Positive Enhancement Integral Research Articles

Dynamic Contrast-Enhanced and Diffusion-Weighted Magnetic Resonance Imaging Noninvasive Evaluation of Vascular Disrupting Treatment on Rabbit Liver Tumors

Evaluation of vascular disrupting treatment (VDT) is generally based on tumor size and enhancement on conventional magnetic resonance imaging (MRI) which, unfortunately, may be limited in providing satisfactory information. The purpose of the study is to evaluate consecutive changes of 20 rabbit VX2 liver tumors after VDT by dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) at a 3.0 T MR unit. Twenty four hours after intravenous injection of Combretastatin A-4-phosphate (CA4P) at 20 mg/kg, DCE-MRI derived Maximum Slope of Increase (MSI) and Positive Enhancement Integral (PEI) decreased sharply due to sudden shutting down of tumor feeding vessels. DWI derived Apparent Diffusion Coefficient (ADC) in tumor periphery decreased because of ischemic cell edema. On day 4, an increase of MSI was probably caused by the recovery of blood supply. A remarkable increase of ADC represented a large scale of necrosis among tumors. On day 8, the blood perfusion further decreased and the extent of necrosis further increased, reflected by lower MSI and PEI values and higher ADC value. On day 12, a second decrease of ADC was noticed because the re-growth of periphery tumor. The experimental data indicate that the therapeutic effects of VDT may be noninvasively monitored with DCE-MRI (reflecting tumor blood perfusion) and DWI (reflecting the changes of histology), which provide powerful measures for assessment of anticancer treatments.

Spleen Dynamic Contrast-Enhanced Magnetic Resonance Imaging as a New Method for Staging Liver Fibrosis in a Piglet Model

ObjectiveTo explore spleen hemodynamic alteration in liver fibrosis with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and to determine how to stage liver fibrosis with spleen DCE-MRI parameters.Materials and MethodsSixteen piglets were prospectively used to model liver fibrosis staged by liver biopsy, and underwent spleen DCE-MRI on 0, 5th, 9th, 16th and 21st weekend after modeling this disease. DCE-MRI parameters including time to peak (TTP), positive enhancement integral (PEI), maximum slope of increase (MSI) and maximum slope of decrease (MSD) of spleen were measured, and statistically analyzed to stage this disease.ResultsSpearman's rank correlation tests showed that TTP tended to increase with increasing stages of liver fibrosis (r = 0.647, P<0.001), and that PEI tended to decrease from stage 0 to 4 (r = −0.709, P<0.001). MSD increased slightly from stage 0 to 2 (P>0.05), and decreased from stage 2 to 4 (P<0.05). MSI increased from stage 0 to 1, and decreased from stage 1 to 4 (all P>0.05). Mann-Whitney tests demonstrated that TTP and PEI could classify fibrosis between stage 0 and 1–4, between 0–1 and 2–4, between 0–2 and 3–4, or between 0–3 and 4 (all P<0.01). MSD could discriminate between 0–2 and 3–4 (P = 0.006), or between 0–3 and 4 (P = 0.012). MSI could not differentiate between any two stages. Receiver operating characteristic analysis illustrated that area under receiver operating characteristic curve (AUC) of TTP was larger than of PEI for classifying stage ≥1 and ≥2 (AUC = 0.851 and 0.783, respectively). PEI could best classify stage ≥3 and 4 (AUC = 0.903 and 0.96, respectively).ConclusionSpleen DCE-MRI has potential to monitor spleen hemodynamic alteration and classify liver fibrosis stages.

