MR appearance and cyst content of Rathke cleft cysts

The magnetic resonance signal intensity and cyst content were analyzed in 2 new and 17 previously reported cases of Rathke cleft cyst. Lesions displaying hypointensity on T1-weighted images (T1WI) and hyperintensity on T2-weighted images (T2WI) contained CSF-like fluid. Cases showing hyperintensity on T1WI and isointensity on T2WI frequently contained mucoid material. Hyperintensity on both T1WI and T2WI suggests the presence of blood. A small area of hypo- or isointensity indicates thickening of the cyst wall or collection of cellular debris.     

Rathke cleft cysts: correlation of enhanced MR and surgical findings.

PURPOSETo describe the gadolinium-enhanced MR findings of Rathke cleft cyst correlate them with the surgical findings, and define those preoperative findings that differentiate this lesion from other sellar and juxtasellar tumors.METHODSWe studied 18 patients who were diagnosed as having Rathke cleft cyst pathologically. These patients were imaged with T1- and T2-weighted coronal and sagittal spin-echo sequences. Fifteen of these patients received gadopentetate dimeglumine.RESULTSIn eight patients, the cyst showed low intensity on T1-weighted images and high intensity on T2-weighted images. At surgery, the cyst fluid was cerebrospinal fluid-like or light brown in five patients, motor oil-like in one patient, and milky in two patients. In 10 patients, cysts showed isointensity to high intensity on T1-weighted images and had various intensity on T2-weighted images. All 10 contained milky fluid. In three patients the intensity of fluid was heterogeneous. A waxy nodule was found in two patients. The position of the normal pituitary gland confirmed by surgery in all cases coincided with enhancement on MR imaging. The variable position of the normal pituitary gland was clearly identified in the sagittal images. The cyst walls showed no enhancement by gadopentetate dimeglumine.CONCLUSIONSBecause Rathke cleft cysts show variable intensities on MR, the diagnosis is often difficult when based on MR signal intensity values alone. MR imaging with gadopentetate dimeglumine does assist in the diagnosis of Rathke cleft cysts. Diagnostic clues include the lack of cyst wall enhancement and displacement of the normal pituitary gland.     

Anorectal gastrointestinal stromal tumors: CT and MR imaging features with clinical and pathologic correlation

OBJECTIVE: The purpose of this study was to describe the imaging features of anorectal gastrointestinal stromal tumors with clinical and pathologic correlation. CONCLUSION: Anorectal gastrointestinal stromal tumors are mesenchymal neoplasms that typically arise in the muscularis propria of the intestinal wall. The cross-sectional imaging appearance is that of a well-defined mural mass that may have an exophytic component and may invade adjacent structures. A prominent intraluminal component is a rare feature.     

Rathke cleft cyst: MR and biomedical analysis of cyst content

PURPOSE: At least one type of Rathke cleft cyst has unique MR findings, specifically, high intensity on T1-weighted images and iso- to low intensity on T2-weighted images relative to white matter. To clarify the influence of cyst content on MR images, we analyzed the cyst content by biomedical methods after surgical removal. METHOD: We studied five patients diagnosed with Rathke cleft cyst, whose MR images showed high intensity on T1-weighted images and iso- to low intensity on T2-weighted images. After surgery, total protein and cholesterol levels were quantified, and correlations of protein and cholesterol content with T1 and T2 signal intensities were performed in vitro. RESULTS: All five cysts had very high concentrations of protein (11,700-26,600 mg/dl, mean 17,940 mg/dl) with nearly no cholesterol (at most 2.0 mg/dl). Along with increases in protein concentration in vitro, the signal intensity of T1-weighted images increased, while that of T2-weighted images decreased. In contrast, the cholesterol concentration sequence influenced the signal intensity of neither T1- nor T2-weighted images. CONCLUSION: The unique MR finding of Rathke cleft cysts--high signal intensity on T1-weighted images and low signal intensity on T2-weighted images--might depend mainly on protein concentration, not on cholesterol.     

Computed tomography in intra- and suprasellar epithelial cysts (symptomatic Rathke cleft cysts)

The computed tomographic (CT) and pathologic findings in three cases of intra- and suprasellar epithelial cysts (symptomatic Rathke cleft cysts) are described. Literature review revealed that the characteristic CT finding is an intrasellar and/or suprasellar low-density mass that may or may not be enhanced. The enhancement is ringlike or capsular in nature. Whether the cyst wall is enhanced or not seems to be dependent on the histologic features. It is suggested that the enhancement may be caused by an inflammatory process, either septic or aseptic, or squamous metaplasia in the wall, which is possibly induced by degeneration or infection of the cyst contents. Without these additional pathologic processes, the Rathke cleft cyst, a simple retention cyst, may exhibit no contrast enhancement.     

