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NOT FOR PUBLICATION, QUOTATION, OR CITATION RESOLUTION NO. 29 BE IT RESOLVED, that the American College of Radiology adopt the ACR–SPR Practice Parameter for the Performance of Renal Scintigraphy Sponsored By: ACR Council Steering Committee The American College of Radiology, with more than 30,000 members, is the principal organization of radiologists, radiation oncologists, and clinical medical physicists in the United States. The College is a nonprofit professional society whose primary purposes are to advance the science of radiology, improve radiologic services to the patient, study the socioeconomic aspects of the practice of radiology, and encourage continuing education for radiologists, radiation oncologists, medical physicists, and persons practicing in allied professional fields. The American College of Radiology will periodically define new practice parameters and technical standards for radiologic practice to help advance the science of radiology and to improve the quality of service to patients throughout the United States. Existing practice parameters and technical standards will be reviewed for revision or renewal, as appropriate, on their fifth anniversary or sooner, if indicated. Each practice parameter and technical standard, representing a policy statement by the College, has undergone a thorough consensus process in which it has been subjected to extensive review and approval. The practice parameters and technical standards recognize that the safe and effective use of diagnostic and therapeutic radiology requires specific training, skills, and techniques, as described in each document. Reproduction or modification of the published practice parameter and technical standard by those entities not providing these services is not authorized. Revised 2013 (Resolution 51)* ACR–SPR PRACTICE PARAMETER FOR THE PERFORMANCE OF RENAL SCINTIGRAPHY PREAMBLE This document is an educational tool designed to assist practitioners in providing appropriate radiologic care for patients. Practice Parameters and Technical Standards are not inflexible rules or requirements of practice and are not intended, nor should they be used, to establish a legal standard of care1. For these reasons and those set forth below, the American College of Radiology and our collaborating medical specialty societies caution against the use of these documents in litigation in which the clinical decisions of a practitioner are called into question. The ultimate judgment regarding the propriety of any specific procedure or course of action must be made by the physician or medical physicist in light of all the circumstances presented. Thus, an approach that differs from the practice parameters, standing alone, does not necessarily imply that the approach was below the standard of care. To the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set forth in the practice parameters when, in the reasonable judgment of the practitioner, such course of action is indicated by the condition of the patient, limitations of available resources, or advances in knowledge or technology subsequent to publication of the practice parameters. However, a practitioner who employs an approach substantially different from these practice parameters is advised to document in the patient record information sufficient to explain the approach taken. 1 Iowa Medical Society and Iowa Society of Anesthesiologists v. Iowa Board of Nursing, ___ N.W.2d ___ (Iowa 2013) Iowa Supreme Court refuses to find that the ACR Technical Standard for Management of the Use of Radiation in Fluoroscopic Procedures (Revised 2008) sets a national standard for who may perform fluoroscopic procedures in light of the standard’s stated purpose that ACR standards are educational tools and not intended to establish a legal standard of care. See also, Stanley v. McCarver, 63 P.3d 1076 (Ariz. App. 2003) where in a concurring opinion the Court stated that “published standards or guidelines of specialty medical organizations are useful in determining the duty owed or the standard of care applicable in a given situation” even though ACR standards themselves do not establish the standard of care. PRACTICE PARAMETER Renal Scintigraphy 2017 Resolution No. 29 NOT FOR PUBLICATION, QUOTATION, OR CITATION The practice of medicine involves not only the science, but also the art of dealing with the prevention, diagnosis, alleviation, and treatment of disease. The variety and complexity of human conditions make it impossible to always reach the most appropriate diagnosis or to predict with certainty a particular response to treatment. Therefore, it should be recognized that adherence to these practice parameters will not assure an accurate diagnosis or a successful outcome. All that should be expected is that the practitioner will follow a reasonable course of action based on current knowledge, available resources, and the needs of the patient to deliver effective and safe medical care. The sole purpose of these practice parameters is to assist practitioners in achieving this objective. