Prostate cancer detection with 3 T MRI: Comparison of diffusion‐weighted imaging and dynamic contrast‐enhanced MRI in combination with T2‐weighted imaging

Purpose:

To evaluate the diagnostic ability of diffusion‐weighted imaging (DWI) and dynamic contrast‐enhanced imaging (DCEI) in combination with T2‐weighted imaging (T2WI) for the detection of prostate cancer using 3 T magnetic resonance imaging (MRI) with a phased‐array body coil.

Materials and Methods:

Fifty‐three patients with elevated serum levels of prostate‐specific antigen (PSA) were evaluated by T2WI, DWI, and DCEI prior to needle biopsy. The obtained data from T2WI alone (protocol A), a combination of T2WI and DWI (protocol B), a combination T2WI and DCEI (protocol C), and a combination of T2WI plus DWI and DCEI (protocol D) were subjected to receiver operating characteristic (ROC) curve analysis.

Results:

The sensitivity, specificity, accuracy, and area under the ROC curve (Az) for region‐based analysis were: 61%, 91%, 84%, and 0.8415, respectively, in protocol A; 76%, 94%, 90%, and 0.8931, respectively, in protocol B; 77%, 93%, 89%, and 0.8655, respectively, in protocol C; and 81%, 96%, 92%, and 0.8968, respectively in protocol D. ROC analysis revealed significant differences between protocols A and B (P = 0.0008) and between protocols A and D (P = 0.0004).

Conclusion:

In patients with elevated PSA levels the combination of T2WI, DWI, DCEI using 3 T MRI may be a reasonable approach for the detection of prostate cancer. J. Magn. Reson. Imaging 2010;31:625–631. © 2010 Wiley‐Liss, Inc.     

Value of MRI texture analysis for predicting high-grade prostate cancer

PurposeTo explore the potential value of MRI texture analysis (TA) combined with prostate-related biomarkers to predict high-grade prostate cancer (HGPCa).Materials and methodsEighty-five patients who underwent MRI scanning, including T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) prior to trans-rectal ultrasound (TRUS)-guided core prostate biopsy, were retrospectively enrolled. TA parameters derived from T2WI and DWI, prostate-specific antigen (PSA), and free PSA (fPSA) were compared between the HGPCa and non-high-grade prostate cancer (NHGPCa) groups using independent Student's t-test and the Mann-Whitney U test. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed to assess the predictive value for HGPCa.ResultsUnivariate analysis showed that PSA and entropy based on apparent diffusion coefficient (ADC) map differed significantly between the HGPCa and NHGPCa groups and showed higher diagnostic values for HGPCa (area under the curve (AUC) = 82.0% and 80.0%, respectively). Logistic regression and ROC curve analyses revealed that kurtosis, skewness and entropy derived from ADC maps had diagnostic power to predict HGPCa; when the three texture parameters were combined, the area under the ROC curve reached the maximum (AUC = 84.6%; 95% confidence interval (CI): 0.758, 0.935; P = 0.000).ConclusionTA parameters derived from ADC may be a valuable tool in predicting HGPCa. The combination of specific textural parameters extracted from ADC map may be additional tools to predict HGPCa.     

Multiparametric MRI of the prostate with three functional techniques in patients with PSA elevation before initial TRUS-guided biopsy

Objective:

Multiparametric MRI (mp-MRI) of the prostate is increasingly being used for local staging and detection of recurrence of prostate cancer (PCA). In patients with elevated prostate-specific antigen (PSA), mp-MRI could provide information on the position of the cancer, allowing adjustments to be made to the needle depth and direction before repeat transrectal ultrasound (TRUS)-guided biopsy to ensure accurate sampling of lesions. The purpose of the prospective study was to evaluate mp-MRI of the prostate in patients with PSA elevation before initial TRUS-guided biopsy.

