Deep learning-based classification of rectal fecal retention and analysis of fecal properties using ultrasound images in older adult patients.

AIM: The present study aimed to analyze the use of machine learning in ultrasound (US)-based fecal retention assessment. METHODS: The accuracy of deep learning techniques and conventional US methods for the evaluation of fecal properties was compared. The presence or absence of rectal feces was analyzed in 42 patients. Eleven patients without rectal fecal retention on US images were excluded from the analysis; thus, fecal properties were analyzed in 31 patients. Deep learning was used to classify the transverse US images into three types: absence of feces, hyperechoic area, and strong hyperechoic area in the rectum. RESULTS: Of the 42 patients, 31 tested positive for the presence of rectal feces, zero were false positive, zero were false negative, and 11 were negative, indicating a sensitivity of 100% and a specificity of 100% for the detection of rectal feces in the rectum. Of the 31 positive patients, 14 had hard stools and 17 had other types. Hard stool was detected by US findings in 100% of the patients (14/14), whereas deep learning-based classification detected hard stool in 85.7% of the patients (12/14). Other stool types were detected by US findings in 88.2% of the patients (15/17), while deep learning-based classification also detected other stool types in 88.2% of the patients (15/17). CONCLUSIONS: The results showed that US findings and deep learning-based classification can detect rectal fecal retention in older adult patients and distinguish between the types of fecal retention.

Establishing a Methodology for Ultrasound Evaluation of Pharyngeal Residue in the Pyriform Sinus and Epiglottic Vallecula.

BACKGROUND: Assessing the presence of pharyngeal residue in the pyriform sinus and epiglottic vallecula is important because insufficient pharyngeal clearance is a risk factor for aspiration pneumonia. Improvements in the performance of ultrasound to visualize the pyriform sinus and epiglottic vallecula are needed. The aim of this study was to establish a method to visualize the pyriform sinus and epiglottic vallecula with ultrasound to detect pharyngeal residue. METHODS: We used real-time virtual sonography (ie, a fusion of magnetic resonance imaging and ultrasound imaging) as the scanning method to visualize the pyriform sinus and epiglottic vallecula without residue in 4 healthy individuals. Using established ultrasound methodology and fiberoptic endoscopic evaluation of swallowing, 35 subjects with dysphagia were studied to investigate the performance of ultrasound to detect pharyngeal residue. RESULTS: The fusion ultrasound images showed that transverse scans at the level of the laryngeal prominence and above the hyoid bone using a linear array transducer can be used to visualize the pyriform sinus and the epiglottic vallecula, respectively. We obtained 238 ultrasound images of the pyriform sinus from 35 subjects and 82 images of epiglottic vallecula from 26 of 35 subjects. The ultrasound images with fiberoptic endoscopic evaluation of swallowing showed that areas of high echogenicity in the pyriform sinus and epiglottic vallecula are related to the presence of pharyngeal residue. The presence of high-echogenicity areas resulted in a sensitivity of 92.0% and specificity of 71.9% for detecting pharyngeal residue in the pyriform sinus and a sensitivity of 86.7% and specificity of 63.6% for detecting pharyngeal residue in the epiglottic vallecula. CONCLUSIONS: Transverse ultrasound scans at the level of the laryngeal prominence and above the hyoid bone enable the visualization of the pyriform sinus, epiglottic vallecula, and pharyngeal residue.

Development and evaluation of automated ultrasonographic detection of bladder diameter for estimation of bladder urine volume.