Liver dynamic contrast‐enhanced MRI for staging liver fibrosis in a piglet model

To determine whether dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) could monitor progression of liver fibrosis in a piglet model, and which DCE-MRI parameter is most accurate for staging this disease. Sixteen piglets were prospectively used to model liver fibrosis and underwent liver DCE-MRI followed by biopsy on the 0, 5th, 9th, 16th, and 21st weekends after modeling of fibrosis. Time of peak (TOP), time to peak (TTP), positive enhancement integral (PEI), maximum slope of increase (MSI), and maximum slope of decrease (MSD) were measured and statistically analyzed for the monitoring and staging. As fibrosis progresses, TOP and TTP tended to increase, whereas MSI, MSD, and PEI tended to decrease (all P < 0.05). TOP, TTP, and MSI could discriminate fibrosis stage 0 from 1-4, 0-1 from 2-4, 0-2 from 3-4, and 0-3 from 4; PEI could distinguish the above-mentioned stages except 0-3 from 4; and MSD could distinguish stage 0-3 from 4, and 0 from 1-4 (all P < 0.05). For predicting stage ≥1, ≥2, and ≥3, the area under receiver operating characteristic curve (AUC) of MSI was largest among all parameters; for stage 4 AUC of TTP was largest. DCE-MRI has the potential to dynamically stage progression of liver fibrosis.

Utility of semiquantitative parameters to differentiate benign and malignant focal hepatic lesions

ObjectiveAny distinction and the usefulness of semiquantitative parameters derived from dynamic-contrast-enhanced (DCE) MRI obtained with extracellular gadolinium contrast agent in hemangiomas, hepatocellular carcinomas (HCC) and metastases of the liver was studied prospectively. MethodsSeventy-four focal liver lesions (consisted of 34 hemangiomas, 23 HCC, and 17 metastases) of the 37 patients underwent DCE–MRI (six phases). Functional coloured maps and subsequently semiquantitative parameters were obtained using the FuncTool. Maximum and average (avg) values of mean time to enhancement (MTE), positive enhancement integral (PEI), time to peak (TP), maximum slope of increase (MSI), maximum slope of decrease (MSD) values were measured by placing the region of interest. The diagnosis of HCC and metastases were proven histopathologically and/or clinically. ResultsThe mean values of the paremeters were: In hemangiomas, avgMTE: 271.2±4.7; avgPEI: 840.3±77.3; avgTP: 146.6±13.1; avgMSI: 999.1±108.4; avgMSD: 254.1±30.4. In HCC, avgMTE: 246±3.6; avgPEI: 424.9±31.6; avgTP: 132.8±9.5; avgMSI: 484.1±36.5; avgMSD: 109.1±13.3. In metastases, avgMTE: 248.1±8.2, avgPEI: 453.9±39.6; avgTP: 142.8±13.9; avgMSI: 472.6±50.4 and avg MSD: 200.1±38.2. Both maximum and avg values of MTE, PEI, MSI, and MSD were significantly higher in hemangiomas (P<.05). The most significant difference was found in avgPEI with 82.1% sensitivity and 67.6% specificity when 570 cutoff value was considered. The values however were not significantly different among HCC and metastases (P>.05). ConclusionsSemiquantitative DCE–MRI parameters provide useful, complementary, and quantitative information. This technique increases diagnostic value of extracellular gadolinium contrast agent to characterize focal liver lesions and may be useful for follow-up after local–regional therapies.

Capability of differentiating smokers with normal pulmonary function from COPD patients: a comparison of CT pulmonary volume analysis and MR perfusion imaging

