Quantitative assessment with SPECT imaging of stress injuries of the pars interarticularis and response to bracing.

The evaluation and management of acute spondylolysis remains unclear in part because of outcome data that are primarily subjective. The aim of this study was to evaluate and monitor these patients objectively using quantitative single-photon emission computed tomography (SPECT). Thirty-four patients were so observed clinically between 1987 and 1996 and were studied with an initial and at least one follow-up SPECT scintigram. Initial radiographs and planar bone scans failed to demonstrate the pars lesion in 53 and 19% of the patients, respectively. The average SPECT ratio before brace treatment was 1.45. After treatment, this ratio significantly decreased to 1.27 (p = 0.03). A subset of patients remained symptomatic at follow-up. Their reduction in SPECT ratio averaged only 2.8% as compared with 13% for the remainder of the patients (p = 0.01). Patients diagnosed and braced in the early, more active stage of the condition (with greater intensity on SPECT) had more predictable symptom relief. An initial SPECT ratio of >1.5 was associated with complete symptom resolution after brace treatment. Patients treated with activity restriction only (>3 months) before bracing were more likely to have persistent symptoms and more modest improvement on SPECT (p = 0.01). These data, which use SPECT scintigraphy, support prompt treatment with brace immobilization for acute spondylolysis in children and adolescents.

Technetium-99m-MAG3 in early identification of pyelonephritis in children.

UNLABELLED: The purpose of this study was to determine whether 99mTc-mercaptotriacetylglycine (MAG3) can substitute for 99mTc-glucoheptonate (GH) in the detection of pyelonephritis. METHODS: One hundred thirty renal scintigraphies were evaluated retrospectively in 38 children (21% boys, 79% girls; age range 1 mo-21 yr; mean age 7.2 yr) referred for evaluation during an acute clinical urinary tract infection and for follow-up studies. Twelve topographical regions were designated on each kidney. Each area was graded for severity of decreased radionuclide localization: mild (Grade 1), moderate (Grade 2) or marked (Grade 3). Early posterior views of MAG3 studies were compared to delayed posterior GH images. In all patients, both studies were performed on the same day. RESULTS: Eighty-two studies were performed during an acute clinical infection and 48 were performed as follow-up. Seventy-seven percent of the studies had focal cortical lesions. Of all the cortical lesions identified by GH, MAG3 detected 74% (match lesions). A comparable percentage of lesions was identified in each region by both studies. GH scintigraphy detected 261 lesions (63 Grade 1, 149 Grade 2 and 49 Grade 3), and MAG3 detected 201 lesions (37 Grade 1, 117 Grade 2 and 47 Grade 3). MAG3 was unable to recognize 60 lesions identified by GH studies in 11 patients (mismatch lesions). Of these, 41% (26 of 63) were Grade 1, 21% (32 of 149) were Grade 2 and 4% (2 of 49) were Grade 3. In three cases, MAG3 identified lesions not seen by GH (reverse mismatch); all had acute symptomatic infection. CONCLUSION: These data document that MAG3 in the early phase of the study (1-2 min) can detect Grade 2 to Grade 3 cortical lesions in patients with pyelonephritis, but it is less effective in detecting Grade 1 lesions.

Surgery versus observation for managing obstructive grade 3 to 4 unilateral hydronephrosis: a report from the Society for Fetal Urology.

PURPOSE: The Society for Fetal Urology has undertaken the first multicenter prospective randomized study of high grade obstructive unilateral hydronephrosis to evaluate the natural history of untreated obstruction and compare it to the benefits of pyeloplasty. MATERIALS AND METHODS: Since 1991, infants with isolated unilateral Society for Fetal Urology grade 3 hydronephrosis and ipsilateral obstruction with greater than 40% differential renal function on well tempered renography were studied. Patients were randomly assigned to observation or pyeloplasty groups. Renal ultrasound and well tempered renography were performed biannually for 1 year and yearly thereafter. Crossover criteria for surgery included concurrent worsening of isotope washout and increasing grade of hydronephrosis or a greater than 10% point loss in percent differential renal function that was noted between studies. The end point of the study was the 3-year anniversary of randomization. RESULTS: A total of 32 infants from 10 centers were randomized equally to 2 groups. The starting grade of hydronephrosis and percent differential renal function were similar between the 2 groups. At 6 months and 1 year the grade of hydronephrosis was significantly reduced (p < 0.02) and well tempered renography was significantly more likely to demonstrate no obstruction (p < 0.03) in the surgical group compared with the observation group. The mean percent differential renal function remained stable and similar in both groups. Reduced hydronephrosis and resolution of obstruction in the surgery group persisted as a trend at the 2 and 3-year anniversaries. In the observation group 4 patients (25%) showed enough renal deterioration to qualify for crossover to surgery. CONCLUSIONS: Infant pyeloplasty significantly improved the grade of hydronephrosis and drainage pattern at 6 months and 1 year postoperatively, when compared with observation. Renal function stabilization was similar for either management approach. However, 25% of the patients satisfied objective criteria of status deterioration requiring pyeloplasty.

