Dynamic contrast enhanced magnetic resonance imaging in monitoring bone metastases in breast cancer patients receiving bisphosphonates and endocrine therapy

Purpose: To study the role of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) in monitoring the response of bone metastases to endocrine therapy combined with bisphosphonates in patients with breast cancer.

Material and Methods: Ten breast cancer patients with bone metastases who were to receive endocrine therapy and bisphosphonates were investigated prospectively by DCE-MRI. We chose a reference lesion for each patient who was studied at baseline, within 3 weeks from the second administration of bisphosphonates, and after 4 and 8 months from the initiation of medical treatment. Time/intensity curves, representing temporal changes of signal intensity in areas of interest in the context of the target lesions (ROI), were obtained for each DCE-MRI.

Results: Changes in the shape of the T/I curves suggesting tumor regression were seen shortly after the initiation of medical treatment in the three patients who had the most durable responses.

Conclusion: DCE-MRI has the potential to detect early changes related to medical treatment in bone metastases from breast cancer. If confirmed in larger series, these data identify DCE-MRI as a diagnostic tool for evaluating new bone targeting antineoplastic agents.     

BI-RADS~-MRI4类乳腺癌阳性预测值与亚分类的初探

目的分析MRI的乳腺影像报告和数据系统(breast imaging reporting and data system,BI-RADS-MRI)4类病例乳腺癌阳性预测值(positive predictive value,PPV),初步探讨其亚分类。方法回顾性总结BI-RADS-MRI4类286例患者的MRI资料,以病理及随访结果为金标准,统计该类病例活检率及PPV,并用Logistic回归法分析各征象的PPV和优势比(OR)。结果 BI-RADS-MRI 4类活检率为75.5%,PPV为30.6%。不规则型肿块呈不均匀强化,平台型或流出型曲线的PPV为0.56;毛刺肿块,强化均匀的PPV为0.45;圆形/椭圆形肿块,边缘光滑,强化均匀的PPV为0.11。病灶呈导管/段样分布、不均匀强化的PPV为0.35;病灶呈局灶/区域/广泛分布、强化均匀的PPV为0.22。结论 PPV能初步对BI-RADS-MRI 4类行亚分类,但仍需进一步研究。     

Relationship between DCE-MRI morphological and functional features and histopathological characteristics of breast cancer

We studied whether dynamic contrast-enhanced MRI (DCE-MRI) could identify histopathological characteristics of breast cancer. Seventy-five patients with breast cancer underwent DCE-MRI followed by core biopsy. DCE-MRI findings were evaluated following the scoring system published by Fischer in 1999. In this scoring system, five DCE-MRI features, three morphological (shape, margins, enhancement kinetic) and two functional (initial peak of signal intensity (SI) increase and behavior of signal intensity curve), are defined by 14 parameters. Each parameter is assigned points ranging from 0 to 1 or 0 to 2, with higher points for those that are more likely to be associated with malignancy. The sum of all the points defines the degree of suspicion of malignancy, with a score 0 representing the lowest and 8 the highest degree of suspicion. Associations between DCE-MRI features and tumor histopathological characteristics assessed on core biopsies (histological type, grading, estrogen and progesterone receptor status, Ki67 and HER2 status) were studied by contingency tables and logistic regression analysis. We found a significant inverse association between the Fischer’s score and HER2-overexpression (odds ratio-OR 0.608, p = 0.02). Based on our results, we suggest that lesions with intermediate-low suspicious DCE-MRI parameters may represent a subset of tumor with poor histopathological characteristics. Filippo Montemurro and Laura Martincich contributed equally to this work.     

