OBJECTIVE: To determine the effect of reduced abdominal compression in prone position on ascending colonic movement during supine-to-prone positional change during CT colonography (CTC). MATERIALS AND METHODS: Eighteen consecutive patients who had undergone prone CTC scanning with cushion blocks placed under the chest and hip/thigh to reduce abdominal compression and had confirmed sessile polyps > or = 6 mm in the well-distended, straight, mid-ascending colon, were included. Radial location along the ascending colonic luminal circumference (degrees) was measured for 24 polyps and 54 colonic teniae on supine and prone CTC images. The supine-to-prone change ranging between -180degrees and +180degrees (- and + for internal and external colonic rotations, respectively), was determined. In addition, possible causes of any ascending colonic rotations were explored. RESULTS: Abdominal compression during prone CTC scanning completely disappeared with the use of cushion blocks in 17 of 18 patients. However, some degrees of ascending colonic rotation were still observed, with the radial location changes of -22degrees to 61degrees (median, 13.9degrees) for the polyps and similar degrees for teniae. Fifty-four percent and 56% of polyps and teniae, respectively, showed changes > 10degrees. The radial location change of the polyps was significantly associated with the degree of anterior shift of the small bowel and mesentery (r = 0.722, p < 0.001) and the degree of posterior displacement of the ascending colon (r = 0.566, p = 0.004) during supine-to-prone positional change. CONCLUSION: Ascending colonic rotation upon supine-to-prone positional change during CTC, mostly in the form of external rotation, is not eliminated by removing abdominal compression in prone position.
Aged ; Colon/*pathology/*radiography ; Colonic Polyps/*radiography ; Colonography, Computed Tomographic/*methods ; Female ; Humans ; Male ; Middle Aged ; Movement ; Prone Position/*physiology ; Retrospective Studies ; Rotation

Perirectal cystic lesions are rare entities, for which only a relatively few research publications are available. These lesions are heterogeneous in nature and can range from benign lesions to malignant lesions; thus, they are sometimes difficult to differentiate. Some studies have reported on retrorectal or presacral cystic lesions, but to our knowledge, there have been only a few reports on perirectal cystic lesions. Cystic lesions arise from the retrorectal space as well as the rectal lumen or adjacent organ, and they should be differentiated based on their characteristics and anatomic location. Thus, we comprehensively studied diseases with a cystic component around the rectum, which are perirectal cystic lesions. A clinical challenge with perirectal cystic lesions is that it is sometimes difficult to distinguish malignant lesions from benign lesions and is thus difficult to determine the extent for surgical excision. We thus attempted to identify benign and malignant imaging features of perirectal cystic lesions.
Abdomen ; Magnetic Resonance Imaging ; Rectum

Objective: Adequate methods of combining T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) to assess complete response (CR) to chemoradiotherapy (CRT) for rectal cancer are obscure. We aimed to determine an algorithm for combining T2WI and DWI to optimally suggest CR on MRI using visual assessment. Materials and Methods: We included 376 patients (male:female, 256:120; mean age ± standard deviation, 59.7 ± 11.1 years) who had undergone long-course CRT for rectal cancer and both pre- and post-CRT high-resolution rectal MRI during 2017– 2018. Two experienced radiologists independently evaluated whether a tumor signal was absent, representing CR, on both post-CRT T2WI and DWI, and whether the pre-treatment DWI showed homogeneous hyperintensity throughout the lesion. Algorithms for combining T2WI and DWI were as follows: ‘AND,’ if both showed CR; ‘OR,’ if any one showed CR; and ‘conditional OR,’ if T2WI showed CR or DWI showed CR after the pre-treatment DWI showed homogeneous hyperintensity. Their efficacies for diagnosing pathologic CR (pCR) were determined in comparison with T2WI alone. Results: Sixty-nine patients (18.4%) had pCR. AND had a lower sensitivity without statistical significance (vs. 62.3% [43/69]; 59.4% [41/69], p = 0.500) and a significantly higher specificity (vs. 87.0% [267/307]; 90.2% [277/307], p = 0.002) than those of T2WI. Both OR and conditional OR combinations resulted in a large increase in sensitivity (vs. 62.3% [43/69]; 81.2% [56/69], p < 0.001; and 73.9% [51/69], p = 0.008, respectively) and a large decrease in specificity (vs. 87.0% [267/307]; 57.0% [175/307], p < 0.001; and 69.1% [212/307], p < 0.001, respectively) as compared with T2WI, ultimately creating additional false interpretations of CR more frequently than additional identification of patients with pCR. Conclusion AND combination of T2WI and DWI is an appropriate strategy for suggesting CR using visual assessment of MRI after CRT for rectal cancer.

