VEGF-A plasma levels are associated with microvascular obstruction in patients with ST-segment elevation myocardial infarction.

BACKGROUND: Microvascular obstruction (MVO) is associated with poor outcome after ST-segment elevation myocardial infarction (STEMI). Vascular endothelial growth factor-A (VEGF-A) is a vascular permeability inducer playing a key role in MVO pathogenesis. We aimed to assess whether VEGF-A levels are associated with MVO, when evaluated by magnetic resonance imaging (MRI) in STEMI patients. METHODS: The multicenter prospective PREGICA study included a CMR substudy with all consecutive patients with a first STEMI who had undergone cardiac MRI at baseline and at 6-month follow-up. Patients with initial TIMI flow >1 were excluded. VEGF-A levels were measured in blood samples drawn at inclusion. RESULTS: Between 2010 and 2017, 147 patients (mean age 57 ±â€¯10 years; 84% males) were included. MVO was present in 65 (44%) patients. After multivariate analysis, higher troponin peak (OR 1.005; 95% CI 1.001-1.008; p = 0.007) and VEGF-A levels (OR 1.003; 95% CI 1.001-1.005; p = 0.015) were independently associated with MVO. When considering only patients with successful percutaneous coronary intervention (final TIMI flow 3, n = 130), higher troponin peak (p = 0.004) and VEGF-A levels (p = 0.03) remained independently predictive of MVO. Moreover, MVO was associated with adverse left ventricular (LV) remodeling and VEGF-A levels were significantly and inversely correlated with LV ejection fraction (EF) at 6-month follow-up. CONCLUSION: Our results show that VEGF-A levels were independently associated with MVO during STEMI and correlated with mid-term LVEF alteration. VEGF-A could therefore be considered as a biomarker of MVO in STEMI patients and be used to stratify patient prognosis.

Diffusion-weighted MR imaging of uterine leiomyomas following uterine artery embolization.

PURPOSE: To test whether variations in apparent diffusion coefficient (ADC) values of uterine leiomyomas after uterine artery embolization (UAE) may correlate with outcome and assess the effects of UAE on leiomyomas and normal myometrium with magnetic resonance imaging (MRI). METHODS: Data of 49 women who underwent pelvic MRI before and after UAE were retrospectively reviewed. Uterine and leiomyoma volumes, ADC values of leiomyomas, and normal myometrium were calculated before and after UAE. RESULTS: By comparison with baseline ADC values, a significant drop in leiomyoma ADC was found at 6-month post-UAE (1.096 × 10(-3) mm(2)/s vs. 0.712 × 10(-3) mm(2)/s, respectively; p < 0.0001), but not at 48-h post-UAE. Leiomyoma devascularization was complete in 40/49 women (82 %) at 48 h and in 37/49 women (76 %) at 6 months. Volume reduction and leiomyoma ADC values at 6 months correlated with the degree of devascularization. There was a significant drop in myometrium ADC after UAE. Perfusion defect of the myometrium was observed at 48 h in 14/49 women (28.5 %) in association with higher degrees of leiomyoma devascularization. CONCLUSION: Six months after UAE, drop in leiomyoma ADC values and volume reduction correlate with the degree of leiomyoma devascularization. UAE affects the myometrium as evidenced by a drop in ADC values and initial myometrial perfusion defect. KEY POINTS: • A drop in leiomyoma ADC values is observed 6 months after UAE. • Drop in leiomyoma ADC value is associated with leiomyoma devascularizarion after UAE. • MR 48 h post-UAE allows assessing leiomyoma devascularization. • Myometrium perfusion defect occurs more often in women with a smaller uterus.

Transcatheter Arterial Embolization for Postpartum Hemorrhage: Indications, Technique, Results, and Complications.

