fix(seg): multiframe SEG (#4890)

extensions/cornerstone-dicom-seg/src/getSopClassHandlerModule.ts

@@ -177,8 +177,13 @@ async function _loadSegments({
     throw new Error('referencedDisplaySet is missing for SEG');
   }
 
-  const { instances: images } = referencedDisplaySet;
-  const imageIds = images.map(({ imageId }) => imageId);
+  let { imageIds } = referencedDisplaySet;
+
+  if (!imageIds) {
+    // try images
+    const { images } = referencedDisplaySet;
+    imageIds = images.map(image => image.imageId);
+  }
 
   // Todo: what should be defaults here
   const tolerance = 0.001;