[18F]DOPA PET for lesion definition and contouring using different thresholds in patients with gliomas.

BACKGROUND: Amino-acid (AA) PET has recently been endorsed by the ESTRO-EANO guidelines for RT-planning in glioblastomas, with recommended lesion-to-brain-ratio thresholds (1.6-1.8) derived from a biopsy-controlled FET-PET study. We aimed to compare target definition at [18F]DOPA-PET between the ESTRO-EANO thresholds and other biological-tumor-volume (BTV) thresholds (derived from the striatum) typically used in [18F]DOPA-PET. METHODS: A retrospective analysis was conducted on glioma patients scanned with [18F]DOPA-PET/CT at our center between April 2021 and January 2024. 3D BTV was semi-automatically computed using a dedicated workstation (Philips HealthCare) with four thresholds: 1.6xSUVmean of background, 1.8xSUVmean of background, SUVmean and SUVmax of the contralateral striatum. The delineation accuracy of different thresholds was visually evaluated and a t-test was used to compare the different VOIs volumes (0.05 significance-level). RESULTS: 50 patients were included (36 previously received surgery). Volume definition based on the striatum SUVmax was significantly smaller compared to other thresholds (2.1 cm3), resulting in inaccurate VOIs at visual inspection in 21/50 patients. No significant differences were highlighted in BTV defined based on 1.6 or 1.8xSUVmean of background (15.7 vs. 12.7 cm3; VOIs accurate in 49/50 and 46/50 patients, respectively). BTV based on striatum SUVmean was significantly smaller compared to the 1.6xSUVmean threshold only in surgically-treated patients (p=0.04), while no significant differences were highlighted compared to the 1.8xSUVmean threshold regardless of the patients' group. CONCLUSIONS: The ESTRO-EANO FET-PET thresholds proved to be interchangeable in patients scanned with [18F]DOPA-PET, while the use of a threshold based on the contralateral-striatum SUVmean provided partially overlapping results prompting further investigation.

Cognitive dysfunction, social behavior disorder, cerebellar ataxia, and atypical brain FDG-PET presentation in spinocerebellar ataxia 17: a case report.

BACKGROUND: Spinocerebellar ataxia 17 (SCA17) is a rare autosomal dominant form of inherited ataxia, caused by heterozygous trinucleotide repeat expansions encoding glutamine in the TATA box-binding protein (TBP) gene. CASE DESCRIPTION: We describe the clinical history, neuropsychological, and neuroimaging findings of a 42-year-old patient who presented for medical attention showing prevalent behavioral and cognitive problems along with progressively worsening gait disturbances. The patient's family history indicated the presence of SCA17 in the maternal lineage. Genetic analysis confirmed a heterozygous 52-CAG pathological expansion repeat in TBP (normal interval, 25-40 CAG. Brain 18-fluorodeoxyglucose positron emission tomography (FDG-PET) showed bilateral hypometabolism in the sensorimotor cortex, with a slight predominance on the right, as well as in the striatal nuclei and thalamic hypermetabolism, a finding similar to what is observed in Huntington's disease. The patient also underwent neuropsychological evaluation, which revealed mild cognitive impairment and difficulties in social interaction and understanding other's emotions (Faux Pas Test and Reading the Mind in the Eyes Test). CONCLUSION: Our report emphasizes the importance of considering SCA17 as a possible diagnosis in patients with a prevalent progressive cognitive and behavioral disorders, even with a pattern of FDG-PET hypometabolism not primarily indicative of this disease.

Focal seizures with impaired awareness as long-term neurological complication of COVID-19: a case report.

We report here the first case of a young individual otherwise healthy, who presented with frequent focal seizures with impaired awareness as a possible long-term complication of severe acute respiratory syndrome coronavirus-2 infection. Seizures were documented by electroencephalography and responded clinically and neuro-physiologically to antiseizure therapy. The patient underwent an extensive investigation including cerebrospinal fluid examination, conventional and quantitative brain magnetic resonance imaging, and 18-FDG positron emission tomography. Beyond the clinical interest, this case contributes to clarify the possible pathways by which SARS-CoV-2 may enter the central nervous system and cause long-term neurological complications.

Comparison of Digital versus Analog 68Ga-PSMA-11 PET/CT Performance in Hormone-Sensitive Prostate Cancer Patients with Early Biochemical Recurrence or Persistence after Radical Treatment.

