Artificial Intelligence Analysis Using MRI and PET Imaging in Gliomas: A Narrative Review

The lack of early detection and a high rate of recurrence/progression after surgery are defined as the most common causes of a very poor prognosis of Gliomas. The developments of quantification systems with special regards to artificial intelligence (AI) on medical images (CT, MRI, PET) are under evaluation in the clinical and research context in view of several applications providing different information related to the reconstruction of imaging, the segmentation of tissues acquired, the selection of features, and the proper data analyses. Different approaches of AI have been proposed as the machine and deep learning, which utilize artificial neural networks inspired by neuronal architectures. In addition, new systems have been developed using AI techniques to offer suggestions or make decisions in medical diagnosis, emulating the judgment of radiologist experts. The potential clinical role of AI focuses on the prediction of disease progression in more aggressive forms in gliomas, differential diagnosis (pseudoprogression vs. proper progression), and the follow-up of aggressive gliomas. This narrative Review will focus on the available applications of AI in brain tumor diagnosis, mainly related to malignant gliomas, with particular attention to the postoperative application of MRI and PET imaging, considering the current state of technical approach and the evaluation after treatment (including surgery, radiotherapy/chemotherapy, and prognostic stratification).

18F-FDG PET-Derived Volume-Based Parameters to Predict Disease-Free Survival in Patients with Grade III Breast Cancer of Different Molecular Subtypes Candidates to Neoadjuvant Chemotherapy

We investigated whether baseline [¹⁸F] Fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)-derived semiquantitative parameters could predict disease-free survival (DFS) in patients with grade III breast cancer (BC) of different molecular subtypes candidate to neoadjuvant chemotherapy (NAC). For each ¹⁸F-FDG-PET/CT scan, the following parameters were calculated in the primary tumor (SUVmax, SUVmean, MTV, TLG) and whole-body (WB_SUVmax, WB_MTV, and WB_TLG). Receiver operating characteristic (ROC) analysis was used to determine the capability to predict DFS and find the optimal threshold for each parameter. Ninety-five grade III breast cancer patients with different molecular types were retrieved from the databases of the University Hospital of Padua and the University Hospital of Ferrara (luminal A: 5; luminal B: 34; luminal B-HER2: 22; HER2-enriched: 7; triple-negative: 27). In luminal B patients, WB_MTV (AUC: 0.75; best cut-off: WB_MTV > 195.33; SS: 55.56%, SP: 100%; p = 0.002) and WB_TLG (AUC: 0.73; best cut-off: WB_TLG > 1066.21; SS: 55.56%, SP: 100%; p = 0.05) were the best predictors of DFS. In luminal B-HER2 patients, WB_SUVmax was the only predictor of DFS (AUC: 0.857; best cut-off: WB_SUVmax > 13.12; SS: 100%; SP: 71.43%; p < 0.001). No parameter significantly affected the prediction of DFS in patients with grade III triple-negative BC. Volume-based parameters, extracted from baseline ¹⁸F-FDG PET, seem promising in predicting recurrence in patients with grade III luminal B and luminal B- HER2 breast cancer undergoing NAC.

Artificial Intelligence in Breast Cancer: A Systematic Review on PET Imaging Clinical Applications

BACKGROUND

18F-FDG PET/CT imaging represents the most important functional imaging method in oncology. European Society of Medical Oncology and the National Comprehensive Cancer Network guidelines defined a crucial role of 18F-FDG PET/CT imaging for local/locally advanced breast cancer. The application of artificial intelligence on PET images might potentially contributes in the field of precision medicine.

OBJECTIVE

This review aims to summarize the clinical indications and limitations of PET imaging for comprehensive artificial intelligence in relation to breast cancer subtype, hormone receptor status, proliferation rate, and lymphonodal (LN)/distant metastatic spread, based on recent literature.

METHODS

A literature search of the Pubmed/Scopus/Google Scholar/Cochrane/EMBASE databases was carried out, searching for articles on the use of artificial intelligence and PET in breast tumors. The search was updated from January 2010 to October 2021 and was limited to original articles published in English and about humans. A combination of the search terms "artificial intelligence", "breast cancer", "breast tumor", "PET", "Positron emission tomography", "PET/CT", "PET/MRI", "radiomic","texture analysis", "machine learning", "deep learning" was used.

RESULTS

Twenty-three articles were selected following the PRISMA criteria from 139 records obtained from the Pubmed/Scopus/Google Scholar/Cochrane/EMBASE databases according to our research strategy. The QUADAS of 30 full-text articles assessed reported seven articles that were excluded for not being relevant to population and outcomes and/or for lower level of evidence. The majority of papers were at low risk of bias and applicability. The articles were divided per topic, such as the value of PET in the staging and re-staging of breast cancer patients, including new radiopharmaceuticals and simultaneous PET/MRI.

