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Marilyn J Siegel

Publications and source records attributed to Marilyn J Siegel.

At least 19 recordsLinked to original sources
PubMed2005

Which MRI sequence of the spine best reveals bone-marrow metastases of neuroblastoma?

BACKGROUND: MRI is an effective tool in evaluating bone marrow metastases. However, no study has defined which MRI sequences or image characteristics best correlate with bone-marrow metastases in neuroblastoma. OBJECTIVE: To identify and refine MRI criteria and sequence selection for the diagnosis of bone-marrow metastases in children with neuroblastoma. MATERIALS AND METHODS: Ninety-one children (mean age: 3.2 years; standard deviation: 2.8 years) enrolled in the RDOG IV study participated in our study. Forty-five children had bone metastases determined by bone-marrow aspiration or biopsy (n=4), radionuclide imaging (n=2), or both (n=39). Spine lesions were characterized using coronal T1-weighted (T1W) sagittal short tau inversion recovery (STIR) and coronal gadolinium-enhanced T1-weighted (GAD) MR sequences. Contingency table analysis was performed to determine which MRI sequences and characteristics were associated with metastases. The MRI criteria for metastatic disease were then developed for each imaging sequence. The sensitivity, specificity, predictive values, and accuracy of these criteria were determined for the whole group, children younger than 12 months old, and children 12 months and older. RESULTS: The MR characteristics that had significant (P<or=0.05) associations with metastases were homogeneous low T1-signal intensity, homogeneous high STIR-signal intensity, and heterogeneous pattern on T1, STIR, or GAD. Homogeneous low T1-signal had the highest sensitivity (88%), but a specificity of 62% for detecting metastases. A heterogeneous pattern on GAD was highly specific (97%), but relatively insensitive (65%) for detecting metastases. These MR characteristics were most accurate in children 12 months and older. CONCLUSION: The combination of non-contrast-enhanced T1W and GAD sequences can be used to determine the presence of spinal metastases in children with neuroblastoma, particularly those children who are 1 year and older.

Bone Marrow Neoplasms↗
PubMed2005

Pediatric CT angiography.

Advances in CT technology are having profound impact on imaging children and have made CT angiography possible even in neonates. Even with the tiny anatomy of neonates, small volumes of contrast material, and small venous access catheters, successful CT angiography can be performed with attention to detail. Meticulous attention to patient preparation, the proper selection of technical factors, and optimal delivery of contrast material are crucial. Data post-processing and the creation of 3-D reconstructions are also essential in establishing a correct diagnosis. The applications of CT angiography are different in children than in adults and most applications in children involve assessment of congenital and postoperative vascular and cardiac diseases. The use of CT angiography offers the opportunity to eliminate the long periods of sedation associated with MR and reduce the radiation exposure associated with conventional angiography. Generally, the benefits of CT angiography in children outweigh the risk, namely that of radiation exposure. However, care must still be taken to minimize the radiation exposure.

Angiography↗
PubMed2004

Compositional analysis of muscle in boys with Duchenne muscular dystrophy using MR imaging.

OBJECTIVE: Boys with Duchenne muscular dystrophy (DMD) present by age 5 years with weakness and, untreated, stop walking unaided by age 10 or 11 years. We used magnetic resonance (MR) imaging to study age-related changes in the composition and distribution of diseased muscles. DESIGN AND PATIENTS: Eleven boys (mean 7.1+/-1.6 years) with DMD underwent clinical and MR examinations. Quantitative muscle strength and timed functional testing was performed. Thigh muscles were scanned at three levels (hip, mid-thigh, and knee) using T1-weighted spin echo and short-tau inversion recovery (STIR) sequences. Outcome measures included intramuscular fatty infiltration, intermuscle fat deposition, edema, and muscle size. RESULTS: Ten boys completed the study. Older boys demonstrated more prominent fatty infiltration of muscles. Fatty infiltration occurred in a characteristic pattern with the gluteus and adductor magnus muscles most commonly involved and the gracilis most commonly spared. Similarly, patchy increases in free water content suggested a pattern of intramuscular edema or inflammation. Atrophy occurred in muscles heavily infiltrated with fat, and true hypertrophy selectively occurred in those that were spared. CONCLUSIONS: While fibrofatty changes have been described in DMD, this study further defines differential involvement and additionally suggests widespread edema or inflammation. Improved imaging techniques to quantify the degree and distribution of these changes may provide a basis for exploring mechanisms of action of medications and perhaps another means for selecting treatment regimens and monitoring their effects.

