A Picture Says a Thousand Words

Basically every time we perform a PET/CT scan, there are a few questions we like to ask the patient.  Namely whether if they are a diabetic, and if they are, what time did they take their insulin or hyperglycemic medication.  The other thing is, have they eaten anything within the past 6 hours.  Given the image above, what do you think happened?  Does this look like a typical PET scan using F18-FDG?

Indication:  Thyoma PET study

Findings:  Paitent did not prepare for the PET/CT examination, a follow up study is required.

Hx:  The thyoma study requires the patient to undergo presurgical radiation therapy and chemotherapy, in the attempt to increase the chances of a complete resection.  The PET/CT scans are done prior to the chemo and radiation therapy and then post surgery.  The PET scans are performed 3-4 weeks post treatment to avoid reactive responses causing false positive scans.

With this case, the PET/CT scan was performed post surgery.  The patient during the screening process denied eating prior to the test.  The blood glucose measurement did not suggest otherwise, however upon completion of the exam, the image included vast muscular uptake.  The patient confessed in having a coffee and a muffin 1 hour prior to his PET/CT injection.

Three days after the scan above, another PET/CT scan was performed.  Compare the difference.  It's not great but definitely improved.

Collateral Blood Flow

What the .....?"  Yup, that's what the tech said after the injection of MAA into the left arm, after the initial ventilation scan.

Indication:  Rule out any significant pulmonary hypertension.  Pre-op assessment.

Findings:  Preliminary flow study demonstrates extensive collateralization of the left chest wall.  Matched and unmatched perfusion defects in both lungs.  Impression, low probability for pulmonary embolism.  Possible left subclavian obstruction.

Hx:  Pulmonary hypertension is not one of the indications for a VQ scan, unless they have had a chronic history of a pulmonary embolism (PE).  The thoracic surgeon ordered this test to ensure that there were no complications before they performed an open biopsy on the left lung.  The patient had previous non Hodgkin's lymphoma, was experiencing SOB, reduced lung capactiy from the PFT study, developed hemoptysis, fever and chills.  Based on the CT and a failed FNA, the open biopsy would help to figure out if there was a relapse in the lymphoma or lung fibrosis or some other inflammatory disease.