CT and MRI findings in cerebral hydatid disease

Cerebal hydatid cysts account for 2% of all intracranial masses. Preoperative diagnosis is important since cyst rupture and spillage may cause an anaphylactic reaction. CT is the primary modality for the diagnosis. Two forms of cerebral hydatid cysts have been reported on the basis of CT appearances: unilocular and multilocular. Demostration of the cyst wall is important for the diagnosis. MRI is superior to CT for demostrating the cyst capsule and perifocal oedema. We retrospectively reviewed the CT and MRI findings of 6 surgically proven cases of cerebal hydatid cyst and compared the two modalities on the basis of their demonstration of findings helpful in the diagnosis, such as the capsule and perifocal oedema. In 1 case CT showed the capsule. In 2 cases MRI showed a hypointense capsule around the cyst on T2-weighted images. While CT is the modality of choice, in clinical practice MRI is superior for demonstrating the cys capsule, which is a helpful findings in the diagnosis and can be used in inconculsive cases. Correspondence to: U. Topal     

MRI evaluation of soft tissue hydatid disease

Infestation in soft tissue by Echinococcus granulosus is not a common disease, and its diagnosis is based on clinical, laboratory data and radiological findings. The aim of our retrospective study is to give an overview of the different signs and patterns shown by MRI that can be useful in characterizing soft tissue hydatid disease. The MRI images obtained in seven patients with soft tissue and subcutaneous hydatidosis were reviewed. Typical signs of hydatidosis were multivesicular lesions with or without hypointense peripheral ring (“rim sign”). Related to the presence and absence, respectively, of viable scolices in the microscopic exam, daughter cysts were presented either as high signal intensity or low signal intensity on T2-weighted images. Low-intensity detached layers within the cyst and peripheral enhancement with gadolinium-DTPA were also presented. Atypical signs were presented in an infected muscular cyst, a subcutaneous unilocular cyst and several unilocular cysts. Knowledge of the different patterns in MRI of soft tissue hydatid disease can be useful in diagnosing this entity. We observed that the “rim sign” is not as common as in other locations, and in addition, MRI seems to be of assistance when evaluating the vitality of the cysts. Received: 27 July 1998; Revision received: 11 March 1999; Accepted: 23 April 1999     

颅内包虫病的CT诊断

目的探讨颅内包虫病的CT表现。方法分析经手术、病理证实的6例颅内包虫病的CT征象,其中单发脑内包虫囊肿3例,多发1例,硬膜外包虫囊肿1例,肝脑多发泡型棘球蚴病1例。结果颅内包虫病一般表现为典型囊肿性病变,轮廓清晰、锐利,CT值与脑脊液相似,囊内容物密度均一,囊壁无或轻度增强。脑泡型棘球蚴病无特异CT征象,有时表现酷似脑胶质瘤。结论CT是诊断颅内包虫病简捷、准确的影像学检查方法,密切结合临床资料正确诊断多无困难。     

Metastatic liver tumor from cystic ovarian carcinomas: CT and MRI appearance.

OBJECTIVE: The initial and follow-up CT and MRI images of ten patients with hepatic metastases from ovarian tumors were retrospectively analyzed to establish their features and sequential changes in appearance. MATERIALS AND METHODS: Ten patients with hepatic metastasis from ovarian tumors received initial and follow-up CT and MRI examinations. Six patients were followed up every two to three weeks before surgical tumor resection. Both CT and MR images were analyzed by two radiologists. RESULTS: A total of fourteen lesions were detected by CT and MRI in 10 patients. All 14 lesions were demonstrated as areas of marked hyperintensity on T2-weighted MRI. Eleven cyst-like tumors were demonstrated as round or oval low density lesions on CT and as areas of hypointensity on T1-weighted imaging. Three lesions were shown as solid masses with slightly low attenuation at the initial CT examination and slightly low or iso-intensity areas on T1-weighted imaging, and these lesions showed early peripheral globular enhancement and delayed enhancement on contrast-enhanced CT and MR imaging. Cystic formation was observed two to three weeks later after initial study in all the 3 solid lesions. Rapid subcapsular effusion, which showed obvious enhancement on delayed Gd-DTPA enhanced MR imaging, was observed in two patients. CONCLUSION: The hepatic metastatic tumor from cystic ovarian carcinoma may manifest as a well-defined cystic lesion or as a solid mass, and the solid mass shows delayed enhancement on contrast-enhanced CT and MR imaging. Furthermore, rapid cystic formation and rapid subcapsular extension is frequently seen.     