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 I. INTRODUCTION This practice parameter was revised collaboratively by the American College of Radiology (ACR) and the Society for Pediatric Radiology (SPR) to guide physicians performing renal scintigraphy in adult and pediatric patients. Renal scintigraphy involves the intravenous injection of a radiopharmaceutical, which is extracted from the blood by the kidneys and imaged using a gamma camera. Estimation of renal function using a well counter may be performed in conjunction with, or in lieu of, renal scintigraphy. Properly performed, renal scintigraphy is a sensitive means method for detecting, evaluating, and quantifying a variety of anatomic and physiologic abnormalities of the kidneys and urinary system. renal disorders Pharmacologic manipulation may enhance the sensitivity and specificity in certain renal diseases. It also is possible to accurately quantify some guidelines parameters of renal function. Although certain patterns are suggestive of individual disease entities, correlation of abnormal findings with clinical information, radiographs, computed tomography, magnetic resonance imaging, and other radiopharmaceutical imaging and non-imaging examinations is frequently helpful for optimal diagnosis. As with all scintigraphic examinations, correlation of findings with the results of other imaging and nonimaging procedures, as well as with clinical information, is imperative for maximum diagnostic yield The goal of renal scintigraphy is to enable the interpreting physician to detect anatomic and/or functional abnormalities of the kidneys and/or urinary tract by interpreting producing images of diagnostic quality and/or using reliable quantitative data. Application of this parameter should be in accordance with the ACR–SPR Technical Standard for Diagnostic Procedures Using Radiopharmaceuticals [1]. II. INDICATIONS Clinical indications for renal scintigraphy include, but are not limited to detection, evaluation, and/or quantification of: General indications for renal scintigraphy include, but are not limited to, evaluation and/or quantification of: 1. Renal perfusion and function, including differential (also known as split or relative) renal function 2. Glomerular filtration rate (GFR) 3. Effective renal plasma flow (ERPF) Specific indications for renal scintigraphy include, but are not limited to, detection, evaluation, and/or quantification of: 1. Urinary tract obstruction 2. Renovascular hypertension 3. Renal allograft perfusion and function and complications 4. Pyelonephritis and renal cortical scarring 5. Congenital and acquired renal abnormalities, including mass lesions 1. Renal function Renal Scintigraphy 2017 Resolution No. 29 PRACTICE PARAMETER NOT FOR PUBLICATION, QUOTATION, OR CITATION 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 2. 3. 4. 5. 6. 7. Congenital and acquired renal abnormalities, including mass lesions. Urinary tract obstruction Renovascular hypertension Pyelonephritis and parenchymal scarring. Renal allografts Guidelines of renal function, including effective renal plasma flow (ERPF), glomerular filtration rate (GFR), and differential (also known as split or relative) renal function. For information on radiation risks to the fetus, see The ACR–SPR Practice Parameter for Imaging Pregnant or Potentially Pregnant Adolescents and Women with Ionizing Radiation provides useful information on radiation risks to the fetus regardless of source. Information on managing pregnant or potentially pregnant patients undergoing nuclear medicine procedures is available from the International Commission on Radiological Protection [2-4]. III. QUALIFICATIONS AND RESPONSIBILITIES OF PERSONNEL See the ACR–SPR Technical Standard for Diagnostic Procedures Using Radiopharmaceuticals [1]. IV. SPECIFICATIONS OF THE EXAMINATION The written or electronic request for renal scintigraphy should provide sufficient information to demonstrate the medical necessity of the examination and allow for its proper performance and interpretation. Documentation that satisfies medical necessity includes 1) signs and symptoms and/or 2) relevant history (including known diagnoses). Additional information regarding the specific reason for the examination or a provisional diagnosis would be helpful and may at times be needed to allow for the proper performance and interpretation of the examination. The request for the examination must be originated by a physician or other appropriately licensed health care provider. The accompanying clinical information should be provided by a physician or other appropriately licensed health care provider familiar with the patient’s clinical problem or question and consistent with the state scope of practice requirements. (ACR Resolution 35, adopted in 2006) 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 A. Radiopharmaceuticals Radiopharmaceuticals for evaluation of the kidneys may be classified into 3 broad categories. 1. Tubular radiopharmaceuticals: mainly cleared by tubular secretion [5] 1. Technetium-99m mercaptoacetyl triglycine (MAG3) [5] a. Kinetics: Rapid extraction by tubular cells with secretion into the renal collecting system. Renal uptake is reduced by poor renal perfusion and function but is not affected as severely as with technetium-99m DTPA. b. Indications: i. Assess renal perfusion and differential function ii. Assess urinary tract obstruction iii. Assess renovascular hypertension iv. Assess renal allograft assessment v. Estimate effective renal plasma flow (ERPF) PRACTICE PARAMETER Renal Scintigraphy 2017 Resolution No. 29 NOT FOR PUBLICATION, QUOTATION, OR CITATION 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 c. Administered Activity: i. Adults: Up to 370 MBq (10 mCi) ii. Children with angiographic phase: 5.55 MBq/kg (0.15 mCi/kg); Minimum 37 MBq (1 mCi) and Maximum 148 MBq (4 mCi) [6]2 iii. Children without angiographic phase: 3.7 MBq/kg (0.10 mCi/kg); Minimum 37 MBq (1 mCi) and Maximum 148 MBq (4 mCi) [6]2 a. Glomerular radiopharmaceuticals: mainly cleared by glomerular filtration 2. Technetium-99m diethylene triamine penta-acetic acid (DTPA) a. Kinetics: Excreted predominantly by glomerular filtration and can be used to measure GFR Predominant excretion by glomerular filtration. It can be used to estimate GFR. Renal excretion of DTPA is significantly affected by reduced renal perfusion and function. b. Indications: i. Assess renal blood flow and function ii. Assess urinary tract obstruction iii. Assess renovascular hypertension iv. Assess renal allograft assessment c. Administered Activity: i. Adults: Up to 555 MBq (15 mCi) ii. Children: 3.7 to 7.4 MBq/kg (0.1-0.2 mCi/kg). Minimum 37 MBq (1 mCi). Maximum 185 MBq (5 mCi) [6]2 iii. GFR without imaging: 7.4 to 18.5 MBq (0.20 to 0.50 mCi) 3. Cortical radiopharmaceuticals: