眼眶淋巴瘤CT和MRI诊断分析

目的分析眼眶恶性淋巴瘤的CT和MBI表现特点,以提高对本病的诊断和鉴别诊断水平。资料与方法回顾性分析70例病理证实的眼眶恶性淋巴瘤的临床和影像资料,70例均做CT检查,9例加做MBI检查,分析肿瘤部位、密度、信号、形态和骨质等表现。结果男女之比4：1,中位年龄57岁,68例（97％）为B细胞型淋巴瘤,5例（7％）伴有身体其他部位淋巴瘤。双侧眼眶发病19例（27％）,共计70例／89眶。影像学表现：（1）侵犯部位：肿瘤弥漫侵犯眼球前后和肌锥内外间隙18例／24眶,球后20例／24眶（肌锥内间隙为主14例／16眶,肌锥外间隙为主6例／8眶）;局限于眼睑7例／9眶,结膜4例／5眶,泪腺区11例／14眶,泪囊区5例／5眶,眼外肌3例／6眶,眼眶鼻侧和筛窦2例／2眶。（2）密度和信号：多数肿瘤CT平扫和增强扫描密度均匀（分别为87％和81％）,48例（90％）呈中度或明显强化。多数肿瘤（8／9）在T1WI和T2阳上呈中等、均匀信号,与脑灰质相仿,T2信号略高于T1,强化均匀。（3）形态边缘：肿瘤形态多不规则,边缘呈浸润状,沿眼球壁、泪腺、视神经、眼外肌、眶隔或眶壁蔓延生长。（4）眶骨：66例（94％）无骨质改变。结论眼眶恶性淋巴瘤的CT和MRI表现具有一些特征,影像学检查对本病的诊断具有重要价值,但部分病例与炎性假瘤和良性淋巴组织增生性病变鉴别较困难。     

Orbital Lymphoproliferative Disorders (OLPDs): Value of MR Imaging for Differentiating Orbital Lymphoma from Benign OPLDs

BACKGROUND AND PURPOSE:Accurate discrimination of orbital lymphoma from benign orbital lymphoproliferative disorders is crucial for treatment planning. We evaluated MR imaging including DWI and contrast-enhanced MR imaging for differentiating orbital lymphoma from benign orbital lymphoproliferative disorders.MATERIALS AND METHODS:Forty-seven histopathologically proved orbital lymphoproliferative disorders (29 orbital lymphomas and 18 benign orbital lymphoproliferative disorders) were evaluated. Two board-certified radiologists reviewed visual features on T1-weighted, fat-suppressed T2-weighted, diffusion-weighted, and contrast-enhanced MR images. For quantitative evaluation, ADC and contrast-enhancement ratio of all lesions were measured and optimal cutoff thresholds and areas under curves for differentiating orbital lymphoma from benign orbital lymphoproliferative disorders were determined using receiver operative characteristic analysis; corresponding sensitivities and specificities were calculated.RESULTS:Multivariate logistic regression analysis showed that ill-defined tumor margin (P = .003) had a significant association with orbital lymphoma whereas the “flow void sign” (P = .005) and radiologic evidence of sinusitis (P = .0002) were associated with benign orbital lymphoproliferative disorders. The mean ADC and contrast-enhancement ratio of orbital lymphomas were significantly lower than those of benign orbital lymphoproliferative disorders (P < .01). An ADC of less than 0.612 × 10⁻³ mm²/s and a contrast-enhancement ratio of less than 1.88 yielded areas under curves of 0.980 and 0.770, sensitivity of 94.1% and 95.5%, and specificities of 93.3% and 80.0% for predicting orbital lymphoma, respectively.CONCLUSIONS:Some characteristic MR imaging features and quantitative DWI and contrast-enhanced MR imaging are useful in further improving the accuracy of MR imaging for differentiation of orbital lymphoma from benign orbital lymphoproliferative disorders.

