Contrast-enhanced, real-time volumetric ultrasound imaging of tissue perfusion: preliminary results in a rabbit model of testicular torsion.

Contrast-enhanced ultrasound (US) imaging is potentially applicable to the clinical investigation of a wide variety of perfusion disorders. Quantitative analysis of perfusion is not widely performed, and is limited by the fact that data are acquired from a single tissue plane, a situation that is unlikely to accurately reflect global perfusion. Real-time perfusion information from a tissue volume in an experimental rabbit model of testicular torsion was obtained with a two-dimensional matrix phased array US transducer. Contrast-enhanced imaging was performed in 20 rabbits during intravenous infusion of the microbubble contrast agent Definity® before and after unilateral testicular torsion and contralateral orchiopexy. The degree of torsion was 0° in 4 (sham surgery), 180° in 4, 360° in 4, 540° in 4, and 720° in 4. An automated technique was developed to analyze the time history of US image intensity in experimental and control testes. Comparison of mean US intensity rate of change and of ratios between mean US intensity rate of change in experimental and control testes demonstrated good correlation with testicular perfusion and mean perfusion ratios obtained with radiolabeled microspheres, an accepted 'gold standard'. This method is of potential utility in the clinical evaluation of testicular and other organ perfusion.

Neonatal scrotal haematoma: mimicker of neonatal testicular torsion.

OBJECTIVE: To describe the clinical features of neonatal scrotal haematoma and distinguish them from those of neonatal testicular torsion. PATIENTS AND METHODS: Five neonates presenting with an acute scrotum and initial diagnosis of neonatal testicular torsion were found to have neonatal scrotal haematoma. In one case the diagnosis was surgical and in four subsequent cases the diagnosis was by colour Doppler ultrasonography, and surgery was avoided. Four of the five children had risk factors associated with neonatal scrotal haematoma, including bleeding diathesis, birth trauma and high birth weight. CONCLUSIONS: The importance of including haematoma in the differential diagnosis of the acute neonatal scrotum is emphasized, as is the value of contemporary Doppler ultrasonography in making this diagnosis.

Effect of chronic, low-pressure, sterile vesicoureteral reflux on renal growth and function in a porcine model: a radiologic and pathologic study.

PURPOSE: To study the effects of chronic, low-pressure, sterile vesicoureteral reflux (VUR) on renal growth and function in a porcine model. MATERIALS AND METHODS: Unilateral VUR was created in five pigs, with the contralateral kidney serving as a control. Preoperatively, and 1 year later, ultrasonography, technetium 99m-dimercaptosuccinic acid (DMSA) scintigraphy, contrast material-enhanced computed tomography (CT), and contrast-enhanced magnetic resonance (MR) imaging were performed. Morphologic abnormalities and relative uptake of (99m)Tc-DMSA were recorded. The postcontrast enhancement ratios for parenchymal regions of interest at CT and MR imaging were determined. Ruthenium 103-labeled microspheres were used to determine regional blood flow. After the pigs were sacrificed, the kidneys were excised, weighed, and analyzed pathologically. RESULTS: Two of five refluxing kidneys had less than 45% function at scintigraphy. One of these two kidneys was small at postmortem examination. There were no other imaging or gross pathologic abnormalities. There was no significant difference in regional blood flow between the refluxing and nonrefluxing kidneys. In all of the operated on kidneys, histologic examination showed focal chronic inflammation and fibrosis. CONCLUSION: Low-pressure sterile reflux into previously normal kidneys led to mild, focal, chronic interstitial inflammation and fibrosis after 1 year. Imaging findings were normal apart from a subtle decrease in tubular function in two refluxing kidneys.

Comparative assessment of pediatric testicular volume: orchidometer versus ultrasound.

PURPOSE: Testicular volume measurements obtained with the Prader and Rochester orchidometers were compared to those obtained using scrotal ultrasound. The ability of each orchidometer versus ultrasound in detecting volume differential between 2 testes and the accuracy of orchidometer measurement by a less experienced examiner to that of a urologist were compared. MATERIALS AND METHODS: A total of 65 males were examined by the attending urologist and urology nurse using the Prader and Rochester orchidometers, and scrotal ultrasound was subsequently performed by an attending radiologist. Statistical analysis of the results was performed to determine the correlation of orchidometer measurements between examiners, as well as with ultrasound, and sensitivity and specificity of orchidometer and ultrasound in detecting defined volume differentials between testes of 10%, 15%, 20% and 25%. RESULTS: There was a strong linear relationship between testicular volume measurements using either orchidometer and ultrasound. To detect a defined volume differential as determined by ultrasound orchidometer sensitivity was weak, whereas orchidometer specificity was better. There was a strong correlation between orchidometer measurements of the urology nurse and attending urologist. CONCLUSIONS: Although the orchidometer remains valuable in assessing size of the individual testis, it is too insensitive to volume differentials relative to ultrasound to be used routinely to determine growth impairment. For this reason observation of an adolescent with varicocele should include an annual ultrasound assessment of testicular volume.

