What should I write in my medical image notes at work?

The density of human body structure is different, and this difference of tissue structure density is the basis of X-ray image affecting contrast, which is called natural contrast.

2. Manual comparison:

For tissues or organs lacking natural contrast, high-density or low-density substances can be artificially introduced to produce contrast.

3. Flow void effect:

When the flowing liquid such as blood flows rapidly in blood vessels, no signal can be collected during the imaging process, and it appears as a black shadow without signal.

4. Comparative inspection:

A contrast agent is introduced into an organ or its surrounding space to produce an artificial contrast, thereby imaging.

5, lung field (lung field):

The lungs filled with gas are even and transparent on the chest radiograph, which is called lung field.

6. hilum:

Pulmonary artery, segmental artery and lobar artery are at the root of lung, accompanied by the projection of bronchi and pulmonary veins.

7. Lung markers:

Dendritic shadows distributed radially from hilum can be seen in the lung field filled with gas, which consists of pulmonary veins and pulmonary arteries, mainly pulmonary arteries, but also lymphatic vessels, bronchi and connective tissues.

8. lung substantial:

Gas-containing gaps and structures with gas exchange function in the lung, including alveoli and alveolar walls.

9, lung interstitial (lung interstitial):

Scaffold and space composed of connective tissue around bronchi and blood vessels, alveolar septum, interlobular septum and visceral pleura.

10, cavity:

The diseased tissue in the lung is necrotic and liquefied, and the necrotic tissue is discharged through the drainage bronchus.

1 1, bronchogram:

Air bronchus sign, when the lesion extends to the hilum of the lung, the larger air bronchus is in contrast with the consolidation lung tissue, and the shadow of air bronchus can be seen in the consolidation area.

12, primary syndrome:

It is found in primary pulmonary tuberculosis caused by initial infection of Mycobacterium tuberculosis, including primary pulmonary lesions, lymphangitis and lymphadenitis. It is more common in children and adolescents, and a few are adults. X-ray: It is typically "dumbbell-shaped".

13, tuberculoma:

Circular and oval shadows, ranging in size from 0.5 cm to 4 cm, mostly 2.0 cm to 3.0 cm, with clear edges, smooth outline, occasional lobulation, high density, and spotted, layered and annular calcification inside. The common fibroproliferative focus around tuberculoma is called "satellite focus".

14, pleural depression:

Lung malignant tumors are mostly infiltrative growth with sharp edges and often short burrs protruding around them. When they are close to the pleura, linear, sporadic or stellate shadows can connect with the pleura, forming pleural depressions.

14, bone age:

In the process of bone development, the age of primary ossification center and secondary ossification center of bone and the age of metaphysis and epiphysis healing.

15, osteoporosis:

Bone mass per unit volume of bone decreases, that is, bone organic matter and calcium salt decrease in proportion.

16, Osteomalacia:

In osteon, the volume of calcium salt is reduced, the organic matter is normal, and the bone is softened.

17, loose area:

It is mostly found in the pubic branch and the upper femur, showing a cool line shape, about 1-2mm wide, with a slightly hard edge and perpendicular to the cortical bone.

18, periosteal triangle (Codman triangle):

With the development of malignant bone tumors, such as osteosarcoma, the formed periosteal new bone can be destroyed by the tumor, and sleeve-shaped residual periosteal new bone is formed on both sides of the destroyed area, which is called Codman Triangle.

19, epiphyseal fracture:

In childhood, because the epiphysis of long bones is not combined with the metaphysis, when an external force acts on the epiphysis or metaphysis, the epiphysis is separated.

20, greenstick fracture (green stick fracture):

Children's bones are flexible, and it is not easy for external forces to completely break the bones. X-ray film only shows local distortion of bone cortex and trabecular bone, no fracture line is found or only wrinkles, depressions or bulges of bone cortex are caused.

2 1, Colles fracture:

Distal radial extension fracture refers to a transverse or comminuted fracture within 2-3cm of the distal radius. The distal segment is displaced backward or radially, and the broken end is angled towards the palm, which may be accompanied by ulnar styloid fracture.

