Is there a DICOM tag that determines whether it is a human radiograph (HWS, LWS, ...) or a technical radiograph (specimen) DICOM file / DICOM image.
EDIT
In between I checked this link
https://dicom.innolitics.com/ciods/hemodynamic/patient/00102202/00080100
I don't found any DICOM tag that help me out.
Although there are such keys:
(0028,0300) Quality Control Image - Indicates whether or not this image is a quality control or phantom image. NEMA
(0050,0004) Calibration Image - Indicates whether a reference object (phantom) of known size is present in the image and was used for calibration. NEMA
However, I would suggest you not to rely on them too much, as they are not mandatory. Moreover, you cannot know whether proper examination protocol was set before taking the image.
Related
I'm look for a DICOM image reconstruction tag. Is there any tag to recognize a DICOM Image is result of a reconstruction?
First try searching for "MPR" (multiplanare Rekonstruktion) but just for Siemens?
(0008,0008);Image Type;DERIVED\PRIMARY\AXIAL\CT_SOM5 MPR
(0008,103e);Series Description;Abdomen nativ 3.0 MPR kor
Image Type (0008, 0008) is the field you are searching for. Unfortunately, you will run into three issues:
Not all vendors stick to the defined terms for this attribute, some treat them as free text. So does Siemens - "CT_SOM5 MPR" is not a defined term for this attribute.
it depends on the type of object (SOP Class UID) which defined terms apply and from which component of Image Type they can be obtained.
DERIVED\SECONDARY\MPR (MPR is value 3 for MR objects)
DERIVED\SECONDARY\ANGIO\RESAMPLED (RESAMPLED is value 4 for Enhanced IODs)
There are several reconstruction techniques, MPR is just one of them
There is an attribute Volume Based Calculation Technique (0008, 9207) from which this could be safely determined, but so far I have never seen it included in practical datasets. Plus, it is not allowed for all IODs
Long story short: Using Image Type and sticking to the rules and defined terms applying to this attribute would be DICOM conformant and correct, but fail in some practical cases. I do not see any other generic approach. To include more practical cases, you will need to implement vendor-specific heuristics.
When I receive scout images, where I can find the x-tube angle information from the DICOM header? Basically I need to know the scout was taken when x-tube is at the top or it is at the 90 degree or any other degree.
The precise answer to your question depends on the type (SOP Class UID) of DICOM object that your question refers to. AFAIK, the tube position is never encoded in DICOM headers, however, what you probably want to know is the orientation of the image plane in the patient coordinate system.
Most commonly (for CT/MR) this is encoded in the attribute (0020,0037) Image Orientation Patient which contains 6 floating point numbers describing the x,y,z components of the row and column vector of the image.
Please note that this orientation refers to the other slices of the same scan, there is no absolute reference coordinate system.
If this attribute is missing, (0020,0020) Patient Orientation may give you a hint, but not as precisely as the vectors.
We are writing an importer for dicom files.
How does one generally deceide if a series of images forms a 3D-Volume or is just a series of 2D images?
Is there a universal way to decide this for most vendors? I looked a the DICOM tags and could no find an apparent solution.
The DICOM standard defines UIDs for describing the hierarchy. These are from top to bottom:
Study UID - Identifier of the study or scanning session.
Series UID - The same within a series acquired in one scan.
Image UID - Should be unique for any image.
A DICOM image saved by a standard-conforming implementation should have all these IDs. If multiple images have the same SeriesUID, they are a volume (or time-series) as defined in the standard. Some software of course is not standard-conforming and you'll have to look at other things like timestamps and patient position, but it is usually best to start by following the standard.
For ordering the series after identifying it, GDCM (as malat suggested) or dcmtkdicom are pretty well-established libraries.
In MR, you'll want to look for:
MR Acquisition Type (0018,0023). It has two enumerated values:
2D = frequency x phase
3D = frequency x phase x phase
I'm not as sure about CT.
Most of the time, malat's answer is what you'll want to do (i.e. organize the slices by position and orientation and treat them in a 3D fashion through multi-planar reconstruction).
I think what you are searching for is the algorithm to organise DICOM dataset using Image Position (Patient) and Image Orientation (Patient).
