Musculoskeletal haemangiomas: comparison of MRI with CT

MRI and CT findings were reviewed from 11 patients with musculoskeletal haemangiomas. With MRI, morphological characteristics and extent of haemangiomas were optimally demonstrated on T₂-weighted spin echo scans. High-resolution contrast-enhanced CT provided equivalent information regarding lesional characteristics and extent for small, localized haemangiomas. In CT evaluation of the extent of large haemangiomas, the radiation dose, transaxial scan plane, amount of intravenous contrast medium required and the necessity for correct timing of post-contrast scans became limiting factors. For such lesions, particularly those extending into the trunk, MRI supplemented by a plain radiograph is the optimum method of evaluation.     

Generalized intramuscular granulocytic sarcoma mimicking polymyositis

We report a case of granulocytic sarcoma exclusively manifesting as diffuse intramuscular infiltration of the proximal upper and lower limb girdle and the torso muscles in a patient with previous history of acute myelogenous leukemia 5a. Whole-body CT showed widespread distribution of ill-defined intramuscular, homogeneously enhancing lesions. On whole-body MRI, lesions were homogeneously hyperintense on fat saturated T2-weighted images, isointense on T1-weighted images and strongly enhancing after intravenous gadolinium contrast administration. Histopathology revealed muscular infiltration of blast cells with identical immunochemistry to the initial manifestation of leukemia, diagnostic for an extramedullary relapse manifesting as granulocytic sarcoma. CT and MRI characteristics of this previously undocumented manifestation of granulocytic sarcoma should assist in the identification of such cases.     

Adrenal phaeochromocytoma: correlation of MRI appearances with histology and function

The purpose of this study was to describe the range of appearances of adrenal phaeochromocytomas on T2-weighted MRI, correlate appearances with histopathology, and quantify the incidence of the previously described hyperintense appearance. The appearance and MR characteristics of 44 phaeochromocytomas were reviewed retrospectively. T2-weighted appearances were grouped: (1) ‘classical’, homogeneous, high signal intensity, isointense to CSF; (2) homogeneous, isointense or minimally hyperintense to spleen, hypointense to CSF; (3) heterogeneous, marbled appearance; (4) heterogeneous, multiple high signal intensity pockets. All 44 adrenal phaeochromocytomas were well circumscribed, 1.2–15 cm in maximum diameter, with no visual or quantitative signal loss on chemical shift imaging. On T2-weighted MRI 5/44 (11%) had group 1 appearance; 15/44 (34%) group 2, 7/44 (16%) group 3; and 17/44 (39%) group 4. Homogeneous group 1 and 2 lesions were smaller (mean 4.5 cm) than heterogeneous group 3 and 4 lesions (mean 6.3 cm). Increasing MRI heterogeneity correlated pathologically with increasing amounts of haemorrhage, necrosis and fibrosis. No MRI features were predictive of malignancy. Non-functioning phaeochromocytomas were larger than functioning lesions. No size difference was seen between syndrome and sporadic lesions. In this large series we report a wide range of appearances of adrenal phaeochromocytomas on T2-weighted MRI. The previously described classical hyperintense phaeochromocytoma is relatively uncommon.     

MRI findings in cerebral fat embolism

The purpose of this retrospective study was to demonstrate the MRI features of cerebral manifestations in patients with fat embolism syndromes in comparison with cerebral CT (CCT). Magnetic resonance imaging was performed according to standard protocols revealing multiple small non-confluent hyperintense intracerebral lesions larger than 2 mm on proton-density and T2-weighted images to various extents in three of four patients with clinically suspected cerebral fat embolism. Cerebral CT was negative in all patients. Our findings confirm that MRI can detect cerebral fat embolism with a higher sensitivity than CCT. Thus, MRI should be the first choice for imaging of cerebral fat embolism. Received 28 November 1997; Revision received 9 March 1998; Accepted 30 March 1998     

A possible cause of multiple intramuscular masses: Mazabraud’s syndrome (2007: 11b)