Orbital lymphoproliferative disorders (OLPDs) frequently present as an orbital mass lesion (24%–49%) in the adult and comprise a wide spectrum of diseases ranging from benign to malignant lesions.¹ Orbital lymphoma is the most common orbital neoplasm representing 55% of cases in adults.² Most orbital lymphomas are primary, low-grade, B-cell, non-Hodgkin lymphomas, and the most common subtype is extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT).³ Other OLPDs comprise several benign, noninfectious, chronic inflammatory diseases, including IgG4-related ophthalmic disease, reactive lymphoid hyperplasia, and idiopathic orbital inflammation.⁴ Among them, IgG4-related ophthalmic disease is becoming increasingly recognized and accounts for approximately half of benign OPLDs on the basis of recent surveillance.⁵ The discrimination of orbital lymphoma from benign OLPDs is crucial because of the different therapeutic implications: the former is amenable to low-dose radiation therapy, whereas the latter are expected to show a good response to corticosteroid therapy.⁶ The utility of conventional anatomic MR imaging for this purpose is limited, however, because orbital lymphoma and benign OLPDs frequently share similar imaging features.^7,8 Recently, some researchers have reported quantitative DWI with ADC measurements to be potentially useful for discriminating orbital lymphoma from other orbital tumors.^9–15 However, these studies included other neoplastic and nonneoplastic lesions such as cavernous hemangiomas, neurogenic tumors, and metastases, and the value of DWI for discrimination of lymphoma and OLPDs remains unclear. The purpose of this study was to assess the value of MR imaging including DWI and contrast-enhanced MR imaging for the discrimination of primary orbital lymphoma from benign OLPDs.     

眼眶原发性淋巴瘤的MRI表现

目的：探讨眼眶原发性淋巴瘤的磁共振影像学表现,以提高其诊断的准确率。方法对11例经手术病理证实的原发性淋巴瘤的临床和影像学资料进行回顾性分析。结果眼眶原发性淋巴瘤的MRI特征如下：①好发于隔前眶周,以眼眶外上象限为主,包括眼睑、泪腺、结膜等;②无包膜,沿眼眶间隙蔓延塑形生长;③平扫T1WI呈等信号,T2WI呈稍高信号,增强呈中-重度强化;④DWI上表现为高信号;⑤边界较清晰,对周围组织结构侵犯、破坏少见;⑥囊变少见,出血、钙化罕见。结论眼眶原发性淋巴瘤MRI表现具有一定的特征性,MRI多方位成像可对肿瘤明确定位,并有助于定性诊断。     

MRI patterns in orbital malignant lymphoma and atypical lymphocytic infiltrates

OBJECTIVE: To evaluate the potential of MRI in differentiating between malignant lymphomas and atypical lymphocytic infiltrates in the orbit. MATERIALS AND METHODS: MRI, clinical and histopathological findings in 30 patients presenting with orbital lymphoproliferative diseases (malignant lymphoma and atypical lymphocytic infiltrates) were evaluated. RESULTS: MRI detected 28 out of 30 (93%) orbital lymphoid tumors. Seven out of eight (87.5%) atypical lymphocytic infiltrates and 21/22 (95.4%) of malignant lymphomas were detected. One conjunctival malignant lymphoma and one conjunctival atypical lymphocytic infiltrate were missed. Only malignant lymphoma lesions were hyperintense compared to the extraocular muscles on precontrast and postcontrast T1-weighted images. The lacrimal duct was involved only with malignant lymphoma. Bilateral disease was more likely to be malignant lymphoma. Intraconal lesions were more likely to be associated with lesions elsewhere. No malignant lymphoma involved the extraconal fat. Only intraconal atypical lymphocytic infiltrates had indistinct margins. CONCLUSION: In the orbit, MRI features alone may not allow clear-cut differentiation of malignant lymphomas from atypical lymphocytic infiltrates. However, certain imaging features increase the likelihood of distinguishing them. MRI may miss conjunctival disease. Both orbits should be imaged when orbital lymphoid disease is a probability. The presence of intraconal disease should prompt a search for lesions elsewhere. The use of a head coil instead of a superficial coil may be advantageous by eliminating coil shine effect and allowing evaluation of both orbits. Comparison of lesion signal to extraocular muscle signal appears to be a better alternative than cerebral gray matter or periorbital fat in differentiating malignant lymphoma from atypical lymphocytic infiltrates. Since imaging findings overlap, histopathological diagnosis is necessary in all cases.     

