Lymphocytic adenohypophysitis: skull radiographs and MRI

We report the skull radiograph, CT and MRI findings in three patients with lymphocytic adenohypophysitis mimicking pituitary adenoma. All cases were associated with pregnancy. CT demonstrated a pituitary mass but did not differentiate lymphocytic adenohypophysitis from pituitary adenoma. The skull radiographs showed either a normal sella turcica or minimal abnormalities; they did not show ballooning or destruction. The MRI appearances were distinctive: relatively low signal on T1-weighted images; preservation of the bright posterior pituitary lobe despite the presence of a relatively large pituitary mass, less common in macroadenomas; marked contrast enhancement compared with pituitary macroadenomas; and dural enhancement adjacent to a pituitary mass. Received: 12 December 1996 Accepted: 19 June 1997     

Abnormal perfusion of the pituitary gland secondary to dural arteriovenous fistulas in the cavernous sinus: dynamic MR findings

BACKGROUND AND PURPOSE: If venous congestion is the primary cause of pituitary gland enlargement in cases of dural arteriovenous fistulas (AVFs), other abnormal pituitary findings may be detectable on MR images. We sought to investigate the perfusion abnormality of the pituitary gland secondary to dural AVFs in the cavernous sinus and to clarify its clinical importance. METHODS: Nine consecutive patients (all female; age range, 50-77 years) with dural AVFs in the cavernous sinus underwent prospective MR examinations, including dynamic studies, before and after therapy. Their clinical signs and symptoms were recorded. Two radiologists visually evaluated the enhancement patterns of the anterior pituitary gland. Dynamic MR curves were obtained by locating regions of interest at the center and bilateral peripheral areas of the anterior pituitary gland on coronal images. MR images obtained in five healthy individuals served as controls. RESULTS: No patient had symptoms of hypopituitarism or other endocrine abnormalities. Asymmetric pituitary enhancement was found in five patients; the side with the dural AVF was less enhancing. This finding disappeared after therapy. Although asymmetric enhancement was not detected in the remaining four patients, statistical analysis showed significantly delayed enhancement of the pituitary gland in the patients compared with enhancement patterns in control subjects. After treatment, this delay improved significantly. The pituitary gland significantly decreased in size after treatment. CONCLUSION: Perfusion of the pituitary gland is impaired in patients with a dural AVF in the cavernous sinus. This finding is probably due to venous congestion of the pituitary gland caused by high pressure in the cavernous sinus; it is usually not related to pituitary dysfunction.     

MR imaging of cavernous sinus involvement by pituitary adenomas

The ability of high-resolution MR imaging (1.5 T) to detect invasion of the cavernous sinuses by pituitary adenoma was determined through a retrospective review of 74 patients. These patients were divided into three groups: 25 normal subjects, 24 subjects with invasive pituitary adenomas, and 25 subjects with noninvasive pituitary adenomas. A fourth group of 30 patients, who subsequently underwent surgery for pituitary adenoma, was evaluated prospectively by MR for the presence or absence of cavernous sinus invasion. Several features were analyzed: (1) the detectability of the medial and lateral dural margins of the cavernous sinus (2) the size and variation in intensity of compartments within the cavernous sinus (3) the relationship of endocrine function to the surgical and MR appearance of the cavernous sinus and (4) carotid artery displacement or encasement by tumor. The normal cavernous sinuses were usually symmetric, but their sizes varied. The lateral dural margin of the cavernous sinus was always recognized on MR as a linear, discrete, low-intensity area. The medial dural margin (pituitary capsule) was seen on MR in only two of the 25 normal patients. In all 24 patients with cavernous sinus invasion involvement was unilateral and was most common with laterally positioned prolactin or adrenocorticotropic hormone secretory adenomas. Invasion of the cavernous sinus was suspected by MR in only two of the 13 invasive microadenomas and was questionable in three. In 10 of the 11 macroadenomas with surgically proved dural invasion, MR demonstrated an asymmetric increase in size and intensity of the superior and inferior cavernous sinus compartments. Noninvasive macroadenomas compressed and displaced the cavernous sinus bilaterally. The prospective MR evaluation of 30 patients undergoing surgery for pituitary tumor revealed a sensitivity for predicting cavernous sinus invasion of 55%, a specificity of 85.7%, a positive predictive value of 62.5%, and a negative predictive value of 81.8%. No feature permitted certain distinction between invasive and noninvasive microadenomas, as the medial dural wall of the cavernous sinus could not be reliably identified. The most specific sign of cavernous sinus invasion was carotid artery encasement.     

