20031013
History: Patient being evaluated with head CT
病史：病人头CT检查
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磁共振检查
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Findings: On the CT, the images show an enlarged right vestibular aqueduct. On the MR, there is high signal in the right vestibular aqueduct that is enlarged similar to the CT. No other abnormalities are present.
Diagnosis: Vestibular Aqueduct Syndrome
影像学表现：CT图像显示右侧前庭导水管扩大。MR显示右侧前庭导水管扩大，类似CT，可见高信号。无其它异常。
诊断：大前庭导水管综合征
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Congenital hearing loss is a common problem that may be conductive or sensorineural in nature. In patients with conductive hearing loss, there is usually anomalies involving the malleus, incus, and stapes or their configuration. Sensorineural hearing loss is related to multiple possible inner ear deformities. These deformities can involve the internal auditory canal, cochlea, semicircular canals, vestibule, or vestibular aqueduct. Abnormalities of the vestibular aqueduct can range from wide dilatation to complete obliteration. The vestibular aqueduct syndrome occurs with dilation of the vestibular aqueduct to greater than 1.5 mm. Clinically, patients with a dilated vestibular aqueduct will most often have pure sensorineural hearing loss, but may also have mixed conductive and sensorineural findings. Less frequently, these patients present with vestibular symptoms. When hearing loss is present, the clinical course is variable with hearing loss that may or may not be progressive.
先天性失聪是常见疾病，可以是传导性，也可以是神经性。对于传导性耳聋病人，常常是锤骨、砧骨、蹬骨的畸形或者三者关系异常。神经性耳聋与多种可能的内耳畸形有关。畸形包括内耳道、耳蜗、半规管、前庭或者前庭导水管的异常。前庭导水管的异常包括扩大或者小事。大前庭导水管综合征发生于前庭导水管大于1.5mm时。临床上，前庭导水管扩张病人大多为纯神经性耳聋，部分病人也可以具有混合性耳聋。少见情况下，病人可以表现为前庭症状。当出现耳聋的时候，临床上游不同程度的耳聋，可以为进行性加重，也可以为非进行性加重。
The exact etiology of the vestibular aqueduct syndrome is not clear. However, in 60% of cases, there is an associated abnormality of the cochlea, vestibule, and/or semicircular canals suggesting an insult during different stages of development can lead to different associated abnormalities. When cochlea anomalies are present, they are of the Mondini type (incomplete partitioning of the cochlea with only an intact basilar turn). Embryologically, the cochlea partitioning and formation of the vestibular aqueduct occur simultaneously as the last developing structures in the inner ear. Thus, an insult at this time of development could involve both structures. There is no known hereditary association.
大前庭导水管综合征的确切病因不明。但是在60%的病例，有相关的耳蜗、前庭和/或半规管的异常，提示不同发育阶段出现的异常可以出现不同的异常。当具有耳蜗异常时，属于Mondini型（耳蜗的不完全性分离，只有完整的底部螺旋）。从组胚的角度讲，耳蜗的分离与前庭导水管的形成是同时的，属于内耳发育的最后阶段。因此这个时候发生的病变可以同时累及两者。尚没有发现遗传性特征。
Vestibular aqueduct dilation (>1.5 mm) is present in 1.5% of patients with hearing loss. Most frequently, the dilation is unilateral. As mentioned above, 60% will have other associated abnormalities in the inner ear. In the 40% with no additional radiographic abnormality, it is possible that abnormalities of the membranous labyrinth exist that are not detected.
1.5%的失聪病人具有前庭导水管的扩大（＞1.5mm）。通常是单侧的扩张。如上面所述，60%的病例具有伴随内耳的异常。40%的没有发现放射学异常的病人中，可能是未被发现的膜迷路的异常。
Radiologic Overview:
Plain Films: Not detectable.
Computed Tomography: CT is the imaging study of choice. Temporal bone CT demonstrates a widened vestibular aqueduct greater than 1.5 mm. Sagittal reformats can be helpful to see the vestibular aqueduct anatomy better. In addition, multiple other associated abnormalities of the inner ear may be present.
MR: T2 images through the temporal bone demonstrates high signal in the dilated vestibular aqueduct. Other abnormalities should be looked for, however, MR does not evaluate bone detail nearly as well as CT. MR can help rule out an acoustic schwannoma or other posterior fossa process.
影像学检查
平片：无诊断意义。
CT：CT是首选影像学检查手段。颞骨CT显示前庭导水管扩张，大于1.5mm。矢状重组图像有助于显示前庭导水管的结构。同时，可能同时存在多发的其它内耳异常。
MR：颞骨层面T2图像显示扩张的前庭导水管内高信号。也需要观察其它异常，但是显示骨骼病变方面CT更具优势。MR有助于排除听神经雪旺细胞瘤或者其它后颅窝病变。
Key Points:
Vestibular aqueduct syndrome is an often-overlooked cause of sensorineural hearing loss that is usually unilateral.
Diagnosis is usually made by CT of the temporal bones with a vestibular aqueduct that measures >1.5 mm.
In 60% of patients other abnormalities of the inner ear are present.
关键点：
1． 常为单侧的大前庭导水管综合征作为神经性耳聋的病因常常容易忽略
2． 根据颞骨CT可以做出诊断，前庭导水管大于1.5mm
3． 60%的病人存在其它内耳病变。
考试结束，回到济南，重新开工
History: Seventy-year-old man with dizziness and ataxia.