Postpartum hemorrhage (PPH) is a potentially life-threatening condition, which needs multidisciplinary management. Uterine atony represents up to 80 % of all causes of PPH. Transcatheter arterial embolization (TAE) has now a well-established role in the management of severe PPH. TAE allows stopping the bleeding in 90 % of women with severe PHH, obviating surgery. Pledgets of gelatin sponge as torpedoes are commonly used for safe TAE, and coils, glue, and microspheres have been primarily used in specific situations such as arterial rupture, pseudoaneurysm, and arteriovenous fistula. TAE is a minimally invasive procedure with a low rate of complications, which preserves future fertility. Knowledge of causes of PPH, potential risks, and limitations of TAE is essential for a timely decision, optimizing TAE, preventing irreversible complications, avoiding hysterectomy, and ultimately preserving fertility.

Role and Effectiveness of Percutaneous Arterial Embolization in Hemodynamically Unstable Patients with Ruptured Splanchnic Artery Pseudoaneurysms.

PURPOSE: To assess the role and effectiveness of percutaneous arterial embolization (TAE) in patients with hemodynamic instability due to hypovolemic shock secondary to ruptured splanchnic artery pseudoaneurysms (SAPA). MATERIALS AND METHODS: Seventeen patients (11 men, 6 women; mean age, 53 years) with hemodynamic instability (systolic blood pressure <90 mmHg) due to hypovolemic shock secondary to ruptured SAPA were treated by TAE. Clinical files, multidetector row computed tomography angiography, and angiographic examinations along with procedure details were reviewed. RESULTS: Seventeen SAPAs were present, predominantly located on gastroduodenal or pancreatic arteries (9/17; 53%). Angiography showed extravasation of contrast medium from SAPA in 15/17 patients (88%). Technical success rate of TAE was 100%. TAE was performed using metallic coils in all patients (100%), in association with gelatin sponge in 5/17 patients (29%). TAE allowed controlling the bleeding and returning to normal hemodynamic status in 16/17 patients (94%). In 1/17 patient (6%), surgery was needed to definitively control the bleeding. The mortality and morbidity rate of TAE at 30 days were 0 and 12%, respectively. Morbidity consisted in coil migration in 1/17 patient (6%) and transient serum liver enzyme elevation in 1/17 patient (6%). CONCLUSION: TAE is an effective and safe treatment option for ruptured SAPA in hemodynamically unstable patients, with a success rate of 94%. Our results suggest that TAE should be the favored option in patients with hemodynamic instability due to ruptured SAPA.

Postpartum hemorrhage resulting from pelvic pseudoaneurysm: a retrospective analysis of 588 consecutive cases treated by arterial embolization.

OBJECTIVE: This study was designed to determine the incidence of arterial pseudoaneurysm in patients presenting with postpartum hemorrhage (PPH), to analyze the angiographic characteristics of pseudoaneurysms that cause PPH, and to evaluate the effectiveness of pelvic arterial embolization for the treatment of this condition. STUDY DESIGN: Eighteen women with pelvic arterial pseudoaneurysm were retrieved from a series of 588 consecutive patients with PPH treated by arterial embolization. Clinical files, angiographic examinations, and procedure details were reviewed. RESULTS: The incidence of pseudoaneurysm was 3.06 % (18/588; 95 % confidence interval (CI): 1.82-4.8 %). A total of 20 pseudoaneurysms were found; 15/20 (75 %) were located on the uterine arteries. Angiography revealed extravasation of contrast material from pseudoaneurysm indicating rupture in 9 of 18 (50 %) patients. Arterial embolization was performed using gelatin sponge alone in 12 of 18 (67 %) patients or in association with metallic coils in 5 of 18 (28 %) patients or n-butyl-2-cyanoacrylate in 1 of 18 (6 %) patients. Arterial embolization allowed controlling the bleeding in all patients after one or two embolization sessions in 17 of 18 (94 %) and 1 of 18 patients (6 %) respectively, without complications, obviating the need for further surgery. CONCLUSIONS: Pseudoaneurysm is rarely associated with PPH. Arterial embolization is an effective and safe procedure for the treatment of PPH due to uterine or vaginal artery pseudoaneurysm. Our results suggest that gelatin sponge is effective for the treatment of ruptured pseudoaneurysms, although we agree that our series does not contain sufficient material to allow drawing definitive conclusions with respect to the most effective embolic material.

Colon cancer: comprehensive evaluation with 64-section CT colonography using water enema as intraluminal contrast agent-a pictorial review.