Variability of diuresis renography interpretation due to method of post-diuretic renal pelvic clearance half-time determination.

PURPOSE: We assessed variability in the interpretation of diuresis renography that may result from using different methods of clearance half-time determination. MATERIALS AND METHODS: We reviewed 152 diuresis renography studies performed at diagnosis or during followup of 53 children enrolled in a prospective study assessing the natural history of unilateral neonatal hydronephrosis. Studies were classified as nonobstructive, indeterminate or obstructive using 4 methods of half-time determination. Intermethod correlation and agreement were evaluated. We compared the proportion of nonobstructive, indeterminate and obstructive classifications by each method, and the interpretation of individual studies based on each method. RESULTS: Among methods we noted a high degree of correlation and fair to excellent agreement (Spearman rho = 0.86 to 0.92 and kappa = 0.57 to 0.86, respectively). However, in 27.8% of intermethod comparisons the proportion of studies classified as nonobstructive, indeterminate and obstructive differed significantly (p <0.05). The classification of pelvicaliceal drainage varied by method for all but the most severely dilated systems. In individual studies classification by 1 method was discordant with classification by another in 19% of comparisons. Of the discordant interpretations 97.7% involved nonobstructive versus indeterminate or indeterminate versus obstructive classifications. CONCLUSIONS: Variability in classifying drainage patterns based on half-time requires that practitioners be circumspect when applying this parameter for managing asymptomatic hydronephrosis. It also necessitates the description of quantitative methodology in published series of this important clinical problem.

Soft-tissue vascular anomalies: utility of US for diagnosis.

PURPOSE: To determine the ultrasonographic (US) features that distinguish soft-tissue hemangioma from vascular malformation and one type of malformation from another. MATERIALS AND METHODS: Eighty-seven vascular anomalies were evaluated by means of US. Lesions were assessed for the presence of solid tissue and abnormal arteries, veins, or cysts. Vessel density, peak flow velocities, and resistive indexes were compared. RESULTS: There were 49 hemangiomas and 38 vascular malformations. A significantly greater proportion of hemangiomas (48 of 49) compared with vascular malformations (zero of 38) consisted of a solid-tissue mass (P < .001). Vessel density was comparable for hemangioma and arteriovenous malformation (AVM) but significantly greater compared with the other vascular malformations (P < .001 in each case). No differences in mean arterial peak velocity were detected between hemangiomas and malformations. Mean venous peak velocity was significantly higher for AVM than for other vascular malformations and hemangioma. Mean resistive index was greater for lymphatic malformation than for hemangioma or AVM. Abnormal veins, arteries and veins, or cysts were univariate predictors for distinguishing between venous, arteriovenous, and lymphatic malformations (P < .001 in all cases). Solid-tissue mass was the only multivariate predictor for differentiating hemangioma from vascular malformation (likelihood ratio test = 109.8, P < .001). CONCLUSION: US can be used to distinguish hemangioma from vascular malformation and detect arterial flow. These distinctions are critical for subsequent management and assessing prognosis.

Acute scrotal symptoms in boys with an indeterminate clinical presentation: comparison of color Doppler sonography and scintigraphy.

PURPOSE: To compare the performance of color Doppler ultrasonography (US) and scintigraphy in assessing testicular perfusion in boys with clinically equivocal presentations. MATERIALS AND METHODS: Forty-one boys with clinically equivocal testicular perfusion underwent color Doppler US and scintigraphy. Studies were retrospectively classified as consistent with torsion, consistent with nontorsion, or indeterminate. Sensitivity and specificity were determined with alternate positivity criteria (indeterminate studies first considered positive and then negative for torsion). RESULTS: Color Doppler US demonstrated nine of 11 cases of torsion and 23 of 30 cases of nontorsion, with one false-positive and eight indeterminate studies. Scintigraphy demonstrated 10 of 11 cases of torsion and 29 of 30 cases of nontorsion, with two indeterminate studies (both in patients with inguinal testis). When indeterminate studies were considered positive for torsion, specificity was 77% for color Doppler US versus 97% for scintigraphy (P = .05). There were no other statistically significant differences between the sensitivities and specificities. CONCLUSION: Color Doppler US and scintigraphy demonstrate no statistically significant difference in ability to demonstrate testicular torsion in boys with acute scrotal symptoms and indeterminate clinical presentations. Owing to its greater specificity, scintigraphy may help prevent unnecessary surgery when color Doppler US shows equivocal flow.