Methods:

mp-MRI was performed in 94 patients using a 1.5-T scanner (MAGNETOM Aera^®; Siemens Healthcare, Erlangen, Germany) and 16-channel phased-array body coil (Siemens Healthcare). T₂ weighted images (T2WI), diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE) MRI and MR spectroscopy were obtained. TRUS-guided random biopsies and additional targeted biopsies of suspicious MRI areas were performed.

Results:

Additional targeted biopsies were obtained in 17 of 43 (40%) patients with PCA. 11 of 17 targeted biopsies contained PCA. 5 of 11 PCAs were diagnosed only by additional targeted biopsies. Sensitivity of mp-MRI in patients was 97.7% and specificity was 11.8%. mp-MRI was false negative in one patient. Sensitivity of mp-MRI in 207 lesions was 80.9% and specificity was 44.7%. In a logistic regression model, the apparent diffusion coefficient value was the only significant parameter to differentiate malignant and benign lesions.

Conclusion:

mp-MRI should be performed in patients with PSA elevation before initial TRUS-guided biopsy to allow additional targeted biopsies from suspicious areas of MRI. We recommend mp-MRI with T2WI, DWI, DCE MRI and MR spectroscopy. DWI as the most reliable technique should be used in every mp-MRI.

Advances in knowledge:

DWI is the most reliable technique in mp-MRI of the prostate.     

Prostate cancer recurrence after radical prostatectomy: the role of 3-T diffusion imaging in multi-parametric magnetic resonance imaging

Objectives

To validate the role of 3-T diffusion-weighted imaging (DWI) in the detection of local prostate cancer recurrence after radical prostatectomy (RP).

Methods

T2-weighted imaging, DWI and dynamic contrast-enhanced MRI (DCE-MRI) were performed with a 3-T magnet in 262 patients after RP. Twenty out of 262 patients evaluated were excluded. MRI results were validated by prostate-specific antigen (PSA) reduction after external beam radiotherapy in group A (126 patients, local recurrence size range 4–8 mm) and by transrectal ultrasound biopsy in group B (116 patients, local recurrence size range 9–15 mm).

Results

In group A combined T2-weighted and DCE-MRI (T2+DCE) shows 98 % sensitivity, 94 % specificity and 93 % accuracy in identifying local recurrence; combined T2-weighted and DWI with a b value of 3,000 s/mm² (T2+DW3) displays 97 % sensitivity, 95 % specificity and 92 % accuracy, while with a b value of 1,000 s/mm² (T2+DW1) affords 93 % sensitivity, 89 % specificity and 88 % accuracy. In group B T2+DCE shows 100 % sensitivity, 97 % specificity and 91 % accuracy in detecting local cancer recurrence; T2+DW3 displays 98 % sensitivity, 96 % specificity and 89 % accuracy; T2+DW1 has 94 % sensitivity, 92 % specificity and 86 % accuracy.

Conclusion

DCE-MRI is the most reliable technique in detecting local prostate cancer recurrence after RP, though DWI can be proposed as a reliable alternative.

Key Points

? Diffusion-weighted magnetic resonance imaging (DWI-MRI) is being increasingly used in oncology. ? PSA analysis does not distinguish prostate cancer recurrence from distant metastasis. ? DWI-MR can diagnose local prostate cancer recurrence after radical prostatectomy. ? DWI-MR is almost comparable to DCE-MRI in detecting local recurrence.     

Magnetic resonance imaging of the prostate with spectroscopic imaging using a surface coil. Initial clinical experience

