Atypical focal nodular hyperplasia of the liver: imaging features of nonspecific and liver-specific MR contrast agents

OBJECTIVE: The objective of our study was to describe the functional and differential uptake features of atypical focal nodular hyperplasia using different MR contrast agents and to evaluate their potential role in the diagnosis and characterization of focal nodular hyperplasia. MATERIALS AND METHODS: Contrast-enhanced MR images of 45 patients with 85 focal nodular hyperplasia lesions were retrospectively reviewed. In these patients, sonographic findings were nonspecific (n = 37), or CT features were inconclusive (n = 8). Non-liver specific gadolinium chelates were used in 18 patients (48 lesions) suspected of having either focal nodular hyperplasia or hemangioma. The following liver-specific agents were used in patients with suspected focal nodular hyperplasia or metastases: mangafodipir trisodium, 30 patients (55 lesions); ferumoxides, six patients (16 lesions); and SHU 555 A, six patients (six lesions). Individual lesions were quantified by signal intensity and assessed qualitatively by homogeneity, contrast enhancement, and presence of a central scar. RESULTS: At unenhanced MR imaging, the triad of homogeneity, isointensity, and central scar was found in 22% of the focal nodular hyperplasia lesions. On mangafodipir trisodium-enhanced T1-weighted images, all focal nodular hyperplasia lesions showed contrast uptake: in 64% of the lesions, uptake was equal to parenchyma; 25%, greater than the parenchyma; and 11%, less than the parenchyma. On iron oxide-enhanced T2-weighted images, all focal nodular hyperplasia lesions showed uptake of the contrast agent, but contrast uptake in the lesions was less than in the surrounding parenchyma. Dynamic gadolinium chelate-enhanced MR imaging showed early and vigorous enhancement of focal nodular hyperplasia lesions with rapid washout in 88%. Atypical imaging features of the lesions included hyperintensity on T1-weighted images, necrosis and hemorrhage, and inhomogeneous or only minimal contrast uptake. CONCLUSION: For patients in whom the diagnosis of focal nodular hyperplasia cannot be established on unenhanced or gadolinium-enhanced MR imaging, homogeneous uptake of liver-specific contrast agent with better delineation of central scar may help to make a confident diagnosis of focal nodular hyperplasia.     

Magnetic resonance imaging of hepatic focal lesions: dynamic contrastographic evaluation with gadolinium versus reticulo-endothelial hepato-specific contrast media

PURPOSE: To compare the potentials of AMI-25 (Endoren) to those of Gadolinium with the dynamic contrast-enhanced technique in the differential diagnosis of focal liver lesions. MATERIAL AND METHODS: Forty patients with at least one focal liver lesion diagnosed at US underwent MRI. We used a 1.5 T unit and employed single-shot half-Fourier T2-weighted FSE and spoiled gradient-echo T1-weighted sequences before and after Gadolinium injection. Multiple acquisitions were obtained during the arterial, portal and delayed phases. Twenty-four to 48 hours later T2*-weighted GRE and SPGR/90 degrees sequences were obtained after AMI-25 administration. In the characterization of solid lesions the gold standard was biopsy performed with a shearing needle; for the diagnosis of angiomas and of 11 metastatic lesions we considered follow-up and clinical data as important diagnostic elements. RESULTS: We found 12 hepatocarcinomas, 14 metastases, 4 cases of focal nodular hyperplasia (FNH), 4 adenomas and 6 angiomas. The diagnosis was correct and confirmed by the conventional examination in all cases but 2 adenomatous lesions and 2 angiomas. Precontrast studies showed slight hyperintensity in 2 of 4 cases of FNH, while the other 2 lesions appeared isointense and were therefore detected only on postcontrast images, where there was contrast agent uptake during the arterial phase and rapid washout. We found only one central scar hyperintense on T2- and hypointense on T1-weighted images. After AMI-25 administration all lesions appeared isointense to surrounding parenchyma on T2* GRE sequences. Adenomas were isointense in the precontrast phase and postcontrast 3 of them showed strong Gadolinium uptake and rapid washout. After AMI-25 two of the 4 lesions were hyperintense while the other two were isointense to the parenchyma. Four of 6 angiomas exhibited a typical pattern characterized by signal hyperintensity on T2-weighted sequences and on AMI-25-enhanced T1- and T2-weighted sequences. Two angiomas were supposed to be of malignant nature but histology showed the presence of a strong fibrotic component. Hepatocarcinomas could be detected on precontrast images. After Gadolinium administration 10 lesions appeared hyperintense in the arterial phase and 2 were hypointense. After AMI-25 all lesions exhibited homogeneous signal hyperintensity and appeared slightly bigger than on Gadolinium-enhanced images. The metastases were only partly demonstrated by MRI. Postgadolinium studies showed 13 lesions with hyperintense signal in the portal phase. AMI-25 administration detected 14 lesions that appeared slightly bigger than on Gadolinium-enhanced images. CONCLUSIONS: AMI-25 can help also in characterizing primary lesions with an atypical signal pattern after contrast agent administration thanks to its intrinsic capability of accumulating in benign lesions. However it remains difficult to characterize well differentiated hepatocarcinomas and adenomas. Finally, AMI-25 improves MR capabilities in detecting secondary lesions and possible satellite nodules.     