primarily incorporated by tubular cells 3. Technetium-99m dimercaptosuccinic acid (DMSA) a. Kinetics: This radiopharmaceutical is predominantly incorporated predominantly by Predominant incorporation into renal tubular cells with a minor component of glomerular filtration. It is an excellent renal parenchymal imaging radiopharmaceutical primarily that can be used for detecting and defining characterizing pyelonephritis and renal cortical scars. Indications: i. Detect and define pyelonephritis or renal cortical scars ii. Assess renal shape, size, and position iii. Assess relative functional cortical mass (eg, differential/split/relative function) Administered Activity: i. Adults: Up to 185 MBq (5 mCi) ii. Children: 1.85 MBq/kg (0.05 mCi/kg). Minimum 18.5 MBq (0.5 mCi). Maximum 100 MBq (2.7 mCi) [6]2 a. Technetium-99m mercaptoacetyl triglycine (MAG3) This radiopharmaceutical is rapidly extracted and secreted by tubular cells in a manner that is qualitatively similar to the action of orthoiodohippurate (OIH). Renal uptake of MAG3 is reduced by poor function but is not as severely as with technetium-99m diethylene triamine penta-acetic acid 2 Alternative pediatric radiopharmaceutical dosing is proposed as the EANM Dosage Card [5], which may also be found at http://www.eanm.org/publications/dosage_calculator.php?nav1d-285. Renal Scintigraphy 2017 Resolution No. 29 PRACTICE PARAMETER NOT FOR PUBLICATION, QUOTATION, OR CITATION 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 (DTPA). MAG3 may be used quantitatively or qualitatively for evaluating obstructive uropathy, renovascular hypertension, and renal allografts and has been used to estimate ERPF. Administered activity of up to 10 millicuries (370 MBq) is used for adults. administered activity for children should be determined based on body weight and should be as low as reasonably achievable for diagnostic image quality.1 [7]. Pediatric administered activity ranges from 0.05 to 0.1 millicuries (1.85 to 3.7 MBq) per kilogram, with a minimum of 0.5 millicuries (18.5 MBq) and a maximum of 5.0 millicuries (185 MBq)Error! Bookmark not defined.. 2. Glomerular radiopharmaceuticals: mainly cleared by glomerular filtration a. Technetium-99m diethylene triamine penta-acetic acid (DTPA) This radiopharmaceutical is excreted predominantly by glomerular filtration and can be used to measure GFR. excretion by the kidneys is significantly affected by reduced renal function. The radiopharmaceutical may be used to assess renal blood flow and function, renal allografts, renovascular hypertension, and obstructive uropathy. For dynamic renal scintigraphy, administered activity of up to 15 millicuries (555 MBq) may be given to adults. If the examination is performed for calculation of GFR without imaging, the administered activity may be reduced to 0.20 to 0.50 millicurie (7.4 to 18.5 MBq). Administered activity for children should be determined based on body weight and should be as low as reasonably achievable for diagnostic image quality. For children, administered activities are typically in the range of 0.1 to 0.2 millicurie (3.7 to 7.4 MBq) per kilogram, with a minimum of 1.0 millicurie (37 MBq) and a maximum of 5.0 millicuries [7] (185 MBq). b. Iodine-125 iothalamate This radiopharmaceutical is used in administered activities of 0.01 to 0.05 millicurie (0.37 to 1.85 MBq) for the nonimaging assessment of GFR. 3. Cortical radiopharmaceuticals: primarily incorporated by tubular cells a. Technetium-99m dimercaptosuccinic acid (DMSA) This radiopharmaceutical is predominantly incorporated by renal tubular cells with a minor component of glomerular filtration. It is an excellent parenchymal imaging radiopharmaceutical, primarily used for detecting and defining pyelonephritis and renal cortical scars. Technetium-99m DMSA is also is used to assess the size, shape, position, and relative functional cortical mass of the kidneys. Administered activity of up to 5.0 millicuries (185 MBq) may be given to adults. Administered activity for children should be determined based on body weight and should be as low as reasonably achievable for diagnostic image quality. For children, an administered activity of 0.05 to 0.1 millicurie (1.85 to 3.7 MBq) per kilogram is usually given, with a minimum of 0.3 millicurie (11.1 MBq) and a maximum of 3.0 millicurie (111 MBq) [7]. B. Radionuclide Renography Radionuclide renography refers to serial imaging after intravenous administration of technetrium-99m MAG3 or technetium-99m DTPA. or technetium-99m MAG3. It is used for qualitative and quantitative evaluation of differential renal function A commonly used technique involves dynamic acquisition of 1 to 2 second images for 1 minute (angiographic or vascular phase), followed by 15 to 60 second images for 20 to 30 minutes (functional uptake, cortical transit, and excretion phases). If evaluation of renal perfusion is not needed, the examination is performed without the first angiographic/vascular phase. Qualitative evaluation of regional renal perfusion, differential function, and cortical transit of radiopharmaceutical can be performed by visual analysis. Quantitative evaluation of cortical function and collecting system drainage is made using regions-of-interest that typically are applied to each whole kidney. A background region-of-interest is placed overlying soft tissue adjacent to each kidney. Differential renal function is calculated based on the relative counts accumulated in each kidney during the second minute after injection of the radiopharmaceutical. Occasionally, it may be helpful to approximate regions-of-interest to the renal cortex and the renal collecting system, although absolute segmentation of cortex and renal collecting system is difficult. If there is suspected ureteral obstruction or megaureter, regions-of-interest may be applied to the ureters. Depending on the regions-ofinterest drawn, the time-activity curves will reflect the functional uptake/accumulation