Dynamic CT of the laterosellar extradural venous spaces

We evaluated the ability of dynamic CT scanning to accurately demonstrate the laterosellar extradural venous spaces. Careful examination of 680 consecutive patients with this technique has permitted us to describe four main venous groups: the veins of the lateral wall (present in 98% of cases), the vein of the inferolateral group located beneath cranial nerve VI (present in 92% of cases), the medial vein located between the internal carotid artery and the pituitary gland (present in 20-30% of cases), and the vein of the carotid sulcus located between the intracavernous internal carotid artery and the lateral wall of the sphenoid bone (present in 65% of cases). The vein of the carotid sulcus is absent only when the internal carotid artery lies close to the sphenoid bone. In 12 patients with suspected cavernous sinus invasion, dynamic CT scanning demonstrated obliteration of the vein of the carotid sulcus. In five patients with huge tumors of the temporal region, dynamic CT scanning of the cavernous sinus permitted demonstration of normal laterosellar extradural venous spaces, thus permitting exclusion of intracavernous sinus invasion. We believe dynamic CT is the imaging technique best suited for studying the laterosellar extradural venous spaces. Its spatial resolution and dynamic capacity make it superior to MR, and it should be the first procedure when invasion of the cavernous sinus by a pituitary tumor is suspected.     

Magnetic resonance imaging of the cavernous sinus

The magnetic resonance (MR) appearance of the cavernous sinus was studied by correlating the MR images of normal volunteers and cryomicrotomic sections from six cadavers. In addition, MR images of patients with parasellar masses were compared with corresponding intravenously enhanced computed tomographic (CT) scans. The MR appearance of the cranial nerves in the cavernous sinuses is demonstrated, as well as MR signs of a parasellar mass, including obliteration of intracavernous venous spaces, displacement of the intracavernous internal carotid artery, and bulging of the lateral wall of the cavernous sinus. MR proved to be more effective than CT in delineating the parts of the cavernous sinus.     

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.     

侵袭性垂体腺瘤的MRI表现与MMP-9表达的相关性

目的研究侵袭性垂体腺瘤侵袭鞍底、鞍旁的不同MRI表现与MMP-9表达水平的相关性。资料与方法经手术、病理证实的垂体腺瘤90例,免疫组织化学染色,评价MMP-9的表达水平与肿瘤对鞍底及鞍旁的不同侵犯程度的MRI表现之间的关系。结果手术证实侵袭性垂体腺瘤59例。蝶窦腔内见肿瘤者30例（58.8%）,对诊断肿瘤侵袭性的敏感性为59%,特异性为100%,阳性预测值为100%,阴性预测值为65%。受侵犯的海绵窦中有95%（57/60）超过该侧颈内动脉外侧壁连线,对诊断肿瘤侵袭性的敏感性为95%,特异性为100%,阳性预测值为100%,阴性预测值为98%。垂体腺瘤包绕范围〉2/3者37侧,对诊断相应侧别海绵窦受侵袭的敏感性为62%,特异性为100%,阳性预测值100%,阴性预测值84%。侵犯海绵窦或鞍底的垂体腺瘤的MMP-9表达水平均高于未侵犯海绵窦或鞍底的垂体腺瘤。结论将鞍底破坏,窦腔内直接可见肿瘤组织作为鞍底受侵袭的MRI标准,将肿瘤向两侧超过颈内动脉海绵窦段和床突段外侧壁连线,或肿瘤包绕颈内动脉范围〉2/3至完全包绕作为海绵窦受侵袭的MRI标准。     

Cavernous sinus invasion by pituitary adenoma: MR imaging

PURPOSE: To define magnetic resonance (MR) imaging criteria for the diagnosis of cavernous sinus invasion by pituitary adenoma. MATERIALS AND METHODS: The MR images obtained in 106 patients (86 female, 20 male; age range, 16-71 years) were reviewed retrospectively by two physicians. The standard-of-reference criteria for invasion were the surgical findings. A chi(2) analysis was performed, and the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for nine groups of MR imaging signs were computed. RESULTS: Invasion of the cavernous sinus was certain (PPV, 100%) if the percentage of encasement of the internal carotid artery (ICA) by tumor was 67% or greater. It was highly probable if the carotid sulcus venous compartment was not depicted (PPV, 95%) or the line joining the lateral wall of the intracavernous and supracavernous ICAs was passed by the tumor (PPV, 85%). It was definitely not invaded (NPV, 100%) if the percentage of encasement of the intracavernous ICA was lower than 25% or the line joining the medial wall of the intracavernous and supracavernous ICAs was not passed by the tumor. CONCLUSION: The radiologic diagnosis of cavernous sinus invasion by pituitary adenoma remains difficult, but the above-mentioned criteria may be of assistance.     

