Perfusion characteristics of parotid gland tumors evaluated by contrast-enhanced ultrasound

Purpose

Contrast enhanced ultrasound (CE-US) is a promising imaging modality for non-invasive analysis of parotid gland lesions because their vascularisation differs from normal gland tissue. This clinical study should further investigate CE-US as a diagnostic tool for parotid gland tumors.

Materials and methods

39 patients underwent CE-US measurements after intravenous application of a contrast agent (SonoVue, Bracco, Italy) before surgical tumor resection. Time–intensity curves gradients were calculated and parameters of intratumoral microcirculation were analysed. The vascularisation parameters were compared among the different tumor entities as defined per definitive histological diagnosis.

Results

Histological analyses revealed 17 pleomorphic adenoma, 15 cystadenolymphoma and 7 malignoma. A significant difference of area below intensity time curve (AUC) and mean transit time (MTT) was measured in the malignant lesions compared to benign tumors (p < 0.05). A significant difference of AUC and maximum of signal increase (ΔSI_max) for pleomorphic adenoma versus cystadenolymphoma was found (p < 0.05).

Conclusion

CE-US seems to be a quantitative and independent method for the assessment of malign and benign parotid gland tumors. Further studies and clinical experience will have to validate this method as a reliable diagnostic tool that facilitates preoperative planning.     

腮腺多形性腺瘤与沃辛瘤的CT特征

目的：探讨计算机体层成像（computed tomography,CT）对腮腺多形性腺瘤（pleomorphic adenoma,PA）与沃辛瘤（Warthin tumor,WT）的诊断与鉴别诊断价值。方法：回顾并分析经病理学检查确诊的25例PA与20例WT的临床及影像学资料。患者均行颌面部CT平扫及增强扫描。结果：25例PA患者中,男性9例（36.0%）,女性16例（64.0%）,平均年龄（44.1±13.6）岁,均为单发,病灶位于非后下象限者22个（88.0%）,增强均表现为渐进性强化,静脉期呈轻-中度强化。20例WT患者均为男性（100.0%）,平均年龄（58.0±9.2）岁,均有长期吸烟史;其中10例（50.0%）多发,共35个病灶,25个病灶（71.4%）位于腮腺后下象限,35个病灶（100.0%）动脉期呈中度或明显强化,静脉期强化程度减低,呈“快进快出”表现。结论：不同的临床及CT特征在腮腺WT与PA的鉴别诊断中具有较高价值,可以对绝大多数病灶作出明确诊断。     

腮腺Warthin瘤的多层螺旋CT表现

目的 探讨腮腺Warthin瘤的多层螺旋CT表现特点.方法 搜集手术及病理证实的腮腺Warthin瘤16例,分析其部位、数目、大小、形态、边界、密度、强化特征.结果 16例共见21个病灶,左侧9个、右侧12个;浅叶18个,后下象限16个;病灶呈圆形或类圆形,平均直径2.5 cm;囊变14个;边界清楚19个;动态增强扫描病变显示为对比剂“快进快出”13例,3例显示延迟强化,5例见微血管征;同侧腮腺炎性反应1例,同侧颈部淋巴结肿大1例.结论 密切结合腮腺Warthin瘤临床表现特点及在多层螺旋CT表现,可对该病做出正确的诊断.     

The role of apparent diffusion coefficient (ADC) value in the differentiation between the most common pediatric posterior fossa tumors

Background

Diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) map provide information on MRI about the cellularity of the tumor and have an important role in the pre-operative differentiation of different tumor types.

Aim

Is to evaluate the role of ADC value measurement in the differentiation between the most common pediatric posterior fossa tumors which include juvenile pilocytic astrocytoma, ependymoma and medulloblastoma.

Patients & methods

Thirty patients were retrospectively included in this study. They were referred from the Neurosurgery Department and all of them suspected to have posterior fossa SOL according to the contrast enhanced CT. All patients were subjected to conventional MRI followed by diffusion MR imaging and calculation of the ADC values.

