Near-infrared fluorescence imaging of HER-2 protein over-expression in tumour cells

The aim of this study was to evaluate in vitro and in vivo imaging of HER-2-over-expressing tumours using near-infrared optical imaging. A fluorochrome probe was designed by coupling Cy5.5 to anti-HER-2 antibodies. Cells over-expressing (SK-BR-3 cells) or normally expressing (PE/CA-PJ34 cells) the HER-2 protein were incubated with the probe. After removing unbound probe molecules, fluorescence intensities were determined (a.u.: arbitrary units). Cells were additionally investigated using FACS and laser scanning microscopy. The probe was also injected intravenously into tumours bearing SK-BR-3 (n=3) or PE/CA-PJ34 (n=3). Whole-body fluorescence images were generated and analysed. The incubation of SK-BR-3 cells with the probe led to higher fluorescence intensities [2,133 (±143) a.u.] compared to controls [975 (±95) a.u.]. The results from FACS and immunocytochemical analysis were in agreement with these findings. A distinct dependency between the fluorescence intensity and the cell number used in the incubations was detected. In vivo, the relative fluorescence intensities in SK-BR-3 tumours were higher than in PE/CA-PJ34 tumours at 16–24 h after probe application. HER-2-over-expressing tumours were depictable in their original size. Labelling of HER-2 with Cy5.5 is suitable for in vitro and in vivo detection of HER-2-over-expressing tumour cells.     

Near-infrared fluorescence imaging of microcalcification in an animal model of breast cancer

RATIONALE AND OBJECTIVES: At present, there is no animal model of breast cancer that forms reproducible microcalcification. The aim of this study was to develop a straightforward, reproducible model system that could be used to develop multimodality contrast agents for the identification of breast cancer microcalcification. METHODS: The R3230 mammary adenocarcinoma cell line was implanted in the mammary fat pad of female Fischer 344 rats (two rats with two implanted tumors and two rats with a single implanted tumor). After growth to 1-2 cm in diameter, tumors were implanted with 100 microm hydroxyapatite crystals (positive control) or calcium oxalate crystals (negative control). Twenty-four hours after crystal implantation, rats were injected intravenously with a previously described near-infrared fluorescent bisphosphonate derivative known as Pam78, and the tumors were imaged using a reflectance optical imaging system. RESULTS: Tumors implanted with hydroxyapatite displayed bright, focal, near-infrared fluorescence in the area of crystal implantation. Control tumors, grown in the same animal and implanted with calcium oxalate, did not display any near-infrared fluorescence, even along the needle track used for crystal implantation. CONCLUSIONS: A simple and rapid animal model of focal calcification in breast cancer tumors has been developed and validated. The model used Pam78, a near-infrared fluorescent contrast agent specific for hydroxyapatite. The potential usefulness of the model for developing similar contrast agents for magnetic resonance and other imaging modalities is discussed.     

超顺磁氧化铁粒子增强MRI区分肿瘤转移性与良性淋巴结的实验研究

目的：研究超顺磁氧化铁粒子（SPIO）增强MRI鉴别肿瘤转移淋巴结与 正常和反应增生性淋巴结的价值。方法：新西兰兔18只，体重2．0－2．5kg。分析6只正常兔平扫及皮下间隙注射SPIO（10μmol Fe/肢）后1－48h的信号变化，用于研究SPIO增强效应－时间曲线；6只兔后腿肌内注射蛋黄乳胶，用于建立Guo窝淋巴结的反应性增生模型；6只兔后腿肌肉接种VX2肉瘤，并与病理检查对照.结果：平扫时正常、反应性增生的淋巴结和肿瘤转移淋巴结的信号强度无明显差异。SPIO增强后，正常和反应性增生淋巴结的信号强度降低，在12h时最明显，至48h时仍较明显，在T1WI、T2WI、质子密度加权像（PDWI）和T2WI分别为平扫时信号强度的51％、22％、41％和11％（P值均＝0．000）；肿瘤转移淋巴结的信号强度保持不变。结论：皮下间隙注射SPIO后MR成像可鉴别肿瘤转移淋巴结与正常和反应增生性淋巴结。     

Detection of zonal renal ischemia with contrast-enhanced MR imaging with a macromolecular blood pool contrast agent.

