MR of cerebral aspergillosis in patients who have had bone marrow transplantation.

PURPOSETo assess the CT and MR appearance of cerebral aspergillosis in patients who have undergone bone marrow transplantation.METHODSThe imaging and clinical data of five patients with cerebral aspergillosis were reviewed retrospectively and compared with autopsy findings.RESULTSLesions are often located in the basal ganglia and demonstrate an intermediate signal intensity within surrounding high-signal areas on long-repetition-time MR scans. The lesions were multiple in four of the five patients and more numerous on MR images than on CT scans. The lesions (which demonstrate no parenchymal enhancement) are consistent with acute infarcts as confirmed at autopsy. In the large lesions, there is early intravascular and meningeal enhancement, as expected in acute infarcts involving an appreciable portion of the territory of a cerebral artery.CONCLUSIONThe diagnosis of early cerebral infarction in a patient considered at risk for invasive aspergillosis, even without overt pulmonary disease, is an indication to institute aggressive antifungal therapy.     

Solid organizing hepatic abscesses mimic hepatic tumor: Multiphasic computed tomography and magnetic resonance imaging findings with histopathologic correlation

OBJECTIVE: To describe the computed tomography (CT) and magnetic resonance imaging (MRI) findings of solid organizing hepatic abscesses and correlate them with the pathologic findings. METHODS: Ten patients with 10 pathologically proven solid organizing hepatic abscesses who underwent 3-phase CT (n = 10) or MRI (n = 7) were enrolled in this study. Images were retrospectively analyzed by consensus of 2 radiologists for attenuation (signal intensity), shape, and margin of the lesions as well as for their enhancement patterns. Their imaging findings were correlated with their pathologic findings. RESULTS: The main imaging finding on CT or MRI was the well-defined target appearance of a central enhancing area with a low-attenuation (signal intensity) rim on arterial and portal phases. On the delayed phase, most of lesions showed slightly low attenuation (signal intensity) with an enhancing rim, and 1 showed diffuse enhancement. Pathologically, the central areas and peripheral rims corresponded to granulation tissue and fibrosis, respectively. Nine lesions demonstrated a tiny necrotic cystic portion in the center. CONCLUSION: The target appearance of solid organizing hepatic abscesses on CT and MRI can be helpful in differentiating them from other focal liver lesions. These imaging findings are well correlated with the pathologic findings.     

颅内原发恶性淋巴瘤的MRI诊断(附12例报告)

目的　探讨颅内原发恶性淋巴瘤CT及MR的表现特征 ,以提高诊断准确率。方法　对 12例经手术病理证实的颅内原发恶性淋巴瘤的CT及MR表现进行回顾分析。结果　共检出 3 2个病灶 ,其中单发 9例 ,分别位于额、颞、顶叶深部脑白质 8例 ,位于颞叶表面 1例 ;多发 3例 ,病灶多位于深部脑白质。CT多表现为圆形或类圆形稍高密度灶 ,MRI表现为T1WI低或等信号 ,T2 WI为稍低信号。多数病灶周围有轻 -中度高信号水肿带 ,病灶边界尚清楚。增强扫描见所有病灶均有强化 ,2 3个 ( 72 .0 % )病灶呈均匀强化 ,18个 ( 5 6.2 5 % )病灶强化后出现缺口或凹陷改变。病理结果 :11例为非何杰金氏淋巴瘤 ,1例为浆细胞淋巴瘤。结论　尽管颅内原发恶性淋巴瘤的影像表现与其它颅内肿瘤如脑膜瘤、胶质瘤及转移瘤等有许多相似之处 ,但通过认真分析其影像特征 ,术前的正确诊断是有可能的     