Invasive pulmonary aspergillosis: evaluation with MR imaging

Eleven patients with suspected invasive pulmonary aspergillosis underwent magnetic resonance (MR) imaging. Images were obtained with standard spin-echo sequences and electrocardiographic triggering before and after intravenous administration of gadolinium diethylenetriaminepentaacetic acid. Thirty-seven of 48 lesions seen on MR images were nodular infiltrates; 34 of these had a targetlike appearance, with hypointense centers and iso- or hyperintense rims. Twenty-three of 37 nodular lesions contained areas of hyperintensity on T1-weighted images. All 37 had enhanced rims on postcontrast MR images. The remaining 11 lesions were segmental infiltrates, seven of which were predominantly hyperintense on T1-weighted images. In one patient with nodular lesions, MR imaging findings were correlated with those from pathologic analysis of a resected upper lobe. Areas of hyperintensity corresponded to subacute hemorrhage permeated by Aspergillus organisms. The authors believe that the typical targetlike appearance of nodular lesions on MR images and the potential that MR imaging has to reveal hemorrhagic content will prove useful in the early diagnosis of invasive pulmonary aspergillosis.     

Focal nodular hyperplasia of the liver: MR findings in 35 proved cases

MR images of 28 patients with 35 lesions of hepatic focal nodular hyperplasia were reviewed to determine the frequency of findings considered typical of this condition (isointensity on T1- and T2-weighted pulse sequences, a central hyperintense scar on T2-weighted images, and homogeneous signal intensity). Fifteen lesions were imaged at 0.6 T with T1- and T2-weighted spin-echo (SE) pulse sequences; 20 lesions were imaged at 1.5 T with T1-weighted SE and gradient-echo pulse sequences and T2-weighted SE pulse sequences. Diagnosis of focal nodular hyperplasia was made pathologically in 25 patients, with nuclear scintigraphy in four, and with follow-up imaging in six. Only seven lesions (20%) were isointense relative to normal liver on both T1- and T2-weighted images. On T1-weighted SE images, 21 lesions (60%) were isointense relative to normal liver, 12 (34%) were hypointense, and two (6%) were hyperintense. On T2-weighted SE images, 12 lesions (34%) were isointense and 23 (66%) were hyperintense relative to normal liver. A central scar was present in 17 lesions (49%) and was hypointense relative to the lesion on T1-weighted images and hyperintense on T2-weighted images. Twenty lesions (57%) were of homogeneous signal intensity throughout the lesion, except for the presence of a central scar. All three MR imaging characteristics were present in three cases (9%). We conclude that hepatic focal nodular hyperplasia has a wide range of signal intensity on MR imaging.     

Focal nodular hyperplasia of the liver: MR imaging and pathologic correlation in 37 patients.