The prognostic value and significance of serial bone scintigraphy in Legg-Calvé-Perthes disease.

We reviewed 44 consecutive patients treated for Legg-Calvé-Perthes disease who underwent serial technetium 99m diphosphonate bone scintigraphy. The average follow-up was 4.4 years. The bone-scintigraphy classification characterizes the A pathway by early lateral column formation not seen in the B pathway. Pathway A had 20 hips. The average age at presentation was 6.1 years. At last follow-up, this group had an average Mose classification of 1.2 and Catterall score of 2.4, without any patient having "head-at-risk" signs or requiring operative treatment. Pathway B had 20 hips. The average age at presentation was 5.8 years. At last follow-up, this group had an average Mose classification of 5.2, a Catterall score of 3.5, and 18 patients had head-at-risk signs, with 11 requiring operative treatment. Our bone-scintigraphy classification preceded the radiographic head-at-risk signs by an average of 3 months, allowing earlier treatment and correlated with subsequent femoral head involvement.

Detection of bone lesions in Langerhans cell histiocytosis: complementary roles of scintigraphy and conventional radiography.

PURPOSE: This research was undertaken to determine the relative sensitivity of scintigraphic and radiographic bone survey examinations in detecting bone lesions in various regions of the skeleton in patients with a histopathologic diagnosis of Langerhans cell histiocytosis (LCH). PATIENTS AND METHODS: Radionuclide skeletal scintigraphy (RNSS) and x-ray skeletal surveys (XRSS) of 42 children with a histopathologic diagnosis of LCH were evaluated retrospectively. RESULTS: Of the 191 lesions detected in 42 patients, 36 (19%) were missed on RNSS and 55 (29%) were missed on XRSS. Most of the missed lesions on RNSS were in the skull (26 of 36). XRSS also missed 13 skull lesions seen on RNSS. Most of the lesions missed on XRSS were in the ribs (20 of 30 rib lesions), whereas RNSS identified 29 of them. XRSS also missed 13 of 38 lesions in the spine and pelvis, while RNSS demonstrated all of them. Both modalities showed comparable sensitivity in the extremities. CONCLUSION: RNSS has a greater value in detecting sites of bone involvement with LCH than reported previously. RNSS is more sensitive than XRSS in detecting histiocytic lesions in the ribs, spine and pelvis and less sensitive in identifying lesions in the skull.

Bone mineral disorders in children: evaluation with dual x-ray absorptiometry.

PURPOSE: To evaluate the utility of dual x-ray absorptiometry (DXA) in children with bone mineral disorders. MATERIALS AND METHODS: In phase 1, radial DXA was compared with single-energy photon absorptiometry (SPA) (n = 117). In phase 2, radial and lumbar bone mineral density (BMD) measured with DXA and second metacarpal cortical thickness were compared (254 examinations, 224 children). RESULTS: For radial BMD, DXA and SPA correlated well (r = .956) and SPA-equivalent values could be calculated from DXA measurements (mean residual error = 0.024 g/cm2). After controlling for age, sex, weight, and height, partial correlations were very small for lumbar BMD with radial BMD (r = .186) and lumbar BMD with cortical thickness (r = .158), and slightly better for radial BMD with cortical thickness (r = .544). Z scores also correlated poorly with no meaningful correlation for lumbar BMD with radial BMD (r = .07) CONCLUSION: In children with bone mineral disorders, radial DXA and SPA measurements correlate well. However, lumbar BMD, radial BMD, and cortical thickness correlate poorly and lumbar BMD frequently does not identify abnormality in patients with abnormal radial BMD. Lumbar BMD alone is not adequate for evaluation of bone mineral status in these patients.

Outcome of nonspecific hydronephrosis in the infant: a report from the Registry of the Society for Fetal Urology.