22, bones:

When the blood supply of bone cortex is damaged, necrosis may occur, which is manifested as a strip-shaped high-density bone block parallel to the long axis of bone.

23, osteosarcoma (osteosarcoma):

It is the most common primary malignant bone tumor, which originates from osteoblast mesenchymal tissue and is characterized by tumor cells directly forming osteoid tissue or bone.

24, Schmohl nodules:

The nucleus pulposus protrudes to the vertebral body, which can form a circular or semi-circular bone depression area above or below the vertebral body, and its edge is hardened, which is called Schmohl tubercle.

25. Xiaoshengying:

Due to the ulcer of digestive tract wall, the barium shadow with protruding outline formed by contrast agent filling is a quasi-circular high-density shadow in the axial direction, which is common in ulcers.

26, filling defects:

In contrast examination, the image of occupying lesions in digestive tract that cannot be filled by contrast agent is called filling defect, which is mostly caused by tumor, inflammatory granuloma and foreign body.

27, diverticulum:

Due to the weak tissue structure of the local gastrointestinal wall, the localized pocket-shaped protrusion formed by the pressure in the lumen, or the pocket-shaped protrusion formed by the adhesion of adjacent lesions outside the lumen, the mucosa in the lumen is continuous with the adjacent mucosa.

27, half moon syndrome:

The X-ray manifestations of gastric cancer are a niche shadow with irregular shape, mostly half-moon, flat outer edge and uneven inner edge, pointing to the periphery at acute angles of different sizes. There is a wide translucent belt around the niche shadow, which is called the "ring dike" sign. Nodular and finger-pressure filling defects are common in circular dikes, which is called semilunar syndrome.

28, meningeal tail sign:

When meningioma occurs, MRI examination shows that T 1WI shows equal or slightly high signal, T2WI shows equal or high signal, and the meninges are uniformly enhanced, and the adjacent meninges are also thickened and enhanced, which is called meningeal tail sign.

Short Answer Questions

1, contrast agent application and examples:

Contrast agent is used for contrast examination. High-density contrast agents such as barium and iodine; Low density contrast agent, such as gas. Barium agent is medical barium sulfate, which is mainly used for esophagography and gastrointestinal radiography. Iodine agents include organic iodine and inorganic iodine. Water-soluble organic iodine is mainly used for cardiovascular angiography; Renal pelvis and urinary tract can be displayed by renal excretion; Myelography is also feasible. Water-soluble organic iodide can be divided into subtypes (meglumine diatrizoate, toxic) and nonionic (Pierer iodine, iohexol -Onaipak).

2, lung field nine points method:

Draw a horizontal line from the lower edge of the front ends of the second and fourth anterior ribs, and divide each lung field into upper, middle and lower lung fields. Divide the lung field into three equal parts longitudinally, and divide each lung field into inner, middle and outer zones; 1 The part within the outer edge of the rib ring is called the lung apex area, and the part below the clavicle within the outer edge of the second rib ring is called the subclavian area.

3. Mediastinal gender short message method:

Draw a horizontal line from sternal angle to the lower edge of the fourth thoracic vertebra on the lateral chest radiograph, with the upper mediastinum above and the lower mediastinum below; The front of trachea, ascending aorta and heart is the anterior mediastinum, the position occupied by trachea and heart blood vessels is the middle mediastinum, and the esophagus includes the posterior mediastinum.

4. Normal mediastinal CT:

Thoracic entrance level (internal static neck, subclavian static, brachiocephaly static, right brachiocephaly trunk, right carotid artery, subclavian artery), sternal stalk level (aortic arch, right anterior-left posterior: brachiocephaly trunk, left common neck, left subclavian, left and right brachiocephaly static), aortic arch level (superior vena cava, aortic arch) and main pulmonary artery window level (aortic arch)

5, lung lesions:

Exudation and consolidation, cavities and cavities, nodules and masses, interstitial lung lesions, fibrosis and calcification.

6, pleural lesions:

Pleural effusion; Pneumothorax and hydrothorax; Pleural hypertrophy, adhesion and calcification; Pleural mass

7, lung abscess infection route:

Direct transmission of inhalation, blood-borne and adjacent organ infections.

