Complex adnexal masses: detection and characterization with MR imaging--multivariate analysis

PURPOSE: To evaluate the accuracy of magnetic resonance (MR) imaging in the detection and characterization of complex adnexal masses, with particular reference to the findings predictive of malignancy, role of gadolinium-enhanced contrast material, and observer variability. MATERIALS AND METHODS: Preoperative MR imaging of the pelvis was performed in 128 consecutive patients with clinically or ultrasonographically detected complex adnexal masses. Histopathologic examination demonstrated 187 masses, 96 of which were malignant. MR imaging studies were prospectively and independently reviewed by two radiologists, one of whom reevaluated the studies after a 6-month interval. The predictive value of MR imaging findings was determined with multivariate logistic regression analysis. The value of gadolinium enhancement was assessed by using receiver operating characteristic analysis. Inter- and intraobserver variabilities were assessed by using weighted K statistics. RESULTS: Gadolinium-enhanced MR imaging depicted 176 (94%) of 187 adnexal masses, with an overall accuracy for the diagnosis of malignancy of 93%. The MR imaging findings that were most predictive of malignancy were necrosis in a solid lesion (odds ratio, 107) and vegetations in a cystic lesion (odds ratio, 40). Use of gadolinium-based contrast material contributed significantly to lesion characterization. Interobserver (K, 0.79-0.85) and intraobserver (K, 0.84-0.86) agreement were excellent. CONCLUSION: Gadolinium-enhanced MR imaging is highly accurate in the detection and characterization of complex adnexal masses, with excellent inter- and intraobserver agreement.     

不典型颅咽管瘤的MR诊断和误诊分析

目的 探讨不典型颅咽管瘤的MR表现,提高诊断的准确率.方法 回顾性分析8例经手术病理证实不典型颅咽管瘤的MR资料.结果 8例中囊性病灶3例,实性病灶2例,囊实性病灶3例.囊性病灶T1信号多变,囊壁明显强化且菲薄均匀;实性病灶扩散加权成像(DWI)序列呈低信号,增强呈"网格状"明显强化;囊实性病灶不均匀明显强化.4例鞍内鞍上型病灶,因正常垂体显示不清误诊为垂体瘤;2例鞍上型病灶,因瘤体明显强化误诊为生殖细胞瘤;2例鞍上型病灶,因与垂体柄、视交叉分界不清误诊为鞍区毛细胞型星形细胞瘤.结论 不典型颅咽管瘤的MR影像特征有助于其与垂体大腺瘤、生殖细胞瘤和毛细胞型星形细胞瘤相鉴别.     

MR imaging of ovarian hemorrhage

BACKGROUND: To review MR appearances of ovarian hemorrhage, and to describe its characteristic imaging findings. METHODS: 12 women (age range, 20-44, mean, 26 years) with suspected ovarian hemorrhage underwent pelvic MR examinations. We retrospectively reviewed MR findings regarding signal intensities, localization, and wall enhancement of adnexal masses, and signal intensities of ascites. RESULTS: Adnexal masses were detected in all cases. In eight cases, adnexal mass exhibited intermediate signal intensity on T1WI, and intermediate to low signal intensity on T2WI. In other case, adnexal mass exhibited marked hyperintensity on T1WI. In the remaining three cases, cystic mass with low signal intensity on T1WI and high signal intensity on T2WI was noted. Ascites was present in all cases, and showed intermediate signal on T1WI and intermediate to low signal on T2WI. CONCLUSIONS: In ovarian hemorrhage, hemorrhagic ascites and adnexal mass was visualized with specific MR signal intensity. Due to its sensitivity for identifying blood, MR imaging is useful in the diagnosis of ovarian hemorrhage, especially when ultrasonography findings are not definitive.     

肝脏囊性转移瘤的CT和MR征象的比较

目的:分析肝脏囊性转移瘤在CT和MR上的表现,比较CT和MR检查对囊性转移瘤的临床诊断价值.材料和方法:18例(共52个病灶)肝脏囊性转移瘤中10例行CT平扫和增强门脉期扫描.8例行MR T1WI和FMP-SPGR多期动态增强扫描.观察肿瘤的大小、形态、数目、囊壁和壁结节的强化情况.结果:2例为单发病灶外,其余均为多发病灶.病灶呈类圆形或椭圆形.CT上8例见到囊壁不规则增厚,其中6例可见向囊腔内突起的壁结节,1例内有分隔.2例薄壁且均匀的病灶误诊为肝囊肿.T1WI上,7例为低信号,1例为混杂信号.T2WI上,病灶均为明显高信号,2例信号均匀,6例信号不均匀,可见到壁结节为略低信号.增强动脉期所有病灶均无强化表现,门脉期和延迟期,可见到边缘环形强化和壁结节的强化.也有1例见到分隔.结论:CT和MR均可显示肝脏囊性转移瘤的特征,MR在显示病灶的出血、囊变、分隔和囊壁的情况等比CT更为敏感、可靠,在鉴别诊断方面价值更大.     