Thirty-seven patients with 48 lesions of focal nodular hyperplasia (FNH) underwent preoperative magnetic resonance (MR) examination and surgical resection. Sixteen lesions were imaged at 0.5 T with T1- and T2-weighted spin-echo sequences; 32 lesions were imaged at 2 T with T1-and T2-weighted spin-echo and gradient-recalled-echo sequences. Contrast material-enhanced MR imaging was performed in 20 lesions. MR imaging failed to depict six tumors that were less than 3 cm in diameter. Typical appearance was present in 18 of the 42 (43%) lesions seen at MR. Atypical lesion features included no scar (n = 15), hypointense scar on T2-weighted images (n = 7), pseudocapsule (n = 6), strong hyperintense lesion on T2-weighted images (n = 3), diffuse hyperintensity on T1-weighted images (n = 3), and heterogeneous lesion (n = 1). Comparison between findings at MR imaging and at histopathologic examination was performed in 38 lesions: There was good correlation between presence and size of the scar on both examinations. In 13 of 20 (65%) of the hyperintense scars on T2-weighted images, edema was prominent, whereas in five of the seven (71%) hypointense scars on T2-weighted images, edema was absent or low.     

MRI of focal nodular hyperplasia (FNH) with gadobenate dimeglumine (Gd-BOPTA) and SPIO (ferumoxides): an intra-individual comparison

PURPOSE: To compare the efficacy of two different MR contrast agents for the detection and diagnosis of focal nodular hyperplasia (FNH). MATERIALS AND METHODS: Fifty patients with 83 FNH lesions detected on spiral CT were studied in two different MRI sessions with Gd-BOPTA (MultiHance) and ferumoxides (Endorem). MRI with Gd-BOPTA was performed precontrast (T1wGRE and T2wTSE sequences) and during the dynamic and late (1-3 hours) phases after injection (T1wGRE sequences only). MRI with ferumoxides (T1wGRE and T2wTSE sequences) was performed before and at least 30 minutes after injection. Hyper- or isointensity of FNH in the late phase was considered typical for Gd-BOPTA, while isointensity or lesion hypointensity was considered typical for ferumoxides. RESULTS: With Gd-BOPTA, 83 FNH lesions (100%) appeared hyperintense during the arterial phase of dynamic MRI. All but one lesion was iso- or slightly hyperintense in the portal-venous and equilibrium phases. In the late phase, 81 FNH lesions were hyper- or isointense to the surrounding parenchyma, with two lesions appearing slightly hypointense. With ferumoxides, a significant (P < 0.001) number (21/83, 25.3%) of FNH lesions (mean diameter = 16.8 +/- 6.6 mm) were not visible. Of the visible FNH lesions, 38/62 were slightly hyperintense, and 24/62 were isointense to the surrounding parenchyma on the T2wTSE images. On the T1wGRE images, 42/62 lesions were isointense, 19/62 were slightly hyperintense, and one lesion was slightly hypointense. Seventeen lesions in 12 patients with previous neoplasia were all detected after Gd-BOPTA administration, whereas only nine of these 17 lesions (52.9%) were detected after ferumoxide administration. Two of these nine lesions showed atypical enhancement features. CONCLUSION: Gd-BOPTA-enhanced MRI is significantly better than ferumoxide-enhanced MRI for the identification and characterization of FNH.     

Infantile fibromatosis in childhood: findings on MR imaging and pathologic correlation