CONCLUSION

Despite the current role of AI in this field remains still undefined, several applications for PET/CT imaging are under development, with some preliminary interesting results particularly focused on the staging phase that might be clinically translated after further validation studies.

The Value of Semiquantitative Parameters Derived from 18F-FDG PET/CT for Predicting Response to Neoadjuvant Chemotherapy in a Cohort of Patients with Different Molecular Subtypes of Breast Cancer

Pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) is a strong prognostic factor in breast cancer (BC). The aim of this study was to investigate whether semiquantitative parameters derived from baseline [¹⁸F]Fluorodeoxyglucose ([¹⁸F]FDG) positron emission computed tomography/computed tomography (PET/CT) could predict pCR after NAC and survival outcomes in patients affected by different molecular subtypes of BC. We retrospectively retrieved patients from the databases of two Italian hospitals (Centre A: University Hospital of Ferrara; Centre B: University of Padua) meeting the following inclusion criteria: (1) diagnosis of BC; (2) history of NAC; (3) baseline [¹⁸F]FDG PET/CT performed before the first cycle of NAC; (4) available follow-up data (response after NAC and survival information). For each [¹⁸F]FDG PET/CT scan, semiquantitative parameters (SUVmax, SUVmean, MTV and TLG) related to the primary tumor (B), to the reference lesion for both axillary (N) and distant lymph node (DN), and to the whole-body burden of disease (WB) were evaluated. Patients enrolled were 133: 34 from centre A and 99 from centre B. Patients' molecular subtypes were: 9 luminal A, 49 luminal B, 33 luminal B + HER-2, 10 HER-2 enriched, and 32 triple negative (TNBC). Luminal A and HER-2 enriched BC patients were excluded from the analysis due to the small sample size. pCR after NAC was achieved in 47 patients (41.2%). [¹⁸F]FDG PET/CT detected the primary tumor in 98.3% of patients and lymph node metastases were more frequently detected in Luminal B subgroup. Among Luminal B patients, median SUVmean_B values were significantly higher (p = 0.027) in responders (7.06 ± 5.9) vs. non-responders (4.4 ± 2.1) to NAC. Luminal B + HER-2 non-responders showed a statistically significantly higher median MTV_B (7.3 ± 4.2 cm³ vs. 3.5 ± 2.5 cm³; p = 0.003) and TLG_B (36.5 ± 24.9 vs. 18.9 ± 17.7; p = 0.025) than responders at baseline [¹⁸F]FDG PET/CT. None of the semiquantitative parameters predicted pCR after NAC in TNBC patients. However, among TNBC patients who achieved pCR after NAC, 4 volumetric parameters (MTV_B, TLG_B, MTV_WB and TLG_WB) were significantly higher in patients dead at follow-up. If confirmed in further studies, these results could open up a widespread use of [¹⁸F]FDG PET/CT as a baseline predictor of response to NAC in luminal B and luminal B + HER-2 patients and as a prognostic tool in TNBC.

A systematic review comparing lymphoscintigraphy and magnetic resonance imaging techniques in the assessment of peripheral lymphedema

BACKGROUND

Peripheral lymphedema represents a disabilitating condition affecting the lymphatic system of the limbs resulting from impaired drainage and excessive lymphatic fluid accumulation in the interstitial spaces. Lymphoscintigraphy stands as the imaging modality of the first choice to investigate patients with peripheral lymphedema. Nevertheless, in recent times, magnetic resonance imaging (MRI) techniques have also been applied to assess patients with lymphedema.

OBJECTIVE

The present systematic review aimed to appraise the available evidence providing a head-to-head comparison between lymphoscintigraphy and MRI techniques in peripheral lymphedema.

METHOD

A systematic literature search was performed using the PubMed database and Cochrane Central Register of Controlled Trials (CENTRAL). The eligibility criteria for the articles to be included in the qualitative synthesis were: 1) a study cohort or a subset of patients with a clinical diagnosis of peripheral lymphedema (either upper or lower limb); 2) execution of both MR imaging and lymphoscintigraphy in the same subset of patients. The methodological quality of the studies was assessed by an investigator using the "Quality Assessment of Diagnostic Accuracy Studies" tool, v. 2 (QUADAS-2).

RESULTS

Overall, 11 studies were ultimately included in the quantitative analysis. No meta-analysis was performed due to the heterogeneous patient samples, the different study aims of the retrieved literature, and the limited number of available articles. In the diagnosis of upper limb extremity lymphedema, the sensitivity of MRI techniques appears superior to that of lymphoscintigraphy. Comparative studies in the lower limbs are still scarce but suggest that MRI may increase the diagnostic accuracy for lymphedema.

