Prostate cancer: added value of subtraction dynamic imaging in 3T magnetic resonance imaging with a phased-array body coil

Purpose

To determine the added value of dynamic subtraction magnetic resonance (MR) imaging for the localization of prostate cancer.

Materials and Methods

We examined 21 consecutive patients who underwent MR imaging in 3T unit with a phased-array body coil and then had radical prostatectomy. After T2-weighted fast spin-echo imaging, we performed a contrast-enhanced dynamic 3D gradient-echo imaging consisting of pre-contrast, 2 successive early-phased (first imaging was started just after the appearance of contrast material in the aortic bifurcation followed by second imaging 35 seconds after the initiation of first imaging) and one 5-minute delayed post-contrast series. Subtraction of pre-contrast images from corresponding post-contrast images of each phase was performed on the console.

Results

On ROC analysis, the overall accuracy (A_z value) of dynamic imaging combined with subtraction imaging was higher than T2-weighted imaging (p = 0.001) or conventional dynamic imaging alone (p = 0.074) for localization of cancer foci regardless of their zonal locations. Among pathologically verified 81 lesions, the mean volume of detected lesions with the subtraction images (n = 49, 0.69 cm³) was smaller than with T2-weighted images (n = 14, 1.05 cm³) or conventional dynamic images (n = 43, 0.71 cm³).

Conclusion

For localization of small prostate cancer, additional subtraction for the dynamic imaging could be superior to both T2-weighted imaging and un-subtracted dynamic imaging.     

Focal lesions in cirrhotic liver: comparing MR imaging during arterial portography with Gd-enhanced dynamic MR imaging

The purpose of this study was to document the additional value of MR imaging during arterial portography (MRAP) in patients examined with intravenous contrast-enhanced dynamic MR imaging for the assessment of focal lesions in patients with cirrhosis or chronic viral hepatitis. The MR images of 24 patients with 39 hepatocellular carcinomas and 18 benign hepatocellular nodules examined with dynamic MR imaging and MRAP within a 14-day interval were retrospectively reviewed. For 39 hepatocellular carcinomas, MRAP revealed 37 perfusion defects (95%), while dynamic MR imaging demonstrated 35 occurrences of nodular contrast-enhancement (90%) on arterial dominant phases. Among the 11 benign nodules misinterpreted as hepatocellular carcinoma due to their high signal intensities on arterial-dominant phases of dynamic MR imaging, eight (73%) showed intratumoral portal venous perfusion on MRAP and were regarded as benign nodules. As a result of its high sensitivity and its potential ability to enable differentiation of benign and malignant hepatocellular nodules, MRAP can be added to dynamic MR imaging for planning future management in patients with equivocal hepatocellular nodules in the cirrhotic liver.     

Hyperspectral imaging of atherosclerotic plaques in vitro

Vulnerable plaques constitute a risk for serious heart problems, and are difficult to identify using existing methods. Hyperspectral imaging combines spectral- and spatial information, providing new possibilities for precise optical characterization of atherosclerotic lesions. Hyperspectral data were collected from excised aorta samples (n = 11) using both white-light and ultraviolet illumination. Single lesions (n = 42) were chosen for further investigation, and classified according to histological findings. The corresponding hyperspectral images were characterized using statistical image analysis tools (minimum noise fraction, K-means clustering, principal component analysis) and evaluation of reflectance/fluorescence spectra. Image analysis combined with histology revealed the complexity and heterogeneity of aortic plaques. Plaque features such as lipids and calcifications could be identified from the hyperspectral images. Most of the advanced lesions had a central region surrounded by an outer rim or shoulder-region of the plaque, which is considered a weak spot in vulnerable lesions. These features could be identified in both the white-light and fluorescence data. Hyperspectral imaging was shown to be a promising tool for detection and characterization of advanced atherosclerotic plaques in vitro. Hyperspectral imaging provides more diagnostic information about the heterogeneity of the lesions than conventional single point spectroscopic measurements.     