Since 1988 the Society for Fetal Urology has worked to evaluate if there is consensus on management of infants with nonspecific hydronephrosis. Initially, multicenter agreement on the criteria to grade hydronephrosis and method of diuretic renography were developed to promote similarities in how infant kidneys with nonspecific hydronephrosis were profiled for grade (0 to 4), per cent differential function by diuretic renography and drainage response by diuretic renography (obstructed, not obstructed or indeterminate). Between 1989 and 1992 a total of 33 pediatric urologists from 21 cities registered 464 cases (582 kidneys) of hydronephrosis. Of the cases 275 (59%) were managed by observation and 189 (41%) were treated surgically. The operated kidneys showed profiles (hydronephrosis grade 3 or greater and diuretic renography obstructed) that were significantly different from the profiles of observed kidneys (hydronephrosis grade 2 or less and diuretic renography no obstruction) (p < 0.001 each). Six months postoperatively the mean grade of hydronephrosis (1.8) and diuretic renography diagnosis (no obstruction) were significantly better than they were preoperatively (p < 0.001 each). In addition, postoperatively the mean grade of hydronephrosis, diuretic renography diagnosis and per cent differential function were similar to age matched observed kidneys. We conclude that when radiographic tests are done similarly, there is consensus in the management of infant hydronephrosis by surgery or observation.

Hepatobiliary scintigraphy in children with cystic fibrosis and liver disease.

UNLABELLED: Intra- and extrahepatic impairment of biliary drainage is important in the pathogenesis of liver disease in cystic fibrosis. Distal common bile duct obstruction is reported to occur in 13% to 96% of these patients. Between 1975 and 1993, 17 of 372 children (4.5%) with cystic fibrosis attending The Children's Memorial Medical Center in Chicago had liver disease based on clinical and laboratory findings. METHODS: Hepatobiliary scintigraphy (HBS) with 99mTc-DISIDA was performed on 12 of the 17 children (mean age at the time of exam was 9 yr, with a range of 1 mo to 21 yr). RESULTS: All had hepatomegaly, four had splenomegaly and two had bleeding esophageal varices. Twenty HBS exams on these 12 patients documented nonvisualization of the gallbladder in 7, dilated intrahepatic ducts in 6 (only the left lobe was involved in 3 patients), nonvisualization of bowel in two, delayed peaking time in the liver (> 10 min) in four patients, and delayed clearance from the liver parenchyma (T1/2 > 20 min) in 11. There appears to be a spectrum of abnormal HBS findings in cystic fibrosis patients with liver disease. These are delayed clearance of liver parenchyma, nonvisualization of the gallbladder and dilated intrahepatic ducts with a predilection for the left lobe of the liver. These abnormal findings fluctuate in time and may not correlate with the findings on ultrasonography. CONCLUSION: Quantitative hepatobiliary scintigraphy is a valuable tool in the evaluation and management of the liver disease in this patient population.

A scintigraphic classification of Legg-Calvé-Perthes disease.

The onset of Legg-Calvé-Perthes (LCP) disease, avascular necrosis of the proximal femoral epiphysis, frequently is clinically undetectable for months before presentation. This traditional X-ray methods of diagnosis are insensitive for the diagnosis of early LCP as well as nonspecific for the diagnosis of advanced LCP. The X-ray may remain normal for weeks to months after the onset of LCP, and other disorders (steroid osteopathy, epiphyseal dysplasia) simulate the X-ray appearance of LCP during its later stages. Localization of bone-avid radiopharmaceuticals depends principally on bone perfusion and metabolism. Bone scintigraphy is a highly sensitive and specific means of detecting changes in bone perfusion. An understanding of the vascular anatomy of the pediatric hip and its revascularization mechanisms is essential for correlating the scintigraphic findings with the stages of healing in this disorder. Revascularization of bone can occur by recanalization of existing vessels or by neovascularization through the development of new vessels. Recanalization is a rapidly occurring process (minutes to weeks), whereas neovascularization is a prolonged process (months to years). The recanalization process has a characteristic scintigraphic pattern beginning with the visualization of a "lateral column" and is associated with a good prognosis for eventual outcome in LCP. Neovascularization also has a characteristic scintigraphic appearance ("base filling" and "mushrooming"), which is associated with a poorer prognosis because of the prolonged interval required for healing, which places the femoral head at risk for complications such as fracture, collapse, and extrusion. The scintigraphic staging classification presented here, when correlated with a modified Waldenstrom X-ray staging, readily differentiates three mechanisms of revascularization. The A (allright) track scintigraphic pattern represents the recanalization process, a process of short duration and good prognosis. The B (bad) track scintigraphic pattern represents the process of neovascularization, a process of long duration and poorer prognosis. A third process also is described in which complications of the healing process (collapse, extrusion), particularly during the reabsorptive phases of bone reconstitution when the bone is weakened, can cause conversion from track A to track B. Bone scintigraphy is useful in LCP for its ability to detect the disorder in its initial stages, thus allowing earlier treatment, and to provide prognostic information that may affect therapy.