The potential of magnetic resonance (MR) imaging enhanced with albumin-(gadolinium diethylenetriaminepentaacetic acid [DTPA])35, a macromolecular blood pool marker, for detection of focal changes in renal perfusion was studied in a myoglobinuric acute renal failure (ARF) model in the rat. T1-weighted spin-echo postcontrast images of injured kidneys at 3 hours after glycerol injection showed three distinct zones: a strongly enhanced outer cortex, a low-intensity inner cortex, and a strongly enhanced medulla. The distinct band of low intensity in the inner cortex indicated zonal decreased blood volume, corresponding to published microsphere data showing zonal low perfusion in the inner cortex. Contrast differences between parenchymal zones were significant for at least 30 minutes. No focal ischemic changes could be delineated on nonenhanced images. Enhanced and nonenhanced images of injured kidneys obtained at 24 hours after glycerol injection revealed no zonal differentiation. Contrast-enhanced MR imaging data in this ARF model correlated well with pathologic data and microsphere perfusion results. Contrast-enhanced characterization of the ischemic phase of renal injury with MR imaging may improve specificity for the diagnosis of ARF and may serve as a marker for therapeutic intervention.     

Non-visualization of sentinel lymph nodes in penile carcinoma

Purpose The purpose of this study was to analyse the incidence and cause of non-visualization of sentinel lymph nodes on preoperative lymphoscintigrams for penile cancer and its implications for further management.Methods Preoperative lymphoscintigraphy was performed after injection of ^99mTc-labelled nanocolloid in 123 clinically node-negative penile carcinoma patients. Anterior dynamic lymphoscintigraphy was performed during 20 min immediately after tracer injection. Subsequently, 5-min anterior and lateral static images were obtained 30 min and 2 h post injection.Results Lymphatic drainage to both groins was seen in 98 patients (79%), unilateral drainage in 23 patients (19%) and no drainage at all in two patients (2%). Thus, in 27 (11%) of 246 groins, no sentinel node was visualized. The amount of administered tracer dose was associated with non-visualization (p=0.01). Unilateral drainage was initially interpreted as a normal physiological phenomenon. After the occurrence of a tumour-positive node in a non-visualized groin, we explore non-visualized groins by blue dye mapping and intraoperative palpation. Sentinel nodes were retrieved in four out of eight such groins, of which one contained metastasis.Conclusion In penile carcinoma patients, preoperative lymphoscintigraphy visualizes a sentinel node in 89% of groins. Visualization depends on the administered tracer dose. It is worthwhile to explore non-visualized groins. Sentinel nodes can be intraoperatively identified in more than half of these cases.     

头颈部肿瘤前哨淋巴结放射性核素探测研究进展

头颈部肿瘤前峭淋巴结是指肿瘤淋巴引流区域中的第一级淋巴结。探测头颈部肿瘤前哨淋巴结转移状况为肿瘤的准确分期和手术方案的制定提供了重要依据。放射性核素探讨可对前哨淋巴结进行显示和准确定位,检出率达90%以上,有着良好的应用前景。     

Phase I clinical evaluation of a new iron oxide MR contrast agent

The safety and magnetic resonance (MR) imaging potential of BMS 180549, a new superparamagnetic iron oxide contrast agent, were evaluated in a phase I, open-label, placebo-controlled study involving 41 healthy subjects. No clinically significant postdose changes in physical examination findings, vital signs, or electrocardiogram results were reported for any of the subjects evaluated. No clinically significant changes in clinical laboratory values were noted by the investigators. Fourteen adverse events considered not serious and considered possibly or definitely related to the drug were reported, three of which required minor treatment. Relaxation time measurements in plasma samples showed a strong, dose-dependent, and persistent decrease in T1 and T2 values. Significant changes in MR signal intensity of the blood pool and wellperfused organs (liver and spleen) were noted on both T1- and T2-weighted images. Changes in signal intensity of cervical lymph nodes were also observed at the higher doses and late postdose imaging times.     