To compare CT volume analysis with MR perfusion imaging in differentiating smokers with normal pulmonary function (controls) from COPD patients. Sixty-two COPD patients and 17 controls were included. The total lung volume (TLV), total emphysema volume (TEV) and emphysema index (EI) were quantified by CT. MR perfusion evaluated positive enhancement integral (PEI), maximum slope of increase (MSI), maximum slope of decrease (MSD), signal enhancement ratio (SER) and signal intensity ratio (RSI) of perfusion defects to normal lung. There were 19 class I, 17 class II, 14 class III and 12 class IV COPD patients. No differences were observed in TLV, TEV and EI between control and class I COPD. The control was different from class II, III and IV COPD in TEV and EI. The control was different from each class of COPD in RSI, MSI, PEI and MSD. Differences were found in RSI between class I and III, I and IV, and II and IV COPD. Amongst controls, MR detected perfusion defects more frequently than CT detected emphysema. Compared with CT, MR perfusion imaging shows higher potential to distinguish controls from mild COPD and appears more sensitive in identifying abnormalities amongst smokers with normal pulmonary function (controls). • Detailed information is needed to diagnose chronic obstructive pulmonary disease. • High-resolution CT provides detailed anatomical and quantitative information. • Magnetic resonance imaging is demonstrating increasing potential in pulmonary function imaging. • MR perfusion can distinguish mild COPD patients from controls. • MRI appears more sensitive than CT in identifying early abnormalities amongst controls.

Advanced Solid Tumors Treated with Cediranib: Comparison of Dynamic Contrast-enhanced MR Imaging and CT as Markers of Vascular Activity

To assess baseline reproducibility and compare performance of dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging versus DCE computed tomographic (CT) measures of early vascular response in the same patients treated with cediranib (30 or 45 mg daily). After institutional review board approval, written informed consent was obtained from 29 patients with advanced solid tumors who had lesions 3 cm or larger and in whom simultaneous imaging of an adjacent artery was possible. Two baseline DCE MR acquisitions and two baseline DCE CT acquisitions 7 days or fewer apart (within 14 days of starting treatment) and two posttreatment acquisitions with each modality at day 7 and 28 (±3 days) were obtained. Nonmodeled and modeled parameters were derived (measured arterial input function [AIF] for CT, population-based AIF for MR imaging; temporal sampling rate of 0.5 second for CT, 3-6 seconds for MR imaging). Baseline variability was assessed by using intra- and intersubject analysis of variance and Bland-Altman analysis; a paired t test assessed change from baseline to after treatment. The most reproducible parameters were DCE MR imaging enhancement fraction (baseline intrapatient coefficient of variation [CV]=8.6%), volume transfer constant (CV=13.9%), and integrated area under the contrast agent uptake curve at 60 seconds (CV=15.5%) and DCE CT positive enhancement integral (CV=16.0%). Blood plasma volume was highly variable and the only parameter with CV greater than 30%. Average reductions (percentage change) from baseline were consistently observed for all DCE MR imaging and DCE CT parameters at day 7 and 28 for both starting-dose groups (45 and 30 mg), except for DCE CT mean transit time. Percentage change from baseline for parameters reflecting blood flow and permeability were comparable, and reductions from baseline at day 7 were maintained at day 28. DCE MR imaging and DCE CT can depict vascular response to antiangiogenic agents with response evident at day 7. Improved reproducibility with MR imaging favors its use in trials with small patient numbers.

Value of 3T magnetic resonance dynamic contrast-enhanced and diffusion-weighted imaging in differential diagnosis of musculoskeletal tumors

