Background: The existence of anatomical variants, including a high division of popliteal artery branching and hypoplastic branching in the tibial artery, are present in ~10% of infrapopliteal arteries. In Type III variants in particular, one or both of the anterior tibial and posterior tibial arteries are hypoplastic or aplastic, and it is difficult for diagnostic angiography to distinguish usual anatomical patterns in a Type III variant with chronic total occlusion (CTO). Therefore, it is important to be aware of anatomical variations in the infrapopliteal artery prior to revascularization in cases of critical limb ischemia (CLI). The ability to identify the presence of variants using duplex ultrasound scanning (DUS) in advance is expected to be useful for revascularization.

Purposes: The present study aimed to investigate ultrasound findings of Type III variants that can be detected by DUS, and the association between Type III variants and CLI.

Subjects and Methods: Between January 2016 and October 2017, a total of 603 limbs in 353 patients (238 men and 115 women, mean age 72±11 years) with suspected lower limb ischemia were enrolled in the present study. The patients were divided into two groups according to the presence or absence of CLI. The rate of Type III variants were compared between these groups. Additionally, the patients were divided into two groups according to the presence of the Type III variant or usual anatomical pattern, excluding cases with lower extremity arterial occlusive/stenosis. The ultrasound findings, including the angle of direction of the distal tibial arteries, vessel diameter, and diameter ratio of the tibial arteries were compared between these groups.

Results: Of the total 603 limbs in 353 patients, the Type III variant was present in 31 limbs of 26 patients (5.1%), which were classified as Type III-A (2.3%; 14/603), Type III-B (2.4%; 15/603), and Type III-C (0.2%; 2/603). The rate of the Type III variant was significantly higher (10.9% vs. 3.1%, p＜0.001) in the CLI group. There were significant differences between the Type III and usual pattern in the angles of the distal tibial arteries, vessel diameter, and diameter ratio of the tibial artery.

Conclusion: The rate of the Type III variant was higher in patients with CLI as compared with those without CLI. With CTO of the lower limb artery, diagnostic angiography is often difficult to evaluate vessels sufficiently; however, DUS is useful for the distinction between usual anatomical patterns and the Type III variant. Lower extremity arterial DUS is useful for the detection of infrapopliteal variants in CLI.

Purpose: We examined the characteristics of carotid ultrasound findings in patients receiving cervical radiotherapy and compared with control cases with combined risk factors.

Subjects and Methods: Fifteen patients (age, 71±7 years, 12 males) with history of cervical radiation among those evaluated by carotid artery ultrasonography from April 2012 to March 2014 at our hospital were included in the study. Background clinical data on duration after radiotherapy, original disease, hypertension, dyslipidemia, diabetes, smoking, and cerebral infarction were investigated. Maximum intima-media thickness (IMT), plaque properties, stenosis, and plaque score were determined by carotid ultrasonography. The propensity score-matching method was used to determine control cases and adjust the influence of confounding factors for comparison with patients who received cervical radiation.

Results and Discussion: Six (40%) of 15 patients developed cerebral infarction after cervical radiotherapy, and more than 5 years had passed since radiation therapy. Plaque properties by carotid ultrasonography in patients receiving cervical radiotherapy had noticeable clinically vulnerable plaques such as ulcerative, low-echoic, and cautionable plaques, and significant stenosis were found frequently. By carotid ultrasonography, the IMT increase was observed in several carotid artery sites including the common carotid artery, which is rarely affected by arteriosclerosis, compared with the control cases determined by the propensity score-matching method. These findings suggested that radiation therapy was associated with changes in carotid pulse echogenic properties.

Conclusion: Carotid ultrasound findings after cervical radiation therapy were examined to characterize the range of changes including plaque formation and stenosis in bilateral carotid arteries, especially the carotid arteries. Changes were observed in the carotid arteries due to radiotherapy, instability, and stenosis of the vessel wall may progress over time, and regular follow-up by ultrasonic examination is necessary in these patients.