磁共振扩散加权成像联合动态增强评估乳腺导管内癌与乳腺浸润癌的比较研究

目的：探讨乳腺导管内癌（DCIS）与浸润癌（IC）在动态增强磁共振成像（DCE-MRI）和扩散加权成像（DWI）上的影像特征,提高其影像诊断水平。方法回顾性分析10例DCIS患者（病灶13个）及10例 IC患者（病灶10个）的DCE-M RI及DWI图像,分析病灶强化形态特征、时间信号强度曲线并定量分析 ADC值。结果依据强化形态特征：DCIS强化以非块样强化中的段样强化为主,IC强化以块样强化为主,两者间差异具有统计学意义。依据时间信号强度曲线：DCIS和IC均以流出型为主,无显著性差异。依据ADC值：DCIS的平均ADC值约为（1．036±0．25）×10^-3 mm^2/s , IC的平均ADC值约为（0．79±0．20）×10^-3 mm^2/s ,两者间差异具有统计学意义。结论结合病灶强化形态特征及ADC值,DCE-M RI联合DWI有助于乳腺导管内癌及浸润癌的鉴别诊断,提高影像诊断水平。     

乳腺浸润性导管癌不同分子分型及病理组织学分级间常规超声征像的差异

 目的 探讨乳腺浸润性导管癌不同分子分型及病理组织学分级间常规超声征像的差异。方法 收集因乳腺肿物入保定市第一中心医院诊疗并最终手术确诊为乳腺浸润性导管癌的患者资料,回顾性分析术前常规超声典型征像及术后病理学资料,比较不同分子分型及病理组织学分级间的超声征像差异及相关性。结果 (1)五组分子分型病灶的超声征像均存在统计学差异(P<0.05),其中三阴型多表现为肿物回声均匀(47.2%,17/36),病灶后方回声增强(58.3%,21/36);少表现为回声衰减(5.6%,2/36),微钙化(27.8%,10/36)等。HER-2阳性(HR阳性)多表现为微钙化(77.8%,35/45)伴病灶后方回声衰减(48.9%,22/45)。Luminal A型多表现乏血供(62.2%,46/74)。(2)不同组织学分级病灶的超声征像存在统计学差异(P<0.05)。中高分化组病灶多表现为边缘毛刺征(70.0%,133/190),高回声晕(60.5%,115/190),病灶后方回声衰减(42.1%,80/190);低分化组病灶超声征像多表现为富血供(84.3%,43/51)。多变量logistic回归分析显示,血流分布及肿块后方回声特点是超声影像学辨别低分化组IDC病灶的独立危险因素(P<0.05)。结论 乳腺浸润性导管癌的超声检查在一定程度上有助于辨别分子分型及组织学分级程度,为乳腺癌患者个性化治疗方案的选择及预后提供影像学依据。     

3.0TDCE-MRI对宫颈癌的评估价值

目的：探讨3.0T 动态增强磁共振(DCE-MRI)对宫颈癌各组特征的评估价值。方法156例宫颈癌患者在治疗前行常规 MRI 及 DCE-MRI 扫描,在获得病理结果后将宫颈癌患者分成6组(组织学类型,分化程度,FIGO 早晚分期,淋巴结状态,肿瘤直径,年龄段)计算时间-信号强度曲线半定量参数,并利用 SPSS 及 R3.1.1软件进行统计学分析。结果鳞癌注射对比剂后30 s 的强化率(SI30s%)及最大增强斜率(Slope)均高于腺癌,FIGO 早期宫颈癌的达峰时间(TTP)低于 FIGO 晚期宫颈癌,FIGO 早期宫颈癌的 Slope 高于 FIGO 晚期宫颈癌,其余各项分组的各参数之间无明显统计学差异。结论3.0T DCE-MRI 的半定量参数可以有效鉴别宫颈鳞癌与腺癌及 FIGO 早/晚分期宫颈癌,利用 Slope 鉴别宫颈鳞癌与腺癌的价值高于 SI30s%,TTP 与 Slope 鉴别 FIGO早/晚分期宫颈癌的价值相当。     

Magnetic resonance imaging evaluation of residual ductal carcinoma in situ following preoperative chemotherapy in breast cancer patients

Objectives

To retrospectively evaluate the ability of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) in helping to distinguish between lesions with and without residual ductal carcinoma in situ (DCIS) in patients showing no residual invasive cancer after preoperative chemotherapy.

