Venous Enhancement Research Articles

Differentiation of deep venous thrombosis from femoral vein mixing artifact on routine abdominopelvic CT.

The objective of this study is to assess the performance of qualitative and quantitative imaging features for the differentiation of deep venous thrombosis (DVT) from mixing artifact on routine portal venous phase abdominopelvic CT. This retrospective study included 40 adult patients with a femoral vein filling defect on portal venous phase CT and a Duplex ultrasound (n = 36) or catheter venogram (n = 4) to confirm presence or absence of DVT. Two radiologists (R1, R2) assessed the femoral veins for various qualitative and quantitative features. 60% of patients were confirmed to have DVT and 40% had mixing artifact. Features with significantly greater frequency in DVT than mixing artifact (all p ≤ 0.006) were central location (R1 90% vs. 28%; R2 96% vs. 31%), sharp margin (R1 83% vs. 28%; R2 96% vs. 31%), venous expansion (R1 48% vs. 6%, R2 56% vs. 6%), and venous wall enhancement (R1 62% vs. 0%; R2 48% vs. 0%). DVT exhibited significantly lower mean attenuation than mixing artifact (R1 42.1 ± 20.2 vs. 57.1 ± 23.6 HU; R2 43.6 ± 19.4 vs. 58.8 ± 23.4 HU, p ≤ 0.031) and a significantly larger difference in vein diameter compared to the contralateral vein (R1 0.4 ± 0.4 vs. 0.1 ± 0.2 cm; R2 0.3 ± 0.4 vs. 0.0 ± 0.1 cm, p ≤ 0.026). At multivariable analysis, central location and sharp margin were significant independent predictors of DVT for both readers (p ≤ 0.013). Awareness of these qualitative and quantitative imaging features may improve radiologists' confidence for differentiating femoral vein DVT and mixing artifact on routine portal venous phase CT. However, given overlap with mixing artifact, larger studies remain warranted.

Dark Blood Magnetic Resonance Lymphangiography Using Dual-Agent Relaxivity Contrast (DARC-MRL): A Novel Method Combining Gadolinium and Iron Contrast Agents

The objective of this study was to develop and demonstrate a technique to eliminate venous enhancement in contrast-enhanced magnetic resonance lymphangiography through shortening T2(⁎) in the blood pool, thus allowing for a lymphatic-only map. Administration of the blood-pool iron agent ferumoxtyol in addition to intracutaneous gadolinium during contrast-enhanced magnetic resonance lymphangiography allows for suppression of vascular structures to achieve venous-free lymphatic mapping.

Implementation of a split-bolus single-pass CT protocol at a UK major trauma centre to reduce excess radiation dose in trauma pan-CT

To quantify the dose reduction and ensure that the use of a split-bolus protocol provided sufficient vascular enhancement. Between 1 January 2014 and 31 May 2014, both split bolus and traditional two-phase scans were performed on a single CT scanner (SOMATOM Definition AS+, Siemens Healthcare) using a two-pump injector (Medrad Stellant). Both protocols used Siemens' proprietary tube current and tube voltage modulation techniques (CARE dose and CARE kV). The protocols were compared retrospectively to assess the dose-length product (DLP), aortic radiodensity at the level of the coeliac axis and radiodensity of the portal vein. There were 151 trauma CT examinations during this period. Seventy-eight used the split-bolus protocol. Seventy-one had traditional two-phase imaging. One patient was excluded as they were under the age of 18 years. The radiodensity measurements for the portal vein were significantly higher (p<0.001) in the split-bolus protocol. The mean aortic enhancement in both protocols exceeded 250 HU, although the traditional two-phase protocol gave greater arterial enhancement (p<0.001) than the split-bolus protocol. The split-bolus protocol had a significantly lower (p<0.001) DLP with 43.5% reduction in the mean DLP compared to the traditional protocol. Split-bolus CT imaging offers significant dose reduction for this relatively young population while retaining both arterial and venous enhancement.