PURPOSE: The purpose of this study was to evaluate the diagnostic ability of proton magnetic resonance spectroscopic imaging (MRSI) in the detection and localisation of prostate cancer, prospectively compared with histopathologic findings. MATERIALS AND METHODS: Magnetic resonance imaging (MRI) and MRSI were performed on 39 patients with prostate-specific antigen (PSA) levels greater than 4 ng/ml and suspicious findings at trans-rectal ultrasound (TRUS). All patients underwent a TRUS ten-core biopsy within 30 days according to a subdivision of the prostate into octants. All studies were interpreted by a dedicated radiologist who reported the areas of interest as normal, equivocal or suspicious on MRI. At MRSI, cancer was defined as possible if the ratio of choline plus creatine to citrate exceeded mean normal peripheral zone values by two standard deviations (SD) or as definite if that ratio exceeded the normal value by three SD. MRI and MRSI findings were spatially correlated with findings obtained from individual biopsy sites. RESULTS: MRI and MRSI alone had sensitivity, specificity, positive and negative predictive values and diagnostic accuracy in the detection of prostate cancer equal to 85%, 75%; 53%, 89%; 65%, 88%; 77%, 74%; and 69%, 79%, respectively. These values were 70%, 89%, 88%, 74% and 79% when MRI and MRSI were combined. Site-by-site analysis of MRI and MRSI findings and biopsy results yielded no significant correlation. CONCLUSIONS: The combination of MRSI and MRI provides a significantly higher specificity in the detection of tumours as compared with MRI alone and can be recommended as a problem-solving modality before biopsy in patients with high PSA levels and suspicious TRUS.     

基于PI-RADS V2研究多参数MRI诊断早期前列腺癌的价值

目的 基于前列腺影像报告和数据系统第2版(PI-RADS V2)探讨多参数MRI对早期前列腺癌(PCa)的诊断价值.方法 回顾性纳入27例行MRI检查[T2WI、扩散加权成像(DWI)、动态增强(DCE)]的早期PCa患者,2位放射科医师在不提供任何临床资料的情况下参照PI-RADS V2分析T2WI、DWI和DCE图像,按12分区法对前列腺各个分区出现癌的可能性进行评分.共组成4种方案.方案1:T2WI;方案2:T2WI+DWI;方案3:T2WI+DCE;方案4:T2WI+DWI+DCE.根据影像评分和病理结果对照,计算4种方案对早期PCa癌区和非癌区的平均PI-RADS V2评分并采用独立样本t检验比较,绘制受试者工作特征(ROC)曲线并采用Z检验比较曲线下面积(AUC)的差异,取约登指数最大值所对应的PI-RADS V2评分为界值,统计4种方案的敏感度、特异度及准确度.结果 27例早期PCa患者共纳入324区,119个癌区和205个非癌区,其中64个外周带癌区,55个移行区癌区.在方案1~4中,早期PCa癌区的PI-RADS V2评分分别为3.13±1.19、3.27±1.15、3.28±1.23、3.33±1.16,非癌区的PI-RADS V2评分分别为1.98±0.90、1.91±0.91、2.03±0.99、1.94±0.96,2组间PI-RADS V2评分在每种方案的差异均有统计学意义(P<0.05).各方案诊断早期PCa的AUC从大到小依次为:方案4(0.819)、方案2(0.810)、方案3(0.772)、方案1(0.765),各方案间的AUC差异均无统计学意义(P>0.05).方案1~4均以PI-RADS V2评分≥4分为临界值,诊断的敏感度分别为45.40%、56.30%、59.70%、61.34%;特异度分别为95.10%、96.10%、89.80%、96.60%;准确度分别为76.85%、81.48%、78.70%、83.65%.结论 多参数MRI有助于提高早期PCa的检出及诊断准确度,其中以T2WI+DWI+DCE的诊断价值最高.PI-RADS V2是一种评价早期PCa较好的半定量方法.     

The value of endorectal MR imaging to predict positive biopsies in clinically intermediate-risk prostate cancer patients