病史：70岁男性，头晕，运动失调
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磁共振图像
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Findings: Head CT: Predominantly cystic lesion in the cerebellum involving deep cerebellar hemisphere and extending to the vermis. It has a well defined periphery with a small, solid component superiorly, which is partly calcified. There is edema and partial effacement of the fourth ventricle, dorsal pons, and mid brain on the left. MRI shows a large cystic mass in the left cerebellar hemisphere with a solid, irregular component superiorly which enhances inhomogeneously.
影像学表现：头CT：小脑半球囊实性占位，囊性为主，累计小脑半球深部，延伸到小脑蚓部。边界清楚，上部层面具有小的实性部分，部分钙化。可见水肿和第四脑室的变窄，呗侧脑桥、中脑向左侧移位。MRI显示左侧小脑半球囊性肿块，可见上部不规则实性部分，不均匀强化。
病人胸部平片
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Differential Diagnosis:
• Hemangioblastoma
• Astrocytic tumor
• Metastatic disease
鉴别诊断：
血管母细胞六
星形细胞瘤
转移瘤
Discussion of Disease: Cystic infratentorial mass. Tumors in the posterior fossa are considered some of the most critical brain lesions. This is due primarily to the limited space within the posterior fossa, as well as the potential involvement of the vital brain stem nuclei. About 15-20% of brain tumors in adults occur in the posterior fossa. The top three differentials for this patient include hemangioblastoma, astrocytoma, and metastasis.
讨论：囊性幕下占位病变。后颅窝肿瘤是非常严重的病变。这是因为后颅窝空间有限，并且可以累及脑干的重要核团。成年人脑肿瘤的15~20%发生于后颅窝。需要鉴别的三大疾病包括血管母细胞瘤，星形细胞瘤和转移。
Cystic cerebellar astrocytoma comprises about 33% of all posterior fossa tumors in children. It represents 25% of all pediatric tumors. Average age of presentation is 9 years. Typically, cerebellar astrocytoma presents as a laterally located cyst with a well-defined solid component. It may be solid or cystic. It may be located medially in the vermis or laterally in the cerebellar hemisphere
囊性星形细胞瘤占儿童后颅窝肿瘤的33%。占儿童肿瘤的25%。平均发病年龄为9岁。小脑星形细胞瘤的典型表现为边界清楚的囊实性占位位于一侧。可以以实性为主，也可以以囊性为主。可以位于内测的小脑蚓部或者外侧的小脑半球。
Hemangioblastoma represents about 7-12% of all posterior fossa tumors. About 70% of hemangioblastomas occurring in the cerebellum are cystic. Age of presentation is 30-40 years old. Hemangioblastomas are more common in males. Hemangioblastoma may be associated with von Hippel-Lindau disease. Solid hemangioblastomas are more common in patients with Hippel-Lindau disease.
血管母细胞瘤占后颅窝肿瘤的7~12%。70%的为小脑半球的囊性病变。发病年龄为30~40岁。血管母更常见于男性。与VHL病可能有一定关系。VHL病病人更常见实性血管母细胞瘤。
Three percent and 18% of all cranial metastatic lesions occur in the brainstem and cerebellum, respectively. Primary sites include breast, lung, skin, and kidney. Solitary metastasis is better treated by surgical removal before radiation therapy. Surgery also should be considered in case of radiosensitive original tumors or when the primary source is unknown.
脑干和小脑半球的颅内转移瘤分别占到3%和18%。原发病灶包括乳腺、肺、皮肤、肾。实性转移瘤的较好的治疗方法为术后放疗。原发灶对放疗敏感或者原发病灶不明时，也应该进行手术。
Patients presenting with posterior fossa tumors undergo surgery for the following reasons:
• To decompress the posterior fossa for the purpose of relieving pressure on the brain stem and/or to release intracranial pressure and avert the risk of herniation
• To histopathologically diagnose the tumor
• To determine further plan of management depending on the nature of the tumor
• When indicated, to shunt CSF to the peritoneal cavity to treat obstructive hydrocephalus associated with the tumor
后颅窝肿瘤手术治疗的原因如下：
后颅窝减压，解除对脑干的压迫，或者缓解颅内压，逆转脑疝。
从组织病理学上诊断肿瘤。
根据肿瘤的本质制定治疗方案
如果存在适应症，建立腹膜腔脑积液分流，减轻肿瘤相关的阻塞性脑积水。
This patient had chest film with large peripheral mass. He underwent surgery for his brain mass and the pathology revealed metastatic disease of squamous cell carcinoma.