Patient-specific timing for bolus-chase peripheral MR angiography.

To develop a timing algorithm for three-station moving-table MR angiography of the peripheral arteries (pMRA) based on individual patient hemodynamics that optimizes arterial opacification and minimizes venous enhancement. Two separate patient cohorts were identified for this retrospective study. The first consisted of 71 patients for development of a patient specific timing algorithm to calculate multiple contrast agent bolus transit times at 1.5 Tesla using a spoiled gradient echo sequence. This timing data was applied to a separate group of 59 patients in which one of four predetermined pMRA protocols was performed based on a time-resolved MRA of the calves. Image quality was evaluated by two blinded readers grading venous enhancement and arterial opacification. Transit time from abdominal aorta to foot (Ao-F) ranged from 5-46 s, with a mean of 17.8 ± 8.2 s. Arteriovenous window (AVW) transit time ranged from -5 to 65 s, with a mean of 18.3 ± 16.0 s. Ischemic patients had longer injection site-to-arterial transit times (25.6 versus 20.7 s; P < 0.01). Of the 59 patients who underwent diagnostic pMRA, 81 and 83% (two readers, respectively) showed no or minimal venous enhancement, and all of the exams were diagnostic. Venous enhancement grades were significantly greater (P < 0.04) for ischemic versus nonischemic patients. Performing pMRA using a timing algorithm based on each patient's unique hemodynamics can minimize lower station venous enhancement.

Functional magnetic resonance imaging response of targeted tumor burden and its impact on survival in patients with hepatocellular carcinoma.

The aim of this study was to evaluate response of the targeted tumor burden by functional magnetic resonance imaging (MRI) including volumetric diffusion-weighted imaging and volumetric contrast-enhanced MRI (CE-MRI) and its impact on survival in patients with hepatocellular carcinoma treated with intra-arterial therapy (IAT). This institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study included 157 hepatocellular carcinoma lesions in 97 patients (78 men and 19 women; mean age, 64 years) treated with IAT. All patients had pretreatment and 3- to 4-week follow-up MRI with diffusion-weighted imaging and CE-MRI. All lesions 2 cm or larger that were targeted during the first session of IAT were segmented using research software (MR-Oncotreat) to determine targeted tumor burden relative to liver volume (%). Targeted tumor burden was stratified into low (≤10%) or high (>10%). Response using volumetric functional apparent diffusion coefficient (ADC; increase by ≥25%) and CE-MRI (decrease by ≥50% and ≥65% in arterial and venous enhancement [VE], respectively) was assessed in all targeted tumors (range, 1-11) using paired t tests. Kaplan-Meier survival analysis was performed and log-rank test was used to compare pairs of survival curves. Multivariate Cox regression analysis was performed to determine the simultaneous effect of treatment response and tumor burden on survival after adjusting for age, sex, and Child Pugh status. There was a significant increase in volumetric ADC (median, 15%; P < 0.001) and a decrease in volumetric arterial enhancement (AE) and VE (median AE, -43% and portal venous phase (PVP), -29%, respectively; P < 0.001) 3 to 4 weeks after treatment in the targeted tumor burden. Multivariable Cox regression demonstrated that both ADC response and low tumor burden were independently associated with greater survival (hazard ratios, 0.53 and 0.55; P values, 0.025 and 0.016, respectively) after adjustment for age, sex, and Child Pugh status. Multivariable Cox regression models demonstrated no statistically significant relationship between AE response and survival after adjusting for tumor burden. However, multivariable Cox regression demonstrated that VE response was associated with greater survival only in those with low tumor burden (hazard ratio, 0.10; P = 0.001), indicating a strong interaction between VE response and tumor burden. Quantifying targeted tumor burden is important in predicting patient survival when using functional MRI metrics in assessing treatment response.