The aim of this study was to assess the effectiveness of endorectal MR imaging in predicting the positive biopsy results in patients with clinically intermediate risk for prostate cancer. We performed a prospective endorectal MR imaging study with 81 patients at intermediate risk to detect prostate cancer between January 1997 and December 1998. Intermediate risk was defined as: prostatic specific antigen (PSA) levels between 4 and 10 ng/ml or PSA levels in the range of 10–20 ng/ml but negative digital rectal examination (DRE) or PSA levels progressively higher (0.75 ng/ml year^–1). A transrectal sextant biopsy was performed after the endorectal MR exam, and also of the area of suspicion detected by MR imaging. The accuracies were measured, both singly for MR imaging and combined for PSA level and DRE, by calculating the area index of the receiver operating characteristics (ROC) curve. Cancer was detected in 23 patients (28 %). Overall sensitivity and specificity of endorectal MRI was 70 and 76 %, respectively. Accuracy was 71 % estimated from the area under the ROC curve for the total patient group and 84 % for the group of patients with PSA level between 10–20 ng/ml. Positive biopsy rate (PBR) was 63 % for the group with PSA 10–20 ng/ml and a positive MR imaging, and 15 % with a negative MR exam. The PBR was 43 % for the group with PSA 4–10 ng/ml and a positive MR study, and 13 % with a negative MR imaging examination. We would have avoided 63 % of negative biopsies, while missing 30 % of cancers for the total group of patients. Endorectal MR imaging was not a sufficient predictor of positive biopsies for patients clinically at intermediate risk for prostate cancer. Although we should not avoid performing systematic biopsies in patients with endorectal MR imaging negative results, as it will miss a significant number of cancers, selected patients with a PSA levels between 10–20 ng/ml or clinical-biopsy disagreement might benefit from endorectal MR imaging. Received: 8 February 2000/Revised: 7 July 2000/Accepted: 10 July 2000     

大范围扩散加权成像与骨扫描对照评价前列腺癌骨转移的前瞻性研究

目的 评价大范围(从头顶到小腿)MR DWI在前列腺痈骨转移瘤检测中的应用.方法 搜集接受前列腺MR检查的166例连续患者,所有患者均行前列腺局部扫描及大范围DWI.其中49例在1个月内接受骨扫描检查和大范围DWI并行双盲法诊断.以常规T1WI和压脂T2WI为标准,确定骨转移瘤的存在及其位置.49例均为MRI和核素检查后获得前列腺的穿刺病理结果.大范围DWI与骨扫描对骨转移瘤诊断的敏感度、特异度、受试者操作特征曲线(ROC曲线)下面积应用McNemar检验进行比较.转移瘤患者中有5例有>10处/例的全身多发骨转移,在以病灶为单位研究时不纳入计算.结果 49例中10例有骨转移瘤,而DWI和核素骨扫描分别诊断15和17例有骨转移瘤,大范围DWI和核素骨扫描诊断骨转移瘤的敏感度均为100%(10/10),特异性分别为87.2%(34/39)和82.1%(32/39),ROC曲线下面积分别为0.936和0.910.44例患者中2种技术共显示68处异常信号和(或)放射浓聚灶,有20处被证实为骨转移瘤,而DWI显示其中23处为骨转移瘤,核素骨扫描显示其中34处为骨转移瘤.以病灶为单位(68处)计算大范围DWI和核素骨扫描诊断骨转移瘤灶的敏感度均为90.0%(18/20),特异度分别为89.6%(43/48)和66.7%(32/48),ROC曲线下面积分别为0.898和0.783,大范围DWI的特异度高于骨扫描(P<0.01),ROC曲线下面积也高于核素骨扫描(P<0.05).结论 大范围DWI可用于前列腺癌骨转移瘤的检查,特异度和准确度高于骨扫描.     

