Vallini Valentina, Ortori Simona, Boraschi Piero, Manassero Francesca, Gabelloni Michela, Faggioni Lorenzo, Selli Cesare, Bartolozzi Carlo
Department of Diagnostic and Interventional Radiology, University of Pisa, Via Paradisa 2, 56124 Pisa, Italy.
Department of Urology, University of Pisa, Via Paradisa 2, 56124 Pisa, Italy.
Eur J Radiol Open. 2015 Dec 11;3:16-21. doi: 10.1016/j.ejro.2015.11.004. eCollection 2016.
To evaluate the usefulness of diffusion-weighted imaging (DWI) with a multiple b value SE-EPI sequence on a 3.0 T MR scanner for staging of pelvic lymph nodes in patients with prostate cancer candidate to radical prostatectomy and extended pelvic lymph node dissection (PLND).
Institutional review board approval was obtained and written informed consent was taken from all enrolled subjects. A series of 26 patients with pathologically proven prostate cancer (high or intermediate risk according to D'Amico risk groups) scheduled for radical prostatectomy and PLND underwent 3 T MRI before surgery. DWI was performed using an axial respiratory-triggered spin-echo echo-planar sequence with multiple b values (500, 800, 1000, 1500 s/mm(2)) in all diffusion directions. ADC values were calculated by means of dedicated software fitting the curve obtained from the corresponding ADC for each b value. Fitted ADC measurements were performed at the level of proximal and distal external iliac, internal iliac, and obturator nodal stations bilaterally. Lymph node appearance was also assessed in terms of short axis, long-to-short axis ratio, node contour and intranodal heterogeneity of signal intensity.
A total of 173 lymph nodes and 104 nodal stations were evaluated on DWI and pathologically analysed. Mean fitted ADC values were 0.79 ± 0.14 × 10(-3) mm(2)/s for metastatic lymph nodes and 1.13 ± 0.29 × 10(-3) mm(2)/s in non-metastatic ones (P < 0.0001). The cut-off for fitted ADC obtained by ROC curve analysis was 0.91 × 10(-3) mm(2)/s. A two-point-level score was assigned for each qualitative parameter, and the mean grading score was 6.09 ± 0.61 for metastastic lymph nodes and 5.42 ± 0.79 for non-metastatic ones, respectively (P = 0.001). Using a score threshold of 4 for morphological, structural, and dimensional MRI analysis and a cut--off value of 0.91 × 10(-3) mm(2)/s for fitted ADC measurements of pelvic lymph nodes, per--station sensitivity, specificity, PPV, NPV and diagnostic accuracy were 100%, 7.9%, 15.6%, 100% and 21.3%, and 84.6%, 89.5%, 57.9%, 97.1% and 88.8%, respectively.
3.0T DWI with a multiple b value SE-EPI sequence may help distinguish benign from malignant pelvic lymph nodes in patients with prostate cancer.
评估在3.0 T磁共振成像（MR）扫描仪上使用具有多个b值的自旋回波平面成像（SE-EPI）序列进行扩散加权成像（DWI），对拟行根治性前列腺切除术和扩大盆腔淋巴结清扫术（PLND）的前列腺癌患者盆腔淋巴结进行分期的有效性。
获得机构审查委员会批准，并取得所有入组受试者的书面知情同意书。26例经病理证实为前列腺癌（根据达米科风险分组为高风险或中风险）且计划行根治性前列腺切除术和PLND的患者在手术前行3 T磁共振成像检查。在所有扩散方向上使用具有多个b值（500、800、1000、1500 s/mm²）的轴向呼吸触发自旋回波回波平面序列进行DWI检查。通过专用软件拟合从每个b值对应的表观扩散系数（ADC）获得的曲线来计算ADC值。在双侧髂外、髂内和闭孔淋巴结站的近端和远端层面进行拟合ADC测量。还根据短轴、长短轴比、淋巴结轮廓和淋巴结内信号强度的异质性评估淋巴结表现。
共对173个淋巴结和104个淋巴结站进行了DWI评估和病理分析。转移淋巴结的平均拟合ADC值为0.79±0.14×10⁻³ mm²/s，非转移淋巴结为1.13±0.29×10⁻³ mm²/s（P<0.0001）。通过ROC曲线分析获得的拟合ADC的截断值为0.91×10⁻³ mm²/s。为每个定性参数指定一个两点分级评分，转移淋巴结的平均分级评分为6.09±0.61，非转移淋巴结为5.42±0.79（P = 0.001）。对于盆腔淋巴结的形态、结构和尺寸MRI分析，使用评分阈值4，对于拟合ADC测量，使用截断值0.91×10⁻³ mm²/s，每个淋巴结站的敏感性、特异性、阳性预测值、阴性预测值和诊断准确性分别为100%、7.9%、15.6%、100%和21.3%，以及84.6%、89.5%、57.9%、97.1%和88.8%。
3.0 T DWI结合多个b值的SE-EPI序列可能有助于区分前列腺癌患者盆腔淋巴结的良恶性。