Methods

DCE-MR images of 46 consecutive breast cancer patients (mean age, 47 years; range, 30–69 years) with no residual invasive cancer (15 had residual DCIS and 31 had no residual DCIS) following preoperative chemotherapy and surgery were blindly reviewed and categorized by two radiologists in consensus. Thereafter, DCE-MRI findings that could be helpful in distinguishing lesions with and without residual DCIS were analyzed.

Results

When any enhancement was present, 93% (14 of 15) sensitivity and 35% (11 of 31) specificity for the detection of residual DCIS on post-chemotherapy MRI were achieved. Although 65% (20 of 31) of lesions without residual cancer had some enhancing findings, the lesion to fibroglandular signal intensity ratio showed 86.7% (13 of 15) sensitivity and 83.9% (26 of 31) specificity with an Az value of 0.854 (95% confidence interval: 0.718, 0.940) when a cut-off point of a ratio of 1.34 was used.

Conclusion

DCE-MRI has the potential in distinguishing between lesions with and without residual DCIS in patients showing no invasive cancer after preoperative chemotherapy.     

Factor analysis in thallium-201 chloride thyroid studies

Factor analysis was applied to thyroid thallium-201 imaging to get separated image of tumor from normal thyroid tissue. Thirty-eight patients with various thyroid tumors which were histologically confirmed were included in this study. Following intravenous injection of 111 MBq (3 mCi) of 201Tl chloride, thyroid images in 64 frames were taken for 30 to 60 minutes using Toshiba gamma camera system and data were analyzed by 2 or 3 factor analysis. In 28 of 38 patients separated images of the lesions from normal thyroid were obtained and time-activity curves of various shapes corresponding to the lesions were also obtained. When the curves were classified into 3 groups according to their shapes: increasing, flat and decreasing, follicular carcinoma did not show increasing shape whilst neither of papillary carcinoma, squamous cell carcinoma and anaplastic carcinoma showed decreasing shape. The shapes of the curves were thought to be reflected in clearance of the agent from the lesions. Factor analysis in 201Tl chloride thyroid scan provided separated image of tumor from normal thyroid gland automatically and the obtained curves corresponding to the lesions provided information for estimating the characteristics of thyroid tumors.     

Clinical application of bilateral high temporal and spatial resolution dynamic contrast-enhanced magnetic resonance imaging of the breast at 7 T

Objective

The objective of our study was to evaluate the clinical application of bilateral high spatial and temporal resolution dynamic contrast-enhanced magnetic resonance imaging (HR DCE-MRI) of the breast at 7 T.

Methods

Following institutional review board approval 23 patients with a breast lesion (BIRADS 0, 4–5) were included in our prospective study. All patients underwent bilateral HR DCE-MRI of the breast at 7 T (spatial resolution of 0.7 mm³ voxel size, temporal resolution of 14 s). Two experienced readers (r1, r2) and one less experienced reader (r3) independently assessed lesions according to BI-RADS®. Image quality, lesion conspicuity and artefacts were graded from 1 to 5. Sensitivity, specificity and diagnostic accuracy were assessed using histopathology as the standard of reference.

Results

HR DCE-MRI at 7 T revealed 29 lesions in 23 patients (sensitivity 100 % (19/19); specificity of 90 % (9/10)) resulting in a diagnostic accuracy of 96.6 % (28/29) with an AUC of 0.95. Overall image quality was excellent in the majority of cases (27/29) and examinations were not hampered by artefacts. There was excellent inter-reader agreement for diagnosis and image quality parameters (κ?=?0.89–1).

Conclusion

Bilateral HR DCE-MRI of the breast at 7 T is feasible with excellent image quality in clinical practice and allows accurate breast cancer diagnosis.

