Lessons from a 3-Year Review of PSMA PET-CT in a Tertiary Setting: Can We Fine Tune Referral Criteria by Identifying Factors Predicting Positivity and Negativity?

AIM OF THE STUDY: To draw inferences from a retrospective evaluation of PSMA PET CT scans performed for the evaluation of biochemical recurrence. MATERIAL AND METHODS: A retrospective analysis of 295 PSMA PET CT scans spanning 3 years between 2020 and 2022 was undertaken. RESULTS: Of 295 PET CT scans, 179 were positive, 66 were negative and 50 had indeterminate findings. In the positive group, 67 had radical prostatectomy and PSMA avid lesions were seen most commonly in pelvic lymph nodes. The remaining 112 positive scans were in the non-radical prostatectomy group; 25 had recurrence only in the prostate, 17 had recurrence involving the prostate bed; 28 had no recurrence in the prostate gland, while 42 had recurrence in the prostate as well as in extra-prostatic sites. Overall, in the non-prostatectomy group, 75% of the population was harboring a PSMA avid lesion in the prostate gland while in the remaining 25% of the population, recurrence did not involve the prostate gland. The majority of indeterminate findings were seen in small pelvic or retroperitoneal lymph nodes or skeletal regions (ribs/others) and in nine patients indeterminate focus was seen in the prostate bed only. Follow-up PSMA PET CT was helpful in prior indeterminate findings and unexplained PSA rise. CONCLUSION: A higher recurrence in the prostate bed while evaluating biochemical recurrence prompts the following: question: should prostatectomy be offered more proactively? Follow-up PSMA PET CT is helpful for indeterminate findings; a PSA rise of 0.7 ng/mL in 6 months can result in positive PSMA PET CT while negative scans can be seen up to a 2 ng/mL PSA rise in 6 months.

A Review on the Usage of Bone Single-Photon Emission Computed Tomography/Computed Tomography in Detecting Skeletal Metastases in the Post-COVID-19 Era: Is it Time to Ditch Planar and Single-Photon Emission Computed Tomography only Gamma Camera Systems?

Planar whole-body bone scanning (WBS) is widely used to evaluate skeletal lesions seen in cancer and noncancer cases. Frequently, degenerative, or other benign bony changes may give rise to indeterminate lesions that mimic bone metastases. In the post-COVID-19 era, there is an evolutionary phase that puts importance on global development and adaptability, which encompasses to include nuclear medicine practices worldwide. Single-photon emission computed tomography/computed tomography (SPECT/CT) can be used to improve the characterization of these lesions and help to resolve the diagnostic conundrum while reducing the need for patients to undergo multiple different examinations at various imaging departments. The fusion of SPECT and CT allows morphological characterization of functional abnormality detected by focal tracer uptake on planar scintigraphy, which provides a one-stop center imaging in nuclear medicine departments. The objective of this study was to review the diagnostic accuracy of SPECT/CT in diagnosing bone metastases in a variety of oncology and nononcology cases and to determine the feasibility of performing bone SPECT/CT in all suspected cancer cases, including cases of bone infection instead of planar imaging alone. The utilization of hybrid SPECT/CT in indeterminate bone lesions detected on planar WBS can significantly increase the diagnostic confidence and accuracy of image interpretation. Recognition of patterns of disease identified using hybrid imaging can improve the management of patients with potentially lower costs in the long term. Currently, hybrid SPECT/CT machines are becoming a norm in nuclear medicine departments, thus potentially making single planar application machines obsolete in the near future. We hypothesize that in the interest of providing a meaningful interpretation of isotope bone scans, the default protocol should involve the option of acquiring SPECT/CT images rather than relying on whole-body scans only. Departments choosing to upgrade existing equipment or those choosing to invest in only one gamma camera should proactively opt for hybrid SPECT/CT systems.

Bone single-photon emission computed tomography/computed tomography in cancer care in the past decade: a systematic review and meta-analysis as well as recommendations for further work.

Skeletal whole-body scintigraphy (WBS), although widely used as a sensitive tool for detecting metastatic bone disease in oncology cases, has relatively low specificity. Indeterminate bone lesions (IBLs) detected by WBS cause a diagnostic dilemma, which hampers further management plans. In the advent of hybrid imaging, single-photon emission computed tomography/computed tomography (SPECT/CT) has been gaining popularity as a tool to improve the characterisation of IBLs detected by WBS. As yet, there has not been a systematic review to objectively evaluate the diagnostic capabilities of SPECT/CT in this area. We conducted a systematic review of relevant electronic databases up to 30 August 2020. The outcomes of interest were the reporting of SPECT/CT to identify benign and malignant IBLs and the calculation of the sensitivity and specificity of the index test, based on histopathological examination or clinical and imaging follow-up as the reference standard. After the risk of bias and eligibility assessment, 12 articles were identified and synthesised in the meta-analysis. The pooled sensitivity and specificity of SPECT/CT for diagnosing IBLs are 93.0% [95% confidence interval (CI) 0.91-0.95] and 96.0% (95% CI 0.94-0.97), respectively. There was heterogeneity of the articles due to variable imaging protocols, duration of follow-up and scoring methods for interpreting the SPECT/CT results. The heterogeneity poses a challenge for accurate interpretation of the true diagnostic capability of SPECT/CT. In conclusion, targeted SPECT/CT improves the specificity of diagnosing bone metastases, but efforts need to be made to standardise the thresholds for SPECT/CT, methodology, as well as harmonising the reporting and interpretation criteria. We also make some recommendations for future works.

A study of homicidal deaths in medico-legal autopsies at UMMC, Kuala Lumpur.

The main aim of this study was to determine the causes and epidemiological aspects of homicidal deaths. Data were collected on 217 homicidal victims from the total number of 2762 autopsies performed in UMMC, Kuala Lumpur over a five-year period, from year 1999 to 2003. There were 194 male victims and 23 female victims. The largest number of victims (63.6%) were in the age group of 20-39 years. Indians comprised the maximum proportion of victims (28.1%). Approximately 71.9% of victims came from the semiskilled and unskilled group. A majority of victims were married (47%). Injuries caused by sharp weapons (41%) were the most common cause of death, followed by blunt trauma and firearm injuries.