卵巢甲状腺肿的CT和MRI表现与病理对照分析

目的：探讨卵巢甲状腺肿(SO)的 CT、MR 影像学表现特点。方法回顾性分析经手术病理证实的10例 SO 患者的影像学及组织学资料,其中6例行 CT 平扫及增强扫描,4例行 MR 平扫及增强扫描。结果10例 SO 均为单发,呈分叶状或椭圆形,边缘清楚,直径<10 cm,4例伴有腹腔积液。6例囊实性,4例囊性,囊性部分密度及信号多变,CT 表现为低密度或高密度,4例出现高密度囊腔。MRI 表现为以 T1 WI 低信号、T2 WI 高信号或 T2 WI 低信号为主,1例表现为 T1 WI 低信号、T2 WI 极低信号的“真空征”,增强后实性部分及囊壁明显强化。结论SO 的 CT、MR 表现反映了其病理学特征,对其诊断及鉴别诊断有重要价值。     

胶质母细胞瘤的磁共振动态增强诊断

目的：探讨胶质母细胞瘤的MRI动态增强表现。方法：搜集67例胶质母细胞瘤患者的临床及影像资料,回顾性分析其磁共振动态增强表现特点。结果：67例胶质母细胞瘤中,单发者63例,多发者4例。MRI动态增强均呈明显不均质强化,其中28例呈花环样强化,15例呈环形强化,11例呈结节状强化,13例呈囊实性强化。时间-信号强度曲线20例（29.9%）呈缓升型,28例（42.0%）呈平台型,19例（28.4%）呈速升型。结论：胶质母细胞瘤的MRI动态增强具有一定的特征性,平台型时间-信号强度曲线有助于明确诊断。     

The role of magnetic resonance imaging and ultrasound in patients with adnexal masses

AIMS: To evaluate the accuracy of ultrasonography (US) and magnetic resonance imaging (MRI) in characterizing adnexal masses, and to determine which patients may benefit from MRI. METHODS: We prospectively studied 72 women (mean age 53 years, range 19 to 86 years) with clinically suspected adnexal masses. A single experienced sonographer performed transabdominal and transvaginal greyscale spectral and colour Doppler examinations. MRI was carried out on a 1.5T system using T1, T2 and fat-suppressed T1-weighted sequences before and after intravenous injection of gadolinium. The adnexal masses were categorized as benign or malignant without knowledge of clinical details, according to the imaging features which were compared with the surgical and pathological findings. RESULTS: For characterizing lesions as malignant, the sensitivity, specificity and accuracy of MRI were 96.6%, 83.7% and 88.9%, respectively, and of US were 100%, 39.5% and 63.9%, respectively. MRI was more specific (p<0.05) than US. Both MRI and US correctly diagnosed 17 (24%) cases with benign and 28 (39%) cases with malignant masses. MRI correctly diagnosed 19 (26%) cases with benign lesion(s), which on US were thought to be malignant. The age, menopausal status and CA-125 levels in these women made benign disease likely, but US features were suggestive of malignancy (large masses and solid-cystic lesions with nodules). CONCLUSION: MRI is more specific and accurate than US and Doppler assessment for characterizing adnexal masses. Women who clinically have a relatively low risk of malignancy but who have complex sonographic features may benefit from MRI.     