应用MRI技术对肝脏局灶结节性增生的诊断

目的 评估磁共振成像（magnetic resonance imaging,MRI）技术对肝脏局灶结节性增生（focal nodular hyperplasia,FNH）的诊断价值.方法 回顾性分析齐齐哈尔市第一医院2008年1月至2010年4月经手术切除或穿刺活检病理证实的10例26灶FNH 磁共振平扫、动态增强表现,由3名有经验的医师做MR表现诊断.结果 对于10例中的26个病灶,平扫T1WI上23个病灶为稍低或等信号、3个病灶为稍高信号;T2WI上23个病灶呈稍高信号、1个病灶等信号,2个病灶呈稍低信号.在动脉期5个病灶明显不均匀增强、19个病灶显著均匀增强,门静脉期和延迟期13个病灶呈稍高信号,11个病灶呈等/稍低信号,2个病灶无强化.11个病灶检出瘢痕,T1WI呈低信号,T2WI呈低或高信号,动脉期无增强、门静脉期或延迟期增强.8例诊断正确,1例诊断为良性病变（定性困难）,1例误诊为恶性肿瘤.结论 MRI能显示单发或多发FNH的特征性改变,并在术前正确诊断大部分FNH.     

Magnetic resonance imaging characteristics of deep endometriosis

The aim of this study was to describe magnetic resonance (MR) imaging findings in histopathologically proven deep endometriosis infiltrating the uterosacral ligaments, the pouch of Douglas, the rectum or the bladder. Twenty patients presenting with a clinical suspicion of deep endometriosis underwent preoperative MR imaging. Sagittal and axial fast T2- and axial T1-weighted spin echo MR sequences were performed. Four patients had post-contrast images. MR results, including morphology and signal intensity of each lesion, were compared to intraoperative gross appearance and histopathology. Histopathology diagnosed 24 lesions of deep endometriosis in the uterosacral ligaments (n = 12), the pouch of Douglas (n = 2), the rectum (n = 3), the bladder (n = 7). Uterosacral ligaments with deep endometriosis were statistically different from normal uterosacral ligaments for proximal nodularity (P = 0.001). There was no difference in signal intensity between normal and abnormal uterosacral ligaments. Contrast-enhanced SE images in four patients with detrusor invasion showed an interruption of the hypointense detrusor by the enhancing bladder endometriosis. Rectal endometriosis was missed in two of three patients and showed non-specific rectal wall thickening in one patient. It is concluded that MR imaging can diagnose deep endometriosis of uterosacral ligaments, the bladder and the pouch of Douglas, but lacks sensitivity in detecting rectal endometriosis without rectal distension.     

Linear motion correction in three dimensions applied to dynamic gadolinium enhanced breast imaging.

Quantitative analysis of dynamic gadolinium-DTPA (diethylenetriamine pentaacetic acid) enhanced magnetic resonance imaging (MRI) is emerging as a highly sensitive tool for detecting malignant breast tissue. Three-dimensional rapid imaging techniques, such as keyhole MRI, yield high temporal sampling rates to accurately track contrast enhancement and washout in lesions over the course of multiple volume acquisitions. Patient motion during the dynamic acquisitions is a limiting factor that degrades the image quality, particularly of subsequent subtraction images used to identify and quantitatively evaluate regions suggestive of malignancy. Keyhole imaging is particularly sensitive to motion since datasets acquired over an extended period are combined in k-space. In this study, motion is modeled as set of translations in each of the three orthogonal dimensions. The specific objective of the study is to develop and implement an algorithm to correct the consequent phase shifts in k-space data prior to offline keyhole reconstruction three-dimensional (3D) volume breast MR acquisitions.     

