Severe spontaneous ovarian hyperstimulation syndrome with MR findings

We describe a case of severe spontaneous ovarian hyperstimulation syndrome (OHSS) with MR findings. MR scans showed bilateral symmetric enlargement of ovaries with multiple cystic changes, giving the classic "wheel-spoke" appearance. There was no definite abnormally thickened or enhanced wall, but there was internal hemorrhage in some chambers. To avoid unnecessary laparotomy, we emphasize the importance of careful diagnosis to differentiate spontaneous OHSS from ovarian cystic neoplasms.     

Magnetic resonance imaging of the cavernous sinus

The magnetic resonance (MR) appearance of the cavernous sinus was studied by correlating the MR images of normal volunteers and cryomicrotomic sections from six cadavers. In addition, MR images of patients with parasellar masses were compared with corresponding intravenously enhanced computed tomographic (CT) scans. The MR appearance of the cranial nerves in the cavernous sinuses is demonstrated, as well as MR signs of a parasellar mass, including obliteration of intracavernous venous spaces, displacement of the intracavernous internal carotid artery, and bulging of the lateral wall of the cavernous sinus. MR proved to be more effective than CT in delineating the parts of the cavernous sinus.     

MR imaging of septic sacroiliitis

Septic sacroiliitis is difficult to diagnose, causing delayed treatment and increased morbidity. The traditional imaging techniques for diagnosis have been CT and nuclear medicine. Our purpose was to determine the ability of MR imaging to detect septic sacroiliitis, to evaluate the features of septic sacroiliitis with MR, and to compare the relative detection rate of MR, CT, and nuclear medicine. All patients with a discharge diagnosis of septic sacroiliitis who were evaluated by MR imaging of the pelvis were retrospectively evaluated. Five patients were collected with six septic sacroiliac joints, which were also evaluated with CT, 99mTc-methylene diphosphonate bone scans, and 67Ga-citrate scans. Abnormalities consistent with sacroiliitis were seen in all sacroiliac joints both prospectively (impression from the initial report) and retrospectively on MR. In addition to the nonspecific MR findings of inflammation and/or fluid in the sacroiliac joint space, bone marrow of the sacrum and/or ilium, and iliopsoas muscle, fluid/inflammation was uniquely identified tracking posterior to the iliopsoas muscle in each of these patients with septic sacroiliitis. Even in retrospect, a definite diagnosis of sacroiliitis could be made in only five of six joints by 67Ga-citrate scans, three of six joints by CT scans, and one of six joints by 99mTc-methylene diphosphonate bone scans. These results suggest MR imaging may be a sensitive modality in the early diagnosis of septic sacroiliitis.     

Carotid body tumor: flow sensitive pulse sequences and MR angiography

The magnetic resonance (MR) appearance of carotid body tumors has been previously described. Classically, these lesions are well circumscribed and highly vascular and cause a characteristic separation of the external and internal carotid arteries. Hypointense foci within these tumors are seen on T1-weighted images. The T2-weighted images snow a "salt and pepper" pattern. We report a carotid bifurcation glomus tumor that exhibited the above features on conventional MR. Multiplanar gadolinium enhanced MR as well as flow-sensitive MR techniques including small flip angle gradient refocused images and MR angiography were performed. Magnetic resonance angiography demonstrated the abnormal morphology of the carotid bifurcation. Axial gradient refocused images revealed evidence of flow within the lesion. The findings were then correlated with postcontrast CT, arterial digital subtraction angiography, and histopathology.     

Delayed enhancement of peripheral zone of neurofibromas at magnetic resonance imaging

It is well known that bizonal histologic appearance characteristic of neurofibromas are reflected on magnetic resonance (MR) images. We report a case in which a delayed enhanced MR image showed that the entire mass enhanced homogeneously resulting in loss of zonal distinction on early enhanced MR image     

Imaging features of aggressive angiomyxoma

AIM: To describe the imaging features of aggressive angiomyxoma in a rare benign mesenchymal tumour most frequently arising from the perineum in young female patients. MATERIALS AND METHODS: We reviewed the computed tomography (CT) and magnetic resonance (MR) imaging features of patients with aggressive angiomyxoma who were referred to our hospital. The imaging features were correlated with clinical information and pathology in all patients. RESULTS: Four CT and five MR studies were available for five patients (all women, mean age 39, range 24-55). Three patients had recurrent tumour at follow-up. CT and MR imaging demonstrated a well-defined mass-displacing adjacent structures. The tumour was of low attenuation relative to muscle on CT. On MR, the tumour was isointense relative to muscle on T1-weighted image, hyperintense on T2-weighted image and enhanced avidly after gadolinium contrast with a characteristic "swirled" internal pattern. MR imaging demonstrates the extent of the tumour and its relation to the pelvic floor. Recurrent tumour has a similar appearance to the primary lesion. CONCLUSION: The MR appearances of aggressive angiomyxomas are characteristic, and the diagnosis should be considered in any young woman presenting with a well-defined mass arising from the perineum.     