Sixty-four-section CT colonography with water enema combines intracolonic neutral contrast agent with high-resolution CT images of the abdomen. Owing to submillimeter isotropic voxels, high-quality reformatted images are obtained. High-resolution images offer added value for the detection and localization of colonic lesions, evaluation of the local extent of the disease, and depiction, if any, of synchronous colorectal lesions and distant metastases. Sixty-four-section CT colonography with water enema has a major role in the evaluation of patients with colon cancer before planning therapy. It can be used to complement failed or incomplete colonoscopy and investigate the colon in elderly patients.

Detection of colorectal tumors with water enema-multidetector row computed tomography.

PURPOSE: To retrospectively determine the diagnostic capabilities of water enema-multidetector row computed tomography (WE-MDCT) in the detection of colorectal tumors. MATERIALS AND METHODS: One hundred and one patients (55 male, 46 female) who had WE-MDCT and videocolonoscopy because of suspected colorectal tumors were included. Results of complete videocolonoscopy, surgery, and histopathologic analysis were used as standard of reference. Sensitivity, specificity, and accuracy, and positive and negative predictive values of WE-MDCT for the diagnosis of colorectal tumors were estimated with 95% confidence intervals (CIs). RESULTS: Ninety-two colorectal tumors (64 malignant, 28 benign) were confirmed in 71 patients (prevalence, 71/101; 70%). Overall sensitivity for colorectal tumor detection was 87% (80/92; 95%CI: 78%-93%) on a per lesion basis. For malignant and benign tumor detection, sensitivity was 100% (64/64; 95%CI: 94%-100%) and 57% (16/28; 95%CI: 37%-76%), respectively. For colorectal tumors ≥10 mm, sensitivity was 99% (76/77; 95%CI: 93%-100%). Seventy-nine of the 83 colorectal tumors ≥6 mm were detected, yielding a sensitivity of 95% (79/83; 95%CI: 88%-99%) for this specific size category. On a per patient basis, WE-MDCT had a sensitivity of 100% (71/71; 95%CI: 94%-100%), a specificity of 100% (30/30; 95%CI: 88%-100%), an accuracy of 100% (101/101; 95%CI: 96%-100%), a positive predictive value of 100% (71/71; 95%CI: 94%-100%), and a negative predictive value of 100% (30/30; 95%CI: 86%-100%) for the diagnosis of colorectal tumor. CONCLUSION: Our results suggest that WE-MDCT is a promising imaging technique for the detection of malignant colorectal tumors. However, our results should be validated by larger and prospective studies.

Differentiation between cavernous hemangiomas and untreated malignant neoplasms of the liver with free-breathing diffusion-weighted MR imaging: comparison with T2-weighted fast spin-echo MR imaging.

OBJECTIVE: To test interobserver variability of ADC measurements and compare the diagnostic performances of free-breathing diffusion-weighted (FBDW) with that of T2-weighted FSE (T2WFSE) MR imaging for differentiating between cavernous hemangiomas and untreated malignant hepatic neoplasms. MATERIALS AND METHODS: Thirty-five patients with cavernous hemangiomas and 35 with untreated hepatic malignant neoplasms had FBDW and T2WFSE MR imaging. Hepatic lesions were characterized with ADC measurement and visual evaluation. Interobserver agreement for ADC measurement was calculated. Association between ADC value and lesion type was assessed using univariate analysis. Sensitivity, specificity and accuracy of ADC values and visual evaluation of MR images for the diagnosis of untreated malignant hepatic neoplasm were compared. RESULTS: ADC measurements showed excellent interobserver correlation (intraclass correlation coefficient=0.980). Malignant neoplasms had lower ADC values than hemangiomas for the two observers (1.11×10(-3) mm2/s±.21×10(-3) vs. 1.77×10(-3) mm2/s±.29×10(-3) for observer 1 and 1.11×10(-3) mm2/s±.19×10(-3) vs. 1.79×10(-3) mm2/s±.32×10(-3) for observer 2) and univariate analysis found significant correlations between lesion type and ADC values. Depending on ADC threshold value, accuracy for the diagnosis of malignant neoplasm varied from 82.9% to 94.3%. Using visual evaluation, FBDW showed better specificity and accuracy than T2WFSE MR images for the diagnosis of malignant neoplasm (97.1% vs. 77.1% and 94.3% vs. 62.9%, respectively). CONCLUSION: FBDW imaging provides reproducible quantitative information and surpasses the value of T2WFSE MR imaging for differentiating between cavernous hemangiomas and untreated malignant hepatic neoplasms.