Key points

? Dynamic contrast-enhanced 7-T MRI is being developed in several centres. ? Bilateral high resolution DCE-MRI of the breast at 7 T is clinically applicable. ? 7-T HR DCE-MRI of the breast provides excellent image quality. ? 7-T HR DCE-MRI should detect breast cancer with high diagnostic accuracy.     

Dynamic MRI and CAD vs. Choline MRS: Where is the detection level for a lesion characterisation in prostate cancer?

Purpose: To evaluate the role of pre-interventional fused high resolution T2-weighted images with parametrically analysed dynamic contrast enhanced T1-weighted magnetic resonance (MR) images (DCE-MRI) and 1H magnetic resonance spectroscopy (MRS) for a precise biopsy for the detection of prostate cancer and for the delineation of intraprostatic subvolumes for intensity modulated radiation therapy (IMRT).

Materials and methods: Inclusion criteria: Pathological prostate-specific antigen values (PSA) and/or previously negative transrectal ultrasound guided biopsy. Standardised biopsy of the prostate divided into 20 regions. Image fusion of coloured parametric maps derived from DCE-MRI and MRS (single voxel spectroscopy, SVS; chemical shift imaging, CSI) with T2 images for morphological localisation using the MR-workstation, a separate CAD-workstation (CAD: computer aided diagnosis) or a radiation treatment planning system. Correlation of these intraprostatic subvolumes with histology and cytokeratin-positive areas in prostatectomy species.

Results: DCE-MRI: Sensitivity 82%, specificity 89%, accuracy 88%, positive predictive value 61%, negative predictive value 96%. SVS: Sensitivity 55%, specificity 62%. CSI: Sensitivity 68%, specificity 67%. False positive findings due to prostatitis, adenomatous hyperplasia, false negative findings due to low signal (PIN (prostatic intraepithelial neoplasia), cut-off level for DCE-MRI: lesions smaller 3 mm and less than 30% cancer cells, for SVS: lesions smaller 8 mm and less than 50% cancer cells), for CSI: lesions smaller 4 mm and less than 40% cancer cells. Our MR data are correlated with published choline PET/CT data (PET/CT: hybrid scanner of positron emission tomography and computed tomography).

Conclusions: DCE-MRI and MRS are helpful for a precise biopsy of the prostate. The European Society for Therapeutic Radiology and Oncology (ESTRO) guidelines 2006 for radiation treatment planning of the prostate have to be revised, if the standardised biopsy will be replaced by a lesion-orientated biopsy. Until now it is unclear, if the parametric maps of DCE-MRI and MRS can be used for radiation treatment planning of the prostate.     

Characterization of benign and malignant breast lesions with computed tomography laser mammography (CTLM): initial experience

OBJECTIVES: The aim of this study was to characterize benign and malignant breast lesions with computed tomography-laser mammography (CTLM). MATERIALS AND METHODS: In a prospective study, 100 female patients with 105 breast lesions classified as BIRADS IV to V at mammography underwent mammography, CTLM, and histologic verification at our institution. CTLM images were analyzed by radiologists with knowledge of the lesion's position but who were blinded to histology and morphologic findings from mammography. Two radiologists independently evaluated whether there was increased absorption, a sign of malignancy, on CTLM and assessed the appearance (volumes or linear branching) and shape (round or irregular) of the lesions. RESULTS: Histologic analysis revealed 55 benign (52.4%) and 50 malignant (47.6%) breast lesions. Increased absorption was observed significantly more often in malignant than in benign lesions (70.0% vs. 32.7%, P = 0.028). Invasive cancer showed increased absorption in 76.2%, and ductal carcinoma in situ in 37.5%. Common morphologic characteristics of increased absorption were "volumes" (85.7% of malignant and 77.8% of benign lesions) with round shape (78.1% of malignant and 73.3% of benign lesions). CONCLUSION: Our data indicate that CTLM, when used as an adjunct to mammography, may provide additional information to characterize benign and malignant breast lesions.     

