BoneDense&Informatics
BMD Test Results
BMD=g/cm2 of bone mineral ***Z-scores normalize a patient's BMD by assessing the amount of bone loss compared to the expected loss for age-matched peers*** ***T-scores indicate the amount of bone loss, by quantifying the difference between a patient's BMD at his/her current age, and the peak bone mass for young normals ***
RAID Level 0-Striping
Data spread over numerous drives No fault tolerance If one drive fails, data is lost Not good for critical applications
Fractures associated with Osteoporosis
Fragility Fractures minimal trauma standing height or less spontaneous
T-scores are used to decide whether a patient has reduced BMD consistent with osteoporosis and osteopenia.
T-score Classification T> -1.0 SD Normal -1.0 SD <T< -2.5 SD Osteopenic T < -2.5 SD Osteoporotic **For every SD of decline, fracture risk increases 2-3x!**
Results T & Z score
T-score between +1 and −1 is considered normal or healthy. A T-score between −1 and −2.5 indicates that you have low bone mass, although not low enough to be diagnosed with osteoporosis. A T-score of −2.5 or lower indicates that you have osteoporosis. The greater the negative number, the more severe the osteoporosis.
Z- score
age matched
Normals
**Normal Bone density is within 1 SD (+1 or −1) of the young adult mean. ***Low bone mass Bone density is between 1 and 2.5 SD below the young adult mean (−1 to −2.5 SD). ***Osteoporosis Bone density is 2.5 SD or more below the young adult mean (−2.5 SD or lower). ****Severe (established) osteoporosis Bone density is more than 2.5 SD below the young adult mean, and there have been one or more osteoporotic fractures.
History
**Radiography (plain films) Demineralization only becomes apparent after 40% loss of BMD **Single Photon Absorptiometry (SPA) used a single energy photon beam that passed through bone and soft tissue. **Dual photon Absorptiometry (DPA) used an isotope that emitted photon energy at two distinct photoelectric peaks. **Dual Energy X-Ray (DXA) An x-ray tube replaced the radioactive isotope source of photon energy.
DEXA Scanning Principles
*2 different photon energies are used to seporater the x-ray attenuating effects of soft tissue and bone. *Filters (Lunar Corp., Norland Medical Systems). *Synchronously switching between two kilivoltage peaks (Hologic, Inc.).
Standards = HL7-Health Level Seven-standard
*for exchange of patient demographic information among hospital information systems, non-image data *HL7 data identifies patients, processes orders, stores reports and generates billing but does not manage DICOM (image) data
Standards= MQSA-Mammography Quality Standards Act
1992 Congress established national standards for mammography All facilities performing mammography must be accredited, certified, and inspected Accreditation must be renewed every 3 years
Risk for Osteoporosis in Men
2 million American men have Osteoporosis (20%). 3 million American men have low bone mass. Suffer 33% of all hip fractures.
An Epidemic of Fractures
28 million Americans currently suffer from osteoporosis or have low bone mass [1] Over the next 20 years, this number could rise to 40 million [1] Low bone mass causes 1.5 million fractures a year [1] 700,000 vertebral fractures [1] 300,000 hip fractures a year [1] 20% mortality rate [2] 50% require some form of assisted living [2]
T-score
peak bone mass
Osteoporosis
A disease characterized by low bone mineral density with the presence of fracture. Primary Type I - bone resorption exceeds bone formation, due to estrogen deprivation (post menopausal). Type II - a decreased ability to build bone due to age. Secondary Skeletal disorders resulting in bone turnover(genetic, endocrine, hematologic, malignancy).
Osteopenia
A disease characterized by low bone mineral density without the presence of fracture. *Left untreated can lead to osteoporosis
Peripheral DEXA (pDEXA)
A small, portable device that works similarly to DEXA but is used to examine bone density in peripheral bones, such as the oscalsis, radious and ulna(best for single event measurment).
