医学影像学：放射学(医学影像)课件.ppt

1、RADIOLOGY(Medical Imaging)Overview and Principles of Diagnostic ImagingMedical ImagingDiagnostic ImagingInterventional RadiologyDiagnostic RadiologyUltrasonographyNuclear ImagingDiagnosisTherapyMagnetic Resonance The aim of our course is mainly to study the basic knowledge about diagnostic radiology

2、:how to use x-rays,what can x-rays do for diagnosis of diseases,the various examination modalities,and what are the advantages and limitations of these examination modalities.Although a brief introduction of magnetic resonance(MR)is included in our course,ultrasound(US)and nuclear imaging will be ta

3、ught in additional courses.Diagnostic Imaging Methods Diagnostic imaging is a dynamic specialty that has undergone rapid change with continuing advancements in technology.Not only has the number of imaging methods increased but each one continues to undergo improvement and refinement of its use in m

4、edical diagnosis.Radiographic Techniques The principle of selectionPrinciples of x-rayThe x-ray beam is produced by bombarding a tungsten target with an electron beam within an x-ray tube.As x-ray pass through the human body they are attenuated by interaction with body tissues(absorption and scatter

5、),resulting in an image pattern recognizable as human anatomy.natural contrast artificial contrastRadiographic Techniques X-ray film Fluoroscopy Soft beam radiography for breast Contrast administration examinationRadiographic Techniques Contrast administration examination contrast medium Higher dens

6、ity contrast：barium，iodine Lower density contrast：gas agents The way of contrast administration direct：take orally、enema、inject into the vessels indirect：inject into the veins，physiological excretionDigital Radiography DR1.Computed Radiography CR，(imaging plate IP)2.Digital Fluorography，DF(影像增强电视系统，

7、IITV)3.Digital Radiography,DR(flat panel detectors)Principle of CRPrinciple of DR PACS Picture Archiving and Communicating System RIS Radiological Information System RISPACSWebPACS 示意图示意图Digital Subtraction Angiography(DSA)Principle of DSA Imaging A method for showing contrast-filled vessels without

8、 any interfering background.“Mask”image,just before the contrast medium is injected,onto which the images with contrast medium were overlaid to coincide,producing a subtraction image only displaying the contrast-filled vessels.angiographyComputed TomographyIntroduction Since its introduction in the

9、1970s,CT has been shown to have wide applications within all the radiological subspecialities.It has become a primary imaging technique in the clinic.What is CT CT images a section or slice of the patient Two-dimensional image of the slice Reconstructed image(array of quantized gray scale values or

10、pixels)Pixel values(CT number)are related to the linear attenuation of the corresponding volume element of the slice(voxel)Basic Components of a CT GantryTableGeneratorConsoleComputerFrom the outside.TableGantryGeneratorInside a scannerTubeDetectorDASTube collimatorHow does a CT work Image Processin

11、gData detection&acquisitionX-ray sourceAir-1000H Sinus、mastoid cell-600H Lung-500H Fat-100H CSF 135H White matter 325H Gray matter 375H Blood 1080H Fresh hematoma 100H Soft tissue 50150H Calcified lesion Between soft tissue and bone Bone+1000H CT value图像质量的进展图像质量的进展.二二 维维 横横 断断 面面 到到 三三 维维 图图 像像 重重

12、建建 Equipment Conventional CT Spiral(helical)CT Multislice CT(MSCT)Electron beam CT(EBCT)Dual source CT(DSCT)Multislice CT（MSCT）Multislice CT,also known as multidetector CT(MDCT)or multidetector row,is the latest breakthrough in CT technology.It has trans-formed CT from a transaxial cross-sectional t

13、echnique into a true three-dimensional imaging modality.Major attributes that are improved are the z-axis coverage speed and the longitudinal resolution(isotropic arrays).Multi-Slice vs.Single Slice TechnologyKey benefits of multi-slice CT over single slice scanners increased coverage in a single br

14、eathhold better image quality decreased acquisition time thinner slices improved 3D post processing techniquesClinical Benefits of Multislice CTShorter Scan Time0.37sLarger VolumeClinicalApplicationIsotropic Resolution0.4mm多层多层CTCT发展迅猛发展迅猛 19921992：2 2层层 1998 1998：4 4层层 2001 2001：1616层层 2003 2003：64

15、64层层 20052005：双源：双源 2006:256 2006:256层层 2007:320 2007:320层层 单源单源CT 双源双源CTSOMATOM Definition世界首台双源CT任意心率条件下的时间分辨率83 ms=83 msRotation Time4Temporal Resolution =CT Techniques plain scanning contrast enhancement other contrast examination HRCT(high resolution computed tomography)HRCTCT TechniquesReconst