Spine pain in children.

Spine pain in children as an isolated symptom is infrequently seen in clinical practice. However, as opposed to spine pain in adults, it is accompanied by a relatively higher frequency of pathology. Diagnostic imaging is a necessary follow up to the physical examination and laboratory studies. Standard radiography is usually the initial imaging study. Frequently, however, additional imaging with bone scintigraphy, computed tomography, or magnetic resonance imaging is necessary to add sensitivity and specificity to the clinical presentation. We describe the disease entities, pathophysiology, and imaging characteristics of the varied pathologies responsible for spine pain in children.

The role of bone scintigraphy in detecting child abuse.

This review of diagnostic imaging in cases of suspected child abuse characterizes the significant differences between bone scintigraphy and x-ray evaluation, describes the advantages and disadvantages of each modality, postulates on the specific mechanisms of injury that produce the characteristic scintigraphic findings, and emphasizes the influences that scintigraphic studies have on the medical, social, and legal aspects of child abuse. The major advantages of bone scintigraphy are its increased sensitivity (25% to 50%) in detecting evidence of soft tissue as well as bone trauma in child abuse. Furthermore, it is postulated that the specific mechanisms of inflicting the trauma relate to the patient's size and are characterized by bone scintigraphy. During fits of anger or frustration, the perpetrator of child abuse grasps the small infant or child by the thorax during the shaking activity. This produces characteristic rib injuries. The older and heavier child is more likely to be grabbed by the extremities, which produces periosteal injuries manifested as characteristic abnormal localizations in the diaphyses of the extremities. The roentgenograms of these injuries are frequently normal. The importance of bone scintigraphy is its complementary nature in defining and characterizing the extent and severity of trauma from child abuse. Such findings have direct bearing on the medical, social, and legal outcomes for the abused child. The quality of scintigraphic imaging is important, requiring the use of magnification techniques in the infant. The interpretation of the scintigraphic images depends on an understanding of the mechanisms by which the radionuclide localizes in bone. The same traumatic incident can lead to decreased, normal, or increased localization at the trauma site. Radionuclide scintigraphy is a complementary rather than competitive imaging modality to X-ray evaluation in the diagnosis and management of physical child abuse.

Does early pyeloplasty really avert loss of renal function? A retrospective review.

We reviewed 75 cases of isolated, unilateral pediatric ureteropelvic junction obstruction and 167 diuretic radionuclide renograms performed during the last 8 years. Differential function of the affected kidney was calculated using scintillation count data at 1 and 3 minutes, and the area under the renogram curve between 1 and 3 minutes. There was no significant difference among the 3 measures of per cent differential function for a given patient. Per cent differential function on the first renogram preoperatively neither declined as age at presentation advanced nor did it vary according to the clinical presentation. Similarly, the changes in postoperative per cent differential function were unaffected by the age at initial presentation, manner of presentation, occurrence of postoperative complications or the surgeon. These data do not support the concept that pyeloplasty for the isolated, unilateral ureteropelvic junction obstruction should be performed early to avert loss of renal function.

Ultrasound grading of hydronephrosis: introduction to the system used by the Society for Fetal Urology.

The Society for Fetal Urology (SFU) was founded in 1988 to study the postnatal evolution of prenatally detected anomalies of the urinary tract by following those neonates whose prenatal studies have brought them to medical attention while asymptomatic. The SFU has attempted to standardize methods of performing and grading the ultrasound and radionuclide examinations in this population. A system to grade upper tract dilatation or hydronephrosis (HN) imaged by ultrasound has been developed and is being used by SFU members in 36 institutions. The appearance of the calices, renal pelvis and renal parenchyma are key in determining the grade of HN and are illustrated in this article.

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.