CONCLUSION

The available literature on patients with lymphedema evaluated with both lymphoscintigraphy and MRI does not allow definite conclusions on the superiority of one imaging technique over the other one. Further studies including well-selected patient samples are still necessary to compare the accuracy of these imaging modalities. Since MRI techniques seem to provide complementary findings to lymphoscintigraphy, it would be conceivable to acquire both imaging exams in patients with peripheral lymphedema. Furthermore, studies evaluating the clinical impact of adding MRl to the diagnostic workup are warranted.

Detection of sentinel lymph node in vulvar cancer using 99mTc-labeled colloid lymphoscintigraphy, blue dye, and indocyanine-green fluorescence: a meta-analysis of studies published in 2010-2020

OBJECTIVES

Sentinel lymph node (SLN) biopsy is widely accepted in the surgical staging of early vulvar cancer, although the most accurate method for its identification is not yet defined. This meta-analysis aimed to determine the technique with the highest pooled detection rate (DR) for the identification of SLN and compare the average number of SLNs detected by planar lymphoscintigraphy (PL), single-photon emission computed tomography/computed tomography (SPECT/CT), blue dye and indocyanine green (ICG) fluorescence.

METHODS

The meta-analysis was conducted according to the PRISMA guideline. The search string was: "sentinel" and "vulv*", with date restriction from 1st January 2010 until Dec 31st, 2020. Three investigators selected studies based on: (1) a study cohort or a subset of a minimum of 10 patients with vulvar cancer undergoing either PL, SPECT/CT, blue-dye, or ICG fluorescence for the identification of SLN; (2) the possibility to extrapolate the DR or the average number of SLNs detected by a single technique (3) no evidence of other malignancies in the patient history.

RESULTS

A total of 30 studies were selected. In a per-patient and a per-groin analysis, the DR for SLN of PL was respectively 96.13% and 92.57%; for the blue dye was 90.44% and 66.21%; for the ICG, the DR was 91.90% and 94.80%. The pooled DR of SPECT/CT was not calculated, since only two studies were performed in this setting. At a patient-based analysis, no significant difference was documented among PL, blue dye, and ICG (p = 0.28). At a per-groin analysis, PL and ICG demonstrated a significantly higher DR compared to blue dye (p < 0.05). The average number of SLNs, on a per-patient analysis, was available only for PL and ICG with a median number of 2.61 and 1.78 lymph nodes detected, respectively, and no significant statistical difference.

CONCLUSIONS

This meta-analysis favors the use of ICG and PL alone and in combination over blue dye for the identification of the SLN in vulvar cancer. Future studies may investigate whether the combined approach allows the highest DR of SLN in patients with vulvar cancer.

Radiomics Analysis of Brain [18F]FDG PET/CT to Predict Alzheimer's Disease in Patients with Amyloid PET Positivity: A Preliminary Report on the Application of SPM Cortical Segmentation, Pyradiomics and Machine-Learning Analysis

BACKGROUND

Early in-vivo diagnosis of Alzheimer's disease (AD) is crucial for accurate management of patients, in particular, to select subjects with mild cognitive impairment (MCI) that may evolve into AD, and to define other types of MCI non-AD patients. The application of artificial intelligence to functional brain [¹⁸F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography(CT) aiming to increase diagnostic accuracy in the diagnosis of AD is still undetermined. In this field, we propose a radiomics analysis on advanced imaging segmentation method Statistical Parametric Mapping (SPM)-based completed with a Machine-Learning (ML) application to predict the diagnosis of AD, also by comparing the results with following Amyloid-PET and final clinical diagnosis.

METHODS

From July 2016 to September 2017, 43 patients underwent PET/CT scans with FDG and Florbetaben brain PET/CT and at least 24 months of clinical/instrumental follow-up. Patients were retrospectively evaluated by a multidisciplinary team (MDT = Neurologist, Psychologist, Radiologist, Nuclear Medicine Physician, Laboratory Clinic) at the G. Giglio Institute in Cefalù, Italy. Starting from the cerebral segmentations applied by SPM on the main cortical macro-areas of each patient, Pyradiomics was used for the feature extraction process; subsequently, an innovative descriptive-inferential mixed sequential approach and a machine learning algorithm (i.e., discriminant analysis) were used to obtain the best diagnostic performance in prediction of amyloid deposition and the final diagnosis of AD.

