found in the experimental group at 8 and 12 weeks (P < 0.05). On the contrary, the total DNA content decreased with time in both groups, and the difference between the two groups was only found at 4 and 8 weeks (P < 0.05). For gene expression analysis, the experimental group had much higher expression levels than the microfracture group as for collagen type II and aggrecan, but not for collagen type I.

Conclusion

Microfracture combined with paste implantation can result in improved quality of the reparative tissue and may have a positive effect on the integration to the surrounding cartilage in the rabbit model. The technique offers a promising treatment option for cartilage defects and improves the regeneration of articular cartilage for patients with painful chondral lesions.