Technetium Tc-99m albumin aggregated kit

The standardized uptake value (SUV) can be measured by single-photon emission computed tomography with computed tomography (SPECT/CT) to provide a quantitative assessment; however, it has not been utilized in lung perfusion imaging (LPI). Since 99mTc MAA is primarily trapped in the lungs, we hypothesized that the SUV normalized to lung volume using CT attenuation correction scans (SUVLV) might offer a more reliable evaluation than the conventional SUV normalized to body weight (SUVBW).

This single-center retrospective study included 58 patients (39 derivation cohorts: 25 patients with chronic thromboembolic pulmonary hypertension (CTEPH) and 14 controls; 19 validation cohorts). SPECT/CT-LPI and right heart catheterization were performed at baseline, initial follow-up, and after completing BPA in the derivation cohort. The lung volume fractions below optimal SUV thresholds that optimally correlated with mean pulmonary arterial pressure (mPAP) were investigated. The diagnostic performance of SUVLV was evaluated to predict mPAP >20 mmHg in the validation cohort.

Mean SUVLV remained consistent (0.88–0.90, P=0.565) across populations and treatment stages, whereas mean SUVBW varied significantly (17.8–25.8, P<0.001). Lung volume fraction with SUVLV ≤0.7 exhibited a strong correlation with mPAP (r=0.632, P<0.001) and decreased progressively with successful BPA and mPAP improvement. In the validation cohort, a cutoff value of lung volume fraction of 50.1% with SUVLV≤0.7 demonstrated 100% sensitivity and specificity for predicting mPAP >20 mmHg.

SUVLV is a reliable quantitative measure for SPECT/CT-LPI compared with SUVBW and may enhance intrapatient and interpatient assessments of disease severity and treatment response in CTEPH.

Craniopharyngioma is a rare, benign intracranial tumour that can present with solid, cystic, or mixed solid-cystic characteristics. This case report aims to discuss the follow up assessment of our patient after one year of the irradiation therapy for craniopharyngioma. A 43-year-old male who has underlying refractory cystic craniopharyngioma requiring two-weekly aspirations, complicated with visual impairment and panhypopituitarism, was referred to our department for intra-cavitary irradiation therapy. Initial diagnostic assessment with Tc-99m MAA followed by dose calculation using the Backlund formula were conducted prior to the therapy. The patient received 6.22 mCi (230.14 MBq) of Ytrrium-90 citrate colloid via the Ommaya reservoir to deliver a radiation dose of 300 Gy to the tumour. Positive outcomes were observed as signified by the reduction on the aspirated cystic frequency and volume, tumour volume, improvement on the visual function and stable hormonal level. Despite the complications, the intra-cavitary irradiation therapy has demonstrated a significant and valuable therapeutic option for our patient in the management of refractory cystic craniopharyngioma.