MRI of pituitary adenomas in acromegaly

Adenomas causing acromegaly represent at least a quarter of pituitary adenomas. We studied 12 patients presenting with active acromegaly due to a pituitary adenoma with a 1.5 T superconductive MRI unit. All had T1-weighted sagittal and coronal sections before and after Gd-DTPA; six had coronal T2-weighted images. Surgical correlation was obtained in seven patients. Histologically, there were eight growth hormone (GH)-secreting and three mixed [GH and prolactin (PRL) secreting] adenomas, and one secreting GH, PRL and follicle-stimulating hormone. Macroadenomas (10) were more frequent than microadenomas (2). No correlation was found between serum GH and tumour size. There were nine adenomas in the lateral part of the pituitary gland; seven showed lateral or infrasellar invasion. Homogeneous, isointense signal on T1- and T2-weighted images was observed in six cases. Heterogeneous adenomas had cystic or necrotic components. Received: 29 April 1996 Accepted: 8 August 1996     

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.     

Imaging of giant pituitary adenomas

We present five proven giant pituitary adenomas studied by CT and MRI, and review the clinical and imaging findings. Our aim was to examine the radiologic appearances and to search for criteria useful in distinguishing these tumors from other sellar and suprasellar tumours, mainly craniopharyngioma. The main differences from small adenomas were high prevalence of macrocysts, a more invasive behaviour and a clinical picture dominated by mass effect rather than endocrine disturbance. Factors supporting the diagnosis of pituitary adenoma in a giant intra- and suprasellar mass include: infrasellar extension, absence of calcification and presence of low-signal cysts on T1-weighted images. Received: 13 October 1997 Accepted: 25 February 1998     

MRI of pituitary adenoma with extensive amyloid formation

We report a patient with a pituitary adenoma with extensive amyloid formation. T2-weighted MRI was most characteristic for amyloid deposition. Received: 30 July 1998 Accepted: 20 October 1998     

Metastases from a pituitary adenoma: MRI

Few cases of pituitary adenoma with metastases have been reported. We report a case with histologically benign intracranial and cauda equina metastases. We compare it to the others in the literature. Received: 30 March 1998 Accepted: 22 January 1999     

MRI of pituitary macroadenomas with reference to hormonal activity

Summary In 115 patients with pituitary macroadenomas, the findings on mid-field MRI were correlated with the hormonal activity of the tumours. Adenomas secreting growth hormone (GH), prolactin (PRL) and clinically nonsecretory adenomas were studied. Tumour size, invasiveness and signal intensity patterns were recorded. Relaxation times and ratios of signal intensity and proton density (relative to the corpus callosum) were analysed in areas of apparently solid tissue in a subgroup of 59 previously untreated patients. Invasiveness was more common in PRL-and GH-secreting adenomas than in the nonsecreting ones. Diffuse invasion of the base of the skull was most common in prolactinomas, and associated with a lower frequency of suprasellar tumour extension. In prolactinomas, a correlation was found between the maximum serum PRL level and tumour size. Haemorrhagic, cystic or necrotic areas were less common in GH-secreting tumours than in the other types. Haemorrhage was more common in prolactinomas than in nonsecreting tumours. MR parameters were similar in prolactinomas and nonsecreting adenomas, but indicated a smaller amount of water in GH-secreting tumours.     

多参数MRI对垂体腺瘤评估的研究进展

垂体腺瘤是最常见的鞍区肿瘤,其质地、血供及侵袭性等生物学特征是影响手术切除的重要因素。精准、全面的术前评估对于肿瘤的治疗具有重要意义。影像检查是重要的辅助检查手段,对肿瘤的精准治疗起着重要作用。MR多种新型成像序列的应用不仅可以提供详细的解剖学信息,还能进一步提供肿瘤质地、微血流灌注特征及对视路损害程度等信息,从而提高手术安全性及临床治愈率,降低肿瘤手术并发症发生率及复发风险。就近年来垂体腺瘤相关多参数MRI技术发展及其对腺瘤生物学特征的临床评估价值予以综述。     

MRI visualization of complete bilateral optic nerve involvement by pituitary adenoma: a case report

With large pituitary adenomas, the optic nerves and chiasm usually lie on the tumour capsule and are displaced superiorly. We report a large invasive pituitary adenoma, with complete involvement of both optic nerves. Review of the preoperative MR images demonstrated the optic nerves, with signal intensity close to that of cerebral white matter, and different from the flow void of the basal cerebral arteries. Correlation of this observation with intraoperative findings is discussed.     