16、ruction Surface Shaded Display (SSD）Maximum Intensity Projection (MIP）Volume Rendering (VR）Multiplanar Reconstruction (MPR）Curved Multiplanar Reconstruction (CMPR）Virtual Endoscopy (VE）齿状突骨折伴环枕、环枢关节脱位齿状突骨折伴环枕、环枢关节脱位Fracture of the odontoid process with dislocation of the atlanto-occipital and atlant

17、o-axial jointsHeadlinestenosisCourtesy of University of Erlangen,Department of Radiology and Institute of Medical Physics SOMATOM Sensation 646 sec for 350 mm64 x 0.6mm(2x32)Resolution 0.4 mmRotation 0.37 sec120 kV/150 mAs缺乏造影剂？缺乏造影剂？扫描比造影剂扫描比造影剂跑得快！跑得快！Aneurysm and Dissection CTA of living donor tr

18、ansplantation CT TechniquesFunction and other techniques Perfusion Quantitative CT(QCT)CT coronary artery angiography Function 常 规 CT Time to Peak CBF 随 访 颅 内 动 脉 栓 塞 随 访 CT 显 示 液 化 灶embolism of intracranial arteries,follow-up CT image shows the infarctionmale,56,150min after the onset左前降支狭窄左前降支狭窄Le

19、ft anterior descending branch stenosisCT coronary artery VESpeed 4D-Cardiac Imaging with 0.37 s RotationImproved Diagnostic Confidence for Plaque AnalysisCourtesy of Thorax Center Rotterdam,the Netherlands扫描层厚、空间分辨率和冠脉成像SOMATOM Sensation CardiacCardiac MorphologyAdditional Clinical Information recei

20、ved from ECG-gated scan Calcified ThrombusAortic ValveECG-Gated Scan16-Slice Cardiac Function Analysis syngo Argus,CT 4D and LV-FunctionCourtesy of Grosshadern Clinic EF EDV ESV Mass Wall Thickening MovieCompatible to MRI and CT DataHeadlineSpeed 4D-Cardiac Imaging with 0.37 s RotationImproved Diagn

21、ostic Confidence for Plaque Analysis 6 months follow up of stent patency,no in-stent re-stenosis,67 bpm16x0.75 mm,185 ms,12 cm in 16 s,only 80 ml contrastCourtesy of Thorax Center Rotterdam,the NetherlandsAdvantage and Disadvantage of CT Advantage：Tomographical image High density resolution Contrast

22、 enhancement have wide applications Disadvantage：Expensive X-ray Magnetic Resonance Imaging (MRI）Imaging method using a strong magnetic field and gradient field to localize burst of radiofrequency signals coming from a system of spins consisting of reorienting hydrogen(H)nuclei(protons)after they ha

23、ve been disturbed by radiofrequency pulses.Recent progress in the art of MRI Magnetic resonance imaging(MRI)is a noninvasive method of mapping the internal structure of the body which completely avoids the use of ionizing radiation and appears to be without hazard.MRI has now rapidly progressed from

24、 being a technique with great potential to one which has become the primary,and often the only,diagnostic method required for many clinical problems.Recent progress in the art of MRI The phenomenon of MR was described independently but almost simultaneously by Bloch and Purcell in 1946 and for their

25、 discovery they were jointly awarded the Nobel Prize for Physics in 1952.Because the use of MR for imaging required a method for spatial localization,Lauterbur and Mansfield were jointly awarded the Nobel Prize for medicine in 2003.MR has the ability to display structures in a transverse or axial fa

26、shion,similarly to CT.However,MR has the additional advantage of being able to produce images in virtually any orientation.The common display orientations used are sagittal and coronal as well as axial planes.In general,during an MR examination three forms of MR image can be produced:T1 weighted ima

27、ge(T1WI),T2 weighted image(T2WI),and proton density weighted image(PDWI).Tissues or substances with short T1 relaxation times(short T1)have high signal intensity and appear bright on T1WI,whereas tissues or substances with long T1 relaxation times(long T1)have low signal intensity and appear black o

28、n T1WI.Tissues or substances with short T2 relaxation times(short T2)have low signal intensity and appear black on T2WI,whereas tissues or substances with long T2 relaxation times(long T2)have high signal intensity and appear bright on T2WI.Water appears black on T1WI and bright on T2WI because it h

29、as long T1 and long T2 relaxation times.Fat appears bright on T1WI and medium signal intensity on T2WI because it has short T1 relaxation times and medium T2 relaxation times.Muscle appears medium signal intensity on both T1WI and T2WI because it has medium T1 and medium T2 relaxation times.Cortical

30、 bones,calcium,and lung tissues appear low signal intensity(black)on PDWI as well as T1WI and T2WI because they have very litter hydrogen(proton).Imaging pulse sequence spin echo(SE)sequence inversion recovery(IR)sequence a variety of acronymic gradient echo(GR or GRE)sequence techniques(e.g.STIR,FI