Quantitative Contrast-Enhanced Magnetic Resonance Lymphangiography of the Upper Limbs in Breast Cancer Related Lymphedema: An Exploratory Study.

Background: Contrast-Enhanced Magnetic Resonance Lymphangiography (CE-MRL) presents some limitations: (i) it does not quantify lymphatic functionality; and (ii) enhancement of vascular structures may confound image interpretation. Furthermore, although CE-MRL is well described in the published literature for the lower limbs, there is a paucity of data with regards to its use in the upper limbs. In this proof-of-principle study, we propose a new protocol to perform CE-MRL in the upper limbs of patients with breast cancer-related lymphedema (BCRL) which addresses these limitations.Methods and Results: CE-MRL was performed using a previously published (morphological) protocol and the proposed protocol (quantitative) on both the ipsilateral (abnormal) and contralateral (normal) arms of patients with BCRL. The quantitative protocol employs contrast agent (CA) intradermal injections at a lower concentration to prevent T2*-related signal decay. Both protocols provided high-resolution three-dimensional images of upper limb lymphatic vessels. CA uptake curves were utilized to distinguish between lymphatic vessels and vascular structures. The quantitative protocol minimized venous enhancement and avoided spurious delays in lymphatic enhancement due to short T2* values, enabling correct CA uptake characterization. The quantitative protocol was therefore employed to measure the lymphatic fluid velocity, which demonstrated functional differences between abnormal and normal arms. The velocity values were in agreement with previously reported lymphoscintigraphy and near infra-red lymphangiography measurements.Conclusions: This work demonstrated the feasibility of CE-MRL of the upper limbs in patients with BRCL, introducing an advanced imaging and analysis protocol suitable for anatomical and functional study of the lymphatic system.

Thoracic central venous evaluation: comparison of first-pass direct versus delayed-phase indirect multidetector CT venography

PurposeThe purpose was to compare first-pass and delayed-phase thoracic computed tomography (CT) venography for the evaluation of suspected central thoracic venous pathology. Material and methodsCT images and medical records of all patients who underwent thoracic CT venography over a 5-year period were retrospectively reviewed. Both first-pass (18s) and delayed-phase (60s) venous images were obtained in all patients. The images were reviewed in random order by three readers using a semiquantitative visual grading scheme for image quality, including artifacts and the uniformity of venous enhancement. In addition, enhancement was quantitatively evaluated. The presence and type of venous pathology, and overall diagnostic confidence were recorded and compared. Reference verification was performed when available. ResultsEighteen patients formed the study group, mean age 49.5years and 28% male. Dual-arm injection was successful in 72% of exams. All readers reported more streak artifacts on first-pass imaging than delayed imaging (72%–94% vs. 27%–44%, respectively; P<.05). First-pass imaging had significantly higher measured enhancement across all central venous segments than delayed imaging (mean HU range 212–906 HU vs. 173–414 HU; P<.05) but also had significantly more heterogeneous enhancement (mean S.D. range 75–1058 HU vs. 67–378 HU; P<.05). For overall diagnosis, reader agreement, accuracy, and confidence levels were higher for delayed-phase images (P<.05). ConclusionIndirect thoracic CT venography using delayed-phase imaging alone may be sufficient for evaluating clinically suspected central venous abnormality.

Diagnostic Value of Semiquantitative Analysis of Dynamic Susceptibility Contrast Magnetic Resonance Imaging with GD-EOB-DTPA in Focal Liver Lesions Characterization: A Feasibility Study.

