Comparison of PET-CT and magnetic resonance diffusion weighted imaging with body suppression (DWIBS) for initial staging of malignant lymphomas

Objective

To evaluate the clinical impact of diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) in staging of malignant lymphoma.

Methods

Twenty-three patients with proven malignant lymphomas were prospectively enrolled. DWIBS (b = 0, 1000 s/mm²) examinations and PET-CT were performed respectively on an Intera 1.5 T unit and a Gyroscan PET-CT scan (Philips Medical system, Best, the Netherland). The criteria for positive node involvement were a size over 10 mm or an apparent diffusion coefficient (ADC) value under 0.75 10⁻³ mm²/s for nodes under 10 mm. For extranodal analysis, a high or heterogeneous signal on DWIBS was considered as positive. In cases of discordance, the reference standard for each region or organ was established at 6 months after the diagnosis according to all available clinical, biological information, as well as histological evidence or follow-up to prove or disprove the presence of disease.

Results

DWIBS and PET-CT results were congruent in 333 node regions on the 345 areas analyzed, with excellent agreement (κ = 0.97, P < 0.0001). From 433 organs analyzed (one patient had splenectomy) extranodal disease was detected in 22 organs on DWIBS. The two imaging techniques agreed on 430 organs (κ = 0.99, P < 0.0001). Finally, Ann Arbor stages based on DWIBS and those of PET/CT were in agreement for 23 patients.

Conclusions

For malignant lymphoma in a pre-therapeutic context, agreement between diffusion-weighted whole-body imaging and PET/CT is high for Ann Arbor staging.     

Whole-body diffusion-weighted magnetic resonance imaging

Diffusion-weighted magnetic resonance imaging (DWI) provides information on the diffusivity of water molecules in the human body. Technological advances and the development of the concept of diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) have opened the path for routine clinical whole-body DWI. Whole-body DWI allows detection and characterization of both oncological and non-oncological lesions throughout the entire body. This article reviews the basic principles of DWI and the development of whole-body DWI, illustrates its potential clinical applications, and discusses its limitations and challenges.     

DWIBS技术在子宫卵巢恶性肿瘤方面应用价值

目的探讨磁共振背景抑制弥散成像（diffusion weighted imaging with background suppression,DWIBS）技术在子宫卵巢恶性肿瘤方面的应用价值。方法对临床确诊的14例子宫内膜癌,32例宫颈癌,5例卵巢癌,1例阴道癌患者进行MRI常规及DWIBS检查,经3D容积与MIP重建,进行影像与临床对比分析。结果根据FIGO外科分期,Ⅰ期25例,Ⅱ期15例,Ⅲ期10例,Ⅳ期7例,术后复发转移4例,术后正常1例。48例患者原发和转移病灶在DWIBS图像上表现为高亮或高信号,1例子宫内膜癌Ⅰa期,2例宫颈癌Ⅰa期及1例宫颈癌术后患者病灶在DWIBS图像上显示为正常。结论除子宫内膜癌及宫颈癌Ⅰa期病变外,结合MRI平扫与DWIBS图像能清楚显示病灶及其侵犯和转移情况,对子宫与卵巢病变的术前分期及疗效评估有较大的价值。     

A Rare Case of Pulmonary Tumor Thrombotic Microangiopathy Associated with Micropapillary Urothelial Carcinoma of the Urinary Bladder: An Autopsy Case

A 70-year-old woman was hospitalized with dyspnea. A transthoracic echocardiogram indicated an elevated systolic pulmonary artery pressure, and the cytology specimens obtained using a pulmonary artery catheter confirmed adenocarcinoma metastasis. Diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) detected high-signal-intensity lesions in the urinary bladder. The patient died of respiratory failure and a postmortem examination was performed. Tumor cells in the bladder were immunohistochemically positive for GATA3, indicating micropapillary urothelial carcinoma, which is a rare variant of urothelial carcinoma and considered an adenocarcinoma subtype. This case is the first autopsy case of pulmonary tumor thrombotic microangiopathy (PTTM) associated with micropapillary urothelial carcinoma of the urinary bladder.     

DWIBS: Can it replace DCE-MRI in detection and characterization of suspicious breast lesions?

Objectives

Unenhanced MR imaging of the breast have recently been introduced. These include STIR, T2-weighted TSE and DWIBS sequences. These sequences could characterize breast lesions, although not yet able to avoid histological characterization.

A comparative study of whole body DWIBS MRI versus bone scan for evaluating skeletal metastases

Background

Skeletal metastases in oncology patients are identified by Bone scan and/Positron Emission Tomography (PET) scan. But developing countries in the world still lack adequate numbers of these imaging facilities.

Aims

Since Magnetic Resonance Imaging (MRI) is widely available as compared to bone scan or PET scan; a double blind study was undertaken to see if whole body imaging with MRI can give an idea of skeletal metastases.

