肾上腺腺瘤与非腺瘤的CT鉴别诊断

目的 探讨肾上腺腺瘤与非腺瘤的CT鉴别诊断价值.方法 回顾性分析经手术和随访证实的56例(58个病灶)肾上腺肿瘤的CT表现及病理组织学特征,患者均行CT平扫及1 min、5 min增强扫描,对诊断参数进行分析并对照病理组织学表现,对肾上腺肿瘤做出正确的诊断.结果 腺瘤与非腺瘤在CT平扫及增强后1 min、5 min的CT值、相对廓清率和绝对廓清率的差异均有统计学意义(P＜0.05),以平扫时CT≤19 HU,延时5 min时CT≤46 HU,绝对廓清率≥63%,相对廓清率≥31%为阈值相结合作为诊断标准时,诊断腺瘤或乏脂性腺瘤的敏感性分别为96%或86%.结论 以肿瘤平扫及增强后的CT值与肿瘤的廓清率作为联合标准,对腺瘤(包括乏脂性腺瘤)与非腺瘤的鉴别诊断有较高的价值.     

肾上腺腺瘤和非腺瘤的动态增强CT检查

目的采用规范化的动态增强CT检查技术,对大样本病例进行深人地多角度评价．使肾上腺肿瘤动态增强CT检查能够在临床上广泛应用。资料与月法经手术和临床证实的70例共79个肾上腺肿块（腺瘤44个．非腺瘤35个）分别以相同的扫描条件行CT平扫和动态增强检查（静脉注人对比剂后30s开始扫描）,然后延时1、2、3、5．7min扫描。剂量1．2ml／kg体重,注射流率2．5ml／s。分析评价肾上腺肿块的T—D曲线和廓清率Wash（相对廓清率Washr和绝对廓清率Washa）。结果T—D曲线分为5种类型,即A、B、C、D和E各型。腺瘤的特征曲线为A、C型,非腺瘤为B、D、E型（P=0．000）。Washr和Washa于腺瘤和非腺瘤间存在显著性差异（P=0．000）,腺瘸的Washr和Washa均高于非腺瘤,并且Washr诊断效果优于Washa。7min延时点诊断价值较大．Washr≥34HU提示为腺瘤．反之提示为非腺瘤。结论肾上腺CT动态增强检查能够对腺瘤和非腺瘤尤其对乏脂性腺瘤与非腺瘤的鉴别诊断具有较大价值。     

肿瘤廓清率在动态增强MRI检查中对肾上腺肿瘤的鉴别诊断价值

目的　探讨应用动态增强MRI检查技术 ,以肿瘤的廓清率为标准 ,再结合该时间点的信号增加比 ,对肾上腺腺瘤与非腺瘤进行鉴别诊断的临床价值。方法　 3 6例共 41个肾上腺肿瘤均先行常规SE序列T1 WI及T2 WI成像 ,再利用屏气快速多层面破坏性梯度回波序列 (fastmultiplanarspoiledgradient-echo ,FMPSPGR)行轴位扫描 ,先平扫 ,再以同样条件行MRI动态增强检查 ,观察病变的增强程度并分别测量肿瘤实质部分的信号值。分别比较腺瘤与非腺瘤的廓清率及信号增加比 ,明确其鉴别诊断价值。结果　延时 5min并以廓清率 2 2 %为阈值时 ,诊断腺瘤的敏感性 74% ,特异性 73 % ,准确性 73 % ;若将延时 5min时肿瘤的廓清率 (2 2 % )与信号增加比(<0 .48)相结合 ,则诊断腺瘤的敏感性、特异性、准确性明显提高 ,分别为 95 %、91%、93 %。结论　利用动态增强检查技术 ,以肿瘤的廓清率为标准 ,再结合该时间点的信号增加比 ,可在最短的时间内提高肾上腺腺瘤与非腺瘤的鉴别诊断水平     

