动态增强CT检查对肾上腺腺瘤与非腺瘤的鉴别诊断价值

目的探讨动态增强CT检查技术对肾上腺腺瘤与非腺瘤的鉴别诊断价值并优选出有意义的参数，以进一步明确两者的鉴别诊断标准。资料与方法对44例共49个肾上腺肿瘤先平扫再行动态增强CT检查，观察以肿瘤的CT绝对值、绝对开始廓清率及相对开始廓清率作为标准鉴别肾上腺腺瘤与非腺瘤的诊断价值。结果延时3min，以36％的绝对开始廓清率或35％的相对开始廓清率分别与CT绝对值58HU相结合作为标准，对腺瘤有较高的诊断价值，对于腺瘤中的乏脂质性腺瘤与非腺瘤的鉴别诊断也具有同样的价值。结论以肿瘤的廓清率与延时增强后的CT绝对值作为联合标准，能明显提高腺瘤的诊断价值。     

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     

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。     

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.     

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.     

MR化学位移成像诊断肾上腺腺瘤的研究

目的：研究MRI对肾上腺肿瘤的定性诊断价值。方法：对23个肾上腺腺瘤和35个其他肾上腺占位性病变的患者行SE序列T1WI、快速自旋回波（TSE）序列T2WI和化学位移成像（CSI）序列扫描。肿物直径8-92mm。计算并比较肿物与肝脏、脾脏和水模在反相位和同相位上的信号比值变化。结果：腺瘤组有20/23的病例肿物-脾脏信号比（ASR）＜0.59,而基人他占位性病变ASR均大于0.73。MR CSI序列诊断肾上腺腺瘤的敏感性为87%,特异性为100%。结论：MR化学位移成像对肾上腺腺瘤的定性诊断具有重要价值。     

MRI动态扫描对垂体微腺瘤的诊断价值

目的:探讨MRI动态扫描对垂体微腺瘤的诊断价值。材料与方法:垂体微腺瘤患者30例均经PHILIP 1.0 NT型MR机行常规矢状面、冠状面T_1WI和T_2WI检查,而后全部又经动态扫描。结果:本组30例的病灶在平扫中,T_1WI呈低信号、T_2WI呈高信号者25例;T_1WI呈等信号、T_2WI呈高信号者3例;T_1WI和T_2WI均呈等信号者1例及高信号者1例。微腺瘤形态征象有垂体柄偏斜(25例)、垂体中央向上膨隆(2例),鞍底下陷(2例),以及瘤内出血(1例),动态扫描后,病灶不增强而正常腺体增强且边界清楚者29例,仅有1例病灶内出血且边界不清楚。结论:MRI动态扫描对垂体微腺瘤的诊断敏感性显著高于平扫,而且它可完整地观察早期正常垂体的增强表现与垂体微腺瘤的增强延迟表现,因而,它有助于对垂体微腺瘤的准确定位,提高诊断准确率。     

肾上腺转移瘤的动态CT、MRI检查

目的 探讨动态增强CT及MRI检查对肾上腺转移瘤的鉴别诊断价值.方法 搜集资料完整的17例(共27个)肾上腺转移瘤,观察其大小、形态及强化特征,分析肿瘤廓清率对肾上腺转移瘤的鉴别诊断价值,并对2种检查(CT和MRI)方法进行相关性分析.结果 17例共27个肾上腺转移瘤中,63%肿块边缘不光滑且形态不规则,67%肿块增强后呈不均匀强化,所有肿块随时间延迟均呈轻、中度逐渐强化,达峰值后肿块内对比剂排空缓慢.在动态增强CT及MRI检查中,于延迟5 min肾上腺转移瘤的廓清率分别仅为12.7%和11.4%.2种检查方法在延迟5 min时相关性最大,相关系数0.819(P=0.024).结论动态增强CT及MRI检查对绝大多数肾上腺转移瘤可做出正确定位、定性诊断,有利于治疗方案的正确制订.     

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%.     

Discriminatory power of MRI for differentiation of adrenal non-adenomas vs adenomas evaluated by means of ROC analysis: Can biopsy be obviated?

The purpose of our study was to evaluate the discriminatory power of MRI in high-field magnet (1.5 T) for differentiation of adrenal non-adenomas vs adenomas assessing the following parameters separately and in combination: mean diameter of adrenal mass; previously described and new ratios as well as index calculated from signal intensity (SI) on SE T2-weighted images, chemical shift imaging (CSI), and Gd-DTPA-enhanced dynamic studies. One hundred eight adrenal masses (36 non-hyperfunctioning adenomas, 27 pheochromocytomas, 23 aldosterone-secreting adenomas, 20 malignant masses and 2 cortisol-secreting adenomas) in 95 patients were evaluated with SE sequences, CSI and Gd-DTPA dynamic studies. Indices and ratios of SI for all examined MRI methods were calculated and examined retrospectively for significance of differences between the groups with calculation of sensitivity and specificity. Receiver operating characteristics (ROC) analysis of calculated parameters in combination was performed. The multifactorial analysis of all four parameters, including size of the tumor, T2_liver index, CSI ratio reflecting lipid content in the tumor and Wo_max/last ratio reflecting maximal washout of contrast agent from the tumor had 100 % sensitivity and 100 % specificity in characterization of adrenal non-adenoma. The best performance of combination of mean tumor diameter with single MRI SI parameter was achieved in combination with T2_liver index for all adrenal masses (area under ROC 0.987) and CSI ratio for non-hyperfunctioning adrenal masses (area under ROC 0.991). Magnetic resonance imaging enables sensitive and specific diagnosis of adrenal non-adenoma. Received: 18 June 1998; Revised: 11 January 1999; Accepted: 5 May 1999     