Tributary venosinus occlusion and septic cavernous sinus thrombosis: CT and MR findings.

PURPOSEIn autopsy reports of patients who died of septic cavernous sinus thrombosis, tributary venosinus occlusion has been a common finding related to intracranial inflammatory complications. The purpose of this article is to illustrate the MR and CT appearance of septic cavernous sinus thrombosis and tributary venous occlusion.METHODSOver a period of 7 years, eight patients with septic cavernous sinus thrombosis were examined by contrast-enhanced thin-section CT. The CT scans of these eight patients and those of 30 healthy control subjects were assessed independently and subjectively by two blinded readers to ascertain the presence, size, and density of areas of nonopacification within the cavernous sinus and the presence of filling defects and dilation of tributary veins and venous sinuses. In six subjects, MR images supplemented by a contrast-enhanced spoiled gradient-recalled acquisition in the steady state (SPGR) sequence were assessed with respect to the presence of filling defects, expansion, and signal abnormalities within the cavernous sinus and tributary veins and sinuses. The MR and CT findings were compared.RESULTSThe CT studies of the eight patients were consistently differentiated from those of the control subjects by the two readers. Contrast-enhanced CT findings in patients included areas of nonopacification that were present within the cavernous sinus bilaterally in six cases and unilaterally in two. The size of the filling defects exceeded 7 mm in 76% of thrombosed cavernous sinuses compared with 9% of control subjects. The mean density of filling defects in patients differed significantly from those in control subjects. Comparison of the MR and CT findings in six cases showed the contrast-enhanced SPGR sequence to be equivalent to CT with respect to delineation of filling defects.CONCLUSIONContrast-enhanced high-resolution CT findings indicate that venosinus thrombosis associated with septic cavernous sinus thrombosis is not restricted to the superior ophthalmic vein and is more common than previously assumed. A contrast-enhanced SPGR MR sequence may be used as a reliable alternative to establish the diagnosis of cavernous sinus and tributary venosinus thrombosis.     

Spontaneous prolapse of pedunculated uterine submucosal leiomyoma: usefulness of broccoli sign on CT and MR imaging

We report the case of a patient who presented with a bulky perineal mass expelled from the introitus. Computed tomography and magnetic resonance (MR) imaging revealed that it was prolapsed submucosal uterine leiomyoma. It is unusual that submucosal leiomyoma is expelled to the perineum, but the MR imaging findings were characteristic and had a "broccoli-like" appearance. Familiarity with this appearance may be helpful in diagnosing prolapsed leiomyoma which is uncommon but has characteristic imaging feature.     

Unusual manifestations of vertebral osteomyelitis: intraosseous lesions mimicking metastases

BACKGROUND AND PURPOSE: Vertebral osteomyelitis can have different imaging manifestations. The purpose of this study was to demonstrate the unusual MR imaging patterns of vertebral osteomyelitis with intraosseous lesions mimicking metastases.MATERIALS AND METHODS: From September 2000 to August 2007, 7 patients were selected from our data base of 214 patients with confirmed vertebral osteomyelitis and MR images. All of those having misinterpreted MR imaging reports and unusual imaging patterns were analyzed. The presence of a peripheral curvilinear area of low signal intensity in an osseous lesion (the rim sign) and a peripheral rim of high signal intensity on T2-weighted images around an osseous lesion (the halo sign) was evaluated. Follow-up MR imaging studies were performed in all patients.RESULTS: The patients were 5 men and 2 women, with an age range of 42–80 years. MR imaging findings of those with vertebral osteomyelitis showed a solitary lesion in 2 and multiple lesions in 5 patients. The intraosseous lesions revealed low signal intensity on T1-weighted images, mixed or high signal intensity on T2-weighted images, high signal intensity on short τ inversion recovery images, and global or marginal enhancement. The rim sign was found in 6 (86%) patients; halo sign, in 7 (100%); preserved intervertebral disks, in 7 (100%); and limited paraspinal or epidural inflammation, in 6 (86%). Images of all patients demonstrated healing or almost healed changes on the follow-up MR imaging studies.CONCLUSION: Vertebral osteomyelitis can have MR imaging patterns mimicking osseous metastases. Recognition of these unusual imaging manifestations, together with clinical and histopathologic analysis, may aid in reaching the correct diagnosis.

