Feasibility of 18FDG PET in the cardiac inflammation.

The aim of the study was to assess the feasibility of 18FDG PET in cardiac inflammation with a particular focus on the delayed scan. Thirty-five consecutive 18FDG PET scans of patients with suspected or confirmed cardiac inflammation were retrospectively reviewed. The patients were referred for PET because of endocarditis (n = 16) or sarcoidosis (n = 19). Among them four patients had two consecutive for follow up and treatment control (two patients with sarcoidosis, two with endocarditis). In all of the cases a standard head to mid-thigh scan was performed 45-60 min after 18FDG injection as well as a delayed heart scan 1 h after the standard imaging was performed. 18FDG PET confirmed active inflammation in 10 out of 35 scans. Delayed scans in positive cases showed SUVmax value increase, but did not have an impact on the result, neither they did in negative cases-no significant differences between standard and delayed scan were found. Interestingly in 5 out of 14 cases with suspected endocarditis PET revealed the extracardiac inflammation focus, thus changing initial diagnosis. 18FDG PET also indicated which prosthesis caused inflammation if there were many. In the sarcoidosis group the aim was to confirm or exclude heart involvement (13 scans) or to assess the response to the steroid therapy (6 scans) in patients with previously confirmed sarcoidosis. PET revealed active heart disease in 3 initial scans, and 1 follow up scan. 18FDG PET is a valuable imaging method for the cardiac inflammation assessment. It adequately localises the active inflammation site. Also, since it is a whole-body scan it may detect the extracardiac inflammation foci, which in some cases may change the initial diagnosis. In our study the delayed scans showed no added value.

Feasibility of myocardial perfusion imaging studies in morbidly obese patients with a cadmium-zinc-telluride cardiac camera.

BACKGROUND: A novel cardiac SPECT camera with cadmium-zinc-telluride (CZT) based technology has a fixed array of semiconductor detectors paired with pinhole collimators focused on the heart. Image acquisition in obese patients can be challenging because of much smaller detector field of view compared to conventional gamma cameras. The aim of this study was to evaluate the impact on high body mass on the feasibility of CZT myocardial perfusion imaging (MPI). The additional aim was to investigate the mechanism of the banana-shaped/obesity artifact, as referred to in literature, and to attempt at simulating it on a phantom study. MATERIAL AND METHODS: Study group consisted of 43 patients with morbid obesity (BMI ≥ 40 kg/m2). All these patients underwent myocardial perfusion imaging on both CZT cardiac camera and general purpose SPECT/CT gamma camera. Control group consisted of all patients who underwent myocardial perfusion imaging on CZT camera throughout one calendar year and whose BMI was lower than 40 kg/m2. In this group, all repeated studies were re-analyzed for estimating the frequency of heart mispositioning in the camera field of view. The number of studies performed was 1180. A static cardiac phantom was used to simulate a banana-shaped artifact. A series of phantom acquisitions during which the phantom position was altered in the camera field of view was performed. RESULTS: In control group, 3.7% of all cardiac scintigrams required repetition, 18.9% of which were repeated due to wrong heart positioning; median BMI in this group of patients was 36.0. A banana-shaped artifact was observed in one female patient with BMI 36.0. In morbid obesity group, 32.6% of the studies were non-diagnostic with "truncation effect" on Scan Quality Control (QC). Median BMI in patients with diagnostic scans was 42.0, while in patients with not acceptable quality control test it was 45.0 (p < 0.05). Banana-shaped artifacts were observed in 5 non-diagnostic studies. In a phantom study an artifact of banana shape was obtained when gantry was distant from the phantom and target was on the edge of the camera field of view and was slightly truncated. CONCLUSIONS: Problem with heart mispositioning during imaging on the CZT camera affects less than 1% of all performed studies. Morbid obesity is not a contraindication to perform myocardia.

The diagnostic efficacy and safety of stress-only supine and prone myocardial perfusion imaging with a dedicated cardiac gamma camera in patients with suspected or known coronary artery disease.