Method

Diffusion weighted whole body Magnetic Resonance Imaging with background body signal suppression (DWIBS) was performed using 1.5 Tesla (T) MRI on histopathologically proven cases of carcinoma of breast within two months of mastectomy and followed up after a year of surgery. Similarly bone scan was also performed in these patients.

Results

DWIBS MRI demonstrated the presence and extent of bone metastases in 10 out of a total 18 patients included in study while bone scan could demonstrate them in only three cases. A highly significant difference between proportions of the skeletal metastases detected by whole body DWIBS-MRI than that by bone scan at one year follow-up. (i.e. p<0.01, z=2.66) was seen.

Conclusion

DWIBS MRI scores high in demonstrating skeletal metastases. Further comparative studies are necessary to evaluate if DWIBS can replace bone scan or PET scan.     

乳腺疾病磁共振扫描方案的优化选择

探讨磁共振多种扫描序列及方法诊断乳腺良、恶性疾病的应用价值,旨在为临床确定最优磁共振乳腺扫描方案。对42例乳腺疾病患者分别进行磁共振平扫和动态增强扫描及部分DWI、DWIBS检查,与手术病理结果对照,分析各种方法诊断价值及临床意义。多数病灶在磁共振平扫无特征性价值,联合动态增强各项标准诊断乳腺癌的敏感度为95.8%,特异度87.9%,准确度为91.2%;恶性组ADC值明显低于良性组,差异有统计学意义(P<0.05),以ROC曲线确定的诊断阈值为1.542×10-3mm2/s。以此值作为良、恶性判断界值,敏感度83.3%,特异度85.7%,诊断效果较好。5例DWIBS检查,观察到淋巴结转移及病灶远处转移灶,敏感性很高,适合乳腺多病变中心的观察及乳腺肿瘤的筛检和乳腺癌患者治疗前后的评估。时间-信号强度曲线、峰值时间及早期增强率,DWI在鉴别乳腺良、恶性病变方面具有较高的敏感性和特异性,DWIBS亦具有较高的敏感性,结合各种扫描方法的良恶性评判标准,对良、恶性病变的诊断及鉴别诊断有重要价值,且优化出临床最佳磁共振乳腺扫描方案。     

全身磁共振背景抑制扩散成像在直肠癌术前分期中的应用价值

目的探讨全身磁共振背景抑制扩散加权成像(DWIBS)对直肠癌术前分期的应用价值。资料与方法对39例经肠镜证实的直肠癌患者,术前行全身磁共振DWIBS检查,以直肠癌原发灶病理结果为标准将本组资料分为T2、T3、T4三组,分析原发灶DWIBS上肿瘤信号强度、表观扩散系数(ADC)值、肠壁病变厚度、肠壁受累长度、肿瘤侵犯肠周径的情况五个指标在各组间的差异,及其与T分期的相关性。通过全身DWIBS图像作出术前NM分期,然后与术后NM病理分期结果进行对照,判断DWIBS对直肠癌NM分期的准确性、特异性及敏感性。结果全身DWIBS对直肠癌原发灶检出的敏感性为100%,准确性为100%,DWIBS上所显示的肠壁病变厚度和肠周径侵犯程度在各分期间有显著差异(P<0.05),且两者与T分期均有显著相关性(rs=0.427,P<0.05;rs=0.384,P<0.05);原发灶肿瘤信号强度、ADC值、肠壁受累长度在各分期间均无显著差异(P>0.05)。DWIBS对N分期诊断的总体准确性为84.61%;对N0期诊断的敏感性为85.71%,特异性为83.33%,N1期诊断的敏感性为70.00%,特异性为89.66%,N2期诊断的敏感性为100%,特异性为80.65%。对M期诊断的敏感性及准确性均为100%。结论全身DWIBS对直肠癌NM分期的诊断敏感性较高,是显示转移性淋巴结及远处转移病灶的一种有效检查方法。全身DWIBS对直肠癌原发灶检出的准确性及敏感性很高,但在T分期中的应用有一定的限度,结合常规MRI序列有助于提高T分期的准确性。     

MR-DWIBS成像在宫颈癌临床分期中的作用

目的探讨磁共振背景抑制体部弥散加权成像、T2-脂肪抑制序列在宫颈癌临床分期中的价值，着重比较各序列在病灶检出中的作用及平均阅片时间。方法回顾性分析50例临床病理证实的宫颈癌术前MR常规平扫、T2-SPAIR以及DWIBS、增强资料。分组阅片，比较T2-SPAIR、DWIBS的敏感性及各组平均阅片时间。结果50例中，病灶总数为73。SPAIR组检出病灶数64，检出率88％，诊断符合率约90％，其平均阅片时间约18min。DWIBS组检出病灶数85，检出率100％，诊断符合率85％，其平均阅片时间约14min。“SPAIR＋DWIBS”组全部检出病灶并正确诊断，检出率、诊断符合率均100％，其平均阅片时间约8min。结论DWIBS在病灶检出方面敏感性高，结合T2-SPAIR能大大提高病灶检出率以及诊断正确率，从而提高临床分期的准确性。