Tongue abscesses: MR imaging findings

BACKGROUND AND PURPOSE: A lingual abscess is difficult to diagnose in the absence of physical signs. MR imaging may provide an excellent and invaluable adjunct to clinical examination, but the literature is incomplete in defining the various MR imaging findings of abscess. The objective of this study was to determine the MR imaging features of tongue abscesses. METHODS: Seven surgically proved tongue abscesses were evaluated with MR imaging. Four patients underwent MR imaging because of suspected tumor, and 3 patients, to show the extent and precise anatomic location of the lesion. Lesions were assessed with regard to the location, size, signal-intensity characteristics, and pattern of contrast enhancement. RESULTS: Five lesions were located in the anterior tongue and 2, in the posterior tongue. The central parts of 4 anterior tongue abscesses were hypointense, surrounded by a hyperintense wall on T1-weighted precontrast images. On postcontrast images, marked wall enhancement was detected. On T2-weighted images, a markedly hyperintense central part surrounded by a hypointense rim was seen. In 2 of these patients, there was a hypointense halo surrounding the wall (target sign). In 3 patients, a perilesional hyperintense area that enhanced diffusely after contrast administration was detected on T2-weighted images. The smallest lesion located in the anterior tongue was hypointense on T1-weighted images and enhanced diffusely on postcontrast images. On T2-weighted images, a markedly hyperintense central part surrounded by a mildly hyperintense peripheral part was depicted. Posterior tongue lesions appeared as polypoid ill-defined masses and were hypointense on T1-weighted images and heterogeneously hyperintense on T2-weighted images. On postcontrast images, the lesion in 1 patient showed diffuse and heterogeneous contrast enhancement, whereas the lesion in another patient enhanced peripherally. The lesions were totally excised in 4 patients and drained with surgical incisions in 3 patients. No recurrence was detected on follow-up. CONCLUSION: An abscess typically presents as a cystic lesion surrounded by an enhancing capsule formation, but lesions may also present as solid masses that enhance diffusely or peripherally.     

Complex renal cysts: findings on MR imaging.

OBJECTIVE: We retrospectively evaluated our experience with complex cystic renal masses on MR imaging, using T1-weighted, T2-weighted, and gadolinium-enhanced images, to determine whether imaging features could permit distinction between benign and malignant lesions. MATERIALS AND METHODS: Thirty-seven patients with complex cystic renal lesions were included in this retrospective study. The patients selected had undergone T1-weighted, T2-weighted, and gadolinium-enhanced MR imaging examinations using 1.5-T scanners, with at least one of the following findings: cyst fluid of heterogeneous signal intensity, mural irregularity, septa, mural masses or nodules, increased mural thickness, or intense mural enhancement. The diagnosis was established by histology in 19 patients and by follow-up studies in the remaining 18 patients. RESULTS: Fifty-five complex renal cystic lesions were present in the 37 patients. Among the 55 lesions, of 37 that contained fluid of a heterogeneous signal intensity, eight were malignant (22%); of 16 with irregular walls, 10 were malignant (63%); of four with septa, two were malignant (50%); of four with mural masses or nodules, three were malignant (75%); of 14 with a thick wall (>2 mm), 10 were malignant (71%); and of 32 with intense mural enhancement, 14 were malignant (44%). As independent variables, mural irregularity, mural masses or nodules, increased mural thickness, and intense mural enhancement each were highly associated with malignancy (p = .0003-.0022). The combination of mural irregularity and intense mural enhancement had the highest correlation with malignancy (p = .0002). CONCLUSION: The combination of mural irregularity and intense mural enhancement is a strong predictor of malignancy in renal cystic lesions. However, the appearance of benign and malignant lesions may overlap, suggesting that distinct separation of these entities is not currently possible in all cases with MR imaging.     

Metastatic liver tumor from cystic ovarian carcinomas: CT and MRI appearance.

OBJECTIVE: The initial and follow-up CT and MRI images of ten patients with hepatic metastases from ovarian tumors were retrospectively analyzed to establish their features and sequential changes in appearance. MATERIALS AND METHODS: Ten patients with hepatic metastasis from ovarian tumors received initial and follow-up CT and MRI examinations. Six patients were followed up every two to three weeks before surgical tumor resection. Both CT and MR images were analyzed by two radiologists. RESULTS: A total of fourteen lesions were detected by CT and MRI in 10 patients. All 14 lesions were demonstrated as areas of marked hyperintensity on T2-weighted MRI. Eleven cyst-like tumors were demonstrated as round or oval low density lesions on CT and as areas of hypointensity on T1-weighted imaging. Three lesions were shown as solid masses with slightly low attenuation at the initial CT examination and slightly low or iso-intensity areas on T1-weighted imaging, and these lesions showed early peripheral globular enhancement and delayed enhancement on contrast-enhanced CT and MR imaging. Cystic formation was observed two to three weeks later after initial study in all the 3 solid lesions. Rapid subcapsular effusion, which showed obvious enhancement on delayed Gd-DTPA enhanced MR imaging, was observed in two patients. CONCLUSION: The hepatic metastatic tumor from cystic ovarian carcinoma may manifest as a well-defined cystic lesion or as a solid mass, and the solid mass shows delayed enhancement on contrast-enhanced CT and MR imaging. Furthermore, rapid cystic formation and rapid subcapsular extension is frequently seen.     

