fix: Ensure we take into account pixel spacing fields properly (#1555)

* fix: Ensure we take into account pixel spacing fields properly

* Rename to getPixelSpacingInformation

platform/core/src/classes/MetadataProvider.js

@@ -1,7 +1,7 @@
 import * as dcmjs from 'dcmjs';
 import queryString from 'query-string';
 import dicomParser from 'dicom-parser';
-import { getFallbackTagFromInstance } from '../utils/metadataProvider/metadataProviderFallbackTags';
+import getPixelSpacingInformation from '../utils/metadataProvider/getPixelSpacingInformation';
 import fetchPaletteColorLookupTableData from '../utils/metadataProvider/fetchPaletteColorLookupTableData';
 import fetchOverlayData from '../utils/metadataProvider/fetchOverlayData';
 
@@ -161,18 +161,6 @@ class MetadataProvider {
       return instance[naturalizedTagOrWADOImageLoaderTag];
     }
 
-    if (options.fallback) {
-      // Perhaps the tag has fallbacks?
-      const fallbackTag = getFallbackTagFromInstance(
-        naturalizedTagOrWADOImageLoaderTag,
-        instance
-      );
-
-      if (fallbackTag) {
-        return fallbackTag;
-      }
-    }
-
     // Maybe its a legacy CornerstoneWADOImageLoader tag then:
     return this._getCornerstoneWADOImageLoaderTag(
       naturalizedTagOrWADOImageLoaderTag,
@@ -218,10 +206,9 @@ class MetadataProvider {
         const { ImageOrientationPatient } = instance;
 
         // Fallback for DX images.
-        const PixelSpacing = getFallbackTagFromInstance(
+        // TODO: We should use the rest of the results of this function
-          'PixelSpacing',
+        // to update the UI somehow
-          instance
+        const { PixelSpacing } = getPixelSpacingInformation(instance);
-        );
 
         let rowPixelSpacing;
         let columnPixelSpacing;

