NUCLEAR MEDICINE REVIEW最新文献

Background: About 30% of patients with disseminated differentiated thyroid cancer (DTC) may experience a loss of iodine uptake. It is associated with higher aggressiveness of the tumour and a reduced 10-year survival rate. The diagnosis of non-radioiodine avid DTC metastases remains a diagnostic challenge. A helpful technique for this diagnosis is positron emission tomography with 2-[¹⁸F]fluoro-2-deoxy-D-glucose (PET/CT with [¹⁸F]FDG). On the other hand, there are still discussions about the clinical value of using exogenous thyroid-stimulating hormone (TSH) stimulation before PET/CT with [¹⁸F]FDG. The aim of the study was the assessment of the usefulness of PET/CT with [¹⁸F]FDG under TSH suppression and stimulation of TSH performed in the detection of non-radioiodine avid DTC metastases, as well as determination of the thyroglobulin concentration under suppression and stimulation of TSH, which influences the result of PET/CT with [¹⁸F]FDG in patients with non-radioiodine avid DTC.

Material and methods: Retrospective analysis of 37 PET/CT with [¹⁸F]FDG performed in patients with DTC diagnosed and treated at the Department of Endocrinology and Isotope Therapy of the Military Institute of Medicine from January 2018 to July 2020. Of these, PET/CT with [¹⁸F]FDG under exogenous rhTSH stimulation was performed in 22 patients and PET/CT with [¹⁸F]FDG under TSH suppression in 15 was performed. In all analyzed patients, the result of diagnostic whole-body scintigraphy (WBS) using 80 MBq ¹³¹I under rhTSH stimulation was negative, and the concentration of thyroglobulin after stimulation (sTg) was greater than 1.0 ng/mL.

Results: In the group of patients examined under TSH suppression, non-radioiodine avid in PET/CT with [¹⁸F]FDG were found in 6 out of 15 patients (40%) and in the group of patients examined under rhTSH stimulation in 10 out of 22 patients (45%). The differences between the groups were not statistically significant. The analysis of the receiver operating characteristic (ROC) curves allowed to determine the cut-off point for the positive result of PET/CT performed under TSH suppression with sTg concentration of 11.03 ng/mL. In the group of studies performed under rhTSH stimulation, the cut-off point for sTg was 6.3 ng/mL. There was no statistically significant difference between the baseline thyroglobulin (natTg) and sTg levels and the positive PET/CT result. The administration of rhTSH before the PET/CT examination also had no statistically significant effect on the maximum standard uptake value (SUVmax) of the dominant lesion identified in the PET/CT.

Conclusions: 1) PET/CT with [¹⁸F]FDG is a useful tool for detection of non-radioiodine avid recurrence and/or metastases of DTC. 2) The concentration of natTg and sTg is highly correlated with a positive result of PET/CT with [¹⁸F]FDG. 3) The concentration of natTg is comparable with sTg in predicting a pos

We reported 99m-Tc phytate accumulation in the pyelocalyceal system of the kidney in the lymphoscintigraphic images of a 3.5 months-old male infant with chylous ascites, which was mistaken with the site of lymph leakage. SPECT/CT localized activity in the para-aortic region to the renal pelvis and on delayed images, this was disappeared. Our case illustrates the added value of SPECT/CT for the differentiation of possible false-positive findings in lymphoscintigraphy.

Fever of Unknown Origin (FUO) is a vexing clinical problem. Diagnosis of aetiology is essential for definitive management. A wide array of infective, inflammatory, malignant and miscellaneous pathologies can cause FUO. Hybrid imaging with 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET-CT) is now an integral part of FUO management because of its ability to demonstrate the cause in a large proportion of cases. The authors present the case of a 42-year-old male, where an infected fistula-in-ano was detected as the cause of FUO on 18F-FDG PET-CT.

Background: The authors aimed to elucidate the effect of liver space-occupying lesions (SOL) on the quantitative index of the hepatic reserve, calculated using the dynamic planar image (LHLplanar), and a three-dimensional quantitative index (LHLSPECT) calculated using quantitative combined modality single-photon emission computed tomography (SPECT/CT).

Material and methods: Water balloons of different volumes that simulated liver SOL were placed in various positions in the combined cardiac-liver phantom to examine the effects of liver SOL on visualization and quantitative indicators (LHLplanar and LHLSPECT). A 200 mL water balloon was placed in the anterior right, posterior right, left medial and left lateral lobes in the liver phantom to compare LHLplanar and LHLSPECT values with and without liver SOL at each position. Subsequently, volumes of those in the front of the right lobe were changed to 50 mL, 100 mL, 200 mL, and 400 mL, followed by statistically comparing LHLplanar and LHLSPECT values in the presence and absence of liver SOL.

Results: Despite the variation in the degree of defect accumulation with the location of the balloon when using frontal planar imaging, quantitative SPECT/CT imaging identified all defects. Multiple comparison analysis revealed that unlike LHLSPECT, the LHLplanar values changed according to liver SOL position and volume.

Conclusions: Liver SOL position and volume may affect the hepatic reserve assessments performed using LHLplanar values. In contrast, LHLSPECT is calculated using quantitative SPECT/CT and considers the effects of scattering and attenuation corrections. Therefore, LHLSPECT is a more accurate quantitative indicator of hepatic reserve than LHLplanar and is expected to facilitate future clinical research.

The authors reported the case of 69 years old woman presented with subclinical hyperthyroidism. 99m-Tc pertechnetate scan showed the abnormal focus of hot uptake in the left lobe, suggestive of a hyperfunctioning toxic thyroid nodule. Surgical treatment was advised because of the size of the nodule as a more applicable solution. Histological findings showed papillary thyroid carcinoma.

Background: Psoriasis is a chronic inflammatory disorder with an increased risk for coronary artery disease (CAD). This retrospective study aimed to evaluate the rate of myocardial ischaemia in patients with psoriasis subjected to myocardial perfusion imaging (MPI).

Material and methods: Twelve patients with moderate to severe psoriasis that had MPI were compared to 395 MPIs randomly retrieved from our MPIs pool data. All patients had a [99mTc]tetrofosmin stress - rest single-photon emission computer tomography ([99mTc]SPECT). Summed difference scores (SDS) were calculated for stress (SSS), rest (SRS) and their difference (SDS = SSS - SRS).

Results: There was no significant difference in the frequency of abnormal MPI SPECT outcomes between patients with vs. without psoriasis (6/12 vs 214/395 respectively; p = 0.778). From the evaluation of SSS, SRS and SDS, only the SDS scores of inadequately compensated resting perfusion defects were significantly lower in patients with psoriasis (p = 0.012).

Conclusions: Patients with moderate-to-severe psoriasis had a similar rate of abnormal SSS scans compared to control patients. However, the SDS scans were significantly lower in patients with psoriasis indicating compromised reversibility of resting perfusion defects. Larger controlled studies are needed to verify these observations.

Double primary lung cancer (DPLC) is a rare occurrence of primaries of different histologies or the same histology in different lobes in absence of advanced nodal or distant metastasis. It could be synchronous or metachronous. They are frequently misdiagnosed as metastasis or recurrence. This study presents the staging [¹⁸F]Fluorodeoxyglucose positron emission tomography-computed tomography findings in a case of a 74-year-old man with DPLC of different histologies.