18F-脱氧葡萄糖正电子发射计算机断层显像CT检查在前列腺癌诊断和分期中的应用价值

目的 评价18F-脱氧葡萄糖(18F-FDG)正电子发射计算机断层显像CT检查(PET/CT)在前列腺癌诊断和分期中的应用价值.方法 经手术或穿刺活检病理证实为前列腺癌患者40例,年龄52 ～ 78岁,平均67岁.其中T24例,T316例,T420例.行18F-FDG PET/CT及99Tcm-MDPECT骨显像检查,统计PET/CT显像对前列腺癌原发灶、淋巴结转移及骨转移诊断的敏感性,对比分析PET/CT显像及99Tcm-MDPECT骨显像对骨转移的诊断效果.结果 40例患者中,18F-FDG PET/CT检查显示前列腺局部结节状放射性浓聚17例,对原发灶诊断敏感性为43％.17例淋巴结转移患者中CT检查发现8例,18F-FDG PET/CT检查发现15例,诊断敏感性为88％,其中5例患者因PET/CT检查改变了临床分期以及治疗方案.18F-FDG PET/CT对骨转移诊断的敏感性与99Tcm-MDP骨显像相近,但特异性(95％)和准确率(96％)均明显高于99Tcm-MDP骨显像,其中6例患者因PET/CT检查改变了临床分期,2例改变了治疗方案.结论 18F-FDG PET/CT对前列腺癌淋巴结转移和骨转移有较高诊断价值,对前列腺的分期具有特殊优势,可为临床医生制定治疗方案提供可靠依据.     

PET/CT显像中SUVmax对骨转移瘤与骨髓瘤鉴别诊断的价值

目的 回顾性分析未知原发灶的多发性骨破坏患者PET/CT显像中骨髓瘤与骨转移瘤病变SUVmax的特征,为临床鉴别诊断提供依据.方法 CT或MRI发现的多发骨破坏患者119例,其中71例PET/CT检查后行病理检查,男40例,女31例;年龄37～87岁,平均61-3岁.病理确诊骨髓瘤21例,骨转移瘤41例.测量骨髓瘤和骨转移瘤每个骨病变的SUVmax并进行比较,采用ROC曲线获得鉴别诊断的分界点.采用单因素方差分析比较不同形态学特征(溶骨性和成骨性)骨转移瘤与骨髓瘤SUVmax的差异.结果 PET/CT在骨髓瘤病例中共检出315个病灶,在骨转移瘤病例中共检出684个病灶.骨髓瘤病灶SUVmax(3.42±1.96)值明显低于转移瘤病灶(7.03±4.15).SUVmax值为4.45时,鉴别骨髓瘤和骨转移瘤的敏感性和特异性分别为80.4%和72.4%.溶骨性骨转移瘤病灶SUVmax值(8.02±4.85)明显高于成骨性骨转移瘤(4.79±2.61)和骨髓瘤(3.37±1.92),而成骨性骨转移瘤与骨髓瘤病灶的SUVmax值差异无统计学意义(P>0.05).结论 PET/CT对未知原发灶的多发性骨破坏患者骨髓瘤与骨转移瘤的鉴别诊断具有潜在的价值,多发性骨破坏病灶SUVmax值较低和溶骨性破坏可提示骨髓瘤.     

18F-FDG PET/CT与多层螺旋CT在进展期胃癌术前TNM分期的对比研究

目的 应用18F-FDG PET/CT(PET/CT)与多层螺旋CT对进展期胃癌术前TNM分期进行对比研究,以期更客观地评估术前分期,指导治疗.方法 对术前行PET/CT检查的39例及MSCT检查的40例进展期胃癌,分别进行术前TNM分期,将检测结果与术中所见及病理进行对照.结果 PET/CT对原发灶、区域淋巴结、N3转移淋巴结的准确率分别为92.3%、66.7%、100.0%;而MSCT诊断的准确率分别为82.0%、50.0%、62.5%.结论 (1)PET/CT和多层螺旋CT对原发灶、区域淋巴结转移的准确率都较高,差异无统计学意义,由于多层螺旋CT临床应用广泛且费用远低于PET/CT,是首选的检测手段;(2)PET/CT对N3转移淋巴结、远处转移灶检测的准确率明显高于多层螺旋CT,为临床提供更为全面客观的术前分期,指导治疗;(3)由于PET/CT也存在一定假阴性,结合腹腔镜检可减少或避免不必要的剖腹术.     