and clearance of radiopharmaceutical in the whole kidney, renal cortex, renal collecting system, or ureter. The regions of interest PRACTICE PARAMETER Renal Scintigraphy 2017 Resolution No. 29 NOT FOR PUBLICATION, QUOTATION, OR CITATION 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 are typically drawn around the whole kidneys, but occasionally are limited to the renal cortex if a considerable amount of collecting system activity is present. A background region of interest is placed adjacent to each kidney. Depending on the regions of interest drawn, the time-activity curves will reflect the functional clearance of the whole kidney, renal cortex, or collecting system. The differential renal function is calculated based on the relative counts accumulated in each kidney during the second minute after injection of the radiopharmaceutical C. Diuresis Renography Diuresis renography is used to can evaluate the severity of urinary tract obstruction and can differentiate an obstructed collecting system from a dilated but nonobstructed collecting system. from a dilated system with urodynamically significant obstruction It is also is used for postoperative assessment of the useful for assessing functional and urodynamic results of corrective surgery. Diuresis renography is performed by intravenous administration of a loop diuretic (usually furosemide, although other diuretics have been used) in conjunction with radionuclide renography. The usual dose of furosemide is 0.5 to 1.0 mg/kg (1 mg/kg in children), with a maximum dosage of 40 mg. Patients on chronic diuretic therapy likely will be unresponsive to a small dose of furosemide and typically are administered their usual dose of furosemide for diuretic renography. It can be helpful to coordinate timing of renography with the medication schedule to avoid starting the renal scintigraphic examination during a pre-existing diuresis. It is important to ensure that the patient is well hydrated prior to performing diuresis renography. Intravenous fluid infusion is particularly useful in children and can be performed during the initial 20 minute renogram. A full or distended bladder can prolong renal collecting system drainage, and depending on clinical circumstances, an indwelling bladder catheter may be useful for adequate assessment of upper tract obstruction [8]. Different approaches to diuresis renography are characterized by the time of furosemide administration in relation to the time of radiopharmaceutical administration. The most commonly used approach (referred to as F +20) is intravenous administration of furosemide at or soon after the completion of 20minute (or 30 minute) radionuclide renography; dynamic 15 second to 60 second renal images are obtained for another 20 to 30 minutes. Other approaches include administering furosemide 15 minutes prior to radiopharmaceutical administration (F-15) or at the time of radiopharmaceutical administration (F-0). Region-of-interest analysis of the images obtained during the diuretic phase are used for quantitative analysis of collecting system drainage. A commonly used technique includes intravenous administration of technetium-99m MAG3 or technetium-99m DTPA and acquisition of dynamic 15-60 second posterior renal images for 20 to 30 minutes [8,9]. Furosemide, 0.5 mg/kg (1 mg/kg for children) with a maximum dose of 40 mg, is then administered intravenously, and dynamic 15-60 second renal images are obtained for another 20 to 30 minutes (F+20). Other techniques include administering furosemide 15 minutes prior to (F-15) or at the time of (F0) radiopharmaceutical administration. The initial set of images is used for evaluating differential renal function. The images obtained after administration of furosemide are used for quantitative analysis of postdiuresis clearance of the radiopharmaceutical from the dilated collecting system(s). Regions of interest, including the entire dilated collecting system(s), are drawn and a background subtracted timeactivity curve is generated Diuresis renography is usually is performed with the patient in the supine position. This may cause result in delayed clearance of the tracer radiopharmaceutical from some a dilated but nonobstructed collecting systems. Therefore, an additional posterior static image after the patient has been in an upright position for 10 to 15 minutes will may help to assess gravity-assisted clearance [8]. It is important to ensure that the patient is well-hydrated. Intravenous fluid infusion is particularly useful in children. A distended bladder may prolong renal collecting system drainage depending on clinical circumstances, an indwelling bladder catheter may be [8] necessary to assess adequately for obstruction of the upper tracts. In children, particularly in neonates, the natural history of prenatal hydronephrosis and possible urinary tract obstruction can be variable. Multiple diuretic renograms over time may be needed to detect gradual improvement Renal Scintigraphy 2017 Resolution No. 29 PRACTICE PARAMETER NOT FOR PUBLICATION, QUOTATION, OR CITATION 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 or worsening of urinary tract drainage. In neonates, renal function continues to mature after birth, and renal immaturity during the first few months after birth may delay uptake and clearance of tubular radiopharmaceuticals. Ideally, renography will be delayed until at least 3 months of age to allow for renal maturation. If this is not possible, then the diuretic renogram must be interpreted in the context of renal immaturity. The natural history of hydronephrosis in children, particularly in neonates, is variable, and definitive diagnosis of obstructive uropathy on a single diuresis renogram is often difficult. Multiple examinations at appropriate intervals may be needed to detect gradual improvement or worsening of the postdiuresis drainage. Therefore, whatever technique is used, it should be standardized in order to allow