Focal nodular hyperplasia: morphologic and functional information from MR imaging with gadobenate dimeglumine.

PURPOSE: To determine whether gadobenate dimeglumine (Gd-BOPTA) is able to provide morphologic and functional information for characterization of focal nodular hyperplasia (FNH). MATERIALS AND METHODS: Sixty-three consecutive patients with proved FNH were retrospectively examined. Magnetic resonance (MR) imaging with T2-weighted turbo spin-echo and T1-weighted gradient-echo sequences was performed. Images were acquired prior to and during the dynamic phase of contrast-material enhancement and 1-3 hours after administration of 0.1 mmol/kg Gd-BOPTA. Qualitative analysis of signal intensity and homogeneity on images in the various phases of the MR study and examination for the presence of central scar or atypical features were performed. On the basis of features observed in the precontrast and dynamic phases, lesions were defined as typical or atypical. Intensity and enhancement patterns of the lesions and scars were also evaluated in the delayed phase. RESULTS: One hundred FNHs were depicted on MR images. Seventy-nine of 100 lesions demonstrated typical morphologic and enhancement characteristics. On delayed phase images, 72% of 100 FNHs appeared hyperintense; 21%, isointense; and 7%, slightly hypointense. The delayed pattern of enhancement was homogeneous, heterogeneous, and peripheral in 58%, 22%, and 20% of 100 FNHs, respectively. Atypical morphologic features and lesion and/or scar enhancement were observed in 21 of 100 FNHs. On delayed phase images, 76% of 100 atypical FNHs appeared hyperintense, 14% isointense, and 10% slightly hypointense. Hyperintensity and isointensity allowed the correct characterization in 90% of atypical FNHs. CONCLUSION: Gd-BOPTA during both dynamic and delayed phases provides morphologic and functional information for the characterization of FNH.     

肾嗜酸细胞瘤的影像学诊断

目的:探讨肾嗜酸细胞瘤(RO)的影像学表现,以提高对其诊断的准确性。方法:回顾性分析经病理证实的12例RO患者的影像资料。12例均行MSCT平扫及多期增强扫描,包括肾皮质期、髓质期和排泄期(5例)增强扫描;有3例同时行MRI检查。结果:CT平扫示12例病灶均为单发,7例位于左肾,5例位于右肾,最大径2.0~11.6cm,平均5.8cm,<3.0cm者3例。增强扫描:肾皮质期示10例病灶明显强化,其中8例强化低于肾皮质,2例强化接近于肾皮质;肾髓质期示7例病灶强化程度下降并低于肾脏髓质的密度,3例病灶持续强化、于排泄期见密度开始下降,2例病灶在皮质期~排泄期表现为持续强化;6例病灶内可见星芒样瘢痕,8例有完整包膜,3例可见钙化。3例病灶于MRIT1WI上呈等、低信号,T2WI呈相对均匀的高信号,3例均见完整包膜。结论:RO的影像学表现有一定特征性,多表现为增强后均匀强化,无囊变或坏死,T2WI上可见完整的低信号包膜,有助于同各类型肾癌鉴别。     

Prediction rule for characterization of hepatic lesions revealed on MR imaging: estimation of malignancy

