Biomedical subjects
Stefan Puig
Publications and source records attributed to Stefan Puig.
Vascular low-flow malformations in children: current concepts for classification, diagnosis and therapy.
Congenital vascular malformations (CVM) are made of dysplastic vessels with no cellular proliferation. Low- or slow-flow malformations (LFM) consist predominantly of venous and/or lymphatic vessels. Correct terminology is necessary for differentiating vascular malformations from tumours such as haemangiomas, in order to prevent ineffective or even adverse therapy. The role of the radiologist in the management of patients is two-fold: making the diagnosis with the use of ultrasound and magnetic resonance imaging, and performing sclerotherapy, which is the treatment of choice. Prior to sclerotherapy, percutaneous phlebography is necessary to visualize the dynamic situation inside the lesion and the flow into the adjacent vascular system. The double-needle technique is a useful therapy option reducing the risk of embolisation of the sclerosing agent. Large lesions might need subsequent surgical treatment. A multidisciplinary approach is substantial for optimal patient management.
Microvessel density is not crucial for scintigraphic visualization of brain tumors using 99mTc-MIBI.
Functional imaging of brain tumors assists biopsy localization, therapy monitoring, and differentiating tumor recurrence from radiation necrosis. Tumor vascularization is a strong prognostic predictor in solid tumors and also a key factor of tracer uptake. However, the relationship of brain tumor vascularization and functional imaging has not yet been investigated sufficiently so far. In the present study, we correlated histologically assessed microvessel density as an objective parameter for brain tumor vascularization with imaging data. Four male patients were studied. After 99mTc-MIBI scintigraphy, all patients had a MRI within 2 weeks. Histology showed microcystic astrocytoma, glioblastoma (n = 2), and anaplastic oligodendroglioma, respectively. Microvessel density was lowest in the microcystic astrocytoma, medium in the glioblastomas, and highest in the anaplastic oligodendroglioma. Scintigraphy visualized only the glioblastomas, but not the microcystic astrocytoma or oligodendroglioma. Our data showed no correlation between tumor microvessel density and 99mTc-MIBI scintigraphy. Thus, we conclude that scintigraphic visualization of brain tumors is not strictly dependent on tumor vascularization.
Articular genus muscle of the knee.
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Acute hemorrhagic respiratory failure caused by Wegener's granulomatosis successfully treated by bronchoalveolar lavage with diluted surfactant.
Wegener's granulomatosis (WG) is an idiopathic inflammatory systemic disease that can occasionally cause an acute respiratory distress syndrome. We report on a 17-year-old girl with Wegener's granulomatosis and acute hemorrhagic respiratory failure successfully treated using bronchoalveolar lavage with diluted porcine surfactant (Curosurf; 4.8 mg/mL) followed by a low-dose bolus of surfactant. The cumulative dose of surfactant was 40 mg/kg BW. The lavage with diluted surfactant and the administration of the bolus were performed with a flexible bronchoscope. The patient was ventilated during the whole procedure, stayed hemodynamically stable and showed only a very short phase of desaturation. The PaO2/FiO2 ratio increased from 54.8 to 62.4 after one hour, to 106 after 17 hours and finally to 280 after four days. The patient was extubated five days after lavage treatment, and almost normal lung function was restored after eight weeks. Bronchoalveolar lavage with diluted surfactant by flexible bronchoscopy allows selective and direct drug administration and removes airway and alveolar debris. The technique reduces the amount of surfactant needed to overcome inhibition and thereby reduces therapy costs. We conclude that this early therapeutic intervention with surfactant might help to avoid an invasive rescue therapy such as extra corporeal membrane oxygenation, thus improving outcome in terms of faster recovery of lung function.
Usefulness of magnetic resonance imaging of cardiac and paracardiac masses.
In this study, magnetic resonance imaging was compared with histology to evaluate the usefulness of magnetic resonance imaging to distinguish malignant from benign cardiac and paracardiac masses in 55 patients. Tumor location, tissue composition, and pericardial or pleural effusion all were identified as key predictors of lesion type. Observers were accurate in the prediction of lesion type (area under curve 0.88 and 0.92), and there was good interobserver variability (Cohen's kappa = 0.64).