meaningful comparison of the serial examinations in each patient D. Captopril (ACE Inhibitor) Renography Renovascular hypertension is caused by hemodynamically significant stenosis of the main renal artery or one of its branches. Most hypertension is essential (idiopathic), with less than 5% having a demonstrated renovascular etiology. The prevalence of renovascular hypertension is somewhat higher in patients with risk factors that include severe hypertension and end-stage renal disease [10]. However, renal artery stenosis may be present but not be the etiology of the patient’s hypertension. Thus, the goal of ACE-1 renography is to identify the subgroup of patients in whom hypertension is due to renal artery stenosis and who could potentially respond to an intervention, such as revascularization [11]. However; renal artery stenosis may be present but not be the etiology of the patient’s hypertension. Therefore, the goal of renal scintigraphy in the evaluation of hypertensive patients is to identify those who have renal artery stenosis with associated renin-dependent hypertension and would benefit from revascularization [11] Imaging assessment for renovascular hypertension, including scintigraphy, is most appropriate in patients in whom there is a high index of suspicion. Patients with a low index of suspicion usually have essential hypertension that can be well controlled medically, and in these patients imaging is not generally indicated. In the presence of hemodynamically significant renal artery stenosis, renal perfusion pressure is reduced, resulting in activation of activating the renin-angiotensin system. Angiotensin II causes selective constriction of the efferent arterioles and raises the pressure gradient across the glomerular capillary membrane. Because of this autoregulatory mechanism, the GFR is maintained and conventional renal scintigraphy may be normal. In these patients, blockade of the conversion of angiotensin I to angiotensin II by administering angiotensin converting enzyme (ACE) inhibitors causes dilatation of the efferent arterioles. This leads to a significant but reversible decrease in GFR that is detectable on renal scintigraphy. The choice of radiopharmaceutical, ACE inhibitor, and technique of examination varies among institutions. Technetium-99m MAG3 is preferred, but technetium-99m DTPA may be used. Renal scintigraphy is performed approximately 1 hour after oral administration of 25 to 50 milligrams of captopril or 10 to 20 minutes after intravenous injection of 40 micrograms/kg (maximum 2.5 mg) of Enalaprilat. The usual administered dose dosage of captopril in children is 1 mg/kg, with a maximum of 50 mg. Food ingestion within 4 hours prior to captopril administration may decrease absorption and test accuracy [12]. Blood pressure should be measured before administration of the ACE inhibitor and monitored every 10 to 15 minutes. An intravenous line should be kept in place to allow prompt fluid replacement if the patient becomes hypotensive. Furosemide (0.25 mg/kg, maximum 20 mg) given intravenously at the time of radiopharmaceutical administration decreases radiopharmaceutical retention in the collecting systems and may facilitate detection of cortical retention of the radiopharmaceutical. The patient should be well hydrated, especially if furosemide is will be used [12]. PRACTICE PARAMETER Renal Scintigraphy 2017 Resolution No. 29 NOT FOR PUBLICATION, QUOTATION, OR CITATION 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 Chronic use of ACE inhibitors may decrease the sensitivity of ACE inhibitor renography. the test Ideally, ACE inhibitors should be are discontinued for 3 to 7 days before the test, depending on their the half-life of the specific ACE inhibitor. If stopping the patient’s ACE inhibitor is not possible, the study may examination still may be performed [11,12]. One protocol is to obtain perform a baseline scan without an prior ACE inhibitor administration, followed (on the same or following day) by a repeat examination second scan performed after administration of an ACE inhibitor [11]. on the same or following day The combined examinations help Comparison of the 2 scans helps to detect subtle ACE inhibitor induced scintigraphic abnormalities produced by ACE inhibition. An alternative protocol is to obtain perform the first scan after administration of examination with an an ACE inhibitor first [12]. A normal examination indicates a low probability for renovascular hypertension and obviates the need for a baseline examination without an ACE inhibitor. If the examination with an ACE inhibitor is abnormal, a baseline examination is performed on a following day. obtained the next day or later With the use of intravenous Enalaprilat and technetium-99m MAG3 (but not technetium-99m DTPA), both the baseline and post-ACE inhibitor scans can be completed within 60 to 90 minutes. After administration of 1 to 3 mCi of technetium-99m MAG3, a baseline scan is performed for 20 to 30 minutes. Subsequently, 40 mg/kg (maximum 2.5 mg) of Enalaprilat is administered intravenously. Ten to twenty minutes later, 8 to 10 mCi of technetium-99m MAG3 is administered, and the second scan is performed for 20 to 30 minutes [13]. E. Evaluation of Renal Allografts Renal scintigraphy has been deemed “usually appropriate” in the assessment of renal allograft dysfunction and as a postoperative screening examination for surgical complications. Technetium-99m MAG3 or technetium-99m DTPA may be used. for evaluating renal allografts Renal perfusion images are obtained using a technique similar to that outlined in section IV.B, except that an anterior projection is used and is centered over the lower abdomen and pelvis. It is possible to assess the presence or absence of renal perfusion, urine leaks, cortical infarcts, lymphoceles, hematomas, acute tubular necrosis, collecting system obstruction, urine leaks, nephrotoxic effect of medications (eg, cyclosporin A), and rejection. Comparison