8. CT manifestations of bronchiectasis:

⑴ Columnar dilatation: the bronchial wall thickens and the lumen widens. When there is gas in the lumen, the dilated bronchi parallel to the CT section show a "trajectory sign", and when they walk perpendicular to the CT section, they can show a circular translucent shadow of the tube wall, showing a "ring sign"; ⑵ Cystic dilatation: multiple and clustered cavities are grape-shaped with liquid level inside; ⑶ Varicose dilatation: The dilated bronchi are uneven in thickness and beaded.

9. X-ray manifestations of lobar lung:

⑴ Stagnation: No positive findings were found in the early stage, or only the lung texture in the lesion area increased, the transparency was slightly lower, or the fuzzy shadow was slightly higher. ⑵ consolidation stage: dense shadows with uniform density, and the lung segments involved in inflammation are flaky or triangular dense shadows; Involving the whole lung, it shows a large dense shadow bounded by pulmonary fissure, and sometimes there is a bright bronchial shadow in the dense shadow, that is, bronchial inflation sign. ⑶ Dissipation stage: the density of consolidation area decreases gradually, and the lesions may present patchy shadows with different sizes and irregular distribution due to uneven dissipation.

10, X-ray manifestations of bronchopneumonia;

(1) The lung texture in the middle and lower fields of both lungs is blurred and there are small patches of fuzzy shadows; ⑵ The flaky fuzzy dense shadows are distributed along the lung texture; ⑶ Small plaques can be merged into large plaques.

1 1, classification of tuberculosis:

Primary tuberculosis (primary syndrome), disseminated tuberculosis, secondary tuberculosis, tuberculous pleurisy and other extrapulmonary tuberculosis.

Typical X-ray signs of primary pulmonary tuberculosis: primary focus; Lymphangitis; Lymphadenitis, hilar and mediastinal lymphadenopathy

12, X-ray film of infiltrative pulmonary tuberculosis:

Localized patchy shadows, lobar caseous pneumonia (large dense consolidation area with "insect-eaten" cavities, round), proliferative lesions (patchy shadows arranged in plum petals or tree buds), tuberculoma, tuberculous cavities, disseminated bronchial lesions, calcification of peduncle and thickening of interlobular septa.

13, X-ray manifestations of central lung cancer:

Direct signs: the hilar shadow deepens and expands, and the mass shadow protrudes from the hilar area.

Indirect signs: ① Obstructive pneumonia: repeated inflammation in the same segment; ⑵ Obstructive emphysema: segmental emphysema with extremely short duration; ⑶ Obstructive atelectasis: The diseased lung shrinks centripetally, with smaller volume and higher density. The central lung cancer in the right upper lobe, the lower edge of atelectasis in the right upper lobe and the hilar mass constitute a special transverse "S" sign.

Signs of metastasis: ① lymph node metastasis, mediastinal hilar lymph node enlargement; ⑵ Blood metastasis, diffuse nodules of different sizes in the whole lung; ⑶ Pleural effusion, pericardial effusion and multiple bone metastases.

CT manifestations of central lung cancer: ① Bronchial changes: mainly including thickening of bronchial wall and stenosis of bronchial cavity; (2) hilar mass: lobulated or irregular-edged mass, often accompanied by obstructive pneumonia or atelectasis; (3) Invasion of mediastinal structure: The invaded blood vessels in mediastinum can be manifested as compression and displacement, narrowing or occlusion of lumen and irregular wall; ⑷ Metastasis of mediastinal hilar lymph nodes.

14, mediastinal mass location and common diseases:

⑴ Thoracic entrance area: Most adults are thyroid tumors, and children are often lymphangiomas; ⑵ Anterior mediastinum: thymomas and teratomas are common, and the masses in the anterior diaphragm angle are mostly lipomas and pericardial cysts; ⑶ Mediastinal region: Lymphoma is common, followed by bronchial cyst; ⑷ Posterior mediastinum: Neurogenic tumors are more common because of abundant nerve tissue; (5) Others: Aortoplasty area, usually tortuous dilatation, aneurysm and aortic dissection; Most patients with abnormal esophageal barium meal examination are esophageal tumors.