MR imaging has become the valuable technique of choice for early detection of osteomyelitis because of its excellent contrast resolution between the abnormal and normal bone marrow.^1–5 In pyogenic vertebral osteomyelitis and spondylodiskitis, several MR imaging characteristics have been described, including decreased signal intensity on T1-weighted images, increased signal intensity on T2-weighted images, and enhancement on contrast-enhanced MR images in the disk and adjacent vertebral bodies; erosion or destruction of at least 1 vertebral endplate; decreased disk height and an absent intranuclear cleft; and paraspinal and/or epidural inflammatory soft tissue, abscess formation, or both.^4–9 Relative preservation of the disk morphology and signal intensity has been reported in tuberculous and certain fungal infections.^10–12The route of hematogenous spread of microorganisms or septic emboli might involve osseous changes similar to those of hematogenous spread of other etiologies, such as malignant cells when the microorganisms are dislodged in the end arterioles. Thus, it is sometimes difficult to make the differential diagnosis of septic emboli versus osseous metastases. The unusual manifestations of vertebral osteomyelitis with MR imaging patterns of septic emboli mimicking osseous metastases, to our knowledge, have not been previously described in the literature. Therefore, the purpose of this study was to demonstrate and analyze the unusual MR imaging patterns of misdiagnosed vertebral osteomyelitis with intraosseous lesions, which may mimic osseous metastases.     

Gd-DTPA enhanced MRI of cervical anterior epidural venous plexus.

Seventy selected cases were reviewed retrospectively to assess the normal Gd-DTPA enhanced MR appearance of the cervical anterior epidural venous plexus. This structure can enhance quite markedly and has a somewhat variable appearance on MR imaging but we believe that it can be differentiated from pathological enhancement in the area if attention is paid to its normal anatomical characteristics.     

Primary bone tumors. MR morphologic appearance correlated with pathologic examinations.

Eighty-three MR studies for primary bone tumors, performed with both spin echo and short time inversion recovery (STIR) sequences, were reviewed. Twenty-six patients underwent surgery within 10 days after MR imaging. Specimens were cut and directly compared with MR images. In the remainder, pathologic slides were compared in order to obtain a better understanding of MR pattern. All MR images were examined with a traditional morphologic approach and, upon comparison with surgical macroslides and with pathology samples, some MR distinctive patterns were identified: the bulky appearance of osteosarcoma surrounded by muscle edema, the multilobular high signal intensity (SI) chondroid lesions, the subtle infiltration of Ewing's sarcoma, rarely accompanied by muscle edema and prone to MR underestimation, the well defined "multiple shells" pattern of giant cell tumor, and the ill defined "storiform" appearance of malignant fibrous histocytoma are all typical MR features strictly corresponding to pathologic findings. The chondroid origin tumors may be identified based on the lobular high SI pattern whereas a benign fibrous lesion was the only one in this series to be distinguished relying on the SI. Peritumoral soft tissue edema was found by the STIR sequence only in malignant tumors (69%) of this series, and particularly in osteosarcoma (96%), chondrosarcoma (83%), and giant cell tumor (100%): this associate finding may further contribute to the diagnosis.     

MR evaluation of PDMS injections in head and neck tissues: A pilot study

Objectives

To describe the magnetic resonance (MR) appearance of polydimethylsiloxane (PDMS) injections in the head and neck region.

Study design

Retrospective review of MR images from a case series.

Methods

MR images of 10 patients, who underwent PDMS injections at our department, were reviewed. Data from imaging were collected and analyzed.

Results

After injection, PDMS can be identified in MR images, particularly in T2-weighted images in the early stages. Its MR characteristics are similar to silicone in other regions, but with time, its appearance can change.

Conclusions

The integration of PDMS with tissues may also be reflected in changes in MR appearance, as a result of an increased amount of fibrous tissue in the region injected. Radiologists and ENT specialists may benefit from knowledge of the MR characteristics and variability in appearance of PDMS in human tissues for improving image interpretation.     