三阴性乳腺癌X线征象及临床病理分析

目的：探讨三阴性乳腺癌(TNBC)的 X 线表现,提高对其诊断水平。方法收集经病理学及免疫组化证实的 TNBC 105例,分析 X 线表现及临床病理。结果(1)TNBC 中主要病理类型为浸润性导管癌(64例,61.0%),其次为髓样癌(24例,22.9%)。(2)本组 TNBC 的 X 线征象主要表现为肿物(82例,78.1%),其中边缘清晰者占46.3%;肿物合并钙化者占24.4%。(3)本组 TNBC患者中出现钙化者少见,分布主要表现为区域性或簇状,而形态以恶性及可疑恶性钙化为主。(4)本组 TNBC 中浸润性导管癌与髓样癌的 X 线征象,在肿瘤的形态、边缘差异有统计学意义(P <0.05)。结论(1)TNBC X 线表现为边缘清晰的类圆形肿物。(2)髓样癌在 TNBC 中所占比例较大,其 X 线表现为边缘清晰肿物。(3)TNBC 较少发生钙化,钙化形态主要表现为可疑恶性及恶性。     

乳腺黏液腺癌MRI表现特征及其与病理对照研究

目的 探讨乳腺黏液腺癌MR平扫、动态增强(DCE)及DWI表现特征及其与病理表现的相关性.方法 MR枪查采用1.5 T MR扫描仪及乳腺专用线圈,包括MR平扫、3D DCE-MRI以及b值分别为500和1000 s/mm2的DWI.对8例行乳腺MR检查并经手术病理证实的乳腺黏液腺癌,依据乳腺影像报告和数据系统(BI-RADS)MRI标准,回顾性分析病变形态学、T1WI及T2WI信号强度、肿块内部强化特征及动态增强曲线类型、DWI上ADC值表现,并与病理对照,乳腺黏液腺癌病理诊断依据2003年WHO乳腺肿瘤病理学标准.结果 8例乳腺黏液腺癌(5例单纯黏液腺癌,3例混合型黏液腺癌)的黏液含昔为60%～90%.8例在MRI上均表现为肿块,平扫T1WI呈低信号,T2WI呈高和明显高信号.动态增强后,1例表现为不均匀轻微强化,2例表现为内部欠均匀的渐进性强化,其余5例于动态增强早期时相均表现为边缘明显强化,肿块内部结构呈渐进性强化,强化方式呈由边缘强化向中心渗透趋势.于DWI上病变均表现为明显高信号,平均ADC值在b值500 s/mm2时为(2.41±0.28)×10-3mm2/s,b值1000 s/mm2时为(2.06±0.14)×10-3mm2/s,分别高于正常乳腺组织的(1.71±0.32)×10-3和(1.43±0.24)×10-3mm2/s.结论 乳腺黏液腺癌在MR平扫T2WI、DEC及DWI表现均不同于常见的浸润性导管癌,这些特征性表现反映了其特殊的病理类型,MR多种成像序列相结合可对乳腺黏液腺癌在术前作出正确诊断.     

Combined morphological, [1H]-MR spectroscopic and contrast-enhanced imaging of human prostate cancer with a 3-Tesla scanner: preliminary experience