Bladder urine volume has been estimated using an ellipsoid method based on triaxial measurements of the bladder extrapolated from two-dimensional ultrasound images. This study aimed to automate this process and to determine the accuracy of the automated estimation method for normal and small amounts of urine. A training set of 81 pairs of transverse and longitudinal ultrasound images were collected from healthy volunteers on a tablet-type ultrasound device, and an automatic detection tool was developed using them. The tool was evaluated using paired transverse/longitudinal ultrasound images from 27 other healthy volunteers. After imaging, the participants voided and their urine volume was measured. For determining accuracy, regression coefficients were calculated between estimated bladder volume and urine volume. Further, sensitivity and specificity for 50 and 100 ml bladder volume thresholds were evaluated. Data from 50 procedures were included. The regression coefficient was very similar between the automatic estimation (ß = 0.99, R2 = 0.96) and manual estimation (ß = 1.05, R2 = 0.97) methods. The sensitivity and specificity of the automatic estimation method were 88.5% and 100.0%, respectively, for 100 ml and were 94.1% and 100.0%, respectively, for 50 ml. The newly-developed automated tool accurately and reliably estimated bladder volume at two different volume thresholds of approximately 50 ml and 100 ml.

[The evaluation of stored feces in elderly patients by ultrasonography: Three case studies].

Providing defecation care can be challenging because bowel movements cannot be directly observed in home-care settings, and the objective evaluation of constipation symptoms is difficult, particularly for elderly patients with cognitive impairment. We evaluated the use of rectal ultrasonography (US) to assess the properties and volume of feces in three cases with different fecal properties. Case 1: In a 94-year-old man with normal feces (Bristol stool score: BS type 4), rectal US revealed a crescent-shaped high-echo area without acoustic shadow that was present until the next defecation. Case 2: In a 92-year-old woman with hard stool (BS type 1), rectal US showed a crescent-shaped strong-echo area with acoustic shadow that was present until the next defecation. The length of the high-echo area gradually increased during the observation period and decreased after defecation in Cases 1 and 2. Case 3: In a 67-year-old man with watery stool (BS type 7), rectal US revealed a low-peripheral-frequency-echo area without acoustic shadow. Rectal ultrasonography was able to demonstrate the presence or absence of hard stool, which was observed as a crescent-shaped a strong, high-echo area with acoustic shadow; the presence or absence of hard stool may be evaluated based on these findings. Furthermore, the fecal volume may be able to be evaluated based on the long diameter of the crescent-shaped high-echo area. Determining the best course of defecation care based on the fecal properties/volume evaluated using rectal US will likely be possible in the future.

Ultrasonographic evaluation of changes over time in one defecation cycle in adults with functional constipation: A report of two cases.

We described fecal retention during the defecation cycles of adults with functional constipation via ultrasonography (US) of the large intestine. US was performed continuously after the last defecation until the next defecation. We defined the fecal finding level on US as follows: weak fecal retention, a marginally high echo in the colonic lumen; or strong fecal retention, a strongly echoic colon lumen with showing a crescent-shaped acoustic shadow on transverse images and haustrations on longitudinal images. The findings confirmed weak fecal retention in the colon throughout the defecation cycle and a pattern of strong fecal retention in the descending and sigmoid colon and over the colon, including the transverse colon and ascending colon, in patients with functional constipation.

Assessment of rectal feces storage condition by a point-of-care pocket-size ultrasound device for healthy adult subjects: A preliminary study.

The aim of this study was to assess rectal feces storage condition by a pocket-size ultrasonography (PUS) in healthy adults so as to define normal rectal defecation desire. Participants were first assessed rectum by PUS imaging immediately after defecation desire (pre-defecation). Nurses checked the amount and quality of the participants' feces using King's Stool Chart and Bristol stool scale. Finally, PUS was performed for defecation with no defecation desire (post-defecation). Pre-defecation PUS detected high echo area in all patients. All of the post-defecation PUS did not detect high echo area (perfectly no recognizable high echo area in 54.5%, high echo line in 36.4%, and low echo of entire circumference in 9.1% of the patients). Average diameter of rectal crescent was 4.22 ± 0.8 cm. Bristol Stool Scale 1 or 2 (indicating hard stool) of pre-defecation PUS indicated high echo area and acoustic shadow in 100% of the patients. This study showed that healthy adult with defecation desire had high average rectal echo area of 4.0 cm in diameter. PUS may be able to define the rectum diameter for defecation desire of elderly people. PUS is capable of assessing fecal retention of the rectum for point-of-care examinations in home care.