Adipose Tissue↗
PubMed2004

Radiation dose and image quality in pediatric CT: effect of technical factors and phantom size and shape.

PURPOSE: To evaluate effects of varying tube current and voltage on radiation dose, image noise, and image contrast with different phantom sizes and shapes. MATERIALS AND METHODS: Four round lucite phantoms with 8-32-cm diameters were scanned with multi-detector row computed tomography (CT) and 80-120 kVp. Radiation dose was based on CT dose index, image noise, and iodine contrast and measured with constant and variable tube currents that were age appropriate for each tube voltage. Radiation dose and image noise and contrast were compared in round and oval 24-cm phantoms. For various combinations of technical factors and phantom sizes and shapes, percentage differences were calculated for radiation dose and image noise and contrast. Associations between tube voltage and radiation dose, image noise, and image contrast in round and oval phantoms were determined by fitting second-degree polynomials to data. Differences in radiation dose and image noise and contrast, which were attributable to differences in tube voltage, were tested with paired t tests. RESULTS: With 165-mAs tube current, radiation doses with 140- and 80-kVp tube voltages were 103% ([41.9 mGy - 20.6 mGy]/20.6 mGy) and 58% ([10.2 mGy - 4.2 mGy]/10.1 mGy) higher in the 8-cm phantom than in the 32-cm phantom. When tube current was adapted for phantom size, radiation dose at 80 kVp in the 8-cm phantom was reduced by 82% ([10.1 mGy - 1.8 mGy]/10.1 mGy). In the 8-cm phantom, tube voltage was decreased from 120 to 80 kVp and tube current remained at 165 mAs, resulting in a 68% noise increase ([3.1 HU - 1.8 HU]/1.8 HU). With variable tube current, 80-kVp tube voltage in the 8-cm phantom led to a 138% noise increase ([7.3 HU - 3.1 HU]/3.1 HU). With reduced tube voltage, image contrast increased. In the 8-cm phantom, with a constant 165-mAs tube current and a decrease in tube voltage from 120 to 80 kVp, there was a 35% ([333 HU - 217 HU]/333 HU) increase in contrast. No difference was noted in radiation dose or noise between round and oval phantoms (P = .604 and P = .06, respectively), but a small statistically significant difference (1%) in contrast attenuation was demonstrated (P = .025). CONCLUSION: Reduced tube voltage for pediatric contrast material-enhanced CT reduces radiation dose and maintains image contrast. Image noise increases, but the effect is minimal in smaller phantoms. An additional reduction in tube current further reduces radiation dose.

Phantoms, Imaging↗
PubMed2004

Congenital cystic adenomatoid malformation connected to an extralobar pulmonary sequestration in the contralateral chest: common origin?

Extralobar pulmonary sequestration (ELS) and congenital cystic adenomatoid malformation have been reported to coexist in several variations. This suggests a common embryologic origin. A 6-month-old boy presented with a history of recurrent pneumonias. The patient was diagnosed with a right lower lobe congenital cystic adenomatoid malformation (CCAM) and a left lower lobe ELS/CCAM. The diagnosis was made with the aid of a multidetector computed tomography (CT). Three-dimensional CT reconstruction showed the presence of a right lower lobe CCAM, a left lower ELS with an aberrant arterial supply from the celiac axis, and possible venous drainage into the right CCAM. The patient underwent a right thoracotomy. Intraoperatively, the lesions were discovered to be connected by a band of tissue. The right lower lobe CCAM and the left ELS were removed from the right chest. Histologic analysis confirmed the presence of a CCAM within the right lower lobe. The ELS had involvement of a type II CCAM within the sequestration. The connection between the right CCAM and left ELS/CCAM showed an anomalous conducting airway, anomalous vein, and anomalous artery connecting the 2 lesions. The authors present the first case of a CCAM connected to an ELS/CCAM in the contralateral hemithorax. The unique anatomic configuration of these lesions suggests a common embryologic origin of ELS and CCAM.

Bronchopulmonary Sequestration↗
PubMed2004

Amplatzer atrial septal defect occluder for pediatric patients: radiographic appearance.

