脑血管病及颅内感染
脑血管病
HEMATOMA IN CT
血肿的CT表现
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Inatially, high attenuation. higher attenuation than
brain but less than bone (35-80 Hu).
Over several days to weeks, gradual decrease in
attenuation.
Hypodensity to cystic cavity.
ACUTE HEMATOMA急性血肿
mild edema轻度水肿
SUBACUTE HEMATOMA
亚急性血肿
CHRONIC HEMATOMA慢性血肿
HEMATOMA IN MRI
Acute (deoxyhemoglobin)急性期（脱氧血红蛋白 ）
T1WI: Isointensity to mild hypointense
等到低信号
T2WI: Very high hypointense高信号
Early subacute(intracellular methemoglobin) 亚急性
早期（细胞内高铁血红蛋白）
TIWI: Increasing hyper-intensity
T2WI: Hypo-intensity initially,
changing to
isointense
HEMATOMA IN MRI
Late subacute (Extracellular methemoglobin) 亚急
性晚期 （细胞外高铁血红蛋白）
T1WI: Hyper-intensity
T1WI高信号
T2WI: Hyper-intensity centrally
T2WI中
心高信号
Chronic (Hemosiderin-laden macrophages remain)
慢性期
（含铁血黄素）
A thin, hypointense rim appears
TIWI: Hypo-intensity decreases over time
T2WI: Rim of hypo-intensity increases,
central hyperintensity decrease,
leaving only a low signal intensity scar
ACUTE HEMOTOMA :DEOXYHEMOGLOBIN
ACUTE HEMATOMA
SUBACUTE HEMOTOMA
CHRONIC HEMATOMA
HEMOSIDERIN
慢性期（含铁血黄素）
CEREBRAL INFARCTION
脑梗塞
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The most common etiology of cerebral ischemia or
infarction in the adult is occlusion of an artery
resulting from either thrombus formation or
embolism, with atherosclerosis the most common
underlying cause在成人，脑缺血或脑梗塞最常见
病因是动脉闭塞，通常是血栓或动脉粥样硬化。
Carotid artery disease is especially common颈动脉疾
病尤其常见。
CEREBRAL INFARCTION
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ISCHEMIC INFARCTION缺血梗死
HEMORRHAGIC INFARCTION
出血性梗死形成
LACUNAR INFARCTION腔隙梗塞
Imaging appearance
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CT is often normal in the first few hours of infarction
or ischemia, sometimes for up to 24 hours. 在梗死或
缺血的最初几个小时，CT上通常表现为正常，
有时甚至至24小时。
Subtle effacement of sulci may be an important early
clue to infarction . 脑沟的细微消失可能是梗死的
重要征象。
Imaging appearance
Some of the very earliest signs of MCA or internal
carotid artery infarction on CT .
A. Loss of the insular strip of gray matter (loss of graywhite matter distinction)
B. Low attenuation in the ipsilateral caudate head if the
perforating arteries are also affected
C. A high attenuation MCA, representing clot within
the artery
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Imaging appearance
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With time, there is increasingly well-defined low
attenuation in an area of infarction because of
cytotoxic and vasogenic edema.
Mass effect 占位效应
Thrombotic infarctions often involve a large
vascular distribution, embolic infarctions
usually involve only a portion of a major
arterial territory.
The typical vascular distribution, often wedgeshaped and extending to the cortex.
Imaging appearance
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MRI is more sensitive than CT for early changes
of infarction, but in the first few hours after
vascular occlusion, MRI also may appear normal.
DWI, PWI may provide earlier evidence of
infarction.对梗死的早期变化MRI较CT敏感，
但是在血管闭塞最初的几个小时，MRI也可
是正常的。DWI，PWI能提供更早的梗死证
据。
T1WI --- low signal intensity低信号强度
T2WI --- high signal intensity高信号强度
FLAIR --- high signal intensity高信号强度
Loss of the insular strip of gray matter
Subtle effacement of sulci脑沟的微小消失
ACUTE INFARCTION
LOW DESITY and MASS EFFECT低密度和占位效应
SUBACUTE INFARCTION
LOW DENSUTY AND GYRIFORM ENHANCEMENT
CHRONIC INFARCTION
LOW DENSUTY and ATROPHY
ACUTE INFARCTION
LONG T1、 LONG T2 and MASS EFFECT
T1WI
T2WI
Flow-void effect
流空效应
CHRONIC INFARCTION
GYRIFORM ENHANCEMEMT
HEMORRHAGIC INFARCTION
出血性梗死形成
LACUNAR INFACTION腔隙性梗死
hyperacute infarction
梗死的超急性期
Acute infarction shows decreased diffusion, chronic
infarction showing increased diffusion.
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Clinical DWI can
identify acute
ischemic lesions
that are not
apparent on T2Weighted MR
images.
DWI能分辨出无
法在T2上显示的
急性缺血部分
INTRACRANIAL INFECTION
颅内感染
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The key diagnostic evidence in suspected meningitis comes
from cerebrospinal fluid analysis and culture, imaging has an
adjunctive role only.脑膜炎的主要诊断依据是脑脊液分析
和培养，图像仅仅是从属地位。
Imaging may detect processes such as abscess and encephalitis,
may localized focal conditions, and may help demonstrate the
progress or resolution of infection图像可以显示脓肿和脑炎
的征象，可帮助确定炎症的进展或消退。
INTRACRANIAL INFECTION
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Bacterial meningitis is common and is associated with serious
morbidity. 细菌性脑膜炎是常见的，有较高的死亡率。
Inflammatory exudates may obscure the subarachnoid cisterns on
noncontrasted CT, whereas meningeal enhancement may be
observed on CT or MRI following intravenous contrast material
administration. (meninges thickening)在非对比的CT上炎性渗
出物可以使蛛网膜下腔模糊，而给予静脉造影剂后脑膜增
强就可以在CT或MRI上观察到（脑膜变厚）
Lack of visible contrast enhancement does not exclude
meningitis.缺少可见的对比增强不能排除脑膜炎。
INTRACRANIAL INFECTION
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Imaging is important for evaluating complications of
meningitis.影像学评估脑膜炎的并发症是重要的
Communicating hydrocephalus交通性脑积水
Vasculitis or vasospasm血管炎或血管痉挛
Ischemia or infarction缺血或梗死
Subdural fluid collection硬膜下积液
Spread of infection (e.g. ventriculitis)感染扩散（脑室炎）
ABSCESS 脑脓肿
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Abscess of the brain usually begins as cerebritis.
