Comparison of remnant size in embolized intracranial aneurysms measured at follow-up with DSA and MRA

Introduction

The possibility of recanalization and the need for retreatment are the most important limitations of intracranial aneurysm embolization. The purpose of the study was to compare the size of aneurysm remnants measured at follow-up with three-dimensional digital subtracted angiography (3D-DSA) and magnetic resonance angiography (MRA).

Methods

Twenty-six aneurysms were found incompletely occluded in 72 consecutively examined patients at a follow-up after 3?months. The diameters and volume of aneurysm remnants were compared between 3D-DSA, time-of-flight MRA (TOF-MRA), contrast-enhanced TOF-MRA (CE-TOF-MRA), and contrast-enhanced MRA (CE-MRA) at 1.5?T.

Results

There was a significant correlation between remnant volumes calculated based on 3D-DSA and all MRA modalities. The intraobserver variability of the measurements ranged from 3.4 to 4.1?% and the interobserver variability from 5.8 to 7.3?%. There were no significant differences in the variability between the techniques. The mean residual filling volume ranged from 16.3?±?19.0?mm³ in TOF-MRA to 30.5?±?44.6?mm³ in 3D-DSA (P?<?0.04). Significant differences were found in the volumes measured with 3D-DSA and CE-MRA as compared to TOF-MRA and CE-TOF-MRA (P?<?0.01). There was a moderate significant correlation between the residual filling and the relative error of measurement in the case of TOF-MRA and CE-TOF-MRA.

Conclusions

TOF-MRA seems to underestimate the size of aneurysm remnants detected at follow-up and should not be used as a sole imaging method to decide on re-embolization.     

Time-of-flight MR angiography at 3T versus digital subtraction angiography in the imaging follow-up of 51 intracranial aneurysms treated with coils

Objective

To compare 3D time-of-flight MR angiography (TOF-MRA) at 3 Tesla (3 T) with digital subtraction angiography (DSA) for the evaluation of intracranial aneurysm occlusion after endovascular coiling.

Methods

In a prospective study, 51 consecutive patients (25 females, 26 males; median age, 51 years) with 51 saccular aneurysms treated with endovascular coiling underwent simultaneous DSA and 3 T TOF-MRA at follow-up. DSA and TOF-MRA images were analyzed independently by two senior neuroradiologists. Findings were assigned to 1 of 3 categories in the Raymond classification: complete obliteration, residual neck or residual aneurysm. Agreement between observers and techniques was evaluated using κ statistics.

Results

DSA images were not interpretable for one patient. Interobserver agreement was determined as excellent for DSA (κ = 0.86) and TOF-MRA (κ = 0.80). After reaching a consensus, DSA follow-up showed 26 (51%) complete obliterations, 20 (39%) residual necks and 4 (8%) residual aneurysms. TOF-MRA showed 23 (45%) complete obliterations, 22 (43%) residual necks and 6 (12%) residual aneurysms. Comparison between TOF-MRA and DSA showed excellent agreement between the techniques (κ = 0.86). In the four cases that were misclassified, TOF-MRA findings were assigned to a higher class than for DSA.

Conclusion

TOF-MRA at 3 T is at least as efficient as DSA for the evaluation of intracranial aneurysm occlusion after endovascular treatment with detachable coils. We suggest that TOF-MRA at 3 T might be used as the primary method for imaging follow-up of coiled intracranial aneurysms.     

Radiation dose and image quality of X-ray volume imaging systems: cone-beam computed tomography, digital subtraction angiography and digital fluoroscopy

Objective

Radiation dose and image quality estimation of three X-ray volume imaging (XVI) systems.

Methods

A total of 126 patients were examined using three XVI systems (groups 1–3) and their data were retrospectively analysed from 2007 to 2012. Each group consisted of 42 patients and each patient was examined using cone-beam computed tomography (CBCT), digital subtraction angiography (DSA) and digital fluoroscopy (DF). Dose parameters such as dose–area product (DAP), skin entry dose (SED) and image quality parameters such as Hounsfield unit (HU), noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were estimated and compared using appropriate statistical tests.

Results

Mean DAP and SED were lower in recent XVI than its previous counterparts in CBCT, DSA and DF. HU of all measured locations was non-significant between the groups except the hepatic artery. Noise showed significant difference among groups (P?<?0.05). Regarding CNR and SNR, the recent XVI showed a higher and significant difference compared to its previous versions. Qualitatively, CBCT showed significance between versions unlike the DSA and DF which showed non-significance.

