Images of the Interior of the Body - Case Study Example

Introduction Ultrasound imaging, also known as ultrasound scanning or sonography is the viewing of images of the interior of the body by the use of high-frequency sound waves. Ultrasound scanning is useful to visualize various organs of the body as well as the vascular system. This essay briefly describes the uses of ultrasound in the imaging department and the vascular department. Uses of ultrasound in the imaging department 1. Head a. brain-in the newborn, because of the relatively thin parietal bones and patent fontanelles, one can use a conventional B-scanner or real-time sector scanner to get a cross sectional image of the body of the lateral and third ventricles. The thickness of the cerebral cortex can be measured relative to the biparietal diameter of the skull. The ratio of these measurements is the brain mantle index, a useful indicator of the degree of hydrocephalus (Repacholi and Benwell 2003.) b. eyes-with a water bath and focused transducers, the entire 2.5cm of the globe can be displayed. Axial length measurements of the eye are used to determine the power of an intraocular lens. Other uses include; detection of staphyloma, microphthalmia, foreign body localization, and retinal detachment (Repacholi and Benwell 2003.) 2. Neck a. thyroid gland-ultrasound can be used to evaluate isotopically “cold” nodules and to determine whether they are cystic or solid in consistency (Repacholi and Benwell 2003.) 3. heart- ultrasound is useful in the investigation of pericardial effusion and cardiac lesions. The echo pattern of the effusion can predict whether the effusion is serous or particulate. For echocardiographic recording, the M-mode unit is used (Repacholi and Benwell 2003.) Excellent visualization of the mitral, aortic, and tricuspid valves can be obtained. Rupture of a chordae tendinae or papillary muscle will result in a more gross regurgitation for which the M-mode is specific. Thickening of the aortic valve cusp due to fibrosis and /or calcification can be recognized in the M-mode study (Repacholi and Benwell 2003.) The mid-portion of the intraventricular septum and posterior left ventricular wall can be studied in the M-mode. The mitral valve has a specific pattern of motion in case of the obstructive form of idiopathic hypertrophic subaortic stenosis (IHSS), left atrial myxoma and aortic insufficiency (Repacholi and Benwell 2003.) The left side of the heart and to a lesser degree, the right ventricle can be adequately assessed using the M-mode only. In the left ventricle, one can accurately measure the short axis dimension, thickness of the septum and the posterior wall in both systole and diastole. With this, a reasonably accurate assessment of function can be calculated. In congenital heart disease, ultrasound is quite useful. It provides enough information to make the diagnosis, and eliminates the need for angiography (Repacholi and Benwell 2003.) 4. Breast- ultrasound is useful in the evaluation of mass lesions and even for mass screening. It can localize the mass, differentiate a cystic from a solid lesion and if cystic, aid in the aspiration (Repacholi and Benwell 2003.) 5. Abdomen- ultrasound is useful in the initial investigation of masses in the abdomen. It can demonstrate the regional anatomy, independent of organ function. The pathological process can then be relegated to a specific organ system that can, if necessary, be further studied with invasive or function-dependent techniques (isoptic techniques) (Repacholi and Benwell 2003). a. GI tract-the GI tract is the only major abdominal system that eludes major ultrasonic evaluation. With the exception of the large bowel tumors and intusussception in the adult, the relationship of identifiable masses to the gut cannot be adequately assessed (Repacholi and Benwell 2003). It can asses a right upper quadrant mass in a rapid, noninvasive manner. b. Liver-the entire lobe of the liver can be well visualized and the cause for any enlargement can be identified. Tumor masses will usually present as discrete lesions within an otherwise normal parenchyma (Repacholi and Benwell 2003.) c. Kidneys- US of kidney From: UW Medicine As far as the kidneys are concerned, the pelvicalyceal system is easier to asses than the parenchyma. Even small amounts of dilatation can be appreciated. This is thus, useful in the evaluation of the anuric adult or infant (Repacholi and Benwell 2003). Recent advances with coronal scanning enhance its ability to follow the ureter throughout its length. After kidney transplantation, any ureteric obstruction, rejection with pyramidal enlargement and associated hematoma or lymphoceles can be diagnosed. Large masses in the adrenal glands can be diagnosed (Repacholi and Benwell 2003). Other applications of ultrasonography in nephrology include: guidance