超高b值弥散加权联合T2加权序列诊断外周带前列腺癌的价值

目的 探讨超高b值弥散加权成像（DWI）联合T2加权成像（T2WI）诊断外周带前列腺癌（PCa）的临床应用价值。 方法 选取2018年12月1日至2019年10月1日在佛山市第一人民医院行超声引导下前列腺靶点穿刺、临床病理学确诊并于穿刺前后1个月内行前列腺MRI检查的PCa患者41例，年龄49~89岁，中位年龄69岁。所有患者均行3.0T超高b值（分别为2000、3000 s/mm2）的DWI及T2WI脂肪抑制序列MRI成像。以前列腺靶点穿刺病理学结果为“金标准”，分别计算T2WI、DWI（b=2000 s/mm2）、DWI（b=3000 s/mm2）、T2WI+DWI（b=2000 s/mm2）、T2WI+DWI（b=3000 s/mm2）对PCa的诊断灵敏度、特异度和准确率。采用受试者工作特征（ROC）曲线分析计算各方法诊断PCa的曲线下面积。 结果 41例患者中，PCa患者26例（通过临床结合穿刺点位置确诊为外周带PCa），良性前列腺增生患者15例。T2WI、DWI（b=2000 s/mm2）、DWI（b=3000 s/mm2）、T2WI+DWI（b=2000 s/mm2）、T2WI+DWI（b=3000 s/mm2）诊断PCa的灵敏度分别为0.962（25/26）、0.962（25/26）、0.962（25/26）、0.923（24/26）、0.923（24/26），特异度分别为0.400（6/15）、0.667（10/15）、0.876（13/15）、0.800（12/15）、1.000（15/15），准确率分别为0.756（31/41）、0.854（35/41）、0.926（38/41）、0.878（36/41）、0.951（39/41），ROC曲线下面积分别为0.681、0.814、0.914、0.872、0.972（P=0.056、0.001、＜0.001、＜0.001、＜0.001）。 结论 T2WI+DWI（b=3000 s/mm2）序列图像诊断PCa具有较高的准确率，有望成为一种可靠的诊断前列腺疾病的无创性检查方法。     

MR 动态增强联合扩散加权成像对壶腹区良恶性病变的鉴别

目的：研究M R动态增强联合扩散加权成像（DWI）在鉴别壶腹区良恶性病变的价值。方法回顾性分析43例胆总管下段狭窄患者的M R动态增强及DWI的数据。其中包括32例恶性病变和11例慢性炎症。1位影像医生对壶腹周围良恶性病变的M R动态增强信号强度及DWI信号进行分析,另外2位影像医生对壶腹周围病变的M R动态增强影像以及M R动态增强联合DWI影像进行评估。应用 Logistic回归分析比较灵敏度及特异性。结果壶腹周围良恶性病变MR动态增强表现差异无统计学意义;DWI影像中,壶腹周围癌比炎症更多地表现为高信号,表观扩散系数（ADC）图表现为低信号（P＜0．001）。2位读片者在结合DWI影像后对恶性壶腹周围病变的诊断灵敏度均有提高,分别从84．4％提高到96．9％和从87．7％提高到96．6％。结论 M R动态增强联合DWI可提高鉴别壶腹周围区良恶性狭窄的诊断准确率。     

Diagnostic accuracy of ultra-high-b-value 3.0-T diffusion-weighted MR imaging for detection of prostate cancer

PurposeTo investigate the diagnostic accuracy of 3.0-T diffusion-weighted imaging (DWI) for detection of prostate cancer by using different b-values.MethodsSeventy-three patients underwent magnetic resonance imaging (MRI) at 3.0 T. Three MRI sets were reviewed by two radiologists: MRI and DWI (b=500s/mm²) (protocol A), MRI and DWI (b=1000s/mm²) (protocol B), and MRI and DWI (b=2000s/mm²) (protocol C). Areas under the receiver operating characteristic curve (AUCs) were calculated.ResultsThe mean of the AUCs in protocol C was larger than those in protocol A and in protocol B (P<.05).ConclusionDWI (b=2000s/mm²) at 3.0 T can improve the diagnostic accuracy for detection of prostate cancer.     