Cerebritis is initially detected as an area of low
attenuation edema on CT or of high signal intensity on
T2WI and low signal intensity on T1WI MRI. With
time cerebritis progresses to abscess.
脑脓肿通常起始于脑炎。脑炎被最早发现是在CT
上是低密度的水肿区或在MRI上T2高信号影，T1
低信号影。随时间推移，脑炎可发展为脑脓肿。
ABSCESS
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Abscess wall is usually fairly thin and uniform, high
density on CT, low signal intensity on MRI脓肿壁在
CT上通常较薄，厚薄不甚不一致，呈高密度，在
MRI上则呈低信号。
Surrounding edema周围水肿
Central fluid attenuation or signal intensity
中心液化区呈水样信号强度
Well-defined ring-like pattern of enhancement
边界清楚的环状强化
ABSCESS
Abscess wall is usually fairly thin and uniform, high density on CT.
ABSCESS
Abscess wall is usually fairly thin and uniform
low signal intensity on MRI
The differential diagnosis between cerebral
abscess and cystic tumor
脑脓肿和囊性瘤的鉴别诊断
Bulk phase容积相
Abscess脓肿
Hydration layer水
Multiform glioblastoma
多形恶性胶质细胞瘤
TUBERCULOUS MENINGITIS
结核性脑膜炎
TUBERCULOUS MENINGITIS
结核性脑膜炎
meninges
thickening
脑膜增厚并强化
Cranial Trauma
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Skull颅骨
Penetrating injury穿透性损伤
Closed head injury闭合性头部损伤
Hemorrhage出血
Mass effect占位效应
Shift of intracranial structure颅内结构的移位
Secondary effects: 继发效应
infarction, hydrocephalus梗死，脑水肿
1. 脑挫裂伤
Gunshot枪弹伤
2. Intracranial hemorrhage颅内出血
•Extra-axial hematoma
Subdural hematoma硬膜下血肿
Epidural hematoma硬膜外血肿
subarachnoid hemorrhage蛛网膜下腔血肿
•Intraventricular hemorrhage脑室内血肿
•Intra-axial hematoma
Hematoma血肿
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Acute hemorrhage is usually dense (bright) on CT.
急性出血通常在CT上是高密度（亮的）
On MRI, the signal of hematoma is depended.
而在MRI上，血肿信号是不确定的
3. Epidural Hematoma
硬膜外血肿
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Usually result from arterial bleeding, often from
laceration of the middle meningeal artery by a
squamosal temporal bone fracture . However,
venous or mixed sources also may cause epidural
hematoma.
通常来自动脉出血，常见的是颞骨鳞部骨折导
致的脑膜中动脉破裂。但是静脉或者混合来源
的也可以导致硬膜外血肿。
Epidural Hematoma硬膜外血肿
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Extra-axial
Do not cross sutures不越过颅骨缝
Usually with convex margins or a lentiform
shape通常是凸面的或者是透镜状
Mass effect占位效应
Fracture骨折
lentiform shape凸透镜状
EPIDURAL HEMATOMA硬膜外血肿
Pneumatosis积气症
EPIDURAL
HEMATOMAS
4. Subdural Hematoma
硬膜下血肿
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Usually result from venous bleeding
通常来自静脉出血
The most common location is over the cerebral
convexities 最常见的位置是脑的凸面
Subdural Hematoma硬膜下血肿
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Extra-axial
May cross sutures可以越过颅骨缝
Usually extending widely across the convexity and
appear crescentic (new moon, luniform)通常越
过凸面，显示为新月形
Mass effect占位效应
Skull fracture (sometimes)颅骨骨折（有时）
extending widely across the convexity横跨脑的凸面
SUBDURAL HEMATOMA
SUBDURAL
HEMATOMA
SUBADURAL
HEMATOMA
先天发育畸形
DISPLASIA OF CORPUS CALLOSUM
胼胝体发育不良
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May be an isolated anomaly or part of a more extensive
malformation complex.
May be partial or complete agenesis.分为部分性或完全性
The interhemispheric lipomas are often bulky in the absence of
the corpus callosum.
DISPLASIA OF CORPUS CALLOSUM
Lateral ventricles have a more parallel
configuration, with crescent-shaped frontal
horns.
Occipital white matter is undeveloped .
Dilatation of the atria and occipital horns.
The third ventricle is usually dilated with
upward herniation to the interhemispheric
fissureAbsence of corpus callosun.
DISPLASIA OF CORPUS COLLUSUM
Lateral ventricles have a more parallel configuration,
with crescent-shaped frontal horns侧脑室平行，新月形前角
DISPLASIA OF CORPUS COLLUSUM
Absence of corpus callosun
课后复习题：
1、脑梗塞的影像学特点有哪些？
2、脑出血的影像学特点有哪些？
3、颅内感染的影像学特征。