Doctors use special imaging scans to detect sarcoidosis, a disease that can affect the heart. These scans typically require patients to wait 90 minutes after receiving a tracer injection before imaging. Researchers tested whether waiting just 60 minutes would work equally well. They studied 87 patients and found that the shorter 60-minute wait time was just as accurate at detecting cardiac sarcoidosis as the longer 90-minute wait. This discovery could help patients get faster results and reduce the time they spend in the hospital, without losing any diagnostic accuracy.

The Quick Take

  • What they studied: Whether a shorter 60-minute waiting period produces equally accurate heart imaging scans compared to the standard 90-minute waiting period for detecting cardiac sarcoidosis (a disease affecting the heart).
  • Who participated: 87 patients (45 women and 42 men) who were suspected of having cardiac sarcoidosis. All patients received special preparation including a low-carbohydrate diet, fasting, and a medication injection before their scans.
  • Key finding: The 60-minute scan was 97% accurate at detecting cardiac sarcoidosis, while the 90-minute scan was 92% accurate. This difference was not statistically significant, meaning both timeframes performed essentially the same.
  • What it means for you: If you need this type of heart imaging scan, you may be able to get results in 60 minutes instead of 90 minutes without any loss of accuracy. This could mean less time waiting at the hospital and faster answers from your doctor. However, this only applies if your heart shows adequate glucose suppression during the scan.

The Research Details

This study enrolled 87 patients who were suspected of having cardiac sarcoidosis. Each patient received an injection of a special tracer (a radioactive substance) and then underwent two imaging scans: one at 60 minutes after injection and another at 90 minutes after injection. The scans use a technology called PET/CT, which combines two types of imaging to create detailed pictures of the heart. Three different doctors, with varying levels of experience, independently reviewed all the scans without knowing which timepoint they were looking at. They classified each scan as either showing typical signs of sarcoidosis or not. The researchers then compared how well the doctors agreed with each other and how accurate each timepoint was compared to established diagnostic criteria (the Japanese Circulation Society standards).

This research approach is important because it directly compares two different protocols in the same patients, which is the strongest way to determine if a shorter procedure works as well as a longer one. By having multiple independent readers assess the scans, the researchers could determine how reliable the findings were. Using established diagnostic criteria as a reference standard ensures the results are measured against a trusted benchmark. This type of study design helps answer practical questions about whether medical procedures can be made more efficient without sacrificing quality.

The study demonstrates good reliability in several ways: the agreement between different doctors was substantial to almost perfect (κ values of 0.690-0.899), which indicates the scans were clear enough for consistent interpretation. The study used blinded readers, meaning doctors didn’t know which timepoint they were evaluating, which reduces bias. The sample size of 87 patients is reasonable for this type of comparison study. The use of established diagnostic criteria provides an objective reference standard. However, the study is relatively recent (2026) and represents a single research center’s experience, so results may need confirmation in other settings.

What the Results Show

Among patients who had adequate suppression of normal heart glucose uptake (which is necessary for accurate diagnosis), the 60-minute scan correctly identified cardiac sarcoidosis in 97% of cases (62 patients), while the 90-minute scan was accurate in 92% of cases (65 patients). The difference between these two accuracy rates was not statistically significant (p = 0.22), meaning the difference could easily be due to chance rather than a real difference between the two timepoints. The agreement between different doctors reviewing the scans was substantial, with consistency scores (Fleiss’ κ) ranging from 0.690 to 0.693. When the same doctor reviewed scans multiple times, agreement was even stronger, ranging from 0.703 to 0.899, indicating the scans were clear and interpretable. These findings suggest that the 60-minute timepoint captures the same diagnostic information as the 90-minute timepoint.

The study found that adequate myocardial (heart muscle) glucose suppression was essential for accurate diagnosis at both timepoints. Patients who achieved this suppression had excellent diagnostic accuracy at both 60 and 90 minutes. The consistency of results across readers with different levels of experience suggests that the 60-minute protocol is robust and not dependent on reader expertise. The study also demonstrated that shorter protocols may improve patient comfort and workflow efficiency in medical centers.

Previous research established that 90-minute uptake times improve the ability to distinguish disease from normal tissue by allowing more tracer accumulation in affected areas. This study builds on that knowledge by questioning whether the additional 30 minutes of waiting actually provides meaningful diagnostic improvement. The findings suggest that with proper patient preparation (low-carbohydrate diet, fasting, and heparin administration), the 60-minute timepoint may be sufficient, potentially challenging the standard recommendation for 90-minute protocols.

The study was conducted at a single medical center, so results may not apply equally to all hospitals or patient populations. The sample size of 87 patients, while reasonable, is relatively modest for establishing new clinical standards. The study required specific patient preparation (low-carbohydrate diet, fasting, and heparin injection), which may not be feasible in all clinical settings. The study only included patients with suspected cardiac sarcoidosis, so results may not apply to other conditions. The reference standard used (Japanese Circulation Society criteria) may not be universally applied in all countries. The study is very recent and has not yet been validated by other independent research groups.

The Bottom Line

Based on this research, a 60-minute uptake time appears to be sufficient for detecting cardiac sarcoidosis, provided that patients receive proper preparation (low-carbohydrate diet, fasting, and heparin administration) and that adequate heart glucose suppression is achieved. This finding suggests that medical centers may consider adopting 60-minute protocols to reduce patient wait times. However, these findings should be confirmed by additional studies before becoming standard practice. Confidence level: Moderate—this is a single-center study that needs validation.

This finding is most relevant to patients suspected of having cardiac sarcoidosis who need diagnostic imaging. It’s also important for cardiologists, nuclear medicine specialists, and hospital administrators who schedule imaging procedures. Patients with other conditions requiring similar imaging may not benefit from this finding. People without symptoms or risk factors for cardiac sarcoidosis do not need this information.

If this protocol is adopted, patients could expect to receive their imaging results approximately 30 minutes faster than with the current standard protocol. The actual time savings would be 30 minutes of waiting, though the total appointment time might be slightly longer if the hospital needs time for patient preparation and result interpretation.

Want to Apply This Research?

  • If you have been diagnosed with or are being monitored for cardiac sarcoidosis, track your imaging appointment times and results. Note the date of your scan, the type of scan performed (60-minute or 90-minute protocol), and the results. This helps you and your doctor monitor disease progression over time.
  • If your doctor recommends cardiac sarcoidosis imaging, ask whether your medical center offers the 60-minute protocol. If scheduling an appointment, inquire about the specific preparation requirements (fasting duration, diet restrictions, and any medications). Follow all pre-scan instructions carefully, as proper preparation is essential for accurate results. Set reminders for your appointment and any follow-up visits.
  • Create a health timeline in your app documenting all cardiac sarcoidosis imaging studies, including the date, protocol used (60 or 90 minutes), and results. Track any symptoms you experience between scans. Share this information with your cardiologist at each visit to monitor disease progression and treatment effectiveness over months and years.

This research describes a specialized medical imaging protocol for detecting cardiac sarcoidosis. These findings are not medical advice and should not be used for self-diagnosis. If you have symptoms of heart disease or have been told you might have sarcoidosis, consult with a cardiologist or your primary care physician. The decision to use a 60-minute versus 90-minute imaging protocol should be made by your healthcare provider based on your individual circumstances. This study represents current research and may not yet reflect standard clinical practice at all medical centers. Always follow your doctor’s recommendations regarding diagnostic testing and treatment.