PURPOSE: To describe the chest radiographic appearance of the Amplatzer septal occluder (ASO) (AGA Medical Corporation, Golden Valley, Minn) for atrial septal defects (ASDs) in pediatric patients. MATERIALS AND METHODS: Two radiologists independently reviewed frontal and lateral chest radiographs obtained in young patients 24 hours after transcatheter ASD closure with the ASO. The appearance (flat disks or dots) and location of the ASO were recorded. The location was related to that of a thoracic vertebral body on frontal and lateral chest radiographs and to a line drawn between the anterior margin of the right hilum and the posterior margin of the inferior vena cava (hilar-caval line) on lateral radiographs; this line corresponded to the expected position of the interatrial septum. The relationship between ASO appearance and patient age was assessed with logistic regression and cumulative probability plots. RESULTS: Sixty-eight pediatric patients (age range, 1 month to 18 years; mean age, 4.2 years; 24 boys and 44 girls) were included. On frontal radiographs, the ASO center projected between T7 and T9, either to the right of or over the spinous processes of the vertebral body. On lateral radiographs, the ASO projected over (n = 66) or anterior to (n = 2) the hilar-caval line. On frontal radiographs, it appeared as one or two flat disks (n = 61) or as two metallic dots (n = 7). On lateral radiographs, it appeared as two flat disks (n = 54) or as two metallic dots (n = 14). The relationship between increasing patient age and the metallic dot appearance on frontal and lateral radiographs and on the combination of frontal and lateral radiographs was highly significant in each case (P < .001, likelihood ratio chi(2) test), with r(2) values of 0.35, 0.20, and 0.28, respectively. ASDs were successfully occluded with the ASO in all patients except one, in whom trivial shunting was seen at 12-month follow-up. CONCLUSION: The ASO in pediatric patients has a characteristic radiographic appearance when properly positioned.

Adolescent↗
PubMed2004

MDCT evaluation of thoracic aortic anomalies in pediatric patients and young adults: comparison of axial, multiplanar, and 3D images.

OBJECTIVE: The objective of our study was to compare accuracies of axial, multiplanar, and 3D volume-rendered images in the diagnosis of thoracic aortic anomalies in pediatric patients and young adults. MATERIALS AND METHODS: Fourteen patients, 17 days to 20 years old, with thoracic aortic anomalies underwent MDCT using axial, multiplanar, and 3D volume-rendering imaging. All images were reviewed by three radiologists for position of the aortic arch, coarctation, vascular compression of the airway, collateral vessel formation, and aortopulmonary shunts (patent ductus arteriosus). Final diagnosis was determined by echocardiography, conventional angiography, bronchoscopy, or surgery. Diagnostic accuracy, sensitivity, and interobserver agreement were evaluated. RESULTS: Average accuracies (average of the three observers for a correct diagnosis) were greater than or equal to 96% for diagnoses of aortic position and airway narrowing on all image types. For the diagnosis of coarctation, average sensitivities (average of the three observers for a true diagnosis) were 73% for axial, 100% for multiplanar, and 100% for 3D volume-rendered images. For the diagnosis of patent ductus arteriosus, average sensitivities were 78% for axial, 94% for multiplanar, and 89% for 3D volume-rendered images. No patients in this study had collateral vessel formation. For the diagnosis of absence of collateral vessel formation, average sensitivities were 100% for axial, 100% for multiplanar, and 100% for 3D volume-rendered images. There were no significant statistical differences in diagnostic performances, agreement with truth, or confidence scores among observers or imaging formats (p > 0.05). CONCLUSION: Axial, multiplanar, and 3D volume-rendered images serve equally well as methods for assessing the side of the aorta to diagnose anomalies. For evaluation of coarctation and patent ductus arteriosus, multiplanar and 3D volume-rendered images perform slightly better than axial images.

Adolescent↗
PubMed2004

Evaluation of angioarchitecture of pulmonary sequestration in pediatric patients using 3D MDCT angiography.

OBJECTIVE: The goal of this study was to show the ability of 3D MDCT angiography to display the arterial and venous vascular anatomy of pulmonary sequestration in children. CONCLUSION: MDCT angiography with 3D rendering shows the anomalous feeding artery and the draining veins that allow a diagnosis of pulmonary sequestration. These features may prove useful in distinguishing intra- and extralobar sequestration and in surgical planning.

Angiography↗
PubMed2003

Multiplanar and three-dimensional multi-detector row CT of thoracic vessels and airways in the pediatric population.