肌肉软组织包虫囊肿的CT诊断

目的 探讨原发性肌肉软组织包虫囊肿的CT表现.资料与方法 分析11例经手术病理证实的肌肉软组织包虫囊肿的CT表现.结果 11例中,发生在颈部3例,胸壁2例,腰大肌3例,背部1例,腹壁1例,臀部1例;其中单发6例,多发5例,共17枚病灶.CT平扫均表现为单囊型包虫囊肿,呈圆形或卵圆形囊性低密度肿物, 密度均匀,接近水的密度, 边缘光滑清楚,周围组织有受压、推移改变.增强扫描囊肿无强化.结论 CT可显示肌肉软组织包虫囊肿的部位、大小、形态和内部特征.     

脑包虫病的MRI表现及诊断

目的 分析脑包虫病的MRI特征性表现.方法 回顾性分析18例经手术病理证实脑包虫病患者的MRI表现,总结脑包虫病的MRI诊断与鉴别诊断要点.结果 18例脑包虫病患者中囊性包虫病和泡型包虫病各9例.囊性包虫病表现为脑内大小不等的圆形长T1、长T2信号病灶,内部信号均匀一致,液体衰减反转回复(FLAIR)序列扫描其内囊液信号可被抑制;DWI序列病灶为低信号;6例病灶周围无水肿带,3例破裂包虫囊肿病灶周围有水肿带;6例病灶见囊壁显示,3例病灶囊壁显示不明显;增强扫描3例破裂包虫囊肿有环形强化,6例病灶无强化;泡型包虫病表现为脑内多发等T1、短T2簇状异常信号,病灶周围通常有类似脑肿瘤样的水肿带.病灶T2WI信号似"煤炭样"黑色的低信号,内见无数密集稍高信号的小囊泡影,小囊泡直径约1～10 mm为其特征性表现.DWI序列病灶为低信号;Gd-DTPA增强扫描后病灶均见不规则的异常环形强化.2例脑灌注成像病变为低灌注改变.结论 MRI以多方位、多参数成像的优势显示脑包虫更准确,术前诊断率更高,对临床诊治具有重要意义.     

Cerebral hydatid disease CT and MR findings

In this study, we reviewed the computed tomography (CT, n=9) and magnetic resonance (MR, n=5) imaging findings of 11 patients with pathologically confirmed cerebral hydatid disease. Among our patients, there were 10 cases of Echinococcus granulosus and 1 case of Echinococcus multilocularis. Common CT and MR imaging findings of E. granulosus lesions were well-defined, smooth thin-walled, spherical, homogeneous cystic lesions with no contrast enhancement, no calcification, and no surrounding edema. E. multilocularis lesions showed calcified round, solid pattern with definite margins, contrast enhancement, and surrounding edema.     

Radiological assessment of mesenteric and retroperitoneal cysts in adults: is there a role for chemical shift MRI?

Objective

The purpose of this study was to assess the potential role for chemical shift magnetic resonance imaging (MRI) in identifying lymphangiomas from other cystic mesenteric and retroperitoneal masses.

Materials and methods

A retrospective search of radiology database identified 24 consecutive patients with mesenteric and retroperitoneal cysts (nine men, 15 women; mean age, 41 years; age range, 19-75 years) who had undergone MR which included in-phase and opposed-phase chemical shift imaging. Signal intensity (SI) decrease between in-phase and opposed-phase MR images of the cyst was evaluated qualitatively by two radiologists. Ultrasound (US), computed tomography (CT), and MRI findings of the morphological appearances of all the cystic lesions that demonstrated significant signal drop on chemical shift MR were also recorded.

Results

Of mesenteric and retroperitoneal cysts, 33% (8/24) revealed qualitative decrease in intensity on opposed-phase MR images relative to that seen on in-phase images. On ultrasound, these cysts demonstrated anechoic simple fluid. Their mean CT attenuation was 13 HU (range: 5-20 HU). Signal loss on fat-suppressed T1-weighted sequences was displayed only by a single cyst. None of the lesions with qualitative SI decrease on opposed-phase MR showed suggestion of lipid on US and CT.

Conclusion

The presence of intra cystic lipid detected by chemical shift MR may not be overt on cross-sectional imaging such as US and CT. Chemical shift MRI provides additional sensitivity and specificity as an imaging test for demonstration of lipid within mesenteric and retroperitoneal cysts enabling a higher diagnostic yield for lymphangioma leading to more appropriate patient management.     