Results

In JPA (group 1, n = 14), ADC values ranged between 2.4 and 1.3 × 10⁻³ mm²/s, ependymoma (group 2, n = 9), ADC values ranged between 1 and 1.3 × 10⁻³ mm²/s and medulloblastoma (group 3, n = 7), ADC values ranged between 0.5 and 0.9 × 10⁻³ mm²/s. Statistically significant difference in ADC value was detected between group1, group 2 and group 3, while no statistically significant difference was detected between group 1 and group 2.

Conclusion

The calculation of ADC value in the solid enhancing portion of a tumor is a simple and reliable technique for preoperative differentiation of the most common posterior fossa.     

腮腺腺淋巴瘤的CT诊断

目的探讨腮腺腺淋巴瘤的CT表现与相关临床特点,以提高其诊断准确性。方法回顾性分析经手术病理证实的10例腮腺腺淋巴瘤CT资料。10例中男性9例,女性1例,年龄均为50岁以上,其中8例有多年吸烟史。结果 6例为单侧多发,2例为双侧多发,2例为单发,均表现为腮腺浅叶或后下象限边界清晰实性占位,增强扫描动脉期实性成分大部分明显强化,较大病灶多伴有不均匀轻、中度强化区及无强化坏死腔,长径小于1cm的病灶均呈均匀强化,部分较大病变有分叶,较大病灶直径约3cm左右,术后随访未见复发或转移者。结论腮腺腺淋巴瘤好发于50岁以上、与吸烟有明确相关的男性,多发病灶伴局灶性坏死者多见,当肿块发生于腮腺浅叶或后下象限,尤其当病灶多发,增强后明显强化时应首先考虑本病。     

The efficacy of apparent diffusion coefficient value calculation in differentiation between malignant and benign thyroid nodules

PurposeTo evaluate the efficacy of apparent diffusion coefficient (ADC) calculation in differentiation between malignant and benign thyroid nodules.Methods and materialsA prospective study was conducted in 52 patients. Diffusion-weighted echoplanar imaging was performed and b factors were taken as 0 and 400 s/mm².ResultsThe mean ADC value for malignant thyroid nodules was 0.829±0.179×10^?3 mm²/s and that for benign thyroid nodules was 1.984±0.482×10^?3 mm²/s. The mean ADC value for malignant nodules was significantly lower than that for benign nodules (P=.0001).ConclusionADC value calculation is an effective method in differentiation of malignant thyroid nodules from benign ones.     

Robust estimation of the apparent diffusion coefficient (ADC) in heterogeneous solid tumors

The least‐squares algorithm is known to bias apparent diffusion coefficient (ADC) values estimated from magnitude MR data, although this effect is commonly assumed to be negligible. In this study the effect of this bias on tumor ADC estimates was evaluated in vivo and was shown to introduce a consistent and significant underestimation of ADC, relative to those given by a robust maximum likelihood approach (on average, a 23.4 ± 12% underestimation). Monte Carlo simulations revealed that the magnitude of the bias increased with ADC and decreasing signal‐to‐noise ratio (SNR). In vivo, this resulted in a much‐reduced ability to resolve necrotic regions from surrounding viable tumor tissue compared with a maximum likelihood approach. This has significant implications for the evaluation of diffusion MR data in vivo, in particular in heterogeneous tumor tissue, when evaluating bi‐ and multiexponential tumor diffusion models for the modeling of data acquired with larger b‐values (b > 1000 s/mm²) and for data with modest SNR. Use of a robust approach to modeling magnitude MR data from tumors is therefore recommended over the least‐squares approach when evaluating data from heterogeneous tumors. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.     

Minor salivary gland tumors in the oral cavity: diagnostic value of dynamic contrast-enhanced MRI

Objective

To evaluate the diagnostic value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for minor salivary gland tumors in the oral cavity.

Materials and methods

Thirty-two patients with minor salivary gland tumors were examined preoperatively using DCE-MRI. Their maximum contrast index (CImax), time of CImax (Tmax), Tpeak; i.e., the time that corresponded to the CImax × 0.90, and washout ratios (WR300 and WR600) were determined from contrast index (CI) curves. We compared these parameters between benign and malignant tumors and among the different histopathological types of minor salivary gland tumors. Then, we categorized the patients’ CI curves into four patterns (gradual increase, rapid increase with high washout ratio, rapid increase with low washout, and flat).

