Value of Magnetic Resonance Imaging for Skeletal Bone Age Assessment in Healthy Male Children.

BACKGROUND: Skeletal bone age assessment for medical reasons is usually performed by conventional x-ray with use of ionizing radiation. Few pilot studies have shown the possible use of magnetic resonance imaging (MRI). PURPOSE: To comprehensively evaluate feasibility and value of MRI for skeletal bone age (SBA) assessment in healthy male children. MATERIALS AND METHODS: In this prospective cross-sectional study, 63 male soccer athletes with mean age of 12.35 ± 1.1 years were examined. All participants underwent 3.0 Tesla MRI with coronal T1-weighted turbo spin echo (TSE), coronal proton density (PD)-weighted turbo spin echo (TSE), and T1-weighted three-dimensional (3D) volume interpolated breath-hold examination (VIBE) sequence. Subsequently, SBA was assessed by 3 independent blinded radiologists with different levels of experience using the common Greulich-Pyle (GP) atlas and the Tanner-Whitehouse (TW2) method. RESULTS: In a mean total acquisition time of 5:04 ± 0:47 min, MR image quality was sufficient in all cases. MRI appraisal was significantly faster ( P < 0.0001) by GP with mean duration of 1:22 ± 0:08 min vs. 7:39 ± 0:28 min by TW. SBA assessment by GP resulted in mean age of 12.8 ± 1.2 years, by TW 13.0 ± 1.4 years. Interrater reliabilities were excellent for both GP (ICC = 0.912 (95% confidence interval [CI] = 0.868-0.944) and TW (ICC = 0.988 (95% CI = 0.980-0.992) and showed statistical significance ( P < 0.001). Subdivided, for GP, ICCs were 0.822 (95% CI = 0.680-0.907) and 0.843 (95% CI = 0.713-0.919) in Under 12 and Under 14 group. For TW, ICCs were 0.978 (95% CI = 0.958-0.989) in Under 12 and 0.979 (95% CI = 0.961-0.989) in Under 14 group. CONCLUSION: MRI is a clinically feasible, rapidly evaluable method to assess skeletal bone age of healthy male children. Using the Greulich-Pyle (GP) atlas or the Tanner-Whitehouse (TW2) method, reliable results are obtained independent of the radiologist's experience level.

Microwave Ablation (MWA) of Pulmonary Neoplasms: Clinical Performance of High-Frequency MWA With Spatial Energy Control Versus Conventional Low-Frequency MWA.

OBJECTIVE. The objective of our study was to evaluate the clinical performance of a new high-frequency (HF) microwave ablation (MWA) technology with spatial energy control for treatment of lung malignancies in comparison with a conventional low-frequency (LF) MWA technology. MATERIALS AND METHODS. In this retrospective study, 59 consecutive patients (mean age, 58.9 ± 12.6 [SD] years) were treated in 71 sessions using HF spatial-energy-control MWA. Parameters collected were technical success and efficacy, tumor diameter, tumor and ablation volumes, ablation time, output energy, complication rate, 90-day mortality, local tumor progression (LTP), ablative margin size, and ablation zone sphericity. Results were compared with the same parameters retrospectively collected from the last 71 conventional LF-MWA sessions. This group consisted of 56 patients (mean age, 60.3 ± 10.8 years). Statistical comparisons were performed using the Wilcoxon-Mann-Whitney test. RESULTS. Technical success was 98.6% for both technologies; technical efficacy was 97.2% for HF spatial-energy-control MWA and 95.8% for LF-MWA. The 90-day mortality rate was 5.1% (3/59) in the HF spatial-energy-control MWA group and 5.4% (3/56) in the LF-MWA group; for both groups, there were zero intraprocedural deaths. The median ablation time was 8.0 minutes for HF spatial-energy-control MWA and 10.0 minutes for LF-MWA (p < 0.0001). Complications were recorded in 21.1% (15/71) of HF spatial-energy-control MWA sessions and in 31.0% (22/71) of LF-MWA sessions (p = 0.182); of these complications, 4.2% (3/71) were major complications in the HF spatial-energy-control MWA group, and 9.9% (7/71) were major complications in the LF-MWA group. The median deviation from ideal sphericity (1.0) was 0.195 in the HF spatial-energy-control MWA group versus 0.376 in the LF-MWA group (p < 0.0001). Absolute minimal ablative margins per ablation were 7.5 ± 3.6 mm (mean ± SD) in the HF spatial-energy-control MWA group versus 4.2 ± 3.0 mm in the LF-MWA group (p < 0.0001). In the HF spatial-energy-control MWA group, LTP at 12 months was 6.5% (4/62). LTP at 12 months in the LF-MWA group was 12.5% (7/56). Differences in LTP rate (p = 0.137) and time point (p = 0.833) were not significant. CONCLUSION. HF spatial-energy-control MWA technology and conventional LFMWA technology are safe and effective for the treatment of lung malignancies independent of the MWA system used. However, HF spatial-energy-control MWA as an HF and high-energy MWA technique achieves ablation zones that are closer to an ideal sphere and achieves larger ablative margins than LF-MWA (p < 0.0001).

