diff --git a/readimc/mcd_file.py b/readimc/mcd_file.py
index d94c14a..e9d492d 100644
--- a/readimc/mcd_file.py
+++ b/readimc/mcd_file.py
@@ -201,6 +201,7 @@ def read_slide(
         if data_start_offset == data_end_offset == 0:
             return None
         data_start_offset += 161
+        data_end_offset -= 1
         if data_start_offset >= data_end_offset:
             raise IOError(
                 f"MCD file '{self.path.name}' corrupted: "
@@ -236,6 +237,7 @@ def read_panorama(
         if data_start_offset == data_end_offset == 0:
             return None
         data_start_offset += 161
+        data_end_offset -= 1
         if data_start_offset >= data_end_offset:
             raise IOError(
                 f"MCD file '{self.path.name}' corrupted: "
@@ -276,6 +278,7 @@ def read_before_ablation_image(
         if data_start_offset == data_end_offset == 0:
             return None
         data_start_offset += 161
+        data_end_offset -= 1
         if data_start_offset >= data_end_offset:
             raise IOError(
                 f"MCD file '{self.path.name}' corrupted: "
@@ -318,6 +321,7 @@ def read_after_ablation_image(
         if data_start_offset == data_end_offset == 0:
             return None
         data_start_offset += 161
+        data_end_offset -= 1
         if data_start_offset >= data_end_offset:
             raise IOError(
                 f"MCD file '{self.path.name}' corrupted: "