Spectral CT with monochromatic imaging and metal artifacts reduction software for artifacts reduction of ¹²⁵I radioactive seeds in liver brachytherapy

Peritumoral abnormalities on dynamic-enhanced CT after brachytherapy for hepatic malignancies: local progression or benign changes?

Objectives

To determine if dynamic CT can differentiate local progression from radioactive seed-induced peritumoral reaction (RSIPR) after brachytherapy with iodine-125 radioactive seeds (BIRS) for advanced hepatic malignancies.

Methods

Enhanced CT images of seed-implanted lesions between 2006 and 2018 were retrospectively evaluated. Hounsfield units of peritumoral parenchyma were measured and assessed quantitatively. The classification, conversion, consequences, and serological indicators during follow-up were recorded and quantified. Statistical differences were analyzed using a Pearson χ² test.

Results

RSIPR was observed in 201 of 290 (69.3%) lesions (161 patients; median age, 55 years; range, 26–79 years), while local progression occurred in 53 lesions. The low density of local progression was much lower than that of RSIPR (p < 0.001), and the former did not exhibit iso-/high density in the portal or equilibrium phase. Ring-like enhancement in progressive lesions was also quite different from RSIPR. Local progression rate was lower for lesions with RSIPR than for those without RSIPR (14.9% vs 25.8%; p = 0.03), and their doses were different (397.2 Gy vs 120.3 Gy, p < 0.001).

Conclusions

Radioactive seed-induced peritumoral reaction has characteristic manifestations on CT images, which is associated with a higher dose of lesions and lower local progression rate. Notably, the enhancement pattern of local progression was distinct from RSIPR and was clearly distinguishable on dynamic-enhanced CT.

Key Points

• Radioactive seed-induced peritumoral reaction after brachytherapy with¹²⁵I seeds for liver malignancies has characteristic manifestations on CT images, which is associated with a higher dose of lesions (397.2 Gy vs 120.3 Gy, p < 0.001), as a focal radiation injury.

• Lesions with RSIPR were less likely to develop local progression, while those without RSIPR had a higher rate of local progression (14.9% vs 25.8%; p = 0.03).

• The enhancement pattern of local progression after brachytherapy was distinct from radioactive seed-induced peritumoral reaction and was clearly distinguishable on dynamic-enhanced CT.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-022-09074-x.

Lobaplatin promotes 125I-induced apoptosis and inhibition of proliferation in hepatocellular carcinoma by upregulating PERK-eIF2α-ATF4-CHOP pathway

We investigated the mechanism underlying the effect of a combination treatment of ¹²⁵I radioactive seed implantation and lobaplatin (LBP) in hepatocellular carcinoma. The effects of administration of HCC cells and subcutaneous tumor model of mice with different doses of ¹²⁵I or a sensitizing concentration of LBP alone, or in combination, on cellular apoptosis and proliferation were analyzed and it was confirmed that LBP promotes ¹²⁵I-induced apoptosis and inhibition of proliferation of HCC. Furthermore, isobaric tag for relative and absolute quantification labeling analyses suggested that ¹²⁵I promoted the apoptosis and inhibition of proliferation of HCC cells by upregulating the expression of PERK-eIF2α-ATF4-CHOP pathway, a well-known apoptosis-related pathway. Moreover, LBP was found to boost the ¹²⁵I-induced upregulation of this pathway and increase the apoptosis. Our data indicate that LBP promotes the apoptotic and anti-proliferative effects of ¹²⁵I and provide a firm foundation for better clinical application of this combination therapy.

Ultrasound-guided percutaneous microwave ablation vs. surgical resection for thoracoabdominal wall implants from hepatocellular carcinoma: intermediate-term results

OBJECTIVE

The aims of this study were to compare the clinical outcomes between ultrasound (US)-guided percutaneous microwave ablation (MWA) and surgical resection (SR) in patients with thoracoabdominal wall implants from hepatocellular carcinom (HCC) and to identify the prognostic factors associated with the two treatment methods.