Diagnose und Differenzialdiagnose der endokrinen Orbitopathie in der MRT

Imaging of Graves' orbitopathy (GO) includes radiological and nuclear medicine procedures. Depending on the method used they provide information about the distribution and activity of the disease. Magnetic resonance imaging (MRI) is not only a helpful tool for making the diagnosis it also enables differentiation of the active and inactive forms of GO due to intramuscular edema. The modality is therefore appropriate to evaluate the disease activity and the course of therapy. The disease leads to the typical enlargement of the muscle bodies of the extraocular muscles. The inferior rectus, medial rectus and levator palpebrae muscles are mostly involved. Signal changes of the intraconal and extraconal fat tissue are possible and a bilateral manifestation is common. The differential diagnosis includes inflammatory diseases and tumors, of which orbital pseudotumor (idiopathic, unspecific orbital inflammation), ocular myositis and orbital lymphoma are the most important. The specific patterns (localization, involvement of orbital structures and signal changes) can be differentiated by MRI.     

Experience of two orbital MALT lymphomas treated with radiotherapy, and review of the literature

Orbital MALT lymphoma is a relatively rare malignant disease, for which radiation therapy is effective. However, the optimal dose has not been determined. We experienced two cases of orbital MALT lymphoma. One patient was successfully treated, but the other developed a severe complication. We conclude that for safe treatment of orbital MALT lymphoma, a dose in excess of 40 Gy must not be delivered.     

Stereotactic Radiotherapy for Unilateral Orbital Lymphoma and Orbital Pseudo-Tumors: A Planning Study

Orbital lymphoma and Grave's ophthalmopathy (GO) are successfully treated with radiation therapy. The lenses are blocked to prevent cataract formation. However, blocking of the lens by traditional methods can be difficult for tumors located anteriorly and extending into the retrobulbar space. We present a series of 3 patients with orbital lymphoma and 1 with GO treated with stereotactic intensity modulated radiation therapy (IMRT) to spare normal structures, including the lens. Three patients with orbital lymphomas and 1 with unilateral GO were treated with IMRT using a linac with stereotactic capabilities. Avoidance structures included the ipsilateral lens and globe, the contralateral lens and globe, the chiasm, and the brainstem. Two patients with orbital lymphoma were treated with 24 Gy in 12 fractions, and 1 patient was treated with 30.6 Gy in 17 fractions. The patient with GO was treated with 20 Gy in 10 fractions. The dosimetry was analyzed to determine the dose to normal tissues. Patient follow-up varies between 8 and 24 months. The mean minimal dose to the ipsilateral lens was 13.6% of the total dose, the mean maximal dose was 33.5%, and the mean median dose was 19.3%. The mean median dose to the contralateral eye was 1.1% of the total dose. The mean median dose to the chiasm was 14.9% of the total dose. The mean median dose to the brainstem was 1.9% of the total dose. No cataracts or other complications were noted in the 4 patients treated with this technique so far. IMRT gives a more conformal treatment to the orbital contents while sparing normal tissues such as the ipsilateral lens and adjacent critical structures. This should result in fewer complications such as cataracts.     