Gd-DTPA-enhanced MR imaging of pituitary macroadenomas.

In a study comprising 40 patients with pituitary macroadenomas, MR imaging was performed before and after administration of Gd-DTPA. Before contrast administration T1- and T2-weighted images were obtained, and after the injection, frontal and/or sagittal T1-weighted images. Tumour extension and delineation, relationship to adjacent structures, and signal intensity patterns were evaluated. Compared with pre-contrast T1-weighted images only, post-contrast images provided considerable additional information, but not infrequently this information could also be extracted from pre-contrast T2-weighted images. Post-contrast images were superior regarding the tumour relationship to the cavernous sinus and to the normal pituitary tissue. T2-weighted images were helpful in the diagnosis of degenerative changes, in particular intratumoural haemorrhage. A positive correlation was found between the T2 value (from dual echo sequences) and the degree of enhancement in areas with an appearance of solid tumour tissue, and the enhancement was significantly lower in GH-secreting tumours than in non-secreting ones. It is concluded that the use of Gd-DTPA is often justified in pituitary macroadenomas, particularly in pre-operative evaluation.     

Preoperative location of the pituitary bright spot in patients with pituitary macroadenomas

BACKGROUND AND PURPOSE: The purpose of this study was to determine the location of the pituitary bright spot in patients with pituitary macroadenomas before surgery. METHODS: A total of 54 patients with pituitary macroadenomas were retrospectively included in this study. Nonenhanced spin-echo T1-weighted MR images were reviewed to identify the location of the high-intensity-signal posterior pituitary lobe that indicates antidiuretic hormone (ADH) storage. Images were acquired with a 1.5-T machine by using 3-mm-thick contiguous sections in two or three orthogonal planes and a 300 x 512 matrix. RESULTS: The bright spot corresponding to ADH storage was identified in 44 (81%) patients. Two groups of patients were defined by the height of the macroadenoma: Group A patients (n = 27) had pituitary macroadenomas less than 20 mm in height, and group B (n = 27) had macroadenomas 20 mm or larger. In group A, the bright spot was identified in 25 patients (93%); it was located in the sella in 24 of these cases (96%). In group B, the bright spot was identified in 19 patients (70%); it was in an ectopic location in 14 of these cases (74%). CONCLUSION: MR imaging can be used to depict the pituitary bright spot in most patients with pituitary macroadenomas before surgery. The bright spot is usually identified at its expected location within the sella in patients with pituitary macroadenomas less than 20 mm in height, whereas an ectopic location is common when pituitary macroadenomas are larger more than 20 mm.     

Normal and abnormal pituitary glands: gadopentetate dimeglumine-enhanced MR imaging

Dynamic magnetic resonance (MR) imaging with a 1.5-T superconductive unit was used in the evaluation of nine normal pituitary glands and 10 pituitary adenomas, including four microadenomas and six macroadenomas. Seven to 10 images were obtained every 20-30 seconds with use of the spin-echo technique after rapid injection of gadopentetate dimeglumine. The earliest contrast material enhancement of normal structures was seen in the infundibulum and posterior lobe of the pituitary gland at 20 seconds, followed by gradual contrast material enhancement of the anterior lobe of the pituitary gland from the junction of the infundibulum to the peripheral portion of the anterior lobe of the pituitary gland within 80 seconds after gadopentetate dimeglumine injection. The peak enhancement of pituitary adenomas occurred at 60-200 seconds, usually after the most marked enhancement of the normal pituitary gland. Microadenomas are best visualized at earlier phases of gadopentetate dimeglumine-enhanced dynamic imaging, with signal intensity lower than that seen on images of normal pituitary glands.     

Dural tail sign in spinal meningiomas

OBJECTIVE: To study the association between the "dural tail sign" and spinal meningiomas on MR imaging. METHODS: Retrospective review of MR examinations of all pathologically proven spinal meningiomas from 1998 to 2005 was performed. Lesions were evaluated for size, signal intensity, enhancement pattern, and presence or absence of dural tail. The dural tail length and direction in reference to the meningioma were also evaluated. RESULTS: Seven spinal meningiomas were identified in seven patients. One lesion was purely extradural, while the remaining were intradural extramedullary. Dural tail was present in four cases (57%) and its length ranged between 5 and 21 mm. The tail was seen cranial and caudal to the meningioma in three cases and only cranially in one. Coronal images were available in three cases and in two of these; the dural tail was clearly depicted. CONCLUSIONS: "Dural tail sign" is as common in spinal meningiomas as in cranial meningiomas.     

