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What Does My CT Scan Report Indicate?
Question: Hi, doctor,
I have lung lesions which were first found 10 years ago. The lesions should be caused by TB infection, but I was never treated for TB.
I had a CT scan recently using a SIMENS SOMATOM Definition Flash with IV contrast (Iodine). The reading of my lesion in DICOM file using a DICOM viewer ranges from 20 to 180. However, the reading I got from my radiologist on the same lesion can be as high as 426, and my radiologist uses Simens syngo via VA30A software to produce the reading. Which reading should I use as the hounsfield reading of my lesion? How much will the contrast increase the reading? Is my lesion considered calcified? And where can I get more information on this?
Thanks for the help.
I have lung lesions which were first found 10 years ago. The lesions should be caused by TB infection, but I was never treated for TB.
I had a CT scan recently using a SIMENS SOMATOM Definition Flash with IV contrast (Iodine). The reading of my lesion in DICOM file using a DICOM viewer ranges from 20 to 180. However, the reading I got from my radiologist on the same lesion can be as high as 426, and my radiologist uses Simens syngo via VA30A software to produce the reading. Which reading should I use as the hounsfield reading of my lesion? How much will the contrast increase the reading? Is my lesion considered calcified? And where can I get more information on this?
Thanks for the help.
Brief Answer:
Please upload CT scan CD or DVD online for review of images and HU values.
Detailed Answer:
Hi XXXX,
Thanks for writing in to us.
I have read through your query in detail.
Lung lesions found 10 years ago and showing no significant change in size are not signs of active TB. However the images should be seen in detail before giving a proper opinion.
Having used SIEMENS machine for last 10 years, I understand your concern on measuring the HU values of your lung lesion.
May I bring to your notice that when measuring HU values of a lesion, it is best measured where there is more homogeneous attenuation or density. To avoid mistakes, it is best to calculate the mean HU values in a region. While 20 HU applies to fluids, 180 HU shows that the density is that of a calcification. Since HU values of 20 to 180 is a broad range, I would like to see the lesion myself to be more certain. There are many false measurements that can occur if not measured properly.
The value of 426 HU indicates dense calcification.
Being a Radiologist myself, it is less likely that they will make a mistake when calculating HU values and SIEMENS software is reliable.
If I accept your radiologist's view of 426 HU then it is dense calcification and most likely an old healed calcified granuloma which indicates inactive condition.
Contrast can increase the HU values depending on blood components and this increase can be up to 60 to 80 HU.
To answer your question, I would like to see the CT scan images myself and give you my best opinion. May I request you to please upload the CT scan CD or DVD contents online through Dropbox or Google drive and send me download link.
I will download all images and then discuss each point in detail. It will help me to check and confirm HU values and give you a clear answer on your problems.
Regards,
Dr.Vivek
Please upload CT scan CD or DVD online for review of images and HU values.
Detailed Answer:
Hi XXXX,
Thanks for writing in to us.
I have read through your query in detail.
Lung lesions found 10 years ago and showing no significant change in size are not signs of active TB. However the images should be seen in detail before giving a proper opinion.
Having used SIEMENS machine for last 10 years, I understand your concern on measuring the HU values of your lung lesion.
May I bring to your notice that when measuring HU values of a lesion, it is best measured where there is more homogeneous attenuation or density. To avoid mistakes, it is best to calculate the mean HU values in a region. While 20 HU applies to fluids, 180 HU shows that the density is that of a calcification. Since HU values of 20 to 180 is a broad range, I would like to see the lesion myself to be more certain. There are many false measurements that can occur if not measured properly.
The value of 426 HU indicates dense calcification.
Being a Radiologist myself, it is less likely that they will make a mistake when calculating HU values and SIEMENS software is reliable.
If I accept your radiologist's view of 426 HU then it is dense calcification and most likely an old healed calcified granuloma which indicates inactive condition.
Contrast can increase the HU values depending on blood components and this increase can be up to 60 to 80 HU.
To answer your question, I would like to see the CT scan images myself and give you my best opinion. May I request you to please upload the CT scan CD or DVD contents online through Dropbox or Google drive and send me download link.
I will download all images and then discuss each point in detail. It will help me to check and confirm HU values and give you a clear answer on your problems.
Regards,
Dr.Vivek
Above answer was peer-reviewed by :
Dr. Vaishalee Punj
Hi doctor,
Thank you for the information.
I am a bit of hesitate to upload my personal medical data to public domain.
My largest lung lesion spans 7 slices with interval of 0.8mm. Below are some reading I obtained from the 5 slices in the middle and the slides are from top to bottom.