Microwave ablation of pancreatic tumors.

OBJECTIVES: To evaluate the clinical performance of percutaneous microwave ablation (MWA) for treatment of locally-advanced-pancreatic-cancer (LAPC). MATERIAL AND METHODS: Twenty-two MWA sessions (August 2015-March 2017) in 20 patients with primary pancreatic cancer (13 men, 7 women, mean-age: 59.9 ± 8.6 years, range: 46-73 years), who had given informed consent, were retrospectively evaluated. All procedures were performed percutaneously under CT-guidance using the same high-frequency (2.45-GHz) MWA device. Tumor location and diameter, ablation diameter and volume, roundness, duration, technical success and efficacy, output energy, complications, and local tumor progression defined as a tumor focus connected to the edge of a previously technically efficient ablation zone were collected. RESULTS: Seventeen pancreatic malignant tumors (77.3%) were located in the pancreatic head and five (22.7%) in the pancreatic tail. Initial Mean Tumor Diameter was 30 ± 6 mm. Technical success and efficacy were idem (100%). No major complications occurred. Two patients (9.1%) showed minor complications of severe local pain related to MWA. Post-ablation diameter was on average 34.4 ± 5.8 mm. Mean ablation volume was 7.8 ± 3.8 cm³. The mean transverse roundness index was 0.74 ± 0.14. Mean ablation time was 2.6 ± 0.96 min. The mean applied energy per treatment was 9627 ± 3953 J. Local tumor progression was documented in one case (10%) of the 10/22 available three-month follow-up imaging studies. CONCLUSION: High-frequency (2.45 GHz) microwave ablation (MWA) for treatment of unresectable and non-metastatic locally-advanced-pancreatic-cancer (LAPC) shows promising results regarding feasibility and safety of percutaneous approach after short-term follow-up and should be further evaluated.

Evaluation of microwave ablation of liver malignancy with enabled constant spatial energy control to achieve a predictable spherical ablation zone.

OBJECTIVES: To evaluate the clinical performance of a new microwave ablation (MWA) system with enabled constant spatial energy control (ECSEC) to achieve spherical ablation zones in the treatment of liver malignancies. MATERIALS AND METHODS: In this retrospective study, 56 hepatic tumours in 48 patients (23 men, 25 women; mean age: 59.6 years) were treated using a new high-frequency MWA-system with ECSEC. Parameters evaluated were technical success, technical efficacy, tumour diameter, tumour and ablation volume, complication rate, 90-day mortality, local tumour progression (LTP) at the 12-month follow-up, ablative margin and ablation zone sphericity. These parameters were compared using the Kruskal-Wallis test with the same parameters collected retrospectively from cohorts of patients treated with conventional high-frequency (HF) MWA (n = 20) or low-frequency (LF) MWA (n = 20). RESULTS: Technical success was achieved in all interventions. The technical efficacy was 100% (ECSEC) vs. 100% (LF-MWA) vs. 95% (HF-MWA). There were no intra-procedural deaths or major complications. Minor complications occurred in 3.57% (2/56), 0% (0/20) and 0% (0/20) of the patients, respectively. The one-year mortality rate was 16.1% (9/56), 15% (3/20) and 10% (2/20), respectively. The LTP was 3.57% (2/56), 5% (1/20) and 5% (1/20), respectively. The median deviation from ideal sphericity (1.0) was 0.135 (ECSEC) vs. 0.344 (LF-MWA) vs. 0.314 (HF-MWA) (p < 0.001). The absolute minimal ablative margin was 8.1 vs. 2.3 vs. 3.1 mm (p < 0.001). CONCLUSIONS: Microwave ablation of liver malignancies is a safe and efficient treatment independent of the system used. Hepatic MWA with ECSEC achieves significantly more spherical ablation zones and higher minimal ablative margins.