病人胸片显示大的周围型肿块。术后病理证实是鳞状细胞癌转移。
Radiologic Overview of the Diagnosis:
• Magnetic resonance imaging
o MRI appearance of cerebellar astrocytoma
Intra-axial, either midline or hemispheric, mass
Prominent cystic component that is hypointense in T1-weighted images and slightly hyperintense in T2-weighted images (more protein content)
Mural nodule, usually enhanced in T2 images
Displacement of effacement of the fourth ventricle
Hydrocephalic changes due to obstruction of the CSF pathway
Nodule that usually is enhanced with contrast
Cystic wall that may or may not enhance
Heterogenicity and calcification, rarely found
o MRI appearance of posterior fossa hemangioblastoma
Appears as a cystic mass with pial-based mural nodule that is slightly hyperintense and enhanced prominently with intravenous contrast
Appearing as regions of signal void on spin-echo images, abnormal vessels that may be found adjacent or within the tumor
Cyst that may be isointense or hyperintense on T1- and T2-weighted images
Cyst wall that often is sharply delimited
Variation of MRI appearance, including presence of hemorrhage in the cyst, solid rather than cystic mass, multiple lesions, and associated syrinx cavity
影像学诊断：
磁共振
小脑星形细胞瘤MR表现：
中线或者半球的轴内病变
囊性部分呈T1高信号，T2稍高信号（蛋白成分为主）
可见壁结节，常在T2图像上显示强化。
第四脑室移位或者消失
后颅窝血管母细胞瘤MR表现
囊性占位，稍微高信号的壁结节与柔脑膜关系密切，增强检查明显强化。
自旋回波序列显示流空信号区，病变周围或者肿瘤内可见异常的血管。
囊性部分可呈T1和T2的等或高信号。
囊壁边界清楚
MR征象的变异包括囊内出血，实性，多发病变，瘘管或则腔。
Key points:
• There is a differential for a cystic solitary, infratentorial mass which for an adult includes: hemangioblastoma, astrocytic tumor, and metastatic disease.
• Metastatic disease can look like anything. Look for mets in older patients.
• The most common primary infratentorial tumor in adults age 3-80 years old is hemangioblastoma.
• Most hemangioblastomas are cystic masses with a small enhancing nodule.
• Hemangioblastomas may be associated with von-Hipple-Lindau disease.
关键点：
成年幕下囊实性占位鉴别诊断包括：血管母细胞瘤，星形细胞瘤和转移。
转移瘤表现多样。老年男性要排除转移。
3~80岁最常见的幕下原发性肿瘤为血管母细胞瘤。
大多数血管母为大囊小结节。
血管母可能与VHL病有关。
History: Thirty-three-year-old male with new onset of nausea, vomiting, mild left weakness, right facial numbness, vertigo, and ataxia
30岁男性，新发恶心、呕吐、左侧轻度偏瘫、右侧面部麻木、眩晕和运动失调症状
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磁共振T2像
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FLAIR图像
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Findings: CT shows no acute abnormality. MRI shows hyperdensity in the left medulla and left posterior cerebellum on FLAIR and shows restricted diffusion. This is consistent with an acute infarct in the PICA distribution. MRA demonstrates absence of the left vertebral artery and its PICA branch
影像学表现：CT未显示异常。MRI的FLAIR图像显示左侧延髓和左侧小脑半球后部高信号，扩散受限。与小脑后下动脉的急性梗死相符合。MRA左侧椎动脉及其小脑后下动脉未显示
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Lateral medullary (Wallenberg) syndrome
半侧延髓综合征（wallenberg）综合征
The medulla is perfused by the PICA and by direct smaller branches from the vertebral arteries. The pons is perfused by small penetrating branches from the basilar artery and its major branches. Penetrating arteries from the PCA perfuse the midbrain and thalamus, and the occipital cortex is perfused by the PCA. At the base of the brain, the carotid and basilar systems join to form a circle of large communicating arteries, known as the circle of Willis. Because of this arrangement of collateral vessels, even when one of the main arteries is occluded, adequate perfusion of the brain still may be possible.
Usually, this syndrome is due to vertebral artery occlusion or, less commonly, to PICA occlusion. Because of the close anatomical relationship between the vertebral arteries and the cervical spine, chiropractic manipulation or neck rotation may traumatize the vertebral arteries in the neck. The damaged arteries may occlude with thrombus or undergo dissection.
Embolic occlusion of the vertebrobasilar system is not common and usually is artery-to-artery with occlusion of the basilar artery. Donor sites for the emboli typically are the aortic arch, the subclavian artery, and the origin of the vertebral arteries.
Patients present with nausea, vomiting, and vertigo from involvement of the vestibular system. Ipsilateral facial pain and temperature loss, Horner syndrome, ipsilateral ataxia, ipsilateral paralysis of the tongue, soft palate, vocal cord or sternocleidomastoid [SCM] muscle, and contralateral loss of pain and temperature
The prognosis of patients with the lateral medullary syndrome usually is quite good for functional outcome; however, patients may die in the acute phase from aspiration pneumonia, and death has been reported from sleep apnea in a number of cases.
A stroke involving the cerebellum may result in a lack of coordination, clumsiness, intention tremor, ataxia, dysarthria, scanning speech, and even difficulties with memory and motor planning. Early diagnosis of cerebellar infarctions is important since swelling may cause brainstem compression or hydrocephalus.
