feat: Allow backslashes in UIDs in order to support DICOM Q&R (#277)

Treat backslashes in UID fields as a delimiter so multiple UIDs can be specified. When using DICOM Q&R it is possible to query a list of UIDs by using a backslash as a delimiter: https://dicom.nema.org/medical/dicom/current/output/chtml/part04/sect_C.2.2.2.2.html

packages/adapters/src/ValueRepresentation.js

@@ -1019,10 +1019,26 @@ class UniqueIdentifier extends StringRepresentation {
     }
 
     readBytes(stream, length) {
-        return this.readNullPaddedString(stream, length).replace(
-            /[^0-9.]/g,
-            ""
-        );
+        const result = this.readNullPaddedString(stream, length);
+
+        const BACKSLASH = String.fromCharCode(0x5c);
+        const uidRegExp = /[^0-9.]/g;
+
+        // Treat backslashes as a delimiter for multiple UIDs, in which case an
+        // array of UIDs is returned. This is used by DICOM Q&R to support
+        // querying and matching multiple items on a UID field in a single
+        // query. For more details see:
+        //
+        // https://dicom.nema.org/medical/dicom/current/output/chtml/part04/sect_C.2.2.2.2.html
+        // https://dicom.nema.org/medical/dicom/current/output/chtml/part05/sect_6.4.html
+
+        if (result.indexOf(BACKSLASH) === -1) {
+            return result.replace(uidRegExp, "");
+        } else {
+            return result
+                .split(BACKSLASH)
+                .map(uid => uid.replace(uidRegExp, ""));
+        }
     }
 }
 

packages/adapters/test/data.test.js

@@ -8,6 +8,7 @@ import os from "os";
 import path from "path";
 import unzipper from "unzipper";
 import followRedirects from "follow-redirects";
+import { promisify } from "util";
 
 const { https } = followRedirects;
 
@@ -595,3 +596,17 @@ it("test_custom_dictionary", () => {
     //check that all other fields were preserved, 15 original + 1 for _vr and +1 for "TrialName"
     expect(Object.keys(dataset).length).toEqual(17);
 });
+
+it("Reads DICOM with multiplicity", async () => {
+    const url =
+        "https://github.com/dcmjs-org/data/releases/download/multiplicity/multiplicity.dcm";
+    const dcmPath = path.join(os.tmpdir(), "multiplicity.dcm");
+
+    await downloadToFile(url, dcmPath);
+
+    const file = await promisify(fs.readFile)(dcmPath);
+    const dicomDict = DicomMessage.readFile(file.buffer);
+
+    expect(dicomDict.dict["00101020"].Value).toEqual([1, 2]);
+    expect(dicomDict.dict["0018100B"].Value).toEqual(["1.2", "3.4"]);
+});