Objective: Adequate methods of combining T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) to assess complete response (CR) to chemoradiotherapy (CRT) for rectal cancer are obscure. We aimed to determine an algorithm for combining T2WI and DWI to optimally suggest CR on MRI using visual assessment. Materials and Methods: We included 376 patients (male:female, 256:120; mean age ± standard deviation, 59.7 ± 11.1 years) who had undergone long-course CRT for rectal cancer and both pre- and post-CRT high-resolution rectal MRI during 2017– 2018. Two experienced radiologists independently evaluated whether a tumor signal was absent, representing CR, on both post-CRT T2WI and DWI, and whether the pre-treatment DWI showed homogeneous hyperintensity throughout the lesion. Algorithms for combining T2WI and DWI were as follows: ‘AND,’ if both showed CR; ‘OR,’ if any one showed CR; and ‘conditional OR,’ if T2WI showed CR or DWI showed CR after the pre-treatment DWI showed homogeneous hyperintensity. Their efficacies for diagnosing pathologic CR (pCR) were determined in comparison with T2WI alone. Results: Sixty-nine patients (18.4%) had pCR. AND had a lower sensitivity without statistical significance (vs. 62.3% [43/69]; 59.4% [41/69], p = 0.500) and a significantly higher specificity (vs. 87.0% [267/307]; 90.2% [277/307], p = 0.002) than those of T2WI. Both OR and conditional OR combinations resulted in a large increase in sensitivity (vs. 62.3% [43/69]; 81.2% [56/69], p < 0.001; and 73.9% [51/69], p = 0.008, respectively) and a large decrease in specificity (vs. 87.0% [267/307]; 57.0% [175/307], p < 0.001; and 69.1% [212/307], p < 0.001, respectively) as compared with T2WI, ultimately creating additional false interpretations of CR more frequently than additional identification of patients with pCR. Conclusion AND combination of T2WI and DWI is an appropriate strategy for suggesting CR using visual assessment of MRI after CRT for rectal cancer.