To evaluate the value of magnetic resonance dynamic contrast-enhanced (MR-DCE) and magnetic resonance diffusion-weighted imaging (MR-DWI) in the differentiation of benign and malignant musculoskeletal tumors. Sixty-three patients with pathologically confirmed musculoskeletal tumors were examined with MR-DCE and MR-DWI. Using single shot spin echo planar imaging sequence and different b values of 400, 600, 800 and 1000 s/mm(2), we obtained the apparent diffusion coefficient (ADC) of the lesions. ADC values were measured before and after MR-DCE, with a b value of 600 s/mm(2). The 3D fast acquired multiple phase enhanced fast spoiled gradient recalled echo sequence was obtained for multi-slice of the entire lesion. The time-signal intensity curve (TIC), dynamic contrast-enhanced parameters, maximum slope of increase (MSI), positive enhancement integral, signal enhancement ratio, and time to peak (T(peak)) were also recorded. ADC showed no significant difference between benign and malignant tumors when the b value was 400, 600, 800, or 1000 s/mm(2), and it was not significantly different between benign and malignant tumors in both pre-MR-DCE and post-MR-DCE with b value of 600 s/mm(2). TIC were classified into four types type1 showed rapid progression and gradual drainage; type2 showed rapid progression but had no or slight progression; type 3 showed gradual progression; and type 4 had no or slight progression. Most lesions of type1 or type2 were malignant, whereas most lesions of type 3 or type 4 were benign. When using type1 and type 2 as the standards of malignancy, the diagnostic sensitivity and specificity was 87.23% and 50.00%, respectively. The types of TIC showed significant difference between benign and malignant musculoskeletal tumors(χ(2)=17.009,P=0.001). When using MSI 366.62 ± 174.84 as the standard of malignancy, the diagnostic sensitivity and specificity was 86.78% and 78.67%, respectively. When using T(peak)≤70s as the standard of malignancy, the diagnostic sensitivity and specificity was 82.89%and 85.78%, respectively. Positive enhancement integral and signal enhancement ratio showed no significant difference between benign and malignant musculoskeletal tumors. TIC, MSI and T(peak) of MR-DCE are valuable in differentiating benign from malignant musculoskeletal tumors. T(peak) has the highest diagnostic specificity, and TIC has the highest diagnostic sensitivity. The mean ADC value are no significant difference between benign and malignant tumors.

Post-operative monitoring of tissue transfers: Advantages using contrast enhanced ultrasound (CEUS) and contrast enhanced MRI (ceMRI) with dynamic perfusion analysis?

The immediate evaluation of microvascular tissue flaps with respect to microcirculation after transplantation is crucial for optimal monitoring and outcome. The purpose of our investigation was to evaluate the clinical value of contrast-enhanced ultrasound (CEUS) and contrast-enhanced MRI (ceMRI) for monitoring the integrity of tissue flaps in plastic surgery. To this end, we investigated 10 patients (47 ± 16 a) between postoperative day 7 and 14 who underwent flap surgery in order to cover tissue defects in various body regions. For CEUS we utilized the GE LOGIQ E9 equipped with a linear transducer (6-9 MHz). After application of 2.4 ml SonoVue, the tissue perfusion was detected in Low MI-Technique (MI < 0.2). The perfusion curves were quantitatively analyzed using digital video sequences (QONTRAST, Bracco, Italy) regarding peak % and relative blood flow (RBF). Furthermore, we investigated all tissue flaps using contrast-enhanced MRI (Magnetom Symphony TIM, Siemens) with a 3D-VIBE sequence and a time resolution of 7s. Thus, the transplants were completely captured in all cases. As perfusion parameters, the positive enhancement integral (PEI) as well as the maximum intensity projection time (MIP-time) were collected. For comparison of both applications, all parameters were displayed in color-coded resolution and analyzed by three independent readers. Depending on the flap thickness, 1-3 regions of interest (ROI) were investigated. Each ROI measured 1 × 3 cm. The subcutaneous ROI-1 showed a significantly lower rating regarding RBF in the ceMRI compared to CEUS (Mann-Whitney Rank-Sum test, p < 0.05). ROI-2 and -3 did not show any significant differences between the two applications. The frequency distribution showed good accordance in both modalities. Both imaging techniques detected 1 partial flap necrosis within the random area of cutaneous and subcutaneous layers, 1 hematoma as well as 1 insufficient perfusion over all tissue layers. After subsequent reoperation, graft loss could be prevented. At present, both technologies provide an optimal assessment of perfusion in cutaneous, subcutaneous and muscle tissue layers, whereby the detection of fatty tissue perfusion is currently more easily detected using CEUS compared to ceMRI.

