Factors affecting the measurement of renal length.

The variation in kidney length between the 1-minute radiograph (centered over the kidney) and the 5-minute study (centered over the mid-abdomen) was evaluated on 100 random excretory urograms. When both kidneys were measurable, the change in kidney size was discordant in 40%. Most such changes are due to changes in geometry, differences in centering, or changes in the angle of the kidney with respiration. These alterations are of much greater magnitude than the reported swelling of the kidney due to contrast medium. Since there is practically no relation between the time of injection and changes in renal image size, it makes no difference whether the 1-minute or 5-minute radiograph is selected for measurement.     

Interobserver and intraobserver variations in sonographic renal length measurements in children

Sonographic measurement of renal length is used commonly to evaluate growth of the kidneys in children. However, no previous studies have been performed to determine the degree of interobserver and intraobserver variability in such determinations. We measured the interobserver and intraobserver error in sonographic measurements of renal length obtained independently by three experienced imagers in 21 children (41 kidneys). The mean interobserver variation between any two imagers ranged from 3.87 to 5.49 mm. The mean intraobserver variation was 0.87 to 3.61 mm. The observed variability in sonographic measurement of renal length is comparable to the expected annual increase in length of the kidneys during childhood (2.2-5.7 mm per year). Therefore, caution is suggested when using sonography to evaluate renal growth in children during a year's time.     

Measurements of tooth length in panoramic radiographs. 2: Observer performance.

Observer performance in tooth-length measurements in panoramic radiography has been examined. Sixty-four teeth, evenly distributed between maxillary first molars, second premolars and mandibular first and second premolars, were fixed in plastic moulds. Each cast was radiographed with an Orthopantomograph, twice with steel balls indicating the cusps and apices of the teeth and once without them. One observer measured the radiographic tooth length twice in both radiographs with indicators in order to estimate the true radiographic tooth length and the repositioning error, and twice in the radiographs without indicators. Seven other observers measured the tooth length on the radiographs without indicators, twice applying their own criteria and twice using defined criteria. The accuracy of the tooth-length measurements was calculated by comparing the true radiographic tooth length with the measurements of the seven observers. The intra-observer variation was defined as the difference between two measurements on the same radiograph. The accuracy and the precision of the tooth-length measurements were highly influenced by the observer performance. The mean radiographic tooth length of the seven observers was closer to the true radiographic tooth length when the observers applied the defined criteria. The inter- and intra-observer variation was higher for the measurements of the maxillary teeth (0.3-1.9 mm) compared with the mandibular teeth (0.3-0.9 mm) for most observers. The highest intra-observer variation was found for the palatal root of the maxillary first molar. The intra-observer variation of four observers decreased somewhat when the defined criteria were used; for the other three observers, however, the variation increased.(ABSTRACT TRUNCATED AT 250 WORDS)     

Interobserver variability in the measurement of internal carotid stenosis.

OBJECTIVE: To assess interobserver variability in the measurement of carotid stenoses from digital subtraction angiograms displayed in different ways (nonmagnified or magnified, white or black arteries); and to compare human readers with computer-generated densitometric measurements of vessel stenosis. METHODS: Digital subtraction angiograms of 20 proximal internal carotid artery stenoses were laser printed in the following ways: (1) Nonmagnified white artery on a black background; (2) Magnified white artery on a black background; (3) Nonmagnified black artery on a white background; (4) Magnified black artery on a white background. This resulted in 80 images of internal carotid artery stenoses. These stenoses were independently measured by 4 radiologists using the North American Symptomatic Carotid Endarterectomy Trial method. A computer-generated densitometric measurement of the black nonmagnified images was also obtained. RESULTS: The most reliable stenosis measurements were obtained from the nonmagnified black and white artery images. The interobserver variability in the measurement of internal carotid stenoses using these images was quite small. Variability increased with the use of magnification. The computer-generated stenosis measurements were consistently much higher than those of the radiologists. CONCLUSION: There was significant variability in measurements made from magnified images and between human readers and computer-generated measurements. This has great clinical significance. Readers of digital angiographic images must determine the most reliable, reproducible images generated by their equipment, as these measurements significantly affect treatment of patients with symptomatic internal carotid artery stenosis.     