Purpose. To assess the diagnostic accuracy of dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSCE-MRI) in differentiation between benign and malignant liver lesions by assessment of tumoral perfusion parameters. Methods Materials. Seventy-three patients with known focal liver lesions, including 45 benign (16 FNH, 27 angiomas, and 2 abscesses) and 28 malignant ones (17 metastases, 9 HCCs, and 2 cholangiocarcinoma) underwent 1.5 T MRI upper abdominal study, with standard protocol that included dynamic contrast-enhanced sequences. On dedicated workstation, time-intensity curves were determined and the following perfusion parameters were calculated: relative arterial, venous and late enhancement (RAE, RVE, RLE), maximum enhancement (ME), relative enhancement (RE), and time to peak (TTP). Results. All diagnoses were established either by histopathology or imaging follow-up. Perfusion mean values calculated in benign lesions were RAE 33.8%, RVE 66.03%, RLE 80.63%, ME 776.00%, MRE 86.27%, and TTP 146.95 sec. Corresponding perfusion values calculated in malignant lesions were RAE 22.47%, RVE 40.54%, RLE 47.52%, ME 448.78%, MRE 49.85%, and TTP 183.79 sec. Statistical difference (p < 0.05) was achieved in all the perfusion parameters calculated, obtaining different cluster of perfusion kinetics between benign and malignant lesions. Conclusions. DSCE-MRI depicts kinetic differences in perfusion parameters among the different common liver lesions, related to tumour supply and microvascular characteristics.

Dynamic contrast-enhanced ultrasound (DCE-US) for the characterization of hepatocellular carcinoma and cholangiocellular carcinoma.

In a prospective study, we compared the different perfusion kinetics of HCC and ICC using dynamic contrast-enhanced ultrasound (DCE-US). Patients with proven HCC and ICC were included. Three-minute video clips of CEUS examinations (CPS - low MI mode) after a bolus injection of 1.2 ml SonoVue were recorded and analyzed with quantification software (VueBox). Parameters for the arterial contrast enhancement [rise time (RT), time-to-peak (TTP)] towards portal venous contrast enhancement [mean transit time (local) (mTTl) and fall time (FT)] were quantified. Furthermore, contrast wash-out after peak enhancement (PE) (40 s, 80 s, 100 s and 120 s after PE) was compared between HCC and ICC. 43 patients with proven HCC (n = 23 HCC; cirrhosis n = 16) and ICC (n = 20 ICC; Cirrhosis n = 6) were examined. No statistical difference of the arterial DCEUS parameters was found between HCC and ICC. Contrast enhancement of the portal venous and late phases showed significantly lower values in the ICC group indicating early wash-out of the contrast agent: mTTl (p = 0.0209): HCC 118.4 s (SD± 88.4); ICC 64.8 s (SD± 49.7). FT (p = 0.0433): HCC 42.5 s (SD± 27.7); ICC 27.7 s (SD± 16.2). The percental loss of intensity at a definite time point after PE was significantly higher in ICC than in HCC lesions. DCE-US is able to detect and quantify differences in perfusion kinetics between HCC and ICC. Whereas arterial contrast enhancement patterns may overlap between HCC and ICC, a timed characterization of wash-out kinetics may offer an additional tool to characterize HCC and ICC. The presence of a rapid loss of signal intensity in the early portal venous phase is significantly higher in ICC than in HCC lesions.

Saline-enhanced ultrasonography: prediction of X-ray appearance of hepatic venography in patients with cirrhosis

Objective.To examine the efficacy of saline-enhanced ultrasound (US) in predicting the X-ray appearance of hepatic venography. Materials and methods.This prospective study consisted of 50 cirrhosis patients (31 males and 19 females; mean age, 64.2 ± 11.1 years). US patterns in the liver, after injection of agitated saline via balloon-occluded catheter, were evaluated with respect to the findings of CO2-enhanced hepatic venogram. Results.US demonstrated two patterns: type I showing positive parenchymal enhancement (40 patients) and type II showing negative parenchymal enhancement with detection of hepatic vein (10 patients). There were also two patterns shown by hepatic venography: type A showing retrograde detection of intrahepatic portal vein (41 patients) and type B showing hepatic venous enhancement via intrahepatic venous–venous communications with no detection of intrahepatic portal vein (9 patients). All patients with type I showed retrograde detection of intrahepatic portal vein via hepatic sinusoid on X-ray venograms (type A). Of the 10 patients with type II, nine showed type B and one showed type A. Sensitivity and specificity of type I US pattern to predict the detection of intrahepatic portal vein on the venogram were 100% and 90%, respectively. There was no significant difference in hepatic venous pressure gradient or wedged hepatic venous pressure between patients with type I and type II. Conclusions.Saline-enhanced US is effective in predicting the findings of hepatic venogram. As type II strongly suggests the shunt-modified venogram, image taking in these cases would be superfluous with the added advantage of avoiding unnecessary radiation exposure.