Results

Statistically significant differences in Tmax (P = 0.004) and Tpeak (P = 0.002) were observed between the benign and malignant tumors. Regarding each histopathological tumor type, significant differences in Tmax (P < 0.001), Tpeak (P < 0.001), and WR600 (P = 0.026) were observed between the pleomorphic adenomas and mucoepidermoid carcinomas. It was difficult to distinguish between benign and malignant tumors using our CI curve classification because that two-thirds of the cases were classified into the same type (gradual increase).

Conclusion

The DCE-MRI parameters of minor salivary gland tumors contributed little to their differential diagnosis compared with those for major salivary gland tumors. During the diagnosis of minor salivary gland tumors, Tmax is useful for distinguishing between benign and malignant tumors.     

Value of apparent diffusion coefficient calculation in the differential diagnosis of parotid gland tumors

Background: The differential diagnosis of parotid gland tumors is often difficult with conventional magnetic resonance imaging.

Purpose: To determine whether the calculation of the apparent diffusion coefficient (ADC) is valuable for making the differential diagnosis of parotid tumors.

Material and Methods: Thirty parotid masses in 28 patients and 24 healthy parotid glands in 12 controls were examined in this prospective study. Diffusion-weighted magnetic resonance imaging with echo-planar spin-echo sequences was used to evaluate each subject. The ADC of each tumor and each healthy parotid gland was calculated. Tumor diagnoses were confirmed by the results of histopathologic analysis.

Results: The following types of masses were identified: 11 Warthin tumors, nine pleomorphic adenomas, seven malignant tumors, one basal cell adenoma, and two benign cysts. The mean ADC value for the Warthin tumors was 0.97±0.16×10^-3 mm²/s, for the pleomorphic adenomas was 1.74±0.37×10^-3 mm²/s, for the malignant tumors was 1.04±0.35×10^-3 mm²/s, and for the normal parotid glands was 0.34±0.20×10^-3 mm²/s. The respective ADC value for the single basal cell adenoma was 1.40×10^-3 mm²/s. Statistically significant differences were identified between the subjects with pleomorphic adenoma and those with another type of parotid tumor, and between subjects with healthy parotid glands and those with a tumor.

Conclusion: Calculating the ADC appears to be useful in differentiating pleomorphic adenomas from other types of parotid gland tumors.     

表观扩散系数和MR动态增强对前列腺中央腺体疾病的价值

目的评估表观扩散系数(ADC)及MR动态增强(DCE-MRI)对前列腺中央腺体病变的诊断价值。方法对经病理证实的50例前列腺中央腺体疾病患者进行扩散加权扫描(DWI)和DCE-MRI扫描,其中16例为前列腺癌(PCa),34例为前列腺增生(BPH)。分析基质增生为主型BPH(sBPH)、腺体增生为主型BPH(gBPH)和PCa的ADC值差别特点及信号强度-时间(SI-T)曲线特征。结果 gBPH、sBPH和PCa的平均ADC值分别为(1.33±0.25)×10-3 mm2/s、(1.04±0.22)×10-3 mm2/s、(0.71±0.32)×10-3 mm2/s,两两比较各组间有统计学差异(P<0.05)。SI-T曲线参数:达峰时间(Tmax)从高到低依次为sBPH、gBPH及PCa(P<0.05),强化程度(SI%)从高到低依次为sBPH、PCa及gBPH(P<0.05),强化率(R)从高到低依次为PCa、gBPH及sBPH(P<0.05)。结论 MR动态增强及ADC对前列腺中央腺体的病变有重要的诊断价值。     

Comparison of the return-to-the-origin probability and the apparent diffusion coefficient of water as indicators of necrosis in RIF-1 tumors.