15, X-ray manifestations of acute suppurative osteomyelitis:

(1) soft tissue changes (1) strip or reticular shadows with slightly higher density appeared in subcutaneous fat layer; ② The subcutaneous fat layer and muscle space are blurred or disappeared; ⑵ Bone destruction ① Localized osteoporosis in metaphysis; ② Multiple scattered in irregular bone destruction area with blurred edges; (3) Bone destruction spreads to the bone shaft, and the scope is enlarged, reaching 2/3 of the whole bone or the whole bone shaft, forming a large-scale destruction, and the bone cortex can also be destroyed; ④ Pathological fracture; ⑶ Periosteal reaction: Layered or banded new bone parallel to cortical bone appeared outside cortical bone; ⑷ Dead bone: When the blood supply of cortical bone is damaged, necrosis will occur.

16, Differential diagnosis of suppurative arthritis and suppurative joint tuberculosis;

Course of disease: acute onset and short course of disease; The onset is slow and the course of disease is long; Clinical symptoms: fever, local swelling and pain, dysfunction; Joint swelling, pain and dysfunction; The destruction of articular cartilage and bone: it progresses rapidly, and the destruction of bone end begins in the bearing part of joint and accumulates widely; The progress is slow, and the destruction of bone end begins at the edge of joint; Narrowing of joint space: early appearance; Late arrival; Postarticular changes: ankylosis of bone and joint; Fibrous rigidity; Soft tissue changes: rare soft tissue atrophy; There is a lot of soft tissue atrophy.

17, differential diagnosis of benign and malignant bone tumors;

Growth situation: it grows slowly and does not invade adjacent tissues, but it can cause compression and displacement without metastasis; Rapid growth, easy to invade adjacent tissues and organs, accompanied by metastasis; Local bone changes: expansive bone destruction, clear boundary with normal bone, sharp edge, thinning and swelling of bone cortex, maintaining its continuity; Infiltrating bone destruction, the boundary between the lesion area and normal bone is blurred, and the edge is uneven, involving cortical bone, causing irregular destruction and defect, and there may be tumor bone; Periosteal hyperplasia: generally there is no periosteal hyperplasia, but there is a little periosteal hyperplasia after pathological fracture, and the new periosteal bone is not destroyed; Periosteal hyperplasia has many different forms, which can be invaded and destroyed by tumors. Peripheral soft tissue changes: no swelling or lump shadow, if there is a lump, the edge is clear; It can invade soft tissue to form a mass, and the boundary with surrounding tissues is unclear.

18, giant cell tumor of bone:

Long bone ends of limbs are common in the lower femur, upper tibia and distal radius.

The most common sites of osteosarcoma are the lower femur, the upper tibia and the upper humerus. 、

19, X-ray manifestations of joint tuberculosis:

⑴ Osteogenic joint tuberculosis: It is caused by epiphyseal tuberculosis invading the joint. Signs of epiphyseal tuberculosis, swelling of soft tissue around joints, destruction of articular surface or asymmetric narrowing of articular space, etc. ⑵ Synovial joint tuberculosis: ① At the early stage, the volume and density of joint capsule and soft tissue around the joint increased, and the joint space became normal or slightly widened; ② Chronic progressive joint space stenosis; ③ Bone destruction: Wormlike bone destruction at the edge of articular surface or non-load-bearing parts of articular surface; ④ Joint subluxation can be seen; ⑤ Osteoporosis, atrophy of adjacent bones and soft tissues; ⑥ Late stage: the bone destruction stops, the lesion heals, and fibrous rigidity may appear.