of serial examinations will enhance detection of subtle physiological changes [14,15]. F. Renal Cortical Imaging The radiopharmaceutical for renal cortical imaging is technetium-99m DMSA. In most cases, optimal parenchymal imaging can be obtained 2 to 4 hours after radiopharmaceutical administration. injection If there is significant hydronephrosis, delayed images imaging at 24 hours or administration of furosemide prior to delayed imaging may be helpful. If there is no retention of tracer radiopharmaceutical in the collecting system, relative renal function can be calculated. When assessing differential renal function in children with vesicoureteral reflux, refluxed radiopharmaceutical may interfere with accurate quantification [16]. In adults, between 500,000 and 1,000,000 counts per image are desirable. At least 300,000 counts or 5 minutes per image should be used when imaging children [17]. A 256 × 256 matrix is preferred. Pinhole (4 mm aperture) images may be useful, especially in infants. Pinhole images should be acquired for a minimum of 100,000 to 150,000 counts or 10 minutes per image. At a minimum, posterior and both posterior oblique views should be obtained. When imaging a “horseshoe” or pelvic kidney, anterior images should also be obtained. Single-photonemission computed tomography (SPECT) imaging may also be performed, although no definitive improvement in sensitivity has been demonstrated, and false-positive SPECT defects may decrease specificity [18] Determination of differential renal function should be performed on the posterior planar image using a parallel-hole collimator. Background and depth corrections are optional. Depth correction, which can be accomplished by using the geometric mean, should be considered when there is a major variation or abnormality in the shape or location of the kidneys such as with a “horseshoe or pelvic kidney. Single photon emission computed tomography Renal Scintigraphy 2017 Resolution No. 29 PRACTICE PARAMETER NOT FOR PUBLICATION, QUOTATION, OR CITATION 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 (SPECT) imaging also may be performed, although no definitive improvement in sensitivity has been demonstrated, and false-positive SPECT defects may decrease specificity [18]. 377 378 Reporting should be in accordance with the ACR Practice Parameter for Communication of Diagnostic Imaging Findings [23]. 379 380 381 382 383 384 385 G. Estimation of GFR The radiopharmaceutical used for estimating GFR are is technetium-99m DTPA. and iodine-125 iothalamate Numerous protocols are available, some of which involve imaging [5,17,19-21]. Whichever protocol is used, it is imperative that the technique is meticulous and that the protocol is followed assiduously. H. Estimation of ERPF Technetium-99m MAG3 does not provide a true ERPF measurement, but it provides a value that can be extrapolated to an ERPF equivalent measurement. Numerous protocols are available, some of which involve imaging [5,19,22]. Whichever protocol is used, it is imperative that the technique is meticulous and that the protocol is followed assiduously. V. EQUIPMENT A gamma camera with a parallel-hole collimator is required. When magnification is desired, a pinhole collimator may be used. For adults, a large-field-of-view gamma camera (400 mm) is desirable, but for children a smallfield-of-view camera (250 to 300 mm) is also acceptable. If a large-field-of-view camera is used in a pediatric patient, “zoom” or pinhole collimation may be used. For most situations using technetium-99m-labeled tracers radiopharmaceuticals, low-energy all-purpose/general all-purpose (LEAP/GAP) collimators are sufficient. If renal cortical anatomic detail is desired, a high-resolution collimator will improve image quality, provided the count density is adequate. For digital acquisition, a 128 × 128 matrix is the minimum necessary, but a 256 × 256 matrix may be preferred. SPECT (or SPECT/CT in adults) renal imaging using technetium-99m DMSA may be helpful in some circumstances. VI. DOCUMENTATION The report should include the radiopharmaceutical, used and the dose administered activity, and route of administration, as well as any other pharmaceuticals administered, also with dose dosage and route of administration. VII. RADIATION SAFETY Radiologists, medical physicists, registered radiologist assistants, radiologic technologists, and all supervising physicians have a responsibility for safety in the workplace by keeping radiation exposure to staff, and to society as a whole, “as low as reasonably achievable” (ALARA) and to assure that radiation doses to individual patients are appropriate, taking into account the possible risk from radiation exposure and the diagnostic image quality necessary to achieve the clinical objective. All personnel that work with ionizing radiation must understand the key principles of occupational and public radiation protection (justification, optimization of protection and application of dose limits) and the principles of proper management of radiation dose to patients (justification, optimization and the use of dose reference levels) http://www-pub.iaea.org/MTCD/Publications/PDF/Pub1578_web-57265295.pdf PRACTICE PARAMETER Renal Scintigraphy 2017 Resolution No. 29 NOT FOR PUBLICATION, QUOTATION, OR CITATION Facilities and their responsible staff should consult with the radiation safety officer to ensure that there are policies and procedures for the safe handling and administration of radiopharmaceuticals and that they are adhered to in accordance with ALARA. These policies and procedures must comply with all applicable radiation safety regulations and conditions of licensure imposed by the Nuclear Regulatory Commission (NRC) and by state and/or other regulatory agencies. Quantities of radiopharmaceuticals should be tailored to the individual patient by prescription or protocol Nationally developed guidelines, such as the ACR’s Appropriateness Criteria®, should