Mazabraud’s syndrome is the association of fibrous bone dysplasia and myxomas in soft tissues. We present a new case of this condition in a 52-year-old female patient who presented with pain in the epigastric region. As an incidental finding an abdominal CT showed multiple hypodense intramuscular masses in the upper third of her left thigh associated with a bone lesion in the left femur and left ischiopubic ramus. A plain X-ray showed bone damage in those two bones with a ground-glass pattern and gross trabeculation, consistent with fibrous bone dysplasia. The MRI showed multiple intramuscular masses hypointense in T1-weighted images and hyperintense in T2-weighted images with contrast peripheral enhancement after administering an intravenous contrast agent, with the exception of one of the masses, which showed central enhancement, suggesting multiple myxomas. Very few conditions exist that present as multiple intramuscular masses. The association of multiple intramuscular myxomas and fibrous bone dysplasia should raise suspicion of the presence of this syndrome, and allows for the follow-up of lesions, preventing unnecessary biopsies. The objective of this report is to describe a new case.     

MR and CT appearance of nodular fasciitis

Nodular fasciitis is a common soft-tissue tumor that remains almost unreported in the radiology literature. We retrospectively reviewed all available imaging studies on three patients with nodular fasciitis studied by MR at our institution. The lesions were round to oval in configuration, ranging in size from 1 to 4.5 cm. Two were intramuscular and one was subcutaneous in location. Both intramuscular lesions were poorly defined on CT, with a tissue attenuation less than that of skeletal muscle. The single subcutaneous lesion was well defined by surrounding fat. Conversely, all lesions were well defined on MR, although the appearance was otherwise nonspecific and varied according to the histology of the lesion. Both intramuscular lesions were mucoid or cellular and were hyperintense to skeletal muscle on T1-weighted and hyper-intense to fat on T2-weighted spin-echo (SE) MR images. The subcutaneous lesion was fibrous and markedly hypointense to skeletal muscle on all SE pulse sequences. Findings on three-phase bone scan, arteriography, and ultrasound are discussed. Because there are no unique radiologic findings in nodular fasciitis, this entity must be included in the preoperative differential diagnosis of small soft-tissue masses occurring in the extremities of young adults.     

Magnetic resonance imaging appearance of well-differentiated hepatocellular carcinoma

OBJECTIVE: To investigate the magnetic resonance imaging (MRI) features of well-differentiated hepatocellular carcinoma (HCC). METHODS: We reviewed the MRI of 32 patients with 33 pathologically confirmed well-differentiated HCC. The MRI protocol included T2-weighted imaging with and without fat saturation, dual-phase T1-weighted imaging, and gadolinium-enhanced dynamic study. The signal intensity of each lesion was categorized as hyperintense, isointense, and hypointense with reference to the surrounding liver parenchyma. RESULTS: Thirty-one (93.9%) of 33 well-differentiated HCC were demonstrated on the MRI. The remaining 2 were isointense in all magnetic resonance sequences and, therefore, could not be identified. Most of them were hyperintense (n = 15 [45.4%]) or isointense (n = 16 [48.5%]) on T1-weighted imaging, and hyperintense (n = 12 [36.4%]) or isointense (n = 17 [51.5%]) on T2-weighted imaging. On the dynamic study, 17 lesions (51.5%) were enhanced. CONCLUSIONS: MRI may identify most well-differentiated HCC; however, the imaging appearance is diverse. Biopsy should be performed if magnetic resonance study is inconclusive.     

Polyostotische Knochenver?nderungen mit assoziierten intramuskul?ren Weichteiltumoren

A 40-year-old female patient presented with progressive painful soft tissue lesions in the left upper arm. Conventional radiography showed multicystic bone tumors of the left humerus, radius and ulna. The computed tomography (CT) scan showed no paraosteal spread. Magnetic resonance imaging (MRI) detected intramuscular tumors in the deltoid muscle, biceps humeri muscle and triceps humeri muscle which were T2-weighted hyperintense and T1-weighted hypointense. Postcontrast images showed a marginal enhancement. The findings corresponded to the rare Mazabraud’s syndrome in which polyostotic fibrous dysplasia is associated with intramuscular myxomas.     