腰椎后缘软骨结节的CT诊断与分型

目的：探讨ＬＰＭＮ的好发部位和对硬膜囊、神经根的影响。材料和方法：回顾性分析１４９例ＬＰＭＮ的ＣＴ表现、好发部位及其原因，重点讨论ＬＰＭＮ对硬膜囊和神经根的影响。结果：根据ＬＰＭＮ的部位将其分为四型：（１）上缘后正中型（４６．１％），易压迫硬膜囊和双侧或单侧神经根。（２）上缘后外侧型（２４．６％），主要引起同侧神经根受压，同时也易压迫硬膜囊外前部。（３）下缘后正中型（２６．３％），主要造成硬膜囊受压。（４）下缘后外侧型（３．０％），易压迫硬膜囊和同侧脊神经。结论：ＣＴ能清楚显示ＬＰＭＮ的改变及其对硬膜囊和神经根的影响，是ＬＰＭＮ最理想的检查方法。     

Tentorial enhancement on MR images is a sign of cavernous sinus involvement in patients with sellar tumors

BACKGROUND AND PURPOSE: This study was undertaken to analyze enhancement patterns of the dura around sellar tumors and to compare the results with tumor invasion or compression of the cavernous sinuses. Postoperative enhancement patterns on MR images were compared with preoperative findings. METHODS: Contrast-enhanced coronal and sagittal MR images were examined prospectively in 96 patients with sellar tumors (65 macroadenomas, 15 microadenomas, 14 Rathke cleft cysts, and two chordomas at the sella). All patients underwent surgical treatment, and pre- and postsurgical features on MR images were compared. RESULTS: Presurgical MR images showed dural enhancement in 36.5% of the patients: asymmetric tentorial enhancement in 24 patients, symmetric tentorial enhancement in seven, and sphenoidal ridge or clivus enhancement in four. Asymmetric tentorial enhancement disappeared after surgical decompression in seven patients. For evaluation of cavernous sinus invasion ipsilateral to the enhancement, sensitivity and specificity of the asymmetric tentorial enhancement sign were 81.3% and 86.3%, respectively. Sensitivity and specificity of the sign were 42.9% and 93.6% for cavernous sinus involvement, including compression and invasion. CONCLUSION: Asymmetric tentorial enhancement is a useful sign in the diagnosis of invasion or severe compression of the cavernous sinus by sellar tumor. The sign may represent venous congestion or collateral flow in the tentorium due to obstructed flow in the medial portion of the cavernous sinus.     

非脑膜瘤脑膜异常强化的MRI与病因对比研究

目的：分析不同脑膜病变的强化特征，探讨脑膜强化形式与病因诊断的关系。材料与方法：回顾性分析资料完整的异常脑膜强化２６例，根据脑膜受累层次、范围将强化形式分为四种：（１）弥漫性脑膜强化；（２）弥漫性硬膜强化；（３）弥漫性软膜强化；（４）局限性硬膜强化。依病因不同将脑膜病变分为三组：（１）肿瘤组；（２）炎症组；（３）反应组。结果：２６例中，肿瘤组８例，其中弥漫性硬膜、软膜强化各３例，弥漫性脑膜强化、局限性硬膜强化各１例。炎症组８例，弥漫性软膜强化７例，局限性硬膜强化１例。反应组１０例，８例呈局限性硬膜强化，２例呈弥漫性硬膜强化。结论：不同的脑膜病变可表现不同的强化特征，但离开临床，仅根据强化特征尚难做出定性诊断。     

Dural enhancement with primary calvarial lesions

The purpose of this study was to relate the pathological and imaging features of dural enhancement and meningeal sign (dural tail) on contrast-enhanced T1-weighted magnetic resonance (MR) images from patients with primary calvarial lesions as well to assess the accuracy of MR imaging in predicting dural invasion. Thirty-two calvarial tumors studied with contrast-enhanced MR imaging and histopathological examination of the dural specimens were reviewed. Sixteen patients presented dural enhancement, eight with tumor invasion. Tumoral invasion of the dura was observed in one case without enhancement. Malignant lesions showed enhanced dura more commonly than benign lesions (P=0.02). Nodular and discontinuous dural enhancement was statistically associated with dural invasion (P=0.05). Dural tail did not show a specific pathological association. Meningeal enhancement is a nonspecific reaction to calvarial lesions unless nodular and discontinuous. False-negative and -positive cases of dural invasion imply some limitation of contrast-enhanced MR imaging in predicting dural invasion by calvarial neoplasms.     