BACKGROUND: Myocardial perfusion scintigraphy remains one of the substantial noninvasive diagnostic methods in coronary artery disease. Recent technological advancement allowed to create novel semiconductor, dedicated cardiac gamma camera with better spatial resolution and higher energy resolution, resulting in the reduction of radiation burden and acquisition time. The aim of this study was to evaluate the efficacy and safety of stress-only supine and prone MPS with a cardiac gamma camera in patients with suspected or known coronary artery disease. MATERIAL AND METHODS: A total number of 203 consecutive patients with suspected or known coronary artery disease, who underwent MPS were enrolled in the study. The patients without perfusion abnormalities on stress supine and prone MPS scans had no rest MPS, in the remaining patients two-day stress-rest imaging was performed. The group of 160 patients with one-year follow up was subjected to final analysis. RESULTS: Stress-only protocol of myocardial perfusion imaging was performed in 72 patients, 88 patients underwent two-day stress and rest myocardial perfusion scintigraphy. In 46 out of 72 stress-only group of patients, prone study did not affect further proceedings. However, in over 1/3 of cases (26/72), prone scans resulted in abstaining from rest imaging. One year follow-up revealed no sudden cardiac deaths or myocardial infarctions in both (stress-only and stress-rest) groups. Revascularization was performed most often in the double-positive group - patients with significant ischaemia on myocardial perfusion images and chest pain or electrocardiographic changes or both during the stress test. In this double-positive group, all 11 patients had coronary angiography (two of them prior to myocardial perfusion scintigraphy), nine of them had subsequent revascularization. CONCLUSIONS: In patients with no significant perfusion abnormalities on stress scans omitting rest study is safe with very good one-year risk prognosis of acute cardiac events and allows to limit the radiation exposure and procedure duration. Additional prone acquisitions are valuable supplements in determining the decision of safe early completion of myocardial perfusion imaging.

Utility of single-photon emission tomography/computed tomography for sentinel lymph node localization in breast cancer patients.

OBJECTIVES: Sentinel lymph node (SLN) mapping is currently a routine technique in breast cancer management and preoperative scintigraphic imaging plays a crucial role in the process of SLN detection. The guidelines recommend performing planar acquisition and optional single-photon emission tomography/computed tomography (SPECT/CT) imaging. The aim of this study was to verify whether routine performing of SPECT/CT in addition to planar imaging increases the sensitivity of SLN detection in patients with early-stage breast cancer. The secondary aims were to compare radionuclide SLN imaging with intraoperative SLN detection and identify clinical and histopathological factors affecting the SLN detection rate. MATERIALS AND METHODS: A total of 153 early-stage breast cancer patients underwent lymph node scintigraphy in the years 2007-2013. Breast cancer patients with staging T1-2N0M0 were included. Planar and SPECT/CT lymphoscintigraphy were performed on the day before the surgery. The data on presence or absence of SLN, their number and localization were recorded for both methods and compared with each other as well as with intraoperative blue dye staining and histopathological findings. RESULTS: SPECT/CT identified SLN in 119/153 and planar scintigraphy in 114/153 patients. Identification rates were 77.7 and 74.5%, respectively. Intraoperative lymph node assessment identified SLN in 76/126 cases with an identification rate of 60.3%. Identification rates for second echelon lymph node were 34.6% for hybrid imaging and 21.2% for planar scintigraphy. Statistical analysis did not yield a significant difference in diagnostic accuracy between these methods; however, the Wilcoxon signed-rank test showed that SPECT/CT significantly increases SLN identification rate compared with planar scintigraphy and intraoperative detection. Histopathological examination of excised SLN showed that 22 nodes were metastatic. SPECT/CT visualized all of these, whereas planar imaging and intraoperative lymph node detection procedure visualized 19 and 18, respectively. No clinical and histopathological factors affecting SLN detection rate were identified. CONCLUSION: Hybrid SPECT/CT lymphatic mapping yields a high SLN detection rate in patients with early-stage breast cancer and provides lymph node localization details. It identifies more SLN than planar imaging and intraoperative SLN detection. However, its limited superiority over the remaining two methods does not support its routine use for SLN localization. We suggest using SPECT/CT for SLN detection in case of equivocal planar imaging results.

Long bone metastases as predictors of survival in patients with metastatic renal cancer.

BACKGROUND: The aim of this study was to assess the prevalence of long bone metastases in renal cancer patients and to evaluate their utility as predictors of survival in this group. MATERIAL AND METHODS: This retrospective study included 20 patients with metastatic renal cancer and bone metastases. The patients were referred for regular bone scintigraphy in order to assess disease spread in the skeleton. The patients were divided into two groups: those with 1) metastases in the skeleton (including long bones) and those with 2) metastases in the axial skeleton only. RESULTS: Bone scintigraphy imaging was performed regularly up to 81 months from the first positive bone scan. During that time 11 deaths (8 among patients with long bone lesions) were recorded. Kaplan-Meyer curves showed that patients with long bone metastases tend to have lower survival probability in comparison to the ones with metastases in other bones. CONCLUSIONS: Bone metastases localization seems to influence survival in patients with renal cancer. Long bone-involving spread of the disease is associated with worse survival probability than the spread to the other bones.