Thymic hyperplasia due to excess growth hormone stimulation: A case report

Growth hormone has a strong role in stimulation of the thymus. We report a case of thymic hyperplasia due to excess endogenous growth hormone in the setting of acromegaly. Acromegaly often presents with systemic manifestations that may be confused with a systemic hematologic malignancy or infection, especially if an anterior mediastinal mass is present but unrecognized as a benign thymic hyperplasia. It is important for radiologists to be aware of this association between growth hormone and thymic stimulation because it may increase confidence diagnosing thymic hyperplasia in this setting, and avoid unnecessary mediastinal biopsy or surgery.     

垂体微腺瘤MRI诊断(附25例分析)

目的：探讨和总结25例垂体微腺瘤的磁共振成像（MRI）表现。方法：对25例经MRI平扫：冠状位于SE序列T2加权成像（T2WI）、FFE序列T1加权成像（T1WI）,及行Gd-DTPA增强扫描：冠状位下FFE序列T1WI、矢状位下FFE序列T1WI检查,经手术切除得到病理证实的病例进行分析,其中7例行动态增强和延迟扫描。结果：25例垂体微腺瘤均位于垂体前叶,单发19例,其中14例位于垂体右侧部,多发6例。MRI平扫24例（T1WI）为低或稍低信号、1例为高或稍高信号;23例（T2WI）为高或稍高信号,但2例为等或稍低信号,增强后即刻扫描25例均为低或稍低信号,7例动态增强扫描延迟25－30min后1例有明显强化。结论：垂体微腺瘤MRI表现有一定特征性,MRI对诊断垂体微腺瘤有较大价值。     

A clinical and histopathological study of factors affecting MRI signal intensities of pituitary adenomas

Our aim was to elucidate the factors which determine the MRI signal intensities of pituitary adenomas. We examined 51 patients with surgically-confirmed pituitary adenomas. Using a spin-echo pulse sequence (SE 500/15), coronal and sagittal images (3 mm slices) were obtained. Signal intensities on T1-weighted images were measured in the parenchyma of the adenoma and in normal grey matter. The relative intensity of the adenoma was assessed by calculating the ratio of its signal intensity to that of the normal grey matter of the same patient. Parafin-embedded sections were used for haematoxylin and eosin staining. The number of cells in a prescribed area was counted, and the mean of five such counts was taken as the cell density. Immunohistochemically stained sections using antibodies for various pituitary hormones were similarly examined; the ratio of the total number of hormone-positive cells to the overall total number of adenoma cells was calculated. Four independent variables were used in the analysis: the age of the patient, the maximum diameter of the adenoma, the cell density and the proportion of hormone-positive cells in the adenoma and, with the signal intensity ratio as the dependent variable, a multiple regression analysis was performed. This revealed that the the greatest influence upon the signal intensities on T1-weighted images was the proportion of hormone positive cells.     

MRI of a pituitary cryptococcoma simulating an adenoma

We describe a rare pituitary cryptococcoma in an immunocompetent patient, with radiological features similar to those of a pituitary macroadenoma. Although unusual, it should be added to the list of differential diagnosis of pituitary masses. Contrast enhancement of adjacent meninges differentiated the lesion from an adenoma.     