PURPOSE: The objective of this study was to explore the feasibility of combined morphological magnetic resonance imaging (MRI), [(1)H]magnetic resonance spectroscopic imaging (MRSI) and quantitative dynamic contrast-enhanced MRI (DCE-MRI) of human prostate cancer at 3 Tesla using a pelvic phased-array coil. MATERIALS AND METHODS: MRI, MRSI and DCE-MRI with a 3-Tesla whole-body scanner were performed in 30 patients with biopsy-proven prostate cancer before radical prostatectomy. High-resolution T2-weighted turbo spin echo (TSE) images were evaluated for visualisation of the peripheral zone, central gland, visibility of the cancer lesion, prostatic capsule delineation and overall image quality according to a five-point scale. Relative levels of the prostate metabolites citrate, choline and creatine were determined in cancer and in the normal peripheral zone (PZ) and central gland (CG). Spectra were also evaluated for the separation of the signal of citrate, choline and creatine and suppression of lipid and water signals. Time-intensity curves were obtained for prostatic cancer and healthy PZ and CG from DCE-MRI. Finally, time of arrival, time to peak, maximum enhancement and wash-in rate in cancer, normal PZ and CG were calculated. RESULTS: The high signal-to-noise ratio (SNR) at 3 Tesla provided T2-weighted TSE images with excellent anatomical detail (in-plane voxel size of 0.22 x 0.22 mm) and good T2 contrast. The increased spectral resolution was sufficient to separate the choline and creatine resonances and allow delineation of the four peaks of citrate resonance. The (choline + creatine)/citrate ratio was elevated in cancer in comparison with PZ and CG (p<0.001). Dynamic contrast-enhanced images showed good temporal resolution. All parameters obtained from DCE-MRI showed a statistically significant (P<0.05) difference between cancer tissue and normal PZ and CG. Wash-in rate and (choline+creatine)/citrate ratio were significantly correlated (r=0.713, P=0.001) in PZ cancer, whereas the correlation was not significant (r=0.617, P=0.06) in CG and in PZ (r=0.530, P=0.08). CONCLUSIONS: It is possible to perform MRI of prostate cancer at 3 Tesla using a pelvic phased-array coil with high spatial, temporal and spectral resolution. The combination of vascular information from DCE-MRI and metabolic data from MRSI has excellent potential for improved accuracy in delineating and staging prostate carcinoma. These results suggest that high magnetic field strengths offer the possibility of studying prostate cancer without use of an endorectal coil.     

DCE-MRI和DWI对乳腺腺病和乳腺癌的诊断价值

目的 探讨动态增强磁共振成像(DCE-MRI)和扩散加权成像(DWI)对乳腺腺病和乳腺癌的诊断价值.方法 回顾性分析手术后病理证实的30例乳腺腺病和45例乳腺癌的MRI影像资料,包括病灶的形状、边缘、强化方式、T2WI信号特点、时间-信号强度曲线(TIC)类型、早期强化率(EER)、达峰时间、背景强化程度及病灶的表观扩散系数(ADC)值.结果 在形态学特征中,乳腺癌多表现为边缘不规则,伴或不伴有毛刺,差异有统计学意义(P=0.002);同时多表现为不均匀强化,差异有统计学意义(P=0.009).在动态强化特征上,乳腺癌多表现为TIC流出型,EER多表现为快速流入,达峰时间多在2 min以内,以上差异均有统计学意义(P<0.001).在ADC值上,乳腺癌为(1.03±0.24)×10-3mm2/s,低于乳腺腺病的(1.34±0.30)×10-3mm2/s,差异有统计学意义(P<0.001).乳腺腺病和乳腺癌的形状特点、T2WI信号特点、背景强化程度比较差异无统计学意义(P>0.05).结论 DCE-MRI和DWI联合应用对于鉴别诊断乳腺腺病和乳腺癌具有重要的价值.     