AIM: The objective of this study was to analyse the MR imaging findings of infantile fibromatosis of childhood and to correlate them with histopathological features. MATERIALS AND METHODS: Seven patients with histologically proven infantile fibromatosis were included in this study. The findings on MR images were retrospectively evaluated and then correlated with the pathological features. Findings on MR imaging evaluated included signal intensity, extent of hyperintense area on T2-weighted images, margins of the lesion, the degree and pattern of enhancement and the presence of fatty tissue. Pathological features evaluated included cellularity, collagenization, and myxoid change. A five point scale was used for the evaluation of the extent of hyperintense area on MR imaging, and each of pathological features. RESULTS: On T1-weighted images, the lesions were iso-intense in two patients; iso- and hypointense in three; and iso-, hypo- and hyperintense in two. On T2-weighted images, iso-, hypo- and hyperintense areas were mixed in all patients, the hyperintense area being the largest portion of the lesion. The margins of the lesions were infiltrative in four patients (57%), smooth in two (29%) and mixed in one (14%). Enhancement was marked in five patients (72%) and diffuse in five (71%). Regardless of the hyperintense signal intensity on T2-weighted images, the grades of each pathologic feature were variable. CONCLUSION: Infantile fibromatosis on MR imaging causes an enhancing mass, that is largely hyperintense on T2-weighted images. Areas of high signal intensity on T2-weighted images corresponded to variable grades of cellularity, collagenization, or myxoid change.     

Imaging findings in three cases of the nodular type of muscular sarcoidosis

OBJECTIVE: Sarcoidosis is a granulomatous multisystem disorder that may uncommonly involve muscle. We report the sonographic and MRI findings in three cases of the nodular type of muscular sarcoidosis. CONCLUSION: Intramuscular hypoechoic well-defined nodules in young patients or patients with a history of sarcoidosis suggest the diagnosis of intramuscular sarcoid. MRI is useful in detecting muscle sarcoid, evaluating the extent and distribution of muscle involvement, and monitoring the patient during follow-up after steroid therapy. MRI showed nodules that were iso- or hyperintense relative to muscle on T1-weighted sequences. On T2-weighted images and STIR sequences, we observed numerous intramuscular nodules of homogeneous high signal intensity. All nodules enhanced homogeneously on contrast-enhanced T1-weighted sequences. Disappearance of all nodules was seen on follow-up sonograms and MR images after patients had received steroid therapy.     

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.     

MR imaging of hepatic focal nodular hyperplasia: characterization and distinction from primary malignant hepatic tumors

Spin-echo MR imaging at 0.35 T was used to image hepatic focal nodular hyperplasia (FNH) and to attempt to distinguish it from primary malignant hepatic tumors. There were six FNH and 10 malignant tumors including seven hepatocellular carcinomas, two cholangiocarcinomas, and one hepatoblastoma. Our results show that FNH has a fairly consistent appearance, dissimilar from that of malignant primary hepatic tumors. Four of six FNH lesions were isointense (except for a central scar in three) and indistinguishable from normal hepatic parenchyma on all pulse sequences, whereas two of six were homogeneous but slightly hyperintense on T2-weighted sequences. Furthermore, a central hyperintense scar was seen in three of six lesions on T2-weighted sequences. In contrast, each of the malignant primary hepatic tumors was hyperintense on T2-weighted sequences and seven of 10 were hypointense on T1-weighted sequences; in nine of 10, heterogeneous areas of intensity were noted. In two fibrolamellar hepatocellular carcinomas a central scar was seen that was hypointense on all pulse sequences. By using quantitative data, the best characterization was obtained by using lesion/normal-liver intensity ratios from a T2-weighted sequence; all FNH had a ratio less than 1.33, while in nine of 10 primary malignant tumors it was greater than 1.41. We conclude that focal nodular hyperplasia may have a consistent appearance on spin-echo MR imaging and probably can be distinguished from primary malignant lesions in most instances.     

Nodular fasciitis: MRI appearance and literature review

OBJECTIVE: To describe the MRI features of nodular fasciitis and to review the clinical, MRI and histologic aspects of the tumor. DESIGN AND PATIENTS: Three patients with biopsy-proven nodular fasciitis were selected for a retrospective study. A literature review was also carried out. RESULTS AND CONCLUSIONS: All the lesions appeared slightly hyperintense to skeletal muscle on T1-weighted images, and hyperintense on T2-weighted images with fat saturation [either frequency saturation or Short TI Inversion Recovery (STIR) sequences]. Two enhanced homogeneously after intravenous gadolinium, whereas the third showed heterogeneous enhancement with a nonenhancing area. Despite the difference in enhancing patterns, the histologic appearances of these lesions were similar. Our study shows that the MRI appearance of nodular fasciitis may not be related to the location of lesion. It is thought that the age of nodular fasciitis may reflect its gross morphology, and it is possible that the MRI and histologic appearances could correlate with the age of the lesion, but it would require a larger series to evaluate this concept.     