MR imaging of renal cell carcinoma: associations among signal intensity, tumor enhancement, and pathologic findings

The purpose of this study was to compare the MR characteristics of renal cell carcinomas against histologic findings and to assess the correlations among signal intensity, tumor enhancement, and pathologic findings. Fifty-four patients (56 lesions) were examined by MR imaging and then underwent partial or radical nephrectomy. The pathologic diagnosis of all lesions was renal cell carcinoma. All MR examinations were performed as dynamic studies using the same 1.5-T scanner. MR characteristics were compared against pathologic findings after resection, and the correlations among signal intensity, tumor enhancement, and pathologic findings were then assessed. A significant correlation was observed between tumor grade and tumor enhancement, with G3 lesions tending to show little enhancement. Regardless of the histologic classification, G3 tumors were found to contain highly heterotypic cancer cells and very few vessels by histopathologic examination. No significant correlations were noted between the other MR characteristics and pathologic findings. Renal cell carcinomas showing little enhancement tend to be highly malignant lesions based on the pathologic findings. Special consideration is required for these tumors with regard to the selection of surgical intervention and follow-up observation.     

Early homogeneously enhancing hemangioma versus hepatocellular carcinoma: differentiation using quantitative analysis of multiphasic dynamic magnetic resonance imaging.

The aim of this study was to determine the usefulness of quantitative analysis of multiphasic dynamic contrast-enhanced magnetic resonance (MR) imaging in differentiating early homogeneously enhancing hemangiomas from hepatocellular carcinomas (HCCs). Four-phased dynamic MR imaging at 10 sec (first phase of dynamic contrast-enhanced imaging, P1), 35 sec (second phase, P2), 60 sec (third phase, P3) and 300 sec (delay phase, P4) immediately after intravenous administration of 0.1 mmol/kg Gadolinium-DTPA was obtained with 1.5-T unit with breath-hold multisection FLASH (fast low angle-shot) sequence (TR/TE, 113-130 msec/4.1 msec; flip angle, 80 degrees). Thirty-three HCCs and 18 hemangiomas, homogeneously enhanced on P1, were included in the study. The images were evaluated quantitatively (SNR, signal-to-noise ratio; and CNR, contrast- to- noise ratio of lesions). Quantitatively, mean CNR was higher for hemangiomas than for HCCs on all phases, and the difference in CNRs between hemangioma and HCCs was statistically significant on P3 and P4 (p < 0.0001). When the cutoff for CNR was set at a value of 7.00 on P3 and 1.00 on P4, sensitivity, specificity and accuracy were 94.4%, 93.9%, and 94.1% on P3, and 94.4%, 81.8%, and 86.3% on P4, respectively. There was no statistically significant difference in SNRs between HCC and hemangioma. The differential diagnosis between early, homogeneously enhancing hemangiomas and HCCs was more confidently made with CNRs of lesions on P3 and P4 in dynamic contrast-enhanced MR imaging.     

Sequential changes of traumatic vertebral compression fracture on MR imaging.

The purpose of this study was to evaluate the sequential signal intensity changes in post-traumatic vertebral compression fractures of varying ages. Sixty-six patients with 115 post-traumatic vertebral compression fractures underwent MR imaging. The ages of fractures at the time of MR images ranged from 1 day to 6 years. Sequential follow-up MR imagings were obtained in 4 patients for 2 years after initial MR examination. The fracture sites in all 52 fractures with traumatic events less than 3 months prior were hypointense on T1-weighted images and hyperintense on T2-weighted images (type I). A type I fracture could be subdivided into 3 patterns depending on its morphologic appearance: diffuse (type Ia); patchy (type Ib); and bandlike (type Ic). In 12 fractures of 3 to 5 months after trauma, six showed focal hypointensity (type II) in all pulse sequences, and six showed isointensity (type IV). Four of 51 fractures with trauma over 5 months showed focal hyperintensity on T1-weighted images and isointensity on T2-weighted images (type III); and the remaining 47 fractures showed isointensity on all sequences (type IV). In conclusion, MR imaging is useful in predicting the age of known traumatic compression fractures, so familiarity with these sequential MR findings would be helpful in distinguishing benign from malignant fractures.     

