An Evaluation of Renal Sinus Fat Accumulation Using the Anteroposterior Diameter of the Renal Sinus on a Computed Tomography Axial Image.

Backgrounds and objectives Renal sinus fat (RSF) is an indicator of obesity-related complications. However, the measurement and imaging process are complicated. For a simple measurement of RSF, we focused on the kidney's shape change caused by RSF accumulation. Thus, this study aimed to investigate whether the anteroposterior diameter of the renal sinus (APDRS) on a computed tomography (CT) axial image is useful for evaluating RSF accumulation. Materials and methods The correlation between APDRS and RSF was investigated in 98 outpatients who underwent abdominal CT. In addition, the correlation between APDRS or RSF and obesity indicators (estimated glomerular filtration rate from serum creatinine levels (eGFRcreat), body mass index (BMI), and visceral adipose tissue (VAT)) was also investigated. We classified patients based on the presence or absence of at least one underlying disease (chronic kidney disease (CKD), cardiovascular diseases (CVD), hypertension, and type 2 diabetes (T2D)) and investigated significant differences between the two groups at APDRS and RSF. The intraclass correlation coefficient (ICC) was also calculated for APDRS. Results There was a strong positive correlation between RSF and APDRS (r = 0.802, P < 0.01). The obesity indicators (eGFRcreat, BMI, and VAT) were correlated with RSF and APDRS (P < 0.01). Out of 98 outpatients, 48 had at least one underlying disease. There were statistically significant differences in APDRS and RSF between the patients with and without at least one of the underlying diseases caused by obesity (P < 0.01). The inter-reader ICC for the measurement of the APDRS was 0.98. Conclusions APDRS on a CT axial image may be useful for the evaluation of RSF accumulation.

Tomotherapy: Comparison of Hi-ART, Tomo-HD, and Radixact.

Aim In this study, we compared three generations of tomotherapy (Hi-ART, Tomo-HD, and Radixact). This is to study the difference among tomotherapy systems in terms of dose distribution to planning target volume and organs at risk, and irradiation time.  Materials and methods The treatment planning CT and contour information used were seven cases of rectum cancer pre-operative irradiation. The contour information used was the planning target volume, and the organs at risk were set as the bladder and body. Optimization was conducted at each planning station using the parameters that were actually used in a clinical setting. The prescribed radiation dose was 25 Gy in five fractions and normalized at the isodose line, covering 95% of the planning target volume. Results There were no significant differences in planning target volume among the three models. Meanwhile, Hi-ART had a significantly higher dose than Tomo-HD and Radixact at body D50%. Radixact shortened the irradiation time by approximately 15% compared to Hi-ART/Tomo-HD. Conclusion Planning target volume dose distribution of tomotherapy devices was not different. Radixact required a significantly shorter time than Hi-ART and Tomo-HD.

Transitional phase Gd-EOB-DTPA-enhanced MRI: Visual assessment of hepatic function and fibrosis based on uptake rate of Gd-EOB-DTPA.

PURPOSE: The aim of the study is to investigate the feasibility for hepatic function and fibrosis visual assessment using transitional phase imaging based on the uptake process of Gd-EOB-DTPA. MATERIALS AND METHODS: We retrospectively selected 105 consecutive patients who underwent Gd-EOB-DTPA enhanced MRI examination at 1.5 Tesla for intrahepatic lesion evaluation from June 2020 to June 2022. Data were classified into two groups defined by the signal intensity (SI) difference in the hepatic vein against that of the hepatic parenchyma at transitional phase as follows: High and Iso-SI group: hepatic vein SI equal to or greater than the hepatic parenchymal SI; and Low-SI group: hepatic vein SI lower than hepatic parenchymal SI. We evaluated whether significant differences in ALBI score, FIB-4, APRI and LSR of hepatobiliary phase between two groups. We measured cut-off values between two groups in all items according to receiver operating characteristic analysis. Furthermore, the inter-reader reproducibility of the visual assessment on transitional phase images between two readers was evaluated using the ICC. RESULTS: The visual assessment results were as follows: High and Iso- and Low-SI groups included 48, 57, patients, respectively. Significant differences were observed in ALBI score, FIB-4, APRI and LSR between two groups. The cut-off values of ALBI score, FIB-4, APRI and LSR were -2.69, 2.28, 0.49 and 2.15. ICC of transitional phase image visual assessment between two readers was 0.86. CONCLUSIONS: Hepatic function and fibrosis might be assessed by visual assessment of transitional phase images in Gd-EOB-DTPA enhanced MRI.

Diagnostic accuracy of the attenuation value in abdominal contrast enhanced dynamic multi-detector-row computed tomography for esophageal varices in patients with liver cirrhosis.