眶壁转移瘤的CT和MRI诊断

目的分析研究眶壁转移瘤的CT和MRI特点,提高诊断准确率.方法回顾性分析23例经手术病理证实的眶壁转移瘤的CT和MRI表现,成人组16例,儿童组7例.所有病例均行CT平扫与MR平扫和增强扫描.结果16例成年患者CT表现均为溶骨性骨质破坏和眼眶不规则肿块,9例骨质破坏区邻近的颅内可见扁平不规则肿块;16例MRI表现为骨质破坏区邻近的眼眶和颅内均可见略长T1、略长T2信号的不规则软组织影,增强后呈明显强化.7例儿童患者CT表现均为溶骨性骨质破坏和眼眶不规则肿块,其中2例可见垂直针状高密度影,3例骨质破坏区邻近的颅内可见扁平不规则软组织肿块;MRI显示7例骨质破坏区邻近的眼眶内和6例颅内可见略长T1、略长T2信号不规则的软组织影,其中1例为双侧,增强后呈明显强化;7例双侧眶骨、4例斜坡和双侧岩尖及1例双侧颞骨鳞部骨髓腔呈略长T1、略长T2信号影,增强后呈明显强化.结论眶壁转移瘤的CT和MRI表现有一些特点,有助于诊断和鉴别诊断.     

MR imaging of intracranial tuberculomas

Eight patients with intracranial tuberculomas were studied with CT and magnetic resonance (MR) imaging. Large, ring enhancing, solid lesions on CT showed low intensity on T2-weighted images and intermediate intensity on T1-weighted images. Small lesions, with ring enhancement on CT, showed central bright signal on T2-weighted images with a peripheral low intensity rim surrounded by high intensity edema. The MR imaging features of the tuberculomas were found to be distinct from those of abscesses, metastases, and gliomas.     

Acinic cell carcinoma of the head and neck: radiologic-pathologic correlation

OBJECTIVE: To describe and correlate the imaging and pathologic findings of acinic cell carcinoma (ACC) in the head and neck. METHODS: We reviewed the radiologic findings of 12 patients with pathologically proven ACC in the head and neck. They were 6 males and 6 females (ages: 5-75 years, mean 36 years) who undergoing computed tomography (CT, n=9) and CT with magnetic resonance (MR) imaging (n=3). RESULTS: The lesions in the superficial lobe of the parotid gland were solid (n=7), cystic (n=1), and cystic mass with mural nodule (n=1) on CT. A parapharyngeal lesion was cystic mass with mural nodule, and a submandibular and a palate tumor were cystic lesions on CT. All solid masses in the parotid gland (n=7) included focal low-attenuating portions on CT, which were microcyst, hemorrhage, or necrosis on pathologic examination. We could not find intratumoral calcifications or metastatic lymphadenopathy on imaging and histologic studies in all 12 cases. Internal hemorrhage on the MR images was seen in a parapharyngeal and a parotid lesion. CONCLUSION: Although ACC appears to have nonspecific imaging findings, familiarity with some imaging features can be helpful for differential diagnosis of head and neck tumors.     

Abnormal ocular enhancement in Sturge-Weber syndrome: correlation of ocular MR and CT findings with clinical and intracranial imaging findings.

PURPOSETo estimate the prevalence of abnormal ocular enhancement in children with Sturge-Weber syndrome as detected with MR imaging and CT and to correlate this with the clinical, fundoscopic, and intracranial imaging findings.METHODSFifteen children, 4 years old or younger, with Sturge-Weber syndrome were examined with enhanced CT and MR imaging. Eleven children had unilateral intracranial involvement and 4 had bilateral involvement, for a total of 19 abnormal hemispheres and related orbits. The presence of ocular enhancement was compared with the fundoscopic findings independently. Ocular enhancement was correlated with the extent of leptomeningeal disease, the severity of the cutaneous lesion, and the presence of glaucoma by the calculation of likelihood ratios and 95% confidence limits.RESULTSSeven of the 15 patients had abnormal ocular enhancement, which was present in 10 (53%) of the eyes associated with the 19 abnormal hemispheres. MR imaging showed choroidal hemangioma in 7 of 8 patients in whom hemangiomas were shown at fundoscopy. The likelihood of ocular enhancement was increased with the presence of bilateral disease, extensive facial nevi, and glaucoma; there was no significant correlation with the extent of hemispheric involvement.CONCLUSIONBoth enhanced MR imaging and CT can show diffuse choroidal hemangioma in patients with Sturge-Weber syndrome. However, MR imaging is more sensitive and is recommended to aid in the detection of abnormalities with preventable late complications.     

AIDS-related CNS cryptococcosis: radiologic-pathologic correlation.

