MR venography in patients with multiple sclerosis and correlation with clinical and MRI parameters.

BACKGROUND AND PURPOSE: Multiple sclerosis (MS) has been associated with chronic cerebrospinal venous insufficiency. We aim to evaluate the correlation between extracranial veins stenosis evaluated with MR venography (MRV) and clinical/MR parameters of MS. METHODS: In 29 consecutive MS patients we performed a standard brain MRI protocol, completed by the evaluation of extra-cerebral venous system using a phase-contrast and a Volumetric Interpolated Breath Hold Examination (VIBE) sequence before and after gadolinium. The T2-proton density images were used to calculate the lesion volume. The jugular veins were evaluated qualitatively (in terms of presence and severity of stenoses) and quantitatively (degree of stenosis). The phase-contrast images were analyzed to calculate the average and peak velocity in the internal jugular veins. RESULTS: Postcontrast VIBE successfully showed the jugular veins in all the subjects. T2-lesion-volume was 8.2 [4.6] cm³. A stenosis of the internal jugular veins > of 50% was observed in 10/29(33%) patients. No significant correlation was observed between T2-lesion-volume and degree-of-stenosis (r = .362, P = .302). No different flow parameters were found in the subgroups of patients with and without stenosis (P = .54). CONCLUSIONS: In MS the presence/severity of jugular vein stenosis identified with 3T-MRV is not related to MR-visible tissue damage. Moreover no abnormal flow parameters were found in stenosed veins.

Magnetic resonance-guided high-intensity focused ultrasound treatment of locally advanced pancreatic adenocarcinoma: preliminary experience for pain palliation and local tumor control.

PURPOSE: The purpose of this study was to evaluate the feasibility of magnetic resonance-guided focused ultrasound (MRgFUS) ablation for pain palliation and local tumor control in selected patients with unresectable primary pancreatic adenocarcinoma. MATERIALS AND METHODS: After providing dedicated informed consent, 7 patients with histologically proven unresectable pancreatic adenocarcinoma underwent MRgFUS treatment on a dedicated 3-T unit featuring a dedicated ablation system. All lesions were evaluated for device accessibility before the treatment. Procedures of MRgFUS were performed with the patients under general anesthesia with constant controlled respiration. Clinical assessment included evaluation of symptom severity using a visual analog scale before and after the treatment. Imaging follow-up, including both computed tomographic and magnetic resonance examinations, was performed immediately after the treatment and at 3 and 6 months to evaluate the effects of MRgFUS on the targeted tumor and the occurrence, if any, of procedure-related complications. RESULTS: The MRgFUS ablation was successfully performed in 6 patients; no adverse events were observed during or after the procedure. In a single patient, lesion accessibility was limited at treatment time, and the procedure was suspended. The visual analog scale score decreased in all patients from a mean (SD) of 7 (1) to 3 (1) after the treatment. Follow-up imaging results revealed negligible (n = 1) or no (n = 5) tumor regrowth within the ablation area. One patient died because of a metastatic disease 13 months after the treatment, whereas the other 5 are nonprogressing survivors at 6 and 8 months after the treatment. CONCLUSIONS: Our preliminary clinical experience suggests that MRgFUS is a feasible and repeatable ablative technique in selected patients with unresectable and device-accessible pancreatic adenocarcinoma.

Magnetic resonance-guided focused ultrasound ablation in abdominal moving organs: a feasibility study in selected cases of pancreatic and liver cancer.

PURPOSE: This study was designed to evaluate preliminarily the feasibility and safety of magnetic resonance-guided focused ultrasound (MRgFUS) for treatment of solid tumors in the upper abdomen. METHODS: We enrolled one patient with hepatocellular carcinoma and two patients with pancreatic adenocarcinoma for MRgFUS ablation. Treatments were performed on a 3T scanner under controlled respiration. Treatment response was evaluated at 1, 3, and 6 months by assessing the nonperfused volume (NPV) of ablated tissue at MR and the degree of pain severity and pain interference. RESULTS: In the patient with HCC, NPV was 100% after treatment and 85% at 3 and 6 months follow-up. Histological analysis after liver transplantation showed fibrosis in the ablated area with minimal local tumor recurrence. In the two patients with pancreatic adenocarcinoma, NPV was 80 and 85% after treatment and 70 and 80% at 3 and 6 months follow-up. Pain severity and pain interference respectively decreased from a mean of 7 and 6.7 points, respectively, to a mean of 3 and 2 points after treatment. CONCLUSIONS: MRgFUS can be feasible and safe in selected patients with solid tumors in abdominal moving organs. However, this technique has several limitations due to the interposition of the rib cage or intestinal loops into the path of the ultrasonic beam, as well as to organ motion. Future technical developments are needed to implement advanced motion detection within the system to control organ and lesion position in real-time and keep the focus of the ultrasound beam on the targeted lesion.