Hepatic vascular anomalies in infancy: a twenty-seven-year experience.

OBJECTIVE: Infantile hemangioma and arteriovenous malformation (AVM) of the liver have a similar presentation but a different natural history, and therefore require different treatment. This study was undertaken to clarify differential diagnosis and management of these two biologically distinct vascular disorders. STUDY DESIGN: We retrospectively analyzed the records of 43 children with hepatic vascular anomalies treated during the past 27 years. RESULTS: Ninety percent were hemangiomas (n = 39); 10% were AVM (n = 4). Infants with AVM or large solitary hemangioma had hepatomegaly, congestive heart failure, and anemia as presenting symptoms at birth. Multiple hepatic hemangiomas manifested at 1 to 16 weeks of age with the same clinical triad, plus multiple cutaneous lesions (19/23). The mortality rate after treatment of hepatic AVM was 50% (2/4). The mortality rates after treatment of liver hemangiomas were as follows: resection of solitary lesions, 20% (2/10); embolization, 43% (3/7); corticosteroids, 30% (3/10); and interferon alfa-2a, 15% (2/13). CONCLUSION: Solitary hepatic hemangioma cannot always be distinguished from hepatic AVM without radiologic studies. Multiple hepatic hemangiomas are differentiated from hepatic AVM by coexistence of multiple cutaneous hemangioma and by radiologic imaging. We recommend combined embolization and surgical resection for hepatic AVM and for solitary symptomatic hemangioma, if drug therapy fails. Pharmacologic treatment is used for symptomatic multiple liver hemangiomas. Embolization allows interim control of heart failure. A decreased mortality rate after interferon alfa-2a therapy is encouraging.

MR imaging of hepatic hemangiomas of infancy and changes seen with interferon alpha-2a treatment.

The purpose of this study was to describe the appearance on magnetic resonance (MR) imaging of hepatic hemangioma, and how the appearance changes in infants who have received interferon alpha-2a (IFN) treatment. We retrospectively studied 16 MR examinations in seven infants (mean age 3.2 months; range 5 days to 13 months) who were symptomatic with hepatic hemangiomas. Five of these seven patients had MR examinations both before and after treatment with IFN. In six of the seven patients, the hepatic hemangiomas were multicentric; they were usually discrete, well-defined nodules, best seen on T2-weighted images as high intensity lesions. One patient had a large solitary heterogeneous lesion. They all exhibited fast flow (seen as flow voids on spin-echo images and high signal intensity structures on gradient-recalled echo images) and enlarged hepatic arteries and veins. There was enlargement of the proximal abdominal aorta with distal tapering. Treatment was followed by accelerated regression of the hemangiomas in size and number and variable shrinkage of the enlarged vessels. As the tumor nodules regressed, they were replaced by normal-appearing hepatic parenchyma; neither fat nor fibrosis was detected by MR imaging.

Comparison of color Doppler sonography and radionuclide imaging in different degrees of torsion in rabbit testes.

RATIONALE AND OBJECTIVES: We compared color Doppler sonography and radionuclide imaging in an animal model of variable torsion of the testes. METHODS: The testes of 19 rabbits with unilateral 0 degree (nontorsion), 180 degrees, 360 degrees, or 540 degrees torsion and contralateral nontorsion were evaluated by sonography serially over 24 hr. Color Doppler sonography and radionuclide imaging at 24 hr were compared and correlated with pathology in a subset of testes. RESULTS: Nontorsion (n = 16 testes) and 540 degrees torsion (n = 7 testes) were always correctly diagnosed at 24 hr by color Doppler sonography and radionuclide imaging. Torsion at 180 degrees (n = 2) was indistinguishable from nontorsion. With 360 degrees torsion (n = 6 testes), four testes had reduced or absent flow with color Doppler sonography, whereas only one testis was abnormal with radionuclide imaging. CONCLUSION: Nontorsion and extreme torsion of rabbit testes are well documented by radionuclide imaging and color Doppler sonography. Torsion at 360 degrees can result in variable flow alterations that are better detected by color Doppler sonography than by radionuclide imaging.

Renal dysplasia in infants: appearance on 99mTc DMSA scintigraphy.