US as a primary diagnostic tool in relation to negative appendectomy: six years experience.
PURPOSE: To evaluate the effect of ultrasonography (US) on the rate of appendectomy after false-positive diagnosis of acute appendicitis (negative appendectomy). MATERIALS AND METHODS: Data were analyzed in 736 pediatric patients (mean age, 13.2 years) who had undergone appendectomy between 1995 and 2000. Histologic data were compared in patients who underwent US with those who did not undergo imaging prior to surgery. US was performed by a radiologist or a pediatric surgeon or both. RESULTS: A total of 643 (87.4%) of the 736 pediatric patients underwent preoperative US, and 93 (12.6%) of the 736 did not undergo preoperative US. Of the 736 patients, 97 (13.2%) underwent negative appendectomy. Thirty-four (36.6%) of the 93 patients who underwent appendectomy with no preoperative US and 63 (9.8%) of the 643 patients who underwent preoperative US underwent negative appendectomy. There was a significant association between US and positive appendectomy (P <.001). CONCLUSION: US in pediatric patients suspected of having appendicitis can significantly lower the negative appendectomy rate.
Double-needle sclerotherapy of lymphangiomas and venous angiomas in children: a simple technique to prevent complications.
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Classification of venous malformations in children and implications for sclerotherapy.
OBJECTIVE: The purpose of this work is to present a simple and descriptive classification system for venous malformations (VMs) that may serve as a basis for interventional therapy, and to test its usefulness in a sample of consecutively referred paediatric patients. MATERIALS AND METHODS: The classification system we developed includes four types: type I, isolated malformation without peripheral drainage; type II, malformation that drains into normal veins; type III, malformation that drains into dilated veins; and type IV, malformation that represents dysplastic venous ectasia. The system was prospectively tested using phlebography in a sample of 43 children and adolescents with VMs who were referred for treatment during a 10-month period. Our hypothesis was that the type of VM would determine whether low-risk sclerotherapy was indicated. RESULTS: Thirteen (30%) patients had a type-I VM, 16 (37%) had a type-II, 9 (21%) had a type-III, and 5 (12%) had a type-IV malformation. In more than 90% of patients with a type-I or type-II lesion, sclerotherapy could be performed without any problems. In one third of patients with a type-III VM, sclerotherapy had to be withheld and one of nine (11%) developed a severe complication after therapy. Of the five patients with type-IV lesions, three (60%) had to be excluded from sclerotherapy. CONCLUSIONS: Our initial results indicate that sclerotherapeutic intervention in patients with type-III and type-IV VMs must be carefully considered, while it can be safely performed in low-risk patients with type-I and type-II lesions.
Ultrasound of the appendix in children: is the child too obese?
The negative influence of obesity on the detection rate of the appendix for US in adults has been reported. It has been assumed that obesity is a limiting factor in the detection of the appendix with US in children as well, but this has not yet been proven. The aim of our study was to evaluate whether nutritional condition (defined by the body mass index-for-age percentiles: BMI-FAP) influences the detection of the appendix in children on US. One hundred twenty-six children (65 girls and 61 boys) with a mean age of 11.4 years with clinically suspected acute appendicitis underwent ultrasound on a commercially available high-end machine (HDI 5000, ATL, Bothell, Wash.). The BMI was calculated, and children were divided in three weight groups in accordance with the BMI-FAP, and were correlated with US findings. Evaluation of the three weight groups in accordance with the BMI-FAP demonstrated significant differences ( p=0.04) in the detection of the appendix. There was no statistical significance for the BMI, weight, height, and age solely for the detection of the appendix. In children there is a correlation between the nutritional condition as defined by the BMI-FAP and the detection of the appendix.
Posterior "Nutcracker" phenomenon in a patient with abdominal aortic aneurysm.