肝海绵状血管瘤MRI动态增强表现

目的研究肝脏海绵状血管瘤MRI动态增强表现。材料与方法107例患者行MRI平扫及FL2D或SE序列动态增强扫描,分析其中的119个血管瘤的动态增强表现。结果41个血管瘤在增强早期(团注造影剂后1min内)表现为均一高信号增强,78个血管瘤表现为边缘结节状增强并逐渐向中间充填增强。SE序列扫描1.2％(1/84)的病灶延迟期呈等信号充填增强,FL2D扫描11.5％(4/35)的病灶延迟期呈等信号充填增强,余病灶均表现为高信号充填增强。结论肝血管瘤可归纳为两种增强类型快速充填型和边缘结节增强充填型。少部分血管瘤FL2D序列扫描时病灶可呈等信号充填增强。     

Correlation of non-mass-like abnormal MR signal intensity with pathological findings surrounding pediatric osteosarcoma and Ewing’s sarcoma

Objective

The aim of this work was to determine the role of MRI in interpreting abnormal signals within bones and soft tissues adjacent to tumor bulk of osteosarcoma and Ewing’s sarcoma in a pediatric population by correlating MR findings with histopathology.

Materials and methods

Thirty patients met the inclusion criteria, which included (1) osteosarcoma or Ewing’s sarcoma, (2) MR studies no more than 2?months prior to surgery, (3) presence of abnormal MR signal surrounding the tumor bulk, (4) pathological material from resected tumor. The patients received standard neoadjuvant chemotherapy. Using grid maps on gross pathology specimens, the abnormal MR areas around the tumor were matched with the corresponding grid sections. Histopathology slides of these sections were then analyzed to determine the nature of the regions of interest. The MR/pathological correlation was evaluated using Mann–Whitney U test and Fisher’s exact test.

Results

Twenty-seven patients had osteosarcoma and three patients had Ewing’s sarcoma. Of the studied areas, 17.4% were positive for tumor (viable or necrotic). There was no statistically significant correlation between areas positive for tumor and age, gender, signal extent and intensity on MRI, or tissue type. There was, however, a statistically significant correlation between presence of tumor and the appearance of abnormal soft tissue signals. A feathery appearance correlated with tumor-negative areas whereas a bulky appearance correlated with tumor-positive regions.

Conclusions

MR imaging is helpful in identifying the nature of abnormal signal areas surrounding bone sarcomas that are more likely to be tumor-free, particularly when the signal in the soft tissues surrounding the tumor is feathery and edema-like in appearance.     

脑发育性静脉异常的MR诊断

目的:评价MRI对脑发育性静脉异常(DVA)的诊断价值。方法:收集MR诊断为DVA的患者51例,均行MR平扫及增强检查,其中11例行磁敏感加权成像(SWI),回顾性分析其MR表现。结果:51例DVA中发生于额叶白质27例,顶叶白质9例,颞叶4例,基底节区2例,小脑半球9例;合并出血2例,均位于幕下;并发海绵状血管瘤2例。MR平扫显示病灶14例,其中表现为条状流空信号者10例,表现为T2WI放射状高信号者4例;MR增强检查显示所有病灶,表现为"海蛇头"样强化特征。11例行SWI者均能清晰显示病灶,表现为"海蛇头"样低信号影。结论:DVA多发生于幕上额顶叶白质及小脑半球,合并出血少见,可并发海绵状血管瘤。MR平扫难以显示细小病灶,MR增强检查是显示DVA的有效方法,SWI对小静脉病变较敏感,能取代MR增强检查用于发育性静脉异常的诊断和随访。     

MR imaging of paragangliomas

MR imaging of 15 paragangliomas in 10 patients was compared with CT of 13 of the lesions in eight patients. All lesions were confirmed with angiography. All lesions were detected by MR and CT with the exception of one small glomus tympanicum tumor that was seen only in retrospect with MR. CT better demonstrated subtle osseous changes of the skull base and the relation of the tumor to the middle ear structures. MR better demonstrated the relation of the tumor to the adjacent internal jugular vein and carotid artery. The paragangliomas had a characteristic MR appearance based on their vascularity. Serpiginous areas of signal void representing high vascular flow were interspersed among areas of high signal intensity caused by slowly flowing blood and tumor cells. This "salt-and-pepper" pattern was seen in all lesions greater than 2 cm in maximal dimension. MR was therefore able to accurately characterize the tumors as highly vascular. Multiplanar imaging and good tissue contrast and anatomic detail permitted display of the relations of these neoplasms to surrounding carotid sheath vessels and to intracranial structures better than did CT. In this experience, the MR appearance of paragangliomas was quite characteristic and differed markedly from meningiomas, neuromas, and metastatic disease of the skull base.     

Magnetic resonance imaging of extraabdominal desmoid tumors.

The authors describe the MR appearance of extra-abdominal desmoid in three patients, with longitudinal follow-up during a period of up to 29 months in two of them. For the MR examinations various pulse sequences, including spin-echo and gradient-echo sequences, were used. Both non-enhanced and Gd-DTPA contrast enhanced studies were made. We found gradient-echo T2*-weighted sequences best suited for the detection of extra-abdominal desmoids. Best correlation between MR features and histologic findings was obtained on spin-echo T2- and contrast enhanced T1-weighted studies. Although preliminary, our results suggest that MRI might predict evolution of extra-abdominal desmoids by providing data about cellularity and relative amount of mucoid matrix of the lesions.     