Second-generation sonographic contrast agents in the evaluation of renal trauma

PURPOSE: The purpose of this study was to define the indications, diagnostic accuracy and limitations of second-generation sonographic contrast agents in the evaluation of patients with renal trauma. MATERIALS AND METHODS: Between March 2004 and April 2005, 277 patients with blunt abdominal trauma were evaluated. Twenty-eight out of 277 patients had renal lesions, the severity of which was graded according to the organ injury severity scale of the American Association for the Surgery of Trauma (AAST). All the patients enrolled in the study had minor trauma and were evaluated with baseline ultrasound (US), contrast-enhanced US after injection of a second-generation contrast agent (SonoVue) and, if positive, with multiphasic multidetector computed tomography (MDCT). RESULTS: Five out of 28 traumatic parenchymal lesions with perirenal fluid collection were identified at baseline US. All 28 renal parenchymal lesions, with or without perirenal or retroperitoneal haematoma, were identified at contrast-enhanced US. Multiphase MDCT confirmed all the cases that were positive at contrast-enhanced US and demonstrated the integrity of the urinary tract in the delayed phase. CONCLUSIONS: Our experience confirmed the diagnostic accuracy of second-generation sonographic contrast material both for diagnosis and for appropriate patient management. In particular, contrast-enhanced sonography proved to be a reliable technique for the evaluation and follow-up of low-grade renal injuries. Its main advantage is reduced radiation exposure, as fewer MDCT examinations are needed, whereas its limitation is the high cost of the technique if used in unselected patients.     

Interobserver variability in the interpretation of renal digital subtraction angiography.

OBJECTIVE: Our purpose was to analyze interobserver variability in the interpretation of renal digital subtraction angiography and to describe the main factors associated with observer discrepancies. MATERIALS AND METHODS: Forty-nine cases of unilateral atheromatous renal artery stenosis of more than 60% were quantified first by local investigators in a multicenter study and then by five other radiologists. Differences between radiologists for the minimum diameter (Dmin), the reference diameter (Dref), and the percentage of stenosis of the renal arteries were analyzed. Interpretations by the local investigators were then compared with the gold standard, defined as the mean for the five radiologists. RESULTS: The average SD for estimation of all renal artery stenoses by all radiologists was 7% for stenosis percentage, 0.5 mm for Dmin, and 0.7 mm for Dref. Main discrepancies occurred more frequently in cases of weakly opacified renal artery stenosis and poststenotic dilatation. The observations of local investigators disagreed by more than two SDs (14%) with the gold standard for 11 of 49 cases (22%). CONCLUSION: The accuracy of digital subtraction angiography in renal artery interpretations is poor because of variations in evaluating both Dmin and Dref. Precise and reproducible methods for quantification of renal artery stenosis are required.     

Mesenchymal hamartomas of the liver in childhood: sonographic and CT findings

Mesenchymal hamartomas of the liver usually present within the first 2 years of life. Abdominal enlargement and respiratory distress are the most common presenting features. Pathologically, the lesion is composed of large cysts separated by septations. Review of sonograms and CT scans in nine patients shows that a large, predominantly cystic mass with internal septae is characteristic of the tumor. Angiography shows peripheral hypervascularity with a septated avascular center. A confident preoperative diagnosis of mesenchymal hamartoma based on these features is possible.     

临床型肾结核的超声声像图特征分析

目的探讨临床型肾结核的超声声像图特征。方法回顾分析42例50个病肾肾结核住院患者的病例资料,总结肾结核的超声声像图特征。结果超声诊断符合率62%。主要超声声像图特征:(1)肾实质内单发或多发低回声或无回声结构31个肾,占62%;(2)肾盂肾盏扩张27个肾,占54%;(3)合并输尿管结核18例,21个肾,占42%;(4)肾萎缩并钙化3个肾,占6%。结论临床型肾结核超声表现呈多样性,但仍有一定特征,结合临床可作出初步诊断。     