Idiopathic granulomatous hypophysitis: clinical and imaging features

Idiopathic pituitary granuloma is a rare disorder similar to lymphocytic adenohypophysitis. Few cases have been reported. We report a new histologically case proven with MRI. The patterns of clinical and radiological presentation and the management of this disorder are discussed. MRI findings suggestive of this condition include an intensely enhancing pituitary mass, associated with dural enhancement. Steroid therapy may be suggested avoiding unnecessary surgery.     

鞍结节脑膜瘤与向前上生长的垂体腺瘤MRI鉴别诊断

目的 探讨鞍结节脑膜瘤与向前上生长的垂体大腺瘤的影像学鉴别要点。资料与方法 分析17例经手术证实的鞍结节脑膜瘤的MRI征象,并与同期病理确诊的14例垂体大腺瘤进行对照。结果 17例脑膜瘤：均显著强化,包绕颈内动脉13例,长脑膜尾征14例、瘤周较多流空信号5例,蝶鞍扩大9例,垂体柄不能辨认11例,肿块与垂体分界不清7例,无腰征。14例垂体大腺瘤：7例显著强化、但不均匀,颈内动脉包绕14例,短脑膜尾征9例,较多流空信号2例,蝶鞍扩大14例,垂体柄不能辨认14例,见不到垂体结构13例,腰征12例。鞍结节脑膜瘤的瘤体显著及均匀强化、脑膜尾征粗大、瘤内星状改变均明显不同于垂体大腺瘤,其中长脑膜尾征、明显及均匀强化价值最大。结论 长脑膜尾征和肿瘤明显及均匀强化、无腰征是鞍结节脑膜瘤的特征性表现,对于鉴别鞍结节脑膜瘤与向前上生长的垂体大腺瘤具有重要价值。     

MRI of pituitary adenomas: the position of the normal pituitary gland

The position of the normal pituitary gland, assessed using gadolinium-enhanced MRI was compared with the position found at surgery for pituitary adenoma in 25 patients. The tumours were five microadenomas and 20 macroadenomas. Using T1-weighted imaging, the anterior lobe could be differentiated on the sagittal image in five patients (20%) and on the coronal image in four (16%). The high intensity of the posterior lobe could be differentiated using T1-weighted sagittal imaging in 13 patients (52%). The normal pituitary gland, which enhanced more strongly than tumour, could be differentiated using Gd-DTPA-enhanced MRI on the sagittal images in 22 cases (88%) and on the coronal image in 17 (68%). In seven patients, the normal pituitary gland surrounded the tumour; it was displaced superiorly in 14 cases and superioposterorly in two but in no case was it displaced anteriorly or downwards.     

Evaluation of pituitary adenomas by multidirectional multislice dynamic CT

Purpose:
Multidetector-row CT is a new technology with a short scanning time. Multislice dynamic CT (MSDCT) in various directions can be obtained using the multidetector-row CT with multiplanar reformatting (MPR) technique. Material and Methods:
We evaluated the initial results of sagittal and coronal MSDCT images reconstructed by MPR (MSDCT-MPR) in 3 pituitary adenoma patients with a pacemaker. Results:
In a patient with microadenoma, the maximum contrast between the normal anterior pituitary gland and the adenoma occurred approximately 50 s after the start of the contrast medium injection. A microadenoma was depicted as a less enhanced area relative to normal pituitary tissue. The macroadenomas were depicted as a less enhanced mass with cavernous sinus invasion in 1 patient and as a non-uniformly enhanced mass in another patient. Bone destruction and incomplete opening of the sellar floor during previous surgery were clearly detected in 2 patients with macroadenomas. These pituitary adenomas were removed via the transnasal route based on information from the MSDCT-MPR images only. The findings were verified surgically. Conclusion:
The MSDCT-MPR provided the information needed for surgery with good image quality in the 3 patients with pacemakers. MSDCT-MPR appears to be a useful technique for patients with a pituitary adenoma in whom MR imaging is not available. This is the first report, to our knowledge, of the MSDCT-MPR technique being used to demonstrate pituitary disorders.     