MATERIALS AND METHODS

A total of 47 patients (mean age, 56.7 ± 15.9 years, range, 18-78 years; 34 men and 13 women) with 61 thoracoabdominal wall HCC seeding were included from April 2007 to May 2017. Twenty-five patients underwent US-guided MWA and 22 patients underwent SR. Survival, recurrence and liver function were compared between the two groups. Effect of changes in key parameters (i.e. overall survival (OS), disease-free survival (DFS) and local tumour reoccurrence-free (LTRF)) was statistically analysed with the log-rank test. Univariate and multivariate analyses were performed on several clinicopathological variables to identify factors affecting long-term outcome and recurrence.

RESULTS

The OS, DFS and LTRF after MWA were comparable to those of SR (p =0.493, p = 0.578 and p =0.270, respectively). Estimated 5-year overall survival rates were 63% after MWA and 48.1% after SR; for disease-free survival, estimated 5-year rates were 67.5% after MWA and 48.8% after SR; estimated 24-month LTRF rates were 71.3% after MWA and 87.8% after SR. The MWA group had less surgical time (p = <0.001), estimated blood loss (p = <0.001) and post-operative hospitalisation (p = 0.032) and cost (p = 0.015). Multivariate analysis showed remnant intrahepatic tumour (p =0.007), Child Pugh grade (p = 0.009) and metastasis (p= <0.001), were predictors for survival rate.

CONCLUSIONS

Ultrasound-guided percutaneous MWA is a safe and effective treatment method for metastatic HCC on the thoracoabdominal wall with similar outcomes to SR. Residual intrahepatic HCC, Child Pugh grade and distant metastasis are predictors for survival.

Reduction of metal artifacts due to dental hardware in computed tomography angiography: assessment of the utility of model-based iterative reconstruction

PURPOSE

The aim of this study is to assess the value of adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) for reduction of metal artifacts due to dental hardware in carotid CT angiography (CTA).

METHODS

Thirty-seven patients with dental hardware who underwent carotid CTA were included. CTA was performed with a GE Discovery CT750 HD scanner and reconstructed with filtered back projection (FBP), ASIR, and MBIR. We measured the standard deviation at the cervical segment of the internal carotid artery that was affected most by dental metal artifacts (SD₁) and the standard deviation at the common carotid artery that was not affected by the artifact (SD₂). We calculated the artifact index (AI) as follows: AI = [(SD₁)2 - (SD₂)2]1/2 and compared each AI for FBP, ASIR, and MBIR. Visual assessment of the internal carotid artery was also performed by two neuroradiologists using a five-point scale for each axial and reconstructed sagittal image. The inter-observer agreement was analyzed using weighted kappa analysis.

RESULTS

MBIR significantly improved AI compared with FBP and ASIR (p < 0.001, each). We found no significant difference in AI between FBP and ASIR (p = 0.502). The visual score of MBIR was significantly better than those of FBP and ASIR (p < 0.001, each), whereas the scores of ASIR were the same as those of FBP. Kappa values indicated good inter-observer agreements in all reconstructed images (0.747-0.778).

CONCLUSIONS

MBIR resulted in a significant reduction in artifact from dental hardware in carotid CTA.

Metal implants on CT: comparison of iterative reconstruction algorithms for reduction of metal artifacts with single energy and spectral CT scanning in a phantom model

PURPOSE

To assess single energy metal artifact reduction (SEMAR) and spectral energy metal artifact reduction (MARS) algorithms in reducing artifacts generated by different metal implants.

MATERIALS AND METHOD

Phantom was scanned with and without SEMAR (Aquilion One, Toshiba) and MARS (Discovery CT750 HD, GE), with various metal implants. Images were evaluated objectively by measuring standard deviation in regions of interests and subjectively by two independent reviewers grading on a scale of 0 (no artifact) to 4 (severe artifact). Reviewers also graded new artifacts introduced by metal artifact reduction algorithms.