Potential value of dynamic MR in predicting short-term effects of(chemo-)radiation therapy on cervical cancers

Objective To investigate the potential value of MR dynamic contrast enhanced imaging (DCE)in predicting short-term effects of(chemo-)radiation therapy on cervical cancers in vivo.Methods Thirty-two patients pathologically diagnosed as cervical cancers received MR-DCE scan before therapy.The following scans were taken at the 2nd to 3rd week after the radiation or(and)chemotherapy initiated,to calculate early size change.The fourth scan was performed within one month after the therapy to judge residues.DCE derived parameters include mean time to enhancement(MTE),positive enhancement integral (PEI),time to peak(TTP),maximum slope of increase(MSI)and maximum slope of decrease(MSD).Size and DCE parameters were compared and analyzed by Mann-Whitney test and Spearman teat Results There are 20 cases in non-residue group and 12 cases in residue group.In non-residue group,the maximal lengths in both horizontal and craniocaudal directions[(47.45±13.76)mm and(38.75±10.69)mm]were smaller than that in residue group [(61.08±13.73)mm and(53.67±16.05)mm],with statistical significance(Z=-2.455 and-2.650 respectively,P＜0.05).PEI in low-enhance areas of non-residue group(0.62±0.25)was significantly higher than that in residue group(0.39±0.14)(Z=-2.919,P＜0.05).At early time after radiation started,length changing rate and volume changing rate had medium to strong negative correlations with MSI in hish-enhance areas(r=-0.577 and-0.723 respectively,P＜0.05).Conclusions For cervical cancers,those with larger lengths and lower PEI in low-enhanced areas tend to have tumor residue when radiation therapy completed.Those low MSI in high-enhance areas tend to shrink quickly.It is suggested that volume and parameters of DCE before(chemo-)radiation therapy have the potential in predicting short-term therapeutic effect. Key words: Uterine cervical neoplasms; Magnetic resonance imaging; Treatment outcome

CT perfusion as index of activity of antiangiogenic treatment of metastatic carcinoma

3548 Background: the aim of this study was to evaluate the different Computed Tomography (CT) parameters, characterizing tissue perfusion by contrast medium in metastatis to define their relation with activity of an antiangiogenic compound, targeting the VEGF receptors 1 and 2, using this qualitative and quantitative method. Methods: 113 patients with metastatic renal cell, pancreatic, colonic carcinoma and melanoma treated with antiangiogenic compound, were studied by dynamic CT (64 slices, GE) : calculation of time to peak (TTP), positive enhancement integral (PEI), maximum slope of increase (MSI), maximum slope of decrease (MSD), blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface (PS) were performed. Value distributions in the normal and neoplastic wall, their variation after antiangiogenic therapies and their relation to mono and bidimensionnal or volume measurement and pathological vessel density (MVD) were evaluated. Results: BF, TTP, and especially PEI and PS were highter in tumor than in normal liver, respectively in 68, 76, 100 and 100%; PS was > 20 ml/min/100g in 100% of patients. PEI and PS decrease in 78% and 82% of patients submitted to antiangiogenic treatment at the first course. Decreased tumor perfusion (TP) was observed in patients responding to therapy, including liver metastasis. Furthermore, in 40 out of 60 patients with stable or progressive disease by RECIST, decreased TP was strongly correlated with clinical improvement. Significant correlation between PEI in tumor/PEI in the aorta and PS was found (R=0,679). Conclusion: CT perfusion could be reliable in the study of the neo-angiogenic process, characterized by an increase in vessel number, vascular permeability and flow into extra vascular spaces, better than direct measurement of the tumor or MVD count. Imaging will gain a role in monitoring targeted therapies, in the assessement of the evaluation of the antiangiogenic therapy and in the selection of patients eligible to be treated by this method. PEI in the tumor/PEI in the aorta and PS seem to be the most discriminative and predictive parameters. Others parameters (TTP, MSI, MSD) are operator and patient dependant. MTT is under evaluation as a good criterium of intersticial pressure around tumors No significant financial relationships to disclose.