OBJECTIVE: Our aims were to establish factors that are most predictive of hepatic lesion malignancy and to formulate a prediction rule. MATERIALS AND METHODS: A cross-sectional study of 227 abdominal MR imaging examinations revealed 85 lesions in 67 patients (29 men, 38 women; age range, 29-78 years; mean age, 51.4 years) who were being examined for primary malignancy (n = 42) or unknown lesion characterization (n = 25). All were referred for MR imaging after CT or sonography. Patient demographics (age, sex, history of malignancy), lesion size and morphology, quantitative T2 calculation, and pattern of enhancement on gadopentetate dimeglumine administration were evaluated for predictive ability. RESULTS: Thirty-two liver lesions were malignant (eight colon cancer, five breast cancer, four cervical cancer, three renal cancer, three lung cancer, and nine miscellaneous cancers), 53 were benign (37 hemangiomas, 15 cysts, and one focal nodular hyperplasia). Calculated T2 relaxation times (mean +/- standard deviation [SD]) were as follows: malignant tumors (91.72 +/- 21.9 msec), hemangiomas (136.1 +/- 26.3 msec), cysts (284.1 +/- 38.2 msec) (p < 0.001). Logistic regression analysis indicated that lesion size and sex and age of patient were not significant independent predictors (p > 0.05). However, the combination of a history of malignancy, T2 value, and gadopentetate dimeglumine-enhancement pattern allowed generation of a prediction rule with an area under the receiver operating characteristic curve of 0.95. The patient's weight, lesion morphology, and cell type of the primary malignancy did not provide additional predictive information (p > 0.2). CONCLUSION: We recommend using the combination of T2 quantification and patient history of malignancy before deciding to administer gadopentetate dimeglumine for optimal lesion characterization, especially for equivocal lesions with T2 values between 90 and 130 msec. These factors allowed the construction of a prediction rule for lesion characterization.     

Developing a prediction rule to assess hepatic malignancy in patients with cirrhosis

OBJECTIVE: The objectives of our study were to identify independent clinical, demographic, and MR imaging correlates of malignancy in patients with cirrhosis and to develop a predictive model based on identified correlates of malignancy. MATERIALS AND METHODS: Sixty examinations of 58 patients with biopsy proof of lesions suggestive of hepatocellular carcinoma on MR imaging were retrospectively reviewed. The signal intensity of the lesion on T2-weighted imaging and dynamic gadolinium-enhanced imaging, the size of the lesion, and the number of suspicious lesions were recorded; in addition, patient age and sex, alpha-fetoprotein level, and hepatitis C viral genotype were noted. The association between malignancy and each predictor variable was evaluated using the chi-square test or the two-group t test. The final logistic regression model included the variables that were shown to have a significant association with malignancy and the clinically relevant predictors. We used the adjusted odds ratios to measure the strength of each association. The discriminant ability of the model for detecting hepatic malignancy was assessed using receiver operating characteristic curve analysis. RESULTS: The prevalence of hepatic malignancy in our study population was 64%. The area under the receiver operating characteristic curve for the logistic regression model was 0.82. Venous washout (odds ratio = 9.2), alpha-fetoprotein level (odds ratio = 3.2), and number of lesions (odds ratio = 1.5) were significant predictors for malignancy (p < 0.05). When arterial enhancement and venous washout were either both present or both absent, alpha-fetoprotein level contributed little to the prediction of malignancy. CONCLUSION: The MR characteristics of hepatic lesions during the dynamic venous phase in conjunction with the serum alpha-fetoprotein level and number of lesions are predictors of hepatic malignancy. The use of these predictors can facilitate explicit estimation of malignancy in individuals with underlying cirrhosis, potentially improving clinical decision-making.     

MR imaging-detected breast lesions: histopathologic correlation of lesion characteristics and signal intensity data

OBJECTIVE: The aim of our study was to differentiate benign from malignant breast lesions that had been detected exclusively on MR imaging by analyzing qualitative and quantitative lesion characteristics. MATERIALS AND METHODS: We performed 51 MR imaging-guided breast interventions (41 preoperative lesion localizations and 10 large-core needle biopsies) in 45 patients with exclusively MR imaging-detected lesions. All patients had previously undergone diagnostic dynamic contrast-enhanced MR imaging of the breast with a double breast coil at 1.0 T (n = 36) or 1.5 T (n = 15). The diagnostic MR images were evaluated on a workstation. Lesion morphology (size, shape, margin type, enhancement pattern), signal intensity parameters (time to peak enhancement, maximum slope of enhancement curve, washout, relative water content), and scores analogous to the Breast Imaging Reporting and Data System (BI-RADS) categories were correlated with histology. RESULTS: Histology revealed malignancy in 37.3% (19/51) of the lesions. The positive predictive value for malignancy of exclusively MR imaging-detectable lesions increased as the analogous BI-RADS category increased. Late inhomogeneous contrast enhancement was the only morphologic criterion that was statistically significantly correlated with malignancy. Malignant and benign lesions did not differ significantly in any of the quantitatively evaluated signal intensity parameters. Carcinomas showed a tendency toward faster and stronger enhancement and stronger washout. CONCLUSION: The classification of exclusively MR imaging-detectable breast lesions according to a combination of morphologic and perfusion parameters including the late enhancement pattern helps identify the lesions for which interventional MR imaging is required. Quantitative signal intensity data alone do not suffice.     