Characterization of adrenal masses using MR imaging with histopathologic correlation.

OBJECTIVE: The purpose of this study was to evaluate the sensitivity, specificity, and accuracy of MR imaging in the characterization of adrenal masses by correlating imaging findings with histopathologic results. In addition, adrenal tumors that were of an indeterminate nature on MR imaging were analyzed. SUBJECTS AND METHODS: For 114 patients with 134 adrenal masses, MR findings were compared with histologic results. In all patients, MR imaging was performed using T2-weighted fast spin-echo imaging and unenhanced and gadolinium-enhanced T1-weighted spin-echo imaging. Chemical-shift imaging was performed in 92 patients and dynamic gadolinium-enhanced studies in 108 patients. Chemical-shift images were analyzed quantitatively and qualitatively, and dynamic gadolinium-enhanced studies were qualitatively assessed. RESULTS: The sensitivity of MR imaging in differentiating between benign and malignant adrenal masses was 91%, the specificity was 94%, and the accuracy was 93%. The diagnosis at MR imaging differed from that at histology in 12 (9%) of 134 patients. Results of quantitative analyses of chemical-shift imaging techniques showed significant differences between adenomas and nonadenomas (-36.0% versus -3.7%; p < .001). Qualitative analysis provided a similar diagnostic confidence compared with quantitative analysis. Both chemical-shift and dynamic gadolinium-enhanced studies proved to be unreliable in characterizing borderline tumors (epithelial tumors with high malignant potential). Moreover, such imaging failed to allow correct diagnosis of adenomas in two patients. CONCLUSION: The characterization of an adrenal mass can be made with high sensitivity and specificity using MR imaging. The increased reliance on MR imaging seems to be based mainly on findings from chemical-shift and dynamic gadolinium-enhanced studies. The need to perform histologic sampling of incidentally discovered adrenal masses may be reduced to some problematic lesions, which will remain during the era of MR imaging.     

Dynamic perfusion CT parameters and delayed contrast washout CT in characterization of adrenal tumors: A comparative study

Purpose

The study aims to compare the accuracy of washout and perfusion CT techniques in diagnosis of adrenal tumors.

Evaluation of adrenal masses in oncologic patients: dynamic contrast-enhanced MR vs CT

The CT examinations, precontrast gradient echo MR images, and fast contrast enhanced dynamic MR studies were evaluated in 44 patients with 52 adrenal masses and known malignant disease of different origin. Morphologic features (size, shape, attenuation, contour, and enhancement) on CT scans, signal intensity on T2-weighted MR images, and patterns of enhancement on Gd-DTPA enhanced dynamic MR studies were analyzed in all patients. With dynamic contrast enhanced studies with prolonged imaging up to 15 min after Gd-DTPA, masses with moderate enhancement and complete washout after 10 min were considered as adenomas. Computed tomography and plain MR had a sensitivity of 0.71 and 0.96, a specificity of 0.75 and 0.88, and overall accuracy of 0.56 and 0.71, respectively. Simultaneous use of precontrast MR and dynamic contrast enhanced studies led to an accurate diagnosis in 88% (sensitivity = 1.0, specificity = 0.91) and thus should be considered in oncologic patients with undetermined adrenal masses.     

Dynamic contrast enhanced MRI in the differential diagnosis of adrenal adenomas and malignant adrenal masses