Radiotherapy for Orbital Lymphoma

PURPOSE: To analyze the effectiveness of radiotherapy in the management of orbital non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: 42 patients (median age 64.5 years) were reviewed retrospectively. The median follow-up period was 58 months. 26 patients had stage IE orbital lymphoma (22 indolent, four aggressive NHLs). 16 patients had advanced NHLs in stages II-IV with orbital involvement (eleven indolent, five aggressive NHLs). The median radiation dose was 40 Gy (20-46 Gy) for indolent lymphoma and 44 Gy (20-48 Gy) for aggressive lymphoma. Patients with stage IE were treated with at least 30 Gy. RESULTS: The 5-year local control rate for patients with stage I was 100%, the 5-year overall survival 91%. Two distant relapses were found, but no lymphoma-related death was detected. The 5-year local control rate for patients in stages II, III, and IV was 80%. Two local failures were detected. The 5-year overall survival for the advanced stages was 47%, nine patients with stages III and IV died due to systemic progression of lymphoma. Acute, radiotherapy-related complications grade 3/4 were not observed. Late effects grade 1/2 were documented in 45%. Six patients, treated with doses of > 36 Gy, developed grade 3 complications (four cataract, two dryness). CONCLUSION: Radiotherapy alone yields excellent local control and overall survival rates in orbital lymphoma stage IE. Local irradiation is also well tolerated and effective in advanced NHL stages with orbital infiltration. Doses of > 36 Gy resulted in an increase of late complications.     

Foraminal expansion by malignant retroorbital lymphoma: CT findings

A 43-year-old man presented with an orbital mass and cranial nerve dysfunction resulting from malignant lymphoma. Computed tomography showed prominent widening of bony foramina by the orbital and middle fossa tumor and an up to now unreported presentation of this lesion. Bony erosion, a distinctly atypical, although reported, feature of lymphoma suggesting malignancy, was also present. Implications for radiologic diagnosis are discussed.     

Arterial spin labeling and diffusion-weighted MR imaging: Utility in differentiating idiopathic orbital inflammatory pseudotumor from orbital lymphoma

PurposeTo assess arterial spin-labeling (ASL) and diffusion-weighted imaging (DWI) and in combination for differentiating between idiopathic orbital inflammatory pseudotumor (IOIP) and orbital lymphoma.Material and methodsA retrospective study was done on 37 untreated patients with orbital masses, suspected to be IOIP or orbital lymphoma that underwent ASL and DWI of the orbit. Quantitative measurement of tumor blood flow (TBF) and apparent diffusion coefficient (ADC) of the orbital lesion was done.ResultsThere was a significant difference (P = 0.001) in TBF between patients with IOIP (n = 21) (38.1 ± 6.2, 40.3 ± 7.1 ml/100 g/min) and orbital lymphoma (n = 16) (55.5 ± 7.1, 56.8 ± 7.9 ml/100 g/min) for both observers respectively. Thresholds of TBF used for differentiating IOIP from orbital lymphoma were 48, 46 ml/100 g/min revealed area under the curve (AUC) of (0.958 and 0.921), and accuracy of (86% and 83%) for both observers respectively. There was a significant difference (P = 0.001) in ADC between patients with IOIP (1.04 ± 0.19, 1.12 ± 0.23 × 10⁻³ mm²/s) and orbital lymphoma (0.69 ± 0.10, 0.72 ± 0.11 × 10⁻³ mm²/s) for both observers respectively. Thresholds of ADC used for differentiating IOIP from orbital lymphoma were 0.84 and 0.86 × 10⁻³ mm²/s with AUC of (0.933 and 0.920), and accuracy of 89% and 90% for both observers respectively. The combined TBF and ADC used for differentiating IOIP from orbital lymphoma had AUC of (0.973 and 0.970) and accuracy of (91% and 89%) for both observers respectively.ConclusionTBF and ADC alone and in combination are useful for differentiating IOIP from orbital lymphoma.     