Evaluation of edge effect due to phase contrast imaging for mammography

It is well-known that the edge effect produced by phase contrast imaging results in the edge enhancement of x-ray images and thereby sharpens those images. It has recently been reported that phase contrast imaging using practical x-ray tubes with small focal spots has improved image sharpness as observed in the phase contrast imaging with x-ray from synchrotron radiation or micro-focus x-ray tubes. In this study, we conducted the phase contrast imaging of a plastic fiber and plant seeds using a customized mammography equipment with a 0.1 mm focal spot, and the improvement of image sharpness was evaluated in terms of spatial frequency response of the images. We observed that the image contrast of the plastic fiber was increased by edge enhancement, and, as predicted elsewhere, spectral analysis revealed that as the spatial frequencies of the x-ray images increased, so did the sharpness gained through phase contrast imaging. Thus, phase contrast imaging using a practical molybdenum anode tube with a 0.1 mm-focal spot would benefit mammography, in which the morphological detectability of small species such as microcalcifications is of great concern. And detectability of tumor-surrounded glandular tissues in dense breast would be also improved by the phase contrast imaging.     

Value of magnetic resonance imaging in predicting efficacy of GnRH analogue treatment for uterine leiomyoma

BACKGROUND: Estimating pharmacological efficacy is important when selecting conservative treatment of uterine leiomyoma. Hence, the ability of magnetic resonance (MR) imaging to predict gonadotrophin-releasing hormone (GnRH) analogue efficacy was investigated. METHODS: A total of 85 lesions was studied in 40 patients who were clinically diagnosed as having uterine leiomyoma and treated with GnRH analogue for 24 weeks. To evaluate changes in lesion size, T2-weighted and gadopentetate-dimeglumine (Gd-DTPA)-enhanced, T1-weighted MR images were obtained within 2 weeks before, and immediately after termination of, GnRH analogue treatment. RESULTS: An average 46.3% size reduction was observed in 45 lesions (52.9%); these were seen as low signal intensity on T2-weighted images and enhanced by Gd-DTPA. Also, an average 44.7% size reduction was observed in lesions enhanced by Gd-DTPA, irrespective of signal intensity findings on T2-weighted images. The average size reduction of unenhanced lesions was only 17.8%, and significantly different from enhanced lesions (P < 0.001). The prediction of efficacy was difficult in those lesions not enhanced. CONCLUSIONS: It is considered that evaluation of MR signal intensities, and the presence or absence of Gd-DTPA enhancement, would predict treatment efficacy before GnRH analogue administration.     

椎间隙感染的MRI诊断

目的：分析椎间隙感染的MRI影像特征，评价椎间隙感染的MRI诊断价值。方法：对15例经临床或手术病理证实的椎间隙感染患者行脊柱MRI检查，扫描序列为矢状面FrFsE-T1WI、FrFSE-T2WI、脂肪抑制T2WI，横断面FrFSE-T2WI，其中5例行Gd-DTPA增强对比扫描。结果：15例患者共发现17个椎间隙感染，其中15个发生于腰椎间隙。椎间隙狭窄(13个)，病变椎间盘呈不同程度破坏、碎裂，呈长T1(17个)长T2(15个)信号，T2上椎间盘髓核内正常裂隙状低信号消失(13个)，上下相邻椎体受累破坏(15个)，椎旁软组织肿胀(8个)。5例行Gd-DT-PA增强对比扫描可见病变椎间盘、相邻椎体及椎旁软组织异常强化。结论：MRI对诊断椎间隙感染具有很高的敏感性和准确性，应作为首选的影像学检查方法：     

Optimising the scan delay for arterial phase imaging of the liver using the bolus tracking technique

Objective:

To optimize the delay time before the initiation of arterial phase scan in the detection of focal liver lesions in contrast enhanced 5 phase liver CT using the bolus tracking technique.

Patients and Methods:

Delay - the interval between threshold enhancement of 100 hounsfield unit (HU) in the abdominal aorta and commencement of the first arterial phase scan. Using a 16 slice CT scanner, a plain CT of the liver was done followed by an intravenous bolus of 120 ml nonionic iodinated contrast media (370 mg I/ml) at the rate of 4 mL/s. The second phase scan started immediately after the first phase scan. The portal venous and delay phases were obtained at a fixed delay of 60 s and 90 s from the beginning of contrast injection. Contrast enhancement index (CEI) and subjective visual conspicuity scores for each lesion were compared among the three groups.