Focus on PACS
Acquisition Network Display Archiving
Osteoporosis: A Multifactorial Disease
Age, gender, race , body size, Lifestyle factors, Menospause,family history , drug treatments, and other illnesses
RAID Level 1-Mirroring
All data is duplicated One drive is exact replica of other Most fault tolerant Least efficient storage Uses half of storage capacity
Industry Momentum
Approved drugs are now available for prevention and treatment of osteoporosis At least 45 companies are currently developing additional therapies Increased attention to women's health Increased focus on "graying of America" Increased focus on disease prevention
Women Are Most Susceptible
Approximately 13 to 18% of postmenopausal Caucasian Americans (4 to 6 million) have osteoporosis Another 30 to 50% (13 to 17 million) have low bone density Almost one out of two will suffer an osteoporotic fracture (for men, it is one in five) Risk of a hip fracture alone exceeds the combined risk of developing breast, uterine or ovarian cancer
Vendor Neutral Archive (VNA)
Archive where images are stored in a standard format with a standard interface (may include documents and variety of image types, i.e. DICOM, jpeg, etc.) Can be accessed in a vendor-neutral manner by other systems Typically supports a healthcare enterprise as opposed to one department (i.e. radiology, cardiology, dental, etc.)
PACS Image Tools
BASIC=Pan,Zoom,Magnify,Measure,Window/Level,Invert ADVANCED= Stack,Tile,Series select,Multiplanar,3D rendering,Hanging protocols
DXA (DEXA): The Gold Standard
Detects early bone loss and monitors therapeutic effectiveness. Measures axial skeletal sites where early bone loss occurs High precision (<1.0%) Low patient dose High-resolution imaging (images are used for positioning purposes NOT diagnostic quality). Most common problems are operator related.
DICOM stands for
Digital Imaging and Communications
Pharmacologic Options for Osteoporosis
Estrogen Replacement Therapy (ERT): Approved for prevention and treatment of osteoporosis. Hormone Replacement Therapy (HRT): To eliminate the risk of increased chance of developing cancer of the uterine lining. Alendronate [Fosomax, Merck & Co.]: Fosomax most widely used for osteoporosis Approved by the FDA for prevention and treatment of osteoporosis. Calcitonin [Miacalcin, Novartis]: FDA-approved for treatment of osteoporosis. Raloxifene [Evista, Eli Lilly & Co.]: FDA-approved for the prevention of osteoporosis. Investigational Treatments: New forms of bisphosphonates, selective estrogen receptor modulators, sodium fluoride, parathyroid hormone and vitamin D metabolites.
RAID Level 5-Striping with Parity
Fault tolerant Requires at least 3 drives One drive failure allows for continued operation and recovery of data Two drive failure, data is lost
Peak Bone Mass: Determinants PEAK BONE MASS (about 30 years old)
GENETIC INFLUENCE, Hormonal Factors,Nutritional Factors,Exercise & Environmental Factors
What are the risk factors contributing to osteoporosis?
Gender (Female) Age (post-menopausal) Race (Caucasian, Asian, Hispanic) Body Weight (thin, small-boned)
Women Are Most Susceptible
Generally at greater risk of developing osteoporosis than men Tend to build less bone than men when they are young Experience a rapid skeletal bone loss due to the decrease in estrogen production, following the menopause Seventy-five percent, aged 45-75, have never even discussed osteoporosis with their physicians
What Makes A Workstation "Diagnostic"
Good viewing conditions, environment, lighting High enough spatial resolution High quality monitors Good quality assurance Most facilities will follow diagnostic workstation guidelines recommended by the ACR
Two Types of Bone
Cortical bone: makes up 80% of the skeletal mass, but accounts for only a small proportion of the total bone turnover (functions mainly mechanical and protection). Trabecular (calcaneus) bone: represents 20% of the skeletal mass, but due to its large surface-to-mass ratio, a far greater percentage (80%) of bone turnover (function mainly metabolic).