Detection with echo-planar MR imaging of transit of susceptibility contrast medium in a rat model of regional brain ischemia.

Gradient-refocused echo-planar magnetic resonance (MR) images (TE = 18 msec) were acquired in rats during bolus injection of iron oxide particles, and the first pass of the contrast agent through the brain was monitored. In control rats, contrast agent (0.1 mmol/kg iron) produced significant signal-intensity (SI) reduction over the right hemisphere and similar declines over the left. SI loss occurred first in the cortex and basal ganglia and later in the periventricular regions, along the midline, and in the thalamic zone. Sequential volume-localized proton spectra acquired during transit of 0.02 mmol/kg iron showed substantial reduction in SI, slight asymmetric broadening, and no change in chemical shift of the water resonance. In rats with unilateral occlusion of the middle cerebral artery, peak reduction in ischemic brain SI was to 70% +/- 9% of control, while normal brain SI was reduced to 18% +/- 2% (P less than .01), allowing distinction of the ischemic regions. The presence and location of injury were confirmed with diffusion-weighted imaging and postmortem vital staining. These results demonstrate abnormal transit profiles in a rat model of regional brain ischemia. Evaluation of dynamic contrast delivery patterns may provide unique information in early brain ischemia.     

基于聚合物微泡的超声/荧光双模态造影剂的制备及成像研究

目的 基于模块化思想,通过将具有荧光成像特性的量子点复合到具有超声响应特性的高分子微泡中,制备超声/荧光双模态医学造影剂.方法 将500 mg聚乳酸、50 mg樟脑、0.5ml油酸修饰的硒化镉/硫化锌量子点(CdSe/ZnS,2.3 μmol/L)溶解分散于10 ml二氯甲烷形成有机相,用碳酸铵溶液构成内水相,用聚乙烯醇溶液构成外水相,采用双乳溶剂挥发法和冷冻干燥技术相结合的方法制备兼具超声/荧光双模态成像功能的荧光微泡.用扫描电子显微镜观察荧光微泡形貌,以荧光分光光度计对其发光性能进行表征.搭建体外超声/荧光成像装置,以推注生理盐水的声像图为对照,观察装置中硅胶管注入荧光微泡后的超声对比增强情况和荧光增强情况及两者同步成像效果.评价荧光微泡在体内超声/荧光双模式下对新西兰大白兔肾脏的成像效果.结果 荧光微泡呈规则的球形,具有中空结构,平均粒径为(1.62±1.47) μm,超过99％的微泡直径小于8μm,能够满足超声造影剂大小的基本要求;荧光微泡的荧光发射峰位于632 nm,并能维持量子点良好的发光特性.体外超声/荧光成像结果示:管腔充满生理盐水时,声像图呈完全无回声;推注荧光微泡后,有造影剂的部分回声增强;紫外灯照射下,有造影剂的液柱见明亮红色荧光.推注荧光微泡后,兔肾脏在声像图上清晰显影.结论 成功制备基于聚合物微泡的超声/荧光双模态造影剂,该造影剂具有良好的回声特性和荧光成像能力,可以弥补单一造影剂的缺陷与不足.     

Cell tracking with gadophrin-2: a bifunctional contrast agent for MR imaging,optical imaging,and fluorescence microscopy