Results:

84 lesions (11 hepatocellular carcinomas, 17 hemangiomas, 39 other hypervascular lesions and 45 cysts) were evaluated. CEI for hepatocellular carcinomas appears to be higher during the first arterial phase in the 6 seconds delay group. No significant difference in CEI and mean conspicuity scores among the three groups for hemangioma, other hypervascular lesions and cysts.

Conclusion:

The conspicuity of hepatocellular carcinomas appeared better during the early arterial phase using a bolus tracking technique with a scan delay of 6 seconds from the 100 HU threshold in the abdominal aorta.     

Diagnostic Value of 3D Fast Low-Angle Shot Dynamic MRI of Breast Papillomas

Purpose

To evaluate the value of breast MRI in analysis of papillomas of the breast.

Materials and Methods

From 1996 to 2004, 94 patients underwent surgery due to papillomas of the breast. Among them, 21 patients underwent 3D fast low angle shot (FLASH) dynamic breast MRI. Eight masses were palpable and 11 of 21 patients had nipple discharge. Two radiologists indifferently analyzed the location, size of the lesions and shape, margin of the masses, multiplicity and ductal relation. The MRI findings were categorized according to breast imaging reporting and data system (BI-RADS) lexicon. The amount and pattern of enhancement and associated findings were also evaluated according to BI-RADS. We then compared the MRI findings with galactography, mammography and breast ultrasonography (US) and examined histopathologic correlation.

Results

On breast MRI, the lesion size was 0.4-1.59 cm, and 18 patients showed subareolar location. On 4.25 cm (mean 1.54) dynamic enhanced images, imaging findings showed mass (n = 10), intracystic mass (n = 3), focus (n = 5), ductal enhancement (n = 2), and segmental enhancement (n = 1). In cases of the masses, the shapes of the masses were round (n = 4), lobulated (n = 3), and irregular (n = 6), and margins were circumscribed (n = 6), microlobulated (n = 5), and indistinct (n = 2). The enhancement patterns were homogeneous enhancement (n = 7), heterogeneous (n = 3) or rim enhancement (n = 3).

Conclusion

The contrast enhanced dynamic breast MRI was highly sensitive for diagnosis of breast papillomas. MRI could play a key role in the pre-operative work-up for multiple papillomas and papillomatosis.     

内耳钆造影MRI前庭导水管显影的观察及临床意义

目的 探讨经鼓室内耳钆造影MRI前庭导水管显影率及其临床意义。方法 回顾性分析。纳入2010年2月-2018年1月福建医科大学附属第一医院影像科691例经鼓膜穿刺注射行内耳钆造影MRI的患者造影前后MRI及临床资料,其中男300例、女391例,年龄9~82岁。691例中,531例双侧、160例单侧(共1 222侧)行内耳钆造影。临床表现为眩晕483例、突发性耳聋125例、头晕42例、耳鸣39例、无症状2例,按症状有无进行分组观察。观察患者MRI图像,与造影前相比,造影后前庭导水管区信号升高即判定有显影,否则为无显影;另外,采用目测评分法评价内耳膜迷路是否积水。采用χ²检验分析眩晕组与非眩晕组、突聋组与非突聋组、耳鸣组与非耳鸣组之间前庭导水管显影发生率是否有差异,应用列联相关系数分析前庭导水管显影与膜迷路积水之间的关系。结果 全组691例1 222耳中,26.8%(327/1 222耳)可见膜迷路积水,7.4%(90/1 222耳)可见前庭导水管显影。眩晕组6.0%(56/938耳)可见前庭导水管显影,非眩晕组12.0%(34/284耳)可见显影,差异有统计学意义(χ²=11.509, P＜0.01);突聋组10.2%(19/186耳)可见前庭导水管显影,非突聋组6.9%(71/1 036耳)可见显影,差异无统计学意义(χ²=2.612, P＞0.05);耳鸣组4.0%(6/149耳)可见前庭导水管显影,非耳鸣组7.9%(85/1 073耳)可见显影,差异无统计学意义(χ²=2.880, P＞0.05)。眩晕组30.1%(282/938耳)可见膜迷路积水,非眩晕组15.8%(45/284耳)可见膜迷路积水,差异有统计学意义(χ²=22.488, P＜0.01)。出现膜迷路积水的耳中3.1%(10/327耳)可见前庭导水管显影,无膜迷路积水的耳中8.9%(80/895耳)可见显影,差异有统计学意义(χ²=12.139, P＜0.01);前庭导水管显影与膜迷路积水之间存在负相关关系(r=-0.099, P＜0.01)。结论 鼓室法内耳钆造影MRI图像上,钆对比剂可以进入前庭导水管,显影率约7.4%;骨性前庭导水管内存在外淋巴间隙;内耳钆造影MRI图像上前庭导水管不显影患者存在膜迷路积水的可能性更大,提示有关前庭导水管问题可能是梅尼埃病或眩晕发病机制的重要环节。     