Imaging of the carotid artery vulnerable plaque.

Atherosclerosis involving the carotid arteries has a high prevalence in the population worldwide. This condition is significant because accidents of the carotid artery plaque are associated with the development of cerebrovascular events. For this reason, carotid atherosclerotic disease needs to be diagnosed and those determinants that are associated to an increased risk of stroke need to be identified. The degree of stenosis typically has been considered the parameter of choice to determine the therapeutical approach, but several recently published investigations have demonstrated that the degree of luminal stenosis is only an indirect indicator of the atherosclerotic process and that direct assessment of the plaque structure and composition may be key to predict the development of future cerebrovascular ischemic events. The concept of "vulnerable plaque" was born, referring to those plaque's parameters that concur to the instability of the plaque making it more prone to the rupture and distal embolization. The purpose of this review is to describe the imaging characteristics of "vulnerable carotid plaques."

MR imaging-guided focused ultrasound for treatment of bone metastasis.

Magnetic resonance (MR) imaging-guided focused ultrasound is an alternative noninvasive method for reducing the pain in skeletal metastases. MR imaging-guided focused ultrasound ablation offers several key advantages over other noninvasive treatment modalities. This technology enables the performance of three-dimensional treatment planning with MR imaging and continuous temperature mapping of treated tissue by using MR thermometry, thereby enabling real-time monitoring of thermal damage in the target zone. The concentration of acoustic energy on the intact surface of cortical bone produces a rapid temperature increase that mediates critical thermal damage to the adjacent periosteum, the most innervated component of mature bone tissue. Such thermal ablation has been shown to be an extremely effective approach for pain management. Energy delivered during MR imaging-guided focused ultrasound ablation and accumulated inside the pathologic soft tissue of the metastases can create a variable amount of tissue necrosis. This technique has also a potential role in achieving local tumor control, allowing remineralization of trabecular bone or reduction in lesion size. The current report presents a detailed step-by-step guide for performing MR imaging-guided focused ultrasound ablation of bone metastases, including use of MR thermometry for monitoring treatment, protocol selection for simple palliation of pain or for local tumor control, and a description of imaging features of periosteal neurolysis or metastasis ablation. Two case studies are also presented: in the first, the technique provided palliation of pain in bone metastases, and in the second, the technique achieved tumor control as further proof of primary efficacy. MR imaging-guided focused ultrasound ablation is a promising method for successful palliation of bone metastasis pain and tumor control, because of the bony structure remodeling induced by thermo-related coagulative necrosis.

Primary pain palliation and local tumor control in bone metastases treated with magnetic resonance-guided focused ultrasound.

OBJECTIVES: The objectives of this study were to evaluate the efficacy in pain management of magnetic resonance (MR)-guided focused ultrasound for the primary treatment of painful bone metastases and to assess its potential for local control of bone metastases. MATERIALS AND METHODS: This was a prospective, single-arm research study with approval from the institutional review board. Eighteen consecutive patients (female, 8; male, 10; mean [SD] age, 62.7 [11.5] years) with painful bone metastases were enrolled. The patients were examined clinically for pain severity and pain interference in accordance with the Brief Pain Inventory-Quality of Life criteria before and at each follow-up visit. Computed tomography and MR imaging were performed before and at 1 and 3 months after the magnetic resonance-guided focused ultrasound treatment. The nonperfused volume (NPV) was calculated to correlate the extension of the ablated pathological tissue in the responder and nonresponder patients. RESULTS: No treatment-related adverse events were recorded during the study. The evaluation of pain palliation revealed a statistically significant difference between baseline and follow-up values for pain severity and pain interference (P = 0.001, both evaluations). In the evaluation of local tumor control, we observed increased bone density with restoration of cortical borders in 5 of the 18 patients (27.7%). In accordance with the MD Anderson criteria, complete and partial responses were obtained in 2 of the 18 patients (11.1%) and 4 of the 18 patients (22.2%), respectively. Nonperfused volume values ranged between 20% and 93%. Mean NPV values remained substantially stable after the treatment (P = 0.08). There was no difference in the NPV values between the responder and nonresponder patients (46.7% [24.2%] [25%-90%] versus 45% [24.9%] [20%-93%]; P = 0.7). CONCLUSIONS: Magnetic resonance-guided focused ultrasound can be safely and effectively used as the primary treatment of pain palliation in patients with bone metastases and has a potential role in local tumor control.

Liver metastases from colorectal cancer treated with conventional and antiangiogenetic chemotherapy: evaluation with liver computed tomography perfusion and magnetic resonance diffusion-weighted imaging.

