Computational Medical Imaging Analysis Chapter 7: Biomedical Applications

Transcription

1 Computational Medical Imaging Analysis Chapter 7: Biomedical Applications Jun Zhang Laboratory for Computational Medical Imaging & Data Analysis Department of Computer Science University of Kentucky Lexington, KY Chapter 7: CS689 1

2 7.1a: Neuronal Microanatomy and Function Rapid growth of 3D visualization of microscopic structures happens with the advent of Light and electron microscopy (classical) Confocal microscopy Atomic force microscopy Tunneling microscopy Chapter 7: CS689 2

3 7.1b: Light and Electron Microscopy Light microscopy images digitized directly from the microscope can provide a 3D volume image by incrementally adjusting the focal plane It is usually followed by image processing to deconvolve the image to remove blurred, out-offocus structures Electron microscopy can generate multiple planes by controlling the depth of focus Further processing is necessary for selective focal plane reconstruction Chapter 7: CS689 3

4 7.1b*: Light Microscopes Chapter 7: CS689 4

5 7.1b**: Electron Microscope ($69,000) Chapter 7: CS689 5

6 7.1c: Confocal Microscopy Confocal microscopy uses incoherent light or laser with precise optical control to selectively image specific parallel sections within the microscopic structure Multiple image planes can be selected, providing direct volume image acquisition without the need of signal from structures outside of the plane of interest These images are often acquired using specific fluorescent dyes to selectively image a particular component of the structure under study Chapter 7: CS689 6

7 7.1c*: Confocal Microscope Chapter 7: CS689 7

8 7.1c**: Confocal Microscopy Images Chapter 7: CS689 8

9 7.1c**: Confocal Microscopy Images Chapter 7: CS689 9

10 7.1d: Neuron Visualization The morphology and function of neurons from selected ganglia in the mammalian peripheral autonomic nervous system can be visualized Information about a neuron s shape and dimensions is needed to integrate and localize multiple synaptic inputs The number and location of selective neurotransmitter receptor sites provides valuable information about the potential response of a neuron to a specific transmitter Such visualization applications are termed as spatial physiology in which the function of microstructures are studies Chapter 7: CS689 10

11 7.1d*: Neuron Illustration Chapter 7: CS689 11

12 7.1d*: Single Neuron Chapter 7: CS689 12

13 7.1f: Imaging Neuron Architecture Visualization of the architectural relationships between neurons is less well advanced Nerve plexes, where millions of sensory nerve cells are packed into a few cubic millimeters of tissue, offer an opportunity to image a tractable number of cells in situ This difficulty underscores the need for computerassisted techniques to reconstruct neuronal architectures in vivo They may not be visible directly from the images, but they can be visualized with assisting techniques Chapter 7: CS689 13

14 7.1f*: Rat Neuron Chapter 7: CS689 14

15 7.2a: Corneal Cell Analysis The density and arrangement of corneal cells is an indicator of the general health of the cornea These factors are routinely evaluated to determine suitability for transplant The corneal confocal microscope is a reflected-light scanning aperture microscope fitted for direct contact with a living human cornea The image is a 3D tomographic optical image of the cornea Algorithms are developed for automated measurement of local keratocyte nuclear density in the cornea Chapter 7: CS689 15

16 7.2b: Human Cornea Chapter 7: CS689 16

17 7.2c: Local Keratocyte Density The sectional images represent a section about 15 microns think and at 1 micron intervals through the entire depth of the cornea Both global and local automated density counts in rabbit corneas correlate well to those obtained from conventional histologic evaluation of cornea tissue A decrease in keratocyte density toward the posterior of the cornea was found Chapter 7: CS689 17

18 7.2d: Keratocyte Density Images Left: Corneal confocal image. Right: Nuclei counting Chapter 7: CS689 18

19 7.2e: In Vivo Study of Cornea Density In vivo confocal microscopy images show the presence of densely packed ovoid or elliptical cell bodies, decreasing after birth for a neonate Chapter 7: CS689 19

20 7.2f: Cornea Density of Neonate Laser scanning micrographs of neonatal corneas show decreasing cell density after birth, confirming the in vivo confocal microscopy images Chapter 7: CS689 20