platform/core/src/utils/metadataProvider/getPixelSpacingInformation.js

@@ -0,0 +1,90 @@
+import log from '../../log';
+
+export default function getPixelSpacingInformation(instance) {
+  // See http://gdcm.sourceforge.net/wiki/index.php/Imager_Pixel_Spacing
+
+  // TODO: Add Ultrasound region spacing
+  // TODO: Add manual calibration
+
+  // TODO: Use ENUMS from dcmjs
+  const projectionRadiographSOPClassUIDs = [
+    '1.2.840.10008.5.1.4.1.1.1', //	CR Image Storage
+    '1.2.840.10008.5.1.4.1.1.1.1', //	Digital X-Ray Image Storage – for Presentation
+    '1.2.840.10008.5.1.4.1.1.1.1.1', //	Digital X-Ray Image Storage – for Processing
+    '1.2.840.10008.5.1.4.1.1.1.2', //	Digital Mammography X-Ray Image Storage – for Presentation
+    '1.2.840.10008.5.1.4.1.1.1.2.1', //	Digital Mammography X-Ray Image Storage – for Processing
+    '1.2.840.10008.5.1.4.1.1.1.3', //	Digital Intra – oral X-Ray Image Storage – for Presentation
+    '1.2.840.10008.5.1.4.1.1.1.3.1', //	Digital Intra – oral X-Ray Image Storage – for Processing
+    '1.2.840.10008.5.1.4.1.1.12.1', //	X-Ray Angiographic Image Storage
+    '1.2.840.10008.5.1.4.1.1.12.1.1', //	Enhanced XA Image Storage
+    '1.2.840.10008.5.1.4.1.1.12.2', //	X-Ray Radiofluoroscopic Image Storage
+    '1.2.840.10008.5.1.4.1.1.12.2.1', //	Enhanced XRF Image Storage
+    '1.2.840.10008.5.1.4.1.1.12.3' // X-Ray Angiographic Bi-plane Image Storage	Retired
+  ];
+
+  const { PixelSpacing, ImagerPixelSpacing, SOPClassUID, PixelSpacingCalibrationType, PixelSpacingCalibrationDescription, EstimatedRadiographicMagnificationFactor } = instance;
+  const isProjection = projectionRadiographSOPClassUIDs.includes(SOPClassUID);
+
+  const TYPES = {
+    NOT_APPLICABLE: 'NOT_APPLICABLE',
+    UNKNOWN: 'UNKNOWN',
+    CALIBRATED: 'CALIBRATED',
+    DETECTOR: 'DETECTOR'
+  };
+
+  if (isProjection === false && !ImagerPixelSpacing) {
+    // If only Pixel Spacing is present, and this is not a projection radiograph,
+    // we can stop here
+    return {
+      PixelSpacing,
+      type: TYPES.NOT_APPLICABLE,
+      isProjection
+    };
+  } else if (isProjection && !ImagerPixelSpacing) {
+    // If only Pixel Spacing is present, and this is a projection radiograph,
+    // PixelSpacing should be used, but the user should be informed that
+    // what it means is unknown
+    return {
+      PixelSpacing,
+      type: TYPES.UNKNOWN,
+      isProjection
+    };
+  } else if (PixelSpacing && ImagerPixelSpacing && PixelSpacing === ImagerPixelSpacing) {
+    // If Imager Pixel Spacing and Pixel Spacing are present and they have the same values,
+    // then the user should be informed that the measurements are at the detector plane
+    return {
+      PixelSpacing,
+      type: TYPES.DETECTOR,
+      isProjection
+    };
+  } else if (PixelSpacing && ImagerPixelSpacing && PixelSpacing !== ImagerPixelSpacing) {
+    // If Imager Pixel Spacing and Pixel Spacing are present and they have different values,
+    // then the user should be informed that these are "calibrated"
+    // (in some unknown manner if Pixel Spacing Calibration Type and/or
+    // Pixel Spacing Calibration Description are absent)
+    return {
+      PixelSpacing,
+      type: TYPES.CALIBRATED,
+      isProjection,
+      PixelSpacingCalibrationType,
+      PixelSpacingCalibrationDescription
+    };
+  } else if (!PixelSpacing && ImagerPixelSpacing) {
+    let CorrectedImagerPixelSpacing = ImagerPixelSpacing;
+    if (EstimatedRadiographicMagnificationFactor) {
+      // Note that in IHE Mammo profile compliant displays, the value of Imager Pixel Spacing is required to be corrected by
+      // Estimated Radiographic Magnification Factor and the user informed of that.
+      // TODO: should this correction be done before all of this logic?
+      CorrectedImagerPixelSpacing = ImagerPixelSpacing.map(pixelSpacing => pixelSpacing / EstimatedRadiographicMagnificationFactor);
+    } else {
+      log.info('EstimatedRadiographicMagnificationFactor was not present. Unable to correct ImagerPixelSpacing.');
+    }
+
+    return {
+      PixelSpacing: CorrectedImagerPixelSpacing,
+      isProjection,
+    };
+  }
+
+  log.info('Unknown combination of PixelSpacing and ImagerPixelSpacing identified. Unable to determine spacing.');
+}

platform/core/src/utils/metadataProvider/metadataProviderFallbackTags.js

@@ -1,27 +0,0 @@
-import log from '../../log';
-
-function getFallbackTagFromInstance(tag, instance) {
-  if (instance[tag]) {
-    return instance[tag];
-  }
-
-  const fallbackTags = fallbackTagsMap[tag];
-
-  if (fallbackTags) {
-    for (let i = 0; i < fallbackTags.length; i++) {
-      const fallbackTag = fallbackTags[i];
-
-      if (instance[fallbackTag]) {
-        log.info(`metadata provider fallback tag ${tag} to ${fallbackTag}`);
-
-        return instance[fallbackTag];
-      }
-    }
-  }
-}
-
-const fallbackTagsMap = {
-  PixelSpacing: ['ImagerPixelSpacing'],
-};
-
-export { fallbackTagsMap, getFallbackTagFromInstance };