Conclusion

A reduction of radiation dose was obtained for the recent-generation XVI system in CBCT, DSA and DF. Image noise was significantly lower; SNR and CNR were higher than in previous versions. The technological advancements and the reduction in the number of frames led to a significant dose reduction and improved image quality with the recent-generation XVI system.

Key Points

? X-ray volume imaging (XVI) systems are increasingly used for interventional radiological procedures. ? More modern XVI systems use lower radiation doses compared with earlier counterparts. ? Furthermore more modern XVI systems provide higher image quality. ? Technological advances reduce radiation dose and improve image quality.     

Whole-brain CT digital subtraction angiography of cerebral dural arteriovenous fistula using 320-detector row CT

Introduction

The purpose of this study was to evaluate the usefulness of CT digital subtraction angiography (CTDSA) by using 320-detector row CT in the diagnosis and classification of cerebral dural arteriovenous fistula (dAVF) and comparing it with DSA as the standard reference.

Methods

A total of 29 CTDSA/DSA from 25 patients with dAVF were retrospectively evaluated by two neuroradiologists. The presence, Cognard classification, and feeding arteries of dAVFs on CTDSA were assessed according to DSA.

Results

DSA depicted 33 dAVFs in 28 cases. By consensus reading, CTDSA correctly detected 32 dAVFs in 27 cases and properly graded 31 lesions. The intermodality agreement for the presence and classification of dAVFs was excellent (kappa?=?0.955 and 0.921, respectively). CTDSA detected 77 of 109 feeding arteries (70.6 %) in 25 cases. The intermodality agreement for the feeding arteries was good (kappa?=?0.713).

Conclusion

Although CTDSA is limited in temporal and spatial resolution in comparison with DSA, it is an effective non-invasive tool for the detection and classification of dAVF.     

Comparison between 64-row CT angiography and digital subtraction angiography in the study of lower extremities: personal experience

Purpose

This study was undertaken to evaluate the potential of 64-row multislice computed tomography (CT) versus digital subtraction angiography (DSA) in detecting significant lesions of lower-extremity inflow and runoff arteries.

Materials and methods

Fifty-three patients underwent 64-row multislice CT and DSA over a mean of 36 days. The vascular tree was divided into 33 segments. Three readers independently reviewed the axial CT scans and multiplanar oblique and two- and three-dimensional reconstructions (maximum intensity projection and volume rendering) images to assess degree of stenosis according to four categories: 1 (0%–49% stenosis); 2 (50%–99% stenosis); 3 (occluded); 4 (not evaluable). In all cases, DSA was performed by arterial catheterisation.

Results

In 53 patients, 1,440 segments were evaluated (infrarenal aorta and 16 arterial segments for each leg; 42 bilateral studies, 11 unilateral studies). Compared with DSA, CT angiography yielded 97.2% sensitivity, 97% specificity, 92.5% positive predictive value, 98.9% negative predictive value, 97.1% diagnostic accuracy and 95.4% concordance on the degree of stenosis.

Conclusions

Sixty-four-row multislice CT proved to be helpful in detecting haemodynamically significant lesions in peripheral arterial occlusive disease and improved the results obtained with 4- and 16-slice multidetector CT. In addition, owing to the high spatial resolution and rigorous technique, no variations in the data obtained below the knee were detected, overcoming a limitation of earlier generations of CT scanners.     

Interobserver agreement for the detection of atherosclerotic plaque in coronary CT angiography: comparison of two low-dose image acquisition protocols with standard retrospectively ECG-gated reconstruction

Background

We compared the interobserver variability concerning the detection of calcified and non-calcified plaque in two different low-dose and standard retrospectively gated protocols for coronary CTA.

Methods

150 patients with low heart rates and less than 100?kg body weight were randomised and examined by contrast-enhanced dual-source CT coronary angiography (100?kV, 320?mAs). 50 patients were examined with prospectively ECG-triggered axial acquisition, 50 patients with prospectively ECG-triggered high pitch spiral acquisition, and 50 patients using spiral acquisition with retrospective ECG gating. Two investigators independently analysed the datasets concerning the presence of calcified and non-calcified plaque on a per-segment level.