Multi-detector row computed tomography (CT) has changed the approach to imaging of thoracic anatomy and disease in the pediatric population. At the author's institution, multi-detector row CT with multiplanar and three-dimensional reconstruction has become an important examination in the evaluation of systemic and pulmonary vasculature and the tracheobronchial tree. In some clinical situations, multi-detector row CT with reformatted images is obviating conventional angiography, which is associated with higher radiation doses and longer sedation times. Although multi-detector row CT with multiplanar and three-dimensional reconstruction is expanding the applications of CT of the thorax, its role as a diagnostic tool still needs to be better defined. The purposes of this article are to describe how to perform multi-detector row CT with multiplanar and three-dimensional reconstruction in young patients, to discuss various reconstruction techniques available, and to discuss applications in the evaluation of vascular and airways diseases.

Aortic Dissection↗
PubMed2003

Radiologic findings of 2 commonly used cardiac septal occluders with clinical correlation.

Transcatheter closure of an atrial septal defect, patent foramen ovale, or post-myocardial infarction ventricular septal defect has become a safe and effective alternative to medical and surgical therapy. Although the use of transcatheter closure of septal defects is becoming increasingly more popular, there are few reports of the radiographic appearance of the closure devices. We report the chest radiographic findings in 36 patients after transcatheter closure of septal defects with Amplatzer or CardioSEAL occluders in an effort to aid radiologists in recognizing the appearances of these devices and enable them to confirm proper positioning.

Adolescent↗
PubMed2003

CT of posttransplantation lymphoproliferative disorder in pediatric recipients of lung allograft.

OBJECTIVE: The purpose of this study was to determine the CT and clinical findings of posttransplantation lymphoproliferative disorder in pediatric lung allograft recipients. MATERIALS AND METHODS: We reviewed the medical records and CT examinations of 260 lung transplantations in pediatric patients and found 26 recipients who had 29 episodes of histologically proven posttransplantation lymphoproliferative disorder. The clinical and CT features of the disease, the time to diagnosis, and the outcomes were assessed. RESULTS: The clinical presentation of posttransplantation lymphoproliferative disorder varied from asymptomatic pulmonary nodules (14/29 [48%]) detected on chest CT to specific (organ-related) and nonspecific symptoms (15/29 [52%]). Intrathoracic posttransplantation lymphoproliferative disorder occurred in 20 (69%) of 29 cases and manifested as multiple pulmonary nodules (n = 17), alveolar infiltrates (n = 2), and combined nodules and infiltrates (n = 1). In eight (28%) of 29 cases, there was extraparenchymal disease, including adenopathy, pleural effusion, and esophageal thickening and erosions. Extrathoracic posttransplantation lymphoproliferative disorder occurred in 13 cases and involved the abdomen (n = 10), paranasal sinuses (n = 2), and brain (n = 1). In the abdomen, extranodal disease was more common than nodal disease and presented as bowel wall thickening, focal mass lesions, and splenomegaly. In 18 of 29 episodes of posttransplantation lymphoproliferative disorder, the histologic diagnosis was lymphoma. The median time to diagnosis after transplantation for the 29 episodes of posttransplantation lymphoproliferative disorder was 10 months. Thirteen of the 26 patients died. The median time of survival after the diagnosis of posttransplantation lymphoproliferative disorder was 17 months. CONCLUSION: Posttransplantation lymphoproliferative disorder in pediatric lung transplant recipients occurs with relatively high frequency in both the chest and abdomen, tends to have lymphomatous features, and results in substantial mortality rates.

Adolescent↗
PubMed2002

Magnetic resonance imaging of nongynecologic pelvic masses in children.

Pelvic neoplasms can arise from the genitourinary tract, gonads, soft tissues, or bone. The role of imaging is to confirm the presence of tumor, determine the site of origin, delineate the extent for staging and treatment planning, and serve as a baseline for monitoring response to therapy. MR imaging is well suited for the characterization and staging of pediatric pelvic tumors. This article reviews the imaging findings and staging evaluation of the common nongynecologic neoplasms in children. Prostatic, bladder, gonadal, and sacrococcygeal tumors are discussed. Gynecologic tumors are discussed elsewhere in this issue.

Adolescent↗
PubMed2002

Magnetic resonance imaging of the adolescent female pelvis.

MR imaging is well suited to evaluation of the pelvis. Ultrasonography remains the study of choice for the initial evaluation of a suspected gynecologic mass. MR imaging and computed tomography remain problem-solving tools that can help to characterize masses and stage gynecologic malignancies. MR imaging has the advantage of higher soft tissue contrast compared with computed tomography. This article reviews the MR findings of congenital anomalies and masses of the adnexa and uterus in adolescent girls.

Adolescent↗