Hepatocellular carcinoma enhancement on contrast-enhanced CT and MR imaging: response assessment after treatment with sorafenib: preliminary results

This study was undertaken to compare response evaluation criteria in solid tumours (RECIST) 1.1 and modified RECIST (mRECIST) in patients with unresectable hepatocellular carcinoma (HCC) on sorafenib, and to describe HCC enhancement changes before and after sorafenib treatment. Seventeen patients (12 men, 5 women; mean age 69 years; age range 58-79 years) were included. Tumour response was assessed according to RECIST and mRECIST. Two readers placed a region of interest (ROI) within each target lesion, on the portion showing enhancement during the arterial phase. The lesion attenuation values measured within the ROIs on computed tomography or the signal intensity measured on magnetic resonance imaging, during the unenhanced phase, hepatic arterial phase and venous phase were recorded. Changes in arterial and venous contrast enhancement before and after treatment were compared among the mRECIST groups using Mann-Whitney U test. Agreement between mRECIST and RECIST was good (Cohen's k coefficient, 0.791). Patients with partial response had a greater decrease in arterial enhancement (-79.8%) than did patients with stable disease (SD) (-24.8%; p = 0.011) or progressive disease (PD) (-32.9%; p = 0.034). No statistically significant difference in arterial enhancement variation was found among patients with SD and PD. No statistically significant difference in venous enhancement was found among the mRECIST groups. mRECIST showed a more favourable response compared to RECIST 1.1 in patients with unresectable HCC receiving sorafenib.

Interobserver agreement of semi-automated and manual measurements of functional MRI metrics of treatment response in hepatocellular carcinoma

PurposeTo assess the interobserver agreement in 50 patients with hepatocellular carcinoma (HCC) before and 1 month after intra-arterial therapy (IAT) using two semi-automated methods and a manual approach for the following functional, volumetric and morphologic parameters: (1) apparent diffusion coefficient (ADC), (2) arterial phase enhancement (AE), (3) portal venous phase enhancement (VE), (4) tumor volume, and assessment according to (5) the Response Evaluation Criteria in Solid Tumors (RECIST), and (6) the European Association for the Study of the Liver (EASL). Materials and methodsThis HIPAA-compliant retrospective study had institutional review board approval. The requirement for patient informed consent was waived. Tumor ADC, AE, VE, volume, RECIST, and EASL in 50 index lesions was measured by three observers. Interobserver reproducibility was evaluated using intraclass correlation coefficients (ICC). P<0.05 was considered to indicate a significant difference. ResultsSemi-automated volumetric measurements of functional parameters (ADC, AE, and VE) before and after IAT as well as change in tumor ADC, AE, or VE had better interobserver agreement (ICC=0.830–0.974) compared with manual ROI-based axial measurements (ICC=0.157–0.799). Semi-automated measurements of tumor volume and size in the axial plane before and after IAT had better interobserver agreement (ICC=0.854–0.996) compared with manual size measurements (ICC=0.543–0.596), and interobserver agreement for change in tumor RECIST size was also higher using semi-automated measurements (ICC=0.655) compared with manual measurements (ICC=0.169). EASL measurements of tumor enhancement in the axial plane before and after IAT ((ICC=0.758–0.809), and changes in EASL after IAT (ICC=0.653) had good interobserver agreement. ConclusionSemi-automated measurements of functional changes assessed by ADC and VE based on whole-lesion segmentation demonstrated better reproducibility than ROI-based axial measurements, or RECIST or EASL measurements.