RAID
Redundant Array of Independent Disks Uses multiple hard drives to share or replicate data, implemented in different levels with varying degree of fault tolerance
Bone Mineral Density (BMD)
Refers to amount of mineral contained within a certain amount of bone: Helps determine bone strength and fracture risk Provides clinicians with a practical way to identify individuals with osteoporosis and those at risk of developing the disease Useful in monitoring therapy efficacy
Goals
Seamless flow of information from order through report (our "product") Accurate and complete information for patient records and for end users (MDs) Enhances workflow within the Radiology department Improvement of healthcare and delivery particularly focusing on Radiology
Archiving-Goals
Short/Medium term archive-Fast access for a period of 1 - 5 years. .Magnetic Disks .RAID Long term archives - forever . . or as dictated by the law.(florida = 7 years) .Tape .DVD .Optical Disks-Blue-ray .RAID
BMD Testing Methods
Single x-ray absorptiometry (SXA) uses a small, portable device that works similarly to DEXA, but emits a single x-ray beam. It is used to examine the heel bone or forearm.
IHE-Integrating the Healthcare Enterprise
In order to achieve successful integration of information systems (DICOM and HL7) regardless of vendor, the IHE framework was developed-not a standard yet *IHE-the defined profiles use sets of DICOM and HL7 messages and include specifications on how to map specific attributes between the two standards
Color vs Monochrome
In the past for CR images only a true monochrome (greyscale shades only) monitor was best viewing scenario as a diagnostic workstation New color monitors available that have the ability to calibrate to the necessary dynamic range that monochrome offers, universal monitor Color has been adequate for CT, MRI, US, NM etc. ***GSDF -Greyscale Standard Display Function-DICOM standard, medical grade monitors must meet this standard for diagnostic image interpretation
Dual Energy X-Ray Absorptiometry DEXA)
In this technique, an x-ray tube emits two x-ray beams of dual energy or filters are used that result in two seperate energy beams, which pass through the bone and are picked up by a detector or detectors, as in the case of fan beam technology. A computer is then used to analyze the resulting images and calculate bone density based on the amount of radiation absorbed by the bone.
Networks
Latency- the amount of time it takes a data packet to get from source to destination Bandwidth- the collective amount of data that can be transmitted at one time Image acquisition gateway- network server that receives PACS images from modalities, forwards to temporary and permanent storage
Focus
Standards Acquisition Network Display Archiving Quality Assurance Integration
High Quality Monitors
Monitors should be at least 2Mpixels, but larger (3Mpixels and higher) is better High resolution monitors-5Mpixels are used for mammography.
Display Workstations
Most will be able to do basic functions: Window/Level, Magnify, Zoom, Roam, Flip/Rotate Stack / tile mode for CT, NM, MRI and CR, US, Fluoro High level workstations allow multiplanar reformat (MPR), maximum intensity projection (MIP)
Medial Imaging Informatics
Multidisciplinary field that intersects with the biological sciences, health services, information sciences, medical physics, and engineering Touches every aspect of the imaging chain Image acquisition Image processing and analysis Images distribution Image storage and retrieval Image visualization Image interpretation and reporting
Advantages of Tube over DPA
No source decay Greater source intensity(can increase keV) A smaller focal spot(better pinpoint) Increased beam collimation Less dose Better image resolution Faster scan times Improved precision
Economic Impact
Osteoporotic fractures cost the U.S. healthcare system $14 billion in 1995 Osteoporosis is the direct cause of: 2.5 million physician visits 432,000 annual hospital admissions 180,000 nursing home admissions The number of hip fractures and associated costs could more than triple by the year 2040
DICOM Services
Store, storage comittiment, Query/Retrieve, Modality worklist, Modality performed procedure step-MPPS-(information specific to the study such as image acquisition times, exam start and end time, dose delivered, etc. sent to the PACS in report form), Print, and Offline media
Bone: A Dynamic Tissue
Supports muscles, protects vital organs and stores calcium Built and stored efficiently until about the age of 30 Affected by diet and exercise Breaks down faster than formation of new bone as we get older Osteoporosis results in reduced bone mass and altered structure
DEXA Patient Preparation
Provide patient with explanation of exam Remove any metallic objects (some facilities require changing into a gown). No exams within 7 days with radiopharmaceuticals or contrast media.(No barium) No calcium supplements 2 hours prior to exam
Behavior Modification
Prevention of falls. Weight bearing exercise.
