Nuclear Medicine and Molecular Imaging最新文献

Purpose: The growing use of ionizing radiation in medical imaging requires balancing diagnostic benefits with radiation risks. This study assesses awareness and knowledge of radiation doses and risks among Jordanians.

Methods: This cross-sectional study surveyed 582 Jordanian social media users online between December and February 2023, using 24 multiple-choice questions on demographics, radiological health risks, and precautionary awareness.

Results: The cohort consisted of 321 (55%) males and 261 (45%) females, with most patients (54%) being from the 18-30 age group. Findings revealed a 42% incidence of direct radiation exposure within the past six months, predominantly advised by physicians (82%). Notably, 94% of participants recognized the risk of radiation exposure to pregnant women's pelvic and abdominal regions. Awareness of the carcinogenic potential of radiation was high (92%), yet only 18% reported wearing protective gear during exposure. There was a significant difference between medical and non-medical respondents in the awareness of wearing protective gear (25% vs. 11%, p-value < 0.001), risk of cancer, infertility, cataracts, and the effect of spiral CT scans to 100-800 X-rays (83% vs. 69%, p-value < 0.001). In addition, 37% of medical respondents thought warning signs are enough for comprehensive explanation compared to 27% in non-medical respondents (p-value = 0.012).

Conclusion: The study reveals satisfactory awareness of medical radiation hazards among Jordanians, with disparities between medical and non-medical respondents. However, low protective gear usage and knowledge gaps indicate the need for improved education in radiology and public health campaigns on radiation safety.

Supplementary information: The online version contains supplementary material available at 10.1007/s13139-025-00919-z.

RBC scintigraphy has shown to be a sensitive imaging technique for detecting gastrointestinal bleed. There may be a time interval between the initiation of bleed and appearance of symptoms. This study can help in localizing the site of active bleed; though, false positive results may be seen. A patient of chronic liver disease presented with dark stools and falling hemoglobin who after initial management, showed focal tracer uptake in the pelvis on 99mTc-labelled RBC scintigraphy planar imaging suggesting gastrointestinal bleed. However, SPECT/CT accurately localized the tracer activity in a previously undiagnosed urinary bladder hernia in the inguinal canal and scrotum.

Objectives: The primary endpoint of this study is to establish a reliable SUVR cutoff threshold to distinguish patients with Alzheimer's disease (AD), excluding those with mild cognitive impairment (MCI), from normal control (NC) individuals using [¹⁸F]florapronol PET imaging and deep learning-based automated quantification software. The secondary endpoint is to evaluate whether combining partial volume correction (PVC) with SUVR analysis improves diagnostic accuracy in detecting AD.

Methods: A total of 141 participants, including 55 AD patients (excluding MCI) and 86 NC controls, were enrolled. Each participant underwent [¹⁸F]florapronol PET imaging, and SUVR values were calculated for six amyloid-prone brain regions using deep learning-based software. SUVRs were computed with and without PVC, using the cerebellar cortex as the reference region. Receiver operating characteristic (ROC) analysis identified optimal SUVR thresholds for distinguishing AD (excluding MCI) from NC and for determining visual positivity. Age-matched subgroup analyses ensured consistent diagnostic performance across different age groups.

Results: In the full cohort (n = 141), visual analysis achieved a sensitivity of 90.9% and specificity of 94.1% for distinguishing AD from NC. SUVR without PVC reached a similar sensitivity of 90.9% and specificity of 86.0% (optimal threshold > 1.26), while PVC-adjusted SUVR further improved accuracy with a sensitivity of 90.9% and specificity of 94.2% at a threshold of > 1.31. For visual positivity, SUVR without PVC achieved 92.7% sensitivity and 89.5% specificity, while PVC-adjusted SUVR improved these metrics to 96.4% sensitivity and 94.2% specificity. Age-matched analyses confirmed diagnostic consistency across different age groups. The visual analysis and the quantitative analysis using SUVR with PVC as the threshold were consistent in 134 out of 141 subjects (95.0%).

Conclusions: Automated SUVR quantification with PVC adjustment provides a reliable and objective method for distinguishing AD from NC, aligning closely with visual assessment accuracy and supporting clinical use of [¹⁸F]florapronol PET imaging for AD diagnosis. This standardized approach enhances diagnostic consistency, particularly in settings with limited access to PET specialists, and establishes robust SUVR thresholds for broader clinical application in amyloid PET imaging.

Purpose: Alzheimer's disease (AD) often coexists with other brain pathologies, and we aimed to classify people with AD using 18 F- Flouro-Deoxy-Glucose-Positron Emission Tomography (FDG-PET).

Method: Baseline FDG-PET data were collected as part of two large scale Phase III clinical trials of a novel tau aggregation inhibitor drug, Leuco-Methylthioninium (LMTX®). A total of 794, well-characterised probable AD subjects were included in the study and the images were classified into "typical AD"(temporoparietal hypometabolism) and "mixed" (patchy hypo-metabolism in other vascular territories of brain such as frontal and cerebellar regions along with temporo-parietal hypo-metabolism) patterns based on visual interpretation. The differences in the two groups were further assessed with region-of-interest based analysis of Standardized Uptake Value Ratio (SUVR) and automated classification using transfer learning with visual classification as the gold standard.