Results

Mean effective dose was 1.4?±?0.2?mSv for axial, 0.8?±?0.07?mSv for high-pitch spiral, and 5.3?±?2.6?mSV for standard spiral acquisition (P?P?Conclusion Low-dose coronary CT angiography permits the detection of coronary atherosclerotic plaque with good interobserver agreement.

Key Points

? Low-dose CT protocols permit coronary plaque detection with good interobserver agreement. ? Image noise is a major predictor of interobserver variability. ? Interobserver agreement is significantly higher for calcified than for non-calcified plaque.     

Thrombus imaging in acute stroke: correlation of thrombus length on susceptibility-weighted imaging with endovascular reperfusion success

Objectives

Susceptibility-weighted imaging (SWI) enables visualization of thrombotic material in acute ischemic stroke. We aimed to validate the accuracy of thrombus depiction on SWI compared to time-of-flight MRA (TOF-MRA), first-pass gadolinium-enhanced MRA (GE-MRA) and digital subtraction angiography (DSA). Furthermore, we analysed the impact of thrombus length on reperfusion success with endovascular therapy.

Methods

Consecutive patients with acute ischemic stroke due to middle cerebral artery (MCA) occlusions undergoing endovascular recanalization were screened. Only patients with a pretreatment SWI were included. Thrombus visibility and location on SWI were compared to those on TOF-MRA, GE-MRA and DSA. The association between thrombus length on SWI and reperfusion success was studied.

Results

Eighty-four of the 88 patients included (95.5 %) showed an MCA thrombus on SWI. Strong correlations between thrombus location on SWI and that on TOF-MRA (Pearson’s correlation coefficient 0.918, P?<?0.001), GE-MRA (0.887, P?<?0.001) and DSA (0.841, P?<?0.001) were observed. Successful reperfusion was not significantly related to thrombus length on SWI (P?=?0.153; binary logistic regression).

Conclusions

In MCA occlusion thrombus location as seen on SWI correlates well with angiographic findings. In contrast to intravenous thrombolysis, thrombus length appears to have no impact on reperfusion success of endovascular therapy.

Key Points

? SWI helps in assessing location and length of thrombi in the MCA ? SWI, MRA and DSA are equivalent in detecting the MCA occlusion site ? SWI is superior in identifying the distal end of the thrombus ? Stent retrievers should be deployed over the distal thrombus end ? Thrombus length did not affect success of endovascular reperfusion guided by SWI     

Semi-automatic quantitative measurements of intracranial internal carotid artery stenosis and calcification using CT angiography

Introduction

Intracranial carotid artery atherosclerotic disease is an independent predictor for recurrent stroke. However, its quantitative assessment is not routinely performed in clinical practice. In this diagnostic study, we present and evaluate a novel semi-automatic application to quantitatively measure intracranial internal carotid artery (ICA) degree of stenosis and calcium volume in CT angiography (CTA) images.

Methods

In this retrospective study involving CTA images of 88 consecutive patients, intracranial ICA stenosis was quantitatively measured by two independent observers. Stenoses were categorized with cutoff values of 30% and 50%. The calcification in the intracranial ICA was qualitatively categorized as absent, mild, moderate, or severe and quantitatively measured using the semi-automatic application. Linear weighted kappa values were calculated to assess the interobserver agreement of the stenosis and calcium categorization. The average and the standard deviation of the quantitative calcium volume were calculated for the calcium categories.

Results

For the stenosis measurements, the CTA images of 162 arteries yielded an interobserver correlation of 0.78 (P?Conclusions Quantitative degree of stenosis measurement of the intracranial ICA on CTA is feasible with a good interobserver agreement ICA. Qualitative calcium categorization agrees well with quantitative measurements.     

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.     

Nonenhanced ECG-gated time-resolved 4D Steady-state free precession (SSFP) MR angiography (MRA) for assessment of cerebral collateral flow: comparison with digital subtraction angiography (DSA)

Objectives

To evaluate a nonenhanced time-resolved 4D SSFP MRA for dynamic visualization of intracranial collateral blood flow.

Methods

22 patients (59.0?±?11.8 years) with steno-occlusive disease of brain-supplying arteries were included in this study. 4D SSFP MRA of the intracranial arteries was acquired with 15 temporal phases and a temporal resolution of 115 ms using 1.5 T MR. Cerebral DSA served as the reference standard and was available in all patients.