We report on a posterior "nutcracker" phenomenon due to an abdominal aortic aneurysm in a patient with a retro-aortic left renal vein. A 71-year-old man with a known abdominal aortic aneurysm presented in the emergency room with mild hematuria and flank pain. Computed tomography angiography revealed an aortic aneurysm, which compressed the left renal vein between the aorta and the vertebral column. Compression of the left renal vein, due to the aorta with consecutive congestion and hematuria as well as flank pain, was previously described as nutcracker phenomenon. In case of a retro-aortic left renal vein, increase of the aortic diameter can lead to compression of the renal vein and furthermore to the classical signs and symptoms of the "nutcracker" phenomenon, even though the aneurysm is not ruptured or there are no aorto-caval or aorto-left renal vein fistulas.
Imaging articular cartilage defects in the ankle joint with 3D fat-suppressed echo planar imaging: comparison with conventional 3D fat-suppressed gradient echo imaging.
PURPOSE: To shorten the examination time for articular cartilage imaging, using a recently developed three-dimensional (3D) multishot echo planar imaging (EPI) sequence with fat saturated (FS), compared to a conventional 3D fat-saturated spoiled gradient echo sequence (3D FS GRE). MATERIAL AND METHODS: There were 32 consecutive patients with ankle joint disorders who underwent magnetic resonance imaging (MRI) in a 1.0-T unit. Hyaline cartilage was imaged with a 3D FS EPI sequence and a 3D FS GRE sequence. Image assessment criteria included lesion conspicuity, contrast between different types of normal tissue, and image artifacts. In addition, contrast-to-noise ratios (CNRs) of cartilage vs. joint fluid and bone marrow were measured. RESULTS: The 3D FS EPI sequence provided a high CNR between cartilage and subchondral bone, similar to that of the 3D FS GRE sequence. The CNR between cartilage and effusion was significantly lower on the 3D EPI sequence due to the higher signal intensity of fluid. Both sequences were equal in lesion detection ability. The image quality of the 3D FS GRE sequence was slightly higher than that of the 3D FS EPI, but the difference was not statistically significant. CONCLUSION: We conclude that the 3D FS EPI sequence is comparable to the 3D FS GRE sequence in the detection of cartilage lesions, with the additional advantage of reduction in scan time by a factor of 4.
Single- and multi-slice spiral computed tomography of the paediatric kidney.
Single- and multi-slice computed tomography (CT) is regarded as the primary imaging tool in traumatology, both in adults and children. For complicated infectious disease and renal tumours, these techniques are recommended only as secondary diagnostic tools. Specifically, multi-slice CT (MSCT) provides excellent spatial resolution, which is a particular advantage for the evaluation of small structures as they are typical in children. However, MSCT offers more information than is required for diagnosis. Therefore, low-dose protocols are necessary for paediatric examinations. The CT dose-index (CTDI(vol)) should not exceed 2 mGy for newborns, 4 mGy for toddlers, 5 mGy for elementary school children, and 8 mGy for adolescents.
Release of toxic metals from button batteries retained in the stomach: An in vitro study.
BACKGROUND: Ingestion of button batteries by children is a rapidly growing problem, and opinions differ on how button batteries distal to the gastroesophageal junction should be managed. The authors therefore performed an experimental study to determine the cumulative load of various toxic elements released from retained button cells in simulated gastric juice. METHODS: Eight different groups of button cells were immersed in simulated gastric juice. Analyzed elements included Al, Ba, Cd, Cr, Cu, Fe, Hg, Li, Mg, Mn, Ni, Pb, Sb, Sn, Sr, Te, TI, V, W; and Zn. Inductively coupled plasma mass spectrometry (ICP-MS) was used to evaluate the residual amounts of elements after 4, 24, 72, and 120 hours. RESULTS: At 4 hours, leakage was seen with almost all batteries, with the levels increasing in a time-dependent manner. The highest detected levels at 4 hours were 1.20 microgram for Cd, 280.51 ng for Hg, and 2.63 microgram for Pb. Dissolution, holes, and defragmentation were seen within 24 to 72 hours. Battery weight loss varied between 22 and 104 mg over the course of the study. CONCLUSIONS: Toxic elements contained in button cells are released quickly in gastric juice. This finding might change the current policy of watchful waiting or conservative management of batteries lodged in the stomach.