Background: Atrial septal defect (ASD) in adult patients could be overlooked by transthoracic echocardiography (TTE), particularly when ASD size and left-to-right shunt rates are small. However, it is unclear how sensitivity to detect ASD with TTE differs with ASD size.

Methods: We retrospectively enrolled 4,507 consecutive adult patients who underwent TEE. Of these patients, 86 were diagnosed with ASD (63±11 years, 47 females and 36 males). ASD patients were divided into 3 groups according to ASD size: Group L (ASD size＞10 mm, n＝37), Group M (ASD size 5 to 10 mm, n＝11), and Group S (ASD size＜5 mm, n＝38). We compared the sensitivities of ASD detection by TTE prior to TEE and right ventricular (RV) chamber geometries among the three groups.

Results: In total, ASD detection rate by TTE was 50.0% (43 patients). TTE was able to detect ASD in 4 patients in group S (10.5%), 5 patients (45.5%) in group M, and 34 patients (91.9%) in group L. Basal and mid RV linear dimensions index obtained by conventional four-chamber view were larger in Group L compared to those in Group S (Basal: 25.2±4.6 mm/m² vs. 21.5±4.2 mm/m², p＜0.01, Mid: 24.5±5.5 mm/m² vs. 18.1±3.6 mm/m², p＜0.01). Group L had larger indexed proximal and distal RVOT dimensions (Proximal: 22.1±4.8 mm/m², Distal: 19.6±3.4 mm/m²) compared to those in Group M (Proximal: 18.0±3.5 mm/m², p＜0.01, Distal: 16.1±1.6 mm/m², p＜0.05) and group S (Proximal: 16.9±3.0 mm/m², p＜0.05, Distal: 15.9±1.9 mm/m², p＜0.01).

Conclusions: The sensitivity of large ASD detection by TTE is satisfactory but that of small ASD detection by TTE is much lower. The lack of RV volume overload could explain the lower detection rate of small ASD by TTE.

Purpose: We aimed to identify factors complicating diagnostic ultrasound of acute pancreatitis (AP) with the goal of improving the rate of correct diagnosis.

Subjects and Methods: This observational study included 124 patients (98 males and 26 females; age, 56±15 years) among 134 adult subjects with AP who were evaluated at our hospital between December 2009 and October 2016. Ten patients who were examined by computed tomography (CT) prior to ultrasound were excluded. The remaining 124 patients with AP were retrospectively classified into “failed,” “weak,” and “strong” groups based on ultrasound findings. Pancreatic echogenicity and thickness were compared between the AP and control groups. The ultrasound findings of the three AP groups were compared with CT findings and several clinical parameters. The ultrasound characteristics of the normal pancreas were also determined to investigate AP risk factors associated with pancreatic thickness.

Results and Discussion: Among the included factors of echogenicity, sex, and age, multiple regression analysis identified echogenicity and sex as significant AP risk factors (p＜0.001). Echogenicity was significantly lower in the AP group than the control group. Comparison of the pancreatic thickness based on echogenicity between the AP and control groups revealed that the high-level echogenicity of types 0 and 1 was more frequent in the AP group (p＜0.001); a similar trend between the AP groups was observed for type 2 echogenicity as well. There were significant differences in pancreatic echogenicity (p＝0.026), peripancreatic and perinephric fluid (p＜0.001), peripancreatic fat stranding (p＝0.005), and AP localized to the pancreatic tail (p＝0.007) among the three AP groups.

Conclusion: In normal cases, pancreatic thickness was characterized based on a thick appearance with high intensity by ultrasound. In AP, the pancreas was significantly enlarged and hypoechoic. However, the assessment of the pancreas should be based on comparison with normal pancreatic echo brightness. Peripancreatic and perinephric fluid are the most important findings that must be detected for definitive AP diagnosis. Our findings suggest that the diagnosis of AP localized in the pancreatic tail was difficult because of the anatomical approach.