不典型肝癌的多排螺旋CT三期增强扫描影像浅析

目的:通过多排螺旋CT(Multi-slicespiralCT,MSCT)三期增强扫描,分析不典型肝癌影像特征,评估诊断价值。方法:选取2012年5月至2020年7月间52例原发性肝癌患者进行回顾性分析研究,所有患者均接受MSCT三期动态增强扫描,对比分析患者肝脏平扫、增强扫描动脉期、门脉期及延迟期扫描图像特征与病理类型,找出其中不典型肝癌MSCT三期增强表现并进行统计学分析。结果:多数病例影像表现呈典型“速升-速降”型,部分病例影像为非典型表现:动脉期轻度强化9例,无强化1例,边缘结节样及环形强化3例;门脉期高密度5例,等密度7例;延迟期稍高密度4例,等密度3例;中心出现“星芒样”无强化区1例。肿瘤血供、细胞成分和自身的分化程度以及肝脏基础病变等与不典型肝癌MSCT三期动态增强扫描图像特征相关。结论:大多数原发性肝细胞癌在肝脏增强的三期动态扫描中呈典型“速升-速降”型表现,不典型肝癌MSCT多期增强扫描影像表现多样,缺乏特征性,鉴别难度大,应适时运用CT同层灌注扫描成像、MRI多序列成像、DWI(弥散加权成像)、ADC值(表观弥散系数)、CT碘油造影等检查手段并结合临床实验室检查,必要时活检,提高诊断准确率。     

Evaluation of combined late gadolinium-enhancement and functional cardiac magnetic resonance imaging using spiral real-time acquisition

The purpose of the current study was to implement and validate joint real-time acquisition of functional and late gadolinium-enhancement (LGE) cardiac magnetic resonance (MR) images during free breathing. Inversion recovery cardiac real-time images with a temporal resolution of 50 ms were acquired using a spiral trajectory (IR-CRISPI) with a pre-emphasis based on the gradient system transfer function during free breathing. Functional and LGE cardiac MR images were reconstructed using a low-rank plus sparse model. Late gadolinium-enhancement appearance, image quality, and functional parameters of IR-CRISPI were compared with clinical standard balanced steady-state free precession breath-hold techniques in 10 patients. The acquisition of IR-CRISPI in free breathing of the entire left ventricle took 97 s on average. Bland–Altman analysis and Wilcoxon tests showed a higher artifact level for the breath-hold technique (p = 0.003), especially for arrhythmic patients or patients with dyspnea, but an increased noise level for IR-CRISPI of the LGE images (p = 0.01). The estimated transmural extent of the enhancement differed by not more than 25% and did not show a significant bias between the techniques (p = 0.50). The ascertained functional parameters were similar for the breath-hold technique and IR-CRISPI, that is, with a minor, nonsignificant (p = 0.16) mean difference of the ejection fraction of 2.3% and a 95% confidence interval from −4.8% to 9.4%. IR-CRISPI enables joint functional and LGE imaging in free breathing with good image quality but distinctly shorter scan times in comparison with breath-hold techniques.     

Evaluation of ectopic pregnancy by magnetic resonance imaging.