BACKGROUND: little is known about the mechanisms responsible for ventricular tachycardia during myocardial ischemia and reperfusion. The purpose of this study was to evaluate the effects of the autonomic nervous system on ventricular tachycardia in dogs. METHODS: Four groups of eight dogs were studied. The control group had intact autonomic neural innervation:the stellectomy group had bilateral transection of stellate ganglia:the vagotomy group had bilateral transection of cervical vagi; and the autonomic denervation group underwent bilateral transection of stellate ganglia and cervical vagi. Open-chest dogs anesthetized with ketamine were studied in 3 sequential steps: denervation, ischemia, and reperfusion stage. At the end of each step, we estimated effective refractory period (ERP) at four sites : the apex of non-ischemic area, the base of non-ischemic area, the apex of ischemic area, and the base of ischemic area. We observed early afterdepolarization (EAD) through recording monophasic action potential on the ischemic epicardium during ischemia and reperfusion stages. RESULTS: In ischemia stage, deltaERPs(ERPmax.-ERPmin.) were significantly prolonged, compared to deltaERPs at denervation stage, and deltaERPs of the vagotomy group tended to be prolonged to 60 minutes after myocardial ischemia, as compared to those of the stellectomy group and the autonomic denervation group. The incidence of ventricular tachycardia during ischemia presented a significant increase in the vagotomy group, compared to the control group. However, there was no difference in incidence of ventricular tachycardia between the stellectomy group and the control group. deltaERP at the group with the occurrence of ventricular tachycardia were significantly prolonged , compared to the other group without the occurrence of ventricular tachycardia. In terms of the incidence of EAD, there was no difference between the groups and it was not associated with ventricular tachycardia. deltaERP was significantly decreased to 30 minutes after reperfusion, at which point there was no significant difference between the groups. There was no correlation between EAD and ventricular tachycardia. However, deltaERP with ventricular tachycardia indicated much more significant increase than deltaERP without ventricular tachycardia. CONCLUSIONS: Sympathetic nerve may be related to prolongation of deltaERP and incidence of ventricular tachycardia in the ischemic period. However, EAD is not related to ventricular tachycardia during ischemia and reperfusion. These findings suggest that the major mechanism of ventricular tachycardia may be a reentry in ischemia and reperfusion period.
Action Potentials ; Animals ; Autonomic Denervation* ; Autonomic Nervous System ; Denervation ; Dogs ; Heart* ; Incidence ; Ischemia* ; Ketamine ; Myocardial Ischemia ; Pericardium ; Reperfusion* ; Stellate Ganglion ; Tachycardia* ; Tachycardia, Ventricular ; Vagotomy

PURPOSE: The triad of chest pain, normal coronary arteries and a positive stress test has been called microvascular angina. The link between coronary flow reserve(CFR) and Duke treadmill score(DTS) in patients with microvascular angina remains elusive. METHODS: We studied 108 subjects (M:F=8:60, mean age 54+/-9 yrs) with chest pain and normal coronary angiogram. Exercise treadmill test(ETT) was performed by Bruces protocol and the equation for calculating DTS was DTS=xercise time- (5xST deviation)-(4x exercise angina), with 0=one, 1=onlimiting, 2=exercise-limiting. The coronary flow velocity at diastole(PDV) using Transesophageal echocardiography (TEE) was obtained from the proximal left anterior descending coronary artery and coronary flow reserve(CFR) was calculated as the ratio of hyperemic PDV after the intravenous infusion of dipyridamole(0.56 mg/kg) to baseline PDV. RESULTS: 1) CFR was 3.04+/-0.45 in group with negative ETT and 2.19+/-0.62 in group with positive ETT(p<0.001). 2) CFR was 1.51+/-0.31 in high-risk group with a score of <-10, 2.39+/-0.63 in moderate-risk group with scores from -10 to + and 3.04+/-0.43 in low-risk group with a score of > or =+ on DTS(p< 0.001 versus low-risk, respectively). 3) DTS was significantly related to CFR (r=.704, p<0.001). CONCLUSION: The composite DTS is closely related to CFR using TEE and might be a useful tool that can help clinicians determine the severity of ischemia and evaluate the efficacy of treatment in patients with microvascular angina.
Chest Pain ; Coronary Vessels ; Echocardiography, Transesophageal* ; Exercise Test ; Humans ; Infusions, Intravenous ; Ischemia ; Microvascular Angina*

Although cleft lip and palate are one of the most common craniofacial malformation, little is still known about the mechanism of the palate formation. Retinoic acid (RA) is known a teratogen, and cleft palate is induced by retinoic acid administration in the secondary palate formation stage. Many growth factors and their receptors are involved in the formation of the secondary palate. Here, we investigated the expression of PDGFR-alpha, and PDGFR-beta during palatogenesis after retinoid acid administration in mice by RT-PCR and immunohistochemistry. At E15.5, the opposing palatal shelves fused with one another in the control group, but the palatal shelves were not elevated and cleft palate was induced in the RA-treated group. In RT-PCR, PDGFR-beta was downregulated during palatogenesis after RA administration. In immunohistochemical experiment, PDGFR-alpha and PDGFR-beta were reduced in RA-induced group. Taken together, we suggest that PDGF receptors may be molecules involved in palate formation.
Animals ; Cleft Lip ; Cleft Palate ; Immunohistochemistry ; Intercellular Signaling Peptides and Proteins ; Mice ; Palate ; Receptors, Platelet-Derived Growth Factor* ; Tretinoin*

