Comparison between PSMA PET/CT and MRI for Characterizing Hepatocellular carcinoma: A Real-World Study.

Prostate specific membrane antigen (PSMA) is expressed by hepatocellular carcinoma (HCC). PSMA PET/CT has potential as an imaging agent for the detection of HCC including early diagnosis and monitoring for recurrence following surgical resection. This study aims to compare PSMA PET to standard surveillance imaging in the detection of HCC. Patients with suspected or treated HCC were prospectively recruited from a tertiary hospital outpatient clinic. In addition to routine surveillance imaging as recommended by the multidisciplinary team, a PSMA PET/CT was performed. Imaging and clinical characteristics were compared over a follow-up period of up to 12 months. In a cohort of 19 patients with known HCC or suspected recurrent HCC, PSMA PET/CT had similar efficacy to MRI for the detection of HCC, with a sensitivity of 91% and a specificity of 70% and sensitivity of 87% and a specificity of 73% for PSMA PET/CT and MRI, respectively. PSMA PET/CT had a higher negative predictive value of 90%. In this relatively large single centre study, PSMA is shown to have promising equivalence in performance and its role should be further evaluated in multi-centre prospective trials.

Incidental prostate-specific membrane antigen-avid meningioma detected on 68Ga-prostate-specific membrane antigen PET/CT.

A 70-year-old gentleman with a history of Gleason score 7 (3 + 4) prostate adenocarcinoma was treated with radical prostatectomy with clear surgical margins. Postoperatively his prostate specific antigen was undetectable. However, his prostate specific antigen was slowly rising and he was referred for a 68Galium-Prostate Specific Membrane Antigen (PSMA) PET/CT scan. Findings were suggestive of local prostatic cancer recurrence with no evidence of nodal or distant metastasis. An incidental PSMA avid focus was noted in the left frontal lobe, inseparable from the left frontal bone laterally. Subsequent MRI findings were consistent with meningioma. Meningioma is the most common primary brain tumor and may be a cause of false positive prostate cancer metastasis due to 68Ga-PSMA uptake.

68Ga-Prostate-Specific Membrane Antigen Solitary Base of Skull Prostate Adenocarcinoma Metastasis.

A 74-year-old man with prostate adenocarcinoma (Gleason 7) was referred for Ga-prostate-specific membrane antigen (PSMA-HBED-CC) PET/CT scan for staging. Findings confirmed the prostate malignancy and demonstrated a solitary metastasis in the left skull base, with no evidence of regional or distant metastasis elsewhere. Solitary base of the skull metastasis may be subtle and easily overlooked, highlighting the need for thorough evaluation of the region.

Solitary Femoral Nodal Metastasis Identified With 68Ga-Prostate-Specific Membrane Antigen PET/CT.

ABSTRACT: A 66-year-old man was referred for a 68Ga-prostate-specific membrane antigen (PSMA) PET/CT scan for primary staging of Gleason 8 prostatic adenocarcinoma. The PET/CT images confirmed PSMA activity in the bilateral prostatic apex in keeping with the known malignancy. An intensely PSMA-avid focus was also noted in a nonenlarged right femoral lymph node with no evidence of PSMA-avid metastatic disease elsewhere. Subsequent core biopsy and histopathology confirmed a solitary metastatic focus of prostatic adenocarcinoma in a right femoral lymph node.

Solitary 68Ga-PSMA-Avid Proximal Tibial Prostatic Adenocarcinoma Metastasis Mimicking Enthesopathy.

A 76-year-old man with previously treated prostatic adenocarcinoma (Gleason 8) was referred for a Ga-prostate-specific membrane antigen PET/CT scan due to a rising serum PSA level. An intensely PSMA-avid focus was demonstrated in the left proximal tibia with no evidence of local recurrence or metastatic disease elsewhere. This was diagnosed and managed as enthesopathy. A Tc-MDP bone scan with SPECT/CT performed 9 months later confirmed an intensely osteoblastic mixed lytic/sclerotic metastasis at the left proximal tibia.

68Ga-Prostate-Specific Membrane Antigen Uptake in Dissecting Abdominal Aortic Aneurysm.

An 81-year-old man with prostate adenocarcinoma (Gleason 4 + 3 = 7) treated with brachytherapy and intermittent androgen deprivation therapy was referred for serial Ga-prostate-specific membrane antigen (PSMA-HBED-CC) PET/CT scans for rising prostate-specific antigen. Findings were suggestive of local prostatic recurrence and nodal metastases. An incidental PSMA-avid focus was noted in the anterior wall of an infrarenal aortic aneurysm, with a contrast-enhanced hyperdense region surrounded by a semilunar hypodense region anteriorly, consistent with enlarging dissecting thrombus. Increased PSMA avidity in atherosclerotic hypertensive lesions may relate to active plaque instability, indicating a need for further evaluation.

False-Positive 18F-FDG PET/CT Uptake in Unilateral Lactation.

A 31-year-old woman (7 months postpartum and lactating) with multiple sclerotic bone lesions was referred for an 18F-FDG PET/CT scan for characterization. The scan demonstrated unilateral diffuse intense FDG uptake corresponding to dense soft tissue in the right breast, likely related to secretory hyperplasia. On further questioning, it was made apparent that she had only been breastfeeding from the right breast. While the left breast also demonstrated dense soft tissue to a lesser degree, no significant FDG uptake was seen. The sclerotic bone lesions were not FDG avid, likely due to a separate non-FDG avid benign condition or bony metastases from a non-FDG avid primary malignancy. This was reinforced by the fact that subsequent investigations including serial bilateral breast ultrasound and percutaneous biopsy demonstrated no definite evidence of malignancy in the bilateral breasts. The histopathology findings of an open surgical biopsy of sclerotic lesions in the left posterior ilium were also nonspecific, favouring bone dysplasia with no evidence of malignancy.