延髓由小脑后下动脉和椎动脉的小分支直接供血。脑桥由基底动脉及其大分支的穿支动脉供血。大脑后动脉的穿支灌注中脑与丘脑。枕叶皮层由大脑后动脉供血。在颅底，颈内动脉和基底动脉组成大的交通动脉，即willis环。因为这一侧枝循环的存在，及时发生一支大血管的阻塞，仍然能够保持脑的正常血液灌注。
通常，本病综合征是由于椎动脉阻塞，或者少见的小脑后下动脉阻塞造成。因为椎动脉和颈椎的解剖关系密切，按摩或者颈部旋转可以损伤椎动脉。受伤的动脉可以形成栓子或者动脉夹层。
椎基底动脉系统的栓塞不常见，通常是基底动脉的阻塞。栓子的来源可以是主动脉弓、锁骨下动脉和椎动脉的起始部。
累及前庭系统是时，病人表现为恶心、呕吐、眩晕。同侧面部疼痛和体温消失，霍纳综合征，同侧运动失调、半侧舌、软腭、声带、胸锁乳突肌瘫，对侧疼痛和体温消失。
半侧延髓综合征的功能预后良好，但是可以死于急性期的吸入性肺炎，部分病人死于睡眠中的呼吸暂停。
小脑的梗死可以导致协调性障碍，笨拙，震颤，运动失调，构音困难，断续语言，甚至记忆和行动困难。小脑早期诊断非常重要，因为水肿可以导致脑干的压迫和脑积水。
Radiologic Overview of the Diagnosis:
• Computed tomography (CT) usually is the first imaging study performed, as it has a sensitivity of more than 95% to identify intra-axial or extra-axial hemorrhage within the first 24 hours of onset.
o The disadvantages of CT scan include a low sensitivity for early ischemia and the presence of significant artifacts caused by the bony structures surrounding the brainstem and cerebellum.
o Other helpful findings include evidence of infarcts in the thalamus or occipital lobes implicating involvement of the rostral basilar artery and of the presence of a hyperdense basilar artery, suggesting a probable occlusion.
o Spiral CT angiography is used further to identify occluded and dolichoectatic vessels.
• Magnetic resonance imaging and magnetic resonance angiography
o Magnetic resonance imaging (MRI) is superior to CT scan in its sensitivity to identify ischemia (since bone does not degrade the image). Newer techniques, including flow suppression, diffusion, and perfusion-weighted images, make it a very powerful tool to exclude intraparenchymal hemorrhage or edema and to identify early and potentially reversible ischemia.
o MRI and magnetic resonance angiography (MRA) are very helpful in finding occult lesions such as demyelinating plaques, tumors, vertebrobasilar dolichoectasia, or dissection. MRA can identify vertebrobasilar occlusion with sensitivity up to 97% and specificity up to 98%. A limitation of the MRA is a tendency to overestimate the degree of stenosis. This overestimation occurs because the image of the vessel in MRA is a flow-related phenomenon; hence, severe stenosis with significant flow compromise may result in poor visualization of the vessel and may resemble vascular occlusion.
影像学诊断
通常首选CT检查，因为其对于发病24小时内的轴内外出血敏感性达95%以上。
• 缺点在于对于早期缺血不敏感，脑干和小脑存在骨性结构伪影。
• 其它有用征象包括丘脑或者枕叶梗死的证据，提示背侧基底动脉受累，以及基底动脉高密度，提示可能阻塞。
• 螺旋CT血管造影有助于进一步显示阻塞或者夹层的血管。
MRI和MRA
• MRI在发现缺血方面的敏感性高于CT，这是由于不受后颅窝骨性伪影影响的结果。新技术，例如流动补偿，扩散、灌注图像，在发现排除脑内出血、水肿、发现早期或者可逆性缺血方面功能强大。
• MRI和MRA在发现隐匿性病变方面非常有价值，例如脱髓鞘版块，肿瘤，椎基底动脉动脉过长迂曲或者夹层。MRA发现椎基底动脉的阻塞的敏感性高达97%，特异性高达98%。MRA的一个局限在于过度诊断狭窄程度。这种过度诊断是由于MRA成像原理在于流动相关增强造成的。因此，严重的狭窄难以观察血管，类似血管阻塞。
Key points:
• Wallenberg抯 Syndrome is also known as lateral medullary syndrome. The lateral medulla is affected.
• Symptoms include Horner抯 Syndrome, dysarthria, dysphagia, ipsilateral weakness, contralateral facial numbness, ataxia, nausea, vomiting.
• The arterial distribution affected is the PICA or vertebrobasilar system.
• The most common cause is atherosclerotic disease.
• In a young patient (< 45 years old) think of dissection of the vertebral artery at the C1-2 level. Think of trauma or an underlying condition such as Lupus or a coagulopathy.
关键点：
• Wllenberg综合征也名半侧延髓综合征。半侧延髓受累。
• 症状包括Horner综合征，构音困难，吞咽困难、同侧无力，对侧面部麻木，运动失调，恶心、呕吐。
• 小脑后下动脉和椎基底动脉受累
• 最常见的原因是动脉硬化性病变
• 年轻的病人（＜45岁）应该犒劳到C1-2水平椎动脉夹层的可能。考虑到外伤，或者其它病变，例如狼疮病和凝血性疾病。
History: Patient with confusion and aphasia
病史：病人意识混乱，失语
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FLAIR图像
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Additional clinical history: Before referral to this facility, the patient originally was thought to have herpes simplex viral encephalitis. The patient improved on a course of acyclovir, Decadron, and Keppra. However, the patient never returned to baseline mental status and continued to have symptoms of numbness of the face, neck, and hands. Over ensuring weeks, the patient became progressively confused and had difficulty with speech.