18F-FDG PET/CT显像在肾癌中的临床应用价值

目的:评价18F-脱氧葡萄糖(18F-fluorodeoxyglucose,18F-FDG)正电子发射计算机断层扫描(PET)/CT显像对肾癌诊断和治疗方案选择的临床应用价值.方法:回顾性分析56例临床诊断为肾癌患者的全身18F-FDG PET/CT和CT平扫加增强扫描的影像学资料.比较两者对肾癌的诊断价值.结果:56例患者中,经手术病理检查实为肾癌者47例.其余9例因18F-FDG PET/CT显像发现有转移病灶者放弃手术.18F-FDG;PET/CT 榆古敏感度为80.4%;CT平扫加增强扫描的敏感度为92.9%.9例转移病例中,3例为腹膜后淋巴结转移,3例两肺多发转移,2例骨转移并肝转移,1例伴有下腔静脉和肾静脉癌栓形成,而CT平扫加增强扫描仅发现1例肾静脉和下腔静脉痛栓形成.结论:18F-FDG PET/CT显像对诊断原发性肾癌的敏感性不如CT,但对淋巴结转移及远处转移的诊断优于CT,对肾癌的分期、治疗方案的选择及预后的判断有重要意义.     

核磁共振、正电子发射扫描在感染性脊柱炎诊断中的应用价值研究

目的 探讨核磁共振(MRI)、18氟-氟代脱氧葡萄糖(18F-FDG)正电子发射断层扫描成像/计算机断层扫描成像(PET/CT)在感染性脊柱炎诊断中的应用价值.方法 回顾2001年1月～2019年12月期间在河北北方学院附属第一医院进行感染性脊柱炎筛查的100例患者的临床资料.所有受试者经组织病理学和细菌学检查,有明确的诊断结果,并接受MRI及18 F-FDG PET/CT检查.分析MRI、18 F-FDG PET/CT检查在感染性脊柱炎诊断中的意义.结果 MRI、18 F-FDG PET/CT检查均为感染性脊柱炎诊断结果的独立影响因素.ROC曲线分析结果显示,MRI、18 F-FDG PET/CT及联合预测因子在诊断感染性脊柱炎中的曲线下面积(AUC)分别为0.896、0.958、0.973,均有统计学意义(P<0.01).MRI与18F-FDG PET/CT联合检测在感染性脊柱炎诊断中的诊断效能最理想,准确度、敏感度、特异度分别为99.00％、100.00％、97.50％.结论 将MRI与18 F-FDG PET/CT联合检测感染性脊柱炎,能够明显提升诊断的准确率.     

WBDWI评价肿瘤转移灶的价值探讨

目的 探讨WBDWI评价肿瘤转移灶的临床价值.方法回顾性分析本院近年来诊断的42例转移瘤病例及10例健康体检者WBDWI检查的临床资料,将WBDWI检查结果与其CT、MRI或PET等检查的综合确诊结果做对比分析,统计不同部位WBDWI检查的病灶检出情况,以评价WBDWI应用于肿瘤转移灶检出的临床价值.结果 10例志愿者WBDWI与PET检查结果相符,均为阴性.42例转移瘤患者确诊病灶122处,WBDWI共发现108处,真阳性结果106处,阳性显示率86.9%.假阴性结果4处病灶,假阴性率3.3%.纵膈、盆腔的淋巴结转移及成骨转移不易发现,其他检查部位的WBDWI结果与确诊结果相符.结论 WBDWI在转移瘤检出方面准确性高,有利于评估肿瘤的原发灶及筛查其它脏器的转移灶,且安全、经济,是一种有良好发展空间的全身检查手段.     