An open, pharmacokinetic (PK) and mass balance study of 14C-AZD2171, incorporating DCE-CT evaluations

14140 Background: AZD2171 is an oral, highly potent and selective VEGF signaling inhibitor in clinical development. Methods: Patients with solid metastatic tumors received a single radiolabeled oral dose of 14C- AZD2171 45 mg; blood samples and all excretions were collected for evaluating the PK and metabolic profiles. After sufficient radioactivity recovery, patients started once-daily oral dosing with AZD2171 30 mg. The primary objective of the study was to determine the rates and routes of excretion of AZD2171 using 14C-AZD2171. Efficacy (RECIST), safety and tolerability were secondary objectives. The potential effects of AZD2171 on DCE-CT vascular parameters were also explored. Results: Six patients received treatment and remained on study for 64–171 days. In 5/6 patients, the amount of radioactivity recovered in the urine and feces samples within 168-hours post- dosing ranged from 84.8–93.0%; the analogous amount in the remaining patient was only 34.1%. In all patients, mean radioactivity recovered was 58.8% in feces and 20.8% in urine. Radioactivity appeared to be confined to plasma. Three patients (2 renal cell carcinoma; 1 mesothelioma) had a best RECIST response of stable disease (SD); 1 patient had a confirmed reduction in max tumor diameter of 10% to &lt;30%. Two patients had progressive disease and 1 patient was non-evaluable. The most common adverse events (AEs) were diarrhea (n=5) and hypertension (n=3); no grade 3 or 4 AEs occurred more than once. There was evidence of reductions in DCE-CT parameters post treatment, particularly perfusion, permeability surface product (PSP) and positive enhancement integral. For each of these parameters, a decrease from baseline outside the baseline reference range was recorded for 3 patients (including 2 with SD) at 1 month after the start of daily dosing of AZD2171. Overall, within-patient variability (W-PV) was generally low for all DCE-CT parameters measured and was consistently lower than between-patient variability. The W-PV was largest for PSP (18%) and lowest for mean transit time (7%). Conclusions: The primary route of AZD2171 elimination appears to be hepatic. AZD2171 was well tolerated and clinically meaningful disease stabilization was seen. Changes in tumor vascular parameters were detected by DCE-CT. [Table: see text]

Assessment of hemodynamics in precancerous lesion of hepatocellular carcinoma: Evaluation with MR perfusion

To investigate the hemodynamic changes in a precancerous lesion model of hepatocellular carcinoma (HCC). Hemodynamic changes in 18 Wistar rats were studied with non-invasive magnetic resonance (MR) perfusion. The changes induced by diethylnitrosamine (DEN) developed into liver nodular lesions due to hepatic cirrhosis during the progression of carcinogenesis. The MR perfusion data [positive enhancement integral (PEI)] were compared between the nodular lesions corresponding well with MR images and pathology and their surrounding hepatic parenchyma. A total of 46 nodules were located by MR imaging and autopsy, including 22 dysplastic nodules (DN), 9 regenerative nodules (RN), 10 early HCCs and 5 overt HCCs. Among the 22 DNs, 6 were low-grade DN (LGDN) and 16 were high-grade DN (HGDN). The average PEI of RN, DN, early and overt HCC was 205.67 +/- 31.17, 161.94 +/- 20.74, 226.09 +/- 34.83, 491.86 +/- 44.61 respectively, and their liver parenchyma nearby was 204.84 +/- 70.19. Comparison of the blood perfusion index between each RN and its surrounding hepatic parenchyma showed no statistically significant difference (P = 0.06). There were significant differences in DN (P = 0.02). During the late hepatic arterial phase, the perfusion curve in DN declined. DN had an iso-signal intensity at the early hepatic arterial phase and a low signal intensity at the portal venous phase. Of the 10 early HCCs, 4 demonstrated less blood perfusion and 6 displayed minimally increased blood flow compared to the surrounding parenchyma. Five HCCs showed significantly increased blood supply compared to the surrounding parenchyma (P = 0.02). Non-invasive MR perfusion can detect changes in blood supply of precancerous lesions.