超顺磁性氧化铁在肝脏局灶性病变中的定性研究

目的 探讨超顺磁性氧化铁（SPIO）增强MRI在肝脏局灶性病变的定性能力。材料与方法 43例怀疑肝占位者经常规MRI和Gd-DTPA增强后1－7后,行SPIO增强检查。其中31例经手术病理证实,12例经随访、实验室生化检查及临床资料证实。分析平扫MRI及SPIO增强后病灶的信号变化,并与Gd-DTPA动态增强结果相对照。结果 43例共12种病变、单发病灶21例,多病灶22例。包括原发性肝细胞肝癌22例,血管瘤5例,囊肿4例,转移性肝癌5例,肝硬化结节4例,局灶性结节增生（FNH）5例,其他病变6例。22例多发病灶中有8例合并1或2种病变。SPIO增强后,肝细胞肝癌T1WI为等或略高信号,T2WI为较高信号;血管瘤T1WI为较高信号,T2WI信号同平扫为高信号;囊肿T1WI、T2WI信号无改变;肝硬化结节T2WI为等信号同正常肝实质;FNH T2WI信号明显下降。其余病变的诊断SPIO增强不具有特征性,须与Gd-DTPA动态增强相结合。结论 SPIO具有一定的定性能力Gd-DTPA增强相结合,可帮助提高肝局灶性病变诊断和鉴别诊断的准确性。     

肝脏不典型腺瘤样增生结节的综合影像诊断

研究肝脏不典型腺瘤样增生结节的ＵＳ、ＣＴ和ＭＲＩ表现与诊断。方法回顾性分析经病理证实的７例（手术切除３例,ＵＳ引导下肝穿刺活检４例）肝脏不典型腺瘤样增生结节的ＵＳ、ＣＴ和ＭＲＩ表现,以及术前或穿刺前诊断情况,并与病理对照。结果５例诊断为癌前病变,２例误诊为小肝癌。ＵＳ显示稍低或等回声６例,稍强回声１例。     

Characterization of focal hepatic lesions with ferumoxides-enhanced MR imaging: utility of T1-weighted spoiled gradient recalled echo images using different echo times

PURPOSE: To evaluate the different signal characteristics of focal hepatic lesions on ferumoxides-enhanced MR imaging, including T1-weighted spoiled gradient recalled echo (GRE) images using different echo times (TE) and T2- and T2*-weighted images. MATERIALS AND METHODS: Ferumoxides-enhanced MR imaging was performed using a 1.5-T system in 46 patients who were referred for evaluation of known or suspected hepatic malignancies. One hundred and seven lesions (42 hepatocellular carcinomas [HCC], 40 metastases, 13 cysts, eight hemangiomas, three focal nodular hyperplasias [FNHs], and one cholangiocarcinoma) were evaluated. Postcontrast MR imaging included 1) T2-weighted FSE; 2) T2*-weighted GRE; 3) T1-weighted spoiled GRE using moderate (TE = 4.2-4.4 msec) TE; and 4) minimum (TE = 1.8-2.1 msec) TE. Signal intensities of the focal lesions were rated by two radiologists in conference as follows: hypointense, isointense or invisible, hyperintense, and markedly hyperintense. Lesion-to-liver contrast-to-noise ratio (C/N) was measured by one radiologist for a quantitative assessment. RESULTS: On ferumoxides-enhanced FSE images, 92% of cysts were "markedly hyperintense" and most of the other lesions were "hyperintense", and the mean C/N of cysts was significantly higher than that of other focal lesions. T2*-weighted GRE images showed most lesions with similar hyperintensities and the mean C/N was not significantly different between any two types of lesion. T1-weighted GRE images using moderate TE showed all FNHsand hemangiomas, 29 (69%) HCCs and eight (20%) metastases as "hyperintense". On T1-weighted GRE images using minimum TE, however, all HCCs and metastasis except one were iso- or hypointense, while all of the FNHs and hemangiomas were hyperintense. Ring enhancement was highly suggestive of malignant lesions, and was more commonly seen on the minimum TE images than on the moderate TE images. CONCLUSION: Addition of T1-weighted GRE images using minimum and moderate TE is helpful for characterizing focal lesions in ferumoxides-enhanced MR imaging.     