The purpose of this study was to assess the feasibility of use of gadophrin-2 to trace intravenously injected human hematopoietic cells in athymic mice, employing magnetic resonance (MR) imaging, optical imaging (OI), and fluorescence microscopy. Mononuclear peripheral blood cells from GCSF-primed patients were labeled with gadophrin-2 (Schering AG, Berlin, Germany), a paramagnetic and fluorescent metalloporphyrin, using established transfection techniques with cationic liposomes. The labeled cells were evaluated in vitro with electron microscopy and inductively coupled plasma atomic emission spectrometry. Then, 1×10⁶–3×10⁸ labeled cells were injected into 14 nude Balb/c mice and the in vivo cell distribution was evaluated with MR imaging and OI before and 4, 24, and 48 h after intravenous injection (p.i.). Five additional mice served as controls: three mice were untreated controls and two mice were investigated after injection of unlabeled cells. The contrast agent effect was determined quantitatively for MR imaging by calculating signal-to-noise-ratio (SNR) data. After completion of in vivo imaging studies, fluorescence microscopy of excised organs was performed. Intracellular cytoplasmatic uptake of gadophrin-2 was confirmed by electron microscopy. Spectrometry determined an uptake of 31.56 nmol Gd per 10⁶ cells. After intravenous injection, the distribution of gadophrin-2 labeled cells in nude mice could be visualized by MR, OI, and fluorescence microscopy. At 4 h p.i., the transplanted cells mainly distributed to lung, liver, and spleen, and 24 h p.i. they also distributed to the bone marrow. Fluorescence microscopy confirmed the distribution of gadophrin-2 labeled cells to these target organs. Gadophrin-2 is suited as a bifunctional contrast agent for MR imaging, OI, and fluorescence microscopy and may be used to combine the advantages of each individual imaging modality for in vivo tracking of intravenously injected hematopoietic cells.     

Optical imaging of experimental arthritis using allogeneic leukocytes labeled with a near-infrared fluorescent probe

Purpose The purpose of this study was to assess the feasibility of inflammation detection in an antigen-induced arthritis model using fluorescent leukocytes and optical imaging. Methods Antigen-mediated monoarthritis was induced in the right knee of 12 Sprague-Dawley rats. Six rats remained untreated and six rats were treated with cortisone. All rats received ex vivo fluorescent-labeled rat leukocytes. Optical images of both knees were acquired before and at 5 min, 1 h, 4 h, and 24 h after cell injection. Images were evaluated qualitatively and quantitatively by calculating signal intensity ratios between the right arthritic (A) and contralateral normal (N) knee. A/N ratios were tested for significant differences between baseline values and values after cell injection using a paired t test as well as between the untreated and cortisone-treated group using an unpaired t test. Synovial specimens were processed and evaluated for labeled cells with fluorescence microscopy. Results At 4 h and 24 h p.i., the A/N ratios of untreated arthritic knees showed a significant signal increase compared with baseline values (p<0.05) and a significant difference compared with A/N ratios of cortisone-treated animals (p<0.05). Fluorescent microscopy confirmed the presence of labeled cells in the arthritic synovium. Conclusion Inflammation in antigen-induced arthritis can be detected with ex vivo labeled allogenic leukocytes and optical imaging.     

Measurement of renal transit of gadopentetate dimeglumine with echo-planar MR imaging

Times of peak gadolinium concentration ([Gd]) after intravenous (IV) and left ventricular (LV) bolus injection of gadopentetate dimeglumine were determined in renal cortex and medulla in normal rabbits and in rabbits after saline load (overhydration) or hemorrhage (dehydration). Magnetic resonance images were obtained with echo-planar inversion-recovery sequences, and signal intensity-versus-time curves in cortical and medullary regions of interest were converted to [Gd]-versus-time curves. Cortical perfusion measured with microspheres demonstrated that the three physiologic states were significantly different. There were three separate [Gd] peaks in both the cortex and medulla as the bolus moved from one anatomic compartment to the next. The first cortical peak occurred sooner after LV than after IV bolus injection (P <.05) and later in dehydrated than in normal and overhydrated rabbits (P <.05). The first medullary peak always followed the first cortical peak by about 6–10 seconds and mirrored the cortical patterns. The second and third cortical peaks were consistent with proximal and distal tubular transit. These peaks similarly showed faster response to LV than IV injection and were delayed by hemorrhage. The authors conclude that quantitative physiologic information can be obtained with dynamic contrast-enhanced MR imaging of the kidney.     