The aim of this study was to investigate whether the favorable characteristics of novel digital PET/CT (dPET) scanners compared to analog systems (aPET) could translate into an improved disease localization in prostate cancer (PCa) patients with early biochemical recurrence/persistence (BCR/BCP). A retrospective analysis was conducted on 440 consecutive analog (n = 311) or digital (n = 129) 68Ga-PSMA-11 PET/CT scans performed in hormone-sensitive ADT-free PCa patients with early-BCR/BCP (PSA at PET ≤ 2.0 ng/mL), previously treated with radical intent (radical-prostatectomy/radiotherapy). dPET showed a higher positivity rate compared to aPET (48.8% [63/129] vs. 37.3% [116/311], p = 0.03), despite the slightly lower median PSA value of the dPET cohort (0.33 [IQR: 0.26-0.61] vs. 0.55 [IQR: 0.40-0.85] ng/mL, p < 0.01). dPET detection rate was higher in both PSA ranges 0.2-0.5 ng/mL (39.0% [32/82] vs. 25.2% [34/135], p = 0.03) and 0.5-1.0 ng/mL (63.2% [24/38] vs. 40.8% [53/130], p = 0.02), but not for PSA ≥ 1.0 ng/mL. dPET detected a higher per patient median number of pathologic findings (PSMA-RADS ≥ 3) and multi-metastatic cases (>3 lesions) among N1/M1-positive scans (21.7% [10/46] vs. 8.6% [9/105], p = 0.03). Moreover, the proportion of uncertain findings among pathological lesions was significantly lower for dPET than aPET (24.4% [39/160] vs. 38.5% [60/156], p = 0.008). Overall, 68Ga-PSMA-11 dPET showed a better performance compared to aPET, resulting in a higher scan-positivity rate, a higher number of detected pathological lesions, and a lower rate of uncertain findings.

A Systematic Review of Amino Acid PET Imaging in Adult-Type High-Grade Glioma Surgery: A Neurosurgeon's Perspective.

Amino acid PET imaging has been used for a few years in the clinical and surgical management of gliomas with satisfactory results in diagnosis and grading for surgical and radiotherapy planning and to differentiate recurrences. Biological tumor volume (BTV) provides more meaningful information than standard MR imaging alone and often exceeds the boundary of the contrast-enhanced nodule seen in MRI. Since a gross total resection reflects the resection of the contrast-enhanced nodule and the majority of recurrences are at a tumor's margins, an integration of PET imaging during resection could increase PFS and OS. A systematic review of the literature searching for "PET" [All fields] AND "glioma" [All fields] AND "resection" [All fields] was performed in order to investigate the diffusion of integration of PET imaging in surgical practice. Integration in a neuronavigation system and intraoperative use of PET imaging in the primary diagnosis of adult high-grade gliomas were among the criteria for article selection. Only one study has satisfied the inclusion criteria, and a few more (13) have declared to use multimodal imaging techniques with the integration of PET imaging to intentionally perform a biopsy of the PET uptake area. Despite few pieces of evidence, targeting a biologically active area in addition to other tools, which can help intraoperatively the neurosurgeon to increase the amount of resected tumor, has the potential to provide incremental and complementary information in the management of brain gliomas. Since supramaximal resection based on the extent of MRI FLAIR hyperintensity resulted in an advantage in terms of PFS and OS, PET-based biological tumor volume, avoiding new neurological deficits, deserves further investigation.

68Ga-Prostate-Specific Membrane Antigen 11 PET/CT Detects Residual Glioblastoma After Radical Surgery in a Patient With Synchronous Recurrent Prostate Cancer: A Case Report.

Prostate-specific membrane antigen (PSMA) is a transmembrane enzyme also known as folate hydrolase 1 highly expressed by prostate cancer (PCa) cells. However, PSMA overexpression by tumor-associated neovasculature of a variety of solid tumors, including glioblastoma (GBM), has also been proven. This clinical case reports about a 67-year-old man with a history of PCa who underwent radical surgery for GBM and performed a Ga-PSMA-11 PET/CT to restage PCa. PET imaging showed PSMA uptake in GBM residual disease after surgery. This finding suggests a possible role of PSMA inhibitors as diagnostic and therapeutic agents in patients affected by GBM.

Absence of TARDBP gene mutations in an italian series of patients with frontotemporal lobar degeneration.