Females have a _____ risk of developing osteoporosis.
greater
DXA / DEXA Imaging procedure
The DEXA machine sends a thin, invisible beam of low dose x-rays through the bones via two energy streams. One energy peak is absorbed mainly by soft tissue and the other by bone. The soft tissue amount can be subtracted from the total, and what remains is a patient's bone mineral density. ***90% of all DEXA scans are preformed on the spine and proximal femur (hip).Forearm is used as an alternate site. **
Bone Densitometry
The art and science of measuring bone mineral content and density.
Two different energies used to better differentiate:
between soft tissue and bone
This patient has osteoporosis.
This patient (indicated by X) has a bone density that is 1 SD below age-matched normals and 2.5 below the mean bone density of young normals. Based on the World Health Organization's definition, this patient has osteoporosis.
Purpose of Bone Density Exams
To aid in the diagnosis of diseases associated with low bone density (Osteoporosis). Predict risk of fractures. Asses the need for pharmacological interventions. Monitor the effects of drug therapy
Bone Loss in Women After Menopause
Trabecular bone
A vendor who supplies DICOM services must comply and be compatible with:
True
Osteoporosis: A Huge Unmet Need
Undiagnosed, Untreated( 77%) Diagnosed, Treated(9%) Diagnosed, Untreated (14%)
National Osteoporosis Foundation Guidelines of who should have a BMD test:
Women 65 and older, regardless of other risk factors Postmenopausal women with one or more risk factors All postmenopausal women who have had a fracture
BMD scan results given in:
Z and T score
Women experience a rapid skeletal degrade after menopause due to:
less production of estrogen
Thinning of bones known as:
osteopenia
Bandwidth is defined as:
the collective amount of data that can be transmitted at once
BMD (bone mineral density) refers to:
the mineral contained within the bone
Measurement of hip BMD has shown to be the most reliable way of evaluating:
the risk of fracture
Standards= DICOM-Digital Imaging and Communications in Medicine-standard for communications among imaging equipment
DICOM is a transmission protocol that creates, stores, prints, and forwards image data to and from the imaging modalities and PACS (jpeg) Promotes communication of digital image data regardless of device vendor Certain DICOM standards must be met for equipment to be "DICOM" compatible, minimum of store, modality worklist, query/retrieve, print
Standards= ACR-American College of Radiology
Defines the practice guidelines and technical standards used in Radiology Technical standard for Electronic Practice of Medical Imaging Practice Guideline for Determinants of Image Quality in Digital Mammography-MQSA
Acquisition
Images are two dimensional arrays of pixels Each pixel represents a gray scale or color based on a number Each pixel is represented by one or two bytes of data Size of the image has an impact on the networking, archiving and display
Compression
Images can be compressed to store and transfer on a network. Lossless= compression allows the image to be restored to its original fidelity with no loss of data. Lossy= compression does not allow the image to be restored to its original fidelity and some data will be lost. Lossy compression may result in images that are perfectly diagnostic BUT may result in images that have artifacts, contouring, and large pixels Digital mammo can only be stored using Lossless compression per MQSA
CRT vs LCD Monitors
LCD monitors are lighter weight, use less space, and last longer with less degradation over time. LCD monitors are still very expensive. A pair of monochrome 3MPixel LCD monitors cost about $11,000 with the video cards to drive them. New configurations offer one widescreen, 4 or 6MPixel monitor LCD medical grade monitors usually have calibration built in. LCD medical grade monitors are usually brighter than CRTs.
CRT vs. LCD monitors:
LCD monitors are lightweight, use less space, and..
BMD Testing Methods
Quantitative computed tomography (QCT), uses a standard CT scanner—fitted with special equipment and software to measure bone mass—to deliver x-rays to the spine at many different angles.
BMD Testing methods
Quantitative ultrasound (QUS), the only technique for measuring bone density that does not use x-rays, works by transmitting high-frequency sound waves through the heel bone to a signal receiver.
