Posted 11 March 2016
Until last fall, I thought of CT scans as providing clear, unambiguous, 3D images. As I’ve learned over the course of 6 CT scans in the past 4 months, it is not like that.
Interpreting the CT images requires a detailed knowledge of anatomy and what it typically looks like in a CT scan.
Yesterday I asked Dr. Ko to walk through the latest CT and explain it to me. Here’s a video I made to capture what I learned.
The video gives the appearance of showing changes through time, and that is what we all naturally expect a video to be. But this is different: the time dimension comes from the location of the “slice”, so what you are seeing is the motion of the patient through the CT machine.
The slices are taken both axially (the slice would be parallel to the ground if you were standing up) and vertically along the sagittal plane.
Animation of Axial Slices
The video is from the axial images, starting with a slice at the top of my torso, and slowly moving down to my pelvis.
Here is a sagittal image (a cross section vertically, perpendicular to the ground if standing), which is less useful but still fascinating.
I’ve also had a number of old-fashioned chest X rays, because it is part of the protocol when you show up at the emergency department with a fever. The most recent one is below.
It shows my PowerPort at the upper left, and the attached tube that goes up and over my top rib and then descends down to my heart. The port is needed for chemotherapy, because it allows for drugs to be delivered more rapidly than via an IV, and it was also used to connect the pump that I wore home for two days as part of each cycle.
The messy-looking circles down the center of my chest are the stainless steel wires that held my sternum together after the heart surgery (mitral valve repair) I had in January 2015. The bone is now fused together, so the wires aren’t needed, but taking them out would be disruptive.
The Strange World of CT Interpretation
The CT scans are read by a radiologist, who dictates a description into a voice recognition system. These results are full of technical terms, making them hard for non-medical people to read. They also have a scattering of transcription errors, which is scary when treatment decisions are being made from these reports.
I’ve had a lot of questions about the radiologist reports, and I noticed that most were written by the same person, so I inquired about getting an appointment with him to go through the CT images and his notes. He declined, saying that my doctor can ask him questions on my behalf.
Below I’ve shown excerpts from the radiologist reports for the six CT scans I’ve had since November, showing the evolution of my tumors and the variations in the reports.
Everything below is taken verbatim from the radiology reports.
Scan 1 – 11/5/15
It is unclear whether there are 2 masses identified or a single mass in the pancreas. There is a definite central low-attenuation mass likely involving the uncinate process just to the left of midline measuring 3 cm CC, 3 cm AP and 2.1 cm transverse.
There is a possible mass in the pancreatic head measuring 2.3 x 2.7 cm. There is infiltration/stranding in the fat directly adjacent to the pancreas in these locations. There is additional abnormal soft tissue identified just inferior to the duodenum at the level of the ligament of Treitz and this measures 3.3 cm transverse x 2.2 cm AP.
CONCLUSION: Findings worrisome for either pancreatic cancer or an aggressive duodenal adenocarcinoma. Pancreatic cancer is favored. Multiple pulmonary metastases are seen. There is a possible occult metastasis in the anterior right hepatic lobe adjacent to the cystic lesion causing the focal intrahepatic ductal dilatation. Additionally, several low-density lesions in the liver are indeterminate. This patient would likely benefit from a PET/CT.
Scan 2 – 11/20/15
A heterogeneously hypodense lesion in the second portion of the duodenum near the measures approximately 3.4 cm, compared to approximately 3 cm previously Wall thickening is also seen in the third portion of the duodenum, with an additional focal hypodensity along the posterior aspect of the duodenum measuring up to 3 cm, compared to 2.6 cm that abuts the abdominal aorta No evidence of obstruction.
Scan 3 – 12/7/15 (a few days after starting chemotherapy)
Significant increase in size of duodenal/periduodenal masses. The primary duodenal mass at the D2/D3 junction measures approximately 4.7 x 3.6 cm compared to 2.6 x 3.0 cm previously. Mass adjacent to the duodenojejunal junction along the undersurface, measures 4.6 x 6.3 cm compared to 2.6 x 2.0 cm previously. There is severe compromise of the duodenal lumen, however, oral contrast does traverse in the small bowel. Masses are necrotic.
Significant increase in intra and extra hepatic ductal dilatation, common hepatic duct measuring 2.2 cm. There are 2 pigtail CBD stents, one placed more centrally. Distal pigtails of both stents are in the duodenum. Slightly increase in pancreatic duct dilatation.
Scan 4 – 1/13/16 (after 3 cycles of chemotherapy)
Interval replacement of the 2 small caliber coiled biliary stents with a larger expandable stent. The lower margin of the stent appears to end at the level of the ampulla. There has been significant decompression of the biliary tree post stent replacement. Air is now seen within the intra-/extrahepatic biliary tree.
Decompression of previous pancreatic duct dilatation.
Decreased size of the hypoattenuating mass interposed between the uncinate process and proximal third portion duodenum now measuring 24 x 23 mm diameter compared with 33 mm diameter previously. Additional decrease in size in the hypoattenuating mass in the more caudal third portion duodenum now measuring 38 mm maximal diameter compared with 55 mm previously.
CONCLUSION: Significant reduction in size of the 2 discrete third portion duodenal masses compared with the recent abdomen CT, positive treatment response.
Scan 5 – 1/30/16
Stable peripancreatic masses, the more proximal measuring 33 x 19 mm diameter compared with 33 x 24 mm previously. The more distal mass measures 32 mm transverse diameter compared with 32 mm previously.
CONCLUSION: Stable duodenal masses compared with 1/13/2016
Scan 6 – 3/3/16 (after 6 cycles of chemotherapy)
Duodenal mass extends to the pancreas, with possible invasion.
Heterogeneous mass in the region of the transverse duodenum has increased in size, now measuring 4.6 x 3.4 cm, where previously it had measured 3.3 x 1.9 cm.
The second mass described on the previous report also has increased in size and now coalesces with the larger mass.
No evidence of significant obstruction, although there is mural thickening of the more proximal duodenum. Also of note, there is at least mild thickening of the wall of the colon throughout which appears to be a new finding.
Increased size of duodenal mass, suggesting progression of disease.
Left pulmonary nodule is stable.
Somewhat geographic appearing area of increased attenuation within the right hepatic lobe, which I suspect is an area of focal fatty sparing, although cannot completely exclude possibility of liver metastasis. It appears new or at least significantly increased from prior exam. As clinically indicated, MRI of the liver would exclude this possibility.
There is new mild thickening of the wall of the entire colon raising possibility of colitis. Recommend clinical correlation.