Perinatal hydronephrosis (HN) and hydroureteronephrosis (HUN) are recognized more frequently as the routine use of prenatal ultrasonography increases. The decision-making process for those instances of urinary tract dilatation that require surgical correction and those that do not is based in part on the findings of diuresis renography. The methodology for performing this test has differed among nuclear medicine practitioners and the surgical findings are occasionally discrepant from the diuretic renogram interpretation. Consequently, the Society of Fetal Urology (SFU) and the Pediatric Nuclear Medicine Council (PNMC) of the Society of Nuclear Medicine met to develop by consensus a more uniform methodology. A standard method has been agreed upon for the following facets of diuretic renography: patient preparation (hydration and bladder catheterization), diuresis renography technique (radiopharmaceutical used, patient position during examination, data acquisition parameters, diuretic pharmaceutical and dosage, time of injection and regions of interest to monitor diuretic effect), and data analysis (percent differential renal function, curve pattern analysis and methods of measuring diuretic response). Pooled diuresis renogram data are being collected for analysis for correlation with surgical results and clinical outcomes to determine the most appropriate information to be derived from the diuretic renogram in neonates with HN and HUN.

Grading nephroureteral dilatation detected in the first year of life: correlation with obstruction.

To understand better the significance of pediatric idiopathic nephroureteral dilatation the renal ultrasound images of patients less than 1 year old with hydronephrosis or hydroureteronephrosis were graded and compared to the radiological diagnosis of obstruction as determined by diuresis renography and/or urography. The study included 73 boys and 30 girls with hydronephrosis (76 patients) or hydroureteronephrosis (27). For hydronephrosis obstruction was diagnosed in 56 children (74%) and involved 61 of 97 kidneys (63%). For obstructed kidneys the mean grade of hydronephrosis (3.4 +/- 0.7 standard deviation) was statistically different from that of nonobstructed kidneys (1.6 +/- 0.8 standard deviation) (p less than 0.05). When the value to predict obstruction was set at grade 3 hydronephrosis or greater there was an 88% sensitivity and 95% specificity. For hydroureteronephrosis obstruction was diagnosed in 15 of 27 children (56%) and involved 17 of 34 kidneys (50%). The degree of dilatation was weighted as a score to assess the grades of hydronephrosis and ureteral dilatation, namely hydroureteronephrosis score equals grade of hydronephrosis plus grade of ureteral dilatation. In obstructed megaureters the mean hydroureteronephrosis score (5.8 +/- 1.0) was statistically different from that for nonobstructed megaureters (mean hydroureteronephrosis score 2.7 +/- 1.9) (p less than 0.001). When the value to predict obstruction was set at hydroureteronephrosis score of 5 or greater there was a 94% sensitivity and 80% specificity. Although ultrasound examination alone cannot be used to diagnose urinary obstruction, the radiological diagnosis of obstruction is linked with the grade of hydronephrosis or score of hydroureteronephrosis.

"Well-tempered" diuresis renography: its historical development, physiological and technical pitfalls, and standardized technique protocol.

Differentiating the various causes of hydronephrosis from that of obstruction can be very difficult. Diuretic renography has been adopted as a noninvasive clinical management tool to assist in this differentiation. However, the correlation of the results of diuresis renography, the Whitaker test, and the surgical results has only been between 40% and 85%. This is believed to be due to the many physiological factors and technical pitfalls of the technique. These include variable renal function, variable compliance of the collecting system, the effect of back pressure from a full bladder, the state of hydration, the choice of radiopharmaceutical, and the timing of the diuretic injection. Even the technique of measuring the clearance half-time (T 1/2) is controversial, with at least eight different methods defined. In order to diminish the effect of these variables, a standardized protocol for diuretic renography has been proposed by a consortium of members of the Society for Fetal Urology and the Pediatric Nuclear Medicine Club of the Society of Nuclear Medicine. These include a standardized hydration with a dilute glucose solution, bladder catheterization and measurement of urine output response, uniform radiopharmaceutical choice, and diuretic dose with specific timing of the diuretic injection. The various methods for T 1/2 calculation are illustrated, and various stereotypical renogram and diuresis response curves are offered as aids in the interpretation of the study. Diuresis renography is one of the most complex functional studies in nuclear medicine today. A thorough understanding of the physiological basis for diuresis renography and the pitfalls of the technique is required for its appropriate use in the management of patients suspected of urinary tract obstruction.