21 7.3a: Trabecular Tissue Analysis in Glaucoma The trabecular tissue of the eye is a ring of spongy, fluid-filled tissue situated at the junction of cornea, iris, and sclera This tissue lies in the only outflow path for aqueous humor, it has long been implicated in the eye disease glaucoma The architecture of the trabecular tissue is so complex that most studies have focused on the arcitecture of the connected fluid space Chapter 7: CS689 21

22 7.3a*: Trabecular Tissue Image Chapter 7: CS689 22

23 7.3b: Connected Fluid Space Analysis The fluid space is generally continuous from the anterior chamber through the trabecular tissue into Schlemm s canal Morphometric analysis (in which small chambers were successively closed) revealed that the interconnection is maintained by very small chambers There are a large number of these narrowings, and they occur at all regions of the tissue Chapter 7: CS689 23

24 7.3c: Connected Fluid Space in Human Trabecular Tissue Before (left) and after (right) morphological opening Chapter 7: CS689 24

25 7.4a: Prostate Microvessels It is common practice to surgically remove cancerous prostates, even though subsequent pathological examination of excised tissues suggest that some surgeries could have been avoided There is a great need for improved non-invasive preoperative techniques that can more accurately measure tumor volume and extent The measures of prostate tumor size and microvessel density are useful indicators of the metastatic potential of tumor Chapter 7: CS689 25

26 7.4a*: Prostate Cancer Chapter 7: CS689 26

27 7.4b: 3D Visualization of Microvessels 3D image analyses show that the ratio of gland volume to vessel length exhibits a twofold increase between benign and malignant tumors The normal tissue shows a characteristic circumferential pattern of the microvessels relative to the glandular tissue In region with adenocarcinoma, the pattern of microvessels is tortuous and radically diffused throughout the glandular volume Chapter 7: CS689 27

28 7.4b**: Tumor & Neovasculature Chapter 7: CS689 28

29 7.4b*: Frog Microvessel Chapter 7: CS689 29

30 7.4c: Measurements of Microvessels Neovasculature exhibits a statistically significantly larger standard deviation of curvature than the normal vessels These measurements can be done with the images Volume of tissue required for the histologic analysis is similar to that obtained via needle biospy 3D image with biospy sample provides a marker for presurgical stage and outcome, improve patient population stratification and eliminate unnecessary surgeries Chapter 7: CS689 30

31 7.4c*: Stages of Prostate Cancer Chapter 7: CS689 31

32 7.5a: Prostate Surgery Planning Radical prostatectomy is the most commonly performed surgical procedure The procedure has significant morbidity Minimizing these negative affects needs a careful balance between completely removal of all cancerous prostate tissue and sparing neural and vascular structures Routine surgical rehearsal using patient specific data could have significant effect on procedural success Chapter 7: CS689 32

33 7.5b: Prostate Cancer Surgery Chapter 7: CS689 33

34 7.5c: Presurgical Rehearsal Presurgical MR volume images of patients scanned with a rectal coil can be segmented to identify and locate the prostate, bladder, and other tissues The segmented images can be constructed into faithful patient-specific models and reviewed by surgeons interactively before the surgery The approach, margins, and critical tradeoffs can be evaluated and determined upon seeing the pathology localized relative to normal anatomy Rendered views of patient-specific models of prostate cancer can be used to accurately assess the tumor size and location relative to sensitive structures Chapter 7: CS689 34

35 7.5d: Prostate Surgical Planning Chapter 7: CS689 35

36 7.6a: Craniofacial Surgery Planning and Evaluation Craniofacial surgery (CFS) involves surgery of the facial and cranial skeleton and soft tissues Preoperative information is most often acquired using X-ray CT scanning for the bony structures, with MRI used for imaging the soft internal tissues 3D visualization facilitates accurate measurement of structures of interest, allowing precise design of surgical procedures It also minimizes the duration of surgery, reducing the risk of postoperative complication and cost Chapter 7: CS689 36

37 7.6b: Craniofacial Surgery (I) Chapter 7: CS689 37

38 7.6c: Craniofacial Surgery (II) Chapter 7: CS689 38

39 7.6d: Craniofacial Surgery Planning Chapter 7: CS689 39

40 7.6e: Craniofacial Reconstruction (I) Chapter 7: CS689 40

41 7.6f: Craniofacial Reconstruction (II) Chapter 7: CS689 41

42 7.7a: Neurosurgery Planning Neurosurgery needs extended knowledge and understanding of intricate relationships between normal anatomy and pathology Multimodality scans are coregistered to help neurosurgeon understand anatomy of interest Specific anatomical objects may be identified and segmented, creating object maps within the digital volumeric data set The diagnostic information is used to determine the margins of pathology, to avoid critical structures, e.g., cerebral vasculature and eloquent cortical tissue Chapter 7: CS689 42