Doppler sonographic renal resistance index in healthy children

The objective of the study was to determine the values of Doppler resistance indices (RIs) in intrarenal arteries in healthy children. Color duplex Doppler sonography of intrarenal arteries was performed in 163 children and 58 adult patients, with the absence of clinical or laboratory pathologic changes of the urinary tract. All patients were classified following results of exploratory data analysis into three age groups: (a) 51 children between 2 and < 6 years of age; (b) 112 children 6–16 years of age; and (c) adults. The RIs were compared between different age groups. The mean RI ± 1 SD values in group 1 were 0.705 ± 0.018 (range 0.67–0.75), in group 2 0.605 ± 0.029 (range 0.55–0.65), and in the adult group 0.604 ± 0.035 (range 0.54–0.68). In the group of the youngest children (group 1), the RIs were significantly higher (p < 0.01) in comparison with the other group of children and the adult group. No statistically significant difference was observed between the group of children 6–16 years of age and the adult group. RI < 0.70 was noted in all children above 6 years of age; however, in younger children, RI ≥ 0.70 was observed in 72.5 % (37 of 51) of children. Resistance index in early childhood was considerably higher as compared with older children and the adult population: Apparently the RI value drops to adult level at approximately 6 years of age. The utilization of a threshold RI value of 0.70 for the increased renal vascular resistance in adults can also be applied to children over 6 years of age. Received: 4 January 2000; Revised: 3 April 2000; Accepted: 4 April 2000     

Current concepts in sonographic diagnosis of fetal renal disease

The fetal kidneys and bladder are usually visible by 15 weeks' gestation on sonograms. The authors present their experience with the diagnosis of renal abnormalities in the fetus.     

Caveats in the sonographic determination of fetal femur length for estimation of gestational age

Irradiation of the orbit is often associated with substantial dose inhomogeneity resulting from the insertion of lens blocks. We postulated that such dose inhomogeneity, which often exceeds 40%, could be halved by the use of two pairs of wedged beams, one angled in the sagittal plane and the other in the commonly employed transverse plane. The sagittal plane is obtained by turning the treatment couch 90 degrees. All beams carried a central-axis lens block and were angled 30 degrees relative to the vertical. Verification of dose distribution was obtained by film dosimetry in a head phantom for central- and off-axis planes. These measurements indicate that significant improvement in dose homogeneity over alternate methods can be achieved with this technique.     

Hypoechoic renal pyramids: sonographic visualization in older children and young adults.

The frequency and degree of visualization of medullary pyramids in a normal population, aged 10-29 years, was analyzed. Hypoechoic pyramids were visualized in 42% of right kidneys in subjects aged 10-18 years and in 27% of subjects aged 19-29 years. Prominently hypoechoic pyramids, mimicking the appearance of neonatal kidneys, were seen in an additional 34% of subjects aged 10-18 years and in 16% aged 19-29 years. Prominent pyramids were present in 50% of subjects with renal cortical echogenicity (RCE) equal to liver, but also in 21% of subjects with RCE less than liver. Our study expands the age at which prominently hypoechoic medullary pyramids can be considered a normal finding. This may relate to recent improvements in ultrasound technology.     

Normal length of fetal kidneys: sonographic study in 397 obstetric patients

This study was done to measure normal lengths of fetal kidneys sonographically during pregnancy. Knowledge of these measurements may allow earlier diagnosis of a variety of abnormalities. The greatest length of each of 498 kidneys in 397 consecutive fetuses between 18 and 41 weeks gestation was measured on sonograms. Gestational ages were determined by last menstrual period and biometry; significant discrepancies led to case exclusion. Abnormal fetuses, twins, offspring of diabetic mothers, and fetuses with renal pelvic dilatation of 4 mm or greater were excluded to avoid any questionable measurements. The results show that mean lengths are greater and confidence intervals are wider than previously reported. Renal lengths are similar to those reported in premature and full-term neonates. Strong correlation exists between renal length and gestational age, determined by biparietal diameter, femoral length, and abdominal circumference, and an average of the three. No significant difference was found between right and left renal lengths in fetuses in whom both kidneys were imaged. Average renal lengths are significantly different when compared across the range of gestational ages (p less than .001). No correlation is seen (r = .00) between parental height or weight and fetal renal length. Our results show that fetal renal lengths are longer than previously reported.     