Infantile renal dysplasias, including multicystic dysplastic kidneys (MCDK), are reported rarely to accumulate radiopharmaceuticals on renal scintigraphy. 99mTc DMSA is a highly sensitive tracer for detecting functioning renal cortical tissue and may be more suited to studying renal dysplasia than 99mTc DTPA. We reviewed the ultrasound studies and 99mTc DMSA scintigrams of 42 infants (age range 1-12 months) with known or suspected MCDK. Overall, uptake on 99mTc DMSA scintigraphy was evident in 6/41 (15%) dysplastic kidneys. Of the 18 patients who underwent nephrectomy, histopathological examination revealed that uptake correlated closely with the presence of mature renal cortical tissue in the affected kidney. Our study shows that a small, but significant number of MCDK will show low-grade uptake on DMSA scintigraphy. This finding may be relevant given the reliance placed on renal scintigraphy in planning treatment for infants with suspected MCDK, particularly with the increasing trend for the non-operative management of this condition.

Maturational changes in arterial impedance of the normal testis in boys: Doppler sonographic study.

OBJECTIVE: The use of color Doppler sonography to diagnose scrotal disorders in children has been hampered by the small size of the vessels and the slow blood flow compared with those in adults. Spectral analysis is the best means available of confirming the vascular origin of questionable color-flow signals arising from testes of small volume. The range of normal and abnormal Doppler sonographic arterial waveforms arising from the testis in boys, as distinct from those in adults, has never been described. The purpose of our study was to establish the normal range of testicular arterial impedance, measured as resistive index (RI), in both prepubertal and pubertal/post pubertal boys. SUBJECTS AND METHODS: Bilateral scrotal color Doppler sonography was performed in 33 healthy boys aged 3 days to 17.5 years. The mean RI in the parenchymal artery was measured in 44 testes and plotted against testicular volume. Chi-square statistics were used to test differences in mean RI, testicular volume, and age between testes with volumes of 4 cm3 or less and testes with volumes greater than 4 cm3. RESULTS: In testes with volumes of 4 cm3 or less, the mean RI ranged from 0.39 to 1.00 (mean, 0.87), and in testes with volumes greater than 4 cm3, the RI ranged from 0.43 to 0.75 (mean, 0.57). In 20 of 30 testes with volumes of 4 cm3 or less, the RI of parenchymal arteries was equal to 1.00 (i.e., diastolic flow was undetectable). Mean RI, testicular volume, and age were significantly different between testes with volumes of 4 cm3 or less and testes with volumes greater than 4 cm3 (p < .001 for all variables). CONCLUSION: Mean testicular RI in our samples of pubertal and postpubertal boys is decreased compared with the mean RI in prepubertal boys. Diastolic arterial flow may not be detectable in normal testes with volumes of 4 cm3 or less. Despite the existence of a statistically significant difference in mean RI between prepubertal and pubertal/postpubertal testes, substantial variability exists within each group, particularly among the prepubertal testes. Norms of testicular flow previously established for adults are therefore not routinely applicable to prepubertal boys with testicular volumes less than 4 cm3. However, RI values in normal pubertal and postpubertal boys where testicular volumes exceed 4 cm3 are comparable to those previously described in adults.

Imaging of neonatal cholestasis.

In the neonate with cholestasis, clinical features and standard tests of liver function frequently cannot distinguish between diseases of the hepatocyte and those of the biliary tree. Therefore, a multidisciplinary approach to diagnosis is required. A priority in investigation is the identification of patients requiring surgery. A correct diagnosis regarding the need for surgery can be made in the majority of cases after synthesis of information obtained from abdominal sonography, hepatobiliary scintigraphy, and liver biopsy. Intraoperative cholangiography is performed routinely to precisely delineate the anatomy of the intrahepatic and extrahepatic bile ducts.

Prenatal findings associated with a unilateral nonfunctioning or absent kidney.

Prenatal findings in infants who were postnatally found to have a unilaterally nonfunctioning cystic, dysplastic or absent kidney were evaluated to understand better the prenatal pathophysiology of these conditions. Of the 38 cases in which prenatal and postnatal renal imaging studies were done fetal renal conditions leading to postnatal dysplasia or absence included small echogenic kidneys in 3, typical multicystic dysplasia in 30, obstructive uropathy in 4 and perinephric urinoma in 1. Abnormalities were noted on postnatal imaging in 30% of the contralateral kidneys. Vesicoureteral reflux was the most commonly identified abnormality, occurring in 23% of the cases.

Neural crest tumors: I-123 MIBG imaging in children.