OBJECTIVE: To evaluate the value of dynamic MR imaging in the differential diagnosis of adrenal adenomas and malignant tumors, especially in cases with atypical adenomas. MATERIALS AND METHODS: Sixty-four masses (48 adenomas, 16 malignant tumors) were included in this prospective study. Signal loss of masses was evaluated using chemical shift MR imaging. Five dynamic series of T1-weighted spoiled gradient echo (FFE) images were obtained, with the acquisition starting simultaneously with i.v. contrast administration (0-100 s) followed by a T1-weighted FFE sequence in the late phase (5th minute). Contrast enhancement patterns in the early (25th second) and late (5th minute) phase images were evaluated. For the quantitative evaluation, signal intensity (SI)-time curves were obtained according to the SIs on the 0th, 25th, 50th 75th and 100th second. Also, the wash-in rate, maximum relative enhancement, time-to-peak, and wash-out of contrast at 100 s of masses in both groups were calculated. The statistical significance was determined by Mann-Whitney U test. To evaluate the diagnostic performance of the quantitative tests, receiver operating characteristic (ROC) analysis was performed. RESULTS: Chemical shift MR imaging was able to differentiate 44 out of 48 adenomas (91.7%) from non-adenomas. The 4 adenomas (8.3%) which could not be differentiated from non-adenomas by this technique did not exhibit signal loss on out-of-phase images. With a cut-off value of 30, SI indices of adenomas had a sensitivity of 93.8%, specificity of 100% and a positive predictive value of 100%. On visual evaluation of dynamic MR imaging, early phase contrast enhancement patterns were homogeneous in 75% and punctate in 20,83% of the adenomas; while patchy in 56.25% and peripheral in 25% of the malignant tumors. On the late phase images 58.33% of the adenomas showed peripheral ring-shaped enhancement and 10.41% showed heterogeneous enhancement. All of the malignant masses showed heterogeneous enhancement. At the 25th second, the SIs and wash-in rates of the adenomas were significantly higher than those of the malignant masses (p=0.010). Time-to-peak enhancement of the malignant masses was significantly longer than that of the adenomas. With a cut-off value of 52.85 s, the time-to-peak enhancement had 87.5% sensitivity and 80% specificity. CONCLUSION: Chemical shift MR has a high sensitivity and specificity in the differential diagnosis of adenomas and malignant adrenal masses. However, taking into consideration only the atypical adenomas, chemical shift MRI is of no diagnostic value. Although the diagnostic value of dynamic MRI is lower than chemical shift MRI, in the atypical cases contrast enhancement patterns and time-to-peak and wash-in rates derived from SI-time curve of dynamic MRI give are contributory to the results of chemical shift MRI.     

3.0T MR对肾透明细胞癌和血管平滑肌脂肪瘤的鉴别诊断价值

目的 探讨结合MR平扫及增强参数、动态增强特征在肾透明细胞癌（clear cell renal cell carcinoma,CCRCC）及血管平滑肌脂肪瘤（renal angiomyolipoma,AML）鉴别诊断中的价值.方法 回顾性分析行3.0T MR平扫及增强扫描并经手术病理证实的肾透明细胞癌17例和血管平滑肌脂肪瘤12例,对压脂T2 WI（T2 WI-FS）信号、正反相位T1WI信号、强化程度进行定量测量.绘制ROC曲线,根据敏感性、特异性、Youden指数确定肿瘤与肾实质T2 WI信号强度（signal intensity,SI）比值阈值、正反相位信号强度比值百分比（SII）阈值、增强动脉-延迟期信号强度比值阈值.根据动态强化特征,绘制动态强化时间-信号曲线.结果 CCRCC的T2 WI SI比值、动脉-延迟期信号强度比值均大于AML,AML的SII大于CCRCC.CCRCC增强动脉期信号强度大于延迟期信号强度,而AML增强动脉期信号强度与延迟期信号强度相近.动态强化曲线显示为两型,一为流出型,其中CCRCC 16例,AML6例;二为平台型,其中CCRCC 1例,AML 2例.结论 在本研究中,CCRCC、AML T2 WI SI比值、SII、动脉-延迟信号强度比值有显著差异,动态增强扫描强化曲线各有不同.根据T2WI SI比值、SII、动脉-延迟信号强度比值可区分CCRCC和AML,其阈值分别为0.738、9.170％、1.224.     

MR evaluation of adrenal masses at 1.5 T

We retrospectively studied the value of MR imaging at 1.5 T to distinguish between nonadenomatous (n = 17) and adenomatous (n = 15) adrenal masses on the basis of (1) signal-intensity ratios on T1- and T2-weighted spin-echo images, (2) T2 relaxation times, and (3) T2 relaxation-time ratios. Univariate and then multivariate logistic regression were applied to these quantitative parameters to determine which of these best discriminated nonadenomas from adenomas, and whether or not more than one of these parameters improved the prediction. The adrenal mass/liver signal-intensity ratio on T2-weighted spin-echo images could not be used to differentiate nonadenomas from adenomas. Adrenal mass/fat signal-intensity ratios on T2-weighted spin-echo images, adrenal/liver T2 relaxation-time ratios, and adrenal mass T2 relaxation times were best for distinguishing nonadenomas from adenomas. By using a T2 value of greater than 61 msec, the true-positive ratio/false-positive ratio of differentiating nonadenomas from adenomas was 100%/20%; at greater than 82 msec, it was 64%/0.06%. The adrenal mass/fat signal-intensity ratios on T2-weighted spin-echo images and the adrenal/liver T2 relaxation-time ratios showed similar inherent discriminatory capacity. Overlap remains despite the use of these parameters. On the basis of this preliminary information, we conclude that MR has merit for the characterization of adrenal masses at 1.5 T. T2 relaxation time of the adrenal mass shows the greatest promise for discriminating nonadenomas from adenomas.