Pituitary macroadenoma and diaphragma sellae meningioma: differential diagnosis on MRI

Diaphragma sellae meningiomas are unusual tumours often not distinguished from pituitary macroadenomas. Preoperative differentiation is essential, because the trans-sphenoidal approach is used for surgical removal of adenomas, while meningiomas are approached via a craniotomy. We reviewed five patients in whom a diaphragma sellae meningioma was initially diagnosed as a nonsecreting pituitary macroadenoma. MRI criteria for differential diagnosis are discussed. The main findings considered are visibility of the pituitary gland, contrast enhancement, the centre of the lesion and sellar enlargement. These criteria, applied to a blind review, allow correct identification of the tumours. Received: 10 September 1997 Accepted: 22 April 1998     

Meningeal Gd-DTPA enhancement in patients with malignancies

Nineteen patients with malignant diseases and pathologically enhancing meninges were studied by pre- and postcontrast (Gd-diethylene-triamine pentaacetic acid) magnetic resonance (MR) scans. Two patterns of enhancement were recognized: the dural (14 patients) and the leptomeningeal (mainly pial) (5 patients). Positive cytology was found in only 3 of the 14 patients with dural enhancement (21%), whereas in the remaining 11 patients we noted either nonspecific CSF findings such as elevated protein, high white blood cell count, and low glucose or entirely normal CSF. Four patients (80%) in the group with leptomeningeal enhancement showed positive cytology and one had normal CSF analysis. We conclude that meningeal enhancement as seen on MR imaging is a nonspecific finding and correlates well with positive cytology only when the more rare form of leptomeningeal enhancement is encountered.     

The value of paramagnetic contrast agent gadolinium-DTPA in the diagnosis of pituitary adenomas

Summary The purpose of this study was to assess the role of MR imaging and the paramagnetic contrast agent Gadolinium-DTPA(Gd-DTPA) in the diagnosis of pituitary macroadenomas. 44 macroadenomas were examined with MRI before and after intravenous application of Gd-DTPA. Gd-DTPA produced excellent enhancement of solid adenoma. The best contrast between adenoma and surrounding structures could be gained on post-Gd T1-weighted images. Post-Gd images were equivalent to pre-Gd images in the evaluation of supra-and infrasellar extensions of macroadenomas. Post-Gd images had advantages in the evaluation of cavernous sinus invasion by adenoma. The difference in degree of contrast enhancement between adenoma and cavernous sinus facilitated the exact evaluation of lateral extension by adenoma in 18 cases. Almost equal degree of enhancement of both structures impaired tumor-sinus contrast in 2 cases. In the other 24 cases the tumor filled the cavernous sinus completely. It is our opinion that Gd-DTPA can be used on a widespread basis because of its excellent capability to highlight and delineate pituitary adenomas.     

低颅压综合征的MRI诊断

目的 分析低颅压综合征的MRI表现,以提高对本病的认识. 资料与方法 搜集经临床证实的低颅压综合征10例,治疗前均行MRI检查,其中3例仅行平扫,7例同时平扫和增强,3例加MRA,1例加MRV. 结果 10例均有硬脑膜增厚、静脉窦和脑静脉扩张;6例可见脑下垂和脑室缩小表现;4例可见侧枝静脉窦显影(基底丛和岩下窦);5例可见垂体增大;4例出现硬膜下积液;增强7例均见硬脑膜均匀性增厚强化,软脑膜无强化,2例见脊膜强化. 结论 低颅压综合征具有特征性的MRI表现,结合脑脊液压力检测,可以明确诊断.     

Dural tail sign in spinal meningiomas

ObjectiveTo study the association between the “dural tail sign” and spinal meningiomas on MR imaging.MethodsRetrospective review of MR examinations of all pathologically proven spinal meningiomas from 1998 to 2005 was performed. Lesions were evaluated for size, signal intensity, enhancement pattern, and presence or absence of dural tail. The dural tail length and direction in reference to the meningioma were also evaluated.ResultsSeven spinal meningiomas were identified in seven patients. One lesion was purely extradural, while the remaining were intradural extramedullary. Dural tail was present in four cases (57%) and its length ranged between 5 and 21 mm. The tail was seen cranial and caudal to the meningioma in three cases and only cranially in one. Coronal images were available in three cases and in two of these; the dural tail was clearly depicted.Conclusions“Dural tail sign” is as common in spinal meningiomas as in cranial meningiomas.