Preoperative detection of hepatic metastases: comparison of diffusion-weighted, T2-weighted fast spin echo and gadolinium-enhanced MR imaging using surgical and histopathologic findings as standard of reference.

PURPOSE: The purpose of this study was to retrospectively compare the respective sensitivities of diffusion-weighted (DW), T2-weighted fast spin-echo (T2WFSE) and gadolinium chelate-enhanced MR imaging in the preoperative detection of hepatic metastases using intraoperative ultrasonographic and histopathologic findings as the standard of reference. MATERIALS AND METHODS: Twenty-seven patients with 64 surgically and histopathologically proven hepatic metastases had MR imaging of the liver, including DW, T2WFSE and dynamic gadolinium chelate-enhanced MR imaging. Images from each MR sequence were separately analyzed by two readers with disagreements resolved by consensus readings. The findings on MR images were compared with intraoperative ultrasonographic and histopathologic findings on a lesion-by-lesion basis to determine the sensitivity of each MR sequence. Statistical review of the lesion-by-lesion analysis was performed with the McNemar test. RESULTS: DW, T2WFSE and gadolinium chelate-enhanced MR imaging allowed the depiction of 54/64 (84.4%; 95% CI: 73.1-92.2%), 44/64 (68.8%; 95% CI: 55.9-79.8%), and 51/64 (79.7%; 95% CI: 67.8-88.7%) hepatic metastases respectively. DW MR images allowed depiction of significantly more hepatic metastases than did T2WFSE and was equivalent to gadolinium chelate-enhanced MR imaging (P=.002 and P=.375, respectively). CONCLUSION: DW MR imaging is superior to T2WFSE imaging and equivalent to gadolinium chelate-enhanced MR imaging for the preoperative detection of hepatic metastases. Further studies however are needed to determine at what extent DW MR imaging can be used as an alternative to gadolinium chelate-enhanced MR imaging for the preoperative depiction of hepatic metastases.

Suspected anastomotic recurrence of Crohn disease after ileocolic resection: evaluation with CT enteroclysis.

PURPOSE: To determine the utility of computed tomographic (CT) enteroclysis for characterization of the status of the anastomotic site in patients with Crohn disease who had previously undergone ileocolic resection. MATERIALS AND METHODS: Written informed consent was prospectively obtained from all patients, and the institutional review board approved the study protocol. CT enteroclysis findings in 40 patients with Crohn disease who had previously undergone ileocolic resection were evaluated independently by two readers. Endoscopic findings, histopathologic findings, and/or the Crohn disease activity index was the reference standard. Interobserver agreement between the two readers was calculated with kappa statistics. Associations between CT enteroclysis findings and anastomotic site status were assessed at univariate analysis. The sensitivity, specificity, and accuracy of CT enteroclysis, with corresponding 95% confidence intervals (CIs), for the diagnosis of normal versus abnormal anastomosis and the diagnosis of anastomotic recurrence versus fibrostenosis were estimated. RESULTS: Interobserver agreement regarding CT enteroclysis criteria was good to perfect (kappa = 0.72-1.00). At univariate analysis, stratification and anastomotic wall thickening were the two most discriminating variables in the differentiation between normal and abnormal anastomoses (P < .001). Stratification (P < .001) and the comb sign (P = .026) were the two most discriminating variables in the differentiation between anastomotic recurrence and fibrostenosis. In the diagnosis of anastomotic recurrence, severe anastomotic stenosis was the most sensitive finding (95% [20 of 21 patients]; 95% CI: 76.18%, 99.88%), both comb sign and stratification had 95% specificity (18 of 19 patients; 95% CI: 73.97%, 99.87%), and stratification was the most accurate finding (92% [37 of 40 patients]; 95% CI: 79.61%, 98.43%). In the diagnosis of fibrostenosis, both severe anastomotic stenosis and anastomotic wall thickening were 100% sensitive (eight of eight patients; 95% CI: 63.06%, 100.00%), and using an association among five categorical variables, including severe anastomotic stenosis, anastomotic wall thickening with normal or mild mucosal enhancement, absence of comb sign, and absence of fistula, yielded 88% sensitivity (seven of eight patients; 95% CI: 47.35%, 99.68%), 97% specificity (31 of 32 patients; 95% CI: 83.78%, 99.92%), and 95% accuracy (38 of 40 patients; 95% CI: 83.08%, 99.39%). CONCLUSION: CT enteroclysis yields objective and relatively specific morphologic criteria that help differentiate between recurrent disease and fibrostenosis at the anastomotic site after ileocolic resection for Crohn disease. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.09091165/-/DC1.