腹盆部巨大淋巴结增生症的CT及MRI表现和不同病理类型能谱CT特征

目的探讨腹盆部巨大淋巴结增生症(Castleman病)的CT和MRI特征性表现,并对不同病理类型进行能谱CT分析。方法 13例患者均行CT平扫+动态增强检查,启用GSI viewer软件,在动脉期及门静脉期图像上综合观察,然后在动脉期图像上测量相关数据,其中10例患者采用3.0TGE Discovery MRI扫描仪行T1WI、T2WI横轴面及T2脂肪抑制轴位平扫,5例行T1WI动态三期增强。结果 CT平扫9例均呈类圆形等密度肿块,轻度分叶,边缘光滑清晰,4例肿块密度不均并伴有斑点状钙化,动态增强9例均见动脉期显著强化、门静脉期、延迟期持续均匀强化,4例伴有钙化的肿块呈不均匀持续强化,2例肿块周围可见子灶。10例行MRI检查,平扫呈等或稍长T2、长T2信号,T2脂肪抑制呈明显高信号,5例增强后病灶呈中度强化,瘤灶内均可见中央条索状及小片状低信号区。本组病例中均为局限型,7例位于腹膜后,3例位于肠系膜区,3例位于盆腔,其中1例合并左侧卵巢纤维瘤。10例病理类型为透明血管型,3例为浆细胞型。综合混合能量图像、单能量图像及碘基图图像三种图像能使病灶显示更清楚,不同病理类型在不同keV下其衰减程度不同,其能谱曲线图表现不同。在碘基图及水基图上可见10例透明血管型碘含量明显增高,而3例浆细胞型碘含量明显低于透明血管型,但含水量稍高于前者。结论腹盆部Castleman病具有一定特征性,CT动态增强及MRI对透明血管型诊断不难,而浆细胞型Castleman病临床表现复杂,影像学表现不典型,术前诊断仍较困难,需结合病理学检查,但能谱CT分析有助于病理分型。     

Imaging strategies in the evaluation of soft-tissue hemangiomas of the extremities: correlation of the findings of plain radiography,angiography, CT,MRI, and ultrasonography in 12 histologically proven cases

Twelve patients with the histologic diagnosis of soft-tissue hemangioma of the extremities (nine intramuscular, two subcutaneous, and one synovial) were evaluated in a retrospective study using plain film radiography (n = 12), angiography (n = 8), computed tomography (CT; n = 4), magnetic resonance imaging (MRI; n = 3), and ultrasonography (US; n = 2). In eight of nine intramuscular lesions, the plain film demonstration of phleboliths suggested the diagnosis, while the plain radiographs were normal in three. Angiograms showed the pathognomonic features of soft-tissue hemangioma in six patients. MRI was characteristic in all three patients: The lesion demonstrated intermediate signal intensity on T1-weighted spin echo images and extremely bright signal on T2-weighting. US showed a hypoechoic soft-tissue mass in one case and a mixed echo pattern in the other. In one case, a central echogenic focus with acoustic shadowing consistent with a calcified phlebolith was identified, and one lesion exhibited increased color flow and low resistance arterial Doppler signal. CT showed a nonspecific mass in one of four cases and a mass with phleboliths in three. If a deep hemangioma is suspected, we recommend initial imaging with plain radiography followed by MRI. US may be useful in confirming the presence of a mass in doubtful cases or if MRI is unavailable. CT offers no distinct advantage over the combined use of plain radiography and MRI. Although angiography demonstrated the pathognomonic features in all six deeply situated lesions, because of its invasiveness it should be reserved chiefly for those patients undergoing surgical resection.     

MR imaging of gastrointestinal leiomyosarcoma

Two cases of leiomyosarcoma, one in the esophagus and the other in the small intestine, underwent magnetic resonance imaging (MRI). Spin echo T1-weighted images of both leiomyosarcomas showed almost the same intensity as muscle. Spin echo T2-weighted images showed the tumors to be hyperintense compared with fat; however, the esophageal tumor was more hyperintense than the small intestinal one. The jejunal leiomyosarcoma had a central cavity on MRI and CT, suggesting that it was malignant.     