Characterization of a gadolinium-labeled cholesterol derivative as an organ-specific contrast agent for adrenal MR imaging

The purpose of the study was to determine if derivatization of cholesterol with a paramagnetic label could result in an organ-specific contrast agent for magnetic resonance imaging of the adrenal glands. Gadolinium-DO3A-labeled cholesterol was synthesized and the relaxivities in water and blood plasma determined at 0.47 T and 40°C. Organ distribution was measured at 2 (n = 2) and 24 (n = 2) hours after intravenous injection of a 50 μmol/kg dose of Gd-DO3A-cholesterol in rats weighing 220–240 g. T1-weighted spin-echo images were acquired at 2 T before and after injection of 50 μmol/kg Gd-DO3A-cholesterol (n = 2) and Gd-DTPA (diethylenetriaminepentaacetic acid)-albumin (n = 2). More than 99% of the Gd-DO3A-cholesterol was found to be protein bound in bovine serum. High T1 and T2 relaxivities were found in water and plasma. High tissue concentrations of Gd-DO3A-cholesterol were found only in adrenal glands and liver. At 24 hours, adrenal gadolinium concentrations were about 10 times higher than in blood. At 2 hours after injection of Gd-DO3A-cholesterol. enhancement was 162% in adrenal glands and 146% in liver. With Gd-DTPA-albumin, enhancement values were 57% and 56%. respectively.     

MR扩散加权成像中应用ADC值鉴别良、恶性淋巴结的Meta分析

目的 采用循证医学Meta分析的方法,探讨DWI-ADC值鉴别良、恶性淋巴结的可行性.方法 检索1998年至今公开发表的良、恶性淋巴结DWI-ADC值差别研究的中、英文文献,对符合纳入条件的原始研究进行质量评价,提取特征信息.对提取的信息进行异质性检验.根据异质性检验结果选择相应的效应量合并模型.合并效应量为ADC值差别的加权平均差和诊断性试验的敏感性、特异性、阳性似然比、阴性似然比、诊断比值比,计算验前、验后概率,以定性和定量的方法研究良、恶性淋巴结DWI-ADC值差别及临床应用价值.结果 符合纳入标准的文献共15篇,研究对象735例,淋巴结1963个.Meta回归分析、亚组分析和敏感性分析显示,2项良性淋巴结来自健康对照和1项采用化学位移选择法压脂技术的研究,对汇总结果影响较大,合并效应量时予以剔除.恶性淋巴结与良性淋巴结的ADC值的加权均数差值为-0.355×10-3mm2/s[95％可信区间(CI) -0.423×10-3～-0.288×10-3mm2/s].虽然各研究鉴别良、恶性淋巴结采用的ADC界值不同,但鉴别良、恶性淋巴结的诊断指标稳定,汇总敏感性、特异性、阳性似然比、阴性似然比、诊断比值比和汇总受试者工作特征曲线下面积分别为:0.87(95％ CI:0.79～0.92)、0.87 (95％ CI:0.82～0.90)、6.5 (95％ CI:4.7～9.2)、0.15(95％ CI:0.09～0.25)、43 (95％ CI:21～87)、0.93 (95％ CI:0.90～0.95),ADC提示良性的淋巴结验后恶性率为6％,ADC提示恶性的淋巴结验后恶性率为72％.结论 恶性淋巴结ADC值低于良性淋巴结,是一种准确性较高的鉴别良、恶性淋巴结的无创性检查方法.     

Pelvic lymph node visualization with MR imaging using local administration of ultra-small superparamagnetic iron oxide contrast

PURPOSE: To determine if interstitial injection of iron oxide particles improves visualization of pelvic lymph nodes at magnetic resonance imaging (MRI) and to determine the effect of injection site on location of visualized nodes. MATERIALS AND METHODS: In nine healthy volunteers, ferumoxtran-10 iron oxide (0.28 mg iron per kg) was injected into the anterior thigh (three subjects) or perianal (three subjects) or periprostatic tissues (three subjects). MRI at 1.5 T was performed before injection and one, three, and seven days after injection. RESULTS: The mean of 30 nodes seen post-injection was greater than the mean of 5.8 seen pre-injection (P < 0.001). After thigh injection, a mean of three internal vs. 36 external nodes were seen. Compared with thigh injection, there was a higher fraction of internal nodes with perianal (mean of nine internal vs. 14 external, P < 0.001) and periprostatic injection (mean of 11 internal vs. five external, P < 0.001). More nodes were seen with gradient-echo sequences than with other sequences (P < 0.001). CONCLUSION: Interstitial injection of iron oxide particles increases visualization of pelvic lymph nodes. Perianal and periprostatic injection increases the number of internal pelvic lymph nodes seen compared with thigh injection.     

