Abstract

BACKGROUND:

Inchworm sign is a finding on diffusion-weighted magnetic resonance imaging (DWI-MRI) and is used to better stratify T-staging in muscle invasive (MIBC) and non-muscle-invasive bladder cancer (NMIBC). An uninterrupted low submucosal signal on DWI, defined as inchworm sign (IS), indicates NMIBC.

OBJECTIVE:

We aimed to define the diagnostic accuracy of IS in primary bladder cancer, as well as find agreement between the urologists and the radiologist.

METHODS:

Between December 2018 and December 2020, we retrospectively analyzed 95 primary bladder cancer patients who had undergone multiparametric-MRI before transurethral resection. Patients with former bladder cancer history, tumors smaller than 10 mm, and MRI without proper protocol, as well as patients who did not attend follow-up, were excluded. In total, 71 patients’ images were evaluated by a genitourinary specialist radiologist and two urologists. Sensitivity, specificity, positive and negative predictive values of IS and VI-RADS in differentiating MIBC and NMIBC, and interreader agreement between the radiologist and urologists were analyzed.

RESULTS:

During follow-up, 38 patients (53.5%) were IS-positive, while 33 patients (46.5%) were negative. Among the 33 patients with negative IS, 14 patients (42.4%) had MIBC. Meanwhile, two out of the 38 IS-positive patients (5.3%) had MIBC (p = 0.00). Sensitivity, specificity, and positive and negative predictive values of IS in predicting MIBC were 87.5%, 63.6%, 41.2%and 94.6%, respectively. The interobserver agreement between the urologists and radiologist was almost perfect ( _K  = 0.802 and _K  = 0.745)

CONCLUSION:

The absence of IS on DWI is useful in differentiating MIBC from NMIBC. It is a simple finding that can be interpreted by urologists.

中文翻译：

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弥散加权 MRI 尺蠖征鉴别肌层浸润性膀胱癌的准确性

 抽象的

 背景：

尺蠖征是弥散加权磁共振成像 (DWI-MRI) 的发现，用于更好地对肌层浸润性膀胱癌 (MIBC) 和非肌层浸润性膀胱癌 (NMIBC) 的 T 分期进行分层。 DWI 上不间断的低粘膜下信号定义为尺蠖征 (IS)，表明 NMIBC。

 客观的：

我们的目的是确定 IS 在原发性膀胱癌中的诊断准确性，并在泌尿科医师和放射科医师之间达成一致。

 方法：

2018年12月至2020年12月期间，我们回顾性分析了95名在经尿道切除术前接受多参数MRI的原发性膀胱癌患者。有膀胱癌病史、肿瘤小于 10 毫米、没有适当方案的 MRI 的患者以及未参加随访的患者被排除在外。一名泌尿生殖专业放射科医生和两名泌尿科医生总共对 71 名患者的图像进行了评估。分析了 IS 和 VI-RADS 在区分 MIBC 和 NMIBC 方面的敏感性、特异性、阳性和阴性预测值，以及放射科医师和泌尿科医师之间的读者间一致性。

 结果：

随访期间，38 名患者（53.5%）IS 阳性，33 名患者（46.5%）阴性。在 33 名 IS 阴性患者中，14 名患者（42.4%）患有 MIBC。同时，38 名 IS 阳性患者中的 2 名 (5.3%) 患有 MIBC ( p = 0.00)。 IS预测MIBC的敏感性、特异性、阳性预测值和阴性预测值分别为87.5%、63.6%、41.2%和94.6%。泌尿科医生和放射科医生之间的观察者间一致性几乎是完美的（ _K = 0.802 和_K = 0.745）

 结论：

DWI 上缺乏 IS 有助于区分 MIBC 和 NMIBC。这是一个简单的发现，可以由泌尿科医师解释。