肾上腺腺瘤和非腺瘤动态增强CT表现与血管生成相关性的初步研究

目的探讨肾上腺腺瘤和非腺瘤血管生成[微血管密度（MVD），血管内皮生长因子（VEGF）]特点与动态增强CT表现的相关性，以阐述其动态增强机制。方法经手术病理证实的42例46个肾上腺肿块（腺瘤23个、非腺瘤18个、增生结节5个）均行动态增强CT检查和病理学检查。首先评价肾上腺腺瘤和非腺瘤动态增强CT表现，而后分析肾上腺肿块动态增强CT表现特征[时间-密度（T-D）曲线、廓清率（Wash）]与血管生成之间的相关关系。结果腺瘤与非腺瘤间T—D曲线类型和7min延时点相对廓清率（Washr）和绝对廓清率（Washa）差异均存在统计学意义（P=0．000）。肾上腺肿块T—D曲线廓清迅速组（A、C型）与廓清缓慢组（B、D、E型）间、7min延时点Washr≥34％组与〈34％组间、Washai≥43％组与〈43％组间MVD、VEGF表达水平差异均有统计学意义（P〈0．05）。肿块廓清曲线为A、C型，和（或）Washr≥34HU，和（或）Washai≥43％组均提示为腺瘤，反之提示为非腺瘤。T—D曲线廓清迅速组、7min延时点Washri≥34％组和Washa≥143％组MVD、VEGF表达水平分别高于廓清缓慢组、〈34％组和〈43％组；由此提示动态增强CT表现特征与MVD、VEGF表达存在相关性。另一方面，腺瘤和非腺瘤间MVD和VEGF表达存在显著不同。结论MVD和VEGF可能是导致腺瘤和非腺瘤具有不同的T—D曲线类型和廓清率的主要因素之一。     

动态增强MRI检查对于肾上腺腺瘤与非腺瘤的鉴别诊断价值

MRI检查能清晰地显示肿瘤的大小、形态、与周围组织的关系及有无淋巴结转移，也能反映出肿瘤的某些组织学特征，而且由于MRI检查的多方位、多参数、多序列成像的特点，为研究应用各种不同的检查方法鉴别肾上腺腺瘤与非腺瘤提供了可能。就动态增强MRI检查技术在鉴别诊断肾上腺腺瘤与非腺瘤时的应用方法及价值进行综述。     

ROC曲线分析在肾上腺肿瘤的动态增强CT、MRI检查中的应用

目的 探讨应用受试者操作特性(ROC)曲线评价以肿瘤廓清率为标准利用动态增强CT、MRI检查鉴别肾上腺肿瘤的价值及其这两种检查方法的相关性.资料与方法 25例共28个肾上腺肿瘤均先行平扫及动态增强CT检查,之后再行平扫及动态增强MRI检查,以肿瘤的廓清率为鉴别标准,利用ROC曲线对所选取的诊断标准进行评价,通过ROC曲线下面积(AZ值)来确定所选择诊断标准的价值,并对这两种检查方法行相关性分析.结果 在延迟5～35 min时间点,以肿瘤的廓清率为标准对肾上腺肿瘤的鉴别诊断价值较大(AZ值均在0.7以上),两者之间差异无统计学意义(P＞0.05),再通过对两组变量,即两种检查方法中的廓清率进行分析,认为在延迟5～50 min时,两组变量对肾上腺肿瘤的鉴别诊断均具有高度相关性.结论 以肿瘤的廓清率为诊断标准,无论是利用动态增强CT还是动态增强MRI检查,均可提高肾上腺肿瘤的鉴别诊断水平,两种检查方法对于肾上腺肿瘤的鉴别诊断价值差异无统计学意义,且检查结果具有一致性.     

CT值在肾上腺腺瘤诊断中的应用价值及其阈值选择

目的：评价平扫CT值在肾上腺腺瘤诊断中的应用价值,并优化选择鉴别阈值。方法：回顾性分析经手术及病理证实的肾上腺肿瘤61例（63个病灶）,其中腺瘤33个,非腺瘤30个,分别测量肿瘤的平扫CT值并计算不同CT值阈值鉴别腺瘤与非腺瘤的敏感性、特异性、准确性、阳性预测值及阴性预测值。结果：33个腺瘤平扫CT值-9.0～42.6HU（10.6&#177;11.4）HU,30个非腺瘤平扫CT值18.2～48.7HU（36.1&#177;7.3）HU,两者的平均平扫CT值差异有显著性意义（t=10.436,P=0.000）。使用15HU作为鉴别域值时诊断腺瘤的敏感度73%,特异度100%,准确度86%,阳性预测值100%,阴性预测值77%;而使用20和25HU作为域值时的敏感度更高,分别为85%和91%,但特异度降低,分别为93%和90%。结论：平扫CT值在肾上腺腺瘤鉴别诊断上有重要价值,以≤15HU作为腺瘤的诊断标准是比较合适的,特异度高,敏感度也相对较高。     