肝脏局灶性结节增生的MRI与病理对照性分析

目的:研究肝脏局灶性结节增生(FNH)的MRI表现和病理学表现及其它们的相关性。方法:回顾性分析9例经手术病理证实的FNH的MRI表现及其病理学表现。结果:FNH平扫T1WI 5例为等信号,4例为稍低信号;T2WI 3例为等信号,6例为稍高信号。7例病灶中心或偏心有瘢痕。动态增强扫描9例病灶在动脉期均呈明显均匀强化;门脉期和延迟期为轻度增强或等信号;7例病灶在延迟期出现瘢痕强化。FNH是多血供实质性肿块,肿瘤内部结构均匀,出血和坏死少见,镜下可见典型的星状瘢痕。结论:MRI平扫和动态增强扫描能够显示FNH的特征性表现,反映FNH的病理特点,提高FNH的确诊率。     

MR of leptomeningeal melanosis in children

Purpose: To delineate the magnetic resonance (MR) appearance of leptomeningeal melanosis in children. Method: Retrospective review of the medical, surgical, pathologic and MR findings in four children with a confirmed histologic diagnosis of leptomeningeal melanosis. The brain MR was performed with Tl- and T2-weighted images in all four children and three had T1-weighted post-gadolinium images. Two of the children also had T1-weighted post gadolinium spine images. Results: The MR brain findings consisted of cortical plaque and nodular hyperintense lesions on the noncontrast T1-weighted images in one child, marked, diffuse leptomeningeal enhancement in two children, and an enlarged, hypointense left temporal lobe with adjacent mild leptomeningeal enhancement in one child. The MR spine findings consisted of diffuse leptomeningeal enhancement in one child and hyperintensity of the cerebrospinal fluid in the other. Conclusion: The T1-weighted pre- and post-contrast images were the best to demonstrate the MR findings in leptomeningeal melanosis which consisted of either diffuse or localized enhancement of the leptomeninges; or cortical plaque and nodular hyperintense lesions pre-contrast.     

MR findings in eosinophilic infiltration of the liver

OBJECTIVE: This study describes the findings of magnetic resonance imaging (MRI) of focal eosinophilic infiltration of the liver. METHODS: Contrast-enhanced MR images of 8 patients with focal hepatic eosinophilic infiltration were reviewed retrospectively. We evaluated the signal intensity of focal lesions in T1-weighted and T2-weighted images and the pattern of enhancement in a dynamic contrast study. RESULTS: A total 22 focal hepatic lesions were observed; the lesions were isointense (55%) or hypointense (45%) on T1-weighted images and isointense (14%) or hyperintense (86%) on T2-weighted images. The arterial phase of the contrast study revealed 11 hyperintense lesions (50%). During the portal and delayed phases, 18 (82%) and 17 lesions (77%) were hyperintense, respectively. CONCLUSION: The focal eosinophilic infiltrations showed homogeneous enhancement in the portal and delayed phases in the dynamic contrast MR study. These findings should help to distinguish focal eosinophilic infiltration, especially from metastasis in patients with malignancy.     