Results

Nonenhanced 4D SSFP MRA allowed for detailed dynamic visualization of blood flow in the circle of Willis and its branches in 21 of 22 (95.5%) patients. Collateral flow was excluded with both 4D SSFP MRA and DSA in 4 patients. In 17 patients, DSA detected anterior collateral flow (n?=?8), posterior collateral flow via the right (n?=?8) and left (n?=?7) posterior communicating artery as well as patent EC-IC bypasses (n?=?8). 29 of 31 collateral flow pathways were visualized by 4D SSFP MRA. As compared to DSA, 4D SSFP MRA showed a high sensitivity (92.3%), specificity (100%), positive predictive value (100%) and negative predictive value (95.2%) for visualization of intracranial collateral flow.

Conclusions

4D SSFP MRA is a promising non-invasive imaging technique for dynamic visualization of intracranial collateral flow.     

Evaluation of intracranial aneurysms with high-resolution MR angiography using single-artery highlighting technique: correlation with digital subtraction angiography

Purpose

The authors investigated the effectiveness of high-resolution magnetic resonance angiography (MRA) using a single-artery highlighting technique for the accurate diagnosis of intracranial aneurysms at 3.0 T in a large cohort of patients with suspected intracranial aneurysms against the current gold standard, i.e. cerebral angiography.

Methods

A total of 307 patients with suspected aneurysms were referred for three-dimensional time-of-flight MRA (3D-TOF-MRA) prior to digital subtraction angiography (DSA). We summarised patient-based, aneurysm-based and vessel-based diagnostic performance parameters, namely, accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for detecting intracranial aneurysms with 3D-TOF-MRA. Interobserver agreement was calculated with the kappa (κ) statistic.

Results

Patient-based accuracy was 98.1%, sensitivity 99.5%, specificity 95.3%, PPV 97.6% and NPV 99% according to observer A; and 97.7%, 99.5%, 94.3%, 97.1% and 99%, respectively, according to observer B. Aneurysmbased accuracy was 98.3%, sensitivity 99.6%, specificity 95.2%, PPV 98.1% and NPV 99% according to observer A, and 98.0%, 99.6%, 94.3%, 97.7% and 99%, respectively, according to observer B. Vessel-based accuracy was 99.0%, sensitivity 99.6%, specificity 98.7%, PPV 97.8%, and NPV 99.7% according to observer A, and 98.9%, 99.6%, 98.5%, 97.3%, and 99.7%, respectively, according to observer B. Interobserver reading differences were not significant. The interobserver agreement was good, with a kappa (κ) value of 0.931 for patient-based evaluation, 0.934 for aneurysmbased evaluation and 0.953 for vessel-based evaluation.

Conclusions

Our results demonstrate the effectiveness of high-resolution MRA using a single-artery-highlighting technique for accurate diagnosis of intracranial aneurysms in a large cohort of patients with suspected aneurysms.     

Brain arteriovenous malformation diagnosis: value of time-resolved contrast-enhanced MR angiography at 3.0T compared to DSA

Introduction

This study was conducted in order to evaluate the value of time-resolved contrast-enhanced magnetic resonance angiography (TR-CE-MRA) with a 3.0-T magnetic field compared to digital subtraction angiography (DSA) as the reference standard for the diagnosis of brain arteriovenous malformation (bAVM).

Methods

Nineteen patients with 19 angiographically confirmed untreated bAVM were investigated with both DSA and TR-CE-MRA for the initial diagnosis. Examinations were compared by two independent readers. Interobserver agreement and intermodality agreement with respect to nidus size, arterial feeders, and venous drainage were determined using the K statistic test. Also, the quality of the TR-CE-MRA images was evaluated.

Results

Seventeen of the 19 bAVM (89.5%) detected with DSA were diagnosed with TR-CE-MRA. Interobserver agreement for TR-CE-MRA was good for nidus size, venous drainage, and arterial feeders (K?=?0.75, 95% CI 0.50–1.00; K?=?0.77, 95% CI 0.54–1.00; and K?=?0.80, 95% CI 0.59–1.00 respectively). Intermodality agreement was good for nidus size and venous drainage (K?=?0.75, 95% CI 0.49–1.00 and K?=?0.77, 95% CI 0.54–1.00, respectively) and moderate for arterial feeders (K?=?0.44, 95% CI 0.17–0.70).

Conclusion

TR-CE-MRA at 3.0?T has a good sensitivity for bAVM detection and good agreement with DSA for determining nidus size and the type of venous drainage, suggesting that TR-CE-MRA is potentially a reliable tool for the diagnosis and assessment of bAVMs. However, it still suffers from low spatial resolution and vessel superposition, making differentiation of the arterial feeders of the nidus difficult at times.     

