The ultrasound echo signals from organs contain various physical information, and many studies have been conducted for a long time to provide new diagnostic information using these signals. In this article, an overview of the research and development that the author has conducted for the diagnosis of liver tissue characteristics are described while looking back on the history. In the case of texture analysis, the purpose of the study was initially to extract the features of liver fibrosis, but it was found that it is suitable (rather advantageous) for the quantification of fatty liver. Thus, the analysis algorithm and product specifications were also improved to meet that need. As for fatty liver, the importance of early detection of non-alcoholic steatohepatitis (NASH) has increased, so we extended the investigation to quantification of the attenuation coefficient of the liver, and after some trials of prototypes, the real-time quantitative measurement function was realized.

Fatty liver is defined as steatosis affecting > 5% of hepatocytes. Fatty liver disease, especially non-alcohol-related fatty liver, is collectively referred to as non-alcoholic fatty liver disease (NAFLD). Recently, it has been reported that liver fibrosis is an important factor in the prognosis of NAFLD. Although B-mode ultrasound has been used to diagnose fatty liver disease, good sensitivity and specificity are generally not achieved unless more than 30% of the liver is found to be fatty. Recently, quantitative evaluation of steatosis using ultrasound attenuation has become available. Based on real-world clinical data, it is now possible to diagnose steatosis affecting > 5% of hepatocytes using ultrasound attenuation. In addition, the diagnosis of liver fibrosis using ultrasound elastography has been established, and the role of ultrasound in the clinical setting of fatty liver is important.

“Orthopaedics” is a Greek word derived from “orthos” meaning “straight” and “paedios” meaning “child”. Orthopaedics means “the technique of preventing and correcting physical deformities in children”. Due to the declining birthrate and aging population in Japan, there are fewer opportunities for outpatient examinations for paediatric musculoskeletal diseases, which were the origin of orthopaedics. As a result, missed or delayed diagnosis has become a problem. It is necessary to diagnose diseases that require early intervention at an appropriate time since children are still growing and developing. In conventional orthopaedic outpatient clinics, X-rays are the main diagnostic imaging tool, and the pathology is investigated based mainly on bones. However, the joints of growing children have a lot of cartilage, and it is necessary to use our imagination when reading X-rays. In recent years, the high image quality of ultrasound imaging systems has made it possible to observe the musculoskeletal components. Ultrasonography is especially useful in children because it is free of radiation exposure and can be performed without sedation even in younger children.

The case was an 83-year-old man who was taking steroids due to adrenal insufficiency. Facial edema and leg edema worsened, and he was admitted for detailed examination. Transthoracic cardiac ultrasound examination revealed a membranous structure of about 20 mm attached to the anterior leaflet of the mitral valve, and showed edematous movement protruding into the left ventricular outflow tract during contraction. Further detailed observation with transesophageal cardiac ultrasound revealed that the membranous structure was accessory mitral valve tissue attached to the anterior leaflet of the mitral valve by a string-like structure. Although no other cardiac malformations were observed, a pressure gradient in the left ventricular outflow tract was observed.

A 30-year-old man, who underwent urethroplasty for hypospadias at three years of age, visited a hospital complaining of scrotal induration and terminal dribbling. Magnetic resonance imaging for assessing this induration revealed a 3-cm subscrotal mass. Thereafter, the patient was referred to our department for further evaluation. Scrotal ultrasonography demonstrated a well-circumscribed mass with acoustic shadowing. Based on image findings of ultrasonography, computed tomography, and urethrography, he was diagnosed with urethral stone in the neourethra. Since it was impossible to perform transurethral lithotripsy owing to severe meatal stenosis, this urethral stone was removed by meatotomy and incising a part of the patient’s neourethra. Urethral stone is recognized as one of the late complications after urethroplasty for hypospadias. Urethral stricture, diverticulum, and hair are causes of urethral stone following hypospadias repair. In this case, scrotal ultrasonography was an important and useful modality for us to strongly suspect that the subscrotal mass was a huge urethral stone.

A 30-year-old primiparous woman was referred to our perinatal center because of fetus growth restriction at 19 weeks of gestation with estimated fetal weight -1.8 SD, AFI 4.6 cm, and oligohydramnios. Fetal morphological assessment revealed normal findings, except for single umbilical artery. A karyotype of 46,XX was found at amniocentesis. During the course of pregnancy, fetal growth was estimated at between -1.8 and -2.0 SD, but the fetus was developing. The amount of amniotic fluid remained at 2 cm or more in the amniotic fluid pocket, and the Biophysical Profiling Score was 10 points. She visited our hospital because of decreased fetal movements at 37＋4 weeks of gestation. The amniotic fluid index was less than 1 cm, and severe prolonged deceleration was observed. Thus, caesarean section was performed due to diagnosis of non-reassuring fetal status. A female infant weighing 2481 g (-0.55 SD) with 5/6 (1/5 min) Apgar score was delivered. Absence of peripheral malformation and a normal placenta were observed. The infant’s breathing state deteriorated after birth, and neonatal death due to respiratory failure resulted despite immediate intensive care. Autopsy revealed left hypoplastic lung and bilateral hypoplastic kidneys. After temporal oligohydramnios around 19 weeks of gestation, long-term oligohydramnios was not observed. The cause of death was not clinically determined, but the autopsy revealed renal hypoplasia and lung hypoplasia. Further, the alveoli were small and the septum was thick and immature. Even when temporal oligohydramnios occurs during early-mid gestation, this case suggests that lung immaturity can occur.

In varicose veins in the lower extremities, the veins dilate due to venous valve dysfunction and are generally saphenous or the lateral branch type. We report three very rare cases of varicose veins originating from a tibial perforator. The first case is a woman in her 60s. She visited our hospital with a varicose vein (C1) in her left lower extremity. The second case is a man in his 50s. He visited our hospital with bilateral lower limb edema and bilateral varicose veins (C4a). The third case is a man in his 60s. He visited our hospital with left lower extremity edema and venous dilatation (C4a). Ultrasonography revealed a small hole on the anterior surface of the tibia on the affected side, which was common to all three cases, and a dilated blood vessel covering the small hole was depicted. On color flow imaging using milking and on pulse Doppler, venous blood flow from the inside of the tibia to the outside of the bone through a small hole was observed. The diagnosis was varicose veins of the lower extremities derived from a perforator of the tibia. For varicose veins derived from an incompetent tibial perforator, ultrasonography was the only examination that could identify the causative vein.