毛细胞型星形细胞瘤的CT、MRI表现及病理学基础

目的:探讨脑内毛细胞型星形细胞瘤(PA)的CT、MRI表现及病理学基础,以提高对此病的认识.材料和方法:回顾性分析经手术病理证实的脑内典型PA 13例的CT与MRI表现.结果:位于小脑半球4例、小脑蚓部7例、右侧大脑半球2例.病变大小2.3cm×2.0cm×2.7cm～4.5cm×4.8cm×5.6cm.实性病变3例,CT平扫呈等密度软组织肿块,T1WI呈等信号,T2WI呈长信号或长信号中见少量短信号的混杂信号,CT及MRI增强后均表现为均质或不均质明显增强,其中2例病灶中心见少量无增强的低信号区,1例CT平扫见钙化灶.囊实性10例,MRI平扫显示肿瘤囊性部分呈长T1、长T2信号,实性部分呈等T1长T2信号,增强扫描实性部分明显增强,囊性部分无增强,3例见明显增强壁结节,2例病变呈多房性,增强后分隔明显增强,其中1例见短T1、长T2出血灶 .结论:脑内PA的CT与MRI表现具有一定的特征性,结合临床资料有助于术前诊断.     

Biliary hamartomas: solitary and multiple lesions shown on current MR techniques including gadolinium enhancement.

The purpose of this study was to describe the magnetic resonance (MR) imaging features of biliary hamartomas on T1- and T2-weighted and gadolinium-enhanced sequences, and to correlate these findings with histopathology. MR imaging findings in four patients with pathologically proved biliary hamartomas are described. In all patients, MR imaging sequences, including T1- and T2-weighted and early and late gadolinium-enhanced images, were retrospectively evaluated for the size, morphology, signal intensity, and enhancement pattern of the lesions. Correlation was made between the MR imaging findings and histopathology. Biliary hamartomas ranged in diameter from 0.5 to 1.5 cm. Lesions were solitary in one patient and numerous in three patients. In all patients, the lesions were low signal on T1-weighted images and high signal and well-defined on T2-weighted images and demonstrated thin rim enhancement on early post-gadolinium images that persisted on late post-gadolinium images. No appreciable central enhancement of the lesions was observed. At histopathology, the lesions were composed of cystic spaces and fibrous stroma. Lesions showed compressed liver parenchyma surrounding the lesions (three cases) and inflammatory cell infiltrate (one case), which correlated with the rim enhancement on the gadolinium-enhanced MR images. Most of the biliary hamartomas in our small series were less than 1 cm in diameter and of high signal intensity on T2-weighted images, and had a thin rim of enhancement on early and late post-gadolinium images. The imaging features were explainable by the underlying histopathology. In patients with known malignancy, caution should be exercised not to misinterpret these lesions as metastases due to the presence of thin rim enhancement. J. Magn. Reson Imaging 1999;10:196-201, 1999.     

Nodular fasciitis in the head and neck: CT and MR imaging findings

BACKGROUND AND PURPOSE: The purpose of this study was to describe the CT and MR imaging findings of nodular fasciitis occurring in the head and neck region. METHODS: CT (n = 6) and MR (n = 4) images obtained from 7 patients (3 men and 4 women; mean age, 19.4 years; age range, 1-48 years) with surgically confirmed nodular fasciitis in the head and neck were retrospectively reviewed. All patients presented with a palpable mass in the head and neck that was noticed 1-3 months earlier: 5 in the face, one in the occipital scalp, and the remaining one in the supraclavicular fossa. We investigated the CT and MR imaging characteristics with emphasis on the location, size, internal content, margin, enhancement pattern, and signal intensity of the lesion. RESULTS: All lesions appeared as a discrete mass on imaging, ranging from 1.0 cm to 4.6 cm in diameter (mean, 2.2 cm). Six lesions, all of which appeared benign, were located in the subcutaneous tissue superficial to the deep cervical fascia. The remaining lesion was located deep to the temporalis muscle and showed an aggressive imaging appearance, markedly eroding the bony orbit and skull. Five lesions were solid, and 2 lesions were partly or completely cystic in appearance. Five lesions were well defined, whereas 2 lesions were ill defined. Four of 5 solid lesions showed moderate to marked diffuse enhancement, whereas the remaining lesion demonstrated mild enhancement. Two cystic lesions showed peripheral, nodular, or rim-like enhancement. Compared with muscle, both solid lesions had isointense signal intensity on T1-weighted images and hyperintense signal intensity on T2-weighted images, whereas the signal intensity of the solid portions of the deep-seated, partly cystic lesion was isointense on both T1-weighted and T2-weighted images. CONCLUSION: Although rare, nodular fasciitis occurs as a discrete solid or cystic mass in the head and neck, depending on the predominant stromal components. When one sees a head and neck mass with a superficial location and moderate to marked enhancement on CT and MR imaging, nodular fasciitis should be included in the differential diagnosis, especially in patients with a recently developed, rapidly growing mass and a history of recent trauma.     