钆喷替酸葡甲胺-白蛋白增强MR淋巴造影鉴别良恶性淋巴结的实验研究

目的 步探索组织间隙应用钆喷替酸葡甲胺-白蛋白（HSA-Gd-DTPA）的阳性MR淋巴造影在鉴别良、恶性淋巴结中的价值。方法 西兰兔12只，体重2．0～2．5kg。6只兔单侧后腿肌肉注射蛋黄乳胶，用于建立腘淋巴结的反应性增生模型（反应性增生组），另6只兔单侧后腿肌肉接种VX2肉瘤，用于建立胭窝淋巴结肿瘤转移模型（VX2肉瘤转移组），对侧正常胭窝淋巴结用作对照（正常组）。分析各组胭窝淋巴结在平扫及组织间隙注射0．04～0．05mmol／kgHSA-Gd-DTPA24h后的MR[特征并与病理检查对照。结果平扫时，正常组（共计6个淋巴结）、反应性增生组（共计8个淋巴结）和VX2瘤转移组（共计10个淋巴结）均表现为T1WI上等或稍高信号，T2WI上高信号。增强后24h，正常组和反应性增生组淋巴结呈明显的均匀强化，而8个转移性淋巴结分别表现为环状、云絮状和“充盈缺损”等不均匀的强化模式，2个淋巴结为完全不强化。结论 织间隙应用HSA-Gd-DTPA的阳性MR淋巴造影可准确鉴别良、恶性淋巴结。     

Use of a decision-analytic model to support the use of a new oral US contrast agent in patients with abdominal pain

RATIONALE AND OBJECTIVES: The authors performed this study to compare the cost and diagnostic abilities of ultrasound (US) performed with and without the use of an oral contrast material recently approved by the U.S. Food and Drug Administration. MATERIALS AND METHODS: An interactive decision-analytic model was constructed to compare US performed with and without contrast material (SonoRx; Bracco Diagnostics) for the evaluation of patients with abdominal pain who were suspected of having pancreatic disease. The model considered all resources that might be used to evaluate a patient suspected of having pancreatic disease (eg, US, computed tomography [CT], endoscopic retrograde cholangiopancreatography, fine-needle aspiration biopsy, and open biopsy). The literature and an expert panel were the clinical data sources. Cost estimates were based on Medicare and non-Medicare reimbursements. The primary cost-effectiveness measure was the cost to achieve a diagnosis. RESULTS: SonoRx-enhanced US was less expensive than unenhanced US ($714 vs $808, respectively, with Medicare costs; $1,612 vs $1,878, respectively, with non-Medicare costs) and as effective (0.785 vs 0.782, respectively). SonoRx-enhanced US was more cost-effective than unenhanced US ($909 vs $1,034, respectively, with Medicare costs; $2,052 vs $2,401, respectively, with non-Medicare costs). This relationship was maintained throughout extensive sensitivity analyses. CONCLUSION: SonoRx-enhanced US is more cost-effective than unenhanced US, primarily because it avoids the need for CT. CT may be avoided owing to the higher probability of obtaining optimal US scans with oral contrast material.     

Diffuse optical tomography of the breast: preliminary findings of a new prototype and comparison with magnetic resonance imaging