PURPOSE: To determine 24- and 48-hour distribution of iodine-123 metaiodobenzylguanidine (MIBG) and to establish an optimized pediatric imaging protocol. MATERIALS AND METHODS: Seventy-seven I-123 MIBG scans obtained in 33 children undergoing evaluation for neural crest tumor were reviewed. RESULTS: Activity in the salivary glands, myocardium, liver, gut, and bladder was demonstrated on almost all scans. Activity was noted in the neck muscles, thyroid gland, and uninvolved adrenal gland in fewer studies. In 20 studies, abnormal uptake was present in the chest or abdomen at 24 and 48 hours, and lesion identification was improved at 48 hours in 12 studies. Detection of skeletal lesions on 14 scans was similar at 24 and 48 hours. Foci of tumor were first detected at I-123 MIBG imaging in nine studies, and in only two patients was tumor involvement initially missed on I-123 MIBG studies. CONCLUSION: Distribution of I-123 MIBG on images in children differs from that in earlier descriptions in adults. Images of the torso at 48 hours after injection are a useful adjunct in detection of lesions.

Simultaneous occurrence of rib infarction and pulmonary infiltrates in sickle cell disease patients with acute chest syndrome.

In order to determine if a relationship exists between rib infarction and the acute chest syndrome (ACS) in sickle cell disease patients, bone scans were reviewed in 55 episodes in 38 patients with pain of suspected osseous origin. A bone scan was positive for thoracic bone infarction if abnormally increased or decreased uptake was present in ribs, sternum or thoracic spine. Radiographs were considered to be positive for ACS if there was pulmonary infiltrate or pleural effusion in the absence of laboratory or clinical evidence of bacterial pneumonia. ACS by chest x-ray was present in 22 episodes, 21 of which showed evidence of infarction of the bony thorax on bone scan. Thoracic bone infarction occurred in the absence of chest x-ray changes in only 11 episodes. This association between bone infarction and radiographic ACS was statistically significant (p < 0.001, Fisher's exact test). A strong association exists between ACS and infarction of the bony thorax. It is possible that bone infarction leads to pain, hypoventilation and the clinical picture of ACS.

Enhanced detection of vesicoureteral reflux in infants and children with use of cyclic voiding cystourethrography.

Cyclic voiding cystourethrography (VCUG) was prospectively evaluated to determine its ability to demonstrate vesicoureteral reflux (VUR) in children whose VCUG results were initially negative. The authors also assessed the effect of change in the patient's position on the detection of VUR. Seventy-seven children younger than 3 years of age, with negative results from a VCUG study performed while they were supine, underwent a second cycle of bladder filling after they were placed prone (group 1). Sixty-five children who were also younger than 3 years of age and had negative results from an initial VCUG examination performed in the usual supine position underwent a second cycle of bladder filling, which was also performed with the patient supine (group 2). VUR occurred in three children (4%) in group 1 and in eight (12%) in group 2. Most children (68.8%) in the two groups combined had grade II reflux. Cyclic VCUG increased detection of VUR, which led to a change in clinical treatment. Prone positioning did not enhance detection of VUR to the same degree as did multiple studies performed with the patient supine.

Infantile hepatic hemangioma: Doppler US.

The duplex Doppler ultrasound (US) characteristics of 13 infantile hepatic hemangiomas were reviewed to assess the utility of these characteristics in diagnosis and follow-up. Clinical correlation was available for all children, with a histologic diagnosis established in three. A variety of tumoral flow patterns were demonstrated, including arterial and venous signals with high-frequency shifts, arteries with little systolic-diastolic flow variation, and low-frequency arterial and venous signals. Follow-up studies in 12 infants documented slower flow within the tumors; one child underwent immediate surgery without follow-up examination. The Doppler US characteristics of infantile liver hemangiomas are variable and overlap with those described in the literature for malignant tumors. Doppler US is most useful in follow-up by allowing monitoring of changes in flow within tumors after therapeutic embolization or conservative management.

Bone scintigraphy in preschool children with lower extremity pain of unknown origin.

Small children often cannot describe the location of bone pain for parents or physicians. Bone scans were performed in 56 children under five years of age with lower extremity pain and/or gait abnormalities of unknown etiology. Patients with fever, and those known to have infection, child abuse, malignancy, and/or radiographic abnormalities were excluded. Thirty patients had abnormal bone scans. Abnormalities included evidence of hip synovitis (4), femoral head avascularity (2), various proximal femoral abnormalities (3), knee synovitis (3), toddler's fracture (1), various tibial or fibular abnormalities (4), and various abnormalities of the tarsal bones (16). Tarsal bone abnormalities included four with abnormal calcaneal uptake and nine with abnormal uptake in or adjacent to the cuboid bone. Correlative imaging studies were available for 26 sites, and focal bone findings were noted at only five locations. Tarsal bone abnormalities accounted for over half of the scintigraphic abnormalities in these preschool children with gait abnormalities. Abnormal uptake in/or adjacent to the cuboid bone was common and probably represented stress injury.