前列腺癌的MR扩散成像初步研究

目的初步评价MR扩散成像(DWI)对前列腺癌的诊断可行性。方法28例前列腺癌患者及20例前列腺正常的对照组受试者行MR DWI检查,使用回波平面扩散张量成像序列,b值为1000s/mm2。测量正常前列腺外周带及前列腺癌区域的表观扩散系数(ADC)值。同时测量每位受检者膀胱区域的ADC值。结果48例中44例(91.7%)获得前列腺外周带和膀胱的ADC值。24例前列腺癌灶的ADC值为(0.35±0.06)×10-3mm2/s,20例正常前列腺外周带的ADC值为(1·35±0.30)×10-3mm2/s,前列腺癌灶较正常前列腺外周带ADC值低(t=11.99,P=0.00)。前列腺癌患者膀胱的ADC值为(1.27±0.21)×10-3mm2/s,对照组膀胱ADC值为(1.29±0.30)×10-3mm2/s,2组之间差异无统计学意义(t=1.15,P=0.48)。结论MR DWI可用于前列腺的检查。前列腺癌灶与正常前列腺外周带ADC值的差别有可能用于前列腺癌的鉴别诊断。     

MR扩散加权成像在评价前列腺癌内分泌治疗中的应用价值

目的探讨内分泌治疗前后前列腺外周带癌区和非癌区的表观扩散系数（ADC）值的变化情况。方法对经手术病理或穿刺活检证实的14例前列腺癌和18例内分泌治疗6个月以上的前列腺癌患者行MR扩散加权成像（DWI）。依病理结果，将前列腺6分区归类为癌区和非癌区，测量每个分区的ADC值，同时测量每例膀胱、闭孔内肌的ADC值，对2组的结果进行比较。结果未治疗组14例癌区和非癌区的ADC值分别为（1．22±0．25）×10^-3、（1．59±0．19）×10^-3mm^2／s，差异有统计学意义（t=7．03，P〈0．01）。经内分泌治疗后的18例癌区的ADC值升高至（1．46±0．30）×10^-3mm^2／s，非癌区的ADC值为（1．59±0．24）×10^-3mm^2／s，癌区和非癌区之间ADC值差异有统计学意义（t=2．46，P〈0．05）。两组癌区之间ADC值差异有统计学意义（t=4．66，P〈0．01），非癌区、膀胱、闭孔内肌的ADC值差异无统计学意义（t值分别为0．06、0．48、1．64，P值均〉0．05）。结论ADC值用于判断前列腺癌内分泌治疗效果有应用前景。     

MR扩散张量成像在前列腺癌诊断中的价值

目的 探讨MR DTI在前列腺癌诊断中的价值.方法 回顾性分析2009年10月至2010年12月期间,临床怀疑为前列腺癌且行MR常规检查及DTI扫描的44例患者的资料.病理证实为前列腺癌16例、良性前列腺增生28例.采用t检验比较前列腺癌、良性前列腺增生患者间各向异性分数(FA)值及ADC值的差异,采用ROC曲线分析FA值及ADC值对前列腺癌诊断效能,并初步确定前列腺癌FA值及ADC值诊断阈值.结果 前列腺癌区和良性前列腺增生的FA值分别为0.308±0.084和0.203±0.029,ADC值分别为(0.883±0.192)×10-3和( 1.408±0.130)×10-3mm2/s,差异均有统计学意义(￡值分别为4.833和10.779,P值均＜0.01).ROC曲线上,ADC曲线下面积为0.996(95％可信区间为0.984～1.007),FA值曲线下面积为0.904(95％可信区间为0.812～0.996),FA值联合ADC值的曲线下面积为0.996(95％可信区间为0.984～1.007).ADC值阈值为0.725×10-3mm2/s,敏感度为100.0％,特异度为96.0％;FA值阈值为0.311,敏感度为100.0％,特异度为68.7％.结论 DTI成像能为前列腺癌诊断及鉴别诊断提供有价值的信息,有助于提高对前列腺癌的诊断能力.     