MRI of growth hormone-secreting pituitary adenomas: factors determining pretreatment hormone levels

Preoperative serum growth hormone (GH) level is one of the most important determinants of outcome. Our aim was to assess MRI findings which may correlate with pretreatment GH levels in GH-secreting adenomas. We retrospectively studied 29 patients with acromegaly caused by a pituitary adenoma. Tumor size (height, width, thickness and volume), suprasellar extension, sphenoid or cavernous sinus invasion, signal intensity and contrast enhancement were studied. Linear regression analysis or Fisher's exact probability test was used for statistical analysis. Factors related to high GH levels were the maximum dimension of the tumour (r = 0.496, P < 0.01), its volume (r = 0.439, P < 0.05), spenoid sinus invasion (P < 0.01) and intracavernous carotid artery (encasement (P < 0.01). The other items were not related to serum GH levels. Since we believe surgery is the first choice of treatment and the cavernous sinus is difficult of access with a conventional surgical approach, preoperative assessment of invasion into the cavernous sinus is critical for predicting the surgical outcome. Low GH levels (5–50 ng/ml) were found with tumours medial to the intercarotid line and high levels (more than 101 ng/ml) with invasive tumours with carotid artery encasement. Variable GH levels were noted with tumours extending beyond the intercarotid line. Because functioning adenomas invading the cavernous sinus tend to have markedly high hormone levels, and only patients with carotid artery encasement showed markedly elevated GH levels, we believe carotid artery encasement a reliable MRI indicator of cavernous sinus invasion. Received: 1 January 1998 Accepted: 18 March 1999     

海绵窦侵袭型垂体瘤磁共振诊断系统及其相关因素分析

目的：探讨MR对海绵窦侵袭型垂体瘤的诊断价值，寻求建立一套海绵窦侵袭型垂体瘤的MR诊断系统。方法：选取手术中已经确诊的39例海绵窦侵袭型垂体瘤，同期162例非侵袭型垂体瘤做对照，应用计算机分析冠状位MR上肿瘤与海绵窦的关系。包括海绵窦形态的改变、窦内间隙的改变以及肿瘤与颈内动脉海绵窦段的关系等。将相关的各个类型均做为拟诊标准分别计算各自的灵敏度(Se)、特异度(Sp)、阳性预告值(PV )、阴性预告值(PV-)。依据医学统计学原理中的判别分析法进一步系统分析MR图像对于是否海绵窦侵袭型垂体瘤的诊断意义。结果：肿瘤包绕颈内动脉≥70％确诊侵袭的意义最大(PV ，100％)，肿瘤超过颈内动脉外侧连线的诊断意义也较高(PV ，86．1％)；如果肿瘤包绕颈内动脉的角度不到20％、肿瘤未超过颈内动脉内侧连线以及海绵窦内侧间隙未出现肿瘤则可以排除海绵窦侵袭的存在。同时应用判别分析法建立了一个海绵窦侵袭型垂体瘤及非海绵窦侵袭型垂体瘤的统计学判别计量数值表。从而完善了海绵窦侵袭型垂体瘤MR图像诊断系统。结论：通过系统分析垂体瘤加RI的表现，能够比较准确的确立海绵窦侵袭型垂体瘤的诊断。     

The relationship between MRI invasive features and expression of EMMPRIN, galectin-3, and microvessel density in pituitary adenoma

This study aimed to investigate the relationship between the expression of the molecular markers, extracellular matrix metalloproteinase inducer (EMMPRIN), galectin-3, and microvessel density (MVD) with MRI invasive features in invasive and noninvasive pituitary adenomas. MRI was performed preoperatively in 34 patients with histologically verified pituitary adenomas. The expression of EMMPRIN, galectin-3, and MVD was determined by using immunohistochemical techniques on excised surgical specimen from all patients. Correlative analyses between invasive MRI features and expression of EMMPRIN, galectin-3, and MVD were determined between invasive and noninvasive pituitary adenomas. Among MRI invasive features, adenoma crossing the lateral line (LL) of the internal carotid artery (ICA), percentage of intracavernous ICA encasement by the tumor over 50%, sphenoidal sinus invasion, irregular tumor shape, and bilateral ICA asymmetry correlated with increased expression of EMMPRIN and galectin-3 (P<.05), but tumor cystic necrosis and tumor apoplexy did not correlate with EMMPRIN and galectin-3 expression (P>.05). The invasive MRI features did not correlate with MVD expression. This study demonstrated that EMMPRIN and galectin-3 were associated with aggressiveness and invasion by pituitary adenoma. Furthermore, EMMPRIN and galectin-3 were two potential molecular markers for assessing the invasive potential of pituitary adenoma and may provide useful targets for molecular therapeutic strategy against invasive pituitary adenomas.     