A typical implementation can be found in GDCM
Please note that my answer may be totally unrelated to your specific DICOM instances, but since you did not specified which SOP Class UID you were dealing with, I simply assumed you were dealing with old CT or MR Image Storage
Patient Position (0018, 5100) is a type 1 required attribute for both the CT and MR modalities. This attribute is VERY IMPORTANT for accurately interpreting the patient's orientation.
Projection radiograph typically will have Patient Orientation (0020, 0020) attribute and cross-sectional image should have Image Position (0020, 0032) and Image Orientation (0020, 0037) attributes as they are type 1 required element of Image Plane module (see PS 3.3 section C.7.6.2.1.1).
However, localizer or scout image included with CT study is not really a cross-sectional image but a projection image and may contain Image Position and Image Orientation attributes. So is the case of MR study where one or more sagittal or coronal images are usually captured from which axial images are prescribed. In this case different logic is needed to identify the localizer image. For example, CT localizer may use the string "LOCALIZER" for value 3 of "Image Type" attributes.
If someone haven't found the answer, I looked through the tags in RadiAnt DICOM viewer where I compared different files and the Scan Options (0018, 0022) tag I think which contains the information. If the tag exists (because on some it was not there) and the value is equal to HELICAL MODE or HELIX then a 3D image can be constructed from that.
I am really confuse over the draw overlay
on MRI Image means its part is similar to Structure Report(SR) Processing or not
I am trying to read the MRI File in such way that from Contrast Agent. Also after so much searching on Google finally get some information such as
"The data is extracted by injecting a contrast agent into a patient’s vein,then taking sequential snapshots of a volume of interest as the contrast agent diffuses through that area"
but i am totally new for this to help out can you help me for
1. Give me specific link for these topic
2. How to read the Contrast Agent value from MRI Dicom File.
3. Also how to show a shaded region where the Cancer is detected or
some kind of marker on that location where the pixel intensity of
dicom file is higher.
Well, MRI scan is just a stack of grayscale images, pretty much as CT is, except that intensity units are of course different. So, just read it as any other dicom image, and look pixels values for intensities, or perform segmentation.
Cancer tumor regions and other features are stored in a separate dicom object, called RT structure set (it is produced usually by radiotherapy planning system or some contouring software).
I got a CD from the hospital that is a head CD scan.
I am completely new to medical imaging. What I would like to do perform a volume rendering of the CT scan.
It is in DICOMDIR format. How and where would I start?
From messing about with various tools I get the feeling that I need to extract each series into DICOM format. Is this correct and if so how would I do it?
Unless you were given the volume data your rendering will be disappointing at best. Many institutions still acquire head CT's in separate "step-slices", and not as volumes so here you will have significant 'stepping' artifact.
Even if it was acquired with volume data, unless they transferred all the data to your CD, you will still be stuck with only the processed 'slab' or 'slice' images.
The best way to do a volume rendering is to actually have the volume data. "Slice image" data has most of the information dumbed down and removed. You are just getting 20 or 30 images in 256 x 256 x (8 or 16 bit greyscale) array data.
If you have a mac try OsiriX - it's free, open source and will do everything you need and more. If you don't, and this is a one time thing, you could always sign up for a free demo of a commercial grade DICOM viewer. Medical image viewing software is insanely expensive and would be impossible to sell without demos. Just claim to be working for a clinician and you'll have no problem getting working software.
I believe ImageJ will open any of the files in the DICOMDIR for you. I'm not entirely sure it can open the entire study from the DICOMDIR, but I'm fairly certain it will handle any individual files you need to open. It should also offer the option to export the images to various other formats. If you need more info, feel free to post a comment.
You can also try MevisLab (http://www.mevislab.de/) it is free but a bit more complex to use and maybe it requires two steps to get the rendering of your dicom images.
Most probably you have to use one of the widgets they provide to convert the image and then to load the converted image and render it.
I have done with ImageJ but ImageJ not support compress dicom files at that time you have create your own logic to read compress dicom file.
Fiji and VolumeJ are also Good Option for Volume Rendering
Try Real3d VolViCon which is an advanced application for reconstruction of computed tomography (CT), magnetic resonance (MR), ultrasound, and x-rays images. It gives features for exporting 3D surfaces or volume as triangular mesh files for creating physical models using 3D printing technologies. It also provides high-quality visualization, linear and angular measurement tools, and various type of markups. It takes a single raw volume file or a sequence of 2D (i.e., DICOM) files and reconstructs 3D volume (voxels) and mesh (surfaces) models.