MR动态增强、扩散成像和波谱分析在前列腺癌诊断中的价值

目的探讨MR动态增强扫描(DCE-MRI)、扩散加权成像(DWI)和三维氢质子MR波谱分析(3D1H-MRS)在前列腺癌诊断中的价值。方法经穿刺活检、手术病理或随访证实的32例前列腺癌及64例前列腺增生患者,以及29例健康志愿者经MR常规扫描、DCE-MRI、DWI和MRS扫描,分别测量前列腺癌、前列腺增生病灶和正常前列腺中央腺区和正常周围带强化后的相对信号强度值、DWI信号强度值和表观扩散系数(ADC)值,以及胆碱／枸橼酸盐(Cho／Cit)和[Cho+肌酸(Cr)]／Cit比值,并经方差分析比较不同组织和病灶间差异。结果经DCE-MRI检查,22例前列腺癌患者中18例病灶区呈早期明显强化,并快速下降;40例前列腺增生患者中38例呈早期明显强化并逐渐上升至中晚期达峰值后缓慢下降,除0及120 s两时间段前列腺癌与前列腺增生组织两者之间差异无统计学意义(P>0．05)外,正常周围带、增生与癌三者的相对信号强度在其余每个时段均差异有统计学意义(P<0．05)。经DWI检查前列腺癌患者26例于ADC图上病灶呈明显低信号,ADC值为(104．23±26．15)×10-5mm2／s,43例前列腺增生患者病灶区平均ADC值为(175．21±64．86)×10-5mm2／s,除正常前列腺周围带与前列腺增生之间ADC值差异无统计学意义(P>0．05)外,前列腺癌、前列腺增生和正常前列腺中央腺区之间差异均有统计学意义(P<0．05)。MRS检查前列腺癌17例,其病灶区Cho／Cit比值为2．26±0．91,(Cho+Cr)／Cit比值为2．85±1．01,35例前列腺增生患者病灶区平均Cho／Cit比值为0．46±0．23,(Cho+Cr)／Cit比值为0．57±0．20。除正常前列腺周围带与正常前列腺中央腺区之间差异无统计学意义(P>0．05)外,前列腺癌、前列腺增生和正常前列腺组织其余各组间差异均有统计学意义(P<0．05)。DCE-MRI、DWI和MRS 3种检查方法在前列腺癌诊断敏感度、特异度和准确度均达70％以上,而通过3种检查方法的联合应用,其敏感度、特异度和准确度分别达87．50％、94．74％、92．59％。结论DCE-MRI、DWI和MRS 3种检查方法在前列腺癌诊断中具有特征性表现,而3种检查方法的联合应用又将极大地提高MRI诊断前列腺癌的正确诊断率。     

前列腺癌的MR诊断及影响因素

目的 :研究 MR对前列腺癌的定性诊断及分期诊断的能力 ,讨论对诊断准确性有影响的因素。方法 :回顾性分析 2 45例、30 8人次行前列腺 MR检查的影像资料及临床资料 ,着重研究了其中 15 8例病理证实的前列腺癌患者的 MR表现及分期 ,并与临床病理分期对照。结果 :MR能显示 80 .4%的前列腺癌 ,分期的准确率为 81.1%。前列腺活检后 3周内、内分泌治疗后、既往患前列腺炎的患者定性诊断准确率稍低 ,注意观察前列腺尖部、神经血管束及包膜轻度不规则的情况可提高定性和分期诊断的准确性。对中央带病灶 MR诊断效果不好。结论 :MR是评价前列腺癌的一种很好的影像学方法。对病史资料的全面了解、根据情况运用多种 MR检查方法及不断总结提高诊断者的经验会提高 MR对前列腺癌的定性诊断和分期诊断的准确率。     

MR直肠内线圈波谱成像在前列腺癌鉴别诊断中的作用

目的:探讨磁共振波谱成像在正常前列腺、前列腺癌、前列腺增生及外周带良性结节中的诊断价值.方法:对经病理证实的前列腺癌35例、前列腺增生34例(包括7例外周带良性结节)进行MRS定量分析.选前列腺中间层或病灶最大层面作为感兴趣区,测量其(Choline Creatine)/Citrate即CC/C的比值.结果:正常前列腺外周带、前列腺癌区、外周带良性结节和前列腺增生中央带的CC/C平均比值分别为0.94±0.53、2.23±1.67、1.19±0.64和0.93±0.49.前列腺癌与前列腺外周带良性结节及前列腺增生之间的差异均有统计学意义(t值分别为2.78和4.4,P值分别为0.01和0.001).前列腺癌的CC/C值最高,CC/C＞1.5者18例(51.4%);其余各组CC/C≈1.结论:前列腺癌的CC/C值显著升高,MRS有助于前列腺癌的鉴别诊断.     