Reliability of change in lumbar MRI findings over time in patients with and without disc prosthesis—comparing two different image evaluation methods

Objectives

To assess the reliability of change in lumbar magnetic resonance imaging (MRI) findings evaluated retrospectively by direct comparison of images and by non-comparison.

Materials and methods

Pre-treatment and 2-year follow-up MRI was performed in 126 patients randomized to disc prosthesis surgery or non-surgical treatment. Two experienced radiologists independently evaluated progress and regress for Modic changes, disc findings, and facet arthropathy (FA) at L3/L4, L4/L5, and L5/S1, both by non-comparison and by comparison of initial and follow-up images. FA was evaluated at all levels, and other findings at non-operated levels. We calculated prevalence- and bias-adjusted kappa (PABAK) values for interobserver agreement. The impact of an adjacent prosthesis (which causes artefacts) and image evaluation method on PABAK was assessed using generalized estimating equations.

Results

Image comparison indicated good interobserver agreement on progress and regress (PABAK 0.63?1.00) for Modic changes, posterior high-intensity zone, disc height, and disc contour at L3-S1 and for nucleus pulposus signal and FA at L3/L4; and moderate interobserver agreement (PABAK 0.46?0.59) on decreasing nucleus signal and increasing FA at L4-S1. Image comparison indicated lower (but fair) interobserver agreement (PABAK 0.29) only for increasing FA at L5/S1 in patients with prosthesis in L4/L5 and/or L5/S1. An adjacent prosthesis had no overall impact on PABAK values (p?≥?0.22). Comparison yielded higher PABAK values than non-comparison (p?<?0.001).

Conclusions

Regarding changes in lumbar MRI findings over time, comparison of images can provide moderate or good interobserver agreement, and better agreement than non-comparison. An adjacent prosthesis may not reduce agreement on change for most findings.     

US-guided diffuse optical tomography for breast lesions: the reliability of clinical experience

Purpose

To prospectively assess the reliability of US-guided diffuse optical tomography (US-DOT) using interobserver agreement for the diagnosis of breast lesions with individual real-time imaging and to assess the interobserver agreement of conventional sonography (US) combined with US-DOT for differentiation between benignity and malignancy breast lesions.

Materials and Methods

An Institutional Review Board approved this study, and all subjects provided written informed consent. 122 breast lesions in 111 patients evaluated with US-guided core biopsy were included. Assessments with US and US-DOT for cases subjected to biopsy were obtained by two radiologists using individual real-time imaging prior to biopsy and were prospectively recorded by each performer. With DOT, the total haemoglobin concentration (THC) for each breast lesion was measured. Histopathological results from US-guided biopsies were used as a reference standard. To assess measurement interobserver agreement, the intraclass correlation coefficient (ICC) and the Bland-Altman plot were used for THC in US-DOT and the kappa values and ROC analysis were used to evaluate the diagnostic performances of the US BI-RADS final assessment in US and combined US and US-DOT.

Results

Of 122 US-guided core biopsied lesions, 83 (68.0%) were diagnosed as benign, and 39 (32.0%) as malignant. Excellent correlation was seen in the THC in US-DOT (ICC score 0.796; 95% confidence interval, 0.708?C0.857). The interobserver agreement in BI-RADS final assessment with US and US-DOT (almost perfect; ???=?0.8618) was improved compared with that of US (substantial agreement, ???=?0.6574). However, the overall areas under the ROC curve did not show significant differences between US and combined US and US-DOT, 0.8894 and 0.8975, respectively (P?=?0.981).

Conclusions

The reliability of THC in US-DOT showed excellent correlation in overall real-time performance. Although the inter-observer agreement for BI-RADS final assessment of US was improved by using US-DOT, the performances of radiologists with respect to the characterization of breast masses as benign or malignant were not significantly improved with US-DOT.     

Single-portal-phase low-tube-voltage dual-energy CT for short-term follow-up of acute pancreatitis: evaluation of CT severity index,interobserver agreement and radiation dose

Objectives

To intra-individually compare single-portal-phase low-tube-voltage (100-kVp) computed tomography (CT) with 120-kVp images for short-term follow-up assessment of CT severity index (CTSI) of acute pancreatitis, interobserver agreement and radiation dose.