双参数MRI纹理分析鉴别诊断移行区前列腺癌及增生结节的价值

目的探讨双参数MRI纹理分析法在移行区前列腺癌及增生结节鉴别诊断中的应用价值。方法回顾性分析经病理证实的前列腺癌52例,增生结节39例。使用MRIcroN软件勾画病灶的范围,Matlab R2014b软件计算各纹理参数,用Fisher法选择独立纹理特征(包括方差,熵,偏度和峰度)及平均ADC值。使用两独立样本t检验评估各纹理参数及平均ADC值是否具有统计学差异。绘制受试者工作特征曲线并计算曲线下面积、敏感度和特异度。结果T 2WI前列腺癌组的方差低于增生组,熵高于增生组。ADC图前列腺癌组的方差和平均ADC值低于增生组,偏度、峰度、熵高于增生组。T 2WI熵联合ADC图熵的诊断价值最高(AUC=0.880),敏感度和特异度分别为73.7%,90.9%。结论T 2WI联合ADC图双参数纹理分析可准确区分前列腺癌与低信号增生结节,为两者的鉴别诊断提供客观、量化的依据。     

联合应用MR波谱分析与扩散加权成像定量指标行前列腺癌定量诊断

目的 以前列腺六分区为基础,量化分析并验证MRS与DWI两种功能成像的定量指标在联合诊断前列腺癌时的权重大小.方法 搜集2006年2月至2007年7月间前列腺MR检查数据库中患者资料,并以接受前列腺MR检查的不同时间段,将入选前列腺检查患者分为2组,分别用于定量分析和验证结果,第1组为从2006年2月至12月期间、第2组为从2007年1月至7月期间的患者.每例患者在行常规MRI后,均进行MRS和DWI检查,测量MRS可用体素的(胆碱+肌酸)/枸橼酸盐(CC/C)值和分区内最小ADC值(ADC_(mini)).以CC/C≥0.911作为阳性体素标准,计算前列腺MRS六分区内阳性体素比(PVR).采用聚类分析中的线性判别,计算第1组分区内PVR和ADC_(mini)合用时各自所占的权重.将第2组分区内PVR和ADC_(mini)代入公式,采用ROC分析比较单独及联合诊断的诊断效能.结果 第1组和第2组均有40例患者,非前列腺癌加例,前列腺癌20例.由第1组病例得出的联合诊断线性判别公式为DWI和MRS联合诊断的非标准化线性判别值(D)=3.264×ADC_(mini)-0.205×PVR-4.407,分区内PVR和ADC_(mini)的曲线下面积(Az)分别为0.769和0.910,联合诊断的Az为0.909.第2组病例分区内PVR和ADC_(mini)的Az分别为0.838和0.912,联合诊断的Az为0.915.2组的联合诊断效能与单独使用DWI的诊断效能差异均无统计学意义(X~2值分别为0.32和1.50,P值均＞0.05).结论 DWI对前列腺癌的诊断效能高于MRS,联用2种功能参数不能明显提高总体的诊断效能.     

Evaluation of T2-weighted and dynamic contrast-enhanced MRI in localizing prostate cancer before repeat biopsy

We assessed the accuracy of T2-weighted (T2w) and dynamic contrast-enhanced (DCE) 1.5-T magnetic resonance imaging (MRI) in localizing prostate cancer before transrectal ultrasound-guided repeat biopsy. Ninety-three patients with abnormal PSA level and negative prostate biopsy underwent T2w and DCE prostate MRI using pelvic coil before repeat biopsy. T2w and DCE images were interpreted using visual criteria only. MR results were correlated with repeat biopsy findings in ten prostate sectors. Repeat biopsy found prostate cancer in 23 patients (24.7%) and 44 sectors (6.6%). At per patient analysis, the sensitivity, specificity, positive and negative predictive values were 47.8%, 44.3%, 20.4% and 79.5% for T2w imaging and 82.6%, 20%, 24.4% and 93.3% for DCE imaging. When all suspicious areas (on T2w or DCE imaging) were taken into account, a sensitivity of 82.6% and a negative predictive value of 100% could be achieved. At per sector analysis, DCE imaging was significantly less specific (83.5% vs. 89.7%, p < 0.002) than T2w imaging; it was more sensitive (52.4% vs. 32.1%), but the difference was hardly significant (p = 0.09). T2w and DCE MRI using pelvic coil and visual diagnostic criteria can guide prostate repeat biopsy, with a good sensitivity and NPV.     