扩散加权成像鉴别前列腺癌及良性前列腺增生的价值

目的探讨良性前列腺增生(BPH)和前列腺癌(PCa)的扩散加权成像(DWI)和表观扩散系数(ADC)图表现,及对PCa的鉴别诊断价值。方法分析18例BPH和25例PCa的DWI和ADC图表现,并分别测量癌肿区的ADC值及BPH的外周带(PZ)及中央腺体(CG)的ADC值,比较其间是否存在差异。结果BPH的DWI和ADC图上PZ信号近似均一,CG信号欠均匀。PCa在DWI上呈高信号,ADC图呈低信号,均能直观显示癌灶范围。受侵犯的精囊和骨盆骨转移灶DWI上呈高信号,ADC图呈低信号。PCa的ADC值[(0．49±0．09)×10-3mm2／s]与BPH的PZ及CG的ADC值[(1．27±0．14)×10-3mm2／s、(0．96±0．14)×10-3mm2／s]比较,差异均有统计学意义(t值分别为-52．46、-31．49,P值均<0．01),PCa的ADC值与BPH的PZ无重叠,与CG也仅有少量重叠(1／127,0．7％)。结论DWI和ADC图可显示PCa位置、范围及周围侵犯、转移情况;根据DWI和ADC图上病变的信号特点及ADC值可以鉴别BPH和PCa。     

MR灌注成像在前列腺疾病诊断中作用的初步探讨

目的探讨MR灌注成像在前列腺良恶性病变中的初步应用,评价血管内皮生长因子(VEGF)和微血管密度(MVD)与MR灌注成像各指标的关系。方法对临床诊断为前列腺疾病的70例患者,其中良性前列腺增生(BPH)42例,前列腺癌(PCa)28例,进行MR灌注成像,并对标本进行免疫组织化学检测;分析病变的灌注曲线最大线性斜率(SSmax)、T2*弛豫率(△R2* peak)与免疫组织化学检查结果(VEGF、MVD)的相关性。结果(1)BPH组增生结节灌注曲线的SSmax及△R2*peak分别为:33．5±3．1、1．5±0．1;PCa组癌灶灌注曲线的SSmax及△R2*peak分别为:58．4±4．7、3．1±0．5,两者之间差异有统计学意义(t值分别为2．13、2．29,P值均<0．05);PCa组高、中、低分化腺癌的SSmax分别为:52．3±3．4、56．4±4．3、60．7±5．2,差异有统计学意义(F=132．04,P< 0．05),△R2*peak分别为:2．9±0．4、3．1±0．5、3．2±0．7,差异有统计学意义(F=114．82,P<0．05)。(2)BPH组VEGF阳性9例,MVD值为22．76±6．54;PCa组VEGF阳性为24例,MVD值为71．38±9．17;PCa的VEGF和MVD的表达水平明显高于BPH患者(X2=27．86,P<0．01;t=20．4,P< 0．01),PCa、BPH的VEGF表达与MVD表达呈正相关性(P<0．01);灌注加权成像(PWI)参数SSmax、△R2*peak与VEGF、MVD具有相关性(P<0．01)。结论PWI的有关指标(SSmax、△R2*peak)与MVD和VEGF的表达水平相关,有可能为前列腺疾病良恶性的鉴别提供信息。     

前列腺癌活检后的MR表现及对诊断准确性的影响

目的 :评价前列腺癌穿刺活检后的MR表现及其对MR诊断准确性的影响。方法 :将 10 2例活检证实的前列腺癌患者分为两组 ,A组为活检后 3周内行MR检查者 ,B组为活检后 3周到 1年内行MR检查者。对两组患者的MR表现进行分析 ,并和穿刺病理结果对照 ,研究了MR诊断的准确性。结果 :A组中有 5 1.4% (18/ 35 )出现活检后血肿 ,B组中有 14 .9% (10 / 6 7)出现血肿及其后遗改变 (P 0 .0 1)。和穿刺活检的病理结果对照 ,A组患者MR诊断准确率为 91.4% ,假阳性率为 2 0 .5 % ;B组患者MR诊断准确率为 94.2 % ,假阳性率为 11.4%。两组之间诊断准确率没有显著差异 ,但假阳性率有显著性差异 (P 0 .0 5 )。结论 :前列腺活检后 3周内易出现血肿 ,使MR诊断的假阳性率增高。对前列腺癌的MRI检查应于活检 3周以后或活检之前进行。     