BACKGROUND/AIM: Recent studies showed that TAR DNA-binding protein 43 (TDP-43), encoded by the TARDBP gene, is a major pathological protein in both sporadic and familial frontotemporal lobar degeneration (FTLD). The aim of this study was to search for mutations of the TARDBP gene in the disease. METHODS: We sequenced the TARDBP gene in 172 unrelated FTLD patients recruited from 2 Italian memory clinics. RESULTS: We identified 3 different variants of the TARDBP gene in 12 FTLD patients. Three patients showed a silent variant, Ala66Ala (c.332T --> C) in exon 2. A novel heterozygous mutation was found in intron 4 (c.543 + 51A --> G) in 1 patient, which is not located at the splicing site. Finally, a c.208C --> T variant in the 3' untranslated region was detected in 8 probands. None of the aforementioned variants were predicted to affect TDP-43. Hence, pathogenic mutations were not identified in any of the FTLD cases. CONCLUSION: Our study, in accord with previous studies in different populations, found no evidence for a major genetic role of the TARDBP gene in FTLD.

Multicenter Semiquantitative Evaluation of (123)I-FP-CIT Brain SPECT.

AIMS: The aims of this study were: (1) to cross-compare data from semiquantitative, software-assisted, and phantom-corrected evaluations of (123)I-ioflupane [(123)I]N-ω-fluoropropyl-2ß-carbomethoxy-3ß-{4-iodophenyl}nortropane FP-CIT brain single-photon emission computed tomography (SPECT) acquired in three centers; (2) to assess the accuracy of semiquantitative evaluation; and (3) to identify the threshold with the best accuracy, sensitivity, and specificity in patients with suspected Parkinsonian Syndrome. MATERIAL AND METHODS: Two-hundred-twenty patients, acquired in three centers, were included. All of them underwent (123)I-FP-CIT brain SPECT. All examinations were analyzed with the freely available software, BasGan, and semiquantitative data were used to predict disease. Analysis was based on the values from the most deteriorated putamen and caudate, normalized for age, and corrected by anthropomorphic phantom data. Receiver operating characteristic (ROC) analysis was performed and areas under the curve (AUC) were estimated. RESULTS: Analysis showed high AUCs (.880, .866, .920, and .882 for each center and multicenter setting). Best thresholds were 1.53 and 1.56 for putamen and caudate, respectively. Thresholds of putamen data showed sensitivity and specificity of 86% and 89%, respectively, in the multicenter setting. Neither sensibility nor specificity showed significant differences among centers. CONCLUSION: A unique, accurate threshold for all centers, with high sensitivity and specificity was identified. Semiquantitative assessment of (123)I-FP-CIT brain SPECT among different centers resulted reliable, accurate, and potentially useful in clinical trials.

Radiation therapy in primary mediastinal B-cell lymphoma with positron emission tomography positivity after rituximab chemotherapy.

PURPOSE: To investigate the role of radiation therapy (RT) in patients affected with primary mediastinal B-cell lymphoma (PMBCL) with residual (18)fluorodeoxyglucose positron emission tomography ((18)FDG-PET)-positive disease after rituximab chemotherapy (R-CT). METHODS AND MATERIALS: Thirty-seven patients treated with R-CT and RT, all with (18)FDG-PET scan at diagnosis and before RT, were included. All (18)FDG-PET scans were reviewed, and responses were classified according to the Deauville 5-point scoring system. Outcomes measures were overall survival (OS) and progression-free survival (PFS), estimated for the whole cohort and for subgroups according to (18)FDG-PET score after R-CT. RESULTS: The median follow-up time was 40.9 months. Three patients were assigned to Deauville score 1 (8.1%), 9 to score 2 (24.3%), 7 to score 3 (19%), 14 to score 4 (37.8%), and 4 to score 5 (10.8%). After RT, all patients with score 3-4 experienced a complete response (CR). Among patients with score 5, 1 was in CR (25%), 2 had persistent positivity (50%), and 1 showed progressive disease (25%). A total of 4 patients experienced progression or relapse: 1 of 33 (3%) with scores 1-4, and 3 of 4 (75%) with score 5. The 3-year OS and PFS of the whole cohort were 89.8% and 88.7%, respectively. OS was significantly different between scores 1-3 and scores 4-5 (100% vs 77% at 3 years, P<.05). Patients with a score of 5 had a significantly worse outcome than did all other patients (OS at 2 years, 33.3% vs 100%). CONCLUSIONS: Approximately 50% of PMBCL patients show residual disease at (18)FDG-PET scan after R-CT. RT is able to convert to CR approximately 85% of these patients, but those with a Deauville score of 5 (10%) appear at high risk of progression and death, and they might be candidates for intensified programs.