Results: Of the total of 794 (438 female) participants, 533 (284 female) were classified as typical AD and 261 (154 female) participants classified as mixed. A subset of 50 images each from typical and mixed subtypes were used for transfer learning and sensitivity, specificity and accuracy for one of the cross-validation loops was 94.73%, 95.23% and 95% respectively. The average accuracy to distinguish the two subtypes after 5-fold cross validation was found to be 97.5%.

Conclusions: This study is first of its kind to distinguish two subtypes of AD through visual interpretation of FDG-PET images and exploring the findings with a semi-quantitative method followed by transfer learning, which has been used to predict the two subtypes with high accuracy, sensitivity and specificity.

Purpose: Neuroendocrine tumors (NETs) can be classified into three grades based on the malignancy index identified via histological and pathological diagnosis, and ¹¹¹In-pentetreotide single photon emission computed tomography (SPECT) is effective for diagnosis. Therefore, this study aimed to distinguish between NET grade 1 (G1) and NET grade 2 (G2) based on the change in standardized uptake value (SUV) 4 and 24 h after injection in pancreatic and gastrointestinal NETs.

Methods: Twenty-two patients underwent ¹¹¹In-pentetreotide SPECT and were definitively diagnosed with pancreatic or gastrointestinal NETs. The volume of interest were set in the tumor areas 4 and 24 h after injection, and SUV_max and SUV_mean were calculated. The ⊿tumor SUV (24 h-4 h) was calculated for each G1 and G2 by subtracting the SUV 4 h from SUV 24 h.

Results: The ⊿tumor SUV_max (24 h-4 h) was 19.35 ± 23.26 in G1 and - 13.30 ± 20.26 in G2, and the ⊿tumor SUV_mean (24 h-4 h) was 7.64 ± 15.58 in G1 and - 8.89 ± 15.45 in G2. The ⊿tumor SUV_max (24 h-4 h) and ⊿tumor SUV_mean (24 h-4 h) were higher in G1 compared to G2 (p < 0.05).

Conclusion: The ⊿tumor SUV (24 h-4 h) in patients with pancreatic/gastrointestinal NET on ¹¹¹In-pentetreotide SPECT images were higher in G1 compared to G2. The ⊿tumor SUV (24 h-4 h) for pancreatic and gastrointestinal NETs may predict the malignancy grade, as determined by histological and pathological diagnosis.

Nocardiosis, an opportunistic infection occurs in immunodeficient population commonly in organ transplant recipients. Patients with risk factors likely chronic corticosteroids and immunosuppressants consumption usually have a higher tendency for disseminated infections with formation of deep abscesses at various sites in the body. Functional imaging with PET, being a whole body imaging offers information about the various sites of disease, thereby assisting the treatment planning, treatment response and also to identify the sites of biopsy. 68Ga FAPI PET serves this purpose as previous studies in various other infections have shown activated fibroblasts with increased FAP expression at the infective foci.

Purpose: Very-low-birth-weight (VLBW) infants are more likely to have poor neurodevelopmental outcomes, even if structural abnormalities are not observed during brain magnetic resonance imaging (MRI). The purpose of the present study was to determine whether cerebral glucose metabolism is correlated with neurodevelopmental outcomes in VLBW infants without structural abnormalities.

Methods: Twenty-seven VLBW infants (birth weight < 1,500 g) without structural abnormalities were prospectively enrolled. All infants underwent F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) examinations at term-equivalent ages, and the regional glucose metabolic ratios were calculated. Neurodevelopmental outcomes were assessed using the Mental Development Index (MDI) and the Psychomotor Development Index (PDI) of the Bayley Scales of Infant Development-II at a corrected age of 18-24 months. Poor neurodevelopmental outcomes were defined as an MDI or PDI score < 85.

Results: The glucose metabolic ratio in the right central region of the brain was significantly correlated with the MDI score (r = 0.505, p = 0.007). The glucose metabolic ratios in the right central region and right insula in the poor-neurodevelopmental-outcome group were significantly lower than those in the good-neurodevelopmental-outcome group (1.03 ± 0.02 vs. 1.08 ± 0.04, p = 0.004, and 1.08 ± 0.05 vs. 1.13 ± 0.05, p = 0.018, respectively). Furthermore, the right central region and insula exhibited large extent of metabolic connectivity in infants with good neurodevelopmental outcome than that in infants with poor neurodevelopmental outcome.

Conclusions: Cerebral glucose metabolism was correlated with the neurodevelopmental outcomes of VLBW infants at a corrected age of 18-24 months.

Supplementary information: The online version contains supplementary material available at 10.1007/s13139-024-00893-y.