(TRUS) Transrectal sonography (also called transrectal ultrasonography, transrectal echography (TRE), endorectal ultrasound (ERUS or EUS)) is an ultrasound procedure used to examine the prostate gland, the rectum or bladder.
A small, lubricated transducer placed into the rectum releases sound waves, which create echoes as they enter the region of interest. A computer creates a picture called a sonogram.
TRUS is commonly used for guidance during a prostate needle biopsy and may be used to deliver brachytherapy and monitor cancer treatment. Transrectal ultrasonography detects enlargement, tumors and other abnormalities of the prostate, rectal polyps, rectal cancer, perianal infection, and sphincter muscle injuries. TRUS is also performed on male patients with infertility to view the prostate and surrounding structures and on patients with suspected bladder conditions or disease to view the bladder.

See also Transurethral Sonography, Endoscopic Ultrasound, Pelvic Ultrasound, Rectal Probe, Biplane Probe, Endocavitary Echography and High Intensity Focused Ultrasound.

The temporal area is the thinnest portion of the skull and the squamous component with less cancellous bone provides ultrasound permeability. The transtemporal window is found between the angle of the eye and the pinna of the ear above the zygomatic ridge. Finding this window can be difficult because size and location vary with each patient (more difficult in elderly and females) and from one side to the other.
This window allows the insonation of the middle, anterior and posterior cerebral arteries, the anterior and posterior communicating, and the terminal internal carotid.

See also Transcranial Doppler.

(TTE) Transthoracic echocardiography is a common type of cardiac ultrasound and is used to evaluate the size and function of the heart.

Indications:
TTE requires no sedation or special patient preparation. After the application of ECG electrodes and ultrasound couplant, the probe is maneuvered over the chest in the area adjacent to the breast bone and under the left breast, to provide the different views of the heart. Usually the images will be obtained lying relaxed on the left side. Other views can be sampled lying on the back with the knees bent, or sitting in an upright position.

See also Bicycle Stress Echocardiography and Transesophageal Echocardiography.

Transurethral echography or sonography is used to detect small tumors of the urinary bladder or to visualize the urethra and surrounding muscles with special transducers. The bladder neck can be visualized using a transrectal probe.
In addition, high intensity focused ultrasound provides treatment of benign prostatic hyperplasia and adenocarcinoma of the prostate. Small catheter-based sectored tubular or planar transducers with highly directional energy deposition and rotational control are used for precise treatment. Regions of the prostate can be selective coagulatet while monitoring and controlling the treatment with MRI.

See also Urologic Ultrasound, Lithotripsy, Reflux Sonography, Ultrasound Therapy, Interventional Ultrasound and Thermotherapy.

(TVS) The transvaginal sonography (transvaginal echography or endovaginal ultrasound), uses a small vaginal transducer (5-7.5 MHz) that is inserted into the vagina to depict the inner female organs (uterus, ovaries, vessels). As a general rule, ultrasound works better when the probe is close to the area being examined. Compared with a sonogram through the abdominal wall, the transvaginal technique produces a sharper image, not only because of the close proximity to the uterus, but also because the better signal to noise ratio of the used transducer.

Indications:

The advantage of transvaginal sonography is being able to get very close to the structures of the pelvis, and thus get better images and a more reliable diagnosis.

See also Pelvic Ultrasound, Hysterosalpingo Contrast Sonography.