OBJECTIVE: The objectives of the study were to determine whether perfusion computed tomography (CT-p) and magnetic resonance diffusion-weighted imaging (MR-DWI) can allow evaluation of the effects of chemotherapy combined with antiangiogenetic treatment on liver metastases in patients with advanced colorectal cancer and to determine if changes in CT-p and MR-DWI correlate with the response to therapy as assessed by conventional Response Evaluation Criteria in Solid Tumors (RECIST). METHODS: Eighteen patients with liver metastases from colorectal cancer underwent CT-p and MR-DWI before and 6 months after chemotherapy and antiangiogenetic treatment. Lesions were classified according to RECIST criteria (complete response [CR], partial response [PR], stable disease [SD], and progressive disease) and calculations of CT-p parameters including blood flow (BF), blood volume (BV), capillary permeability (CP), and MR-DWI apparent diffusion coefficient (ADC) values were performed; RECIST, CT-p, and MR-DWI measurements at baseline and follow-up were tested for statistically significant differences using the paired-samples t test. Baseline and follow-up perfusion parameters of the lesions were also compared on the basis of therapy response assessed by RECIST criteria using independent-samples t test. P < 0.05 was considered indicative of a statistically significant difference for all statistical test. RESULTS: Six patients (6/18; 33.3%) were classified as PR (), and the remaining 12 (12/18; 66.7%) were classified as SD. On a per-lesion basis, 2 (2/32; 6.3%) cannot be identified at follow-up, 6 (6/32; 18.8%) showed a decrease in size of more than 30%, and 24 (24/32; 75%) were substantially stable in size. No cases of progressive disease were demonstrated at follow-up. No statistically significant differences were demonstrated between PR, CR, and SD lesions for BF (P = 0.19), BV (P = 0.14), and ADC (P = 0.68) measurements, whereas CP was significantly higher in CR and PR lesions (P = 0.038). Considering differences between baseline and follow-up values, no statistically significant differences were noted between PR and CR lesions versus SD lesions for CT-p values (BF: P = 0.77; BV: P = 0.15; CP: P = 0.64). A statistically significant difference between PR and CR lesions and SD lesions was noted for ADC values (P = 0.047). CONCLUSION: Both CT-p and MR-DWI can detect therapy-induced modifications in lesion vascularization before significant changes in size are evident.

The relationship between metabolic syndrome, its components, and the whole-body atherosclerotic disease burden as measured by computed tomography angiography.

OBJECTIVE: Quantify the whole-body atherosclerotic disease in asymptomatic subjects with and without metabolic syndrome (MetS) and to assess the contribution of the syndrome and its components to the atherosclerotic burden. METHODS: Sixty-five subjects with and 51 without ATPIII-defined MetS underwent a 64-slice computed tomography angiography (CTA). Plaques causing >0% stenosis in coronary or extra-coronary arteries were classified as positive. RESULTS: The prevalence of plaques in coronary, carotid and peripheral arteries as well as their severity did not differ between groups. Conversely, it was seen an almost 3-fold increased likelihood (OR=2.70; 95% CI 1.30-5.57; P<0.001) of atherosclerosis in any district across categories of MetS components (0-1 vs. 2-3 vs. 4-5). Hypertriglyceridemia (P<0.05) and high blood glucose (P<0.05) were independent predictors of the atherosclerotic burden. CONCLUSIONS: Atherosclerotic burden as revealed by 64-TCA appears to be more strongly associated with the number of MetS-related factors than to the clinical diagnosis of MetS itself.

High-resolution steady state magnetic resonance angiography of the carotid arteries: are intravascular agents necessary?: feasibility and preliminary experience with gadobenate dimeglumine.