RESULTS

A total of 11 radiomics features significantly predictive of cortical beta-amyloid deposition (n = 6) and AD (n = 5) were found. Among them, two higher-order features (original_glcm_Idmn and original_glcm_Id), extracted from the limbic enthorinal cortical area (ROI-1) in the FDG-PET/CT images, predicted the positivity of Amyloid-PET/CT scans with maximum values of sensitivity (SS), specificity (SP), precision (PR) and accuracy (AC) of 84.92%, 75.13%, 73.75%, and 79.56%, respectively. Conversely, for the prediction of the clinical-instrumental final diagnosis of AD, the best performance was obtained by two higher-order features (original_glcm_MCC and original_glcm_Maximum Probability) extracted from ROI-2 (frontal cortex) with a SS, SP, PR and AC of 75.16%, 80.50%, 77.68%, and 78.05%, respectively, and by one higher-order feature (original_glcm_Idmn) extracted from ROI-3 (medial Temporal cortex; SS = 80.88%, SP = 76.85%, PR = 75.63%, AC = 78.76%.

CONCLUSIONS

The results obtained in this preliminary study support advanced segmentation of cortical areas typically involved in early AD on FDG PET/CT brain images, and radiomics analysis for the identification of specific high-order features to predict Amyloid deposition and final diagnosis of AD.

The Utility of Conventional Amino Acid PET Radiotracers in the Evaluation of Glioma Recurrence also in Comparison with MRI

AIM

In this comprehensive review we present an update on the most relevant studies evaluating the utility of amino acid PET radiotracers for the evaluation of glioma recurrence as compared to magnetic resonance imaging (MRI).

METHODS

A literature search extended until June 2020 on the PubMed/MEDLINE literature database was conducted using the terms "high-grade glioma", "glioblastoma", "brain tumors", "positron emission tomography", "PET", "amino acid PET", "[¹¹C]methyl-l-methionine", "[¹⁸F]fluoroethyl-tyrosine", "[¹⁸F]fluoro-l-dihydroxy-phenylalanine", "MET", "FET", "DOPA", "magnetic resonance imaging", "MRI", "advanced MRI", "magnetic resonance spectroscopy", "perfusion-weighted imaging", "diffusion-weighted imaging", "MRS", "PWI", "DWI", "hybrid PET/MR", "glioma recurrence", "pseudoprogression", "PSP", "treatment-related change", and "radiation necrosis" alone and in combination. Only original articles edited in English and about humans with at least 10 patients were included.

RESULTS

Forty-four articles were finally selected. Conventional amino acid PET tracers were demonstrated to be reliable diagnostic techniques in differentiating tumor recurrence thanks to their high uptake from tumor tissue and low background in normal grey matter, giving additional and early information to standard modalities. Among them, MET-PET seems to present the highest diagnostic value but its use is limited to on-site cyclotron facilities. [¹⁸F]labelled amino acids, such as FDOPA and FET, were developed to provide a more suitable PET tracer for routine clinical applications, and demonstrated similar diagnostic performance. When compared to the gold standard MRI, amino acid PET provides complementary and comparable information to standard modalities and seems to represent an essential tool in the differentiation between tumor recurrence and other entities such as pseudoprogression, radiation necrosis, and pseudoresponse.

CONCLUSIONS

Despite the introduction of new advanced imaging techniques, the diagnosis of glioma recurrence remains challenging. In this scenario, the growing knowledge about imaging techniques and analysis, such as the combined PET/MRI and the application of artificial intelligence (AI) and machine learning (ML), could represent promising tools to face this difficult and debated clinical issue.

Impact on the long-term prognosis of FDG PET/CT in luminal-A and luminal-B breast cancer

PURPOSE

The aim of the present study was to explore the prognostic role of 2- deoxy-2-[18F]fluoro-D-glucose PET (FDG PET)/CT in recurrent luminal A and luminal B breast cancer.

MATERIALS AND METHODS

From two institutional databases, we retrospectively retrieved data about breast cancer patients undergoing FDG PET/CT between 2011 and 2018 for the assessment of recurrency. Molecular subtypes of breast cancer were defined based on the expression of estrogen, progesterone, human epidermal growth factor receptor 2 (HER2)-b receptors and proliferation index. Overall survival (OS, intended as the time from PET/CT and the time of death) was registered for each patient, by checking the medical charts. Parametric and survival analyses were computed.

RESULTS

Data of 179 patients were retrieved. Sixty-three patients had luminal A, 88 luminal B and 28 luminal B/He breast cancer. At the time of PET/CT scan, cancer antigen (CA) 15.3 levels was within the normal range in 119 patients, whereas it was increased in 60 patients. FDG PET/CT results were suggestive for disease recurrence in 114 (63.7%) patients. The median time lapse from the FDG PET/CT scan to the last clinical follow-up visit was 51 months (1-192 months). Patients with evidence of a PET/CT scan suggestive for disease recurrence showed a significantly shorter OS (P < 0.001) compared to patients with no PET/CT evidence of recurrence, in each subset of luminal breast cancer. Moreover, PET/CT was able to stratify the prognosis of patients independently from the level of tumor marker.

CONCLUSION

These data suggest that FDG PET/CT may be an attractive prognostic tool in recurrent breast cancer. Our study supports its prognostic role both in luminal A and B-type molecular subtypes, regardless of the CA 15.3 levels.

