The association of quantitative PSMA PET parameters with pathologic ISUP grade: an international multicenter analysis.

PURPOSE: To assess if PSMA PET quantitative parameters are associated with pathologic ISUP grade group (GG) and upgrading/downgrading. METHODS: PCa patients undergoing radical prostatectomy with or without pelvic lymph node dissection staged with preoperative PSMA PET at seven referral centres worldwide were evaluated. PSMA PET parameters which included SUVmax, PSMAvolume, and total PSMA accumulation (PSMAtotal) were collected. Multivariable logistic regression evaluated the association between PSMA PET quantified parameters and surgical ISUP GG. Decision-tree analysis was performed to identify discriminative thresholds for all three parameters related to the five ISUP GGs The ROC-derived AUC was used to determine whether the inclusion of PSMA quantified parameters improved the ability of multivariable models to predict ISUP GG ≥ 4. RESULTS: A total of 605 patients were included. Overall, 2%, 37%, 37%, 10% and 13% patients had pathologic ISUP GG1, 2, 3, 4, and 5, respectively. At multivariable analyses, all three parameters SUVmax, PSMAvolume and PSMAtotal were associated with GG ≥ 4 at surgical pathology after accounting for PSA and clinical T stage based on DRE, hospital and radioligand (all p < 0.05). Addition of all three parameters significantly improved the discrimination of clinical models in predicting GG ≥ 4 from 68% (95%CI 63 - 74) to 74% (95%CI 69 - 79) for SUVmax, 72% (95%CI 67 - 76) for PSMAvolume, 74% (70 - 79) for PSMAtotal and 75% (95%CI 71 - 80) when all parameters were included (all p < 0.05). Decision-tree analysis resulted in thresholds that discriminate between GG (SUVmax 0-6.5, 6.5-15, 15-28, > 28, PSMAvol 0-2, 2-9, 9-20 and > 20 and PSMAtotal 0-12, 12-98 and > 98). PSMAvolume was significantly associated with GG upgrading (OR 1.03 95%CI 1.01 - 1.05). In patients with biopsy GG1-3, PSMAvolume ≥ 2 was significantly associated with higher odds for upgrading to ISUP GG ≥ 4, compared to PSMAvolume < 2 (OR 6.36, 95%CI 1.47 - 27.6). CONCLUSION: Quantitative PSMA PET parameters are associated with surgical ISUP GG and upgrading. We propose clinically relevant thresholds of these parameters which can improve in PCa risk stratification in daily clinical practice.

Diagnosis of Seronegative Rheumatoid Arthritis by 68 Ga-FAPI PET/CT.

Early diagnosis of rheumatoid arthritis with the initiation of disease-modifying antirheumatic drugs is important to prevent future disability. Seronegative rheumatoid arthritis lacks the classical immunological markers, thus imposing clinical diagnostic difficulty. In this case, we reported 68 Ga-FAPI PET/CT findings of seronegative rheumatoid arthritis in a 60-year-old lady. This case illustrates how 68 Ga-FAPI PET/CT aids in the diagnosis of seronegative rheumatoid arthritis.

Current status of PSMA PET imaging in prostate cancer.

The past decade has witnessed the rising popularity and acceptance of molecular definitions on disease management. Prostate-specific membrane antigen (PSMA), in light of its molecular nature and cytokinetic properties, has rapidly become the target for development of a variety of functional tracers for PET/CT evaluation of prostate cancer. The most commonly used PSMA-binding analog is 68 Ga-labeled PSMA-11, which is now widely applied in both research and clinical settings. Literature data in the recent years have been enriched by a number of meta-analyses and systemic reviews on the evolving role of PSMA PET in primary diagnosis, staging, detection of biochemical recurrence after primary cancer treatment, identification, and significance of oligometastasis, as well as in restaging and treatment monitoring. Being a highly sensitive and reasonably specific molecular tracer, PSMA-binding analogs have a high potential to possess the majority of imaging characteristics required for a variety of management decisions in prostate malignancy.

Massive pericardial effusion: A rare and easily missed finding in myocardial perfusion scintigraphy.

A 72-year-old gentleman underwent myocardial perfusion scintigraphy (MPS) for sinus tachycardia of unknown cause. Baseline electrocardiography (ECG) showed sinus tachycardia and electrical alternans. Thallium-201 stress-redistribution MPS was performed with dipyridamole stress. On the raw projection images, a photopenic "halo" was noted surrounding the heart. Reconstructed slices showed small left ventricle with no obvious perfusion defect. Review of single-photon emission computed tomography/computed tomography images showed suspected large pericardial effusion. The patient was admitted and Echocardiography showed significant circumferential pericardial effusion with early tamponade effect. Subsequent bedside pericardiocentesis aspirated 800 ml blood-stained fluid and the cytology yielded metastatic adenocarcinoma with features suggestive of pulmonary primary. Pericardial effusion is a rare finding in MPS. Finding of a "halo" around the heart should raise suspicion on the presence of pericardial effusion and confirmatory investigation such as ECG may be warranted.