Nocardial endophthalmitis and subretinal abscess: CT and MR imaging features with pathologic correlation: a case report

Ocular nocardiosis is a rare but potentially aggressive process. Clinically, it can mimic other disease entities, including neoplasia and other types of infection. We present a case of nocardial panophthalmitis progressing to subretinal abscess and emphasize the radiologic and clinical features.     

子宫腺肌症的MRI表现及其病理学对照研究

目的：研究MRI在子宫腺肌症诊断中的应用价值。方法：对30例子宫腺肌症患者行矢状面快速自旋回波（Turbo SE)T1WI,T2TI,T1和T2频谱预饱和翻转恢复序列（T1SPIR和T2SPIR）扫描，必要时辅以横断面或冠状面扫描。所有病例均经手术病理证实。结果：弥漫型子宫腺肌症12例，在T2WI上表现为子宫结合带弥漫性增厚，厚度10－35mm，平均18mm，6例病变呈均匀低信号；6例病变内有散在的点高信号区，其中5例在T1WI仍表现为高信号。局限型子宫腺肌症（腺肌瘤）18例共23个病灶，在T2WI上表现为肌层内卵圆形，不规则形或类圆形肿块，呈与结合带信号相近的低信号，直径2．0－7.5cm，平均3.9cm，除1个病灶与周围肌组织有较清楚的界限外，其余病灶均与周围肌组织分界不清，15个病灶内有散在点状高信号区，其中12个在T1WI上也呈高信号，MRI上弥漫增厚的结合带和局限性低信号肿块，病理学上为异位内膜岛周围增生肥大的平滑肌，其内散在的点状信号区异异位内膜岛。仅在T2WI表现高信号的为示出血的内膜岛，在T1WI和T2WI均为高信号的为出血的内膜岛。结论：MRI是诊断子宫腺肌症的优越的无创性检查方法，T2WI最佳扫描序列，T2WI与T1WI，T1SPIR，T2SPIR4种序列相结合可大大提高断诊准确率。     

MR imaging findings of Rathke's cleft cysts: significance of intracystic nodules

BACKGROUND AND PURPOSE: Rathke's cleft cysts often may be difficult to differentiate from other intrasellar or suprasellar masses on radiologic studies. The purpose of this study was to describe the significance of intracystic nodules, a diagnostic characteristic found in Rathke's cleft cysts, on MR images. METHODS: A retrospective review of MR studies was conducted for 13 patients who, after pathologic analysis, were diagnosed as having Rathke's cleft cyst. These patients underwent unenhanced and contrast-enhanced T1- and T2-weighted axial and coronal spin-echo sequential imaging. The signal intensity and incidence of the intracystic nodules on T1- and T2-weighted images were analyzed. The signal intensity of the nodule was compared with that of white matter and surrounding cyst fluid. The signal intensity of cyst fluid was compared with the intraoperative appearance of the cyst fluid. Biochemical and pathologic analyses of the intracystic nodules were conducted in two cases. RESULTS: An intracystic nodule having high signal intensity on T1-weighted images and low signal intensity on T2-weighted images was observed in 10 (77%) of the cases. At surgery, intracystic nodules were yellow, waxy, solid masses. Pathologic analysis showed this nodule to be a mucin clump. Biochemical analysis of the intracystic nodules showed cholesterol and proteins as the main constituents. In the Rathke's cleft cyst with intracystic nodules, cyst fluid revealed low signal intensity to isointensity relative to the intensity of the nodules on T1-weighted images, and isointensity to high signal intensity on T2-weighted images. Intracystic nodules were clearly visible on T2-weighted images. CONCLUSION: Because cyst fluid of Rathke's cleft cysts shows variable intensities on MR images, the specific diagnosis is often difficult when based on MR signal intensity values alone. The presence of an intracystic nodule with characteristic signal intensities on MR images may be indicative of the diagnosis of Rathke's cleft cyst.     