Influence of post-treatment delay on the evaluation of the response to focused ultrasound surgery of breast cancer by dynamic contrast enhanced MRI

The assessment of the effectiveness of MRI-guided focused ultrasound surgery (MRIgFUS) of breast carcinomas can be performed by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters which monitor the presence of residual tumour. The aim of this study was to evaluate the effect of the post-treatment delay on this assessment. DCE-MRI data were acquired immediately and 3-14 days after MRIgFUS treatment of 26 tumours (<7 days, n = 6; = or > ge;7 days, n = 20). The percentage of residual tumour was determined histologically on the resected mass and correlated with two DCE-MRI parameters: increase in signal intensity (ISI) and positive enhancement integral (PEI). No correlation could be found between DCE-MRI data acquired immediately after treatment and the percentage of residual tumour. Good correlation coefficients were found for data acquired several days after treatment (ISI, r = 0.749; PEI, r = 0.778). However, they were higher when the post-treatment time interval was 7 days or more (ISI, r = 0.962; PEI, r = 0.934). These results suggest that a post-treatment delay of 7 days is necessary for the accurate assessment of the presence of residual tumour by DCE-MRI parameters.

Sequential hemodynamic changes in precancerous lesions of hepatocellular carcinoma: Experimental study with MR perfusion

Objective To determine the hemodynamic changes in precancerous lesions of HCC using MR perfusion(MRP). Methods During the period of carcinogenesis (12-20 weeks), 18 Wistar rats induced by DEN to develop into liver nodule lesions from hepatic cirrhosis were scanned by MR perfusion every week and compared lesion to lesion ,lesion to liver with pathology. Results Among 46 nodules showed by T_2WI of MRI and corresponded well with MR images and pathology, we identified 9 regenerative nodules (RN), 22 dysplastic nodules(DN), 10 early stage HCC (eHCC) and 5 HCC. The average positive enhancement integral(PEI)values of RN、DN、early HCC、HCC and hepatic parenchyma nearby of the nodules were 205.67±31.17,161.94±20.74,226.09±34.83,491.86±44.61,204.84±70.19 respectively. Comparing the blood perfusion between nodule and surrounding hepatic parenchyma, we found no difference with RNs. There were significant differences with dysplastic nodules (t=-3.64, P=0.02) which manifested decreased blood perfusion. Four of 10 early stage of HCCs demonstrated less blood perfusion and 6 displayed minor increased blood flow. Five HCC showed typical increased blood supply with significant difference (t=3.74, P=0.02). Conclusion Non-invasive MR perfusion imaging could demonstrate the changes of blood supply in precancerous lesions of hepatocellular carcinoma. Blood perfusion of HCC increased and DN decreased when compared with surrounding hepatic parenchyma.

MR imaging-guided focused ultrasound surgery of breast cancer: correlation of dynamic contrast-enhanced MRI with histopathologic findings.

To assess the value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters to monitor residual tumor following non-invasive MRI-guided focused ultrasound surgery (MRIgFUS) of breast tumors. DCE-MRI data were acquired before and after the MRIgFUS treatment of small breast tumors (d < 3.5 cm) for 17 patients. The lesion was surgically resected and the presence of residual tumor was determined by histopathological analysis. The percentage of residual tumor was correlated with three DCE-MRI parameters measured at the maximally enhancing site of each tumor: increase in signal intensity (ISI), maximum difference function (MDF) and positive enhancement integral (PEI). A good correlation was found between the ISI (r = 0.897), MDF (r = 0.789) and PEI (r = 0.859) parameters and the percentage of residual viable tumor determined by histopathology. A receiver operator characteristic curve analysis yielded a cutoff value for ISI at 20% with a sensitivity of 77% and a specificity of 100%. These results suggest that parameters from DCE-MRI data could provide a reliable non-invasive method for assessing residual tumor following MRIgFUS treatment of breast tumors.