Towards finger-vein image restoration and enhancement for finger-vein recognition

Biometric recognition based on human finger-vein patterns is an emerging technique and has been receiving increasing attention. Due to light attenuation in biological tissue, the collected finger-vein images are often seriously degraded. This makes finger-vein feature representation unreliable, and inevitably impairs the accuracy of finger-vein recognition. Exploring suitable ways of finger-vein image restoration and enhancement is indispensable for finger-vein based personal identification. In this paper, we first analyze the intrinsic factors causing the degradation of finger-vein images, and propose a simple but effective scattering removal method to improve the visibility of finger-vein images. Moreover, to handle venous region enhancement problem effectively, a directional filtering method based on a family of Gabor filters is proposed. Finally, a Phase-Only-Correlation strategy is used to measure the similarity of the enhanced finger-vein images. Experiments performed on a large finger-vein image database show that the proposed method is effective and reliable in finger-vein image restoration and enhancement.

Retrospective assessment of the utility of an iron‐based agent for contrast‐enhanced magnetic resonance venography in patients with endstage renal diseases

To compare abdominopelvic and lower extremity venous enhancement in contrast-enhanced magnetic resonance venography (ceMRV), using iron-based ferumoxytol and gadolinium-based gadofosveset. This was a Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective study. Thirty-four patients were identified who had undergone ceMRV using either ferumoxtyol (Group A, all with chronic renal insufficiency) or gadofosveset (Group B). Two radiologists rated confidence for evaluation of the major abdominopelvic and lower extremity veins from 4 (excellent confidence) to 1 (nondiagnostic). A third radiologist measured signal intensity ratios (SIRs) of venous segments compared with adjacent muscles. Scores were compared using repeated-measures analysis of variance (ANOVA). The medical record was searched for contemporaneous imaging to confirm the ceMRV findings. In Group A, 14/225 venous segments were thrombosed, compared with 18/282 in Group B. There was no statistically significant difference between confidence scores (3.79 ± 0.44 vs. 3.85 ± 0.44, P = 0.34) or SIRs (2.40 ± 0.73 vs. 2.38 ± 0.51, P = 0.51) for patent segments in the two groups, nor were confidences scores (3.89 ± 0.29 vs. 3.72 ± 0.46, P = 0.31) or SIRs (0.90 ± 0.12 vs. 0.84 ± 0.19, P = 0.31) significantly different for thrombosed segments. Contemporaneous imaging confirmed ceMRV findings in 227 segments. ceMRV can be performed with ferumoxytol, yielding similar image quality to a blood pool gadolinium-based contrast agent.

MDCT of Adrenal Masses: Can Dual-Phase Enhancement Patterns Be Used to Differentiate Adenoma and Pheochromocytoma?

The purpose of this study was to compare enhancement of adrenal adenomas and pheochromocytomas during dual-phase (arterial and venous phases) CT performed with currently used MDCT protocols with the goal of defining enhancement patterns predictive of pathologic findings. Pathologically proven pheochromocytomas were retrospectively compared with adrenal adenomas. Inclusion criteria for adenomas, collected by searching the radiology database, were confirmatory adrenal CT (unenhanced with or without washout) and absence of clinical indicators of pheochromocytoma. A fellowship-trained attending radiologist blinded to the pathologic diagnosis reviewed existing images from dual-phase IV contrast-enhanced CT examinations to measure enhancement of adrenal lesions and characterize the appearance (homogeneous versus heterogeneous). Student t test analysis was performed to compare arterial and venous phase enhancement levels. The findings in 39 patients with 41 adenomas were compared with those in 10 patients with 12 pheochromocytomas. Mean arterial and venous enhancement of adenomas at 37 HU (-6 to 85 HU) and 60 HU (16-133 HU) was significantly lower than that of pheochromocytomas at 104 HU (42-190 HU) and 119 HU (61-195 HU) (p < 0.001). No adenoma was more than 85-HU enhancing in the arterial phase, and 58% of pheochromocytomas were more than 110-HU enhancing. Most adenomas (85%) were more enhancing in the venous phase. No adenoma was more enhancing in the arterial phase, but 25% (3/12) of pheochromocytomas were. Most (58%) pheochromocytomas were heterogeneous in appearance, compared with 22% of adenomas. For indeterminate adrenal masses identified at dual-phase IV contrast-enhanced CT, higher enhancement during the arterial phase, arterial phase enhancement levels greater than 110 HU, and lesion heterogeneity should prompt consideration of pheochromocytoma.