PURPOSE: To investigate whether the attenuation value obtained by subtracting the CT value obtained from abdominal dynamic contrast enhanced (ADCE)-MDCT imaging of the equilibrium phase from the value obtained from that of the portal phase in hepatic parenchyma is useful in distinguishing normal liver from liver cirrhosis (LC) and to predict the development of esophageal varices (EVs) in patients with LC. MATERIALS AND METHODS: We assigned 72 outpatients to group A (n = 45; normal liver) and group B (n = 27; LC), who underwent ADCE-MDCT. The attenuation value and CT value of the hepatic parenchymal portal and equilibrium phase were compared, and the correlation between attenuation value and biomarkers (ALB, T-bil, PLT, FIB-4, APRI, and AAR) was investigated. Furthermore, we investigated differences in the attenuation value, FIB-4, APRI, and AAR between the two subgroups of group B [without EVs (group a) and with EVs (group b)]. We performed receiver operating characteristic (ROC) analysis of the attenuation value, FIB-4, APRI, and, AAR for subgroup a vs b and evaluated the diagnostic accuracy. RESULTS: Significant differences were observed between groups A and B in all items. The attenuation value correlated with ALB, T-bil, PLT, FIB-4, and APRI. Only attenuation value showed a significant difference between groups a and b. The best cut-off attenuation value, FIB-4, APRI, and AAR for predicting EVs, according to ROC analysis was 13.4 HU, 6.8, 1.9, and 1.5. CONCLUSIONS: Attenuation value can be useful to quantitatively classify normal liver and LC and to predict EVs in patients with LC.

Usefulness of the frontal lobe bottom and cerebellum tuber vermis line as an alternative clue to set the axial angle parallel to the AC-PC line in I-123 IMP SPECT imaging: a retrospective study.

We aimed to investigate whether the frontal lobe bottom and cerebellum tuber vermis (FLB-CTV) line on brain perfusion scintigraphy, using iodine-123 isopropyl iodoamphetamine single photon emission computed tomography (I-123 IMP SPECT) images, is useful to determine an axial angle parallel to the anterior commissure-posterior commissure (AC-PC) line. We measured the angular differences between the AC-PC line and the FLB-CTV line on midsagittal brain magnetic resonance imaging (MRI) scans of 100 patients. We also evaluated the angular differences of the FLB-CTV line between the IMP SPECT images and the computed tomography for attenuation correction (CTAC) images in the same 100 patients, using a reference line on the CTAC images. Furthermore, the inter-reader reproducibility of the FLB-CTV line measurements on IMP SPECT images of 50 patients between two readers was evaluated using the intra-class correlation coefficient (ICC) and 95% confidence interval (CI). The mean and standard deviation of the angular differences between the AC-PC and FLB-CTV lines on midsagittal brain MRI scans were - 1.24° and 1.14°, respectively. The mean and the standard deviation of the angular differences of the FLB-CTV line in the IMP SPECT and CTAC images were 0.87° and 0.48°, respectively. The ICC of the FLB-CTV line measurements on IMP SPECT images was 0.99 (95% CI 0.98-0.99). We demonstrated that the FLB-CTV line was almost parallel to the AC-PC line and could be reconstructed using IMP SPECT images. The FLB-CTV line can be used as additional evidence to set the axial angle parallel to the AC-PC line.

Investigation of the feasibility of a simple method for verifying the motion of a binary multileaf collimator synchronized with the rotation of the gantry for helical tomotherapy.

In this paper, we suggest a new method for verifying the motion of a binary multileaf collimator (MLC) in helical tomotherapy. For this we used a combination of a cylindrical scintillator and a general-purpose camcorder. The camcorder records the light from the scintillator following photon irradiation, which we use to track the motion of the binary MLC. The purpose of this study is to demonstrate the feasibility of this method as a binary MLC quality assurance (QA) tool. First, the verification was performed using a simple binary MLC pattern with a constant leaf open time; secondly, verification using the binary MLC pattern used in a clinical setting was also performed. Sinograms of simple binary MLC patterns, in which leaves that were open were detected as "open" from the measured light, define the sensitivity which, in this case, was 1.000. On the other hand, the specificity, which gives the fraction of closed leaves detected as "closed", was 0.919. The leaf open error identified by our method was -1.3 ± 7.5%. The 68.6% of observed leaves were performed within ± 3% relative error. The leaf open error was expressed by the relative errors calculated on the sinogram. In the clinical binary MLC pattern, the sensitivity and specificity were 0.994 and 0.997, respectively. The measurement could be performed with -3.4 ± 8.0% leaf open error. The 77.5% of observed leaves were performed within ± 3% relative error. With this method, we can easily verify the motion of the binary MLC, and the measurement unit developed was found to be an effective QA tool.

Variability in bladder volumes of full bladders in definitive radiotherapy for cases of localized prostate cancer.

BACKGROUND AND PURPOSE: To evaluate variation in bladder volume of full bladders in definitive radiotherapy for localized prostate cancer and to investigate potential predictors of increased bladder volume variations. PATIENTS AND METHODS: In 40 patients, the bladder volume was measured with megavoltage computed tomography (MVCT) imaging performed just before irradiation during the administration of the 1st fraction (#1), the 10th fraction (#10), the 20th fraction (#20), and the 30th fraction (#30). Patients were instructed to avoid urinating for 60-90 minutes before the planning CT (pln-CT) scan and before daily irradiation. Patients were also encouraged to drink an unspecified volume of liquid that would result in a clear but tolerable urge to urinate. RESULTS: The population-mean bladder volume (±1SD) was 219 ml (±83 ml) at the planning CT scan (pln-CT), 186 ml (±96 ml) at #1, 149 ml (±73 ml) at #10, 137 ml (±59 ml) at #20, and 136 ml (±60 ml) at #30. The mean intrapatient variation in bladder volume (1 SD relative to the mean bladder volume of each patient) was 38% (range: 10-84%). The bladder volume at the pln-CT was correlated with the intrapatient variance in bladder volume with a correlation coefficient of 0.54 and p <0.001. CONCLUSION: We observed a significant decline in bladder volumes during the course of radiotherapy. The bladder volume at the pln-CT was a significant predictor of increased bladder volume variations.