Free-breathing diffusion-weighted single-shot echo-planar MR imaging using parallel imaging (GRAPPA 2) and high b value for the detection of primary rectal adenocarcinoma.

Our objective was to determine the diagnostic accuracy of a free-breathing diffusion-weighted single-shot echo-planar magnetic resonance imaging (FBDW-SSEPI) technique with parallel imaging and high diffusion factor value (b = 1000 s/mm2) in the detection of primary rectal adenocarcinomas. Thirty-one patients (14M and 17F; mean age 67 years) with histopathologically proven primary rectal adenocarcinomas and 31 patients without rectal malignancies (14M and 17F; mean age 63.6 years) were examined with FBDW-SSEPI (repetition time (TR/echo time (TE) 3900/91 ms, gradient strength 45 mT/m, acquisition time 2 min) at 1.5 T using generalized autocalibrating partially parallel acquisitions (GRAPPA, acceleration factor 2) and a b value of 1000 s/mm2. Apparent diffusion coefficients (ADCs) of rectal adenocarcinomas and normal rectal wall were measured. FBDW-SSEPI images were evaluated for tumour detection by 2 readers. Sensitivity, specificity, accuracy and Youden score for rectal adenocarcinoma detection were calculated with their 95% confidence intervals (CI) for ADC value measurement and visual image analysis. Rectal adenocarcinomas had significantly lower ADCs (mean 1.036 x 10(-3)+/- 0.107 x 10(-3) mm2/s; median 1.015 x 10(-3) mm2/s; range (0.827-1.239) x 10(-3) mm2/s) compared with the rectal wall of control subjects (mean 1.387 x 10(-3)+/- 0.106 x 10(-3) mm2/s; median 1.385 x 10(-3) mm2/s; range (1.176-1.612) x 10(-3) mm2/s) (p < 0.0001). Using a threshold value < or = 1.240 x 10(-3) mm2/s, all rectal adenocarcinomas were correctly categorized and 100% sensitivity (31/31; 95% CI 95-100%), 94% specificity (31/33; 95% CI 88-100%), 97% accuracy (60/62; 95% CI 92-100%) and Youden index 0.94 were obtained for the diagnosis of rectal adenocarcinoma. FBDW-SSEPI image analysis allowed depiction of all rectal adenocarcinomas but resulted in 2 false-positive findings, yielding 100% sensitivity (31/31; 95% CI 95-100%), 94% specificity (31/33; 95% CI 88-100%), 97% accuracy (60/62; 95% CI 92-100%) and Youden index 0.94 for the diagnosis of primary rectal adenocarcinoma. We can conclude that FBDW-SSEPI using parallel imaging and high b value may be helpful in the detection of primary rectal adenocarcinomas.

Differentiation between true focal liver lesions and pseudolesions in patients with fatty liver: evaluation of helical CT criteria.