脊椎结核的18F-FDG PET/CT表现及诊断价值

目的探讨18F-FDG PET/CT对脊椎结核的诊断价值。方法回顾我院10例脊椎结核的PET/CT表现,SUV>2.5定为放射性摄取增高,并对比MRI图像,分析其对脊椎结核的诊断符合率。随访时间为12～24个月。结果有完整资料的10例脊椎结核患者,MRI诊断脊柱结核6例(60%),其余均诊断为转移瘤。18F-FDG PET/CT诊断脊椎结核10例,共计16个椎体,其中4例为单一椎体受累,6例患者表现为2个连续椎体同时受累,以胸腰段椎体为主。PET/CT和MRl检出病灶率相同,均为100%,定性诊断正确率分别为100%和60%,二者定性诊断比较有统计学意义。结论 PET/CT在诊断脊椎骨结核方面优于MRI,能为临床的诊治提供更准确的影像信息。     

18F-FDG PET/CT在胆道系统恶性肿瘤中的应用

目的探讨~(18)F-FDG PET/CT诊断胆道系统恶性肿瘤的价值。方法回顾性分析34例临床疑似胆道恶性肿瘤患者的PET/CT影像资料,均获得术后病理结果,其中12例经手术切除淋巴结或淋巴结穿刺活检对18枚淋巴结获得病理诊断;与病理结果对照,计算PET/CT对胆道恶性病变原发灶、淋巴结转移的灵敏度、特异度、阳性预测值、阴性预测值及准确率。结果 34例中,31例为恶性病变,3例为良性病变。PET/CT诊断胆道恶性肿瘤原发灶的灵敏度100%(31/31),特异度66.67%(2/3),阳性预测值96.88%(31/32),阴性预测值100%(2/2),准确率97.06%(33/34)。胆道恶性病变原发灶最大标准摄取值(SUV_(max))为8.42±4.27;3例胆道良性疾病SUV_(max)分别为12.90、2.00及1.90。共18枚淋巴结获得病理结果,包括转移性淋巴结13枚,良性增生5枚。PET/CT诊断淋巴结转移的灵敏度76.92%(10/13),特异度60.00%(3/5),阳性预测值83.33%(10/12),阴性预测值50.00%(3/6),准确率72.22%(13/18)。结论 PET/CT对胆道系统恶性肿瘤的诊断具有重要价值。     

18氟脱氧葡萄糖正电子扫描和计算机断层扫描应用于胃癌术前分期的研究

目的 研究18氟脱氧葡萄糖正电子扫描(18F-FDG PET)和计算机断层扫描(CT)融合显像(18F-FDG PET/CT)在胃癌术前分期中的作用.方法 2006年1月至2009年12月间经内镜活检与病理学检查确诊、并使用18F-FDG PET/CT作术前评估的胃癌患者67例.对比分析18F-FDG PET/CT的术前分期和手术病理学检查结果,探讨18F-FDG PET/CT在胃癌术前分期中的敏感度、特异性和准确度.结果 癌细胞转移到淋巴结50例,肝2例,网膜3例,肠系膜2例,肠壁2例,腹膜4例,肺1例,骨1例,子宫、附件2例.18F-FDG PET/CT对胃癌术前分期的敏感度、特异性和准确度分别是87%,96%和88%.18F-FDG PET/CT对不同TNM分期胃癌的敏感度、特异性和准确度并不相同,分别是Ⅰ期50%,100%,50%;Ⅱ期89%,87%,89%和Ⅲ期86%,97%,86%.但Ⅳ期胃癌的敏感度、特异性和准确度均为100%.结论 18F-FDG PET/CT不仅能检测肿瘤原发灶和周围淋巴结,且能全面了解病变全身的累及范围,对制定合理的治疗方案有重要的参考价值.特别是对不能根治的胃癌具有极高的诊断率,可避免不必要的手术探查.     

脊椎骨挫伤的18F-FDG PET/CT诊断价值

目的探讨18F-FDG PET/CT对脊椎骨挫伤的诊断价值。方法回顾我院18例脊椎骨挫伤的PET/CT表现,SUV>2.5定为放射性摄取增高,并对比MRI图像,分析其对脊椎骨挫伤的诊断符合率。随访时间为6～24个月。结果有完整资料的18例脊椎骨挫伤患者,X线平片及CT未能检出异常,MRI诊断骨挫伤6例(33.3%),其余均诊断为转移瘤。18F-FDG PET/CT诊断脊椎骨挫伤18例,共计20个椎体,其中16例为单一椎体,2例患者表现为2个椎体,以胸腰段椎体为主。PET/CT和MRl检出病灶率相同,均为100%,定性诊断正确率分别为100%和40%,二者定性诊断比较有统计学意义(X2=17.14,P<0.05)。结论 PET/CT在诊断脊椎骨挫伤方面优于MRI,能为临床的诊治提供更准确的影像信息。     

