Image quality and diagnostic performance of free-breathing diffusion-weighted imaging for hepatocellular carcinoma

To retrospectively evaluate the diagnostic performance of free-breathing diffusion-weighted imaging (FB-DWI) with modified imaging parameter settings for detecting hepatocellular carcinomas (HCCs). METHODSFifty-one patients at risk for HCC were scanned with both FB-DWI and respiratory-triggered DWI with the navigator echo respiratory-triggering technique (RT-DWI). Qualitatively, the sharpness of the liver contour, the image noise and the chemical shift artifacts on each DWI with b-values of 1000 s/mm2 were independently evaluated by three radiologists using 4-point scoring. We compared the image quality scores of each observer between the two DWI methods, using the Wilcoxon signed-rank test. Quantitatively, we compared the signal-to-noise ratios (SNRs) of the liver parenchyma and lesion-to-nonlesion contrast-to-noise ratios (CNRs) after measuring the signal intensity on each DWI with a b-factor of 1000 s/mm2. The average SNRs and CNRs between the two DWI methods were compared by the paired t-test. The detectability of HCC on each DWI was also analyzed by three radiologists. The detectability provided by the two DWI methods was compared using McNemar’s test. RESULTSFor all observers, the averaged image quality scores of FB-DWI were: Sharpness of the liver contour [observer (Obs)-1, 3.08 ± 0.81; Obs-2, 2.98 ± 0.73; Obs-3, 3.54 ± 0.75], those of the distortion (Obs-1, 2.94 ± 0.50; Obs-2, 2.71 ± 0.70; Obs-3, 3.27 ± 0.53), and the chemical shift artifacts (Obs-1, 3.38 ± 0.60; Obs-2, 3.15 ± 1.07; Obs-3, 3.21 ± 0.85). The averaged image quality scores of RT-DWI were: Sharpness of the liver contour (Obs-1, 2.33 ± 0.65; Obs-2, 2.37 ± 0.74; Obs-3, 2.75 ± 0.81), distortion (Obs-1, 2.81 ± 0.56; Obs-2, 2.25 ± 0.74; Obs-3, 2.96 ± 0.71), and the chemical shift artifacts (Obs-1, 2.92 ± 0.59; Obs-2, 2.21 ± 0.85; Obs-3, 2.77 ± 1.08). All image quality scores of FB-DWI were significantly higher than those of RT-DWI (P < 0.05). The average SNR of the normal liver parenchyma by FB-DWI (11.0 ± 4.8) was not significantly different from that shown by RT-DWI (11.0 ± 5.0); nor were the lesion-to-nonlesion CNRs significantly different (FB-DWI, 21.4 ± 17.7; RT-DWI, 20.1 ± 15.1). For all three observers, the detectability of FB-DWI (Obs-1, 43.6%; Obs-2, 53.6%; and Obs-3, 45.0%) was significantly higher than that of RT-DWI (Obs-1, 29.1%; Obs-2, 43.6%; and Obs-3, 34.5%) (P < 0.05). CONCLUSIONFB-DWI showed better image quality and higher detectability of HCC compared to RT-DWI, without significantly reducing the SNRs of the liver parenchyma and lesion-to-nonlesion CNRs.

CT-guided radiofrequency ablation of osteoid osteoma in the long bones of the lower extremity

AIM:To present our initial experience with computed tomography guided radiofrequency ablation(RFA) of osteoid osteoma(OO) in our institution.METHODS:RFA was performed on eight patients(5 males and 3 females) with clinically and radiologically diagnosed OO(femoral neck,n = 4;femoral diaphysis,n = 2;tibial diaphysis,n = 1;fibular diaphysis,n = 1).Ablation was performed using an electrode with a 10-mm exposed tip for a total of 4-6 min at a targeted temperature of 90 degrees Celsius.No cooling system was used.The intervention was accepted as technically successful if the tip of the electrode could be placed within the center of the nidus.We defined clinical success as a disappearance within 2 wk after treatment of symptoms that had manifested at presentation.RESULTS:All procedures were technically successful.No major or immediate complications were observed.Clinical success was achieved in six of eight patients in the first procedure.A second procedure was performed for two patients who had recurrent or continued pain,and one of these cases was successfully treated.The overall rate of success was 87.5%(7/8).No complication was observed.CONCLUSION:Our preliminary results indicate a favorable success rate and no complications and are compatible with the previous reports of RFA of OO.

Detecting hepatic nodules and identifying feeding arteries of hepatocellular carcinoma: efficacy of cone-beam computed tomography in transcatheter arterial chemoembolization

Aim:To evaluate the effectiveness of using cone-beam computed tomography(CBCT)in transcatheter arterial chemoembolization(TACE)to detect hapatocellular carcinoma(HCC)nodules and their feeding arteries.Methods:Twenty-four patients with HCCs who underwent TACE using CBCT in addition to conventional digital subtraction angiography(DSA)were enrolled.After both conventional DSA and CBCT through the hepatic artery were acquired,TACE were performed.The nodules were defined as an HCC when dense accumulation of iodized oil was found within the nodule on CT obtained 2 weeks after the TACE.The number of detected nodules and identified feeding arteries,and their correlations with anatomical locations were assessed.Results:A total of 39 HCC nodules(tumor diameter,7-40 mm;mean,17.4±7.9 mm)were detected.Thirty-one nodules were detected by DSA alone but 8 nodules were additionally detected by adding CBCT to DSA.There were 53 feeding arteries associated with the 39 HCC nodules.Among these arteries,21 were identified by DSA alone;however,47 were identified by combining CBCT with DSA.Additional feeding arteries,especially for the nodules located at the right and caudate lobes,were identified by CBCT.On the other hand,there was no difference in detection of nodules between the anatomical locations by CBCT.Conclusion:The use of CBCT in addition to DSA offers potential for increasing the number of detected nodules,and the number of their feeding arteries at the right and caudate lobes.CBCT might improve the quality of TACE procedure for HCC than DSA alone.