Intramuscular myxoma: characteristic MR imaging features

OBJECTIVE: The purpose of our study was to identify the characteristic MR imaging features of intramuscular myxoma. MATERIALS AND MATERIALS: We retrospectively reviewed the MR imaging features of 20 patients with intramuscular myxoma. Clinical assessment included the age and sex of the patient and location of the tumor. Radiologic evaluation included the lesion size and shape, border definition, signal on T1- and T2-weighted or fluid-sensitive MR sequences, enhancement pattern, presence or absence of a fat rind, and presence or absence of increased signal in the adjacent muscle on T2-weighted or fluid-sensitive MR sequences. RESULTS: The mean age of patients presenting with intramuscular myxoma was 61 years (range, 15-85 years; median, 64 years). The mean lesion size was 6.9 cm (range, 3-17 cm; median, 6.3 cm). A peritumoral fat rind was present in 13 of the patients (65%) with myxoma, and an increased signal in the adjacent muscle on fluid-sensitive sequences was present in 11 patients (55%). Intramuscular myxomas were homogeneously low in signal intensity on T1-weighted MR sequences in 19 patients (95%), with all lesions showing a high signal intensity on T2-weighted or fluid-sensitive MR sequences. Twelve of the myxomas had well-defined borders, and eight had borders that were partially ill defined. Of the 11 lesions imaged after gadolinium administration, six (55%) showed intense heterogeneous enhancement. CONCLUSION: Findings of a mass that on MR images shows a perilesional fat rind, the signal intensity of fluid, and an increased signal in the adjacent muscle on T2-weighted or fluid-sensitive MR sequences are strongly suggestive of intramuscular myxoma. The degree of lesion enhancement varies but is most frequently intense and heterogeneous. Although the recognition of these features likely will not obviate biopsy of any individual lesion, it will allow more accurate prebiopsy diagnosis and preoperative planning.     

Human fascioliasis: MR imaging findings of hepatic lesions

Our objective was to describe MR imaging findings of liver lesions in human fascioliasis. The MR imaging of the liver was performed in 29 patients with fascioliasis. Seventeen patients were women and 12 were men, with a mean age of 47.5 years (age range 17–75 years). Hepatic lesions were grouped into five types based on their signal characteristics. Three patients had normal imaging findings. One or more lesions were observed in the other 26 patients. The lesion types and the frequency of appearances were as follows: hyperintensity of the liver capsule on T2-weighted images (n=16, 55.2%); ill-defined slightly hyperintense areas on T2-weighted images (n=18, 62.1%); lesions which were hypointense on T1-weighted and hyperintense on T2-weighted images (n=10, 34.5%); hypointense on T1-weighted images and centrally hypo- or hyperintense, surrounded by peripherally less hyperintense area on T2-weighted images (n=4, 13.8%); and hypointense foci or ill-defined hypointense areas on T1- and T2-weighted images (n=10, 34.5%). We describe the MR imaging features of the disease. Our findings may help the differential diagnosis in which fascioliasis should be added to the list. Electronic Publication     

Castleman disease of the neck: CT and MR imaging findings

Objective

To characterize the computed tomography (CT) and magnetic resonance imaging (MRI) findings of Castleman disease of the neck.

Methods

The imaging findings of 21 patients with Castleman disease of the neck were reviewed retrospectively. Of the 21 patients, 16 underwent unenhanced and contrast-enhanced CT scans; 5 underwent unenhanced and contrast-enhanced MRI scans.

Results

The unenhanced CT images showed isolated or multiple well-defined homogenous mild hypodensity lesions in fifteen cases, and a heterogeneous nodule with central areas of mild hypodensity in one case. Calcification was not observed in any of the patients. In five patients, MR T1-weighted images revealed well-defined, homogeneous isointense or mild hyperintense lesions to the muscle; T2-weighted images showed these as intermediate hyperintense. Sixteen cases showed intermediate to marked homogeneous enhancement on contrast-enhanced CT or MR T1-weighted images. Of the other five cases that underwent double-phase CT scans, four showed mild or intermediate heterogeneous enhancement at the arterial phase, and homogeneous intermediate or marked enhancement at the venous phase; the remaining case showed mild and intermediate ring-enhancement with a central non-enhanced area at the arterial and venous phases, respectively.