Second branchial cleft cysts: variability of sonographic appearances in adult cases

BACKGROUND AND PURPOSE: Previous reports have suggested that second branchial cleft cysts (BCCs) appear on sonograms as well-defined, cystic masses with thin walls and posterior enhancement. Previous CT and MR imaging findings, however, have indicated heterogeneity of these masses, and, in our experience, sonography also shows a similar variable appearance. In this communication, we report the cases of 17 patients with second BCCs and document the variability of sonographic patterns. METHODS: The sonograms of 17 adults with second BCCs were reviewed. Only patients with surgical or cytologic evidence of BCCs were included in this study. The features evaluated were the location, internal echogenicity, posterior enhancement, and presence of septa and fistulous tract. RESULTS: Four patterns of second BCCs were identified: anechoic (41%), homogeneously hypoechoic with internal debris (23.5%), pseudosolid (12%), and heterogeneous (23.5%). The majority (70%) showed posterior enhancement. All were situated in their classical location, posterior to the submandibular gland, superficial to the carotid artery and internal jugular vein, and closely related to the medial and anterior margin of the sternomastoid muscle. Fourteen (82%) of the 17 BCCs had imperceptible walls, and all were well defined. For none of the patients was a fistulous tract revealed by sonography; the presence of internal septations was revealed for three patients. CONCLUSION: As previously suggested by CT and MR imaging findings, sonography reinforces that second BCCs in adults are not simple cysts but have a complex sonographic pattern ranging from a typical anechoic to a pseudosolid appearance.     

Observer variability in screen-film mammography versus full-field digital mammography with soft-copy reading

Full-field digital mammography (FFDM) with soft-copy reading is more complex than screen-film mammography (SFM) with hard-copy reading. The aim of this study was to compare inter- and intraobserver variability in SFM versus FFDM of paired mammograms from a breast cancer screening program. Six radiologists interpreted mammograms of 232 cases obtained with both techniques, including 46 cancers, 88 benign lesions, and 98 normals. Image interpretation included BI-RADS categories. A case consisted of standard two-view mammograms of one breast. Images were scored in two sessions separated by 5 weeks. Observer variability was substantial for SFM as well as for FFDM, but overall there was no significant difference between the observer variability at SFM and FFDM. Mean kappa values were lower, indicating less agreement, for microcalcifications compared with masses. The lower observer agreement for microcalcifications, and especially the low intraobserver concordance between the two imaging techniques for three readers, was noticeable. The level of observer agreement might be an indicator of radiologist performance and could confound studies designed to separate diagnostic differences between the two imaging techniques. The results of our study confirm the need for proper training for radiologists starting FFDM with soft-copy reading in breast cancer screening. Presented at ECR, Wien 2006.     

A review of sonographic evaluation of renal transplant complications

In this article, we present an overview of renal transplantation with its complications and discuss the abilities and limitations of ultrasound in evaluating these complications. We included renal transplants performed at our institution between 1993 and 2006 and gathered data on more than 1,000 patients who developed graft dysfunction. We analyzed the ultrasound findings in different posttransplant complications and compared our findings with those in published literature. We present this review article that elaborates and categorizes various transplant complications from an ultrasound perspective. Based on imaging evaluation, the complications of renal transplantation can be divided into four major categories: peri-renal, renal parenchymal, renal collecting system, and renal vascular complications. Common complications included acute tubular necrosis, graft rejection, drug nephrotoxicity, hematoma, lymphocele, urinoma, hydronephrosis, and vascular complications. Ultrasound has a key role in identification and management of most of these complications. However, some parenchymal complications may only be diagnosed on renal biopsy. Ultrasound is a very powerful screening tool to assess renal transplant dysfunction and has a primary role in early diagnosis and management of structural and vascular complications, which may need surgical intervention to save the graft.