Gynecologic and obstetric disorders presenting with abdominal pain

This article briefly reviews the clinical settings and imaging findings of gynecologic/obstetric disorders presenting with abdominal pain. MR imaging is considered to be an excellent modality for the diagnosis of these disorders because of its high sensitivity to blood. Although CT allows images to be obtained within a shorter time than does MR imaging, the possibility of pregnancy should be excluded prior to the examination. Hemorrhagic ovarian cyst exhibits hyperintensity on T1-weighted images or hematocrit effect on CT or MR images. Hemoperitoneum associated with hemorrhagic cyst strongly indicates rupture of the cyst. Rupture of endometrial cysts and dermoid cysts can cause acute chemical peritonitis. In ectopic pregnancy, findings of hematosalpinx associated with strong enhancement of the tubal wall frequently contribute to the diagnosis. Torsion of the adnexa can be diagnosed by the pedicle between the ovary and uterus, and the lack of contrast enhancement. Tuboovarian abscess is recognized as a cystic mass having a thick wall that is strongly enhanced. Among complications of uterine leiomyoma, red degeneration shows characteristic MR findings, hyperintense rim on T1-WI, hypointense rim on T2-WI, and lack of contrast enhancement. Because of the high incidence of OHSS associated with normal pregnancy, CT is contraindicated.     

肾包虫囊肿的CT诊断

目的 :探讨肾包虫囊肿及其破裂感染的CT表现及诊断意义。材料和方法 :本组 7例患者均行CT平扫与增强扫描 ,经手术病理或临床资料证实。结果 :3例单纯型囊肿 ,2例表现为肾实质内水样密度的囊性肿物 ,其边缘光滑 :4例多子囊型囊肿 ,内部含有多个更低密度子囊。 2例破裂 /感染型 ,其内外囊分离 ,1例囊腔内有塌陷折叠并且钙化的内囊膜 ;另 1例囊周水肿并增强。结论 :CT对肾包虫囊肿的定位和定性诊断、分型以及破裂感染的判断颇为准确 ,是目前诊断肾包虫囊肿安全可靠的检查方法     

Synovial cysts of the lumbosacral spine: diagnosis by MR imaging

Intraspinal synovial or ganglion cysts are uncommon lesions associated with degenerative lumbosacral spine disease. CT usually reveals cystic lesions adjacent to a facet joint, and they may show calcification. MR imaging of four surgically confirmed cases of intraspinal synovial cysts revealed subtle signal changes compared with CSF. Short TR/TE images showed the lesions to be slightly hyperintense in three cases and isointense in one case. Long TR/TE sequences revealed a hyperintense appearance in two cases and a hypointense appearance in the others. A peripheral rim of decreased signal on long TR/TE images probably reflects fine calcification or hemorrhage in the margins of the cysts. The multiplanar and contrast characteristics of MR make this technique well suited to the diagnosis of herniated disk, degenerative facet disease, and synovial cyst.     

Synovial cysts of the lumbosacral spine: diagnosis by MR imaging

Intraspinal synovial or ganglion cysts are uncommon lesions associated with degenerative lumbosacral spine disease. CT usually reveals cystic lesions adjacent to a facet joint, and they may show calcification. MR imaging of four surgically confirmed cases of intraspinal synovial cysts revealed subtle signal changes compared with CSF. Short TR/TE images showed the lesions to be slightly hyperintense in three cases and isointense in one case. Long TR/TE sequences revealed a hyperintense appearance in two cases and a hypointense appearance in the others. A peripheral rim of decreased signal on long TR/TE images probably reflects fine calcification or hemorrhage in the margins of the cysts. The multiplanar and contrast characteristics of MR make this technique well suited to the diagnosis of herniated disk, degenerative facet disease, and synovial cyst.     

肾上腺囊肿的CT、MRI诊断

目的:探讨肾上腺囊肿的CT、MRI表现,以提高诊断的准确率。方法:回顾性分析手术病理证实的9例肾上腺囊肿的CT、MRI表现。结果:9例肾上腺囊肿,5例行CT检查:1例呈圆形,2例呈椭圆形,2例呈分叶状。平扫囊肿密度均匀,CT值15~35HU,3例囊壁有钙化;增强扫描囊内均无强化,2例囊壁呈环形强化,3例囊壁无强化。4例行MR平扫:均呈长T1长T2异常信号,并且囊内可见分隔,分隔与液体相比呈短T1短T2异常信号,厚薄均匀,边缘光滑。结论:CT、MRI是肾上腺囊肿定位、定性诊断较为可靠和准确的方法。     

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.     

Primary adrenal lymphoma: radiological; pathological, clinical correlation

Objective

The purpose of this study was to analyze CT and MR imaging (MRI) manifestation of primary adrenal lymphoma in order to better understand of this rare disease.

Materials and methods

Six patients (4 men, 2 women; median age, 65.5 years) with pathologically proven primary adrenal lymphoma were retrospectively reviewed. Imaging findings (CT&;MRI, n = 3; only CT, n = 3) were analyzed and correlated with clinical and pathologic findings.