节细胞神经瘤的影像学表现

目的 探讨节细胞神经瘤的CT和MR表现.方法 回顾性分析18例经手术病理证实的节细胞神经瘤的CT、MR影像学资料,所有患者均接受CT平扫及增强扫描,2例接受MR平扫.结果 节细胞神经瘤好发于中青年,位于后纵隔8例,肾上腺5例,腹膜后4例,颈部1例.均为单发病灶、边界清楚,嵌入式生长可呈多种形态.CT平扫:12例为均匀低密度,平均CT值22～37 HU;6例密度不均,平均CT值13～46 HU,其中2例伴有坏死、囊变.2例见斑点状钙化.增强扫描:肿瘤各期均无强化4例,仅动脉期轻度强化5例,仅静脉期轻度强化2例,静脉期及延迟期呈轻、中度渐进性强化1例,三期呈渐进性强化6例;坏死及囊变部分未见强化.2例肿瘤内见肋间后动脉穿行,1例见腰动脉穿行并见细小分支滋养肿瘤.2例下腔静脉推挤受压移位,1例见颈部大血管被包绕.MR平扫:1例信号均匀,1例信号不均;T1WI表现为低信号,T2 WI呈高信号为主,脂肪抑制(SPIR)及扩散加权成像(DWI)呈高信号.结论 节细胞神经瘤的CT及MR表现具有一定特征性,尤其是CT示肿瘤为均匀低密度、伴有斑点状钙化、肿瘤内血管穿行但未受侵,增强扫描动脉期无明显强化或轻度强化,呈渐进性强化方式,DWI示肿瘤呈高信号时,应考虑节细胞神经瘤的可能.     

Degenerative thalamic hamartoma: CT and MR imaging features

We describe hamartomas of possible thalamic origin. CT revealed marked calcification in the mass lesion, and MR imaging revealed contrast enhancement. Histologically, outgrowth of the glia was observed, but no neoplastic component was confirmed. Immunohistochemical staining was positive for the cell-adhesion factor N-CAM and negative for polysialic acid.     

Juxtaacetabular ganglionic (or synovial) cysts: CT and MR features

Radiographic findings include supraacetabular bone erosions, subchondral acetabular cysts, soft tissue masses with or without radiolucent inclusions representing nitrogen gas, joint space narrowing, and abnormal hip configuration. Associated tears of the acetabular labrum were confirmed by arthrography in two patients. Computed tomography and magnetic resonance imaging afforded improved delineation of soft tissue ganglia and their relationship to the acetabular bone, labrum, and hip joint. We report our experience with seven patients in whom various imaging examinations clearly documented the presence of soft tissue cystic lesions adjacent to the acetabulum; in six of the seven patients, significant clinical manifestations were evident in the affected hip. Such cysts, whether designated synovial or ganglionic in type, appear to be a frequently overlooked yet important cause of hip symptomatology.     

Pancreatic mass due to chronic pancreatitis: correlation of CT and MR imaging features with pathologic findings.

OBJECTIVE: The purpose of this study was to identify helical CT and MR imaging features of pancreatic masses (focal enlargement) due to chronic pancreatitis and their correlation with pathologic findings. CONCLUSION: When histologic fibrosis is uniformly present through the pancreas in patients with chronic pancreatitis, there is no demarcation of masses due to chronic pancreatitis. When there is a greater degree of histologic fibrosis in the masslike part of the pancreas, the mass is often demarcated from the remaining pancreas, and the enhancement pattern on two-phase helical CT and dynamic gadolinium-enhanced MR imaging mimics that of pancreatic adenocarcinoma.     

Brachial plexus: correlation of MR imaging with CT and pathologic findings

Thirty-two patients with symptoms referable to the brachial plexus were evaluated with magnetic resonance (MR) imaging. Sixteen patients had undergone concurrent computed tomography (CT). MR imaging demonstrated normal findings in 16, 12 neoplasms, three cases of trauma, and one case of possible neural edema. Of the 16 patients with normal findings on MR images, eight had CT scans that were also normal. In one patient, MR images showed that the "mass" seen on CT was actually a tortuous blood vessel. In six of the 12 cases of neoplasm in which CT scans were available, MR imaging revealed more extensive disease. In the other six cases of tumor, MR imaging provided sufficient clinical information to obviate the need for CT or any other imaging modality. MR imaging provided definitive diagnoses in the three cases of trauma without further imaging. In one patient with paresthesia, MR imaging showed high signal intensity of the nerves on T2-weighted images, which was compatible with neural edema. A concurrent CT scan was normal.     

Epidermoid cysts of the testicle: sonographic and MR imaging features.