20. X-ray manifestations and types of osteosarcoma:

⑴ Overall manifestations: bone destruction, periosteum proliferation destruction, tumor bone and soft tissue mass;

(2) Typing manifestations: ① Osteogenic osteosarcoma: mainly tumor bone with ivory-like dense shadows in different ranges; Patchy or needle-like tumor bones can also be seen in soft tissue masses; The early cortical bone was intact, but it was later destroyed. ② Osteolytic osteosarcoma: mainly bone destruction with little or no tumor bone; Most of the lesions were on one side, showing irregular patches or large osteolytic lesions with unclear boundaries; Periosteal new bone is easily destroyed by tumor, forming periosteal triangle; There is no or a small amount of tumor bone in the soft tissue mass; Pathological fractures are prone to occur. ③ Mixed osteosarcoma: destruction of tumor bone and osteolytic bone can be seen; Tumor bones are mostly flocculent; Tumor bone can also be seen in the extraosseous soft tissue mass; Periosteal hyperplasia and periosteal new bone destruction have different degrees.

2 1, X-ray manifestations of spinal tuberculosis:

① Vertebral destruction: it can occur at the center or edge of the vertebral body, and the vertebral body collapses and becomes flat or wedge-shaped; ② Narrowing or disappearance of intervertebral space: intervertebral disc accumulation after lesion destroys the upper or lower edge of vertebral body; ③ kyphosis or scoliosis often occurs in the involved spinal segments; ④ Paravertebral abscess: psoas major abscess (arc), thoracic paravertebral abscess (spindle) and retropharyngeal abscess (arc).

22. The X-ray manifestations of suppurative arthritis:

① In acute stage, the soft tissue around the joint swells and the joint space widens, which can cause joint subluxation; ② Osteoporosis of joint components; ③ The destruction of articular cartilage can narrow the joint space; ④ The subchondral bone of joint was destroyed, and the weight-bearing part appeared early or obviously; ⑤ During the healing period, bone destruction stopped, and reparative hyperosteogeny appeared in the lesion area. Severe ankylosis

23. X-ray manifestations of long bone tuberculosis (metaphyseal tuberculosis):

① Early stage, localized osteoporosis in cancellous bone; ② There is no obvious bone hyperplasia in the metaphyseal end or the limited circular bone destruction area across the epiphyseal line, and the periosteal reaction is rare or slight; ③ "silt-like" dead bone, which is clastic, with low density and blurred edges; ④ Destruction of bone cortex, periosteum and soft tissue abscess to form fistula, causing secondary infection.

24. Abnormal manifestations of gastric barium contrast:

⑴ Contour changes: niche shadow, filling defect and diverticulum; ⑵ Changes of mucosa and mucosal folds: mucosal destruction, flat mucosal folds, widened and tortuous mucosal folds, and gathered mucosal folds; ⑶ Functional changes: changes in tension, peristalsis, exercise force and secretion function.

25. X-ray signs of gastric ulcer:

⑴ Direct X-ray signs: niche shadow (flat bottom, smooth edge), clear edema zone at the mouth of niche shadow (mucosal line sign, collar sign, neck stenosis sign), mucosal bundle (wheel); ⑵ Indirect X-ray signs: spasmodic changes, increased secretion, abnormal gastric motility and tension, and scar changes (snail-shaped, gourd-shaped stomach and pyloric tube ulcers can cause pyloric stenosis and obstruction); ⑶ Special gastric ulcer manifestations: penetrating ulcer, perforated ulcer and corpus callosum ulcer.

26. X-ray manifestations of advanced gastric cancer:

① Hyperplastic type: mainly a large number of filling defects with eccentric lumen stenosis; ② Infiltration type: symmetrical stenosis of lumen (annular stenosis). "Skin stomach" —— Gastric cancer grows diffusely and infiltratively on the stomach wall, involving most or all of the stomach, causing diffuse thickening of the whole stomach wall, stiffness of the stomach wall and narrowing of the stomach cavity; ③ Ulcer type: obviously irregular or crescent-shaped niche in the cavity.

27, differential diagnosis of gastric benign and malignant ulcer:

Position of niche shadow: outside the outline of stomach, completely or mostly in the stomach cavity; Shape of niche shadow: round or oval, irregular, flat, with sharp corners; Niche size: mostly less than 2cm, mostly >; 2.5cm niche shadow edge: smooth and neat, not only integral, but also full of defects; Niche shadow mouth: mucosal edema, mucosal line, collar sign, narrow neck sign, itchy finger impression filling defect, irregular ring dike; Mucosa around niche shadow: aggregation, destruction and interruption; Adjacent to stomach wall: soft, with peristalsis wave, hard, without peristalsis wave.