Combined diffusion-weighted and dynamic contrast-enhanced MRI for prostate cancer diagnosis--correlation with biopsy and histopathology

PURPOSE: To determine whether the combination of diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) MRI provides higher diagnostic sensitivity for prostate cancer than each technique alone. MATERIALS AND METHODS: Fourteen patients with a clinical suspicion of prostate cancer underwent endorectal MRI on a 1.5T scanner prior to transrectal ultrasound (TRUS)-guided biopsies. The average values of the apparent diffusion coefficient (ADC, calculated from b-values of 0 and 600), K(trans), v(e), maximum gadolinium (Gd) concentration, onset time, mean gradient, and maximum enhancement were determined. Correlation with histology was based on biopsy (six patients) and prostatectomy specimen (eight patients) results. The Tukey-Kramer test was used for statistical analysis. RESULTS: The average values of all MRI parameters, except v(e) and maximum Gd concentration, showed significant differences between tumor and normal prostate. The sensitivity and specificity values were respectively 54% (35-72%) and 100% (95-100%) for the ADC data, and 59% (39-77%) and 74% (63-83%) for the DCE data. When both ADC and DCE results were combined, the sensitivity increased to 87% (68-95%) and specificity decreased to 74% (62-83%). CONCLUSION: All but two DW- and DCE-MRI parameters showed significant differences between tumor and normal prostate. Combining both techniques provides better sensitivity, with a small decrease in specificity.     

Value of diffusion-weighted imaging for the prediction of prostate cancer location at 3T using a phased-array coil: preliminary results

OBJECTIVES: To retrospectively evaluate the imaging quality of diffusion-weighted imaging (DWI), compare the apparent diffusion coefficient (ADC) values for malignant and benign tissues in the peripheral zone (PZ) and transition zone (TZ), and evaluate whether T2-weighted imaging (T2WI) with DWI could improve the prediction of prostate cancer location when compared with T2WI at 3T using a phased-array coil. MATERIALS AND METHODS: Thirty-seven patients underwent T2WI and DWI before radical prostatectomy. The DWI technique with b = 0 and b = 1000 s/mm2 was used. ADC values were measured in benign and malignant tissues in the PZ or TZ. The prediction of prostate cancer location was evaluated in the PZ and TZ using T2WI and T2WI with DWI, respectively. Two readers in consensus recorded the presence of prostate cancer at magnetic resonance imaging and rated the imaging quality of DWI. RESULTS: For the prediction of 68 prostate tumors, the overall sensitivity and positive predictive value of T2WI with DWI were 84% and 86%, whereas those of T2WI were 66% and 63%, respectively (P < 0.05). The mean ADC values of malignant and benign tissues in the PZ and TZ were 1.30 +/- 0.26 and 1.96 +/- 0.20, and 1.35 +/- 0.24 and 1.75 +/- 0.23 x 10(-3)mm2/s, respectively (P < 0.01). The overall imaging quality was satisfactory or better in 97% of patients. CONCLUSION: DWI is a feasible technique that can be used for the differentiation of malignant and benign tissues in the PZ and TZ. Additionally, T2WI with DWI is superior to T2WI alone for the prediction of prostate cancer location.     

Evaluation of the potential of diffusion-weighted imaging in prostate cancer detection