Methods

We retrospectively analysed 66 patients with acute pancreatitis who underwent initial dual-contrast-phase CT (unenhanced, arterial, portal phase) at admission and short-term (mean interval 11.4 days) follow-up dual-contrast-phase dual-energy CT. The 100-kVp and linearly blended images representing 120-kVp acquisition follow-up CT images were independently evaluated by three radiologists using a modified CTSI assessing pancreatic inflammation, necrosis and extrapancreatic complications. Scores were compared with paired t test and interobserver agreement was evaluated using intraclass correlation coefficients (ICC).

Results

Mean CTSI scores on unenhanced, portal- and dual-contrast-phase images were 4.9, 6.1 and 6.2 (120 kVp) and 5.0, 6.0 and 6.1 (100 kVp), respectively. Contrast-enhanced series showed a higher CTSI compared to unenhanced images (P?P?>?0.7). CTSI scores were comparable for 100-kVp and 120-kVp images (P?>?0.05). Interobserver agreement was substantial for all evaluated series and subcategories (ICC 0.67–0.93). DLP of single-portal-phase 100-kVp images was reduced by 41 % compared to 120-kVp images (363.8 versus 615.9 mGy cm).

Conclusions

Low-tube-voltage single-phase 100-kVp CT provides sufficient information for follow-up evaluation of acute pancreatitis and significantly reduces radiation exposure.

Key Points

? Single-portal-phase CT provides sufficient evaluation for follow-up of acute pancreatitis. ? Follow-up CT does not benefit from unenhanced or arterial-phase acquisition. ? CT severity index scores are equal for dual-contrast-phase 100-/120-kVp acquisition (P?>?0.05). ? 100-kVp single-portal-phase follow-up CT of acute pancreatitis significantly reduces radiation exposure.     

Comparison of 3D computer-aided with manual cerebral aneurysm measurements in different imaging modalities

Introduction

To compare intra- and inter-observer reliability of aneurysm measurements obtained by a 3D computer-aided technique with standard manual aneurysm measurements in different imaging modalities.

Methods

A total of 21 patients with 29 cerebral aneurysms were studied. All patients underwent digital subtraction angiography (DSA), contrast-enhanced (CE-MRA) and time-of-flight magnetic resonance angiography (TOF-MRA). Aneurysm neck and depth diameters were manually measured by two observers in each modality. Additionally, semi-automatic computer-aided diameter measurements were performed using 3D vessel surface models derived from CE- (CE-com) and TOF-MRA (TOF-com) datasets. Bland–Altman analysis (BA) and intra-class correlation coefficient (ICC) were used to evaluate intra- and inter-observer agreement.

Results

BA revealed the narrowest relative limits of intra- and inter-observer agreement for aneurysm neck and depth diameters obtained by TOF-com (ranging between ±5.3 % and ±28.3 %) and CE-com (ranging between ±23.3 % and ±38.1 %). Direct measurements in DSA, TOF-MRA and CE-MRA showed considerably wider limits of agreement. The highest ICCs were observed for TOF-com and CE-com (ICC values, 0.92 or higher for intra- as well as inter-observer reliability).

Conclusion

Computer-aided aneurysm measurement in 3D offers improved intra- and inter-observer reliability and a reproducible parameter extraction, which may be used in clinical routine and as objective surrogate end-points in clinical trials.     

Accuracy and safety of CO2 digital subtraction angiography during endovascular treatment of symptomatic peripheral artery occlusive disease. A prospective study on Egyptian patients

Purpose

To study the efficacy, safety and clinical outcome of carbon dioxide DSA during angioplasty procedures for patients with predominant femoropopliteal segment occlusive lesions, aiming to reduce possible allergic reactions and potential nephrotoxicity.

Susceptibility-weighted angiography for the detection of high-flow intracranial vascular lesions: preliminary study

Objectives

Susceptibility-weighted magnetic resonance imaging (MRI) sequences may demonstrate various signal intensities of draining veins in cases of high-flow vascular malformation (HFVM), including arteriovenous malformation (AVM) and dural arteriovenous fistula (dAVF). Our objective was to evaluate susceptibility-weighted angiography (SWAN) for the detection of HFVM.