28, the differential diagnosis of antritis and gastric cancer:

Outline: neat and irregular; Mucosa: thickening, tortuosity, disorder, destruction, middle section and disappearance; Mass: none, yes; The boundary between diseased area and normal area: no obvious boundary, complete decomposition; Elasticity of stomach wall: soft, changeable and fixed in shape, rigid in stomach wall; Creep: Creep wave and creep wave disappear.

28, liver CT enhanced scanning abnormal performance:

(1) hepatocellular carcinoma: a tumor with multiple blood supply, characterized by "fast forward and fast out"; ⑵ Cavernous hemangioma of the liver: "Fast forward and slow out"; ⑶ Liver abscess: The abscess wall can be enhanced by double density ring; (4) Low blood supply tumor: no definite enhancement, always low density; 5] Cyst: no enhancement at all, always low density like water; (6) Portal vein tumor thrombus: low density filling defect in portal vein.

29, CT of hepatic cavernous hemangioma:

⑴ Plain scan: a round or quasi-round low-density mass with clear inner boundary of liver parenchyma; ⑵ Enhanced scanning starts from the periphery and extends to the center, and the enhancement density is close to that of the great vessels in the same layer; ⑶ After delayed scanning, the focus continued to strengthen for a long time and finally formed the same density as the surrounding normal liver parenchyma.

30, hepatocellular carcinoma CT:

(1) often has cirrhosis background; ⑵ Nodular type: single or multiple, round or quasi-round, irregular masses with clear edges, mostly low density; Block type: the density of central necrosis is low, and the density of bleeding or calcification is high; Diffuse type: Nodules are widely distributed with unclear boundaries. ⑶ enhanced or dynamic enhanced scanning: arterial phase: obvious patchy and nodular early enhancement appeared in the mass. Portal vein phase: tumor enhancement density decreased rapidly; Equilibrium period: As the tumor enhancement density continues to decrease, it returns to the original low-density state and "fast forward and fast out".

3 1, liver metastasis CT:

⑴ Plain scan: Single or multiple round or quasi-round low-density masses in the liver with uniform density, high-density lesions when calcification or bleeding occurs, and low-density lesions when liquefaction necrosis and cystic degeneration occur; ⑵ "bull's-eye sign": the center of the tumor is low-density without enhancement, the edge is high-density, and the periphery is slightly low-density edema zone.

32, liver cirrhosis CT:

⑴ Changes of liver size: The liver can be enlarged in the early stage, and the liver lobe can be enlarged or reduced in the middle and late stage of liver cirrhosis, and the proportion of liver lobe size is out of balance; ⑵ Changes of liver contour: the edge of the liver is uneven and the liver fissure is widened; ⑶ Changes of liver density: Fatty degeneration and fibrosis can cause diffuse or uneven decrease of liver density, and regenerative nodules are scattered in slightly high density nodules. Enhanced scanning showed that the enhancement degree of regenerative nodules was consistent with the liver parenchyma.

33, pancreatic cancer CT:

(1) local enlargement and mass formation of pancreas: mostly isodensity or low density, enhanced to low density; ⑵ Bile ducts and pancreatic ducts inside and outside the liver are dilated to varying degrees (double duct sign); (3) Gallbladder enlargement and hydrops; ⑷ Enhanced scan: The arterial tumor showed homogeneous or heterogeneous low-density lesions with irregular ring enhancement; Low density lesions in venous phase.