Orbital lymphoma and subacute or chronic inflammatory pseudotumor: differentiation with two-phase helical computed tomography

OBJECTIVE: The differentiation between orbital lymphoma and subacute or chronic inflammatory pseudotumor (SCIPT) may be difficult clinically and radiologically. The aim of this study was to evaluate the enhancement characteristics of orbital lymphoma and SCIPT with two-phase helical computed tomography (CT) and delayed coronal CT and to determine whether attenuation measurements on CT can be used to differentiate between the 2 diseases. METHODS: Nineteen histopathologically proven orbital lymphomas and 9 SCIPTs were examined with two-phase helical CT. After injecting 90 mL contrast material at a rate of 3 mL/s, early- and late-phase axial CT scans were obtained with scanning delays of 30 and 90 seconds, respectively. Delayed coronal scans were obtained with delays of 4-9 minutes. Attenuation of the lesions at each phase was measured quantitatively. Relative percentages of contrast enhancement (CE) were calculated to determine the cutoff value for differentiating SCIPT from lymphoma. RESULTS: The CT attenuation change over time was significantly different between orbital lymphoma and SCIPT (P < 0.05). Increased CT attenuation between early- and late-phase axial scans was seen in 42% (n = 8) of lymphoma cases, and decreased CT attenuation was seen in 58% (n = 11). In 17 lymphomas (90%), the CT attenuation decreased between late-phase axial and delayed coronal scans. Conversely, in 7 SCIPTs (78%), the CT attenuation increased gradually over time from early-phase axial to delayed coronal scans. The relative percentage of CE at the delayed coronal scan had a cutoff value of -6.97%, a sensitivity of 84%, and a specificity of 100%. CONCLUSION: Different characteristics of attenuation change on two-phase helical CT and delayed coronal CT can be helpful in differentiating between orbital lymphoma and SCIPT.     

Imaging characteristics of diffuse primary cutaneous B-cell lymphoma of the cranial vault with orbital and brain invasion

We herein present the imaging findings in a case of diffuse primary cutaneous B-cell lymphoma of the cranial vault with orbital and brain invasion. MR imaging revealed first concomitant orbital and parenchymal invasion in a case of primary diffuse non-Hodgkin lymphoma of the cranial vault. Contrast-enhanced MR imaging revealed a diffuse mass in the scalp of the frontoparietal region bilaterally and invasion of the right orbit and left frontoparietal lobe. Histologic and immunopathologic examinations revealed diffuse primary cutaneous B-cell lymphoma.     

Fibrous histiocytoma and fibrous tissue tumors of the orbit

Fibrous orbital tumors present clinically and radiographically in a broad spectrum ranging from a benign mass, to locally aggressive tumor, to invasive malignancy. Pathologic analysis and diagnosis are often challenging, usually based on a combination of light microscopy, immunohistochemistry, and electron microscopic findings. Some light microscopic and immunohistochemical findings, however, are relatively characteristic. A storiform or cartwheel pattern and vimentin staining are characteristic of fibrous histiocytoma. A herringbone pattern is usually found in fibrosarcoma. A "patternless pattern" and CD34 staining is found most commonly in solitary fibrous tumor. CT and MR imaging findings, as well as clinical presentation, in fibrous orbital lesions are often difficult to distinguish from those of other orbital masses, although there may be useful clues. Benign fibrous lesions are usually well-circumscribed and may chronically remodel bone, whereas more aggressive malignant fibrous tumors tend to have infiltrating margins and may destroy bone on CT or MR imaging. With malignant fibrous masses, enhancement patterns on CT or MR imaging may be more inhomogeneous, with avascular or necrotic nonenhancing regions. At MR imaging, benign lesions tend to be homogeneous on T1, T2, and postgadolinium T1-weighted images, whereas malignant soft tissue lesions may change their pattern from homogeneous on T1-weighted images to heterogeneous with low signal septations on T2-weighted images. Low T2 signal comprising part or all of a fibrous lesion correlates with dense collagen fibers, with a less cellular matrix. Areas of hyperintensity on T2-weighted images correspond with a more cellular matrix of fibroblasts and other cells. Calcification within a tumor, however, may give a similar appearance. Thus, if a lesion has predominantly low signal on T2-weighted images, or less specifically has low signal septations, then a fibrous orbital lesion with high collagen content may be ranked higher in the differential diagnosis (see Figs. 2E and 3B). When T2 signal is intermediate-to-high, then one has a difficult time narrowing the differential diagnosis. Radiographically, distinguishing these lesions from other fibrous orbital lesions, as well as from other varieties of orbital masses, is difficult. Differential diagnosis of fibrous orbital masses includes all the fibrous lesions described in this article, in addition to schwannoma (Fig. 7), neurofibroma (Figs. 4 and 8), hemangiopericytoma (Figs. 9 and 10), rhabdomyosarcoma, meningioma, lymphoma, and metastasis (Figs. 11 and 12). A history of prior orbital irradiation for retinoblastoma or other tumors may raise the possibility of radiation-induced secondary tumors, such as MFH, fibrosarcoma, and osteosarcoma. Determining the extent of orbital involvement remains the primary goal of the radiologist. The final diagnosis still rests with the pathologist.     