18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) is accurate for high-grade prostate cancer bone staging when compared to bone scintigraphy

IntroductionIn this study, we compared ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG)-positron emission tomography/computed tomography (PET/CT) and bone scintigraphy accuracies for the detection of bone metastases for primary staging in high-grade prostate cancer (PCa) patients to determine if ¹⁸F-FDG-PET/CT could be used alone as a staging modality.MethodsMen with localized high-grade PCa (n=256, Gleason 8–10, International Society of Urological Pathology [ISUP] grades 4 or 5) were imaged with bone scintigraphy and ¹⁸F-FDG-PET/CT. We compared, on a per-patient basis, the accuracy of the two imaging modalities, taking inter-modality agreement as the standard of truth (SOT).Results¹⁸F-FDG-PET/CT detected at least one bone metastasis in 33 patients compared to only 26 with bone scan. Of the seven false-negative bone scintigraphies, four (57.1%) were solitary metastases (monometastatic), three (42.9%) were oligometastatic (2–4 lesions), and none were plurimetastatic (>4 lesions). Compared to SOT, ¹⁸F-FDG-PET/CT showed higher sensitivity and accuracy than bone scintigraphy (100% vs. 78.8%, and 98.7% vs. 98.2%) for the detection of skeletal lesions.Conclusions¹⁸F-FDG-PET/CT appears similar or better than conventional bone scans to assess for bone metastases in patients newly diagnosed with high-grade PCa. Since intraprostatic FDG uptake is also a biomarker for failure of radical prostatectomy and that FDG-PET/CT has been shown to be accurate in detecting PCa lymph node metastasis, FDG-PET/CT has the potential to be used as the sole preoperative staging modality in high-grade PCa.     

11C-choline positron emission tomography in bladder cancer: Report of four cases

Little work has been done with positive emission tomography (PET) in bladder tumors because high urinary excretion of (18)F-FDG makes visualization of the bladder tumor difficult. (11)C-choline has recently been reported as a new tracer which lacks urinary radioactivity. We report the result of (11)C-choline PET in four patients with invasive bladder tumors. In one case, (11)C-choline PET could detect bladder tumor effectively without urinary activity and bone metastasis despite negative bone scintigraphy. On the other hand, an intense accumulation of the tracer in the bladder hampered the interpretation on PET scanning in three patients. The mechanisms of the (11)C-choline accumulation in the bladder were reported to be due to inflammatory and proliferative changes in the mucosa of the bladder from previous catheterization or other factors. Further study is necessary to prove the value of (11)C-choline PET for detecting primary bladder cancer and bone metastasis.     

18F-FDG PET/CT评价非霍奇金淋巴瘤骨髓浸润

目的探讨^18F-FDG PET／CT评价非霍奇金淋巴瘤（NHL）骨髓浸润的临床应用价值,并与骨髓活检（BMB）及流式细胞分析（FCM）进行比较。方法回顾性分析89例经病理证实且未经治疗的NHL患者^18F-FDG PET／CT资料,其中侵袭性NHL76例,惰性NHL13例。所有患者均在^18F-FDG PET／CT检查2周内接受BMB及FCM,对^18F-FDG PET／CT显示骨髓局灶性^18F—FDG摄取增高而BMB及FCM阴性患者,根据PET／CT所示骨髓异常部位再次行BMB确定骨髓是否受累。结果89例NHL患者中,根据BMB、FCM及PET／CT引导下再次BMB结果,共检出骨髓浸润26例,检出率为29．21％（26／89）,PET／CT检出率为21．35％（19／89）。PET／CT诊断骨髓浸润的灵敏度为73．08％（19／26）,特异度为96．83％（61／63）,准确率为89．89％（80／89）,阳性预测值为90．48％（19／21）,阴性预测值为89．71％（61／68）。BMB及FCM检出率均为19．10％（17／89）,PET／CT较BMB、FCM骨髓浸润检出率稍高,但差异无统计学意义（P〉0．05）。将PET／CT、FCM及BMB三种方法联合诊断骨髓浸润,其检出率高于其中任意一种方法（P〈0．05）。PET／CT对侵袭性NHL骨髓浸润的检出率22．37％（17／76）高于对惰性NHL骨髓浸润的检出率15．38％（2／13,P〈0．06）。结论^18F-FDG PET／CT在诊断NHL骨髓浸润中有较高的应用价值。对局灶性骨髓浸润患者,PET／CT有助于引导BMB部位,提高骨髓浸润的检出率。PET／CT未检出骨髓浸润的惰性NHL患者,应进一步行BMB及FCM检查。推荐PET／CT、FCM及BMB三种方法联合应用判断NHL骨髓浸润,从而更准确地进行分期、治疗及判断预后。     