垂体腺瘤侵袭海绵窦时颈内动脉的MRI表现

目的　研究垂体腺瘤对颈内动脉海绵窦段的影响以及垂体腺瘤侵袭海绵窦时颈内动脉的MRI表现。资料与方法　回顾分析 10 3例经病理证实的垂体腺瘤的MRI资料 ,测量两侧颈内动脉距中线距离、横径、被肿瘤包绕程度、颈内动脉间距 ,并与 15 0例非鞍区病变患者颈内动脉的MRI表现相比较。结果　非鞍区病变患者两侧颈内动脉海绵窦段间平均距离为 (17.0± 3.5 )mm ,而垂体腺瘤患者则为 (2 4 .4± 4 .2 )mm。颈内动脉间距与肿瘤横径明显相关 ,而与肿瘤体积的相关性相对不明显。海绵窦是否受侵犯与同侧颈内动脉被包绕范围明显相关 ,而与颈内动脉距中线距离及颈内动脉横径无关。结论　两侧颈内动脉间距仅能反映垂体腺瘤的大小 ,与侵袭性无关。海绵窦是否受侵与颈内动脉的移位、狭窄情况无关 ,而与颈内动脉的包绕程度相关 ,颈内动脉被肿瘤包绕范围 <1/ 3,海绵窦未受侵犯 ;若 >2 / 3,则海绵窦受侵犯。颈内动脉的包绕程度可作为评价垂体腺瘤是否侵袭海绵窦的指标     

Postoperative follow-up of pituitary adenomas after trans-sphenoidal resection: MRI and clinical correlation

Our purpose was to correlate the morphological changes seen on MRI studies of the sellar region after trans-sphenoidal resection of pituitary adenomas with clinical and hormonal studies. Between January 1993 and March 1994, 16 patients with a pituitary adenoma (9 macroadenomas and 7 microadenomas) were subjected to trans-sphenoidal resection and included in a prospective study. The protocol consisted of MRI, hormonal and visual studies at the following times: immediately postoperative (1st week), 1st month, 4th month and 1st year after surgery. The evolution of the contents of the sella turcica (tumour remnant, packing material and gland tissue), effects on the infundibulum, optic chiasm, cavernous sinus and sphenoid sinus were correlated with the clinical and hormonal studies. Stabilisation of the postsurgical changes occurred by the 4th month. Tumour remnants were noted in the immediate postoperative period in macroadenomas. Compression of the infundibulum was the only reliable indicator of possible involvement. Optic chiasm compression, defined as close contact between the chiasm and the tumour, was the only morphological finding that indicated visual impairment. There was no standard repneumatisation pattern in the sphenoid sinus, since mucosal changes resembling sinusitis were one of the postsurgical changes. We found MRI not to be useful for follow-up of microadenomas. Received: 18 July 1995 Accepted: 15 November 1995     

侵袭性垂体腺瘤的MRI诊断价值

目的 研究侵袭性垂体腺瘤的MRI影像特征。方法 回顾分析32例经手术及病理证实的侵袭性垂体腺瘤的MRI表现。结果 侵袭性垂体腺瘤的MRI影像学表现:①肿瘤超过颈内动脉(ICA)外侧壁切线;②海绵窦外侧静脉丛间隙消失;③3个或3个以上海绵窦静脉丛间隙消失;④窦内颈内动脉(ICA)被包绕50%以上,甚至被完全包裹。结论 MRI以无创伤、无骨伪影、软组织分辨率高、解剖背景清楚及三维成像等优点,是术前诊断侵袭性垂体腺瘤最主要和最重要的检查手段。     

侵袭性垂体腺瘤:MRI与术中对照研究(附35例回顾分析)

目的:探讨MRI推断侵袭性垂体瘤质地、侵袭性的价值。方法:35例行MR检查侵袭性垂体瘤病人,测量T1WI及T2WI肿瘤信号与脑白质信号的比值和强化前后肿瘤T1WI信号强度比值,与其术中所见及术后病理对照,术中据肿瘤硬度分为质软、中等、硬;术后瘤体送检,结果进行统计学分析。结果:T2WI瘤体与白质信号比值与瘤体质地有明显相关性(P<0.01);MRI所示垂体瘤海绵窦及鞍周侵袭与术中及术后病理总符合率达85.3%。结论:MRI可以在术前准确预测侵袭性垂体瘤的质地、侵袭性。     