[18F] Fluorothymidine Positron Emission Tomography Imaging in Primary Brain Tumours: A Systematic Review

PURPOSE

This review aimed to summarize the available literature on the clinical application of [¹⁸F] FLT PET imaging in primary brain tumours.

METHODS

A comprehensive search strategy based on Pubmed/Medline, Scopus, Web of Science, Cochrane Library, Google Scholar, and the Embase databases was carried on using the following search string: ('3` Fluorothymidine'/exp OR 'FLT' OR '[81F]-FLT' OR '[¹⁸F] Fluorothymidine') AND ('pet'/exp OR 'pet' OR 'positron emission tomography') AND ('glioma'/exp OR 'glioma' OR 'brain tumour'/exp OR 'brain tumour'). The search was updated till March 2021 and only articles in English and studies investigating the clinical applications of [¹⁸F] FLT PET and PET/CT in primary brain tumours were considered eligible for inclusion.

RESULTS

The literature search ultimately yielded 52 studies included in the systematic review, with main results as follows: a) the uptake of [¹⁸F] FLT may guide stereotactic biopsy but does not discriminate between grade II and III glioma. b) [¹⁸F] FLT uptake and texture parameters correlate with overall survival (OS) in newly diagnosed gliomas. c) In patients with recurrent glioma, proliferative volume (PV) and tumour-to-normal brain (T/N) uptake ratio are independent predictors of survival. d) Patients demonstrating response to therapy at [¹⁸F] FLT PET scan show longer OS compared to non-responders. e) [¹⁸F] FLT PET demonstrated good performance in discriminating tumour recurrence from radionecrosis. However, controversial results exist in comparative literature examining the performance of [¹⁸F] FLT vs. other radiotracers in the assessment of recurrence.

CONCLUSION

[¹⁸F] FLT PET imaging has demonstrated potential benefits for grading, diagnostic and prognostic purposes, despite the small sample size studies due to the relatively low availability of the radiotracer.

Impact of COVID-19 Pandemic on Cardiovascular Testing in Asia

Background

The coronavirus disease-2019 (COVID-19) pandemic significantly affected management of cardiovascular disease around the world. The effect of the pandemic on volume of cardiovascular diagnostic procedures is not known.

Objectives

This study sought to evaluate the effects of the early phase of the COVID-19 pandemic on cardiovascular diagnostic procedures and safety practices in Asia.

Methods

The International Atomic Energy Agency conducted a worldwide survey to assess changes in cardiovascular procedure volume and safety practices caused by COVID-19. Testing volumes were reported for March 2020 and April 2020 and were compared to those from March 2019. Data from 180 centers across 33 Asian countries were grouped into 4 subregions for comparison.

Results

Procedure volumes decreased by 47% from March 2019 to March 2020, showing recovery from March 2020 to April 2020 in Eastern Asia, particularly in China. The majority of centers cancelled outpatient activities and increased time per study. Practice changes included implementing physical distancing and restricting visitors. Although COVID testing was not commonly performed, it was conducted in one-third of facilities in Eastern Asia. The most severe reductions in procedure volumes were observed in lower-income countries, where volumes decreased 81% from March 2019 to April 2020.

Conclusions

The COVID-19 pandemic in Asia caused significant reductions in cardiovascular diagnostic procedures, particularly in low-income countries. Further studies on effects of COVID-19 on cardiovascular outcomes and changes in care delivery are warranted.

Radiomics and Prostate MRI: Current Role and Future Applications

Multiparametric prostate magnetic resonance imaging (mpMRI) is widely used as a triage test for men at a risk of prostate cancer. However, the traditional role of mpMRI was confined to prostate cancer staging. Radiomics is the quantitative extraction and analysis of minable data from medical images; it is emerging as a promising tool to detect and categorize prostate lesions. In this paper we review the role of radiomics applied to prostate mpMRI in detection and localization of prostate cancer, prediction of Gleason score and PI-RADS classification, prediction of extracapsular extension and of biochemical recurrence. We also provide a future perspective of artificial intelligence (machine learning and deep learning) applied to the field of prostate cancer.

Initial results of the use of a novel semiquantitative parameter in three-phase bone scan to predict 99mTc-HMPAO-labeled leukocyte scintigraphy in patients with unilateral total knee replacement

OBJECTIVES

The aim of the study was to predict the results of 99mTc-hexamethylpropyleneamine oxime (HMPAO)-labeled autologous leukocytes scintigraphy assessing count ratios in the perfusion (Pr) and blood-pool (BPr) phase images in three-phase bone scan (3PBSr) between the prosthetic knee and the 'healthy' knee and a novel semiquantitative parameter (P/BP ratio) in patients with unilateral knee arthroplasty.