Conclusion

Castleman disease of the neck can be characterized as solitary or multiple well-defined, mild hypodensity or homogeneous intense lesions on plain CT/MR scans, and demonstrates intermediate and marked enhancement on contrast-enhanced CT/MR scans. On double-phase CT scans, Castleman disease often demonstrates mild enhancement at the arterial phase, and gradually uniform enhancement at venous phase. Double-phase enhanced CT or MRI may help to differentiate Castleman disease from other diseases.     

急性骨髓炎的影像学诊断研究进展

急性骨髓炎的影像学诊断技术包括X线平片、超声、CT、MRI及放射性核素显像.早期X线平片的诊断灵敏度低.超声能早期发现深部软组织及骨膜下脓肿,但图像质量取决于操作者的熟练程度.CT能早期观察到微小的骨质改变,但灵敏度较低.MRI可优于其他检查显示髓腔内的病变,但对于死骨、钙化的诊断不如CT灵敏.放射性核素显像剂的种类繁...     

Hyperintense middle cerebral artery sign using MRI

AIM: To assess whether the presence of the hyperintense middle cerebral artery (MCA) sign, detected using magnetic resonance imaging (MRI), has any prognostic value in subacute infarction. The results were also compared with computed tomography (CT). MATERIALS AND METHODS: Twenty-five consecutive patients with suspected subacute ischaemic stroke (6-48 h after onset of symptoms) underwent MRI and CT assessment. The incidence of intraluminal thrombus demonstrated by conventional T1 and T2-weighted images was assessed. The results were correlated with National Institutes of Health Stroke Scale (NIHSS). RESULTS: Hyperintense MCA was identifiable on T1-weighted images in 77.8% patients, on T2-weighted images in 61.1% patients, and in 38.9% patients using CT. Patients with intraluminal thrombus identified by MRI had more severe stroke (mean NIHSS of 12.2+/-8.0 versus 4+/-3.2 respectively, p=0.003). CONCLUSIONS: The presence of hyperintense MCA by MRI is associated with higher NIHSS and may therefore have a prognostic value.     

Imaging of atypical lipomas of the extremities: Report of three cases

Atypical lipomas are soft tissue neoplasms which differ from simple lipomas in that they consist of mature fat cells interspersed with occasional areas containing a variable admixture of multinucleated cells, collagen bundles, and adipocytes with large, hyperchromic nuclei. Although these histopathologic features resemble those of liposarcoma, atypical lipomas occuring in the extremities differ from liposarcoma because they have no tendency for distant metastases. Three patients with atypical lipomas involving the posterior compartment of the thigh are presented. The lipomas were imaged with computed tomography (CT) and magnetic resonance imaging (MRI), using a 0.15-T whole body imager. Although all lesions appeared largely lipomatous, the three lesions simulated liposarcoma on both CT and MRI. On CT, each lesion demonstrated small areas of confluent soft tissue density; these areas were hyperintense with adipose tissue on strongly T2-weighted MRI. We conclude that atypical lipoma of the extremities may not be distinguishable from liposarcoma on imaging and that biopsy is necessary for differentiation.     

Surface-coil MR of orbital pseudotumor

Fifteen patients with clinical presentations compatible with idiopathic inflammatory orbital pseudotumor were examined by CT and MR imaging to determine if MR could add specificity to the CT appearance of this entity. MR was performed on a 1.5 T system, using surface-coil and head-coil techniques. Idiopathic pseudotumor was confirmed in nine patients on the basis of response to steroid therapy in the absence of local cause or systemic illness. One other patient had biopsy-proven idiopathic pseudotumor. Five patients proved to have other orbital entities, including metastases, infectious myositis, hemorrhage, and orbital sarcoid. In all 10 patients with confirmed pseudotumor, CT and MR were abnormal. MR abnormalities in 10 of 10 patients with pseudotumor were hypointense to fat and isointense to muscle on T1-weighted images. On T2-weighted images the lesions of pseudotumor were isointense or only minimally hyperintense to fat in nine of 10 cases; in one case, the enlarged muscle was markedly hyperintense to fat. The MR signal intensity of pseudotumor was similar to that found in infectious myositis and sarcoid. These findings contrasted to the MR appearance of the other disease entities examined. Metastases appeared markedly hyperintense to fat on T2-weighted images, while hematoma was hyperintense to muscle and isointense to fat on T1-weighted images and markedly hyperintense to fat on T2-weighted images. In our preliminary series, surface-coil MR appears to add specificity to the CT appearance of orbital pseudotumor.     