be used to help choose the most appropriate imaging procedures to prevent unwarranted radiation exposure. Additional information regarding patient radiation safety in imaging is available at the Image Gently® for children (www.imagegently.org) and Image Wisely® for adults (www.imagewisely.org) websites. These advocacy and awareness campaigns provide free educational materials for all stakeholders involved in imaging (patients, technologists, referring providers, medical physicists, and radiologists). Radiation exposures or other dose indices should be measured and patient radiation dose estimated for representative examinations and types of patients by a Qualified Medical Physicist in accordance with the applicable ACR technical standards. Regular auditing of patient dose indices should be performed by comparing the facility’s dose information with national benchmarks, such as the ACR Dose Index Registry, the NCRP Report No. 172, Reference Levels and Achievable Doses in Medical and Dental Imaging: Recommendations for the United States or the Conference of Radiation Control Program Director’s National Evaluation of X-ray Trends. (ACR Resolution 17 adopted in 2006 – revised in 2009, 2013, Resolution 52). 386 387 388 389 390 391 392 393 394 395 396 Nuclear medicine and molecular imaging examinations should administer the lowest activity to obtain images of diagnostic quality. National initiatives have partnered to provide such dosage optimization for adults and dosage optimizing calculators for pediatric patients. The following is a web link for this information and several references: www.imagegently.org. For further information, see the ACR–AAPM Practice Parameter for Reference Levels and Achievable Administered Activity for Nuclear Medicine and Molecular Imaging [6,24,25]. VIII. QUALITY CONTROL AND IMPROVEMENT, SAFETY, INFECTION CONTROL, AND PATIENT EDUCATION Policies and procedures related to quality, patient education, infection control, and safety should be developed and implemented in accordance with the ACR Policy on Quality Control and Improvement, Safety, Infection Control, and Patient Education appearing under the heading Position Statement on QC & Improvement, Safety, Infection Control, and Patient Education on the ACR website (http://www.acr.org/guidelines). 397 398 Equipment performance monitoring should be in accordance with the ACR–AAPM Technical Standard for Medical Nuclear Physics Performance Monitoring of Gamma Cameras [26]. ACKNOWLEDGEMENTS 399 400 401 402 403 404 This practice parameter was revised according to the process described under the heading The Process for Developing ACR Practice Parameters and Technical Standards on the ACR website (http://www.acr.org/guidelines) by the Committee on Practice Parameters and Technical Standards – Nuclear Medicine and Molecular Imaging of the ACR Commission on Nuclear Medicine and Molecular Imaging and the Committee on Practice Parameters – Pediatric Radiology of the ACR Commission on Pediatric Radiology, in collaboration with and the SPR. 405 Renal Scintigraphy 2017 Resolution No. 29 PRACTICE PARAMETER NOT FOR PUBLICATION, QUOTATION, OR CITATION Collaborative Committee – members represent their societies in the initial and final revision of this practice parameter ACR Chun K. Kim, MD, Chair Murray D. Becker, MD, PhD, FACR Frederick Grant, MD Rathan M. Subramaniam, MD, PhD, MPH SPR Deepa R. Biyyam, MBBS Neha Kwatra, MD S. Ted Treves, MD 406 Committee on Practice Parameters and Technical Standard – Nuclear Medicine and Molecular Imaging (ACR Committee responsible for sponsoring the draft through the process) Kevin P. Banks, MD, Co-Chair Richard K.J. Brown, MD, FACR, Co-Chair Twyla B. Bartel, DO Murray D. Becker, MD, PhD, FACR Erica J. Cohen, DO, MPH Joanna R. Fair, MD Perry S. Gerard, MD, FACR Erin C. Grady, MD Edward D. Green, MD Jennifer J. Kwak, MD Chun K. Kim, MD Charito Love, MD Joseph R. Osborne, MD, PhD Rathan M. Subramaniam, MD, PhD, MPH Stephanie P. Yen, MD 407 Committee on Practice Parameters – Pediatric Radiology (ACR Committee responsible for sponsoring the draft through the process) Beverley Newman, MB, BCh, BSc, FACR, Chair Lorna P. Browne, MB, BCh Timothy J. Carmody, MD, FACR Brian D. Coley, MD, FACR Lee K. Collins, MD Monica S. Epelman, MD Lynn Ansley Fordham, MD, FACR Kerri A. Highmore, MD 408 409 410 411 412 413 414 415 Sue C. Kaste, DO Tal Laor, MD Terry L. Levin, MD Marguerite T. Parisi, MD, MS Sumit Pruthi, MBBS Nancy K. Rollins, MD Pallavi Sagar, MD M. Elizabeth Oates, MD, Chair, Commission on Nuclear Medicine and Molecular Imaging Rathan M. Subramaniam, MD, PhD, MPH, Vice Chair, Commission on Nuclear Medicine and Molecular Imaging Marta Hernanz-Schulman, MD, FACR, Chair, Commission on Pediatric Radiology Jacqueline A. Bello, MD, FACR, Chair, Commission on Quality and Safety Matthew S. Pollack, MD, FACR, Chair, Committee on Practice Parameters and Technical Standards Comments Reconciliation Committee Darlene F. Metter, MD, FACR, Chair Richard Strax, MD, FACR, Co-Chair Kimberly E. Applegate, MD, MS, FACR Kevin P. Banks, MD Murray D. Becker, MD, PhD, FACR Jacqueline A. Bello, MD, FACR Deepa R. Biyyam, MBBS Richard K.J. Brown, MD, FACR Kate A. Feinstein, MD, FACR Frederick Grant, MD Marta Hernanz-Schulman, MD, FACR William T. Herrington, MD, FACR Chun K. Kim, MD Neha Kwatra, MD Paul A. Larson, MD, FACR Beverley Newman, MD, BCh, BSc, FACR M. Elizabeth Oates, MD Matthew S. Pollack, MD, FACR Rathan M. Subramaniam, MD, PhD, MPH Timothy L. Swan, MD, FACR, FSIR S. Ted Treves, MD 416 PRACTICE PARAMETER Renal Scintigraphy 2017 Resolution No. 29 NOT FOR PUBLICATION, QUOTATION, OR CITATION 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 REFERENCES 1. American College of Radiology. ACR-SPR technical standard for diagnostic procedures using radiopharmaceuticals. Available at: http://www.acr.org/~/media/5E5C2C7CFD7C45959FC2BDD6E10AC315.pdf. Accessed December 23, 2015. 