PTE-CT对肝炎性肝硬化并肝细胞癌的诊断价值

目的 评价18F氟脱氧葡萄糖(18F-FDG)PET-CT诊断肝炎性肝硬化并肝细胞癌的价值.方法 分析肝硬化并肝细胞肝癌行18F-FDG PET-CT检查22例,共36个病灶.根据FDG的摄取将病灶分为2种类型,A型病变部位摄取高于周围正常组织;B型与周围组织相近,与手术后病理结果对比.结果 中分化肝细胞癌15个、低分化肝细胞癌8个病灶表现为A型,高分化肝细胞癌7个和肝脏再生性结节6个病灶为B型.结论 18F-FDG PET-CT对高分化肝细胞癌诊断效果差,对中低分化肝细胞癌诊断效果好.18F-FDG PET-CT对肝脏的多个占位性病灶中单个病灶的良恶性鉴别有重要价值.     

Dual-Time <Superscript>18</Superscript>F-FDG PET/CT Imaging in Initial Locoregional Staging of Breast Carcinoma: Comparison with Conventional Imaging and Pathological Prognostic Factors

The aims of this retrospective study were to consider the diagnostic role of dual-time ¹⁸F-fluorodeoxyglucose positron emission tomography and computed tomography (¹⁸F-FDG PET/CT) in detection of breast carcinoma and axillary lymph node (ALN) status and to evaluate the primary tumor ¹⁸F-FDG uptake pattern. Preoperative staging was performed by ¹⁸F-FDG PET/CT in 78 female patients with breast carcinoma. Conventional imaging results were evaluated by breast magnetic resonance imaging (MRI) of 79 lesions in 78 patients, bilateral mammography (MMG) of 40 lesions in 40 patients, and breast ultrasonography (USG) of 47 lesions in 46 patients. The primary tumor detection rate using ¹⁸F-FDG PET/CT was higher than those using MRI, USG, and MMG. The sensitivity and specificity of ¹⁸F-FDG PET/CT scans for detecting multifocality were higher than those of MRI. The specificity of ALN metastasis detection with MRI was higher than that with ¹⁸F-FDG PET/CT, but ¹⁸F-FDG PET/CT had higher sensitivity. Higher ¹⁸F-FDG uptake levels were detected in patients with ALN metastasis, histologic grade 3, estrogen–progesterone-negative receptor status, lymphatic invasion, and moderate to poor prognostic groups. There was no statistical difference for the retention index in categorical pathological parameters except for progesterone-negative status. In conclusion, ¹⁸F-FDG PET/CT scans may be a valuable imaging technique for evaluating primary tumor and axillary status in staging breast carcinoma and ¹⁸F-FDG uptake may be a prognostic factor that indicates aggressive tumor biology and poor prognosis. Dual-time imaging in breast carcinoma staging may not be used for predicting pathological criteria and the aggressiveness of primary lesions.     

Clinical use of fluorodeoxyglucose F 18 positron emission tomography for detection of renal cell carcinoma