更多病史：转到本院前，病人按照病毒性脑炎治疗。经过阿昔洛维、地卡特隆、抗癫痫药物治疗，病人好转。但是病人始终不能完全恢复。持续存在脸部、颈部和双手麻木现象。接下来几周内，病人症状进行性加重，出现意识混乱，失语。
Differential diagnosis:
• Mutifocal glioma
• Metastases
• Multifocal infection / cerebritis (conceivably viral or embolic)
• CNS Lymphoma
鉴别诊断
• 多灶性胶质瘤
• 转移
• 多灶性感染、脑炎（病毒性或者栓塞性）
• 中枢神经系统淋巴瘤
Findings: Multiple enhancing masses with surrounding vasogenic edema and mass effect in the left cerebral hemisphere. There is associated sulcal effacement, gyral expansion/ thickening, and mass-effect with approximately 9 mm midline shift towards the right.
Diagnosis: Glioblastoma Multiforme.
影像学表现：左侧脑半球多发强化病灶，周围血源性水肿，具有占位效应。脑沟消失，脑回增厚，中线向对侧移位9mm。
诊断：多形性角质母细胞瘤
Glioblastoma Multiforme
• Glioblastoma Multiforme (GBM) is unfortunately both the most common and the most malignant of the glial tumors.
• Of approximately 17,000 primary brain tumors diagnosed in the US every year, 60% are glial tumors. Males have a slight predominance: 1.5 to 1.
• The world health organization classification:
o Grade II: low grade diffuse astrocytoma.
o Grade III: anaplastic astrocytoma.
o Grade IV: Glioblastoma multiforme.
• GBMs often arise in the subcortical white matter of the cerebral hemispheres. 31% arise in the temporal lobes. 24% arise in the parietal lobes. 23% arise in the frontal lobes and 16% arise in the occipital lobes. Sites such as the brain stem, cerebellum and spinal cord are much less common.
• Classically, GBM has a thick, irregular enhancing rind of neoplastic tissue which surrounds a necrotic core.
• The differential diagnosis for GBM includes:
o Abscess: ring enhancement is usually thinner than GBM.
o Metastases: usually multiple lesions at Gray-white junction.
o Anaplastic astrocytoma: Usually nonenhancing white matter mass. Enhancement may suggest degeneration to GBM.
o Primary CNS lymphoma: Periventricular enhancing mass which often crosses the corpus callosum.
o Tumefactive demyelination: Usually incomplete "horseshoe" enhancement which is open towards the cortex.
多形性角质母细胞瘤
• 多形性角质母细胞瘤技师最常见也是最恶性的胶质瘤。
• 美国每年诊断17000例原发性脑瘤。其中60%为胶质瘤。男性多发，男女比例1.5：1。
• 世界卫生组织分类标准
o II级：低度恶性弥漫型星形细胞瘤
o III级：间变性星形细胞瘤
o IV级：多形性胶质母细胞瘤
• 多形性胶质母细胞瘤常起源于大脑半球皮层下的白质。31%位于颞叶，24%位于顶叶，23%位于额叶，16%位于枕叶。脑干、小脑、脊髓病例罕见。
• 多形性胶质母细胞瘤的典型表现为：厚的环状强化肿瘤成分，包绕坏死成分。
• GBM鉴别诊断包括：
o 脓肿：环状强化部分比胶质母细胞瘤薄。
o 转移：通常位于灰白质交界处
o 间变性星形细胞瘤：通常不强化的白质肿块。强化代表向胶质母细胞瘤方向演化。
o 原发性中枢神经系统肿瘤：脑室周围的强化肿块，常穿过胼胝体。
o 肿瘤样脱髓鞘病变：常为不完整的“马蹄形”强化，开口向皮质。
20031030
History: Baby undergoing work-up for several systemic clinical abnormalities
病史：婴儿，全身性异常进行查体
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Findings: Images include T1 weighted pre and post contrasted sagittal images of the sella and three post-contrasted T1 weighted coronal images through the sella. The pituitary gland is somewhat smaller than expected. On the sagittal non-contrasted T1-weighted images, there is no posterior pituitary bright spot noted in the sella. There is, however, a hyperintense focus in the region of the tuber cinereum. No evidence of infundibular enhancement is noted on either the coronal or the sagittal images.
影像学表现：增强前后矢状面T1及冠状面增强后T1的鞍部图片。垂体的大小小于正常。在矢状平扫T1图像上，未见鞍部垂体后部高信号。但是灰结节区域出现局限性高信号。无论是矢状面还是冠状面都未见漏斗部异常强化病灶。
Diagnosis: Ectopic Posterior Pituitary
垂体后叶异位
Differential diagnosis would include:
Ectopic posterior pituitary.
Pituitary hypoplasia or agenesis
Empty sella syndrome.
鉴别诊断：
垂体后叶异位
垂体发育不全
空蝶鞍
Ectopic pituitary
Ectopic pituitary may result in pituitary dwarfism caused by deficiency of growth hormone. Characteristics include short stature, slow growth, defective dentition and delayed skeletal maturation. It is also associated with deficiency in multiple adenohypophyseal and neurohypophyseal hormones. Many cases are associated with perinatal asphyxia and disruption of the normal hypothalamic-pituitary axis. Traumatic transection of the stalk can also result in abnormal accumulation of posterior lobe hormones proximal to the disruption.