Metanephric adenoma: A report of two cases and review of the literature

Metanephric adenoma (MA) is a rare benign renal neoplasm of originating in the epithelial cells, which is often difficult to distinguish from malignant neoplasms preoperatively. In this study we present two cases of patients with MA with the aim to analyze the clinical manifestations, imaging, pathology, diagnosis and treatment of MA. Computed tomography (CT) of the first case revealed a solid well-demarcated tumor, 5.5 × 5.4 cm in diameter. Ultrasound examination of the second patient revealed a hypoechoic mass with solid aspect and irregular limits in the upper pole of the right kidney. CT confirmed the presence of a 4 cm expansive tumoral formation with intermediate attenuation and minimum venous contrast enhancement at that anatomic site. The two cases underwent surgery and the patients were free from recurrence after a follow-up period of 18 months to 2 years. We also present a supplementary review of previously published cases and related literature.

Improved Quality and Diagnostic Confidence Achieved by Use of Dose-Reduced Gadolinium Blood-Pool Agents for Time-Resolved Intracranial MR Angiography

Time-resolved MRA with the use of bolus injection of paramagnetic agents has proved valuable in neurovascular imaging. Standard contrast agents have limited blood-pool residence times, motivating the development of highly protein-bound blood-pool agents with greater relaxivity and longer intravascular residence, affording improved image quality at lesser doses. This study represents the first comparison of blood-pool agents to standard agents in time-resolved cerebral MRA. One hundred datasets were acquired at 1.5 T by use of a standardized, time-resolved MRA protocol. Patients received either unit dosing of a standard extracellular agent at 0.1 mmol/kg or a blood-pool agent at 0.03 mmol/kg. Peak arterial and venous enhancement phases were identified and subsequently scored qualitatively by use of a 4-point Likert scale, with attention to 6 vascular segments: 1) intracranial ICA; 2) MCA M1; 3) MCA M2; 4) MCA M3; 5) deep cerebral veins; and 6) dural venous sinuses. Fifty MR angiographies were acquired with each agent. No significant differences were found between agents in generation of uncontaminated arteriograms. Blood-pool agents, at 67% dose reduction, were of significantly greater quality across most vascular segments, including ICA (P = .019), M2 (P = .003), and M3 (P < .01). Superiority in the M1 segment approached significance (P = .059). Significantly better venographic quality was noted for deep venous structures (P = .016) with the use of blood-pool agents. Blood-pool agents provide superior demonstration of most intracranial vessels in time-resolved MRA compared with standard agents, at reduced doses. The greater relaxation enhancement and more favorable dosing profile make blood-pool agents superior to standard agents for use in cerebral time-resolved MRA.