Dynamic CT scanning for the evaluation of pituitary tumor invasion to the cavernous sinus

A CT method for evaluating cavernous sinus invasion by pituitary adenomas or parasellar tumors is described. This technique is easily performed without special software. A persistent, isolated visualization of the internal carotid artery seems to indicate invasion of the cavernous sinus.     

Comparison of MR imaging, CT, and angiography in the evaluation of the enlarged cavernous sinus

Twenty-one patients with enlargement of the cavernous sinus were studied with CT and MR imaging. Eighteen of the patients also had cerebral angiography. MR was superior to CT in differentiating parasellar aneurysms from neoplastic masses. MR was also superior to both CT and angiography in defining the relationships of cavernous sinus neoplasms to the internal carotid artery, pituitary gland, optic chiasm, infundibulum, and fifth cranial nerves. Only in the definition of bone erosion or hyperostosis was MR inferior to another method (CT). We conclude that MR should be the initial diagnostic study in patients with symptoms of a parasellar mass, with supplementation when necessary by CT and angiography.     

Occlusion of arteriovenous malformations of the cavernous sinus via the superior ophthalmic vein

The treatment of five patients with dural arteriovenous malformations (AVMs) of the cavernous sinus via the superior ophthalmic vein (SOV) is reported. The procedure was performed by transcutaneous puncture of the SOV under the guidance of real-time digital subtraction angiography. Complete resolution of the ocular symptoms was achieved in all cases. Angiograms after embolization showed complete obliteration of the malformation in four cases and partial obliteration in one. This method can cure dural AVMs of the cavernous sinus, with preservation of blood flow in the internal carotid artery. It is particularly indicated when the SOV is enlarged and when (1) dural AVMs of the cavernous sinus are fed by small branches of the internal carotid artery or direct carotid cavernous fistulas with small tears; (2) dural AVMs of the cavernous sinus are fed by multiple branches from both the internal and external carotid arteries, one or both sides; or (3) dural AVMs of the cavernous sinus or direct carotid cavernous fistulas recur after trapping of the internal carotid artery. Transcutaneous puncture and catheterization of the SOV was performed safely with the aid of digital subtraction angiography. The SOV approach was able to treat the fistula with preservation of the internal carotid artery.     

Tumor invasion of the anterior skull base: a comparison of MR and CT studies

Seven patients who had tumors arising in the anterior face or paranasal sinuses and invasion of the anterior skull base were evaluated with magnetic resonance (MR) and high resolution CT. Magnetic resonance was superior in evaluating tumor encasement of the carotid artery and invasion of the cavernous sinus; for assessing the relationship of the tumor to the anterior brain, optic nerves, and optic chiasm; in providing coronal images free from dental artifact; and in determining tumor extent within the infratemporal fossa. Bone destruction was more easily observed on CT than MR.     

Computed tomography of cavernous sinus diseases

Summary We retrospectively analyzed CT scans of 21 cavernous sinus lesions in an attempt to discover CT findings helpful to the differential diagnosis. With the integration of various CT observations it was possible to categorize the lesions into inflammatory, vascular, benign neoplastic and malignant metastatic lesions with few exceptions. Four of 5 cases of septic cavernous sinus thrombophlebitis revealed unilateral or bilateral multiple irregular filling defects in the enhancing cavernous sinus with or without orbital inflammatory change. Four of 5 cases of carotid-cavernous fistula demonstrated unilateral or bilateral diffuse bulging and homogeneous enhancement of the cavernous sinus with obliteration of normal low densities of cranial nerves and gasserian ganglion. Dilatation and tortuosity of superior ophthalmic vein were also associated. Four of 5 cases of benign neoplastic lesion showed well-circumscribed enhancing masses confined to the cavernous sinus with pressure erosion or hyperostosis of adjacent bone. Five of 6 cases of malignant metastatic lesion showed changes suggesting malignancy such as destruction of adjacent bone or associated manifestations of intracranial spread. As compared with the axial scan, coronal scans proved to be more sensitive in detection of subtle cavernous sinus expansion, and superior in evaluation of intracavernous neural structures, relationships with the pituitary gland and changes in the skull base. Axial scans, however, were superior in detection of associated orbital and intracranial abnormalities. Scans in both projections are needed in the evaluation of most cavernous sinus diseases.     