正常成人垂体的磁共振测量研究

目的:观察正常垂体形态、测量其大小并探讨其与年龄、性别的变化关系。方法:选取300例非鞍区病变及内分泌症状的正常成年人。按性别、年龄分为5组:20~29岁组,30~39岁组,40~49岁组,50~59岁组及60岁以上组,每组男女各30例,MRI测量矢状位腺体及后叶前后径、高径以及垂体柄前后径;冠状位腺体宽径、高径及垂体柄宽径;比较分析不同性别、年龄段上述各径线MR测量值的变化特点。结果:成人男、女正常垂体冠状高径分别为(4.01±1.08)mm、(3.99±1.37)mm,冠状宽径分别为(9.75±1.63)mm(、10.17±1.59)mm;矢状高径分别为(4.46±1.24)mm(、4.68±1.61)mm;前后径分别为(10.15±1.51)mm(、10.24±0.90)mm;垂体后叶矢状高径分别为(4.01±1.43)mm(、4.59±1.17)mm,前后径分别为(2.01±0.66)mm、(1.98±0.70)mm;垂体柄冠状宽径分别为(1.56±0.21)mm、(1.59±0.21)mm,前后径分别为(1.50±0.23)mm、(1.52±0.22)mm。垂体高径在20~29年龄组最大,有随年龄增大而逐渐减小趋势;垂体宽径及前后垂体后叶及垂体柄各径线有先增大后减小趋势。结论:成人垂体各径线随年龄的变化有先变大后减小趋势。各径线与年龄有一定统计学差异而与性别无明显统计学差异。     

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     

正常青少年垂体MRI研究

目的研究正常青少年垂体大小、形态变化及其与年龄、身高、体重的相关性。方法选取152例6．0—18．9岁正常青少年的垂体MRI资料，于SE序列T1WI头颅正中矢状及冠状面上观测垂体大小形态及信号特征。结果得到6-〈10岁、10～〈15岁、15．0—18．9岁3组正常垂体大小、形态及信号特征资料。在10-〈15岁、15．0～18．9岁组，男性隆凸型分别占47．6％（10／21）、52．0％（13／25），球形垂体分别占14．3％（13／21）、32．0％（8／25）；女性隆凸型分别占70．9％（22／31）、90．0％（18／20），球形垂体分别占45．2％（14／31）、60．0％（12／20）。青春发育期腺垂体与年龄呈正相关生长（r男=0．74，t=3．624，P=0．004；r女=0．94，t=9．562，P=0．000），与身高、体重无明显相关性（P〉0．05）。结论青春发育期垂体大小、形态变化大，随年龄增长，垂体明显增生肥大，垂体上缘也逐渐隆凸。球形垂体在青春发育期可为正常现象，在青春期女性中占有很大比率，易与垂体微腺瘤混淆，需结合临床及生化检查结果，避免误诊。     

Concomitant pituitary adenoma and Rathke's cleft cyst

We reviewed the clinical, radiological and surgical findings in patients with both pituitary adenoma and Rathke's cleft cyst. We retrospectively selected patients with both lesions from the 374 patients in whom a sellar/juxtasellar lesion was detected on MRI at 1.5 tesla. All patients received intravenous contrast medium. Concomitant pituitary adenoma and Rathke's cleft cyst were found in eight patients (2.1 %). The frequency of the combination was 3.5 % of pituitary adenomas and 11 % of Rathke's cleft cysts. Symptoms were always due to the adenoma, secreting adrenocorticotrophin in two patients and growth hormone in six. The adenoma was larger in five patients, and the cyst in three. The cysts gave variable signal. The adenoma was adjacent to the cyst in seven patients, and enclosed it in the other patient. As a result of experience with MRI, concomitant pituitary adenoma and Rathke's cleft cyst are now known not to be as rare as thought previously. When a nonenhancing cyst-like structure is demonstrated in a patient with pituitary adenoma, the possibility of a coexisting Rathke's cleft cyst should be considered. Received: 23 March 2000/Accepted: 12 July 2000