Prognostic Evaluation Based on Cortical Vein Score Difference in Stroke

Multimodal imaging in acute ischemic stroke defines the extent of arterial collaterals, resultant penumbra, and associated infarct core, yet limitations abound. We identified superficial and deep venous drainage patterns that predict outcomes in patients with a proximal arterial occlusion of the anterior circulation. An observational study that used computed tomography (CT) angiography to detail venous drainage in a consecutive series of patients with a proximal anterior circulation arterial occlusion. The principal veins that drain the cortex (superficial middle cerebral, vein of Trolard, vein of Labbé, and basal vein of Rosenthal) and deep structures were scored with a categorical scale on the basis of degree of contrast enhancement. The Prognostic Evaluation based on Cortical vein score difference In Stroke score encompassing the interhemispheric difference of the composite scores of the veins draining the cortices (superficial middle cerebral+vein of Trolard+vein of Labbé+basal vein of Rosenthal) was analyzed with respect to 90-day modified Rankin Scale outcomes. Thirty-nine patients were included in the study. A Prognostic Evaluation based on Cortical vein score difference In Stroke score of 4 to 8 accurately predicted poor outcomes (modified Rankin Scale, 3-6; odds ratio, 20.53; P<0.001). On stepwise logistic regression analyses adjusted for CT Alberta stroke program early CT score, CT angiography collateral grading and National Institutes of Health Stroke Scale score, a Prognostic Evaluation based on Cortical vein score difference In Stroke score of 4 to 8 (odds ratio, 23.598; P=0.009) and an elevated admission National Institutes of Health Stroke Scale (odds ratio, 1.423; P=0.023) were independent predictors of poor outcome. The Prognostic Evaluation based on Cortical vein score difference In Stroke score, a novel measure of venous enhancement on CT angiography, accurately predicts clinical outcomes. Venous features on computed tomography angiography provide additional characterization of collateral perfusion and prognostication in acute ischemic stroke.

Subtracted 3D CT angiography for the evaluation of intracranial aneurysms in 256-slice multidetector CT: usefulness of the 80-kVp plus compact contrast medium bolus protocol

To evaluate the usefulness of an 80-kVp and compact contrast material protocol for arterial phase subtracted cerebral 3D-CTA using 256-slice multidetector CT. Thirty-two patients underwent CT with 100 kVp and received a contrast dose of 370 mgI/kg body weight over 15 s (protocol A). Thirty-three patients underwent CT with 100 kVp and received a contrast dose of 296 mgI/kg body weight over 10 s (protocol B). Thirty-three other patients underwent CT with 80 kVp and received a contrast medium dose of 296 mgI/kg body weight over 10 s (protocol C). We compared the arterial attenuation and contrast noise ratio (CNR) of each protocol. Two independent readers assessed overall image quality. Arterial attenuation was significantly higher under protocols A (418.6 ± 71.1 HU) and C (442.7 ± 79.3 HU) than under protocol B (355.8 ± 107.2 HU; P < 0.05). The CNR of protocol C (26.1 ± 6.1) was higher than that of protocol A (20.7 ± 8.4; P < 0.05). The overall image quality of protocol A was higher than that of protocol C (P < 0.01). The 80-kVp plus compact contrast protocol is well suited to arterial phase subtracted cerebral 3D-CTA without confounding venous enhancement. • Subtracted 3D CT angiography is useful in the evaluation of intracranial aneurysms. • A compact contrast material protocol increased arterial attenuation without venous contamination. • Low-kVp CT compensated for the decreased amount of contrast medium. • An 80-kVp CT with a compact enhancement bolus provides good intracranial 3D-CT angiography.

Finger-vein network enhancement and segmentation

Recently, an emerging biometric recognition based on human finger-vein patterns has received considerable attention. Due to light attenuation in imaging finger tissues, the finger-vein imagery is often seriously degraded. This makes network-based finger-vein feature representation greatly difficult in practice. In order to obtain perfect finger-vein networks, in this paper, we propose a novel scheme for venous region enhancement and finger-vein network segmentation. First, a method aimed at scattering removal, directional filtering and false vein information suppression is put forward to effectively enhance finger-vein images. Then, to achieve the high-fidelity extraction of finger-vein networks in an automated manner, a matting-based segmentation approach is presented considering the variations of veins in intensity and diameter. Extensive experiments are finally conducted to validate the proposed method.