Telangiectatic focal nodular hyperplasia: US,CT, and MR imaging findings with histopathologic correlation in 13 cases

PURPOSE: To review the ultrasonographic (US), computed tomographic (CT), and magnetic resonance (MR) imaging findings in 13 patients with telangiectatic focal nodular hyperplasia (FNH) and to compare imaging features with histopathologic results from resected specimens. MATERIALS AND METHODS: US, helical multiphasic CT, and MR images in 13 patients with pathologically proven telangiectatic FNH were reviewed retrospectively. Two abdominal radiologists evaluated lesions for number, size, heterogeneity, surface characteristics, presence of a central scar, presence of a pseudocapsule, US appearance, attenuation at CT, signal intensity at MR imaging, and presence of associated lesions. Imaging and pathologic findings were compared. RESULTS: Sixty-one lesions (5-140 mm in diameter) were seen at imaging. Lesions were multiple in eight of 13 (62%) patients. Imaging characteristics were heterogeneity in 26 of 61 lesions (43%), well-defined margins in 43 of 61 (70%), lack of a central scar in 56 of 61 (92%), presence of a pseudocapsule in three of 61 (5%), hyperintensity on T1-weighted MR images in 17 of 32 (53%), strong hyperintensity on T2-weighted MR images in 24 of 54 (44%), and persistent enhancement on delayed contrast material-enhanced CT or T1-weighted MR images in 23 of 38 (61%). No specific US pattern was noted. Two patients had additional lesions: One had classic FNH, and the other had a cavernous hemangioma. Hyperintensity on T1-weighted MR images was due to sinusoidal dilatation. Hyperintensity on T2-weighted MR images correlated well with the presence of inflammation. CONCLUSION: Telangiectatic FNH differs from typical FNH at imaging: Atypical FNH features often observed with telangiectatic FNH are lack of a central scar, lesion heterogeneity, hyperintensity on T1-weighted MR images, strong hyperintensity on T2-weighted MR images, and persistent contrast enhancement on delayed contrast-enhanced CT or T1-weighted MR images.     

MRI findings of uterine lipoleiomyoma correlated with pathologic findings

OBJECTIVE: Our objective was to describe the MRI findings of uterine lipoleiomyoma and to correlate them with histopathologic findings. CONCLUSION: Uterine lipoleiomyoma typically presents as a well-demarcated mass showing hyperintensity with hypointense amorphous bundles on T1- and T2-weighted images with chemical shift artifacts. The hyperintense region suppressed on chemical shift fat-suppressed sequences and the hypointense bundles enhanced by contrast material pathologically correspond to mature fat tissue and smooth muscle tissue, respectively. Even in an atypical case with a small volume of fat tissue in the mass, a fat-suppression MRI sequence is especially useful for the diagnosis.     

Liver adenomatosis: classification of MR imaging features and comparison with pathologic findings

PURPOSE: To retrospectively compare the clinical manifestation and magnetic resonance (MR) imaging features of liver adenomatosis with pathologic findings. MATERIALS AND METHODS: This study had institutional review board approval, and informed consent was waived. Twenty patients were classified on the basis of pathologic findings into three groups: those with a steatotic, those with a peliotic, and those with a mixed (steatotic and peliotic) form of liver adenomatosis. MR images were reviewed in consensus by two abdominal radiologists, and findings were compared with the pathologic classification. Statistical evaluation was performed with the Student t test. RESULTS: All patients were women (mean age, 39 years +/- 10 [standard deviation]). Lesions of the steatotic form (n = 7) showed (a) a mean diameter of 6.3 cm +/- 1.7, (b) slightly hyperintense signal on T2-weighted images, (c) hyper- or isointense signal on T1-weighted images with a signal dropout with fat suppression sequences, and (d) moderate enhancement at the arterial phase with no delayed enhancement. Lesions of the peliotic form (n = 7) showed (a) a somewhat larger size (8.3 cm +/- 3.6), (b) markedly hyperintense signal on T2-weighted images, (c) iso- or hyperintensity on T1-weighted images with no signal dropout with fat suppression sequences, and (d) strong arterial enhancement and persistent enhancement at the portal and delayed phase. Lesions of the mixed form (n = 6) included a combination of imaging features of the steatotic and peliotic forms. Lesions, however, were significantly larger in the mixed form than in the steatotic form (10.3 cm +/- 4, P < .05). CONCLUSION: There are three patterns of MR imaging features of liver adenomatosis that are associated with three pathologic forms (steatotic, peliotic, and mixed).