Many patients with agenesis of the pituitary gland or ectopic posterior pituitary gland present with breech presentation at birth. There also appears to be some association with other midline intracranial abnormalities and history of breech presentation. Two theories have been offered to explain this association. One presumes that the head trauma associated with breech delivery causes rupture of the pituitary infundibulum and with its vascular plexus. This does not explain the association with obvious congenital midline anomalies. Another suggests that fetal positioning and the normal progress of labor requires a normally functioning pituitary gland and normal midline structures.
垂体异位
垂体异位可以因为生长激素不足导致垂体性侏儒。特征包括身材短小、生长缓慢，牙裂缺陷也骨骼成熟延迟。可以具有多种腺垂体和神经垂体激素的不足。很多病例与围生期窒息这正常下丘脑－垂体轴的紊乱有关。垂体柄的外伤性夹层也可以导致外伤近端异常积聚垂体后叶外激素。
很多垂体发育不全或者垂体后叶异位的病人在生产时为臀位。臀位出生体位也于其它颅内中线结果的异常好像也存在一定关系。目前有两个理论来解释这一关系。一种理论认为臀位生产时的脑外伤导致垂体柄及其血管网破裂。但是这不能解释它与其它的明显中线结构异常间的关系。另一个理论认为儿童正常的出生体位以来与垂体的正常功能和中线结构的正常。
Radiologic Overview of the Diagnosis:
CT: May see small sella turcica and absence of pituitary stalk. Better seen on MRI.
MRI: Ectopic posterior pituitary hyperintense signal (EPP) is a marker of the so-called pituitary stalk transection syndrome. This syndrome is also characterized by the absence of pituitary stalk visibility and hypoplasia of the anterior hypophysis. EPP may also be associated with a visible pituitary stalk. It has been shown that the sensitivity of MRI for visualizing the pituitary stalk is increased by gadolinium injection and that the presence of an extremely thin pituitary stalk cannot be definitely excluded without enhancement. The presence of high signal intensity adjacent to the median eminence with absence of the normal pituitary bright spot within the sella on T1-weighted images is evidence for the ectopic pituitary.
影像学诊断：
CT：可能显示空蝶鞍和垂体柄阙如，MRI显示更佳。
MRI：异位的垂体后部高信号是垂体柄横断综合征的标志。该综合征的特征为垂体柄不显示及腺垂体的不发育。异位的垂体后部高信号存在时也可以存在正常的垂体柄。钆增强检查可以提高MRI显示垂体柄的敏感性，平扫MRI不能除外存在非常细的垂体柄的可能性。T1图像上发现临近中央隆起的高信号，而未见鞍内正常的垂体后叶高信号是诊断异位垂体的征象。
Key Points:
• In ectopic posterior pituitary the pituitary gland is somewhat smaller than expected and the normal posterior pituitary "bright spot" is located in the tuber cinereum of the hypothalamus.
• Patients with ectopic posterior pituitary often present with panhypopituitarism and require extensive hormone replacement therapy.
• There is an association between pituitary abnormalities including ectopic posterior pituitary, agenesis of pituitary and other midline intracranial abnormalities and breech presentation at birth.
关键点：
• 神经垂体异位是，垂体大小变小。正常垂体后叶的亮点位于灰结节或者下丘脑。
• 神经垂体异位的病人常表现为全垂体功能低下，需要大剂量激素替代疗法。
• 垂体功能异常（例如神经垂体异位、垂体不发育或者其它中线结构异常）和出生胎位存在一定关系。
看到一篇 转载如下:
Pulmonary and Peritoneal Ossification
A 20-year-old man, who had long-standing end-stage renal disease and was receiving peritoneal dialysis, presented with fever and abdominal pain. The patient began peritoneal dialysis at the age of 4 years because of a nephropathy of uncertain origin and subsequently underwent a renal transplantation, which failed. He had hypertension, had had multiple previous episodes of peritonitis, and had undergone a partial parathyroidectomy. Extensive calcifications were noted on radiographic evaluation, including increased opacification of the pulmonary interstitium on chest radiography (Panel A), extensive calcification within the interstitium on computed tomography (CT) of the chest (Panel -, and extensive peritoneal calcifications on abdominal CT (Panel C). On admission, his serum calcium level was 8.4 mg per deciliter (2.1 mmol per liter; normal value, 8.8 to 10.2 mg per deciliter [2.2 to 2.6 mmol per liter]) and his phosphate level 8.3 mg per deciliter (2.7 mmol per liter; normal value, 2.5 to 4.5 mg per deciliter [0.8 to 1.5 mmol per liter]). Peritonitis was diagnosed and was successfully treated with antimicrobial agents. Treatment was subsequently changed to hemodialysis. Widespread, or metastatic, calcification is a common complication in patients receiving long-term dialysis. Despite the radiographic findings, the patient, according to digital pulse oximetry, had an oxygen saturation of 98% while breathing ambient air and walking.