OBJECTIVE: To determine the potential of helical CT for differentiating true lesions from pseudolesions in patients with fatty liver. METHODS: Helical CT of 44 patients with diffuse fatty liver (22 with true lesions; 22 with pseudolesions) were reviewed by two observers with regard to morphological features of visible lesions. Univariate analysis was used to detect discriminating criteria for the diagnosis of true lesions. RESULTS: Interobserver agreement was excellent for 9/10 morphological criteria (kappa = 0.831-1). True lesions were more frequently distant from the liver capsule (50.00% vs. 4.55%), located in the right lobe (72.73% vs. 31.82%), round (86.36% vs. 54.55%), heterogeneous (27.27% vs. 0.00%) and had ill-defined margins (40.91% vs. 13.64%) compared with pseudolesions (P < 0.05). Using univariate analysis, a location distant from the liver capsule was the most discriminating variable to differentiate between true and pseudolesions (P = 0.0060). Hyperattenuating content and round shape were the most sensitive criteria (sensitivity = 90.91% and 86.36%, respectively) for the diagnosis of true lesions, and heterogeneity, vascular displacement and encapsulation were the three most specific ones (specificity = 100.00%). Best accuracy was obtained with an association of the three variables (accuracy = 86.36%). CONCLUSION: Helical CT provides objective and discriminating morphological criteria to differentiate between true lesions and pseudolesions in patients with fatty liver.

Crohn's disease: multi-detector row CT-enteroclysis appearance of the appendix.

The objective of our retrospective study was to determine the MDCT-enteroclysis appearance of the appendix in patients with Crohn's disease and to correlate this appearance with the status of the disease. We reviewed the MDCT-enteroclysis examinations of 76 patients with Crohn's disease. Images were analyzed for visualization of the appendix, largest axial diameter of the appendix and degrees of enhancement. Findings were correlated with the status of the disease (active vs. nonactive) and compared with those observed in a control group. Among the various variables, hyperenhancement of the appendiceal wall was found in 18.9% of patients with active disease and in no patients with inactive disease nor in the control group (P = 0.0023). This sign had a specificity of 100% for differentiating between active and inactive Crohn's disease. We conclude that increased appendiceal wall enhancement is, at a statistically significant level, more frequently observed in patients with active Crohn's disease by comparison with patients with inactive disease and control subjects. This result suggests that this finding may be used as an additional MDCT-enteroclysis finding to determine the activity of the disease.

Life-threatening intra-abdominal hemorrhage from left superior colonic artery pseudoaneurysm after percutaneous renal biopsy: successful treatment with superselective arterial embolization.

Life-threatening intra-abdominal hemorrhage following ultrasonographically guided percutaneous renal biopsy is extremely rare and, most of the time, is due to renal vascular injury. Injury of other abdominal arteries during percutaneous renal biopsy is exceedingly rare. We report herein a case of left superior colonic artery injury during ultrasonographically guided percutaneous renal biopsy, which was responsible for pseudoaneurysm formation and subsequent intra-abdominal hemorrhage and gastrointestinal bleeding. Arterial pseudoaneurysm was rapidly and successfully treated with minimally invasive endovascular treatment using microcoils. Superselective embolization stopped the bleeding and preserved colonic vascularization, thus preventing ischemia of the involved colonic segment.

Increased neovascularization in advanced lipid-rich atherosclerotic lesions detected by gadofluorine-M-enhanced MRI: implications for plaque vulnerability.