乳腺浸润性导管癌超声影像特征分析

 目的 分析超声各特征性影像表现在乳腺浸润性导管癌中的诊断价值。方法 选取解放军总医院第六医学中心 2018-01至2019-12两年内收治的 135例乳腺浸润性导管癌患者纳入本研究,分析乳腺浸润性导管癌的超声影像特征、体检自检发现率以及淋巴结转移与病变大小、位置的相关性。结果 (1)单因素分析显示:形态不规则(91.11%)、边界不清楚(64.44％)、血流信号(44.44％)、微钙化(37.78%)、纵横比＞1(17.78％)、后方回声衰减(15.56％)超声诊断指标,与浸润性导管癌的诊断具有相关性;(2)与其他三个象限相比较,内上象限浸润性导管癌更容易被患者自检发现,占自检发现病例的34.93%;(3)内上象限及外上象限的浸润性导管癌更容易发生淋巴结转移(转移率为:内上:25.53%,内下:0.00%,外上:64.70%,外下:11.76%);(4)对＜3 cm的浸润性导管癌,其大小与腋窝淋巴结的转移没有相关性。结论 超声表现以形态不规则在乳腺浸润性导管癌中的发生率最高,且在早期病变中即表现出来;乳腺病变的自检检出率、乳腺癌淋巴转移率均与乳腺病变的大小和位置密切相关。     

Dynamic contrast-enhanced magnetic resonance imaging of human melanoma xenografts with necrotic regions

PURPOSE: To investigate whether high-resolution images of necrotic regions in tumors can be derived from gadopentetate dimeglumine (Gd-DTPA)-based dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) series. MATERIALS AND METHODS: E-13 human melanoma xenografts were used as preclinical models of human cancer. DCE-MRI was performed at a voxel size of 0.23 x 0.47 x 2.0 mm3 with the use of spoiled gradient recalled sequences. Tumor images of E . F (E is the initial extraction fraction of Gd-DTPA and F is blood perfusion) and lambda (the partition coefficient of Gd-DTPA, which is proportional to extracellular volume fraction) were produced by subjecting DCE-MRI series to Kety analysis, and these images were compared with histological preparations from the imaged slices. RESULTS: Strong correlations were found between fraction of necrotic tissue and fraction of voxels with lambda > lambdaL for lambdaL values of 0.4 to 0.6. Binary lambda images differentiating between lambda values > lambdaL and lambda values < lambdaL were found to mirror necrotic regions well in tumors with large necroses. However, necrotic foci that were small compared with the voxel size were not detectable. CONCLUSION: Clinically relevant images of necrotic tumor regions can be obtained for E-13 melanomas by subjecting Gd-DTPA-based DCE-MRI series to Kety analysis.     

Assessment of tumor blood perfusion by high-resolution dynamic contrast-enhanced MRI: a preclinical study of human melanoma xenografts.

A noninvasive method to obtain high-resolution images of tumor blood perfusion is needed for individualized cancer treatments. In this study we investigated the potential usefulness of dynamic contrast-enhanced MRI (DCE-MRI), using human melanoma xenografts as models of human cancer. Gadopentetate dimeglumine (Gd-DTPA) was used as the contrast agent, and DCE-MRI was performed at a voxel size of 0.5 x 0.2 x 2.0 mm3 with spoiled gradient-recalled sequences. We obtained images of E. F (where E is the extraction fraction, and F is perfusion) by subjecting DCE-MR images to Kety analysis. We obtained highly reproducible E. F images, which we verified by imaging heterogeneous tumors twice. We hypothesized that the extraction fraction of Gd-DTPA would be high and would not vary significantly in tumor tissue, implying that E. F should be a well-suited parameter for describing tumor blood perfusion. Observations consistent with this hypothesis were made by comparison of E. F-images with immunostained histological preparations from the imaged sections. The E. F images mirrored the histological appearance of the tumor tissue perfectly. Quantitative studies showed that E. F was highest in nonhypoxic tissue with high microvascular density, second highest in nonhypoxic tissue with low microvascular density, third highest in hypoxic tissue, and lowest in necrotic tissue. Moreover, the radial heterogeneity in E. F was almost identical to that in the blood supply, as assessed by the use of Na99mTcO4 as a perfusion tracer. Taken together, our observations show that high-resolution images reflecting tumor blood perfusion can be obtained by DCE-MRI.     

ADC mapping of benign and malignant breast tumors.