Intensity-modulated radiation therapy for orbital lymphoma

Purpose  Orbital manifestations of non-Hodgkin’s lymphoma (NHL) are rare and accounts for only 1% of all cases of NHL. There have been no reports of treating orbital lymphoma using intensity-modulated radiotherapy (IMRT). Materials and methods  Four patients were treated at our institution for orbital lymphoma using IMRT. Radiotherapy (RT) plans using wedged pair fields were developed for comparison. Clinical results using IMRT are presented and a dosimetric analysis between IMRT and RT was performed. Results  All patients had a complete response based on their physical examinations and post-IMRT imaging. Symptoms that had been present at initial presentation resolved in all patients during the course of the treatment. All four patients experienced only grade 1 dry eye syndrome and keratitis. The average dose to the contralateral orbit, lacrimal gland, and lens were all significantly reduced (P < 0.01) in IMRT patients as compared to the RT patients. IMRT reduced the V5 and V10 for the contralateral lens, orbit, and lacrimal gland and the optic chiasm (P < 0.05). Conclusion  IMRT is feasible when treating orbital lymphoma and reduces dose to critical structures while providing excellent dose coverage of target volumes. IMRT offers patients with orbital lymphoma excellent clinical outcomes, similar to conventional RT, with no increased toxicity.     

Orbital lymphoma: a simple treatment using electrons.

Previous papers have discussed the successful treatment of orbital lymphoid tumors using a low-vacuum contact lens placed directly on the eye and the use of a lead bar suspended over the eye with a retort stand. In this paper, a novel approach using a cerrobend bar attached to an electron shield for the treatment of a conjunctival lymphoma is presented. With this approach, the entire eye, excluding the lens, may be treated with a single field. Isodose distributions measured in a water phantom are compared with those planned on a 3D radiotherapy treatment planning system, where the effects of an external eye bar can be shown. The clinical outcome of the treatment is also shown.     

Characterization of orbital lesions by surface coil MR imaging

Surface coil MR imaging is an effective technique for evaluating orbital pathology. T1 and T2 weighting provides information not obtainable by CT and results in better characterization of some lesions. MR appears to be most useful for characterizing ocular pathology, specifically for differentiating retinoblastoma from benign diseases (Coat's disease and PHPV). MR can also be used to separate ocular tumors from associated subretinal fluid. With MR imaging, the signal intensities of lymphoma differ from those of benign inflammatory or infiltrative conditions such as pseudotumor or thyroid ophthalmopathy. Mucoceles, too, have a specific signal intensity pattern with T1 and T2 weighting. CT appears to be superior to MR for demonstrating densely calcified lesions or lesions of bone.     

Can DWI & ADC differentiate orbital lymphoma,non-specific orbital inflammation and orbital cellulitis?

The aim of this work

To differentiate orbital lymphoma, non-specific orbital inflammation (NSOI) and orbital cellulitis using DWI & ADC, as there is marked clinical overlap in the diagnosis of these three orbital conditions.

Material and methods

Twenty-five cases chosen from attendants of the outpatient clinic of the Ophthalmology Department of Zagazig University Hospitals with different orbital pathologies presenting with orbital inflammatory signs and/or proptosis were all examined with conventional MRI sequences then functional DWI and ADC map and values were performed.