31、SP,and FLASH,etc.)The fastest sequence of MRI used today is echo planar imaging(EPI)MRI characteristics膝关节外伤，胫骨骨折膝关节外伤，胫骨骨折Application of MRI Enhancement tumor blood-brain barrier more sensitive MRAMRI contrast medium Gd-DTPA paramagnetic contrast medium AMI-25 superparamagnetic contrast mediumMRI E

32、quipment Low field MR，open system MRRecent progress in MRI unit Polarization of magnetic field Special MR Unit Faster and stronger magnetic resonance gradients RF coil RF CoilsAdvanced Imaging Techniques Whole body MR screening It is an ideal modality for the purposes of healthcare screening that ha

33、s both high sensitivity and specificity with out radiation hazard.The true benefit of whole body MR imaging is in the variety of disease found.Its value is in its reliability and accuracyPatient with PlasmocytomaTSE T1+2w,PAT 2Schlemmer,Claussen et al.University Tuebingen(Germany)SH Changhai Hospita

34、l全身成像多发转移3D ToFTR/TE 35/3.6 ms,192x512,SL 0.8 mm,108 partitionsTA:6:44 minHigh-Resolution ToF at 3TToF MRA of the HandHigh-resolution 3D ToF with water excitationNo contrast agent3D FLASH fat satSL 1 mm,256x512,215 partitionsTR/TE 33/4.9 ms,TA:9:00 min 高分辨乳腺成像SH Changhai Hospital乳腺动态扫描SH Changhai Ho

35、spital2D PACE 自由呼吸腹部成像自由呼吸腹部成像T2W TSE Matrix 3842D PACE T2W TSE Matrix 3842D PACE with fatsat 北京阜外医院北京阜外医院Other MRI Techniques Fat suppression MRC（Cinema）MRA MRCP,MRU Functional MRI（fMRI）MRS DWI PWISubsecond 3D MRA of Aortic Aneurysm High Resolution MR Angiographyhigh resolution 512 matrix in 18 sec

36、 aquisition timeSubsecond 3D MRA of Aortic Arch StenosisSubsecond MRA of Aortic Dissection3D TrueFISP Coronary MRA Flexibility:the choice is yoursbreathhold in 20 secDark Blood Coronary MRA with 3D TSE&NavigatorsSchlemmer,Claussen,Univ.Hospital Tuebingen,GermanyMRCP post cholecystectomyin 1.8 second

37、sMultiple liver cystsUreter cancerMRU BH TA:4secs Fl2d t1w fs with contrast VIBE SL 2mm TA:18 secs with contrast 河北省肿瘤医院河北省肿瘤医院3D TSE IACSL 0.5mmMIP北京阜外医院北京阜外医院哈尔滨医科大学第一附属医院哈尔滨医科大学第一附属医院Increased BOLD Effects at 3.0T BOLD contrast is in the range of 3.0T=5 to 10%1.5T=1 to 2%3.0T1.5TIncreased BOLD Ef

38、fectsRRRWhite matter tractacd手动功能手动功能区区肿瘤肿瘤天津环湖医院DWI/PWI-based“Risk Maps”T2ADCMTTCBFCBVHWIInitial Low b+ADC01Courtesy O.Wu,G.Sorensen,MGHFollow-up T2(2 Months)CombinedDWI+HWICourtesy of Dr.R.White,Cleveland Clinic,Cleveland,USASiemens was the first to offer these as a productInfarct Evaluation:Cine&

39、Late EnhancementClinical Protocols for Infarct EvaluationCourtesy of Northwestern University Chicago,USA TrueFISP cine Late Enhancement Gadolinium Contrast Enhancement in Myocardial InfarctionEx-vivo comparison of TTC and Gd-enhanced MRI in infarcted myocardiumCourtesy of Dr.R.Judd,Northwestern Univ

40、ersity,Chicago,USATTCMRIOther advanced applicationT2-Mapping with Tools for T2 Time calculationT2 mapT2 map早期OA，T2 map显示外侧髌股关节面软骨T2时间变长（绿色）Metastasis上海复旦大学附属中山医院上海复旦大学附属中山医院波普分析SH Changhai Hospital Contraindication pacemaker aneurysm clips intraocular metallic foreign bodies serious patientAdvantage

41、 and Disadvantage of MRI Advantage：Multiple tomographical image More information from imaging High soft tissue resolution Contrast enhancement have wide applications Disadvantage：Expensive Complication More contraindication Molecular Imaging Though evolving continuously,the field of molecular imagin

42、g is expected to bring radiology into the forefront of disease diagnosis and therapy design through advances in three modalities:radionuclide,MR,and optical imaging.How to Make a Imaging DiagnosisImaging Analysis and Diagnosis Clinical history Technique protocol Visualize regularly Differentiate nor

43、mal or abnormal Lesion analysisposition and spread,number,shape,edge,signal or density,adjacent organs and tissue,functionImaging Analysis and Diagnosis Combine clinical material:different diseases with same imaging appearance,same diseases with different imaging appearance Differentiate benign or malignant Diagnosis：confirmation,negative,possibility Position(where)Suggestion