This paper presents an evaluation of a prototype diffuse optical tomography (DOT) system. Seventeen women with 18 breast lesions (10 invasive carcinomas, 2 fibroadenomas, and 6 benign cysts; diameters 13–54 mm) were evaluated with DOT and magnetic resonance imaging (MRI). A substantial fraction of the original 36 recruited patients could not be examined using this prototype due to technical problems. A region of interest (ROI) was drawn at the lesion position as derived from MRI and at the mirror image site in the contralateral healthy breast. ROIs were assessed quantitatively and qualitatively by two observers independently in two separate readings. Intra- and interobserver agreements were calculated using kappa statistics (k) and intraclass correlation coefficients (ICCs). Discriminatory values for presence of malignancy were determined by receiver operating characteristic (ROC) analyses. Intraobserver agreements were excellent (k 0.88 and 0.88; ICC 0.978 and 0.987), interobserver agreements were good to excellent (k 0.77–0.95; ICC 0.96–0.98). Discriminatory values for presence of malignancy were 0.92–0.93 and 0.97–0.99 for quantitative and qualitative ROC analysis, respectively. This DOT system has the potential to discriminate malignant from benign breast tissue in a reproducible qualitative and quantitative manner. Important technical improvements are required before this technique is ready for clinical application.     

对比剂铁羧葡胺在正常兔MR脑灌注的初步实验研究

目的 探讨铁羧葡胺(Resovist)应用于脑MR灌注加权成像(PWI)的可行性、给药方法以及最佳剂量.方法 健康新西兰大白兔30只,随机数字法平均分为A、B、C、D、E组.其中A、B、C、D 4组分别给予4、8、16、32 μmol Fe/kg;E组设为对照,给予0.2 mmol/kg的钆喷替酸葡甲胺(Gd-DTPA).所有动物均行MR PWI,获得相应信号强度一时间曲线图,并分别计算脑灰质、白质的最大信号下降百分比(SRRmax)、局部脑血容量(rCBV)和灰质与白质rCBV之比(QRCBV)、SRRmax之比(QRR max).所得数据,根据资料性质,行配对t检验和单因素方差分析.结果 Resovist能快速团注,4组均获得满意的信号强度一时间曲线图;4种剂量的Resovist对实验兔脑灰质和白质均有良好的分辨率.A、B、C、D、E 5组脑灰质和白质的rCBV分别为(50.48±3.84)、(25.57±2.10),(94.69±2.60)、(45.33±3.14),(141.13±6.26)、(67.67±4.65),(243.75±5.90)、(162.06±5.14),(84.60±3.60)、(41.36±2.18)ml/100 g;灰质和白质的SRRmax分别为:(13.70±1.50)%、(7.38±0.41)%,(31.01±4.06)%、(16.49±2.35)%,(43.81±3.42)%、(21.64±4.14)%,(64.49±5.35)%、(43.61±5.78)%,(27.78±2.98)%、(14.42±2.25)%;各组脑灰质与白质检测数据比较差异均有统计学意义(P值均<0.01).A、B、C、D、E 5组QrCBV分别为1.98±0.07、2.09±0.11、2.09±0.07、1.50±0.01、2.05±0.03;QSRRmax分别为:1.85±0.11、1.88±0.06、2.06±0.25、1.49±0.09、1.94±0.12;5组间差异均有统计学意义(QrCBV的F值为85.076,QSRR max的F值为13.915,P均<0.01).A、B、C 3组QrCBV值和QSRR max值差异无统计学意义(P>0.05);而D组QrCBV值和QSRR max值显著低于A组(P<0.01).结论 Resovist应用于MR脑灌注是可行的,适宜剂量4～16 μmol Fe/kg.     

Delineation of liver necrosis using double contrast-enhanced MRI

The purpose of this study was to demonstrate the potential usefulness of the combination of gadolinium and dysprosium to enhance the difference between normal and necrotic liver tissue. Small regions of acute necrosis were induced by injecting 200–300 μl of 95% alcohol into the liver of 26 rats. MRI was performed 24 hours after necrosis induction, before and immediately after injection of one or both contrast agents. Using a mixed T1/T2-weighted sequence, the signal intensity (SI) of the normal liver was reduced by 70%, whereas the necrotic regions had more than a 50% increase in SI after double contrast. The region that was enhanced corresponded largely with the region of necrosis as observed postmortem. The lesion size, when identified, was largely underestimated using either of the agents alone, albeit using the common pulse sequences. The double contrast effect of simultaneous administration of gadolinium and dysprosium allows accurate delineation of liver necrosis.