METHODS

Patients with unilateral knee arthroplasty and available 3PBS and 99mTc-HMPAO-labeled autologous leukocytes scintigraphic images were searched in two hospitals (A and B). In center A, the perfusion phase was not available. Regions of interest (ROI) were delineated in the perfusion (P) and blood-pool (BP) phase images, incorporating the prosthetic region and applying an isocontour (40% of the maximum pixel activity); corresponding mirror ROIs were placed on the healthy knee. The P/BP ratio was calculated as {[(Pr/BPr) × 100] - 100}. Receiver operator curves (ROCs) were generated for each semiquantitative parameter to identify the optimal cutoff for predicting the results of the autologous leukocytes scintigraphy.

RESULTS

In the whole group (79 patients), BPr demonstrated an area under the curve (AUC) of 0.722 (optimal cutoff = 1.43). In center A (52 patients), BPr demonstrated an AUC of 0.737 (cutoff = 1.43), whereas, in center B (27 patients), AUC for BPr was 0.718 (cutoff = 1.6). A better diagnostic performance was obtained selecting Pr (AUC = 0.918; cutoff = 2.34) and P/BP ratio (AUC = 0.947; cutoff = 26.5%) for the discrimination between septic and aseptic loosening.

CONCLUSIONS

The novel P/BP ratio seems to be a promising semiquantitative parameter to predict septic loosening. These findings warrant confirmation in larger patient samples.

Comparison of 99mTc-Labeled Colloid SPECT/CT and Planar Lymphoscintigraphy in Sentinel Lymph Node Detection in Patients with Melanoma: A Meta-Analysis

We compared the detection rate (DR) for sentinel lymph nodes (SLN), the number of SLNs and the subjects with additional SLNs of single-photon emission computed tomography (SPECT/CT) and planar lymphoscintigraphy (PL) in patients with melanoma. Furthermore, we evaluated the impact of SPECT/CT on surgical plans. Articles containing head-to-head comparisons between SPECT/CT and PL were searched in Pubmed/MEDLINE and Scopus. The literature search was updated until December 31st, 2019. DR was calculated on a per patient-based analysis; the studies were pooled by their odds ratios (ORs) with a random effects model to assess the significance of difference (p < 0.05). The number of additional SLNs (calculated as the relative risk) and pooled proportion of patients with additional SLNs were investigated. The pooled ratio of surgical procedures influenced by the SPECT/CT findings was calculated. Seventeen studies with 1438 patients were eligible for the calculation of DR of SPECT/CT and PL. The average DR was 98.28% (95% confidence interval (95% CI): 97.94-99.19%) for the SPECT/CT and 95.53% (95% CI: 92.55-97.77%) for the PL; OR of 2.31 (95% CI: 1.66-4.18, p < 0.001) in favor of the SPECT/CT. There was a relative risk of a higher number of SLNs (1.13) for the SPECT/CT and 17.87% of patients with additional SLNs were detected by SPECT/CT. The average impact of SPECT/CT on surgery resulted in 37.43% of cases. This meta-analysis favored SPECT/CT over PL for the identification of SLNs in patients with melanoma due to a higher DR, reproducibility, number of SLNs depicted, proportion of patients with additional SLNs and the impact on the surgical plan. However, PL remains a good option due to the high values of the DR for SLNs.

Sentinel Node Identification in Melanoma: Current Clinical Impact, New Emerging SPECT Radiotracers and Technological Advancements. An Update of the Last Decade

BACKGROUND

Melanoma is the most lethal skin cancer with a mortality rate of 262 cases per 100.000 cases. The sentinel lymph node (SLN) is the first lymph node draining the tumor. SLN biopsy is a widely accepted procedure in the clinical setting since it provides important prognostic information, which helps patient management, and avoids the side effects of complete lymph node dissection. The rationale of identifying and removing the SLN relies on the low probability of subsequent metastatic nodes in case of a negative histological exam performed in the SLN.

DISCUSSION

Recently, new analytical approaches, based on the evaluation of scintigraphic images are also exploring the possibility to predict the metastatic involvement of the SLN. 99mTc-labeled colloids are still the most commonly used radiotracers but new promising radiotracers, such as 99mTc- Tilmanocept, are now on the market. In the last decades, single photon emission computed tomography- computerized tomography (SPECT/CT) has gained wider diffusion in clinical departments and there is large evidence about its superior diagnostic accuracy over planar lymphoscintigraphy (PL) in the detection of SLN in patients with melanoma. Scientists are also investigating new hybrid techniques combining functional and anatomical images for the depiction of SLN but further evidence about their value is needed.

CONCLUSION

This review examined the predictive and prognostic factors of lymphoscintigraphy for metastatic involvement of SLN, the currently available and emerging radiotracers and the evidence of the additional value of SPECT/CT over PL for the identification of SLN in patients with melanoma. Finally, the review discussed the most recent technical advances in the field.