Symptomatic cavernous sinus aneurysms: management and outcome after carotid occlusion and selective cerebral revascularization

BACKGROUND AND PURPOSE: Therapeutic internal carotid artery (ICA) occlusion for symptomatic intracavernous artery aneurysms can result in ischemic infarction despite normal clinical balloon test occlusion (BTO). We evaluated outcomes in patients with symptomatic cavernous sinus aneurysms in whom clinical BTO was normal, who underwent carotid occlusion with selective bypass surgery guided by physiologic BTO using quantitative cerebral blood flow (CBF) analysis by means of stable xenon-enhanced CT. METHODS: After a normal clinical BTO, 26 consecutive patients with symptomatic cavernous sinus aneurysms underwent a baseline xenon-enhanced CT CBF analysis followed by a second CBF analysis, during which repeat BTO was performed. Patients with a decrease in cortical CBF to below 30 mL/100 g/min were considered moderate risk and those with greater than 30 mL/100 g/min were low risk for developing postocclusion ischemic infarction. Moderate-risk patients underwent cerebral revascularization followed by proximal carotid occlusion. Low-risk patients underwent carotid occlusion alone. Patients were clinically followed up for at least 3 months after carotid occlusion. All patients underwent head CT at least 1 month after carotid occlusion. RESULTS: Eight patients were moderate risk and 18 low risk. Mean follow-up was 15.3 months. Mean CT follow-up was 10.2 months. No low-risk patient developed a postocclusion ischemic deficit by examination or infarct by CT. One patient in the moderate-risk group developed right hemiparesis and a left posterior middle cerebral artery infarction by CT 2 months after carotid occlusion. CONCLUSION: In this series, BTO combined with quantitative CBF analysis was a safe and reliable technique for identification of patients at risk for ischemic infarction after carotid occlusion, despite a normal clinical BTO.     

A comparison of CT and MRI in the assessment of the pituitary and parasellar region

We have carried out a prospective study to compare high resolution thin slice, contrast-enhanced, axial computed tomography (CT) with unenhanced magnetic resonance imaging (MRI) at 1.5T in the assessment of the pituitary and parasellar region. Forty patients with suspected pituitary disease presenting to an endocrine unit were studied. MRI was superior to CT for the identification of the posterior pituitary and pituitary stalk and was better at showing the cystic nature of tumours. Visualization of the optic chiasm and assessment of displacement of the optic chiasm and the carotid arteries were also better with MRI. CT was equally good at showing cavernous sinus displacement or invasion, sphenoid sinus invasion and erosion of the floor of the sella turcica and was the only technique able to show calcification of the gland. More focal abnormalities were seen in the pituitary gland with CT than with unenhanced MRI, but there was a higher false positive rate for microadenoma detection with CT. All the scans were interpreted separately by three observers, two radiologists and one clinician. The percentage agreement between the observers for the identification of pituitary and parasellar structures was better for MRI than for CT and the clinician in particular found interpretation of the MR images easier. MRI thus not only gives more information overall than CT but it is a more reliable technique between different observers for the assessment of the pituitary and parasellar region.     

Internal carotid artery occlusion due to idiopathic cranial pachymeningitis.

A 35-year-old black woman had a 6-month history of headaches and a 1-month history of abducens nerve palsy. MR showed a mass in the sella and cavernous sinuses with encasement of the carotid artery. The mass enhanced intensely and homogeneously with Gd-DTPA. Arteriography revealed complete occlusion of the left internal carotid artery and severe stenosis of the C5 and C6 segments of the right internal carotid artery. Transsphenoidal biopsy of the mass led to the diagnosis of idiopathic cranial pachymeningitis.     