Methods

Fifty-eight consecutive patients with a suspected intracranial vascular malformation were explored with SWAN and post-contrast MRI sequences at 3 T. The diagnosis of slow-flow vascular malformation (SFVM), including developmental venous anomaly (DVA) or brain capillary telangiectasia (BCT), was based on MRI. Patients with suspected HFVM underwent digital subtraction angiography (DSA). SWAN images were analysed by three blinded readers according to a three-point scale of the venous signal.

Results

Thirty-one patients presented 35 SFVM (26 DVA and 9 BCT) that systematically appeared hypointense on SWAN images. In patients with atypical MRI findings, DSA revealed one patient with an atypical DVA and 26 patients with HFVM (22 AVM and 4 dAVF). SWAN revealed at least one venous hyperintensity in all patients with HFVM. Agreement between readers was excellent.

Conclusions

SWAN appears reliable for characterising blood flow dynamics in brain veins. In clinical practice, SWAN can routinely rule out HFVM in patients with atypical brain veins.

Key Points

? Susceptibility-weighted angiography (SWAN) offers new perspectives for detecting intracranial vascular malformations. ? SWAN sequence provides non-invasive characterisation of blood flow dynamics. ? SWAN can differentiate between high and slow flowing venous blood. ? SWAN can routinely rule out high-flow vascular malformations.     

MRI screening for silicone breast implant rupture: accuracy,inter- and intraobserver variability using explantation results as reference standard

Objectives

The recall of Poly Implant Prothèse (PIP) silicone breast implants in 2010 resulted in large numbers of asymptomatic women with implants who underwent magnetic resonance imaging (MRI) screening. This study’s aim was to assess the accuracy and interobserver variability of MRI screening in the detection of rupture and extracapsular silicone leakage.

Methods

A prospective study included 107 women with 214 PIP implants who underwent explantation preceded by MRI. In 2013, two radiologists blinded for previous MRI findings or outcome at surgery, independently re-evaluated all MRI examinations. A structured protocol described the MRI findings. The ex vivo findings served as reference standard.

Results

In 208 of the 214 explanted prostheses, radiologists agreed independently about the condition of the implants. In five of the six cases they disagreed (2.6 %), but subsequently reached consensus. A sensitivity of 93 %, specificity of 93 %, positive predictive value of 77 % and negative predictive value of 98 % was found. The interobserver agreement was excellent (kappa value of 0.92).

Conclusions

MRI has a high accuracy in diagnosing rupture in silicone breast implants. Considering the high kappa value of interobserver agreement, MRI appears to be a consistent diagnostic test. A simple, uniform classification, may improve communication between radiologist and plastic surgeon.

Key points

? MRI has a high accuracy in diagnosing rupture in silicone breast implants. ? MRI appears to be a consistent diagnostic test with excellent interobserver agreement. ? A simple, uniform classification system, improves communication between radiologist and plastic surgeon. ? The interobserver agreement on implant rupture is higher than on extracapsular leakage.     

The value of magnetic resonance imaging for the detection of the bleeding source in non-traumatic intracerebral haemorrhages: a comparison with conventional digital subtraction angiography

Introduction

Conventional digital subtraction angiography (DSA) is currently regarded as the gold standard in detecting underlying vascular pathologies in patients with intracerebral haemorrhages (ICH). However, the use of magnetic resonance imaging (MRI) in the diagnostic workup of ICHs has considerably increased in recent years. Our aim was to evaluate the diagnostic accuracy and yield of MRI for the detection of the underlying aetiology in ICH patients.

Methods

Sixty-seven consecutive patients with an acute ICH who underwent MRI (including magnetic resonance angiography (MRA) and DSA during their diagnostic workup) were included in the study. Magnetic resonance images were retrospectively analysed by two independent neuroradiologists to determine the localisation and cause of the ICH. DSA was used as a reference standard.

Results

In seven patients (10.4%), a DSA-positive vascular aetiology was present (one aneurysm, four arteriovenous malformations, one dural arteriovenous fistula and one vasculitis). All of these cases were correctly diagnosed by both readers on MRI. In addition, MRI revealed the following probable bleeding causes in 39 of the 60 DSA-negative patients: cerebral amyloid angiopathy (17), cavernoma (9), arterial hypertension (8), haemorrhagic transformation of an ischaemic infarction (3) and malignant brain tumour with secondary ICH (2).

Conclusion

Performing MRI with MRA proved to be an accurate diagnostic tool in detecting vascular malformations in patients with ICH. In addition, MRI provided valuable information regarding DSA-negative ICH causes, and thus had a high diagnostic yield in ICH patients.