Results

All cases were pathologically proven primary adrenal diffuse large B-cell lymphoma with bilateral lesions in 3 cases respectively. Maximum diameters of the 9 lesions were 6.1–14.8 cm, median 10.5 cm. Seven lesions were round, oval or oblong, and 2 lesions irregular. Seven lesions were well-defined and 2 had ill-defined margins. Unenhanced CT density of 9 lesions and MR signal intensity of T1 weighted images of 6 lesions were similar to that of muscle, and all 6 lesions were hyperintense on T2-weighted MR images. Following intravenous injection of contrast media, 6 lesions had mild enhancement and 3 lesions had moderate enhancement on parenchymal phase imaging. Enhancement was homogenous in three, slightly inhomogeneous in four, and heterogeneous in two. Seven lesions, in 5 cases, infiltrated the adjacent tissues or organs in patients with large tumors.

Conclusion

Primary adrenal lymphoma usually manifests as large, well-defined, soft-tissue masses replacing the adrenal gland with homogeneous or slightly inhomogeneous enhancement. Large tumors especially tend to infiltrate adjacent structures.     

Tailgut cysts: MRI findings

Magnetic resonance imaging (MRI) features of 11 surgically resected pelvic tailgut cysts were analyzed with reference to histopathologic and clinical data. Homogeneity, size, location, signal intensity, appearance and presence of septa and/or nodules and/or peripheral rim and involvement of surrounding structures were studied. Histological examination demonstrated 11 tailgut cysts (TGC), including one infected TGC and one TGC with a component of adenocarcinoma. Lesions (3–8 cm in diameter) were exclusively or partly retrorectal in all cases but one, with an extension down the anal canal in five cases. Lesions were multicystic in all patients but one. On T1-weighted MR images, all cystic lesions contained at least one hyperintense cyst. The peripheral rim of the cystic lesion was regular and non or moderately enhancing in all cases but the two complicated TGC. Nodular peripheral rim and irregular septa were seen in the degenerated TGC. Marked enhancement of the peripheral structures was noted in the two complicated TGC. Pelvic MRI is a valuable tool in the preoperative evaluation of TGC.     

Primary soft tissue hydatid disease: report of two cases with MRI characteristics

Hydatid disease of the soft tissues forms a rare mass lesion of the extremities. Two cases of primary hydatid disease in soft tissues are presented with MR imaging findings. A cystic mass with multiloculated or multicystic appearance was identified on MR images in both cases. The lesions were surrounded by a rim with two layers representing a collageneous and a vascularized pericyst. The contrast-enhanced images demonstrated the vascularized component of the wall clearly in the first case. In diagnosis of hydatid disease and in its differentiation from other cystic lesions of the extremities, we think that the described MR appearances can be used confidently. Received: 8 April 1998; Revision received: 20 July 1998; Accepted: 24 August 1998     

颈部囊性病变的多排螺旋CT和MRI影像学特征分析

目的：分析颈部囊性病变的多排螺旋CT和MRI影像学特征。方法回顾性分析41例经病理证实的颈部囊性病变的解剖部位及多排螺旋CT和MRI影像学征象。结果颈部囊性病变多形状规则,边界清晰。20例甲状舌管囊肿位于正中线舌骨水平或略偏,与甲状软骨关系密切,MRI征象为长 T1长 T2信号,信号均匀,增强扫描囊壁轻度强化;11例第二腮裂囊肿位多于胸锁乳突肌前内侧,MRI为囊性长T1长T2信号,信号均匀,囊肿内CT值为水样密度,增强扫描囊壁轻度强化;2例表皮样囊肿位于颈中线舌骨水平、颈后部,CT扫描密度均匀,增强未见明显强化;4例会厌囊肿位于会厌前间隙内,MRI影像为囊性长T1长T2信号肿块,信号均匀,CT影像为囊性薄壁低密度肿块,密度均匀;4例淋巴管瘤主要位于颈后三角区,MRI肿块呈等T1长T2信号,内部可见分隔,囊腔大小不等,增强扫描其分隔可见强化。结论颈部不同囊性病变的解剖位置和影像学征象有一定的特点,经过综合分析,可以做出正确诊断。     

脊柱包虫病的MRI诊断（附三例报告）

作者报告３例经手术证实的脊柱包虫囊肿的ＭＲＩ表现，其特征性表现为：（１）卵圆形或圆形水样信号囊肿；（２）母囊内有子囊；（３）连续低信号囊壁；（４）囊膜分离征。还对本病的诊断和鉴别诊断进行了扼要的讨论。     

纵隔棘球蚴病的CT表现

目的:探讨纵隔棘球蚴病的CT表现。方法:回顾性分析10年以来的5例纵隔棘球蚴囊肿的CT影像特点。结果:5例病灶为圆形或椭圆形囊性肿块,壁略厚。2例病灶为单囊型,其中1例病灶囊肿壁钙化;3例病灶为多囊型,其中2例病灶囊肿壁有钙化。增强扫描棘球蚴囊肿壁均强化明显。结论:CT对纵隔棘球蚴病定位、定性有较高的诊断价值。