PURPOSE: The purpose of this study was to investigate the utility of diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC) value in differentiating benign and malignant breast lesions and evaluating the detection accuracy of the cancer extension. MATERIALS AND METHODS: We used DWI to obtain images of 191 benign and malignant lesions (24 benign, 167 malignant) before surgical excision. The ADC values of the benign and malignant lesions were compared, as were the values of noninvasive ductal carcinoma (NIDC) and invasive ductal carcinoma (IDC). We also evaluated the ADC map, which represents the distribution of ADC values, and compared it with the cancer extension. RESULTS: The mean ADC value of each type of lesion was as follows: malignant lesions, 1.22+/-0.31 x 10(-3) mm2/s; benign lesions, 1.67+/-0.54 x 10(-3) mm2/s; normal tissues, 2.09+/-0.27 x 10(-3) mm2/s. The mean ADC value of the malignant lesions was statistically lower than that of the benign lesions and normal breast tissues. The ADC value of IDC was statistically lower than that of NIDC. The sensitivity of the ADC value for malignant lesions with a threshold of less than 1.6 x 10(-3) mm2/s was 95% and the specificity was 46%. A full 75% of all malignant cases exhibited a near precise distribution of low ADC values on ADC maps to describe malignant lesions. The main causes of false negative and underestimation of cancer spread were susceptibility artifact because of bleeding and tumor structure. Major histologic types of false-positive lesions were intraductal papilloma and fibrocystic diseases. Fibrocystic diseases also resulted in overestimation of cancer extension. CONCLUSIONS: DWI has the potential in clinical appreciation to detect malignant breast tumors and support the evaluation of tumor extension. However, the benign proliferative change remains to be studied as it mimics the malignant phenomenon on the ADC map.     

磁共振DWI及动态增强扫描在前列腺疾病诊断中的价值

目的探讨磁共振扩散加权成像(DWI)和动态增强扫描(DCE-MRI)在前列腺疾病中的诊断价值。方法经穿刺活检或手术病理证实的20例前列腺癌及31例前列腺增生(BPH)患者进行了MR常规扫描、DWI和DCE-MRI扫描,测量病变的表观扩散系数(ADC)值,观察病灶常规MRI、DWI和动态增强MRI特征,绘制信号强度-时间曲线(SI-T曲线),SI-T曲线分成3型:Ⅰ型为信号强度早期增高后仍持续增高;Ⅱ型为信号强度早期增高后出现平台期;Ⅲ型为信号强度早期增高后出现下降期。经方差分析比较不同组织和病灶间差异。结果经DCE-MRI检查,20例前列腺癌患者中17例病灶区呈Ⅲ型曲线,2例呈Ⅱ型曲线,1例呈Ⅰ型曲线;31例前列腺增生患者中26例呈Ⅰ型曲线,4例呈Ⅱ型曲线,1例呈Ⅲ型曲线。前列腺癌组与BPH组的SI-T曲线类型分布的差异有统计学意义(P<0.01)。20例前列腺癌病灶于DWI上为高信号,于ADC图上呈明显低信号,ADC值为(1.18±0.08)×10-3 mm2/s,未被癌组织侵及的外围叶于DWI、ADC图上均呈等信号,ADC值为(2.67±0.09)×10-3 mm2/s;31例前列腺增生患者中央叶和外围叶于DWI、ADC图上均呈等信号,ADC值分别为(1.87±0.07)×10-3 mm2/s、(2.64±0.11)×10-3mm2/s。除前列腺增生的外围叶与未被癌组织侵及的外围叶之间差异无统计学意义(P>0.05)外,前列腺增生、前列腺癌、前列腺增生的外围叶和未被癌组织侵及的外围叶各组之间差异均有统计学意义(P<0.05)。DCE-MRI和DWI联合应用在前列腺癌诊断的敏感度、特异度和准确度均达80%以上。结论 DCE-MRI、DWI在前列腺癌和前列腺增生中具有特征性影像学表现,2种方法联合应用提高了MRI诊断前列腺癌的诊断和分期准确率。