Multifocal nodular fatty infiltration of the liver mimicking metastatic disease on CT: imaging findings and diagnosis using MR imaging

The aim of this study was to describe the MR appearance of multifocal nodular fatty infiltration of the liver (MNFIL) using T1-weighted in-phase (IP) and opposed-phase (OP) gradient-echo as well as T2-weighted turbo-spin-echo sequences with fat suppression (FSTSE) and without (HASTE). Magnetic resonance imaging examinations at 1.5 T using T1-weighted IP and OP-GRE with fast low angle shot (FLASH) technique, and T2-weighted FSTSE, T2-weighted HASTE of 137 patients undergoing evaluation for focal liver lesions were reviewed. Five patients were identified in whom CT indicated metastatic disease; however, no liver malignancy was finally proven. Diagnosis was confirmed by biopsy (n = 3), additional wedge resection (n = 1) or follow-up MRI 6–12 months later (n = 5). Regarding the identified five patients, the number of focal liver lesions was 2 (n = 2) and more than 20 (n = 3). The MR imaging characteristics were as follows: OP-image: markedly hypointense (n = 5); IP image: isointense (n = 2) or slightly hyperintense (n = 3); T2-weighted FSTSE-image: isointense (n = 5); T2-weighted HASTE image isointense (n = 1); slightly hyperintense (n = 4). On OP images all lesions were sharply demarcated and of almost spherical configuration (n = 5). Further evaluation by histology or follow-up MR imaging did not give evidence of malignancy in any case. Histology revealed fatty infiltration of the liver parenchyma in three patients. Magnetic resonance follow-up showed complete resolution in two patients and no change in three patients. Multifocal nodular fatty infiltration can simulate metastatic disease on both CT and MR imaging. The combination of in-phase (IP) and opposed-phase (OP) gradient-echo imaging can reliably differentiate MNFIL from metastatic disease. Received: 15 September 1999 Revised: 3 February 2000; Accepted: 7 February 2000     

Magnetic Resonance Imaging Characteristics of Primary Intraspinal Peripheral Primitive Neuroectodermal Tumour

Purpose

The purpose of our study was to describe the salient magnetic resonance imaging (MRI) findings in primary intraspinal peripheral primitive neuroectodermal tumour (PNET).

Methods

A retrospective review of the clinical and MRI images of 7 pathologically proven cases of intraspinal peripheral PNETs was performed. The various parameters, such as vertebral level of involvement; tumour location, size, focality, and margin; signal intensity of the lesion; the presence of hemorrhage or calcification; any signal voids; assessment of the adjacent cord for cord compression; cord dilatation; the presence of paraspinal tissue mass; or vertebral or other bony changes, were analysed.

Results

All 7 patients had lesions in the thoracolumbar region. Three patients had extradural lesions, 4 had intradural extramedullary lesions, and none had intramedullary lesions. Six lesions were well circumscribed. Only 1 patient had multifocal involvement. All lesions were of hypointense or isointense signal on T1-weighted imaging, whereas all but one were hyperintense on T2-weighted imaging. Lesions enhanced heterogeneously except 1 intradural extramedullary lesion, which enhanced homogeneously. A paraspinal mass was noticed in 2 patients. Vertebral collapse was present in 1 patients.

Conclusion

Intraspinal peripheral PNETs are rare spinal tumours. Although imaging characteristics are not specific, a focal circumscribed lesion in a young individual at the intramedullary, extramedullary intradural, or extradural spinal location that shows hypointense and hyperintense signal on T1- and T2-weighted images, respectively, requires PNET to be considered in the differentials.