Prostate cancer is a leading cause of cancer death in men worldwide. Imaging plays a key role in disease detection and initial staging. Emerging data has shown the superiority of PSMA imaging with PET/CT over conventional imaging for primary diagnoses. Single photon emission computed tomography is more available worldwide, and the imaging agent is low in cost. The aim of this study is to compare the diagnostic accuracy of ^99mTc-EDDA/HYNIC-iPSMA SPECT/CT to ¹⁸F-PSMA-1007 PET/CT in the primary diagnosis of prostate cancer and the impact on clinical staging. Methods: In this prospective controlled study, 18 patients with histologically confirmed prostate cancer with unfavorable intermediate-, high-, and very high-risk characteristics were recruited to undergo ¹⁸F-PSMA-PET/CT and ^99mTc-iPSMA SPECT/CT. The median age of the patients was 71 years old, and the median PSA level was 23.3 ng/mL. Lesions were divided into the prostate, seminal vesicles, lymph nodes, bone, and visceral metastases. Volumetric analysis was also performed between the two imaging modalities and correlated with PSA levels. Results: A total of 257 lesions were detected on ¹⁸F-PSMA-PET/CT: prostate (n = 18), seminal vesicles (n = 12), locoregional lymph nodes (n = 62), non-locoregional (n = 67), bone (n = 90), and visceral (n = 8). Of these, ^99mTc-iPSMA-SPECT/CT detected 229 lesions, while both reviewers detected 100% of the lesions in the prostate (18/18), seminal vesicles (12/12), and visceral (8/8); LN LR (56/62; 90%), NLR (57/67; 85%), and bone (78/90; 86%). There were no statistically significant differences between volumetric parameters (t = −0.02122; p = 0.491596). Conclusions: ^99mTc-iPSMA SPECT/CT is useful in the primary diagnosis of prostate cancer. Despite it showing a slightly lower lesion detection rate compared to ¹⁸F-PSMA PET/CT, it exhibited no impact on clinical staging and, consequently, the initial treatment intention.

Neuroendocrine differentiation of prostate cancer (NEDPC) includes de novo presentation and secondary to epigenetic changes, referred as therapy-induced neuroendocrine prostate cancer (t-NEPC). Molecular imaging with prostate-specific membrane antigen (PSMA) and somatostatin analogues positron emission tomography (PET/CT) in NEDPC have not been validated. ¹⁸F-FDG (fluorodeoxyglucose) PET/CT has numerous limitations in prostate cancer (PCa) and the utility in NEDPC has only been reported in a few series of cases. The objective of this study is to compare the lesions detection rate of the three radiotracers in metastatic t-NEPC patients. (1) Material and Methods: Retrospective evaluation of patients with prostate adenocarcinoma treated with androgen deprivation therapy, chemotherapy, a novel androgen receptor pathway inhibitor or a combination of them and a second tumour biopsy confirming t-NEPC was made. All patients underwent ¹⁸F PSMA-1007, ¹⁸F AlF-NOTA-Octreotide, and ¹⁸F-FDG PET/CT. Evaluation of positive lesions was determined and SUVmax of each radiotracer was estimated and correlated with computer tomography (CT) findings. (2) Results: A total of eight patients were included. The mean time from diagnosis of prostate adenocarcinoma to t-NEPC was 28.2 months, with a mean serum specific prostate antigen (PSA) of 16.6 ng/dl at the time of NEPC diagnosis. All patients were treated with antiandrogen therapy and 87.5% with chemotherapy. A total of 273 lesions were identified by CT from which 182 were detected by ¹⁸F-FDG PET/CT, 174 lesions by ¹⁸F PSMA-1007, and 59 by ¹⁸F AlF-NOTA-Octreotide. An interpatient analysis of the lesions was performed and dual tracer ¹⁸F-FDG PET/CT and ¹⁸F PSMA-1007 PET/CT detected a total of 270/273 lesions (98.9%). (3) Conclusions: NEDPC patients demonstrated wide inter and intrapatient molecular imaging heterogeneity within the three radiotracers. ¹⁸F-FDG detected most lesions in t-NEPC among all radiotracers, especially in visceral sites; ¹⁸F PSMA-1007 detected more bone lesions. ¹⁸F AlF-NOTA-Octreotide showed no significant utility.