43 7.7a*: Virtual Surgery Planning Chapter 7: CS689 43

44 7.7b: Neurosurgery Planning in Epilepsy Chapter 7: CS689 44

45 7.7c: Neurosurgery Planning in Tumor Resection Chapter 7: CS689 45

46 7.7d: Neurosurgery (I) Chapter 7: CS689 46

47 7.7e: Neurosurgery (II) Chapter 7: CS689 47

48 7.7f: Neurosurgery (III) Chapter 7: CS689 48

49 7.7g: Intraoperative Guidance Interactive computation of line-of-sight oblique planar images for planning neurosurgical approach to large tumor Neurosurgeon will have direct visualization of image planes along the path of surgical approach T1-weighted MRI prior to contrast enhancement (2nd row), T1-wieghted MRI with gadolinium to define tumor size (3 rd row), MR angiogram to localize position of important vessels (4 th row) Chapter 7: CS689 49

50 7.7g*: Neurosurgery (IV) Chapter 7: CS689 50

51 7.8a: Intraoperative Imaging Brain changes position during the neurosurgical intervention, shifting as skull and dura are opened Use of preoperative images for navigation needs to be carefully calibrated against the brain shift Accurate segmented brain models can be provided by optical tracking or global positioning system A heads up display system can allow the surgeon to view 3D models transparently through the surface of the cerebra cortex Chapter 7: CS689 51

52 7.8b: Intraoperative ultrasound images combined with fmri Chapter 7: CS689 52

53 7.9a: Epilepsy Imaging Epilepsy is a prevalent disease (10-20%) caused by abnormal electrical activity in the brain This abnormal electrical signal usually originates at a specific location in the brain, and spreads from a central focus to other regions The location of the abnormal signal focus determines the characteristics of the seizure activity exhibited by the patient Typicals are abnormal motor activity or other unusual sensory behavior Chapter 7: CS689 53

54 7.9b: Abnormal Epilepsy Behaviors Chapter 7: CS689 54

55 7.9c: Epilepsy Brain Signal Activities Chapter 7: CS689 55

56 7.9d: Difficulty to Locate Focus Abnormal electrical activities does not always correspond to any identifiable discrete pathology (e.g., a tumor) Electrical signal sampling with standard electroencephalogram (EEG) recording may give an overall picture of the pattern of electrical activity causing the seizure It will not allow (point out) accurate location to a specific part of the brain Even subdurally implanted electrodes on the cortical surface of the brain do not allow precise identification of regional brain tissue causing the seizure focus Chapter 7: CS689 56

57 7.9e: Monitoring Brain Electrical Activities Chapter 7: CS689 57

58 7.9f: Epilepsy Imaging Using SISCOM A combination of SPECT and MR imaging for improved diagnosis of areas of regional activation in the brain during seizure Subtraction ictal SPECT coregistered to MRI (SISCOM), takes advantages of the transient focal increase in cerebral blood flow in the region of seizure focus It images and statistically identifies the part of the brain involved in the seizure activity SPECT has demonstrated ability to map ictal (during seizure) and interictal (resting, between seizures) blood flow patterns, provides potential for using these in combination to localize the seizure focus Chapter 7: CS689 58

59 7.9g: SISCOM Images A: MRI B: PET C: PET and MRI D: 2 nd MRI from SISCOM E: Difference SPECT F: SISCOM Chapter 7: CS689 59

60 7.9h: Axial Images of Mesial Temporal Lobe Epilepsy (MRI, composite SISCOM) Chapter 7: CS689 60

61 7.9i: Coronal Images of MTLE MRI, composite SISCOM, composite subtraction SPECT, and rainbow color scales for anterior (top) and posterior Temporal (bottom) regions of left MTLE group Chapter 7: CS689 61

62 7.9j: Sagittal Images of left MTLE group MRI, composite SISCOM, composite SPECT, rainbow color Scale for left MTLE group Chapter 7: CS689 62