Patients (n = 37) suspected of ectopic pregnancy were prospectively evaluated with magnetic resonance (MR) imaging to assess the capability of MR imaging in the diagnosis of ectopic pregnancy. Five levels of confidence were defined: diagnostic, suspicious, equivocal, questionable, and negative. Tubal wall enhancement and presence of tubal haematoma or gestational sac-like structure were considered diagnostic findings. There were 21 diagnostic, two suspicious, eight equivocal, and six negative findings. MR findings were compared with the surgical findings in 18 patients. Surgical confirmation was obtained in 12 diagnostic, two suspicious, and four equivocal studies. Using the MR diagnostic criteria for tubal pregnancy, MR had 12 true positive, three true negative, three false negative, and no false positive results for the diagnosis of tubal pregnancy. Retrospective analysis of the signal intensity of haematoma and ascites was performed for these 18 surgically confirmed cases. The predominant signal intensity of tubal haematoma was an intermediate signal on T1-weighted image (WI) and a low signal on T2WI. Ascites showed signal intensity higher than that of urine on T1WI in 100% of 13 cases. In conclusion, MR imaging with use of intravenous contrast material allows a specific diagnosis of tubal pregnancy, recognizing tubal wall enhancement and fresh tubal haematoma.     

MR imaging evaluation of postmenopausal adnexal masses: correlation with final pathologic diagnosis

OBJECTIVE: Adoption of transvaginal ultrasound in usual clinical settings allowed us to find asymptomatic adnexal masses more frequently in postmenopausal women. These masses were traditionally considered as the indication of surgical excision to determine histological diagnosis. Recently, if the appearance of that is simple cyst, conservative management may be acceptable because ultrasound benign diagnosis is proved to be reasonably reliable. We investigate here the reliability of benign diagnosis by MR imaging with gadolinium enhancement for both of simple and complex postmenopausal adnexal cystic masses. METHOD: We retrospectively examined the data of 121 postmenopausal patients who underwent surgery during a 3-years-period (from January, 2000 to December 2002) for adnexal mass under diagnosis of benign adnexal cysts based on MR imaging. RESULTS: Pathological examination identified two cases of malignancy among 121 cases diagnosed as benign by MR imaging. Among the cysts that revealed a simple pattern by MR imaging, 64/66 cases (97.0%) were benign histology and among the cysts that showed a complex pattern by MR imaging, 55/55 cases (100%) were benign histology. Among the cysts with diameter less than or equal to 10cm, 48/49 simple cysts and 32/32 complex cysts were benign histology. CONCLUSIONS: The diagnosis of benign adnexal mass in postmenopausal women by MR imaging was reliable. Conservative observation for postmenopausal patients of asymptomatic and small cysts under benign diagnosis based on MR imaging with gadolinium enhancement will be feasible even if the cysts appearances are complex, with careful follow-up program.     

Imaging findings of mimickers of hepatocellular carcinoma

Radiological imaging plays a crucial role in the diagnosis of hepatocellular carcinoma (HCC) as the noninvasive diagnosis of HCC in high-risk patients by typical imaging findings alone is widely adopted in major practice guidelines for HCC. While imaging techniques have markedly improved in detecting small liver lesions, they often detect incidental benign liver lesions and non-hepatocellular malignancy that can be misdiagnosed as HCC. The most common mimicker of HCC in cirrhotic liver is nontumorous arterioportal shunts that are seen as focal hypervascular liver lesions on dynamic contrast-enhanced cross-sectional imaging. Rapidly enhancing hemangiomas can be easily misdiagnosed as HCC especially on MR imaging with liver-specific contrast agent. Focal inflammatory liver lesions mimic HCC by demonstrating arterial-phase hypervascularity and subsequent washout on dynamic contrast-enhanced imaging. It is important to recognize the suggestive imaging findings for intrahepatic cholangiocarcinoma (CC) as the management of CC is largely different from that of HCC. There are other benign mimickers of HCC such as angiomyolipomas and focal nodular hyperplasia-like nodules. Recognition of their typical imaging findings can reduce false-positive HCC diagnosis.