2. American College of Radiology. ACR-SPR practice parameter for imaging pregnant or potentially pregnant adolescents and women with ionizing radiation. Available at: http://www.acr.org/~/media/9E2ED55531FC4B4FA53EF3B6D3B25DF8.pdf. Accessed December 23, 2015. 3. Demeter S, Applegate KE, Perez M. Internet-based ICRP resource for healthcare providers on the risks and benefits of medical imaging that uses ionising radiation. Ann ICRP 2016; 45:148-155. 4. International Commission on Radiological Protection. Pregnancy and medical radiation. ICRP Publication 84, Annals of the ICRP 2000; 30:1. 5. Blaufox MD. Procedures of choice in renal nuclear medicine. J Nucl Med 1991; 32:1301-1309. 6. American College of Radiology. ACR-AAPM practice parameter for reference levels and achievable administered activity for nuclear medicine and molecular imaging. Available at: http://www.acr.org/~/media/3B6B6F39D0214495BCA6D5D2E9900A56.pdf. Accessed April 20, 2016. 7. Lassmann M, Treves ST. Pediatric Radiopharmaceutical Administration: harmonization of the 2007 EANM Paediatric Dosage Card (Version 1.5.2008) and the 2010 North American Consensus guideline. Eur J Nucl Med Mol Imaging 2014; 41:1636. 8. Conway JJ, Maizels M. The "well tempered" diuretic renogram: a standard method to examine the asymptomatic neonate with hydronephrosis or hydroureteronephrosis. A report from combined meetings of The Society for Fetal Urology and members of The Pediatric Nuclear Medicine Council--The Society of Nuclear Medicine. J Nucl Med 1992; 33:2047-2051. 9. O'Reilly P, Aurell M, Britton K, Kletter K, Rosenthal L, Testa T. Consensus on diuresis renography for investigating the dilated upper urinary tract. Radionuclides in Nephrourology Group. Consensus Committee on Diuresis Renography. J Nucl Med 1996; 37:1872-1876. 10. Lewin A, Blaufox MD, Castle H, Entwisle G, Langford H. Apparent prevalence of curable hypertension in the Hypertension Detection and Follow-up Program. Arch Intern Med 1985; 145:424427. 11. Taylor AT, Jr., Fletcher JW, Nally JV, Jr., et al. Procedure guideline for diagnosis of renovascular hypertension. Society of Nuclear Medicine. J Nucl Med 1998; 39:1297-1302. 12. Taylor A, Nally J, Aurell M, et al. Consensus report on ACE inhibitor renography for detecting renovascular hypertension. Radionuclides in Nephrourology Group. Consensus Group on ACEI Renography. J Nucl Med 1996; 37:1876-1882. 13. Sfakianakis GN, Georgiou M, Cavagnaro F, Strauss J, Bourgoignie J. Fast protocols for obstruction (diuretic renography) and for renovascular hypertension (ACE inhibition). J Nucl Med Technol 1992; 20:193-206. 14. Boubaker A, Prior JO, Meuwly JY, Bischof-Delaloye A. Radionuclide investigations of the urinary tract in the era of multimodality imaging. J Nucl Med 2006; 47:1819-1836. 15. Dubovsky EV, Russell CD, Bischof-Delaloye A, et al. Report of the Radionuclides in Nephrourology Committee for evaluation of transplanted kidney (review of techniques). Semin Nucl Med 1999; 29:175-188. 16. Piepsz A, Blaufox MD, Gordon I, et al. Consensus on renal cortical scintigraphy in children with urinary tract infection. Scientific Committee of Radionuclides in Nephrourology. Semin Nucl Med 1999; 29:160-174. 17. Piepsz A, Ham HR. Pediatric applications of renal nuclear medicine. Semin Nucl Med 2006; 36:16-35. 18. Brenner M, Bonta D, Eslamy H, Ziessman HA. Comparison of 99mTc-DMSA dual-head SPECT versus highresolution parallel-hole planar imaging for the detection of renal cortical defects. AJR Am J Roentgenol 2009; 193:333-337. 19. Blaufox MD, Aurell M, Bubeck B, et al. Report of the Radionuclides in Nephrourology Committee on renal clearance. J Nucl Med 1996; 37:1883-1890. 20. Gates GF. Glomerular filtration rate: estimation from fractional renal accumulation of 99mTc-DTPA (stannous). AJR Am J Roentgenol 1982; 138:565-570. Renal Scintigraphy 2017 Resolution No. 29 PRACTICE PARAMETER NOT FOR PUBLICATION, QUOTATION, OR CITATION 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 21. Gordon I, Anderson PJ, Orton M, Evans K. Estimation of technetium-99m-MAG3 renal clearance in children: two gamma camera techniques compared with multiple plasma samples. J Nucl Med 1991; 32:1704-1708. 22. Russell CD, Taylor A, Eshima D. Estimation of technetium-99m-MAG3 plasma clearance in adults from one or two blood samples. J Nucl Med 1989; 30:1955-1959. 23. American College of Radiology. ACR practice parameter for communication of diagnostic imaging findings. Available at: http://www.acr.org/~/media/C5D1443C9EA4424AA12477D1AD1D927D.pdf. Accessed December 23, 2015. 24. Fahey FH, Bom HH, Chiti A, et al. Standardization of Administered Activities in Pediatric Nuclear Medicine: A Report of the First Nuclear Medicine Global Initiative Project, Part 2-Current Standards and the Path Toward Global Standardization. J Nucl Med 2016; 57:1148-1157. 25. Fahey FH, Ziniel SI, Manion D, Baker A, Treves ST. Administered Activities in Pediatric Nuclear Medicine and the Impact of the 2010 North American Consensus Guidelines on General Hospitals in the United States. J Nucl Med 2016; 57:1478-1485. 26. American College of Radiology. ACR-AAPM technical standard for medical nuclear physics perfomance monitoring of gamma cameras. Available at: http://www.acr.org/~/media/35D4D3277B9B4D1BB11737D425927F96.pdf. Accessed December 23, 2015. *Practice guidelines and technical standards are published annually with an effective date of October 1 in the year in which amended, revised, or approved by the ACR Council. For practice guidelines and technical standards published before 1999, the effective date was January 1 following the year in which the practice or technical standard was amended, revised, or approved by the ACR Council. Development Chronology for this Practice Parameter 1995 (Resolution 30) Revised 1998 (Resolution 19) Revised 2003 (Resolution 16) Amended 2006 (Resolution 35) Revised 2008 (Resolution 12) Revised 2013 (Resolution 51) Amended 2014 (Resolution 39) PRACTICE PARAMETER Renal Scintigraphy 2017 Resolution No. 29