BACKGROUND: Conventional T2-weighted (T2W) imaging alone has a poor sensitivity for prostate cancer detection. PURPOSE: To evaluate combined T2W and diffusion-weighted magnetic resonance imaging (DW-MRI) versus T2W MRI alone for identifying tumor in patients with prostate cancer. MATERIAL AND METHODS: Fifty-four consecutive patients with prostate cancer (46 stage 1 and 2, 8 stage 3) and sextant biopsies within the previous 3 months were studied. Endorectal MR images were analyzed by two radiologists (1 experienced, 1 trainee) blinded to patient information and histopathology. T2W images were scored first, followed by combined T2W and isotropic apparent diffusion coefficient (ADC) maps calculated from DW-MRI (b = 0, 300, 500, and 800 s/mm(2)). Gland apex, middle, and base for each side were scored negative, indeterminate, or positive for tumor. Imaging data for each sextant were compared with histology. Sensitivity, specificity, and interobserver agreement were calculated. RESULTS: Sensitivity and specificity for tumor identification significantly improved from 50% and 79.6% (T2W alone, experienced observer) to 73.2% and 80.8% (P<0.001), respectively. For the trainee observer, there was no improvement (44.3% and 72% T2W alone vs. 45.1% and 69.2% T2W plus ADC maps). Interobserver agreement was moderate for T2W imaging alone (kappa 0.51) and fair for T2W plus ADC maps (kappa 0.33). CONCLUSION: In an experienced observer, DW-MRI together with T2W imaging can significantly improve tumor identification in prostate cancer.     

MR spectroscopic imaging and diffusion-weighted imaging of prostate cancer with Gleason scores

Purpose:

To investigate functional changes in prostate cancer patients with three pathologically proven different Gleason scores (GS) (3+3, 3+4, and 4+3) using magnetic resonance spectroscopic imaging (MRSI) and diffusion‐weighted imaging (DWI).

Materials and Methods:

In this study MRSI and DWI data were acquired in 41 prostate cancer patients using a 1.5T MRI scanner with a body matrix combined with an endorectal coil. The metabolite ratios of (Cho+Cr)/Cit were calculated from the peak integrals of total choline (Cho), creatine (Cr), and citrate (Cit) in MRSI. Apparent diffusion coefficient (ADC) values were derived from DWI for three groups of Gleason scores. The sensitivity and specificity of MRSI and DWI in patients were calculated using receiver operating characteristic curve (ROC) analysis.

Results:

The mean and standard deviation of (Cho+Cr)/Cit ratios of GS 3+3, GS 3+4, and GS 4+3 were: 0.44 ± 0.02, 0.56 ± 0.06, and 0.88 ± 0.11, respectively. For the DWI, the mean and standard deviation of ADC values in GS 3+3, GS 3+4, and GS 4+3 were: 1.13 ± 0.11, 0.97 ± 0.10, and 0.83 ± 0.08 mm²/sec, respectively. Statistical significances were observed between the GS and metabolite ratio as well as ADC values and GS.

Conclusion:

Combined MRSI and DWI helps identify the presence and the proportion of aggressive cancer (ie, Gleason grade 4) that might not be apparent on biopsy sampling. This information can guide subsequent rebiopsy management, especially for active surveillance programs. J. Magn. Reson. Imaging 2012;36:697–703. © 2012 Wiley Periodicals, Inc.     

The value of diffusion-weighted imaging in combination with T2-weighted imaging for rectal cancer detection

OBJECTIVE: To evaluate the clinical value of diffusion-weighted imaging (DWI) in combination with T(2)-weighted imaging (T(2)WI) for the detection of rectal cancer as compared with T(2)WI alone. MATERIALS AND METHODS: Forty-five patients with rectal cancer and 20 without rectal cancer underwent DWI with parallel imaging and T(2)WI on a 1.5 T scanner. Images were independently reviewed by two readers blinded to the results to determine the detectability of rectal cancer. The detectability of T(2)W imaging without and with DW imaging was assessed by means of receiver operating characteristic analysis. The interobserver agreement between the two readers was calculated with kappa statistics. RESULTS: The ROC analysis showed that each of two readers achieved more accurate results with T(2)W imaging combined with DW imaging than with T(2)W imaging alone significantly. The A(z) values for the two readers for each T(2)WI and T(2)WI combined with DWI were 0.918 versus 0.991 (p=0.0494), 0.934 versus 0.997 (p=0.0475), respectively. The values of kappa were 0.934 for T(2)WI and 0.948 for T(2)WI combined with DWI between the two readers. CONCLUSION: The addition of DW imaging to conventional T(2)W imaging provides better detection of rectal cancer.