比较MR扩散加权成像和经直肠超声引导穿刺Gleason评分评估前列腺癌侵袭性的差异

目的 比较DWI ADC值和经直肠超声引导穿刺所得Gleason评分评估前列腺癌侵袭性的作用.方法 回顾性分析51例经穿刺活检确诊为前列腺癌,于1.5 TMR扫描仪上行前列腺DWI检查,并进行了前列腺癌根治术的患者资料.以前列腺癌根治术标本为参考,测量前列腺癌灶的ADC值,采用Pearson相关分析检验癌灶ADC值与前列腺癌根治术标本Gleason评分的相关性,以及穿刺活检所得Gleason评分与前列腺癌根治术标本Gleason评分的相关性,采用ROC曲线分析确定癌灶ADC值和穿刺活检所得Gleason评分区分前列腺低级别癌和中高级别癌的效能.结果 前列腺穿刺活检评估前列腺癌根治术标本Gleason评分的准确率为41.2％ (21/51),11.8％ (6/51)患者Gleason评分被高估,47.0％ (24/51)患者GS被低估.51例患者前列腺癌灶的ADC值平均为(0.974±0.194)×10-3 mm2/s,35例中高级别前列腺癌平均ADC值为(0.907±0.160)×10-3 mm2/s,16例低级别前列腺癌平均ADC值为(1.121±0.185)×10-3 mm2/s.前列腺癌灶ADC值与前列腺癌根治术标本Gleason评分存在负相关性(r=-0.761,P＜0.01),而穿刺活检所得Gleason评分与前列腺癌根治术标本Gleason评分不存在相关性(r=0.187,P=0.189).ADC值和穿刺活检所得Gleason 评分区分前列腺低级别癌和中高级别癌的ROC曲线下面积分别为0.827和0.689.结论 前列腺癌灶的ADC值预测前列腺癌侵袭性优于穿刺活检所得Gleason评分.     

Diffusion weighted fMRI at 1.5 T

Functional magnetic resonance imaging (fMRI) is capable of detecting task-induced blood oxygenation changes using susceptibility sensitive pulse sequences such as gradient-recalled echo-planar imaging (EPI). The local signal increases seen in the time course are believed to be due to an increase in oxygen delivery that is incommensurate with oxygen demands. To help isolate the sources of functional signal changes, the authors have incorporated various forms of diffusion weighting Into EPI pulse sequences to characterize the apparent mobility of the functionally modulated protons. Results suggest that the majority of the functional signal at 1.5 T arises from protons that have apparent diffusion coefficients that are approximately four or five times higher than that of brain tissue. This implies that significant functional signal sources are either protons within the vascular space or protons from the perivascular space that is occupied by cerebro-spinal fluid.     

Clinical advantages of 3.0 T MRI over 1.5 T

Since approval by the FDA in 2000, human MR imaging (MRI) at 3.0 T has been increasingly used in clinical practice. In spite of the potential technical challenges, a number of clinical advantages of 3.0 T MRI over 1.5 T have been identified in the recent years. This article reviews the benefits and the current knowledge of 3.0 T whole-body MRI from an evidence-based perspective and summarizes its clinical applications.     

T2 quantitation of articular cartilage at 1.5 T

PURPOSE: To evaluate sources of error when using a multiecho sequence for quantitative T2 mapping of articular cartilage at 1.5 T. MATERIALS AND METHODS: Phantom measurements were used to assess the contribution of stimulated echoes to inaccuracy of T2 measurements in cartilage using a multiecho sequence. Five volunteer studies compared in vivo single-echo spin echo results to multiecho, single-slice and multiecho, multislice acquisitions for assessment of both the stimulated echo and magnetization transfer contrast (MTC) contributions to T2 measurement inaccuracy. RESULTS: Phantom experiments demonstrated that substantial inaccuracy (10%-13% longer T2 values) is introduced from stimulated echoes with a multiecho sequence with slice-selective refocusing pulses. The in vivo volunteer studies also demonstrated increases in measured T2 by up to 48% with a multiecho sequence. Use of the multiecho sequence in the multislice mode resulted in T2 values closer to the single-echo standards for the volunteer studies. However, this apparent increased accuracy should be regarded as circumstantial, as it only occurs because the error due to MTC has the opposite sign compared to the error due to the stimulated echo contribution. CONCLUSION: Use of a multiecho, multislice sequence for cartilage T2 measurements should be undertaken with the caution that substantial inaccuracy is introduced from stimulated echoes and MTC.     