动态增强MRI检查对于肾上腺腺瘤与非腺瘤的鉴别诊断价值

MRI检查能清晰地显示肿瘤的大小、形态、与周围组织的关系及有无淋巴结转移,也能反映出肿瘤的某些组织学特征,而且由于MRI检查的多方位、多参数、多序列成像的特点,为研究应用各种不同的检查方法鉴别肾上腺腺瘤与非腺瘤提供了可能.就动态增强MRI检查技术在鉴别诊断肾上腺腺瘤与非腺瘤时的应用方法及价值进行综述.     

增强MRI时间-信号增强率曲线对肾上腺肿瘤的鉴别价值

目的 :以肿瘤的时间 信号增强率曲线作为诊断标准 ,进一步证实Gd DTPA动态增强MRI检查技术对肾上腺肿瘤的鉴别诊断价值。方法 :3 6例共 41个肾上腺肿瘤 ,腺瘤 19例共 19个 ,非腺瘤 17例共 2 2个。所有肿瘤均先行常规SE序列T1 W和T2 W成像 ,选定肿瘤中心层面定位后 ,再利用屏气快速多层面破坏性梯度回波序列 (FMPSPGR)行轴位扫描 ,先平扫 ,再以同样条件行MRI动态增强检查 ,即静注Gd DTPA ,自注药后 0 .5min开始扫描 ,之后分别在 60min内共 17个时间点 ,以同等条件延时扫描 ,观察病变的增强程度 ,并分别测量其实质部分的信号值。计算肿瘤的信号比、最大信号增加比、增强率 ,再根据随时间延时肿瘤增强率的变化绘制曲线 ,比较肾上腺肿瘤间的时间 信号增强率曲线有无差异 ,并明确其对肾上腺肿瘤的鉴别诊断价值。结果 :Ⅰ型时间 信号增强率曲线具有高度特异性 ,只有大多数神经源性肿瘤符合此增强特点 ,对区分腺瘤与其它类型的非腺瘤无诊断价值 ;以Ⅲ型或Ⅳ型曲线为标准诊断恶性肿瘤的准确率均不高 ,有 5 0 %的恶性肿瘤无法确诊 ;而以Ⅱ型时间 信号增强率曲线为标准较前 3种曲线更有助于肾上腺肿瘤的鉴别诊断 ,即以早期增强 ,延时 9min内肿瘤增强率下降程度超过肿瘤最大增强率的 5 0 %为诊断腺瘤的标准 ,敏     

动态增强CT检查对于肾上腺腺瘤与非腺瘤的鉴别诊断价值

随着CT技术的普遍应用,肾上腺肿瘤的检出率有了很大提高.如何准确判断腺瘤与非腺瘤是腹部影像学检查的研究重点问题之一.就动态增强CT检查技术在肾上腺肿瘤中的应用方法及其价值进行综述.     