Giant cell tumor of the proximal tibia: MR and CT appearance

The magnetic resonance (MR) appearance of four cases of giant cell tumor (GCT) of the proximal tibia are described and the MR grading of these tumors is compared with CT and conventional radiography. Magnetic resonance showed the lesions to be well defined with respect to adjacent marrow and cortical bone. Homogeneous intermediate signal intensity or low signal within the tumors was seen on T1-weighted images. T2-weighted images showed mixed signal intensity with small "bright patches" of increased signal intensity in all four cases. No fluid levels were identified. Magnetic resonance was superior to CT and plain radiography in radiologic grading of the tumors. Computed tomography was superior in determining if cortical invasion was present. Intraarticular tumor extension was more accurately detected by MR and arthrotomography than CT. An MR manifestation of GCT of the proximal tibia is described which may be a common appearance of this tumor by this modality. Magnetic resonance is the procedure of choice in the radiologic grading of GCT.     

Value of MRI in the diagnosis of non-clival,non-sacral chordoma

OBJECTIVE: To determine the MR features of non-sacral, non-clival chordoma and to describe a MR prototype of the lesion. DESIGN AND PATIENTS: We reviewed the MR findings of 10 patients with a histologically proven chordoma (6 cervical spine, 1 thoracic spine, 3 lumbar spine). There were three female and seven male patients. Age ranged from 12 to 66 years with a mean age of 44.6 years. The MR images were reviewed for signal intensity (SI) and morphology. RESULTS: All lesions showed a soft tissue extension spanning several vertebral segments. Most of the lesions exhibited a so-called collar button appearance (sagittal images). Two cases of cervical chordoma displayed a "dumbbell morphology" (axial images) or "mushroom" appearance without bone involvement and with enlargement of the neuroforamen mimicking a neurogenic tumor. Although the region of the nucleus pulposus is the last part of the fetal notochord in the adult to involute, disks were surprisingly spared in all patients. Eight of 10 patients showed heterogeneous SI on all sequences. The overall SI of all lesions was isointense or slightly higher than that of muscle on T1-weighted images. All lesions exhibited high SI on T2-weighted images. After gadolinium contrast administration there was a moderate enhancement in most cases. CONCLUSIONS: Although the SI on MR imaging is not specific, chordoma should be considered when a destructive lesion of a vertebral body is associated with a soft tissue mass with a collar button or mushroom appearance and dumbbell morphology, spanning several vertebral segments and sparing the disk(s).     

MR imaging of septic sacroiliitis

Objective. To investigate the diagnostic value of magnetic resonance (MR) imaging in detecting septic sacroiliitis and to determine whether the MR characteristics allow this entity to be differentiated from sacroiliitis in spondylarthropathy (SpA). Patients and design. The imaging findings of 11 patients with septic sacroiliitis were retrospectively analyzed by two experienced radiologists. Radiographic surveys of the pelvis as well as computed tomography (CT) and MR images of the sacroiliac joints were available in all cases. Seven of the patients additionally underwent a follow-up MR examination. The MR imaging protocol comprised combinations of coronal and transverse T1-weighted spin-echo (SE) or fast SE sequences, T2-weighted gradient-echo (GE) sequences and short tau inversion recovery sequence (STIR) sequences as well as dynamic contrast- enhanced T1-weighted acquisitions. Results. Three patients with a short disease history showed anterior and/or posterior subperiosteal infiltrations (”lava cleft phenomenon”), transcapsular infiltrations of juxta-articular muscle layers, which obscured the fasciae, and periarticular bone marrow edema. The eight patients with more advanced stages of sacroiliitis additionally showed abscess formation, sequestration, and erosion. At follow-up MR examination (n=7) under systemic antibiotic treatment, the morphologic characteristics showed progression (n=1), regression (n=4), unchanged findings (n=1), or a mixed response (n=1). Clinical improvement precedes resolution of the MR findings. Conclusions. Anterior and/or posterior subperiosteal infiltrations and transcapsular infiltrations of juxta-articular muscle layers were depicted in all patients. These MR imaging findings are characteristic of septic sacroiliitis and may be used to differentiate this entity from sacroiliitis in SpA. Received: 1 November 1999 Revision requested: 4 January 2000 Revision received: 14 April 2000 Accepted: 16 May 2000