OBJECTIVE: The purpose of this study is to analyze the appearance of testicular epidermoid cysts on high-resolution sonography and MR imaging and correlate imaging features with histopathologic findings. CONCLUSION: Intratesticular epidermoid cysts may show imaging features that correlate with their histopathologic findings. Concentric rings of alternating hypo- and hyperechogenicity on sonography and alternating high and low signal intensity on MR imaging ("onion ring" appearance) correspond to the pathologic finding of multiple layers of keratin debris. Absence of flow on color Doppler sonography and absence of contrast enhancement on MR imaging is also consistent with the avascular nature of these lesions. The ability of preoperative imaging studies to suggest the diagnosis of epidermoid cyst may prompt a testis-sparing surgery instead of an orchiectomy.     

Intra-articular ganglion cysts of the knee: clinical and MR imaging features

The purpose of this study was to present clinical and MR imaging features of intra-articular ganglion cysts of the knee. Retrospective review of 1685 consecutive medical records and MR examinations of the knee performed at three imaging centers allowed identification of 20 patients (13 men and 7 women; mean age 35 years), in whom evidence of intra-articular ganglion cyst was seen. Of the 20 ganglion cysts, 5 were found in the infrapatellar fat pad, 10 arose from the posterior cruciate ligament, and 5 from the anterior cruciate ligament. Three of five patients with ganglion cyst in the infrapatellar fat pad had a palpable mass. In 7 of 15 patients with ganglion cyst in the intercondylar notch, exacerbation of pain occurred in a squatting position. On four MR arthrographies, ganglion cysts were an intra-articular round, lobulated, low signal intensity lesion. Five cases of fat-suppressed contrast-enhanced T1-weighted SE images demonstrated peripheral thin rim enhancement. The clinical presentation of intra-articular ganglion cyst is varied according to its intra-articular location. The MR appearance of intra-articular ganglion cyst is characteristic and usually associated with the cruciate ligament or the infrapatellar fat pad. Magnetic resonance arthrography has no definite advantage over conventional MR in the evaluation of the lesion. For intra-articular ganglion cyst in the infrapatellar fat pad, fat-suppressed contrast-enhanced MR imaging could be useful, because a thin, rim-enhancing feature of intra-articular ganglion cyst allows it to be distinguished from synovial hemangioma and synovial sarcoma. Received: 29 June 2000 Revised: 13 September 2000 Accepted: 15 September 2000     

Orbital tumors in children: CT and MR imaging features

The purpose of the article is to review the CT and MR imaging features of orbital tumors in children. Tumors in children are usually different than those in adults. Clinical symptoms are usually non-specific. Clinical examination combined with US may be sufficient for diagnosis and follow-up of benign and superficial lesions. CT and/or MRI are needed for deep or malignant lesions. CT is valuable for osseous and/or calcified lesions. MR is advantageous because of its superior spatial resolution and non-ionizing nature. Malignant tumors correspond to about 20% of lesions and include primary tumors (retinoblastoma, rhabdomyosarcoma) and metastases. Benign pathology is more frequent (80%) with dermoid cyst corresponding to about 50% of orbital masses.     

Mediastinal lymphangioma in adults: CT and MR imaging features

Adult mediastinal lymphangiomas are rare lesions the diagnosis of which is difficult based on imaging studies. A retrospective study of CT, MR, and pathologic findings of mediastinal lymphangioma was performed in order to correlate pathological and imaging findings. Nine cases of adult lymphangiomas were identified in the records of our institution over a 12-year period. The CT, MR, and pathologic findings were reviewed. Lesions were classified pathologically as unilocular, cavernous, and intermediate types. Pathologic examination identified six cases of unilocular lesion, two cases of cavernous type, and one intermediate type. The CT features (n = 9) included a smoothly marginated non-enhancing mass of water attenuation (n = 7), a non-enhancing mass of soft tissue attenuation (n = 1), and an enhancing multiseptated mass (n = 1). Lesions were located in the anterior mediastinum (n = 2), right paratracheal (n = 4), subcarinal (n = 1), aortopulmonic window (n = 1) areas, and below the left hilum extending into the posterior mediastinum (n = 1). The MR features (n = 3) were characterized by an enhancing multicystic and multiseptated appearance, evocative of a cavernous type in two cases. The CT appearance of mediastinal thoracic lymphangioma is variable depending on the pathologic type. The most common unilocular type is a non-enhancing thin-walled mass on CT. A less frequent cavernous type can be suggested based on a multiseptated and loculated mass on CT and/or MR examination. Received: 21 June 1999; Revised: 30 September 1999; Accepted: 23 February 2000