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Clinical history: Sixty-three-year-old female with swollen and painful right eye
女性，60岁，右眼肿痛
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CT图像
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磁共振图片如图
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Orbital Lymphoma
Orbital Pseudotumor
Thyroid Ophthalmopathy
Orbital Infections
Capillary or Cavernous hemangiomas
Optic Neuritis
Optic Nerve sheath meningioma
Optic Nerve glioma
Metastases
眼眶淋巴瘤
眼眶假瘤
甲状腺突眼
眼眶感染
海绵状血管瘤
视神经炎
视神经脑膜瘤
视神经胶质瘤
转移
Findings: Axial and coronal non-contrasted CT images through the orbits show a mass involving the anterior-inferior extraconal space of the right orbit extending into the right inferior orbital fissure and the right pterygopalatine fossa. The mass enhances on the contrasted neck CT images. Contrasted orbital MRI images with both thick and thin cuts demonstrate an enhancing soft tissue mass of the right orbit involving both the intraconal and extraconal compartments. The mass extends into the inferior orbital sinus, superior maxillary sinus, and the pterygopalatine fossa. The mass is hyperintense on T2-weighted images and hypointense on T1-weighted images.
Diagnosis: Lymphoma of orbit.
眼眶层面横断和冠状平扫CT显示：肿块累及右侧眼眶锥外间隙的前下部，延伸到右侧眶下裂和右侧翼腭窝。在颈部增强CT上，病灶强化。增强眼眶MRI薄层和厚层图像显示增强的右侧眼眶软组织肿块，同时累及眶内和眶外部分。肿块向眼眶下部、上颌窦和翼腭窝延伸。肿块呈T2高信号和T1低信号。
诊断：眼眶淋巴瘤。
Orbital Lymphoma
Lymphoid masses in the orbit are classified according to the histologically features as reactive lymphoid hyperplasia (pseudolymphoma), atypical lymphoid hyperplasia, and malignant lymphoma. Reactive lymphoid hyperplasia is mixed T-cell and B-cell type, while the malignant lymphomas consist mainly of B-cell lymphocytes. 30% to 35% of orbital lymphomas are associated with systemic lymphoma, usually non-Hodgkin抯 lymphoma. Once the diagnosis of orbital lymphoma is made by a biopsy, the workup for systemic disease must be performed.
Orbital lymphoid tumors have clinical signs and symptoms of proptosis, globe displacement, visual impairment, ptosis, diplopia, and mild motility disorders. Patients typically have orbital pain of the involved eye. The pain is usually slowly progressing and often accompanied with periorbital swelling. Females have a higher incidence, and the most common age of presentation is 50-70 years of age. Although any structure within the orbit can be involved, the extraocular muscles are typically spared.
Incisional biopsy is needed to make the diagnosis and to determine where on the spectrum of lymphoid masses each tumor falls. Orbital lymphomas are radiosensitive, and their response to treatment is often quite dramatic.
眼眶淋巴瘤
眼眶的淋巴样肿块根据组织学特征进行分类：反应性淋巴组织增生（假性淋巴瘤），不典型淋巴样组织增生，恶性淋巴瘤。反应性淋巴瘤增生是T细胞和B细胞混合性增生，而恶性淋巴瘤主要B淋巴细胞构成。30~35%的眼眶淋巴瘤是全身性淋巴瘤的一部分，通常发生于非何杰金氏病。一旦病理证实是眼眶淋巴瘤，必须进行全身检查，以除外系统性疾病。
眼眶的淋巴瘤临床特征和症状包括突眼，眼球异位，视力损害，眼睑下垂、复视、轻度运动异常。病人患侧眼疼痛，常为缓慢进行性，常伴眼球周围的肿胀。女性多发，发病年龄最常为50~70岁。虽然眶内的所有结构均可以受累。但是球外肌往往不受累。
确诊需要切除活检，确定肿瘤属于哪一种肿瘤。眼眶淋巴瘤对放疗敏感，治疗效果明显。
Radiologic Overview of the Diagnosis:
CT is usually adequate for evaluating orbital lymphoid lesions. Occasionally MRI can provide additional helpful information. Lymphoma commonly occurs in the extraconal compartment, often in the superior orbit. Lymphoma can obscure the superior rectus and levator palpebrae superioris muscles and displace the globe inferiorly. The tumor commonly molds around the globe, and it can infiltrate anteriorly to involve the lids and conjunctivae, although this is much less frequent. When Tenon抯 space is involved, there is apparent thickening of the posterior wall of the globe. Infiltration of the optic nerve sheath can create an appearance indistinguishable from preoptic neuritis or pseudotumor. Orbital lymphoma can cause bone destruction particularly when it extends out of the orbit via the superior and inferior orbital fissures and various foramina.
Lymphoid masses are typically hyperdense and homogenous on non-contrasted CT. They usually show mild to moderate enhancement. They are hypointense on T1-weighted images and hypointense to hyperintense on T2-weighted images with prominent gadolinium enhancement. Since there is an association with orbital lymphoma and systemic lymphoma, a workup to evaluate for lymphadenopathy within the chest, abdomen, and pelvis with a contrasted CT should routinely be performed.