Parkinsonian syndromes are considered clinicopathological conditions that are challenging to diagnose. Molecular imaging with [18F]-FDOPA and [18F]-FDG contributes to a more accurate clinical diagnosis by evaluating presynaptic dopaminergic pathways and glucose metabolism, respectively. The aim of this study was to correlate diagnoses made from dual PET/CT with the initial clinical diagnoses, as well as during follow-ups in patients with Parkinsonian syndromes. A secondary objective was to describe the imaging findings. Methods: A total of 150 patients with a clinical diagnosis of neurodegenerative Parkinsonism were evaluated using dual PET/CT. Clinically, 82% were diagnosed with PD, while the remaining 18% had an atypical Parkinsonism. Results: Using dual PET/CT, the most frequent diagnosis was PD in 67% of the patients, with the rest being diagnosed with an atypical Parkinsonism. In an agreement analysis between the initial clinical diagnosis and the imaging diagnosis by dual PET/CT, a concordance of 94.1% (n = 95) was observed for PD. In the remaining patients, the clinical diagnosis differed from that suggested by dual PET/CT, with atypical Parkinsonian syndromes being diagnosed as DLB in 40% (n = 4), PSP in 46.7% (n = 7), MSA-C in 75% (n = 6), MSA-P in 70% (n = 7), and CBD in 66.7% (n = 4). A total of 38.66% (n = 58) of patients were followed up (median follow-up of 27 months), with a Kappa coefficient of 0.591 (p < 0.001), suggesting substantial agreement. Conclusions: Dual FDOPA–FDG PET/CT demonstrated moderate agreement with the initial clinical diagnosis of Parkinsonism and moderate to substantial agreement during follow-up. This dual technique, therefore, stands out in differentiating between types of Parkinsonisms.

Introduction: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative, multisystem disorder. Its clinical presentation typically consists of progressive focal muscle atrophy and weakness. In addition to motor disorders, the association between ALS and cancer has been researched, such as frontotemporal dementia and progressive supranuclear palsy. The diagnosis is based primarily on the clinical history, physical examination, electrodiagnostic tests (with an EMG needle), and neuroimaging, such as MRI and ¹⁸F-FDG PET/CT.Presentation of the case: A 67-year-old male patient was diagnosed with prostate adenocarcinoma with a clinical picture of muscle weakness in the lower limbs that caused falls and was associated with fasciculations in the thighs and arms, alterations in the tone of voice, poor memory, and difficulty articulating words. In the neurological assessment, he described walking supported by a walker with decreased strength in both lower limbs and sensitivity without alterations. The diagnoses of upper and lower motor neuron disease and probable ALS were integrated. Furthermore, the probable coexistence of frontotemporal dementia/disorder (FDD) with ALS was considered. The main findings in the ¹⁸F-FDG PET/CT study was hypometabolism in the cortex of the bilateral motor and premotor areas, the anterior cingulate, both caudate and putamen, a metabolic pattern compatible with ALS, and progressive supranuclear palsy.Conclusion: Through the PET/CT studies, we demonstrated a case in which ALS, prostate cancer and progressive supranuclear palsy coexisted molecularly; it was clinically difficult to diagnose. Molecular imaging has potential in the diagnostic and prognostic evaluation of ALS. It is crucial to identify the disease early and reliably through metabolic patterns that allow us to confirm the disease or differentiate it from other pathologies.

RESUMEN La encefalitis autoinmune es una entidad relativamente nueva que consiste en un proceso inflamatorio del sistema nervioso central mediado por anticuerpos e involucra predominantemente el sistema límbico causado por interacción de anticuerpos en contra de antígenos neuronales específicos. La presentación clínica es variable y la resonancia magnética en conjunto con la detección de anticuerpos antineuronales permiten un diagnóstico oportuno. Presentamos un caso clínico de encefalitis autoinmune con anticuerpos anti-GAD positivos y consideramos los aspectos imagenológicos y clínicos relevantes para su diagnóstico.

Word count: 248 Introduction: Bickerstaff's Encephalitis (BE) is considered a rare immune-mediated disorder, characterized by the clinical triad of ophthalmoplegia, ataxia and impaired consciousness. It falls within the spectrum of anti-GQ1b diseases. Diagnosis uses clinical and laboratory criteria, and imaging techniques allows other diseases to be ruled out. The use of 18F-fluorodeoxyglucose positron emission tomography (PET) in BE has not been extended, so a case with PET follow-up is presented. Presentation of the case: This is a 29-year-old patient, with a history of chronic headache, hypertension and grade III obesity presented 72 hours prior to admission drowsiness, ophthalmoplegia, right peripheral facial palsy, dysarthria, and gait disturbance, flaccid tetra paresis and generalized hyperreflexia. An autoimmune inflammatory disease was suspected. The determination for antiganglioside antibodies (anti GT1a IgG and anti GQ1b IgG) were positive. The diagnosis of Bickerstaff encephalitis was integrated. The main findings in the PET/CT with 18F-FDG study were cortical hypometabolism in occipital region, and cerebellum, and hypermetabolism in the striatum bilaterally, with normalization of the brain metabolism after treatment on the second PET-FDG scan performed after 4 months of onset of the clinical picture. Conclusion: We demonstrate a case of BE by molecular imaging with PET-FDG before and after treatment with normalization of brain metabolism with cognitive improvement. Molecular Imaging has a potential in the diagnostic, and monitoring evaluations of BE. PET (Positron Emission Tomography) could be an earlier marker for neurological conditions as BE and an excellent tool to aid diagnosis, to provide timely treatment and follow-up BE patients.