Hounsfield Unit
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The Hounsfield unit is a standardized scale used in computed tomography (CT) scans to represent radiodensity. It was created by Sir Godfrey Hounsfield in 1971 and assigns a number to each point scanned, with -1000 HU representing air, 0 HU representing water, and densities increasing positively for tissues. Common tissues and materials have the following representative HU values: lung -200 to -400 HU; fat -50 to -100 HU; white matter 20-30 HU; kidney 20-40 HU; spleen 35-55 HU; grey matter 37-45 HU; blood 45-65 HU; liver 45-65 HU; hematoma 40-90 H
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The document discusses several formulas that can be used to estimate bladder capacity based on age or weight: the Koff formula uses (Age + 2) x 30 ounces; the ABC formula uses (Age x 30) / 2; Daniel Costa's formula uses [1.6 x age (months) + 45]; and the Fairhurst formula uses [7 x weight (kg)] to estimate capacity in millilitres. These formulas provide clinicians with methods to predict bladder capacity in children and infants based on their age or weight.
Principles of Endourology
Cystoscopy and ureteroscopy are endoscopic procedures used to visualize the bladder and upper urinary tract. Cystoscopy can be performed rigidly or flexibly, with rigid cystoscopes providing better optics and larger working channels while flexible cystoscopes are more comfortable for patients. Important components of cystoscopes include the telescope lens, bridge, and sheath. Rigid and flexible ureteroscopes are used to inspect the ureters and kidneys. Proper patient preparation, use of irrigation, and careful technique help ensure safe and effective visualization and potential treatment of conditions like stones.
Urologic Ultrasonography
This document discusses the basic principles of urologic ultrasonography. It covers physical principles including how soundwaves interact with tissues to create ultrasound images. It describes resolution, mechanisms of attenuation, artifacts, and modes of ultrasonography. Specific techniques for renal, pelvic, scrotal, penile, prostate, and transrectal ultrasonography are covered. Normal ultrasound anatomy and measurements are provided. Applications and limitations of various urologic ultrasound examinations are summarized.
Primary endoscopic realignment
This document discusses urethral injuries, their causes and signs, diagnostic evaluations, and various management approaches. It focuses on primary endoscopic realignment as a management option for posterior urethral injuries in men. Primary endoscopic realignment aims to correct severe distraction injuries using cystoscopy and fluoroscopy to realign the urethra, and may result in lower stricture rates compared to traditional initial suprapubic cystostomy with delayed reconstruction. The technique involves placing a guidewire and catheter through the urethra to realign it, with the catheter staying in place for 4-8 weeks.
TURP Technique (lecture n video)
This document provides guidance on transurethral resection of the prostate (TURP) techniques. It outlines a triphasic procedure involving 1) cone excision, 2) excavation of the prostate capsule, and 3) resection of apical tissue. This approach allows for rapid initial tissue removal while minimizing risks of injury. It emphasizes achieving hemostasis between stages for good visualization. Different resection methods are described for removing lateral and median lobes, including segmental, tangential, Nesbit's, Barnes', and Alcock & Flocks techniques. Landmarks like the bladder neck and veromontanum help guide apical resection.
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- Link to NephroTube website: www.NephroTube.com
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Hounsfield Unit
- 2. Hounsfield units - scale of HU, CT numbers • The Hounsfield unit (HU) is a quantity commonly used in computed tomography (CT) scanning to express CT numbers in a standardised and convenient form. Hounsfield units, created by and named after Sir Godfrey Hounsfield found it in 1971. • Through a mathematical calculation, the computer construct a graphic image, assigning a number (called Hounsfiled unit ) to represent radiodensity at each point
- 3. Matter Density (HU) Air -500 to -1000 Lung parenchyma (inspirium) -200 to -400 Fat -50 to -100 Water 0 White matter 20 to 30HU Kidney 20 to 40HU Spleen 35 to 55HU Grey matter 37 to 45HU Blood 45 to 65HU Liver 45 to 65HU Hematoma 40 to 90HU Bone 700 to 3000 Hounsfield units - scale of HU, CT numbers
- 4. Hounsfield units - scale of HU, CT numbers
- 5. REFERENCES 1. Buzug TM. Computed Tomography: From Photon Statistics to Modern Cone-Beam CT. Springer; 2008:475. 2. Heymsfield S. Human Body Composition. Human Kinetics; 2005. 3. Prokop M. Spiral and Multislice Computed Tomography of the Body. Thieme; 2003.
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