Role of non-contrast CT component of prostate-specific membrane antigen PET/CT scan in the detection of peripheral zone prostate cancer.

OBJECTIVE: The aim of this study was to look for feasibility of non-contrast CT (NCCT) in detecting peripheral zone prostate cancer (PCa). METHODS: A retrospective analysis included 50 biopsy-proven PCa patients between April 2019 and March 2022 who underwent staging whole body prostate-specific membrane antigen (PSMA)/CT prior to treatment. The control subjects were 50 randomly selected adult male patients who underwent PET/CT for non-prostate malignancy during the same time period. Two readers independently calculated the Hounsfield unit (HU) of normal peripheral zone, central zone, and corresponding PSMA avid focus in cases. RESULTS: No significant difference was seen in the mean HU value of normal peripheral zone between cases and controls. Significant difference in the mean HU was seen between the PSMA avid focus in cases (40.1 ± 6.2) and normal peripheral zone of cases (28.2 ± 7.0) and controls (27.7 ± 5.8). No significant difference was found between the mean HU values of high-grade PCa and non-high-grade PCa. Receiver operating characteristic (ROC) curve analysis revealed a mean HU cut-off of ≥35 for detecting PCa with a sensitivity and specificity of 86% and 90%, respectively, between cases and controls (AUC 0.88). CONCLUSION: Detection of clinically significant PCa is possible on routinely performed NCCT scans. Radiologists should routinely look for and convey these findings to facilitate further work-up and early detection of PCa. ADVANCES IN KNOWLEDGE: Our study adds to the knowledge that NCCT scans performed for unrelated indications can serve as a screening tool for clinically significant PCa.

Imaging update in spinal tuberculosis.

Tuberculosis is ancient disease known to mankind. Diagnosis and management of spinal tuberculosis has immensely improved in last few decades. Imaging, particularly MRI, plays important role in diagnosis of spinal tuberculosis and its complications. Four common imaging patterns of spinal tuberculosis include paradiscal type, central type, Anterior subligamentous type, and posterior type. Imaging also plays important role in differentiation of spinal tuberculosis from its mimics, particularly pyogenic spondylitis, and metastasis. Radiological interventions, such as CT guided vertebral biopsy, and percutaneous drainage of cold abscess, are commonly used in management of spinal tuberculosis. Monitoring of therapeutic response is often based on clinical evaluation and imaging. MRI is most common imaging modality used. Signs of healing include bony ankylosis, resolution of marrow edema, decrease in contrast enhancement, and fatty change with in bone marrow. PET CT is recently evaluated for response assessment with promising results. This review summarizes pathophysiology, clinical presentation, imaging features, radiological interventions, and response assessment in spinal tuberculosis.