PURPOSE: To prospectively evaluate the potential of gadobenate dimeglumine for high-resolution steady-state (SS) contrast-enhanced magnetic resonance angiography (CE-MRA) of the carotid arteries as an adjunct to conventional first-pass (FP) MRA, with computed tomography angiography (CTA) and digital subtraction angiography (DSA) as reference. MATERIALS AND METHODS: Institutional ethics committee approval and written informed consent were obtained. Forty consecutive patients underwent conventional FP MRA with 15 mL gadobenate dimeglumine, using a conventional 3D FLASH sequence (14 sec acquisition time). Immediately afterward, SS images were obtained using a high resolution coronal 3D FLASH sequence (240 sec acquisition time). All patients also underwent CTA and conventional DSA within 8 +/- 3 days. Three experienced radiologists assessed FP and SS image quality and calculated sensitivity, specificity, accuracy, and predictive values for stenosis grade and length, plaque morphology, and tandem lesions using DSA as reference. Detected stenoses were quantified and compared (Spearman rank correlation coefficient, [R(s)]; McNemar test) with DSA and CTA findings. Inter-read variability was assessed using kappa (kappa) statistics. The impact of SS acquisitions on diagnostic confidence and patient management was assessed. RESULTS: MRA FP and SS image quality was excellent in 63 (78.8%) and 46 (57.5%) vessels, adequate in 11 (13.8%) and 20 (25.0%) vessels, and poor in 6 (7.5%) and 14 (17.5%) vessels, respectively. Area under the curve analysis revealed no significant differences between MRA FP, MRA FP + SS, and CTA for the grading of stenoses (P = 0.838; accuracy values of 97.4%, 97.4%, and 98.7%, respectively). Greater accuracy (P < 0.001) was noted for FP + SS images over FP images alone for the assessment of plaque morphology (96.1% for FP + SS images vs. 83.3% for FP). Increased diagnostic confidence was noted for 49 (61.3%) vessels because of additional SS images whereas an impact on final diagnosis was noted in 8 (10%) cases. Good correlation was noted between SS image quality and impact on final diagnosis (R(s) = 0.7; P < 0.0001). CONCLUSION: SS imaging of the carotid arteries is feasible with gadobenate dimeglumine. The increased spatial resolution attainable allows improved evaluation of stenoses and plaque irregularity, yielding comparable diagnostic performance to that of CTA and DSA.

Gadofosveset-enhanced MR angiography of carotid arteries: does steady-state imaging improve accuracy of first-pass imaging? Comparison with selective digital subtraction angiography.

PURPOSE: To evaluate the diagnostic accuracy of gadofosveset-enhanced magnetic resonance (MR) angiography in the assessment of carotid artery stenosis, with digital subtraction angiography (DSA) as the reference standard, and to determine the value of reading first-pass, steady-state, and "combined" (first-pass plus steady-state) MR angiograms. MATERIALS AND METHODS: This study was approved by the local ethics committee, and all subjects gave written informed consent. MR angiography and DSA were performed in 84 patients (56 men, 28 women; age range, 61-76 years) with carotid artery stenosis at Doppler ultrasonography. Three readers reviewed the first-pass, steady-state, and combined MR data sets, and one independent observer evaluated the DSA images to assess stenosis degree, plaque morphology and ulceration, stenosis length, and tandem lesions. Interobserver agreement regarding MR angiographic findings was analyzed by using intraclass correlation and Cohen kappa coefficients. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated by using the McNemar test to determine possible significant differences (P < .05). RESULTS: Interobserver agreement regarding all MR angiogram readings was substantial. For grading stenosis, sensitivity, specificity, PPV, and NPV were, respectively, 90%, 92%, 91%, and 91% for first-pass imaging; 95% each for steady-state imaging; and 96%, 99%, 99%, and 97% for combined imaging. For evaluation of plaque morphology, respective values were 84%, 86%, 88%, and 82% for first-pass imaging; 98%, 97%, 98%, and 97% for steady-state imaging; and 98%, 100%, 100%, and 97% for combined imaging. Differences between the first-pass, steady-state, and combined image readings for assessment of stenosis degree and plaque morphology were significant (P < .001). CONCLUSION: Gadofosveset-enhanced MR angiography is a promising technique for imaging carotid artery stenosis. Steady-state image reading is superior to first-pass image reading, but the combined reading protocol is more accurate.

Imaging coronary and extracoronary atherosclerosis: feasibility and impact of whole-body computed tomography angiography.

A comprehensive whole-body approach to noninvasive evaluation of coronary and extracoronary vasculature is currently not available. The objective of our study was to assess the potential of 64-slice computed tomography angiography (64-CTA) for whole-body evaluation of atherosclerosis burden. Seventy-eight patients referred for coronary imaging underwent whole-body 64-CTA using an adjusted strategy for the administration of contrast medium with dose-saving algorithms involving ECG modulation and reduced tube voltage. Arterial segments (15 coronary, 32 systemic) were evaluated for significant (> or =50%) steno-occlusive disease while arterovenous density was evaluated at seven extracoronary locations. Homogeneous attenuation (mean 321 +/- 20 HU) was obtained throughout the systemic vasculature. Atherosclerosis was observed in 238/995 (24%) coronary and 368/2441 (15%) systemic segments. Significant stenoses/occlusions were present in 214 (21%)/24 (2.5%) coronary segments while asymptomatic clinically relevant stenoses were present in 49 systemic segments. Sensitivity, specificity, positive and negative predictive values of coronary 64-CTA among 52 patients who also underwent quantitative coronary angiography were 92%, 95%, 81% and 98%, respectively. ECG modulation decreased radiation exposure to 14.1-15.4 mSv per patient. Comprehensive, noninvasive assessment of atherosclerosis can be performed by whole-body 64-CTA and may have a positive impact on secondary prevention.