PURPOSE: This study evaluates the effectiveness of cranial CT and MR in detecting autopsy findings of AIDS-related CNS cryptococcosis. METHODS: Final imaging studies compared with pathology were CT in eight patients (five with contrast) and MR in five patients (all with Gd-DTPA). RESULTS: Neither modality effectively identified cryptococcal meningitis. Punctate hyperintensities were seen in all patients with MR and corresponded pathologically to both perivascular spaces dilated by cryptococcal infection and cryptococcomas. Pathologically, cryptococcomas were more common than dilated perivascular spaces. MR detected more cryptococcomas than did CT, but both modalities underestimated the number of lesions seen at autopsy. Contrast enhancement of cryptococcomas and cryptococcal meningitis was uncommon. CONCLUSIONS: CNS cryptococcosis was more effectively demonstrated by MR than by CT, but both modalities underestimated the pathologic extent of the disease. Cryptococcal lesion contrast enhancement was unusual possibly because of the immunocompromised state of our patients and the unique characteristics of the organism itself.     

Intracranial aspergillosis involving the internal auditory canal and inner ear in an immunocompetent patient

We report the MR imaging findings in a case of intracranial aspergillosis involving the internal auditory canal (IAC) and inner ear in an immunocompetent patient. The presence of rim enhancement of the vestibulocochlear nerve, abnormal signal intensity involving the labyrinth, and adjacent meningeal enhancement might help clinicians to make a correct diagnosis in patients with a mass in the IAC and previous history of ear surgery.     

幕上原始神经外胚层肿瘤的影像学表现

目的 研究幕上原始神经外胚层肿瘤的影像表现。方法 经手术与病理证实的7例幕上原始神经胚层肿瘤患者均经MRI检查，6例又经CT扫描。所有患者的MRI与CT表现是与手术病理对照分析的。结果 肿瘤病变的部位包括额叶2例，顶叶、胼胝体、侧脑室、松果体、顶枕叶各1例。7例肿瘤均呈囊实性肿块，边界清楚，体积较大，常伴囊变或出血。肿瘤的实性部分在T1WI上呈等或稍低信号，在T2WI上呈稍高信号，增强扫描均明显强化。CT平扫肿瘤常呈等或稍低密度，水肿较轻，增强扫描后明显强化。结论 幕上原始神经外胚层肿瘤的影像学表现有一定的特征性，但确诊需结合病理和免疫组织化学检查。     

Detection of acute and treated lesions of hepatosplenic candidiasis: comparison of dynamic contrast-enhanced CT and MR imaging.

Dynamic contrast-enhanced computed tomography (CT) was compared with 1.5-T magnetic resonance (MR) imaging with FLASH (fast low-angle shot), gadolinium-enhanced FLASH (Gd-FLASH), and T2-weighted fat-suppression (T2FS) sequences in 11 patients with hematologic malignancies, five with biopsy-confirmed hepatosplenic candidiasis treated with antifungal chemotherapy and six with a clinical history suggestive of acute hepatosplenic candidiasis. CT and MR images were separately interpreted in a prospective fashion. MR imaging showed lesions compatible with candidiasis in the liver in six patients, the spleen in five, and the kidneys in one. CT showed candidiasis-compatible lesions in the liver in three patients and the spleen in one; no renal lesions were shown. Differences between acute and treated candidal lesions were observed. Gd-FLASH images showed the most liver lesions (n = 106), followed by FLASH (n = 85), T2FS (n = 20), and CT (n = 18). MR imaging performed better than CT in distinguishing candidal hepatic lesions from recurrent lymphoblastic lymphoma in one patient and from hepatic infarcts in another. The results suggest that MR imaging may be superior to CT in detecting lesions of hepatosplenic candidiasis.     

The variable MR appearance of primary lymphoma of the central nervous system: comparison with histopathologic features.