RESULTS

SEMAR and MARS significantly decreased variability of the density measurement adjacent to the metal implant, with median SD (standard deviation of density measurement) of 52.1 HU without SEMAR, vs. 12.3 HU with SEMAR, p < 0.001. Median SD without MARS of 63.1 HU decreased to 25.9 HU with MARS, p < 0.001. Median SD with SEMAR is significantly lower than median SD with MARS (p = 0.0011). SEMAR improved subjective image quality with reduction in overall artifacts grading from 3.2 ± 0.7 to 1.4 ± 0.9, p < 0.001. Improvement of overall image quality by MARS has not reached statistical significance (3.2 ± 0.6 to 2.6 ± 0.8, p = 0.088). There was a significant introduction of artifacts introduced by metal artifact reduction algorithm for MARS with 2.4 ± 1.0, but minimal with SEMAR 0.4 ± 0.7, p < 0.001.

CONCLUSION

CT iterative reconstruction algorithms with single and spectral energy are both effective in reduction of metal artifacts. Single energy-based algorithm provides better overall image quality than spectral CT-based algorithm. Spectral metal artifact reduction algorithm introduces mild to moderate artifacts in the far field.

Combination of 125I brachytherapy and chemotherapy for unresectable recurrent breast cancer: A retrospective control study

Recurrent breast cancer remains an incurable malignancy and cannot be removed by surgery in the majority of cases. This study aimed to explore the feasibility and efficacy of the combination of I brachytherapy and chemotherapy for the treatment of unresectable recurrent breast cancer. Patients with unresectable recurrent breast cancer treated between January 2011 and December 2014 with a combination of I brachytherapy and capecitabine or gemcitabine were evaluated and outcomes were compared with those of women treated with capecitabine or gemcitabine in conventional dose as a monotherapy. Of 61 patients evaluated, 28 received the combination treatment and 33 received capecitabine or gemcitabine monotherapy. The combination of I brachytherapy and chemotherapy resulted in a significant improvement in progression-free survival versus capecitabine or gemcitabine monotherapy (median, 17.8 vs 11.4 months; hazard ratio [HR], 0.44; 95% confidence interval [CI], 0.23-0.84; P = 0.013). The objective response rate (ORR) was significantly higher with the combination (82.1%) than with monotherapy (54.5%; P = 0.022), and the rate of pain relief was higher in the combination arm (100% vs 73.6%; P = 0.038). There was no significant improvement for overall survival (median, 30.1 vs 27.2 months; HR, 0.82; 95% CI, 0.47-1.44; P = 0.496). There were no serious complications detected during the follow-up period, any grade toxicities were comparable between treatment arms. In conclusion, the combination of I brachytherapy and second-line chemotherapy is superior to chemotherapy alone and is an effective and safe therapy for unresectable recurrent breast cancer. However, further investigation and much larger scale randomized controlled trials with long-term follow-up are needed.

Single-energy metal artifact reduction in postimplant computed tomography for I-125 prostate brachytherapy: Impact on seed identification

PURPOSE

To evaluate the effectiveness of the single-energy metal artifact reduction (SEMAR) technique for improving the accuracy of I-125 seed identification in postimplant computed tomography (CT) after prostate brachytherapy.

METHODS AND MATERIALS

Postimplant CT images of 40 patients treated with I-125 prostate brachytherapy were acquired. For all patients, 2 data sets were reconstructed, 1 with SEMAR algorithms (SEMAR image), and the other without SEMAR algorithms (non-SEMAR image). Seed locations are automatically detected by the automatic seed finder tool, and their locations were compared between the SEMAR and non-SEMAR images. Dosimetric parameters using seed locations as detected were compared.

RESULTS

The true-positive fraction of properly detected seeds on the SEMAR image as determined from a reference seed distribution defined by one investigator was significantly higher than the true-positive fraction on the non-SEMAR image (p = 0.011). The variabilities in D₉₀ (p = 0.001), V₁₀₀ (p = 0.007), and V₁₅₀ (p = 0.007) were significantly reduced for seed location on the SEMAR image as compared with non-SEMAR image.

CONCLUSIONS

Prostate postimplant CT with SEMAR improved the accuracy of seed localization and postimplant dosimetric parameters.