BACKGROUND: Inflammation and neovascularization may play a significant role in atherosclerotic plaque progression and rupture. We evaluated gadofluorine-M-enhanced MRI for detection of plaque inflammation and neovascularization in an animal model of atherosclerosis. METHODS AND RESULTS: Sixteen rabbits with aortic plaque and 6 normal control rabbits underwent gadofluorine-M-enhanced MRI. Eight rabbits had advanced atherosclerotic lesions, whereas the remaining 8 had early lesions. Magnetic resonance atherosclerotic plaque enhancement was meticulously compared with plaque inflammation and neovessel density as assessed by histopathology. Advanced plaques and early atheroma were enhanced after gadofluorine-M injection. Control animals displayed no enhancement. After accounting for the within-animal correlation of observations, mean contrast-to-noise ratio was significantly higher in advanced plaques than compared with early atheroma (4.29+/-0.21 versus 3.00+/-0.32; P=0.004). Macrophage density was higher in advanced plaques in comparison to early atheroma (geometric mean=0.50 [95% CI, 0.19 to 1.03] versus 0.25 [0.07 to 0.42]; P=0.05). Furthermore, higher neovessel density was observed in advanced plaques (1.83 [95% CI, 1.51 to 2.21] versus 1.29 [0.99 to 1.69]; P=0.05). The plaque accumulation of gadofluorine-M correlated with increased neovessel density as shown by linear regression analysis (r=0.67; P<0.001). Confocal and fluorescence microscopy revealed colocalization of gadofluorine-M with plaque areas containing a high density of neovessels. CONCLUSIONS: Gadofluorine-M-enhanced MRI is effective for in vivo detection of atherosclerotic plaque inflammation and neovascularization in an animal model of atherosclerosis. These findings suggest that gadofluorine-M enhancement reflects the presence of high-risk plaque features believed to be associated with plaque rupture. Gadofluorine-M plaque enhancement may therefore provide functional assessment of atherosclerotic plaque in vivo.

Radiation dose and cancer risk estimates in 16-slice computed tomography coronary angiography.

BACKGROUND: Recent advances have led to a rapid increase in the number of computed tomography coronary angiography (CTCA) studies performed. Whereas several studies have reported the effective dose, there are no data available on cancer risk for current CTCA protocols. METHODS AND RESULTS: Effective and organ doses were estimated, by use of scanner-derived parameters and Monte Carlo methods, for 50 patients having 16-slice CTCA performed for clinical indications. Lifetime attributable risks were estimated with models developed in the National Academies' Biological Effects of Ionizing Radiation VII report. The effective dose of a complete CTCA averaged 9.5 mSv, whereas that of a complete study, including calcium scoring when indicated, averaged 11.7 mSv. Calcium scoring increased effective dose by 25%, whereas tube current modulation reduced it by 34% and was more effective at lower heart rates. Organ doses to the lungs and female breast were highest. The lifetime attributable risk of cancer incidence from CTCA averaged approximately 1 in 1,600 but varied widely among patients, being highest in younger women. For all patients, the greatest risk was from lung cancer. CONCLUSIONS: CTCA is associated with non-negligible risk of malignancy. Doses can be reduced by careful attention to scanning protocol.

Chronic thrombus detection with in vivo magnetic resonance imaging and a fibrin-targeted contrast agent.

BACKGROUND: Arterial thrombosis plays a critical role in acute coronary syndromes and stroke. Therefore, the ability to detect thrombus in vivo has a significant clinical implication. Magnetic resonance imaging (MRI) has shown promise in noninvasive thrombus detection. However, thrombus characterization and age definition remain difficult. We sought to evaluate the use of a fibrin-targeted peptide (EP-2104R) for MR thrombus detection and to compare this modality with non-contrast-enhanced (NCE) MRI and with Gd-DTPA injection at various ages and time points after thrombus generation. METHODS AND RESULTS: Carotid artery thrombosis was induced by external injury and stasis in 18 rabbits. T1-weighted MRI was performed before and after contrast agent injection, within 6 hours of thrombus induction, at 48 hours, at 1 week, and every week up to 8 weeks after injury. Correlation with histopathology was performed. The fibrin-targeted contrast agent accurately detected all thrombi, regardless of their size, location, and age. Although thrombus signal intensity after injection decreased with thrombus age (P<0.001), enhancement at 8 weeks was still present. Gd-DTPA injection was not associated with an improvement of thrombus detection. EP-2104R was superior to both NCE and Gd-DTPA injection (P<0.001). Histopathologic examination showed thrombus organization over time. Fibrin was gradually replaced by fibrous tissue. A strong correlation was found between thrombus enhancement and collagen content of the organizing thrombus with time (R=-0.89; P<0.001). CONCLUSIONS: In an experimental animal model of carotid thrombosis, we have demonstrated the superiority of a fibrin-targeted MR contrast agent for in vivo detection of chronic or organized thrombus, compared with NCE MRI and Gd-DTPA injection.