Perineal stapled prolapse resection for full-thickness external rectal prolapse: a multicentre prospective study

AIM

Many different surgical techniques have been reported for the surgical treatment of full-thickness external rectal prolapse. Perianal stapled prolapse resection (PSP) is a relatively newly reported technique for full thickness external rectal prolapse. The aim of this prospective multicentre study was to evaluate the results of this procedure.

METHOD

Consecutive patients who underwent a PSP resection for full-thickness external rectal prolapse at five centres were recruited to the study. Median operating time, hospital stay, complications, recurrence and functional results according to the Wexner Incontinence Scale and obstructive defaecation syndrome score were recorded.

RESULTS

There were 27 patients treated by PSP. The median Wexner incontinence score improved from 10 presurgery to 5 after surgery (P < 0.001); the median obstructed defaecation syndrome score improved from 12 presurgery to 5 (range 4-10) after surgery (P < 0.001). A laparoscopically assisted procedure was performed in three patients (11.1%). The median number of cartridges used was six (range four to nine). The median operating time was 48 min. Early complications occurred in six patients (22.2%) and late complications in two (7.4%). The median length of hospital stay was 5 days. The recurrence rate at a median follow-up of 30.3 months was 14.8%.

CONCLUSION

PSP appears to be an easy, fast and safe procedure. Early functional results are good. The recurrence rate compares favourably with other perineal procedures like the Delorme or the Altemeier operations. Long-term functional results need to be investigated further.

124I-MIBG: a new promising positron-emitting radiopharmaceutical for the evaluation of neuroblastoma

Neuroblastoma is the most common extra-cranial solid tumor in pediatric patients. Despite the established role of 123I-MIBG and 131I-MIBG scintigraphy in this tumor, only limited data are available regarding the use of 124I-metaiodobenzylguanidine (MIBG) positron emission tomography (PET)/computed tomography (CT). We present our preliminary experience with 124I-MIBG PET/CT: two pediatric patients affected by neuroblastoma, who underwent 124I-MIBG PET/CT for pre-therapy distribution evaluation and restaging purposes. We aimed to evaluate whether 124I-MIBG PET/CT can detect as many or more neuroblastoma lesions than 123I/131I-MIBG imaging. Our cases show promising results, although further validation and standardization of 124I-MIBG PET/CT are required.

Serum Levels of Cortisol, Immunoglobulin, and C-reactive Protein in Burn Patients

Thermal injury is known to induce alterations in the immune system, but the precise mechanisms have yet to be elucidated. It has been shown that thermal injury in more than 20% of the total body surface area (TBSA) leads to disturbances in the cortisol metabolism and the equilibrium of the hypothalamic-pituitary-adrenal axis. We investigated the temporal relationship between serum cortisol levels, C-reactive protein, and immunoglobulin levels in the post-burn period. Twenty-one adult burn patients (mean age, 52 ± 17 yrs) were included in the study (TBSA, 10-80%); nine developed sepsis and five died. The nonseptic group consisted of twelve patients. Thirty healthy blood donors served as controls. Our results suggest that increased cortisol and decreased immunoglobulin levels could be related to severe sepsis and clinical outcome.

Medical ethics, clinical research, and special aspects in nuclear medicine

Medical ethics is the science of survival. It studies the working out of judgments on right or wrong referred to the human being as a biological entity interacting with the whole ecosystem. Medical ethics in clinical research raises numerous moral and technical issues. Methodological aspects are essential for carrying out the aim of clinical research. Medical ethics documents are inspired by the Nuremberg Code and culminate in the recently updated Helsinki Declaration of 1964. In Italy 2 ministerial decrees in 1997 and 1998 laid the basis for the work of a medical ethics committee. They acknowledge the European Good Clinical Practice Guidelines and set professional needs within ethical committees. In clinical research the use of ionising radiation merits special consideration. In the recent past, serious human rights abuses in radiation experiments of the 1950s and 1960s have been found. As regards research in this field we can refer to the publication of the International Commission on Radiological Protection (ICRP) and to the report of the World Health Organisation (WHO). Legislative decree no. 187 of May 26, 2000, which transposed the 97/43/ EURATOM Directive represents the most comprehensive and recent normative reference to clinical research using ionising radiation. However, law no. 39 of March 1, 2002 is important for the partial modifications of previous decrees (art. 108 of L.D. no. 230 of March 17, 1995 and, art. 4 and attachment III of L.D. no. 187 of May 26). In this paper medical ethics, research, methodological issues and aspects of ionizing radiation are discussed.