Complex US adnexal masses during pregnancy: Is pelvic MR imaging accurate for characterization?

ObjectiveTo retrospectively evaluate the accuracy of pelvic magnetic resonance (MR) imaging for the characterization of complex sonographic adnexal masses discovered in women during pregnancy.Study designThe study population comprised 31 pregnant women (median age: 32 years (range: 19–42); mean gestation age of 16 weeks) referred to our institution for MR imaging for characterization of an adnexal mass discovered incidentally during routine ultrasound (US) for other indications. The population comprised of 31 women, with 36 adnexal lesions (mean size: 103 mm [range: 20–290]), of which 27 were benign and 9 were malignant masses. Prospective US and MR reports were reviewed to determine the presence of a benign or malignant lesion. Two radiologists (R1 and R2) blinded to the final outcome, retrospectively evaluated the MR images using the criteria based on the A_DNEXMR-S_CORE and classified the lesion as benign or malignant. The reference standard was surgical pathology or at least a 1-year imaging follow-up.ResultsProspective US and MR imaging correctly identified the diagnosis in 27/36 (75%) (95% confidence interval (CI): 58.9%–86.2%) and in 32/36 (88.9%) (95% CI: 74.6%–95.6%) of lesions, respectively. MR imaging with A_DNEXMR-S_CORE allowed a correct diagnosis in 32/36 (88.9%) (95% CI: 74.6%–95.6%) of lesions for R1 and in 30/36 (83.3%) (95% CI: 68.1%–92.1%) of lesions for R2. The sensitivities and specificities of MR imaging using the MR A_DNEXMR-S_CORE were 100% (95% CI: 70.1%–1000%) for both readers and 85.1% (95% CI: 67.5%–94%) and 77.7% (95% CI: 59.2%–89.4%) for R1 and R2, respectively. No malignancy was classified as benign using MR criteria. The reproducibility between the two readers was almost perfect, with a kappa of 0.914.ConclusionMR imaging is highly accurate for the characterization of complex adnexal masses incidentally discovered during pregnancy.Clinical relevanceMR imaging can accurately characterize adnexal masses in pregnancy and could be useful in opting for expectant management until delivery.     

Gadolinium-DOTA enhanced MR imaging of adnexal tumors

We conducted a retrospective study to assess the potential of contrast enhanced magnetic resonance (MR) imaging in evaluating adnexal tumors. Sixty patients with a total of 77 pelvic lesions underwent MR imaging at 1.5 T and transabdominal ultrasound (US). Precontrast T1- and T2-weighted and Gd-DOTA enhanced T1-weighted MR images were obtained. Diagnoses were proved by surgery in 57 patients. Of the 77 lesions, 54 masses were of ovarian origin, including 12 malignant disorders. Ultrasound demonstrated the lesions in 92%, whereas the sensitivity of unenhanced T2-weighted and postcontrast MR images was 98 and 96%, respectively. Compared to the T2-weighted images, postcontrast MR imaging showed superior overall tumor delineation, assessment of intratumoral architecture, and definition of tumor origin. Contrast enhancement of tumors did not differ significantly between normal ovary and benign and malignant lesions. All modalities were unable to predict malignancy of complex lesions. Based on our study, US remains the screening modality of choice in the evaluation of adnexal tumors. Contrast enhanced MR imaging may be valuable for assessing complex lesions or when the origin of the mass cannot be determined by US. Using contrast enhanced T1-weighted images instead of T2-weighted images may lead to a significant reduction in acquisition time.