Osteopetrosis: MR characteristics at 1.5 T

Four patients with proved osteopetrosis (three with the infantile malignant form and one with the benign form) were examined with magnetic resonance imaging at 1.5 T. All patients were studied in the coronal and sagittal planes using both short and long repetition time/echo time sequences. The infantile malignant form was characterized by a complete lack of signal from the marrow alternating with a signal intensity equivalent to that of the intervertebral disks, resulting in a "stepladder" appearance. In the benign form or after successful marrow transplantation in the infantile malignant form, intermediate or high signal intensity in the vertebrae was noted, suggesting the presence of some marrow elements.     

Three-dimensional T1rho-weighted MRI at 1.5 Tesla

PURPOSE: To design and implement a magnetic resonance imaging (MRI) pulse sequence capable of performing three-dimensional T(1rho)-weighted MRI on a 1.5-T clinical scanner, and determine the optimal sequence parameters, both theoretically and experimentally, so that the energy deposition by the radiofrequency pulses in the sequence, measured as the specific absorption rate (SAR), does not exceed safety guidelines for imaging human subjects. MATERIALS AND METHODS: A three-pulse cluster was pre-encoded to a three-dimensional gradient-echo imaging sequence to create a three-dimensional, T(1rho)-weighted MRI pulse sequence. Imaging experiments were performed on a GE clinical scanner with a custom-built knee-coil. We validated the performance of this sequence by imaging articular cartilage of a bovine patella and comparing T(1rho) values measured by this sequence to those obtained with a previously tested two-dimensional imaging sequence. Using a previously developed model for SAR calculation, the imaging parameters were adjusted such that the energy deposition by the radiofrequency pulses in the sequence did not exceed safety guidelines for imaging human subjects. The actual temperature increase due to the sequence was measured in a phantom by a MRI-based temperature mapping technique. Following these experiments, the performance of this sequence was demonstrated in vivo by obtaining T(1rho)-weighted images of the knee joint of a healthy individual. RESULTS: Calculated T(1rho) of articular cartilage in the specimen was similar for both and three-dimensional and two-dimensional methods (84 +/- 2 msec and 80 +/- 3 msec, respectively). The temperature increase in the phantom resulting from the sequence was 0.015 degrees C, which is well below the established safety guidelines. Images of the human knee joint in vivo demonstrate a clear delineation of cartilage from surrounding tissues. CONCLUSION: We developed and implemented a three-dimensional T(1rho)-weighted pulse sequence on a 1.5-T clinical scanner.     

MR evaluation of adrenal masses at 1.5 T

We retrospectively studied the value of MR imaging at 1.5 T to distinguish between nonadenomatous (n = 17) and adenomatous (n = 15) adrenal masses on the basis of (1) signal-intensity ratios on T1- and T2-weighted spin-echo images, (2) T2 relaxation times, and (3) T2 relaxation-time ratios. Univariate and then multivariate logistic regression were applied to these quantitative parameters to determine which of these best discriminated nonadenomas from adenomas, and whether or not more than one of these parameters improved the prediction. The adrenal mass/liver signal-intensity ratio on T2-weighted spin-echo images could not be used to differentiate nonadenomas from adenomas. Adrenal mass/fat signal-intensity ratios on T2-weighted spin-echo images, adrenal/liver T2 relaxation-time ratios, and adrenal mass T2 relaxation times were best for distinguishing nonadenomas from adenomas. By using a T2 value of greater than 61 msec, the true-positive ratio/false-positive ratio of differentiating nonadenomas from adenomas was 100%/20%; at greater than 82 msec, it was 64%/0.06%. The adrenal mass/fat signal-intensity ratios on T2-weighted spin-echo images and the adrenal/liver T2 relaxation-time ratios showed similar inherent discriminatory capacity. Overlap remains despite the use of these parameters. On the basis of this preliminary information, we conclude that MR has merit for the characterization of adrenal masses at 1.5 T. T2 relaxation time of the adrenal mass shows the greatest promise for discriminating nonadenomas from adenomas.     

