Molecular Imaging and Radionuclide Therapy最新文献

Objectives: To investigate the amount of effective dose (ED) due to the computed tomography (CT) component of lung perfusion-single-photon emission computed tomography (Q-SPECT)/CT.

Methods: In this single-center retrospective study, imaging data were collected from the clinic database for the period 2016-2022. The 327 patients identified were aged between 20 and 94 years. Tube voltage, tube current, pitch, gantry rotation time, volume CT dose index, and dose-length product (DLP) were recorded. The DLP was then converted to an ED using the conversion factors. The comparison of the ED between two groups was performed using the Mann-Whitney U non-parametric test.

Results: ED (mean ± standard deviation, mSv) was 1.20±0.70 for the pulmonary embolism (PE) (-) and 1.54±1.04 for the PE (+) cases (p<0.05). It was observed that there was a 28% increase in the ED for the PE (+) cases. In addition, each of the PE (-) and PE (+) cases was divided into two groups according to the use of the computed tomography dose reduction (CTDR): without CTDR protocol group (non-CTDR) and with CTDR protocol group (CTDR). For those groups, ED were obtained as 0.87±0.72 and 1.55±0.47 for PE (-) cases (p<0.05); 1.56±1.17 and 1.49±0.54 for PE (+) cases (p>0.05) correspondingly. For a deeper understanding, ED was calculated for all three groups formed with different tube voltage values applied for the non-CTDR and CTDR groups.There was a 42% decrease in the ED for group 1 PE (+) compared to group 2 PE (+) (1.21±0.28, 2.07±0.91, p<0.05) and there was a 41% decrease in the ED for group 1 PE (-) compared to group 2 PE (-) cases (1.17±0.32, 1.97±0.65, p<0.05).

Conclusion: It could be concluded that the effective DR protocol is the non-CTDR protocol for the PE (-) cases and the application of the tube voltage at the level of 100 kVp for the PE (+) cases.

Adrenal adenomas are observed in up to 7% of the population and are predominantly non-functional, increased ¹⁸F-fluorodeoxyglucose (FDG) uptake is seen in only a small portion of them on ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT) imaging. In this report, we present the sequential ¹⁸F-FDG PET/CT imaging findings of 2 patients with radiologically or pathologically confirmed adrenal adenomas who had severely altered ¹⁸F-FDG uptake patterns in adrenal lesions in different imaging studies of the same patient. In light of these findings, we wanted to highlight that evaluating adrenal adenomas as cross-sectional with semi-quantitative PET/CT parameters obtained from single imaging may cause misinterpretation.

A 13-year-old male patient presented with right leg pain and walking difficulty. Contrast-enhanced magnetic resonance imaging showed a softtissue lesion between muscle groups in the anterior half of the right thigh. The excisional biopsy result ended in an inflammatory myofibroblastic tumor (IMT). The ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scan showed hypermetabolism in the multifocal soft tissue lesion and also confirmed that no other distant foci were present. A three-phase Tc-99m-methylene diphosphonate study of the region showed heterogeneously increased vascularity within the region. We described an unusual case of IMT in a pediatric patient and the importance of PET/CT scanning to delineate the lesion.

A 79-year-old man treated for prostate cancer (PCa) in 2018 with concurrent hormone therapy and radical radiotherapy (RT) was given metastasis-directed RT because of skeletal progression of PCa in 2021. On [¹⁸F]-choline positron emission tomography/computed tomography (CT) for biochemical recurrence (prostate-specific antigen level: 4.96 ng/mL), he showed significant uptake in multiple skeletal lesions and focal uptake in a left lung nodule. CT-guided biopsy revealed a sarcomatoid lung carcinoma. This case confirms that histopathological evaluation is mandatory in the event of significant radiolabeled choline uptake in a single lung nodule.

Objectives: The aim of this study was to evaluate the relationship between the types of distant metastatic spread, histopathological features, and imaging features of primary tumor on positron emission tomography/magnetic resonance imaging (PET/MRI) for primary staging in newly diagnosed breast invasive ductal carcinoma (IDC) patients.

Methods: Data from 289 female patients were retrospectively evaluated. Maximum standardized uptake value, metabolic tumor volume (MTV), total lesion glycolysis (TLG), and minimum apparent diffusion coefficient (ADC_min) values of primary tumors were obtained from PET/MRI. The patients were grouped as non-metastatic, oligometastatic (1-5 metastatic lesions) and multimetastatic (>5 metastatic lesions) disease according to the number of distant metastases, and divided into two groups as isolated bone metastasis (IBM) and mixed/soft tissue metastasis (M-SM) groups according to the sites of metastatic spread.

