I have multiple ultrasound images in dicom file. I need to extract information about scale of the image, i.e pixels/cm^2. Is there any dicom tag containing following information? Or should I calculate it somehow. My dicom file looks as following:
Dataset.file_meta -------------------------------
(0002, 0000) File Meta Information Group Length UL: 196
(0002, 0001) File Meta Information Version OB: b'\x00\x01'
(0002, 0002) Media Storage SOP Class UID UI: Ultrasound Multi-frame Image Storage
(0002, 0003) Media Storage SOP Instance UID UI: 1.2.840.113619.2.391.51208.1686298501.4.21
(0002, 0010) Transfer Syntax UID UI: JPEG Baseline (Process 1)
(0002, 0012) Implementation Class UID UI: 1.2.276.0.48.20000.2
(0002, 0013) Implementation Version Name SH: 'TomTecArena v2'
(0002, 0016) Source Application Entity Title AE: 'TTCLIENT'
-------------------------------------------------
(0008, 0008) Image Type CS: ['DERIVED', 'PRIMARY', '', '0001']
(0008, 0016) SOP Class UID UI: Ultrasound Multi-frame Image Storage
(0008, 0018) SOP Instance UID UI: 1.2.840.113619.2.391.51208.1686298501.4.21
(0008, 0020) Study Date DA: '20230609'
(0008, 0021) Series Date DA: '20230609'
(0008, 0023) Content Date DA: '20230609'
(0008, 002a) Acquisition DateTime DT: '20230609081459'
(0008, 0030) Study Time TM: '081459'
(0008, 0031) Series Time TM: '081459'
(0008, 0033) Content Time TM: '081459'
(0008, 0050) Accession Number SH: ''
(0008, 0060) Modality CS: 'US'
(0008, 0070) Manufacturer LO: 'GE Vingmed Ultrasound'
(0008, 0090) Referring Physician's Name PN: ''
(0008, 1090) Manufacturer's Model Name LO: 'Vivid E95'
(0008, 2142) Start Trim IS: '1'
(0008, 2143) Stop Trim IS: '32'
(0008, 2144) Recommended Display Frame Rate IS: '30'
(0010, 0010) Patient's Name PN: '3001'
(0010, 0020) Patient ID LO: '3001'
(0010, 0030) Patient's Birth Date DA: ''
(0010, 0040) Patient's Sex CS: ''
(0012, 0062) Patient Identity Removed CS: 'YES'
(0012, 0063) De-identification Method LO: 'GEVU anonymization'
(0018, 0040) Cine Rate IS: '30'
(0018, 0072) Effective Duration DS: '1.04'
(0018, 1020) Software Versions LO: 'Vivid E95:201.84.0'
(0018, 1063) Frame Time DS: '33.5484'
(0018, 1066) Frame Delay DS: '0.0'
(0018, 1088) Heart Rate IS: '95'
(0018, 1242) Actual Frame Duration IS: '33'
(0018, 1244) Preferred Playback Sequencing US: 0
(0018, 6011) Sequence of Ultrasound Regions 1 item(s) ----
(0018, 6012) Region Spatial Format US: 1
(0018, 6014) Region Data Type US: 1
(0018, 6016) Region Flags UL: 0
(0018, 6018) Region Location Min X0 UL: 213
(0018, 601a) Region Location Min Y0 UL: 70
(0018, 601c) Region Location Max X1 UL: 803
(0018, 601e) Region Location Max Y1 UL: 658
(0018, 6020) Reference Pixel X0 SL: 295
(0018, 6022) Reference Pixel Y0 SL: 0
(0018, 6024) Physical Units X Direction US: 3
(0018, 6026) Physical Units Y Direction US: 3
(0018, 602c) Physical Delta X FD: 0.0238278
(0018, 602e) Physical Delta Y FD: 0.0238278
(0018, 6030) Transducer Frequency UL: 1670
---------
(0018, 6060) R Wave Time Vector FL: [313.3869934082031, 1000.0260009765625]
(0020, 000d) Study Instance UID UI: 1.2.840.113619.2.391.51208.1686298500.4.1
(0020, 000e) Series Instance UID UI: 1.2.840.113619.2.391.51208.1686298500.4.2
(0020, 0010) Study ID SH: '202306090814'
(0020, 0011) Series Number IS: '1'
(0020, 0013) Instance Number IS: '19'
(0020, 0020) Patient Orientation CS: ''
(0028, 0002) Samples per Pixel US: 3
(0028, 0004) Photometric Interpretation CS: 'YBR_FULL_422'
(0028, 0006) Planar Configuration US: 0
(0028, 0008) Number of Frames IS: '32'
(0028, 0009) Frame Increment Pointer AT: (0018, 1063)
(0028, 0010) Rows US: 708
(0028, 0011) Columns US: 1016
(0028, 0014) Ultrasound Color Data Present US: 0
(0028, 0100) Bits Allocated US: 8
(0028, 0101) Bits Stored US: 8
(0028, 0102) High Bit US: 7
(0028, 0103) Pixel Representation US: 0
(0028, 2110) Lossy Image Compression CS: '01'
(0028, 2112) Lossy Image Compression Ratio DS: '95.0'
(7fe0, 0010) Pixel Data OB: Array of 2521450 elements
(fffc, fffc) Data Set Trailing Padding OB: b'\x00\x00'
Partially you can calculate that. Note that the acquisition technique of US uses a cone beam, hence pixel size usually varies across the image. But depending on your application, I would say that the contents of the Sequence of Ultrasound Regions (0018, 6011) is your friend:
See here for reference