PURPOSE: We evaluate the role of fluorodeoxyglucose F 18 positron emission tomography (PET) in patients with renal cell carcinoma (RCC) by retrospective review. To our knowledge this series is the largest reviewing the use of PET in patients with RCC. MATERIALS AND METHODS: A total of 66 patients who underwent 90 PET scans for suspected or known RCC were identified. Dictated reports of PET, chest computerized tomography (CT), abdominal/pelvic CT and bone scan were examined with confirmation of results by histopathology or followup of at least 1 year. The accuracies of PET and conventional imaging modalities were compared. RESULTS: PET exhibited a sensitivity of 60% and specificity of 100% for primary RCC tumors (abdominal CT demonstrated 91.7% sensitivity and 100% specificity). For retroperitoneal lymph node metastases and/or renal bed recurrence, PET was 75.0% sensitive and 100.0% specific (92.6% sensitivity and 98.1% specificity for abdominal CT). PET had a sensitivity of 75.0% and a specificity of 97.1% for metastases to the lung parenchyma compared to 91.1% and 73.1%, respectively, for chest CT. PET had a sensitivity of 77.3% and specificity of 100.0% for bone metastases, compared to 93.8% and 87.2% for combined CT and bone scan. In 39 scans (32 patients) PET failed to detect RCC lesions identified by conventional imaging. CONCLUSIONS: The role of fluorodeoxyglucose F 18 PET in the detection of RCC is limited by low sensitivity. With superior specificity PET may have a complementary role as a problem solving tool in cases that are equivocal on conventional imaging.     

Positron‐emission tomography/computed tomography (PET/CT) in the initial staging of primary rectal cancer

Objective The aim of this study was to assess the role of ¹⁸flourodeoxyglucose positron‐emission tomography/computed tomography (PET/CT) in the initial staging of primary rectal adenocarcinoma. Method A total of 20 patients with adenocarcinoma of the rectum were assessed with both PET/CT and conventional staging (CT chest/abdomen/pelvis, MRI rectum). Discordance with conventional imaging and incidental findings on PET were recorded and the patients presented to a colorectal cancer multidisciplinary team to assess management changes. Patients were followed up so that discordant or incidental findings could be verified by intra‐operative examination, imaging or histology where possible. Results Positron‐emission tomography/computed tomography correctly identified the primary tumour in all 20 patients. Comparing PET/CT with conventional staging modalities, there were 11 discordant or incidental findings in nine patients (45%). This resulted in a potential change in stage in 30% (four patients downstaged and two upstaged). PET/CT suggested additional neoplastic pathology in three patients and excluded the same in two patients. The incidental neoplastic findings were of minor clinical significance and one was eventually deemed false positive. While PET/CT resulted in potential management changes in five patients (25%), no changes in surgical management occurred. When tumours were grouped according to conventional stage, PET/CT resulted in fewer changes in stage in stage I (0%), compared with stages II to IV (43%) (P = 0.08). Conclusion Positron‐emission tomography/computed tomography provides additional information to conventional staging in primary rectal cancer. This information produced minor management changes in this study and did not effect surgical management. PET/CT may be most appropriately used selectively in more advanced stages and where indeterminate findings exist with conventional staging.     

Preoperative lymph-node staging of invasive urothelial bladder cancer with 18F-fluorodeoxyglucose positron emission tomography/computed axial tomography and magnetic resonance imaging: correlation with histopathology

OBJECTIVE: The treatment and prognosis of bladder cancer are based on the depth of primary tumour invasion and the presence of metastases. A highly accurate preoperative tumour, node, metastasis (TNM) staging is critical to proper patient management and treatment. This study retrospectively investigated the value of 1?F-fluorodeoxyglucose (FDG) positron emission tomography/computed axial tomography (1?F-FDG PET/CT) and magnetic resonance imaging (MRI) for preoperative N staging of bladder cancer. Material and methods. From June 2006 to January 2008, 48 consecutive patients diagnosed with bladder cancer were referred to preoperative staging including MRI and 1?F-FDG PET/CT. Eighteen out of 48 patients underwent radical cystoprostatectomy including removal of lymph nodes for histology, and were included in the study. Values of 1?F-FDG PET/CT and MRI for regional N staging were compared to histopathology findings, the gold standard. Results. 1?F-FDG PET/CT and MRI were performed in 18 patients. The specificities for detection of lymph-node metastases for MRI and 1?F-FDG PET/CT were 80% (n = 15) and 93.33% (n = 15), respectively. The negative predictive values were 80% (n = 15) and 87.5% (n = 16) for MRI and 1?F-FDG PET/CT, respectively. The differences in specificity and negative predictive values were not statistically significant. Conclusions. No significant statistical difference between 1?F-FDG PET/CT and MRI for preoperative N staging of urothelial bladder cancer was found in the study. However, the trend of the data indicates an advantage of 1?F-FDG PET/CT over MRI. Larger prospective studies are needed to elucidate the role of 1?F-FDG PET/CT in N staging of bladder cancer.