Key Points:
Orbital lymphoma is associated with systemic lymphoma 30%-35%
Orbital lymphoma is often hyperdense with contrast enhancement
Orbital lymphoma is T1 hypointense and T2 hypo/hyperintense
Orbital lymphoma can involve any part of the orbit
Orbital pseudotumor is major diagnostic dilemma
Clinical history and exam are helpful in narrowing the differential
影像学诊断：
CT足以评价眼眶淋巴瘤病变。MRI可以提供更多信息。淋巴瘤常发生于眶内锥外，常见于眼眶上部。淋巴瘤可以导致上直肌和上睑提肌显示不清，眼球向下移位。肿瘤沿着眼球周围成形，少见情况下可以向前浸润眼睑和结膜。当累及Tenon空间是，球后壁可有假性增厚。视神经鞘浸润时难与视神经炎和假瘤鉴别。眼眶淋巴瘤可以导致骨性破坏，尤其是通过眶上裂和眶下裂以及其它各种孔钻出眼眶时。
淋巴样肿块密度高，在平扫CT上呈均匀密度。常为轻度到中度强化。MR呈T1低信号、T2高信号，明显钆强化。因为眼眶淋巴瘤与系统性淋巴瘤有关系，需要通过增强CT对胸部、腹部、盆腔淋巴结进行全面常规检查。
关键点：
30~35%的病理眼眶淋巴瘤与全身淋巴瘤相关。
眼眶淋巴瘤成为高密度，有强化。
眼眶淋巴瘤呈T1低信号、T2高信号或者低信号。
眼眶淋巴瘤可以累及眼眶的任何一部分。
眼眶假瘤是最主要的鉴别诊断。
临床病史和检查有助于缩窄鉴别诊断。
Seventy-year-old woman with headache.
病史，70岁女性，头痛
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横断和矢状图像如图
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Differential diagnosis for CPA mass:
• Acoustic neuroma
• Meningioma
• Epidermoid inclusion cyst
• Arachnoid cyst
• Aneurysm
• Choroid plexus papilloma
• Ependymoma
• Trigeminal neuroma
• Glomus jugulare tumor
• Metastases
桥小脑脚区肿物的鉴别诊断：
听神经瘤
脑膜瘤
表皮样囊肿
蛛网膜囊肿
血管畸形
脉络丛乳头样瘤
室管膜瘤
三叉神经瘤
颈静脉球瘤
转移
Findings: There is an extradural, dural based, enhancing lesion in the left cerebellopontine angle cistern that is isointense to the gray matter. It extends along the posterior margin of the petrous bone and passes through the hypoglossal canal into the parapharyngeal space (Annotated image). It displaces the internal carotid artery anteriorly. The tumor mass invades the temporal bone. There is homogeneous contrast enhancement
影像学表现：左侧桥小脑脚池内与灰质信号相同的硬膜外肿物，宽基底与硬脑膜接触。病变沿岩骨的后缘延伸，经过舌咽神经管进入咽旁间隙。向前方推压颈内动脉。肿瘤侵犯颞骨。病变均匀强化。
诊断：脑膜瘤
Meningiomas are the most common primary nonglial tumor of the CNS. They originate from arachnoid cap cells. Many are asymptomatic. There is a 3:1 female to male ratio and they are usually found in the 40 ?60 age group. 1-2% are malignant. Meningiomas are rare in childhood, but when found are often associated with neurofibromatosis type 2.
脑膜瘤是最常见的中枢神经系统非胶质细胞性肿瘤。它们来自蛛网膜颗粒细胞。大多数病变无症状。男女发病率3:1。多见于40~60年龄组，1-2%的病例为恶性。罕见与儿童，儿童脑膜瘤多于神经纤维瘤II型相关。
Although meningiomas are known to extend outside the central nervous system, it very rarely happens. Meningiomas have a distinct predilection for certain intracranial locations. Ninety percent are supratentorial. In addition, 45% are located in the cerebral convexity along and lateral to the falx. 20% are in the sphenoid ridge, 10% are juxtasellar, 10% are in the olfactory groove, and 10% are in the posterior fossa clivus.
虽然脑膜瘤可以向神经系统外延伸，但是比较少见。脑膜瘤具有好发的部位。90%的为幕上。45%位于大脑凸面大脑镰附近，20%位于蝶骨嵴，10%位于鞍旁，10%位于嗅沟，10%位于斜坡。
Radiologic Overview of the Diagnosis:
On CT, strong homogenous contrast enhancement is the hallmark. Most are hyperdense, but 25% are isodense to the brain parenchyma. Twenty percent have calcifications. Bony erosion may indicate malignancy. On MRI, meningiomas are typically isointense with gray matter and contain vascular flow voids. They have strong gadolinium enhancement and well-demarcated margins. A dural tail is suggestive of meningioma. On angiography, there is a spoke wheel appearance. The tumor blush comes early and stays late. The vascular supply is dural.
影像学诊断：
在CT上，典型表现为均匀明显强化。大多数为高密度，25%为等密度。20%的可以发生钙化。侵犯骨骼往往代表恶性。在磁共振上，脑膜瘤信号与灰质相同，并可见血管流空信号。钆增强检查明显强化，边界清楚，呈快进慢出。血供是硬膜性的。
Key points:
• On CT strong homogenous contrast enhancement is a hallmark.
• Greater than 95% of meningiomas are benign and many are asymptomatic.
• Ninety percent are supratentorial.
关键点：
CT表现均匀明显强化为特征。
95%的脑膜瘤为良性，大多数无症状。
90%的是幕上的。
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