DICOM Image Metadata Parsing Module
Overview
The DICOM Image Metadata Parsing module is a utility designed for extracting, parsing, and handling metadata from DICOM (Digital Imaging and Communications in Medicine) files. The module offers various functions to retrieve and transform DICOM tag values into usable formats. It is capable of handling different value representations (VRs) such as strings, integers, dates, and other complex structures commonly found in medical imaging datasets.
This module allows developers to parse DICOM tags and convert them into human-readable formats or machine-usable data, supporting various data types like strings, numbers, dates, and arrays.
API Reference
parseTag
This function retrieves and processes a specific DICOM tag based on its VR. It starts by checking if the VR is provided in the dataset; if not, it retrieves the VR using a DICOM dictionary. The function can process various VR types like strings, integers, floating points, dates, and more.
The function performs type-specific transformations to convert the raw data into usable values, such as:
- Strings (e.g.,
SH,LO,ST): Returns the string value after checking for valid ASCII characters. - Integers (e.g.,
IS,US): Converts the string of digits into an integer, handling multiple values if necessary. - Dates (e.g.,
DA,DT,TM): Parses date and time strings into standard JavaScript Date objects. - Character Sets (e.g.,
PN,SH): Handles special character sets and converts them to readable strings. - Binary Data (e.g.,
OB,OW): Returns raw binary data or tries to convert it into a readable format if possible.
The function can also handle complex data structures like sequences (SQ), which are recursively parsed and returned as nested objects. The pipeline is readFile->parseFile->parseDataSet-> parseTag to extract and organize metadata in a readable format from a DICOM dataset and add them to the metadata object (see Parsing ).
Syntax
parseTag<T>(dataSet: DataSet, propertyName: string, element: Element): T
Parameters
| Parameter | Type | Description |
|---|---|---|
dataSet | DataSet | The parsed dataset object from dicom parser. |
propertyName | string | The tag name |
element | Element | The parsed dataset element |
Returns
T- The parsed and formatted DICOM tag value. The return type is generic and depends on the VR type of the tag being parsed (e.g., string, number, date, etc.).
getTagValue
Extracts the value of a specific DICOM tag from the dataset according to its Value Representation
Syntax
getTagValue(dataSet: DataSet, tag: string): any
Parameters
| Parameter | Type | Description |
|---|---|---|
dataSet | DataSet | The parsed dataset object from dicom parser. |
tag | string | The tag name |
Returns
any- The value associated with the tag.
Internal Functions
getDICOMTag
Retrieves the DICOM tag information for a given tag code.
Syntax
getDICOMTag(code: string): object
Parameters
| Parameter | Type | Description |
|---|---|---|
code | string | The DICOM tag name. |
Returns
object - The DICOM tag information, including the tag name and VR.
isStringVr
Checks if the value representation (VR) is a string type.
Syntax
isStringVr(vr: string): boolean
Parameters
| Parameter | Type | Description |
|---|---|---|
vr | string | The value representation (VR) |
Returns
boolean - true if the VR is a string type, otherwise false.
parseDateTag
Parses a DICOM date tag (DA) into a standardized date format.
Syntax
parseDateTag(tagValue: string): string
Parameters
| Parameter | Type | Description |
|---|---|---|
tagValue | string | The DICOM date value in YYYYMMDD format |
Returns
string - The parsed date in a readable format (YYYY-MM-DD).
parseTimeTag
Parses a DICOM time tag (TM) into a standardized time format.
Syntax
parseTimeTag(tagValue: string): string
Parameters
| Parameter | Type | Description |
|---|---|---|
tagValue | string | The DICOM date value in HHMMSS.FFFFFF format |
Returns
string - The parsed time in a readable format (HH:mm:ss).
parseDateTimeTag
Parses a DICOM date-time tag (DT) into a standardized date-time format.
Syntax
parseDateTimeTag(tagValue: string): string
Parameters
| Parameter | Type | Description |
|---|---|---|
tagValue | string | The DICOM date value in YYYYMMDDHHMMSS.FFFFFF format |
Returns
string - The parsed date-time in a readable format (YYYY-MM-DD HH:mm:ss).
formatDate
Formats a given date into a standardized string format.
Syntax
formatDate(date: Date): string
Parameters
| Parameter | Type | Description |
|---|---|---|
date | Date | The Date object to format |
Returns
string - The formatted date in YYYY-MM-DD format.
formatDateTime
Formats a given date-time into a standardized string format.
Syntax
formatDate(date: Date): string
Parameters
| Parameter | Type | Description |
|---|---|---|
date | Date | The Date object to format |
Returns
string - The formatted date-time in YYYY-MM-DD HH:mm:ss format.
isValidDate
Checks if a given date is valid.
Syntax
isValidDate(d: any): boolean
Parameters
| Parameter | Type | Description |
|---|---|---|
date | any | The date to check |
Returns
string - true if the date is valid, otherwise false.
parsePatientNameTag
Parses a DICOM patient name tag (PN) into a structured name format.
Syntax
parsePatientNameTag(tagValue: string): string
Parameters
| Parameter | Type | Description |
|---|---|---|
tagValue | string | The DICOM patient name in LastName^FirstName^MiddleName format |
Returns
string - The parsed patient name, formatted as LastName, FirstName MiddleName.
parseAgeTag
Parses a DICOM age tag (AS) into a standardized age format.
Syntax
parseAgeTag(tagValue: string): string
Parameters
| Parameter | Type | Description |
|---|---|---|
tagValue | string | The DICOM age value in nnnD, nnnW, nnnM, or nnnY format |
Returns
string - The parsed age in a human-readable format (e.g., "25 years", "6 months").
parseDICOMFileIDTag
Parses a DICOM file ID tag (CS) into a standardized ID format.
Syntax
parseDICOMFileIDTag(tagValue: string): string
Parameters
| Parameter | Type | Description |
|---|---|---|
tagValue | string | The DICOM file ID value |
Returns
string - The parsed DICOM file ID.