PURPOSETo describe the MR features of primary central nervous system (CNS) lymphoma and to determine whether there is a correlation with histopathologic findings.METHODSThe MR images, pathologic specimens, and clinical records of 23 patients with primary CNS lymphoma were reviewed. The imaging and pathologic characteristics were tabulated and compared by using the standard tests for association in a two-dimensional contingency table.RESULTSA total of 61 lesions were present in 23 patients; 12 patients (52%) had multiple lesions. All lesions were isointense or hypointense on T1-weighted images, and 53% were isointense or hypointense on T2-weighted images. Twenty patients received intravenous contrast material, and 43 (91%) of 47 lesions enhanced. The three patients who had nonenhancing lesions received steroids before the initial MR studies. Enhancement patterns differed between the immunocompetent and the immunocompromised hosts, with the latter group harboring a higher percentage of rim-enhancing lesions. Twenty-seven (44%) of the lesions were centered in a cerebral hemisphere and 14 (23%) were centered in the central gray matter. There was a statistically significant correlation between a higher degree of necrosis histologically and hyperintensity on T2-weighted MR images. The degree of necrosis also showed a positive correlation with rim enhancement.CONCLUSIONSPrimary CNS lymphoma has a variable MR appearance that correlates with the severity of intratumoral necrosis. These imaging characteristics, as well as lesion location, mean lesion size, and proclivity to harbor necrosis, are altered in the immunocompromised host.     

Pediatric choroid plexus neoplasms: MR, CT, and pathologic correlation

Choroid plexus papillomas are rare, constituting approximately 0.5% of all intracranial neoplasms. Four benign choroid plexus papillomas and one choroid plexus carcinoma were retrospectively reviewed in patients aged 4-20 months who had been examined with magnetic resonance (MR) imaging with a field strength of 0.5 T or 1.0 T and with computed tomography (CT) before and after the administration of contrast material. In general, the tumors were of intermediate signal intensity on T1-weighted images and of either intermediate or increased signal intensity (T2 lengthening) with T2 weighting. All demonstrated variable areas of internal signal void interpreted as signifying regional blood flow, calcification, or old hemorrhage. CT findings included relatively uniform contrast enhancement. Microscopic pathologic changes of the benign lesions mimicked the appearance of normal choroid plexus and confirmed the highly vascular nature of these tumors. MR imaging, with its high-resolution multiplanar techniques, offers direct visualization of these lesions in relation to normal anatomy and better discrimination and confirmation of their intraventricular location, facilitating surgery and postoperative follow-up.     

Wegener granulomatosis: MR imaging findings in brain and meninges

PURPOSE: To determine the spectrum of intracranial magnetic resonance (MR) imaging appearances of Wegener granulomatosis. MATERIALS AND METHODS: MR imaging studies in 19 patients with Wegener granulomatosis and possible central nervous system involvement were reviewed by two neuroradiologists. Intermediate-weighted and T2-weighted fast spin-echo MR images of the brain had been acquired in all patients, and spin-echo T1-weighted nonenhanced and gadolinium-enhanced images had been acquired in 18 patients. RESULTS: MR imaging findings included diffuse linear dural thickening and enhancement (n = 6); focal dural thickening and enhancement contiguous with orbital, nasal, or paranasal disease (n = 5); infarcts (n = 4); nonspecific white matter areas of high signal intensity on intermediate-weighted and T2-weighted images (n = 10); enlarged pituitary gland with infundibular thickening and enhancement (n = 2); a discrete cerebellar lesion that was probably granulomatous in origin (n = 1); and cerebral (n = 8) and cerebellar atrophy (n = 2). CONCLUSION: MR imaging demonstrated the wide spectrum of findings of central nervous system involvement in patients with Wegener granulomatosis and was particularly useful for the evaluation of direct intracranial spread from orbital, nasal, or paranasal disease.     

颅内磁共振成像(MRI)环形强化病变

目的　对照研究颅内常见MRI环形强化病变的MR影像表现 ,分析常见病变的影像学特点。方法　回顾性分析了 65例颅内常见MRI环形强化病变的临床及MR影像资料。其中胶质母细胞瘤 17例 ,转移瘤 17例 ,脑脓肿 12例 ,听神经鞘瘤 8例 ,颅咽管瘤 7例 ,脑囊虫 3例 ,原发性恶性淋巴瘤 1例。全部病例均经手术、病理证实。结果　肿瘤性病变的环形强化表现为厚壁 ,且壁厚薄不均、形态不规整 ,其中高度恶性肿瘤的强化环明显厚薄不均一 ,尤其是内壁凹凸不平、毛糙不光滑。非肿瘤性病变的强化环通常表现为形态规整 ,厚薄较为均匀一致 ,内壁光滑。结论　颅内常见MRI环形强化病变的不同表现形式可以为诊断提供重要信息 ,同时结合病人的病史、年龄、部位以及MR平扫的影像表现 ,在大多数情况下是可以做出正确诊断的     

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.     