Two model-independent measures of diffusion, the apparent diffusion coefficient (ADC) and return-to-the-origin probability enhancement (R) were compared for their ability to detect tissue necrosis in RIF-1 murine tumors. Both reflect the degree of restriction experienced by the endogenous water molecules; however, the ADC is calculated from the initial linear slope of the diffusion attenuation curve, while R is calculated from data that includes the non-monoexponential part of the curve. In spectroscopic studies (n = 9), neither the ADC nor R showed a strong correlation with tumor volume. In imaging studies (n = 14), ADC, R, and T(2) were calculated on a pixel-by-pixel basis. There, the mean ADC and mean R for the entire imaging slice showed reasonable correlation with necrotic tumor fraction (r(2) = 0.679 and -0.665, respectively). The mean T(2) value yielded a poor correlation (r(2) = 0.436). Regions-of-interest were chosen from areas identified as either necrotic or viable and the resulting sets of ADC and R-values were subjected to discriminant analysis to determine the identification error rate. The error was greater for R than for the ADC (P < 0.001). Therefore, in this application, the use of the non-monoexponential part of the diffusion attenuation curve does not provide additional identification power.     

腮腺多形性腺瘤和腺淋巴瘤的MSCT灌注成像研究

目的:探讨腮腺多形性腺瘤和腺淋巴瘤的MSCT灌注成像特征,以提高两者的诊断及鉴别诊断水平。方法:19例腮腺肿瘤患者术前行常规MSCT平扫后立即进行灌注扫描,采集数据输入Philips EBW后处理工作站,使用Perfusion软件进行数据处理,通过动态分析模块获得肿瘤感兴趣区时间-密度曲线(TDC),计算肿瘤血容量(BV)、达峰时间(TTP)和强化峰值(PEI),并根据色阶分别获取相应的伪彩图。所有患者最终均经手术病理学明确诊断。结果:1手术病理:19例腮腺肿瘤中,多形性腺瘤6例,腺淋巴瘤12例(其中2例因图像伪影明显不计入研究),腮腺癌1例(排除研究)。2MSCT灌注TDC特征:9例腺淋巴瘤呈"快进快退"型,1例呈"快进缓降"型,6例多形性腺瘤均呈"缓慢上升"型。3腺淋巴瘤的BV和PEI值均高于多形性腺瘤,而TTP值低于多形性腺瘤(P均<0.05)。4受试者工作特征(ROC)曲线显示BV和PEI值在多形性腺瘤和腺淋巴瘤间具有统计学差异,曲线下面积分别为0.93和0.97,而TTP值在两者间不存在统计学差异。结论:MSCT灌注成像在腮腺多形性腺瘤和腺淋巴瘤的诊断及鉴别诊断中具有重要价值。     

腮腺肿瘤的CT及MRI诊断及鉴别诊断

目的：探讨腮腺肿瘤的CT及MRI表现,旨在提高对腮腺肿瘤的诊断水平。方法：回顾性分析经病理证实的90例腮腺肿瘤的CT及MRI的表现。结果：90例腮腺肿瘤中,良性肿瘤74例（82.2%）,恶性肿瘤16例（17.8%）。在CT/MRI上,良性肿瘤大部分表现为位于腮腺浅叶的圆形、椭圆形软组织肿块,边缘光整,密度/信号均匀;而恶性肿瘤,大部分位于腮腺深叶或跨叶,表现为不规则形软组织肿块,边缘不清,密度/信号不均匀,侵犯周围组织并伴淋巴结转移。结论：CT和MRI检查均能对腮腺肿瘤进行有效定位,并对诊断及鉴别诊断具有一定价值。     