Delayed enhanced CT of lipid-poor adrenal adenomas

OBJECTIVE. Although representing a minority of adrenal adenomas, the lipid-poor variety cannot be accurately identified on unenhanced CT or chemical shift MR imaging. We compared the delayed contrast-enhanced CT features of lipid-poor adenomas with those of lipid-rich adenomas and of adrenal nonadenomas to determine whether there were differences in the washout features between these groups of lesions. SUBJECTS AND METHODS. Eighteen proven lipid-poor adenomas, 56 lipid-rich adenomas, and 40 adrenal nonadenomas underwent CT before, immediately after, and 15 min delay after IV contrast injection. Region-of-interest measurements were made of all adrenal lesions at the three time points. The degree of enhancement, enhancement washout, percentage enhancement washout, and relative percentage enhancement washout were calculated for each adrenal mass. Pooled data were analyzed statistically. Optimal threshold values for diagnosing adrenal adenomas were also determined. RESULTS. The mean CT attenuation of lipid-poor adenomas was significantly higher than that of lipid-rich adenomas at all three phases but not significantly different from that of nonadenomas. The mean percentage enhancement washout on images obtained 15 min after administration of contrast material was similar for lipid-rich and lipid-poor adenomas but was significantly higher than that of nonadenomas. The mean relative percentage enhancement washout was significantly different among all three groups. CONCLUSION. Lipid-poor adenomas cannot be differentiated from adrenal nonadenomas on the basis of a single mean attenuation value. However, lipid-poor adrenal adenomas show enhancement and enhancement washout features nearly identical to lipid-rich adenomas and can be distinguished from nonadenomas on the basis of a percentage washout threshold value of 60% and a relative percentage washout of 40%.     

Adrenal masses: characterization with combined unenhanced and delayed enhanced CT

PURPOSE: To assess the accuracy of a dedicated adrenal computed tomographic (CT) protocol. MATERIALS AND METHODS: One hundred sixty-six adrenal masses were evaluated with a protocol consisting of unenhanced CT, and, for those with attenuation values greater than 10 HU, contrast material-enhanced and delayed enhanced CT. Attenuation values and enhancement washout calculations were obtained. An adenoma was diagnosed if a mass had an attenuation value of 10 HU or less at unenhanced CT or a percentage enhancement washout value of 60% or higher. RESULTS: The final diagnosis was adenoma in 127 masses and non-adenoma in 39. Masses measuring more than 10 HU on unenhanced CT scans were confirmed at biopsy (n = 28) or were examined for stability or change in size at follow-up CT performed at a minimum interval of 6 months (n = 33). Thirty-six (92%) of 39 non-adenomas and 124 (98%) of 127 adenomas were correctly characterized. The sensitivity and specificity of this protocol were 98% and 92%, respectively. This protocol correctly characterized 160 (96%) of 166 masses. CONCLUSION: With a combination of unenhanced and delayed enhanced CT, nearly all adrenal masses can be correctly categorized as adenomas or non-adenomas.     

Characterization of indeterminate (lipid-poor) adrenal masses: use of washout characteristics at contrast-enhanced CT

PURPOSE: To determine whether computed tomographic (CT) scans and attenuation measurements on contrast material-enhanced and nonenhanced CT scans could be used to characterize adrenal masses, in particular, to characterize these lesions by using adrenal washout characteristics at contrast-enhanced CT. MATERIALS AND METHODS: Eighty-six patients (49 men, 37 women; age range, 29-86 years; mean age, 72 years) with 101 adrenal lesions depicted at contrast-enhanced CT underwent delayed (mean, 9 minutes) enhanced scanning. Seventy-eight patients also underwent nonenhanced CT. Mean diameter of the benign lesions was 2.1 cm (range, 1.0-4.2 cm); mean diameter of the malignant lesions was 2.3 cm (range, 1.0-4.1 cm). Region-of-interest measurements were obtained at nonenhanced, dynamic enhanced, and delayed enhanced CT and were used to calculate a relative percentage washout as follows: 1 - (Hounsfield unit measurement on delayed image / Hounsfield unit measurement on dynamic image) x 100%. RESULTS: Ninety-nine of 101 lesions were correctly characterized as benign or malignant with a relative percentage washout threshold of 50% on delayed scans; benign lesions demonstrated more than 50% washout; and malignant lesions, less than 50% washout. Two benign lesions demonstrating less than 50% washout were characterized as benign by using conventional CT. CONCLUSION: Calculation of relative percentage washout on dynamic and delayed enhanced CT scans may lead to a highly specific test for adrenal lesion characterization, reduce the need for, and possibly obviate, follow-up imaging or biopsy.     