颅内生殖细胞瘤的CT和MRI表现

目的探讨颅内生殖细胞瘤的CT和MRI表现。方法经手术病理及放疗证实的颅内生殖细胞瘤19例,回顾性分析其治疗前CT和MRI图像。结果19例肿瘤中,12例位于松果体区,3例位于基底节区及丘脑,4例位于鞍区。松果体区肿瘤MRI呈长T1、等或长T2信号,边缘光滑,出血少见,CT呈均匀等密度或稍高密度,松果体钙化常被肿瘤包埋,增强呈均匀显著强化。鞍区肿瘤垂体柄增粗,垂体后叶正常短T1信号消失,肿瘤T1WI呈等信号,T2WI上信号可以表现为等或高信号,CT上肿瘤实体部分呈高密度,增强扫描有明显强化。基底节及丘脑肿瘤,呈弥漫性生长,瘤体较大,信号及密度不均匀,边缘欠清晰,出血多见,增强呈斑片或花环样强化。结论颅内生殖细胞瘤,根据发生性别、年龄和MR及CT影像表现具有一定特点,在多数情况下可做出术前诊断。     

原发性脑淋巴瘤的影像诊断

目的分析免疫功能正常患者原发性脑淋巴瘤影像诊断。方法回顾性分析5例免疫功能正常,经病理证实的原发性脑淋巴瘤CT、MR和PET所见。结果肿瘤可发生于幕上或幕下,可单发或多发。CT扫描多表现为等密度或稍高密度肿块,T     

颅内胚胎发育不良性神经上皮瘤影像与病理

目的探讨颅内胚胎发育不良性神经上皮瘤(DNT)的影像表现,以期提高诊断水平。方法回顾分析13例经手术和病理证实的颅内胚胎发育不良性神经上皮瘤的影像表现,并与手术病理相对照。全部病例行MRI平扫与增强扫描,其中6例行CT平扫,3例行18F-FDG正电子发射体层摄影(PET)检查。结果颞叶8例,额叶3例,顶叶及四脑室底各1例,病变位于皮层及皮层下区。MRI平扫呈均匀或不均匀长T1、长T2信号,增强扫描12例无明显强化,1例仅见结节状强化。CT平扫4例呈均匀低密度,2例呈低、等混杂密度;PET检查3例均呈低代谢改变。结论颅内胚胎发育不良性神经上皮瘤的影像表现有一定特点,综合影像学检查有助于该病的诊断。     

Hepatic Cavernous Hemangioma in Cirrhotic Liver: Imaging Findings

Objective

To document the imaging findings of hepatic cavernous hemangioma detected in cirrhotic liver.

Materials and Methods

The imaging findings of 14 hepatic cavernous hemangiomas in ten patients with liver cirrhosis were retrospectively analyzed. A diagnosis of hepatic cavernous hemangioma was based on the findings of two or more of the following imaging studies: MR, including contrast-enhanced dynamic imaging (n = 10), dynamic CT (n = 4), hepatic arteriography (n = 9), and US (n = 10).

Results

The mean size of the 14 hepatic hemangiomas was 0.9 (range, 0.5-1.5) cm in the longest dimension. In 11 of these (79%), contrast-enhanced dynamic CT and MR imaging showed rapid contrast enhancement of the entire lesion during the early phase, and hepatic arteriography revealed globular enhancement and rapid filling-in. On contrast-enhanced MR images, three lesions (21%) showed partial enhancement until the 5-min delayed phases. US indicated that while three slowly enhancing lesions were homogeneously hyperechoic, 9 (82%) of 11 showing rapid enhancement were not delineated.

Conclusion

The majority of hepatic cavernous hemangiomas detected in cirrhotic liver are small in size, and in many, hepatic arteriography and/or contrast-enhanced dynamic CT and MR imaging demonstrates rapid enhancement. US, however, fails to distinguish a lesion of this kind from its cirrhotic background.