Plasma homocysteine and inflammation in elderly patients with cardiovascular disease and dementia

Increased levels of plasma total homocysteine (tHcy) may play a role in both cardiovascular diseases (CVD) and old-age dementias via enhancement of vascular inflammation. However, the association between plasma tHcy and serum C-reactive protein (sCRP), taken as a marker of low-grade inflammation, is still uncertain. We investigated this association in normal aging, CVD, and dementia, and examined whether it was modified by the presence of two major comorbid diseases of older age: chronic obstructive pulmonary disease (CPOD) and peptic ulcer (PU). Six hundred-twenty-seven individuals aged > or = 65 yr (74+/-7 yr) were selected for this study: 373 healthy controls; 160 patients with CVD but no evidence of comorbid diseases (CVD+/comorbidity-); 46 patients with CVD and concurrent CPOD and/or PU (CVD+/comorbidity+); and 48 patients with dementia. A positive association between plasma tHcy and serum CRP, independent of several confounders (socio-demographic status, known tHcy and sCRP determinants, inflammation markers, traditional vascular risk factors), was found for CVD+/comorbidity+ (p=0.001; not affected by dementia type) and dementia (p=0.001; not affected by dementia type), but not for CVD+/comorbidity- and controls. The results suggest that the association between plasma tHcy and sCRP is more an aspecific reflection of poor health than a specific correlate of vascular inflammation.

COMMON POLYMORPHISMS IN METHYLENETETRAHYDROFOLATE REDUCTASE (MTHFR): RELATIONSHIPS WITH PLASMA HOMOCYSTEINE CONCENTRATIONS AND COGNITIVE STATUS IN ELDERLY NORTHERN ITALIAN SUBJECTS

Hyperhomocysteinemia may be a risk factor for cognitive impairment. Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in homocysteine (Hcy) metabolism. Both the MTHFR 677C-->T and the 1298A-->C polymorphisms are associated with mild hyperhomocysteinemia, particularly in conditions of low folate status. The prevalence of these MTHFR polymorphisms and their relationships with plasma total Hcy (tHcy), serum folate and cognitive function was evaluated in 194 elderly Italian individuals: 122 healthy controls (73.8 +/- 7.1 years of age), 24 cognitively- impaired- not-demented individuals (78.6 +/- 9.3 years), and 48 subjects with Alzheimer dementia (AD = 26), vascular dementia (VD =22; 85.5 +/- 7.0 years). Twenty-one percent of all subjects were homozygous for 677C-->T and 7 % for 1298A-->C polymorphism. No significant relationship was found betweenMTHFR polymorphisms and age, cognitive status and type of dementia. Plasma tHcy did not differ significantly by MTHFR genotypes, but, subjects of all genotypes with low serum folate (<12 nmole/l) had higher plasma tHcy (p < 0.001), than subjects with high serum folate (>= 12 nmole/l). The study suggests that 677C-->T and 1298A-->C polymorphisms are common in the Northern Italian population, but do not significantly affect plasma tHcy levels of elderly individuals, even under conditions of low folate status. The lack of association of age and cognitive function with MTHFR genotypes argues against a negative selection for these polymorphisms.

The clock-drawing test in elderly Italian community dwellers: associations with sociodemographic status and risk factors for vascular cognitive impairment

To evaluate whether performance in the clock-drawing test (CDT) is associated with sociodemographic status and risk factors for cognitive impairment, we examined 744 Italian community dwellers aged > or =65 (73 +/- 6) years scoring > or =24 on the MMSE. CDT was scored by two different methods, the Sunderland and the Wolf-Klein methods. Sociodemographic, lifestyle, clinical and biochemical variables were also recorded. For both scoring methods, lower CDT scores were associated with age, poor education, increased serum C-reactive protein and history of cancer. Associations of lower CDT scores with increased serum glucose and history of cerebrovascular disease were also found for the method with the highest sensitivity to cognitive impairment. This study shows that in elderly community dwellers, CDT may be not totally free from sociodemographic biases, and that it is associated with risk factors for cognitive impairment and frailty.

Easy Medic: an Internet application for the general practitioner

A research project has been carried out to develop a client server application which supplies the general practitioner (GP) with a 'personal digital assistant' (hand-held mobile computer) to connect to Web servers at a hospital site through the Internet. This allows the doctor to book medical examinations, hospital admissions and manage patient data. The application used advanced object-oriented techniques, on both the client and the server side. The connection to a Web server was achieved through GSM wireless cellular telephones using standard Internet protocols (HTTP, TCP/IP and CGI). Conventional telephone lines can be used as well. Other application modules on the client side provided patients medical record supervision, GP schedule management, general information about hospitals and clinics, and pharmacy consultation. These services should help GPs in their daily work. Moreover, the quality of health-care resource management and cost supervision should improve, since each GP 'transaction' is automatically entered in realtime into a database at the server. The services are under test in the health-care system of an urban area in southern Italy.