Comparison of delayed enhanced CT and 18F-FDG PET/CT in the evaluation of adrenal masses in oncology patients

OBJECTIVE: To retrospectively compare delayed enhanced computed tomography (CT) and 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET)/CT (PET/CT) evaluating adrenal masses in oncology patients undergoing both examinations. METHODS: Twenty adrenal masses in 14 patients were retrospectively included. For delayed enhanced CT, a metastasis was diagnosed if a mass had an absolute percentage loss of enhancement value of less than 60%. For PET/CT, a metastasis was diagnosed if a mass had FDG uptake equal to or greater than that of the liver. RESULTS: The adrenal masses were confirmed as 8 metastases and 12 adenomas by pathological examinations in 5 patients and follow-up CT examinations in 9 patients. The sensitivity and specificity for adenoma at delayed enhanced CT were all 100% and were 88 (7/8) and 75% (9/12) for PET/CT, respectively. Delayed enhanced CT correctly characterized 1 more metastasis and 3 more adenomas than PET/CT. CONCLUSIONS: Delayed enhanced CT might characterize adrenal masses in oncology patients more exactly than PET/CT.     

Computed tomographic histogram analysis in the diagnosis of lipid-poor adenomas: comparison to adrenal washout computed tomography

OBJECTIVE: To evaluate the ability of computed tomographic histogram analysis to diagnose lipid poor adenoma in comparison with adrenal washout computed tomography (CT). MATERIALS AND METHODS: Adrenal CT washout examinations performed during a period from January 2000 to July 2005 were reviewed. Computed tomographic histogram analysis was performed on the unenhanced component of the study, and sensitivity was assessed at thresholds of more than 5% and 10% negative pixels. Liver and spleen were used to represent the control/nonadenoma group. Computed tomographic noise was measured recording standard deviation (SD) of mean CT attenuation in adrenal, liver, and spleen. RESULTS: Twenty-four lipid-poor adenomas included exhibited more than 60% absolute enhancement washout (range, 60%-79%, mean, 69%) and remained stable for a period greater than 6 months. At threshold of more than 5% or 10% negative pixels CT histogram analysis yielded sensitivities of 91.6% and 70.8%, respectively, with 100% specificity. The mean SDs of adrenal, liver, and spleen were 18.2, 16.4 and 15, respectively. These differences in the mean SD were much smaller compared with the differences in the percentage of negative pixels in adrenal, liver, and spleen of 12.75%, 0.75%, and 0.25%, respectively. CONCLUSIONS: Computed tomographic histogram analysis has good potential in the diagnosis of lipid-poor adenoma and can reduce the need to perform adrenal washout CT.     

Comparison of delayed enhanced CT and chemical shift MR for evaluating hyperattenuating incidental adrenal masses

PURPOSE: To retrospectively compare the accuracy of delayed enhanced computed tomography (CT) and chemical shift magnetic resonance (MR) imaging for characterizing hyperattenuating adrenal masses at CT, with either follow-up imaging or pathologic review as the reference standard. MATERIALS AND METHODS: The institutional review board approved this retrospective study with a waiver of patient informed consent. Forty-three hyperattenuating adrenal masses (>10 HU) on unenhanced CT images were found in 34 patients (23 men and 11 women; mean age, 52.7 years) by reviewing radiologic reports. These lesions were retrospectively analyzed with delayed enhanced CT and chemical shift MR. The diagnostic accuracy of CT by using absolute percentage loss of enhancement (PLE) and relative PLE and of chemical shift MR by using adrenal-to-spleen ratio (ASR) or signal intensity index (SII) were obtained to determine which modality was more accurate for lipid-poor adenoma. For CT, an adenoma was diagnosed if a mass had an absolute PLE greater than 60% and a relative PLE greater than 40%. For MR, an adenoma was diagnosed if a mass had an ASR of 0.71 or an SII greater than 16.5%. McNemar test was used to compare diagnostic performance of CT and MR. RESULTS: Hyperattenuating adrenal masses included 37 adenomas and six nonadenomas. The sensitivity, specificity, and accuracy for adenoma at CT were 97% (36 of 37), 100% (six of six), and 98% (42 of 43), respectively, and at MR were 86% (32 of 37), 50% (three of six), and 49% (21 of 43), respectively. CT helped confirm five more adenomas and three more metastatic tumors than did MR. However, there was no significant difference for diagnostic accuracy between these two imaging modalities (P>.05) CONCLUSION: Delayed enhanced CT can characterize additional hyperattenuating adrenal masses that cannot be characterized with chemical shift MR.     