for the percutaneous kidney biopsy and temporary hemodialysis access placement, and vascular ultrasound of upper extremities for permanent hemodialysis access (Gosmanova et al 2009.) d. pancreas-although the pancreas are difficult to visualize ultrasonically, filling the stomach with tepid water and placing the patient in the upright or left lateral decubitus position can help to study this organ in at lease 75-85% of cases (Repacholi and Benwell 2003.) e. Spleen-massive splenic enlargement can be identified (Repacholi and Benwell 2003.) f. Gall bladder-with the ultrasound, gallstones can be visualized in 95% of cases. Even stones as small as 2 mm can be seen if high frequency, well-focused transducers are used and if the patient is placed in the left lateral decubitus position (Repacholi and Benwell 2003). The common hepatic duct can be visualized in over 95% cases. Wall thickening can be seen in case of acute or chronic cholecystitis. The common hepatic duct can be visualized but stones are only occasionally seen in the common duct (Repacholi and Benwell 2003.) g. Lymph nodes-abdominal lymphadenopathy generally involves the para aortic chain of nodes and may present a clinical picture similar to an aortic aneurysm (Repacholi and Benwell 2003.) h. Peritoneal space-ultrasound is very sensitive in detecting adult or fetal ascites (Repacholi and Benwell 2003.) 6. Pelvis a. Uterus- US image at 5weeks From: Baby Java Other than ultrasound, no other investigative technique can give as much information. The gestational sac can be visualized as early as 4 1/2 weeks menstrual age. The fetus itself is seen from 7 weeks menstrual age onwards, and the placenta at about 9 weeks menstrual age (Repacholi and Benwell. 2003.) Initially, fetal motion and the beating heart will indicate fetal well being. Later on in gestation, a great deal of fetal anatomy can be visualized. The ventricles can be seen in the head at 14 weeks menstrual age and a diagnosis of hydrocephalus can be established or ruled out (Repacholi and Benwell. 2003). Small amounts of calcification can be seen, as well as small placental cysts. The placental position in relation to the internal cervical os is readily noted, and thus it is possible to exclude the diagnosis of placenta previa (Repacholi and Benwell. 2003). A small lenticular defect in the placenta points to an abruptio placenta. The amniotic cavity is well visualized. A diagnosis of ectopic pregnancy can be made if the uterus is empty and there is a mass in the fallopian tube (Repacholi and Benwell 2003.) b. ovaries-normal ovaries are visualized, and any cyst can be identified (Repacholi and Benwell 2003.) c. bladder-ultrasound is useful in assessing residual volume, and tumors of the bladder (Repacholi and Benwell 2003.) d. Testes-ultrasonography can be used to measure the testicular volume by B-mode. in patients with clinical varicocele, unenhanced color Doppler US examination might show an increased resistive index (RI) and pulsatility index (PI) of capsular branches of testicular arteries, which may be an indicator of impaired testicular microcirculation (Schurich et al 2009.) 8. Other uses- US can be used as an adjunct to other forms of treatment to help relieve symptoms of pain, soreness, and tenderness associated with bursitis, periarthritis, fibrositis, tenosynovitis, myositis and myofascitis, rheumatoid arthritis, osteoarthritis, sciatica, brachial neuralgia and painful neuromas of the stump after amputation (Repacholi and Benwell 2003.) Endoscopic ultrasonography (EUS)-guided fine needle aspiration (EUS-FNA) is an effective technique for tissue diagnosis in patients with abnormalities of various organs. EUS-guided fine needle injection (EUS-FNI) for anti-cancer treatment includes celiac nerve blocking and drug delivery into tumors. Tailor-made medicines can be produced by chemosensitivity tests with materials obtained using EUS-FNA (Irisawa et al 2009.) Modified forms of ultrasound include phonophoresis (use of ultrasound energy for the transdermal delivery of low molecular weight drugs) and extracorporeal shock wave therapy (ESWT)-which is the use of high-energy, focused ultrasound energy, delivered using a modified lithotripter (Speed 2003.) Ultrasound has some thermal effects on tissues like, increased extensibility of collagen fibers, increased blood flow, pro-inflammatory response, and a reduction in muscle spasm. These thermal effects ultrasound can be used to relieve pain, muscle spasm, and to increase tissue extensibility. Most soft tissue problems like lesions of the tendons, ligaments and bursa can be relieved with the use of ultrasound (Speed 2003.) Uses of ultrasound in the vascular department Vascular US From: Maple Crest 1. Head-for a reliable evaluation of intracranial blood flow patterns in real-time, Transcranial Doppler ultrasonography (TCD) is probably the only non-invasive examination. Along with the anatomical information obtained from other neuroimaging modalities, it can also add some physiological information. Some of the other applications of TCD includes: enhancing intravenous thrombolysis in acute stroke, emboli monitoring, right-to-left shunt detection and vasomotor reactivity and as a tool for evaluating stroke mechanisms, plan and monitor treatment and for prognosis (Yeo and Sharma 2010) 2. Neck- even small plaques at the bifurcation of the carotid arteries can be shown by carotid artery-high-resolution real-time scanners. Further assessment of the velocity of flow across a stenotic area is also possible by adding a pulsed Doppler (Repacholi and Benwell 2003.) 