Magnetic resonance imaging of the cavernous sinus

The magnetic resonance (MR) appearance of the cavernous sinus (CS) was studied in 10 normal and 23 abnormal CSs(11 vascular and 12 neoplastic lesions) using T1-weighted spin echo images with and without Gd-DTPA. In normal CSs, the intracavernous carotid artery (ICA) was disclosed as an area of signal void that was not enhanced with Gd-DTPA. Most venous flow showed low intensity and was markedly enhanced with Gd-DTPA. Venous flow, however, was heterogeneous, which suggested the distribution of flow velocities. In the carotid-cavernous sinus fistulas (CCFs), the ICA and shunted flow were disclosed as areas of signal void and their relationship was clearly shown. Normal venous flow appeared as a low intensity area even with CCFs. In the cavernous aneurysms, thrombosis and patent arterial flow were shown, but in one case it was impossible to differentiate patent arterial flow from calcification. In neoplastic lesions, CS invasion was suspected by encasement or marked dislocation of the ICA, disappearance of venous flow, and extension of extrasellar tumors to the medial wall and extension of sellar tumors to the lateral wall. MR was found to be a promising diagnostic modality for the evaluation of the CS.     

外伤性颈动脉海绵窦瘘的综合影像评价

目的 评价各种影像学检查手段在诊断外伤性颈内动脉海绵窦瘘中的作用。资料与方法 回顾性分析15例颈动脉海绵窦瘘患者的各种影像学表现，其中CT、超声检查15例，脑血管造影12例，MRI检查3例。结果 颈内动脉海绵窦瘘CT表现为：眼球突出，眼上静脉扩张和海绵窦增大(15／15)，眶内软组织肿胀(9／15)和眼外肌肥厚(10／15)。MRI表现与CT大致相同，MRA可立体显示扩张的眼上静脉和瘘口(2／3)。脑血管造影于动脉期可见患侧海绵窦扩大显影并眼上静脉逆向充盈显影(12／12)，并可见瘘口显示(11／12)，压迫患侧颈总动脉，健侧颈内动脉造影可见患侧颈内动脉和海绵窦显影(9／12)。经颅多普勒超声检查可显示眼上静脉和海绵窦区的异常血流信号(15／15)，并能准确评价颈内动脉各段血流动力学改变。结论 各种影像学检查手段都有其优势和局限性，各种手段综合应用才能满足临床需要。     

Endovascular treatment of high-flow carotid cavernous fistulas by stent-assisted coil placement

BACKGROUND AND PURPOSE: Endovascular techniques are the methods of choice for the treatment of patients with carotid cavernous fistulas. We report our experience using stent-assisted coil placement for treatment of patients with high-flow fistulas that are associated with severe laceration of the internal carotid artery. METHODS: In a retrospective review of an internal endovascular therapy database covering the interval between October 2001 and October 2003, we identified a total of 5 patients presenting with 6 high-flow type A carotid cavernous fistulas (one had a bilateral fistula) that were associated with severe laceration of the internal carotid artery. All were treated first with stenting of the injured segment of the internal carotid artery followed by transarterial (3/6) and/or transvenous (4/6) obliteration of the fistula with detachable platinum coils. In 2 cases, a liquid adhesive was also used. In all instances, a compliant balloon was inflated within the stented arterial segment during coil deposition to avoid extension of coils into the parent artery. RESULTS: All 6 fistulas were obliterated, and each internal carotid artery was successfully reconstructed. Except for posttraumatic cranial nerve dysfunction in 1 patient, clinical outcome was very good. Follow-up angiograms in 3 of the 6 patients obtained at intervals between 3 and 6 months (mean, 4.5 months) revealed no fistula recurrence and no evidence of intimal hyperplasia within the stent. CONCLUSION: In this series of patients with high-flow carotid cavernous fistula associated with severe injury to the internal carotid artery, stent-assisted coil placement offered a safe and effective treatment. Stent-assisted coil placement may increase the ability to successfully treat fistulas with severe injury to the internal carotid artery with preservation of the parent artery.     

Comparison of MR imaging and CT in pituitary macroadenomas

The findings on mid-field MR imaging and CT were compared retrospectively in 65 patients with pituitary macroadenomas. The evaluation comprised tumour extension and delineation, invasiveness, relationship to adjacent structures, and internal tumoral changes. MR was superior to CT except in the demonstration of bone changes and tumour calcification. The superiority of MR was most pronounced regarding cavernous sinus invasion, tumour relationship to the carotid arteries and optic chiasm, and tumour haemorrhage. Extensive bone changes were visualized with both methods; erosions were often seen only with CT. It is concluded that MR is the preferable method for evaluation of pituitary macroadenomas. CT is useful as a supplementary modality when detailed information on bone anatomy is required, particularly if a transsphenoidal surgical approach is contemplated.