LIPID-POOR ADRENAL MASSES: EVAL W/ DUAL ECHO CHEMICAL SHIFT MR IMAGING

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 肾上腺肿瘤在普通人群中很常见。由于横断面成像技术的广泛使用，这类肿瘤经常被偶然发现。在因与肾上腺无关的原因而接受CT扫描的患者中，约有0.35%-4.36%的人发现肾上腺肿瘤，并且这些肿瘤的发生率随着年龄的增加而增加。 大多数肾上腺肿瘤是无害的，可以单独治疗。因此，有必要对这些肿瘤进行定性，以避免不必要的手术或诊断程序。良性肾上腺肿瘤将进一步称为“肾上腺腺瘤”。许多肾上腺腺瘤不需要静脉注射造影剂，通过显示脂肪含量，在计算机断层扫描上就能很容易地识别出来。脂肪通常见于良性肾上腺肿瘤，在恶性肾上腺病变中很少见。然而，有一种肾上腺腺瘤亚群，即所谓的低脂肾上腺腺瘤，其脂肪含量太低，很难被发现。这种病变构成了一个严重的诊断问题，特别是在有恶性肿瘤病史的患者中。这些病变的确切特征通常是通过增强CT来实现的，这涉及到暴露于电离辐射和与使用含碘造影剂相关的风险。这些风险包括可能的对比剂过敏和对功能不全的肾脏的毒性损害。碘造影剂相关肾损害与肾功能和造影剂剂量相关。 磁共振成像是确定肾上腺肿块的有效替代方法。它不涉及电离辐射或静脉注射碘化造影剂。一种名为化学位移的技术被用于磁共振成像中，以确定肾上腺病变的特征。这项技术利用成像技术成像一定体积的组织中脂肪和水的相加和相减信号。虽然化学位移磁共振成像在诊断高脂肪含量的腺瘤方面与非增强CT一样好，但对于非增强CT无法描述的脂肪含量最低的肾上腺腺瘤的诊断价值，尚无共识。这在一定程度上是由于解决这个问题的旧研究中使用的过时技术。磁共振成像技术的进步，使用专门的腹部成像线圈和新的序列，可以检测出肾上腺病变中的少量脂肪。一种名为双回波梯度回波的新MRI序列，可以在一次屏气中获得，有助于消除肾上腺肿瘤脂肪测量不准确的潜在来源，如配准错误伪影。到目前为止，还没有研究发表评估双回波化学位移磁共振成像的准确性，以表征脂质缺乏的肾上腺病变。我们计划招募18岁或18岁以上患有肾上腺肿块并接受肾上腺专用CT检查的男性和女性。这些患者将接受MRI扫描，通常是15-20分钟的扫描，没有静脉造影剂。 如果双回波化学位移磁共振成像被证明是一种准确的成像工具，可以识别非增强CT无法可靠识别的低脂肪含量的肾上腺腺瘤，患者将受益于这种成像方法的优势，包括缺乏电离辐射，以及没有肾毒性和对碘化静脉造影剂过敏的风险。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Tumors of the adrenal glands are common in the general population. As a result of the widespread use of cross sectional imaging techniques, such tumors are often incidentally detected. Adrenal tumors are found in approximately 0.35% - 4.36% of patients who undergo CT imaging for reasons unrelated to the adrenal glands, and the incidence of these tumors increases with age. The majority of adrenal tumors are harmless, and can be left alone. Therefore, it is necessary to characterize these tumors to avoid unnecessary surgery or diagnostic procedures. Benign adrenal tumors will be further referred to as "adrenal adenomas". Many adrenal adenomas can be easily identified on computed tomography without the use of intravenous contrast material, by demonstrating their fat content. Fat is typically seen in benign adrenal tumors and is rare in malignant adrenal lesions. There is, however, a subgroup of adrenal adenomas, the so-called lipid poor adrenal adenomas, whose fat content is too low to be easily detected. Such lesions pose a serious diagnostic problem, especially in patients with history of malignancy. Definitive characterization of such lesions is often achieved with contrast enhanced CT, which involves exposure to ionizing radiation and the risks associated with the use of iodinated contrast medium. Such risks include possible contrast allergy and toxic impairment of marginally functioning kidneys. Iodinated contrast related kidney impairment is kidney function and contrast dose dependent. MR imaging is an effective alternative method for characterizing adrenal masses. It does not involve ionizing radiation or use of intravenous iodinated contrast material. A technique called chemical shift is used in MR imaging to characterize adrenal lesions. This technique exploits imaging the additive and subtracted signal of fat and water in a volume of tissue. While chemical shift MR imaging is as good as non-contrast CT for diagnosing adenomas with high fat content, there is no consensus regarding its utility for characterizing adrenal adenomas with minimal fat content that cannot be characterized by non-contrast CT. This in part is due to the outdated techniques used in older studies addressing this subject. Technical advances in MR imaging with the use of specialized coils for abdominal imaging, and new sequences, allow detection of small amounts of fat in adrenal lesions. A new MRI sequence called the Dual Echo gradient echo, which can be acquired in a single breath-hold, helps eliminate potential sources for imprecise measurements of fat in adrenal tumors, such as misregistration artifacts. So far, no studies have been published to evaluate the accuracy of dual echo chemical shift MR imaging for characterizing lipid poor adrenal lesions. We plan to recruit men and women 18 years of age or older with adrenal masses who have undergone a dedicated CT of the adrenal gland. These patients will undergo an MRI scan, usually 15-20 minute scan without intravenous contrast. If dual echo chemical shift MR imaging proves to be an accurate imaging tool for identifying adrenal adenomas with low fat content that cannot be reliably identified by non-contrast CT, patients will benefit from the advantages of this imaging method including the lack of ionizing radiation, and absence of risk of nephrotoxicity and allergy to iodinated intravenous contrast material.'