3. Abdomen a. Aorta-any aneurysmal dilation of the abdominal aorta can be detected by an US. In addition to visualizing the external dimensions of the aneurysm, the size of the lumen can also be determined, which gives information about the amount of mural thrombus (Repacholi and Benwell 2003.) 4. Extremities a. arteries and veins-Doppler venography is very useful for estimating the patency, especially in the iliofemoral veins. US can also detect the flow in the arteries, and localizing the emboli following frost bite injuries (Repacholi and Benwell 2003). With the recent advent of real-time pulsed Doppler system, one can accurately visualize areas of stenosis in the carotid artery and then determine the velocity of flow through the affected segment, thereby quantiating the degree of stenosis (Repacholi and Benwell 2003.) Advances in ultrasound Some of the advances of ultrasound, which has therapeutic applications includes: high intensity focused ultrasound (HIFU) and microbubble assisted delivery of drugs and genes (Harvey et al 2003.) Microbubble contrast agents allow the dynamic detection of both the macro and microvasculature tissue flow. The clinical roles of contrast enhanced ultrasound includes: echocardiography (endocardial border detection and myocardial perfusion), radiology (focal disease of the liver), abdominal trauma (rapid assessment of injury to the liver, spleen and kidneys), malignancies (infarcts, ischemia and regions of abnormal vascularity), ovarian carcinomas (detection of neovascularisation), neovascularisation of atheromatous plaques and in aggressive joint inflammation (Cosgrove 2006), renal diseases (complicated cysts, arterial infarction and masses in the collecting system and renal vein), rheumatology (monitoring and optimizing the effectiveness of therapy), early detection of tumor recurrence, lung disease (characterizing non-ventilated tissues and interventional procedures), vascular (arterial stenosis), and detection of sentinel lymph nodes (Weskott 2008.) Real-time sonoelastography (EUS) measures tissue displacement in terms of tissue stiffness and thus, helps in the assessment of tissue elasticity (Klauser and Peetrons 2009.) Conclusion Ultrasound is useful in the imaging department to visualize any pathology in body structures including the head, eyes, neck, heart, breast, abdominal and pelvic organs. In the vascular department, vessels in the head, neck, abdomen and extremities can be visualized for any abnormality. Numerous advances have enhanced the diagnostic capabilities of ultrasound. These include the use of intensity focused ultrasound (HIFU), real-time sonoelastography and microbubble contrast agents. References Baby Java. www.babyjava.net/images/ultrasound-sac.jpg Cosgrove D. 2006. Ultrasound contrast agents: an overview. Eur J Radiol. 60(3):324-30. Gosmanova EO, Wu S, and WC.ONeill 2009. Application of ultrasound in nephrology practice. Adv Chronic Kidney Dis. 16(5):396-404. Harvey CJ, Pilcher JM, Eckersley RJ, Blomley MJ, and D.O Cosgrove 2003. Advances in ultrasound. Clin Radiol. 57(3):157-77. Irisawa A, Hikichi T, Shibukawa G, Takagi T, Imamura H and H. Ohira 2009. Interventional endoscopic ultrasonography: applications for cancer related treatment. Dig Endosc. 57-60. Klauser AS and P. Peetrons 2009. Developments in musculoskeletal ultrasound and clinical applications. Skeletal Radiol. Maple Crest. www. maplecrestimaging.com/ultrasound/ Repacholi, MH and D.A.Benwell 2003. Essentials of medical ultrasound: a practical introduction to the principles. The Humana Press Inc. Speed CA 2003. Therapeutic ultrasound in soft tissue lesions. Rheumatology. 40: 1331-1336. Schurich M, Aigner F, Frauscher F and L. Pallwein 2009. The role of ultrasound in assessment of male fertility. Eur J Obstet Gynecol Reprod Biol. UW Medicine. www. uwmedicine.washington.edu/PatientCare/Medical Weskott, H P. 2008. Emerging roles for contrast-enhanced ultrasound. Clin Hemorheol Microcirc. 40(1):51-71. Yeo LL and VK. Sharma 2010. Role of Transcranial Doppler Ultrasonography in Cerebrovascular Disease. Recent Pat CNS Drug Discov. [Epub ahead of print] Read More