MR imaging of the larynx at 1.5 T

The normal magnetic resonance (MR) anatomy of the larynx at high field strength (1.5 T) was studied in 2 normal excised larynges and 62 subjects without laryngopharyngeal disease. The two normal excised larynges were imaged using a 1.5 T MR scanner with a 3 in diameter circular surface coil and a GE 9800 CT scanner. The larynges were sectioned transversely and the MR and CT images compared to gross and histologic sections. Unossified hyaline cartilage was intermediate in signal intensity on T1-weighted and proton density images and low in intensity on T2-weighted images. The signal intensity from ossified cartilage was determined by the amount of fatty marrow and was high in intensity on T1-weighted and proton density images and low to intermediate in intensity on T2-weighted images. A chemical shift artifact from high intensity fatty marrow obscured the calcified or ossified cortex of the major laryngeal cartilages along the frequency encoding axis. The epiglottic cartilage demonstrated an intermediate signal intensity on T1-weighted images and higher intensity on proton density and T2-weighted images. The intralaryngeal muscles were well demonstrated as low intensity structures. The conus elasticus and the vocal ligaments were not recognized as distinct structures. However, the quadrangular membrane and a previously undescribed membrane separating the preepiglottic and paralaryngeal spaces were shown on MR as low intensity linear structures. In the 62 subjects, MR at 1.5 T proved excellent for demonstrating the anatomical details of the major laryngeal cartilages, extra- and intralaryngeal muscles, ligaments, and soft tissues including the vocal cords, false vocal cords, laryngeal ventricles, aryepiglottic folds, preepiglottic space, and paralaryngeal spaces. Visibility and intensity of muscles, ligaments, and soft tissues did not depend on age or sex. The intensity pattern of the thyroid and cricoid cartilages demonstrated wide variations in the same sex and age groups, depending on the degree of ossification. However, they did show more high intensity foci in older men than in younger women. Magnetic resonance showed better contrast resolution and finer detail than CT scans in the same subjects. Magnetic resonance imaging at 1.5 T, with either a saddle-shaped neck surface coil or a 3 in diameter circular surface coil, provides high contrast and high spatial resolution images and could be useful for the diagnosis of lesions of the larynx.(ABSTRACT TRUNCATED AT 400 WORDS)     

MR-guided and MR-monitored neurosurgical procedures at 1.5 T

A combined MR suite and operating room (MR-OR) has been developed and extensively assessed for its use in a wide spectrum of therapeutic applications. Equipped with a 1.5 T short bore clinical MR scanner and standard neurosurgical OR equipment, in this MR surgical suite, surgeons can obtain intraoperative planar and volumetric MR images with superior soft tissue contrast and spatial resolution for surgical planning, guidance, and monitoring. Besides MR morphologic imaging capability, blood oxygen level-dependent functional MRI and proton MR spectroscopic imaging have been demonstrated intraoperatively in the same MR-OR to aid in surgical planning and guide tumor resections. A perspective surgical navigation device and remotely operated instrument have been developed and successfully used to assist surgeons in aligning and introducing biopsy needles under fluoroscopic MRI in brain biopsy procedures. Furthermore, surgical complications can be assessed immediately before the closure. There are numerous advantages offered by this unprecedented MR-guided surgical approach, most of which are demonstrated and presented herein. Since 1997, >270 neurosurgical cases (42% brain biopsies, 25% tumor resections, 11% functional neurosurgeries, 10% cyst drainages and shunt placements, and 12% others) have been performed in the MR-OR with a <1% overall complication rate. The tumor recurrence rate for the MR-guided surgical approach is significantly less than that of the conventional one. Exemplary neurosurgical cases that have been performed in the MR-OR suite within the last 24 months are included. Overall, this high magnetic field approach to the MR-guided minimally invasive surgical procedures has been shown to be practical and acceptable to neurosurgeons as well as to neuroradiologists for a wide range of neurosurgical and neuroradiologic applications.     

In vivo multiple-mouse imaging at 1.5 T.

A multiple-mouse solenoidal MR coil was developed for in vivo imaging of up to 13 mice simultaneously to screen for tumors on a 1.5 T clinical scanner. For the coil to be effective as a screening tool, it should permit acquisition of MRIs in which orthotopic tumors with diameters >2 mm are detectable in a reasonable period of time (<1 hr magnet time) and their sizes accurately measured. Using a spin echo sequence, we demonstrated that this coil provides sufficient sensitivity for moderately high resolution images (156-176 microm in plane-resolution, 1.5 mm slice thickness). This spatial resolution permitted detection of primary brain tumors in transgenic/knockout mice and orthotopic xenografts. Brain tumor size as measured by MRI was correlated with size measured by histopathology (P < 0.001). Metastatic tumors in the mouse lung were also successfully imaged in a screening setting. The multiple mouse coil is simple in construction and may be implemented without any significant modification to the hardware or software on a clinical scanner.