34, please describe the CT differential diagnosis of liver abscess and liver cyst:

The plain scan of liver abscess shows a round or quasi-round low-density area in liver parenchyma, with uniform or uneven density. CT value is higher than water or lower than normal liver parenchyma. Some bubbles or liquid level can be seen, and the abscess wall around the abscess cavity can be seen. In the acute stage, the abscess wall showed annular enhancement, but the abscess cavity was not enhanced. Peripheral edema zone can delay the enhancement of low-density abscess cavity, and annular enhancement of abscess wall and edema zone forms "ring sign" and abscess. Hepatic cyst is a round low density lesion with smooth edge and clear boundary, showing water-like density. Enhanced scanning has no enhancement, the boundary is clearer, and the wall thickness is generally not displayed. It is not difficult to distinguish the two after enhanced scanning.

35. Signs of gallbladder cancer:

⑴X-ray: gallbladder cancer invaded bile duct, PTC showed irregular stricture, filling defect and obstruction of bile duct; ⑵ CT: ① irregular thickening of gallbladder wall; ② Single or multiple nodules protruding into the cavity; ③ Intracavitary mass can fill the whole gallbladder and invade adjacent tissues and structures; ④ Bile duct dilatation inside and outside the liver can be displayed; ⑤ Irregular thickening of gallbladder wall or obvious enhancement of mass during enhanced scanning; ⑥ Some cases can show gallstones; ⑶ MRI: T 1WI shows inhomogeneous low signal intensity, T2WI shows inhomogeneous high signal intensity, and inhomogeneous enhancement may occur after enhancement. If low-signal stones are found in gallbladder, it is helpful to diagnose gallbladder cancer.

36, brain CT (basic lesions of the central nervous system):

Density changes: ① plain scan: ① high density lesions: hematoma, calcification, hemangioma; ② Isodensity lesions: tumor, hematoma, cerebral infarction absorption period; ③ Low density lesions: cystic degeneration, necrosis, gas, brain edema, softening focus, cholesteatoma, lipoma and astrocytoma; ④ Mixed density lesions: tumor, contusion and laceration, vascular malformation, etc. ⑵ Enhanced scanning: ① Uniform enhancement: meningioma, aneurysm, granuloma and metastasis; ② Uneven enhancement: glioma, vascular malformation, etc. ③ Annular enhancement: brain abscess, tuberculoma, glioma and metastasis; ④ No enhancement: encephalitis, cyst and edema.

Changes of the second ventricle, cistern and sulcus: (1) supratentorial space occupying lesions; ⑵ Subtentorial space occupying lesion: deformation and displacement of the fourth ventricle; (3) Occupying lesions of posterior cranial fossa: the third ventricle, bilateral ventricle enlargement; ⑷ Enlargement of ventricles, cisterns and sulcus: brain atrophy and brain softening.

37, abnormal brain MRI signal:

(1) Double SMS number: melanoma; ⑵ Double low signal: blood vessels are empty and completely calcified; ⑶ Double high signal: lipoma and cerebral hemorrhage in subacute stage; ⑷ Double signals: most primary brain tumors, metastatic tumors, brain abscesses, infarct foci, softening foci, edematous demyelinating lesions, arachnoid cysts and cholesteatoma; 5. Other signals: craniopharyngioma -T 1WI is high or low, T2WI is high, hemosiderosis, normal ferritin deposition (T 1WI is low), acute cerebral hemorrhage -T 1WI is low or slightly low, T2WI is low.

38, signs of meningioma:

⑴CT findings: On plain scan, a round or quasi-round high-density mass shadow with clear boundary can be seen, and irregular calcification can be seen in it. The broad base is connected with the dura mater or cranial plate, and the edema around the tumor is mild, with cortical buckle sign or white matter collapse sign, and hyperosteogeny and sclerosis can be seen near the cranial plate. Most meningiomas were obviously enhanced evenly on enhanced scanning. ⑵MRI findings: Typical meningiomas showed isocortical T 1 and T2 signals, and the enhanced scanning was obviously uniform and enhanced, with meningeal tail sign.

39. CT manifestations of cerebral hemorrhage:

⑴ Acute phase: Hematoma showed high-density shadow with CT value of 60-80 Hu; ⑵ Absorption period: from the second week of bleeding, the high-density centripetal contraction, blurred edge, became equal density or low density in the fourth week; ⑶ Capsule formation stage: Hematoma is completely absorbed, forming a low-density capsule with clear edge.