Adrenal incidentaloma detected on triphasic helical CT: evaluation with modified relative percentage of enhancement washout values

The aim of this study is to retrospectively assess adrenal incidentalomas detected by triphasic helical CT using modified relative percentage of the enhancement washout (mRPEW) values. 42 adrenal incidentalomas in 35 patients were detected on CT and confirmed by either pathological examination or follow-up CT examination. The mRPEW values were calculated using the attenuation values of the adrenal masses seen on the images from portal phase and delayed phase CT performed 3 min after intravenous injection of contrast material. The diagnostic accuracy of an adenoma was obtained using the mRPEW values. The final diagnosis was an "adenoma" and a "metastasis" in 9 and 33 cases, respectively. The mRPEW values of the adenomas and metastases ranged from 5.8% to 59.4% (26.1+/-15.5%) and from -18.8% to 25% (6.4+/-11.7%), respectively (p<0.05). An mRPEW value of 20% yielded the best accuracy of 88% (37/42) for an adenoma. mRPEW values >25% and < or =5% had a positive predictive value of 100% (3/3) and a negative predictive value of 100% (15/15), respectively. In conclusion, a substantial number of adrenal incidentalomas may be characterized using the mRPEW values from triphasic helical CT without the need for dedicated adrenal CT.     

Radiologie der Nebennieren

An important principle of diagnostic imaging of the adrenal glands is to characterize an adrenal mass as an adenoma using computed tomography (CT) or magnetic resonance imaging (MRI) techniques. Most techniques exploit the fact that typical adrenal adenomas are lipid-rich so that lipid-poor adenomas, however, remain a diagnostic problem. A CT attenuation ≤?10 HU, more than 10% negative pixels as demonstrated by histogram analysis, an absolute washout of more than 60%, a relative washout of more than 40% and a signal drop of more than 20% in opposed-phase images are characteristic for adrenal adenomas. Endocrine dysfunction is diagnosed biochemically and not by means of imaging but are necessary to localize a functioning tumor. An important principle is to combine anatomical with functional imaging studies. Percutaneous biopsy of adrenal glands is only indicated when an adrenal mass is the only potential metastasis of a diagnosed primary tumor.     

Adrenal masses: CT characterization with histogram analysis method

PURPOSE: To evaluate a histogram analysis method for differentiating adrenal adenoma from metastasis at computed tomography (CT). MATERIALS AND METHODS: In a retrospective review of 2 years of clinical CT records, 223 adrenal adenomas in 193 patients (115 with contrast material-enhanced CT, 43 with unenhanced and enhanced CT, and 35 with unenhanced CT) and 31 metastases (25 patients with enhanced CT) were found. In 158 patients with adenomas at enhanced CT, diagnosis was based on stable mass size for more than 1 year (n = 135) and characteristic signal intensity decrease at chemical shift magnetic resonance imaging (n = 23). In 35 patients with adenomas at unenhanced CT, mean attenuation was 10 HU or less. Diagnosis of all metastases was based on rapid growth of a mass or new mass in less than 6 months in patients with cancer. Adrenal metastases with extensive necrosis were excluded. Histogram analysis was performed in a circular region of interest (ROI) for mean attenuation, number of pixels, and range of pixel attenuation for all pixels and for the subset of pixels with less than 0 HU ("negative" pixels). Correlation between mean attenuation and percentage negative pixels was calculated. RESULTS: Negative pixels were present in all 74 unenhanced adenomas with mean attenuation of 10 HU or less and in 14 of 16 unenhanced adenomas with mean attenuation above 10 HU. Of 184 enhanced adenomas, only 20 had mean attenuation of 10 HU or less, but 97 contained negative pixels (77 of these 97 masses had mean attenuation above 10 HU). Increase in percentage negative pixels was highly correlated with decrease in mean attenuation of both unenhanced and enhanced adenomas. None of the adrenal metastases had mean attenuation of 10 HU or less or contained negative pixels. CONCLUSION: The histogram method is far more sensitive than the 10-HU threshold method for diagnosis of adrenal adenomas at enhanced CT, with specificity maintained at 100%.