表观扩散系数值鉴别良恶性骨肿瘤及肿瘤样病变的价值

目的 探讨MR DWI的ADC值鉴别良、恶性骨肿瘤及肿瘤样病变的价值.方法 对18例良性骨肿瘤及肿瘤样病变和26例恶性骨肿瘤行DWI.采用单激发EPI序列,3个扩散敏感梯度,b值分别为0.500、1000 s/nun2.在ADC图上测量每个病变的最低、最高和整体ADC值.结果 良性骨肿瘤及肿瘤样病变的最低ADC值[(1.28±0.49)×10-3mm2/s]高于恶性骨肿瘤[(0.92±0.35)×10-3mm2/s,t=2.839,P<0.01],整体ADC值[(1.62±0.51)×10-3mm2/s]也高于恶性骨肿瘤[(1.21±0.36)×10-3mm2mm/s,t=3.092,P<0.01],但两者都有很大重叠.良性骨肿瘤及肿瘤样病变的最高ADC值[(2.02±0.55)×10-3mm2/s]与恶性骨肿瘤的最高ADC值[(1.71±0.65)×10-3mm2/s]差异无统计学意义(t:1.669,P＞0.05).去掉以囊腔为主的骨囊肿及动脉瘤样骨囊肿病例,则良性骨肿瘤及肿瘤样病变的最低、最高和整体ADC值分别为(1.11±0.31)×10-3mm2/s、(1.88±0.49)×10-3mm2/s和(1.45±0.35)×10-3mm2/s,与恶性骨肿瘤比较差异无统计学意义(t值分别为1.728、0.964、2.012,P值均>0.05).结论 ADC值不能鉴别良、恶性骨肿瘤及肿瘤样病变.     

腮腺基底细胞腺瘤的CT、US诊断价值

目的分析腮腺基底细胞瘤的CT、Us影像表现,探讨CT、US检查对腮腺基底细胞瘤的诊断价值。方法回顾性分析18例腮腺基底细胞瘤的CT、Us表现及临床相关资料,所有病例均经手术病理证实。18例均行CT及us检查,CT检查均行平扫加增强扫描,其中ll例行延迟1～1．5min扫描。结果18例中,男性3例,女性15例,男女比例1：5;中位年龄52岁,共发现基底细胞瘤21个。单侧单发15例,其中1例合并对侧腺淋巴瘤;单侧多发2例;双侧多发1例。15个病灶发生于腮腺浅叶。加个病灶跨叶分布。6个病灶发生于左叶,15个病灶发生于右叶。21个病灶外形均规整,边界清,包膜完整;11个病灶发生囊变,其中6例囊变率达80％以上;11个病灶囊变区边缘可见壁结节,7个病灶囊变边缘可见花环征。CT增强扫描16个病灶实性部分明显强化,4个病变中度强化,1个病变轻度强化。9个病灶延迟强化减退,3个病灶延迟强化。超声发现11例混合型病变,回声不均匀,内可见大小不一的液性暗区,15个病灶CDFI显示内部和／或周边血流信号丰富,呈短条状,4个病灶可见散在点状血流信号,4个病灶未见明显血流信号;9个病灶回声均匀,12例回声不均匀,其中2例病灶后方回声增强。结论腮腺基底细胞瘤的CT、US影像表现具有一定特征,结合患者的性别、年龄等,有助于鉴别诊断。     

Value of combined real time sonoelastography and apparent diffusion coefficient value measurement in differentiation of enlarged neck lymph nodes

Purpose

To evaluate the role of real-time sonoelastography (UE) and apparent diffusion coefficient (ADC) value measurement in differentiating benign versus malignant enlarged neck lymph nodes.

Materials and methods

This study included 26 patients presented with 32 enlarged neck lymph nodes (LNs), underwent real-time UE and diffusion weighted MRI (DWI). ADC maps are generated from DWI and ADC values were calculated. Both UE and ADC findings were compared with histopathological results.

Results

The LNs were 12 benign lymphadenopathy (37.5%, seen in 10 patients), 10 metastatic (31.25% seen in 8 patients) and 10 lymphoma (31.25%, seen in 8 patients) including 4 LNs with Hodgkin’s lymphoma (HL, seen in 3 patients) and 6 LNs with non Hodgkin’s lymphoma (NHL, seen in 5 patients). On UE 10 of the 12 benign LNs had pattern of 1–2 (83.3%) and 18 of 20 neoplastic LNs (90%) had pattern of 4–5. The mean ADC values of the benign, metastases and lymphoma groups were 1.52 ± 0.37, 0.90 ± 0.15 and 0.72 ± 0.12 × 10⁻³ (mm²/s), respectively.

Conclusion

Combined real-time UE and ADC value measurement are non invasive techniques useful for differentiation of enlarged neck lymph. The combination potentially could reduce unnecessary biopsy especially for elasticity pattern 1–2.     