Purpose: This study was aimed to investigate the value of quantitative ultrasound (US) parameters from radiofrequency (RF) data analysis for assessing hepatic steatosis, using controlled attenuation parameter (CAP)-based steatosis grades as the reference standard. Methods: We analyzed 243 participants with both B-mode liver US with RF data acquisition and CAP measurements. On B-mode US images, hepatic steatosis was visually scored (0/1/2/3, none/mild/moderate/severe), and the hepatorenal index (HRI) was calculated. From the RF data analysis, the tissue scatter-distribution imaging parameter (TSI-p) and tissue attenuation imaging parameter (TAI-p) of the liver parenchyma were measured. US parameters were correlated with CAP-based steatosis grades (S0/1/2/3, none/mild/moderate/severe) and their diagnostic performance was evaluated using receiver operating characteristic (ROC) curve analysis. Multivariate linear regression analysis was performed to identify determinants of TSI-p and TAI-p. Results: Participants were classified as having S0 (n=152), S1 (n=54), S2 (n=14), and S3 (n=23) on CAP measurements. TSI-p and TAI-p were significantly correlated with steatosis grades (ρ =0.593 and ρ=-0.617, P<0.001 for both). For predicting ≥S1, ≥S2, and S3, the areas under the ROC curves (AUCs) of TSI-p were 0.827/0.914/0.917; TAI-p, 0.844/0.914/0.909; visual scores, 0.659/0.778/0.794; and HRI, 0.629/0.751/0.759, respectively. TSI-p and TAI-p had significantly higher AUCs than did visual scores or HRI for ≥S1 or ≥S2 (P≤0.003). In the multivariate analysis, the transient elastography-based fibrosis grade (P=0.034) and steatosis grade (P<0.001) were independent determinants of TSI-p, while steatosis grade (P<0.001) was an independent determinant of TAI-p. Conclusion TSI-p and TAI-p derived from US RF data may be useful for detecting hepatic steatosis and assessing its severity.

Purpose: The accurate detection and quantification of hepatic steatosis using a noninvasive method are important for the management of nonalcoholic fatty liver disease. We performed a systematic review and meta-analysis of the accuracy of the ultrasound-measured attenuation coefficient (AC) in the evaluation of hepatic steatosis. Methods: The PubMed, Embase, and Cochrane databases were searched for prospective studies reporting the diagnostic accuracy of AC for assessing hepatic steatosis. The meta-analytic pooled sensitivity and specificity of AC for any grade of steatosis (S≥1) and advanced steatosis (S≥2) were estimated using a bivariate random-effects model. Meta-regression analysis was conducted to investigate the causes of heterogeneity among studies. Results: Thirteen studies including 1,509 patients were identified. The pooled sensitivity and specificity of AC for S≥1 were 76% (95% confidence interval [CI], 73% to 80%; I2=43%) and 84% (95% CI, 77% to 89%; I2=74%), respectively, while for S≥2 they were 87% (95% CI, 83% to 91%; I2=0%) and 79% (95% CI, 75% to 83%; I2=59%), respectively. Study heterogeneity was associated with body mass index (BMI) and the prevalence of steatosis or significant fibrosis. Conclusion AC can be clinically useful for assessing hepatic steatosis, with good overall diagnostic performance. The data reported in the published literature differed according to BMI and the prevalence of steatosis or significant fibrosis, and careful interpretation with consideration of these factors might be needed.