Results

Six cases (6/25) were diagnosed as orbital lymphomas (24%), 14 cases (14/25) NSOI (formerly known as orbital inflammatory syndrome) (56%) and 5 cases (5/25) as orbital cellulitis (20%), in DWI the greater the restriction was detected in lymphomas, followed by NSOI and lastly with orbital cellulitis and ADC values ranging from 0.6 to 0.9 × 10⁻³ mm²/s for lymphoma, 1.1 to 1.3 × 10⁻³ mm²/s in NSOI and 1.5 to 1.7 × 10⁻³ mm²/s in orbital cellulitis.

Conclusion

DWI & ADC can differentiate orbital lymphoma from NSOI and orbital cellulitis and help rapid management.     

Periocular lymphoproliferative diseases: natural history, prognostic factors, and treatment.

A study was undertaken to assess the natural history of periocular lymphoproliferative diseases, identify key prognostic factors, and clarify the role of orbital irradiation. Thirty-four patients with periocular lymphoproliferative disease were treated with orbital irradiation between 1975 and 1990. Eight patients had atypical lymphoid infiltrate, and 26 had malignant lymphoma. Forty-three eyes were irradiated with en-face electrons or 6-MV photons. Five-year disease-free survival for all stages was 65%; it was not significantly affected by bilaterality or site. Stage, distinction between atypical lymphoid infiltrate and malignant lymphoma, and working formulation grade were important prognostic indicators. A complete response during irradiation was achieved in 24 of 43 (56%) eyes at a median dose of 2,400 cGy, and a partial response was achieved in 19 (44%), with resolution at a median of 2.8 months. Patients with periocular reactive lymphoid hyperplasia or atypical lymphoid infiltrate may have or are at significant risk of developing lymphoma and dissemination. Local treatment remains important; orbital irradiation achieves prompt local control with acceptable morbidity.     

Orbital syndromes--CT analysis of 100 cases

100 cases of orbital syndromes, primary or secondary, are reviewed after CT analysis and compared with the results of plain and angiographic conventional examinations. First, the technique and normal results are described. Primary orbital syndromes (45 cases) originating in the orbit form three subgroups--tumors of the eyeball, tumors limited to the orbit and tumors of the orbit with bone lesions, with or without extra-orbital extension. Secondary orbital syndromes (55 cases) spreading to the orbit contain malignant tumors (36 cases) of which 25 are epitheliomas and benign tumors, the most frequent being meningiomas. For ocular and orbital tumors, CT allows the diagnosis of a mass and sometimes the pathological diagnosis (endocrine exophtalmos, inflammatory pseudotumors, varicose ophthalmic veins). For all other orbital tumors CT is important in determining the volume, relationships and extension, and does so better than carotid angiography or orbital phlebography. In secondary orbital syndromes, and particularly in facial malignant tumors and in meningiomas, CT is of great interest in the pretherapeutic evaluation of a tumor. It shows its volume and extension toward the face and orbital cavities, the pterygo-maxillary fossa (so important in determining the operability), the infra-temporal fossa and the endocranium, often without resorting to complementary investigational procedures which are much more aggressive. After histological diagnosis, CT allows the establishment of a therapeutic program.     

眼眶淋巴瘤的MR影像特点

目的探讨眼眶淋巴瘤的MR影像特点,以提高其术前诊断准确率。方法回顾性分析8例经手术病理证实的眼眶淋巴瘤的MR影像学表现。结果7例为单侧,1例为双侧;4例位于肌锥外呈铸型;4例累及肌锥内外呈弥漫生长,其中3例累及视神经;8例均起源于泪腺和/或眼睑组织,并均有眼外肌受侵;1例有骨质破坏;平扫信号均匀,6例T1W I呈等信号,2例呈稍高信号,7例T2W I呈稍高信号,1例T2W I呈等信号;8例增强后均呈中等度均匀强化。结论眼眶淋巴瘤的MR影像学特征有助于提高其术前诊断准确率。