1. mean=102.38, SD=56.18, max=196, min=18, #pixels= 21
2. mean=59.36, SD=32.48, max=144, min=22, #pixels= 22
3. mean=55.13, SD=21.86, max=95, min=32, #pixels= 22
4. mean=89.57, SD=67.29, max=232, min=16, #pixels= 23
5. mean=10.67, SD=23.72, max=70, min=-27, #pixels=18
Are the above information enough to judge whether the lesion is calcified or not?
Does readings in the DICOM file include the enhancement caused by the contrast? If yes, then does it mean that the real HU reading is 60~80 HU smaller than the readings above?
Thanks a lot for the help.
Thank you for the information.
I am a bit of hesitate to upload my personal medical data to public domain.
My largest lung lesion spans 7 slices with interval of 0.8mm. Below are some reading I obtained from the 5 slices in the middle and the slides are from top to bottom.
1. mean=102.38, SD=56.18, max=196, min=18, #pixels= 21
2. mean=59.36, SD=32.48, max=144, min=22, #pixels= 22
3. mean=55.13, SD=21.86, max=95, min=32, #pixels= 22
4. mean=89.57, SD=67.29, max=232, min=16, #pixels= 23
5. mean=10.67, SD=23.72, max=70, min=-27, #pixels=18
Are the above information enough to judge whether the lesion is calcified or not?
Does readings in the DICOM file include the enhancement caused by the contrast? If yes, then does it mean that the real HU reading is 60~80 HU smaller than the readings above?
Thanks a lot for the help.
Brief Answer:
Your lung nodule is small and calcified and is not a concern
Detailed Answer:
Hi XXXX,
Thanks for writing back with an update.
I appreciate your interest and understanding about CT scan images.
As you have sent me HU densities from 5 slices, it is clear that the walls of the lesion have a maximum HU of 196 (slice 1) and 232 (slice 4). From this information, I can guess that your lung nodule is having calcified components. As the entire lesion might be approximately 4 mm in size. At first I reassure to you that this size of a lesion is least likely to be that of active disease. Even the HU values are falling in the calcified range at some points. I am almost sure that you are having a healed calcified nodule which is small in size.
Since the lesion is less than 5 mm, there might be lot of errors in measuring the HU values by an inexperienced individual like you. As a Radiologist is an expert in recording HU values in such small lesions, I would accept his reading of 426 without any hesitation.
With concern to the contrast enhancement characteristics, generally speaking, a lesion can be well enhancing if difference in HU values between plain and contrast images is 60 to 80. If the difference is between 30 and 60 then it can be called moderately enhancing. If the difference is 10 to 30 HU then it is mildly enhancing. Enhancement up to 10 HU is usually minimally enhancing. So enhancement is based on the difference in HU values between plain and post contrast images.
Coming to your case, the enhancement characteristic is not a concern in small calcified nodules like the one you have.
In conclusion, you have a tiny calcified nodule which is remotely present from past 10 years and has no clinical significance in the present.
Regards,
Dr.Vivek
Your lung nodule is small and calcified and is not a concern
Detailed Answer:
Hi XXXX,
Thanks for writing back with an update.
I appreciate your interest and understanding about CT scan images.
As you have sent me HU densities from 5 slices, it is clear that the walls of the lesion have a maximum HU of 196 (slice 1) and 232 (slice 4). From this information, I can guess that your lung nodule is having calcified components. As the entire lesion might be approximately 4 mm in size. At first I reassure to you that this size of a lesion is least likely to be that of active disease. Even the HU values are falling in the calcified range at some points. I am almost sure that you are having a healed calcified nodule which is small in size.
Since the lesion is less than 5 mm, there might be lot of errors in measuring the HU values by an inexperienced individual like you. As a Radiologist is an expert in recording HU values in such small lesions, I would accept his reading of 426 without any hesitation.
With concern to the contrast enhancement characteristics, generally speaking, a lesion can be well enhancing if difference in HU values between plain and contrast images is 60 to 80. If the difference is between 30 and 60 then it can be called moderately enhancing. If the difference is 10 to 30 HU then it is mildly enhancing. Enhancement up to 10 HU is usually minimally enhancing. So enhancement is based on the difference in HU values between plain and post contrast images.
Coming to your case, the enhancement characteristic is not a concern in small calcified nodules like the one you have.
In conclusion, you have a tiny calcified nodule which is remotely present from past 10 years and has no clinical significance in the present.
Regards,
Dr.Vivek
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
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