Diagnostic utility of diffusion‐weighted MR imaging and apparent diffusion coefficient value for the diagnosis of adrenal tumors

Purpose

To determine the utility of diffusion‐weighted MR imaging (DWI) for the diagnosis of adrenal tumors.

Materials and Methods

Forty‐two patients (24 men and 18 women; age, 61.5 ± 12.7 years old; range, 34–86 years) with 43 adrenal tumors (11 functioning cortical adenomas, 20 nonfunctioning cortical adenomas, 7 metastatic tumors, and 5 pheochromocytomas) were retrospectively investigated. DWIs were obtained by single‐shot spin‐echo type echo‐planar imaging sequence (1.5 Tesla [T]; TR = 8000 ms, TE = 72, b‐factor = 0 and 1000 s/mm²), and apparent diffusion coefficient (ADC) value was calculated. Chemical shift images were obtained by gradient echo sequence (TR = 161, TE = 2.38 [out‐of‐phase, OP] and 4.76 [in‐phase, IP], FA = 60), and the signal intensity index (SII; [IP‐OP]/IP *100%) was calculated.

Results

There was no difference in ADC values between adenomas (1.09 ± 0.29*10^?3 mm²/s; range, 0.52–1.64) and metastatic tumors (0.85 ± 0.26*10^?3; 0.51–1.23; p = 0.14). Pheochromocytomas showed the higher mean ADC value (1.59 ± 0.34*10^?3; 1.04–1.96) compared with those of adenomas or metastatic tumors (P < 0.05 and P < 0.005, respectively). The mean SII of adenomas (62.1 ± 17.9%; 14.5–88.4) was significantly higher than those of pheochromocytomas (4.0 ± 10.0%; ?19.6–3.3; P < 0.005) or metastatic tumors (?1.5 ± 11.7%; ?18.3–8.2; P < 0.01). There was no correlation between ADC values and SII.

Conclusion

Although pheochromocytomas showed higher ADC values, we did not find that ADC value had diagnostic utility for differentiating adenomas and metastatic tumors. J. Magn. Reson. Imaging 2009;29:112–117. © 2008 Wiley‐Liss, Inc.

     

CT灌注成像在腮腺肿瘤鉴别诊断中的临床价值

目的探讨多层螺旋CT灌注成像技术定量评价腮腺良、恶性肿瘤的血液动力学特点及其对腮腺良恶性肿瘤的鉴别诊断价值。方法53例患者共57个病变，其中良性肿瘤35例，恶性肿瘤18例，全部经术后病理证实。术前行CT灌注检查。采用Philips perfusion功能软件包获取组织的时间密度曲线（time density calve，TDC）及CT灌注参数，包括灌注量、增强峰值（PH）、达峰时间（TTP）、血容量（BV）、平均通过时间（MTT）。采用Wilcoxon符号秩和检验进行统计学处理。结果腮腺良性肿瘤的CT灌注参数的中位数及四分位间距[25％CI 75％（Q1，Q2）]分别为：灌注量73．5（18．7，113．3）ml·100g^-1·min^-1、PH 34．5（17．7，53．1）HU、TTP 20．0（13．6，34．4）S、BV 38．5（29．1，63．3）ml·100g^-1、MTT 7．6（4．5，28．7）s。腮腺恶性肿瘤的CT灌注参数分别为：灌注量135．9（101．4，195．2）ml·100g^-1·min^-1，PH 49．1（32．7，59．4）HU，TTP 12．9（11．3，14．6）s，BV 67．5（52．4，109．5）ml·100g^-1，MTT 6．0（5．1，7．6）s。统计结果显示，CT灌注参数BF、BV、TTP的中位数及四分位间距在腮腺良恶性肿瘤之间差异具有统计学意义（P值均〈0．05），而PH、及MTT之间差异无统计学意义（P〉0．05）；腺淋巴瘤、其他良性肿瘤、恶性肿瘤的TDC的差异也有统计学意义（P值均〈0．05）。结论CT灌注扫描技术对腮腺良恶性肿瘤的鉴别诊断具有一定价值。