Results: Metabolic parameters had higher values and ADC_min had lower values in the multimetastatic and oligometastatic groups than in the non-metastatic group. MTV was the only parameter that showed significant difference between the multimetastatic and oligometastatic groups. MTV and TLG were significantly higher in the M-SM group than in the IBM group. ¹⁸F-fluorodeoxyglucose PET parameters had significantly higher values in grade 3, hormone receptor negative, human epidermal growth factor receptor 2 positive, triple negative, and highly proliferative (Ki-67 ≥14%) tumors. The prediction models that included imaging parameters to predict the presence of distant metastasis had higher discriminatory powers than the prediction models that included only histopathological parameters.

Conclusion: Primary tumors with higher metabolic-glycolytic activity and higher cellularity were more aggressive and had higher metastatic potential in breast IDC. Compared with histopathological parameters alone, the combination of imaging parameters and histopathological features of primary tumors may help to better understand tumor biology and behavior.

Objectives: The aim of this study was to evaluate the correlation between clinical histopathologic features and micropapillary (MP) ratio with the maximum standardized uptake value (SUV_max) derived from ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in treatment naïve breast cancer.

Methods: Twenty-nine patients diagnosed with breast cancer with a MP component who underwent PET/CT imaging before any local and/or systemic treatment were included in this retrospective study. All clinical histopathological features were recorded. SUV_max values were measured from ¹⁸F-FDG PET images for primary tumors and metastatic axillary lymph nodes.

Results: MP component percentage did not correlate with any clinical histopathological features except age. At early ages, the MP component ratio was significantly higher. Our results showed that there is no significant correlation between the SUV_max value and MP component percentage.

Conclusion: A high SUV_max value is generally expected in aggressive malignancies. However, this assumption may not be valid for the MP subgroup, which has an aggressive course compared to other subgroups in breast cancer.

Objectives: The aim of this study was to analyze the systolic part of the left ventricular (LV) volume curve obtained by gated myocardial perfusion imaging with the formula used in exponential decay and to investigate the clinical value of the results.

Methods: One hundred fifty eight patients were retrospectively enrolled in the study. The study group was divided into three groups as normal, ischemia, and infarct. The systolic portion of the LV volume curve was also analyzed using the exponential decay formula. The scintigraphic parameter obtained using this formula is called the ejection constant (Ec).

Results: The Ec results were 1.8±0.8, 2.7±0.9, 3.5±1 in infarct, ischemia, and normal groups, respectively, and the difference in Ec results between the groups was statistically significant (p≤0.001).

Conclusion: It appears that Ec may play a clinical role as a scintigraphic parameter in the evaluation of systolic functions of the left ventricle.

A 7-year-old boy with known diagnosis of hereditary spherocytosis and ulcerative colitis was referred for ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography after detection of a 28 mm lesion suspicious for malignancy in spleen on upper abdomen magnetic resonance imaging (MRI). As an incidental finding, a moderately increased uptake of ¹⁸F-FDG was observed in periportal region with no definable mass. MRI revealed compatible findings with "periportal cuffing" as described on ultrasonography.

A 61-year-old male patient, who had undergone radical prostatectomy, underwent ⁶⁸Ga labeled prostate-specific membrane antigen (PSMA) positron emission tomography/computerized tomography (PET/CT) for evaluation of suspected biochemical recurrence of prostate cancer (PCa). PET/CT scan showed increased ⁶⁸Ga PSMA expressions in hypodense mass lesions in both adrenal gland localizations. An adrenal gland tru-cut biopsy was performed for the right side, which showed poor-differentiated carcinoma metastases associated with the patient's high-grade PCa. As far as we could determine based on an extensive literature search, this is the second case in which isolated adrenal metastasis was detected by ⁶⁸Ga PSMA PET/CT study in a patient with PCa.

Rectal neuroendocrine carcinomas constitute <1% of all neuroendocrine carcinomas and <1% of all gastrointestinal tract malignancies. Cutaneous metastases of rectal neuroendocrine carcinoma are rarer than visceral metastases. We represent a 71-year-old man who was diagnosed with neuroendocrine tumor grade 3 originating from the rectum 1 year ago. He was referred for ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography for restaging after 6 cycles of chemotherapy and radiotherapy. Intensely increased ¹⁸F-FDG uptake in the right cutaneous inguinal region was consistent with neuroendocrine carcinoma metastasis with biopsy from the same region.