diff --git a/Packages/ohif-core/client/helpers/number.js b/Packages/ohif-core/client/helpers/number.js
index 9b99a13ac..433087ee6 100644
--- a/Packages/ohif-core/client/helpers/number.js
+++ b/Packages/ohif-core/client/helpers/number.js
@@ -11,3 +11,7 @@ Template.registerHelper('sum', (...values) => {
     _.each(_.initial(values, 1), value => (result += (value | 0)));
     return result;
 });
+
+Template.registerHelper('isValidNumber', value => {
+    return typeof value === 'number' && !isNaN(value);
+});
diff --git a/Packages/ohif-viewerbase/client/components/viewer/viewportOverlay/viewportOverlay.html b/Packages/ohif-viewerbase/client/components/viewer/viewportOverlay/viewportOverlay.html
index 816eb084a..590c90fac 100644
--- a/Packages/ohif-viewerbase/client/components/viewer/viewportOverlay/viewportOverlay.html
+++ b/Packages/ohif-viewerbase/client/components/viewer/viewportOverlay/viewportOverlay.html
@@ -21,7 +21,7 @@
                 <div>{{#if frameRate}}{{formatNumberPrecision frameRate 2}} FPS{{/if}}</div>
                 <div>{{imageDimensions}}</div>
                 <div>
-                    <span>{{#if location}}Loc: {{formatNumberPrecision location 2}} mm{{/if}}</span>
+                    <span>{{#if isValidNumber location}}Loc: {{formatNumberPrecision location 2}} mm{{/if}}</span>
                     <span>{{#if thickness}}Thick: {{formatNumberPrecision thickness 2}} mm{{/if}}</span>
                     <span>{{#if spacingBetweenSlices}}Spacing: {{formatNumberPrecision spacingBetweenSlices 2}} mm{{/if}}</span>
                 </div>
diff --git a/Packages/ohif-viewerbase/client/lib/seriesNavigation.js b/Packages/ohif-viewerbase/client/lib/seriesNavigation.js
index e72fe3fbd..0cd0cdb93 100644
--- a/Packages/ohif-viewerbase/client/lib/seriesNavigation.js
+++ b/Packages/ohif-viewerbase/client/lib/seriesNavigation.js
@@ -1,6 +1,6 @@
 import { Session } from 'meteor/session';
 import { OHIF } from 'meteor/ohif:core';
-// @TODO: import symbols into local scope: Studies and ViewerData
+// @TODO: import symbols into local scope: ViewerData
 
 const getStudyFromStudyInstanceUid = studyInstanceUid => {
     // @TypeSafeStudies
@@ -11,11 +11,11 @@ const getNumberOfStacks = studyInstanceUid => {
     // May not work if the Study contains non-image series?
     const study = getStudyFromStudyInstanceUid(studyInstanceUid);
 
-    if (!study || !study.series || !study.series.length) {
+    if (!study || !study.displaySets || !study.displaySets.length) {
       return;
     }
 
-    return study.series.length;
+    return study.displaySets.length;
 };
 
 const getActiveViewportIndex = () => {
@@ -48,8 +48,8 @@ const loadSeries = indexCalculator => {
 
     const study = getStudyFromStudyInstanceUid(studyInstanceUid);
 
-    const displaySetInstanceUids = study.series.map(series => {
-      return series.displaySetInstanceUid;
+    const displaySetInstanceUids = study.displaySets.map(displaySet => {
+      return displaySet.displaySetInstanceUid;
     });
 
     const currentLoadedStackIndex = displaySetInstanceUids.indexOf(displaySetInstanceUid);