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S Delorme

Publications and source records attributed to S Delorme.

At least 19 recordsLinked to original sources
PubMed2007

[Neoadjuvant chemotherapy of breast carcinomas: what post-therapeutic (preoperative) information is provided by quantitative dynamic MRI?].

PURPOSE: The aim of this study was to evaluate whether quantitative changes in contrast enhancement (CE) after neoadjuvant chemotherapy (NC) are associated with histological signs of tumor regression and whether quantitative dynamic MRI (dMRI) is capable of accurately assessing preoperative tumor size compared to mammography (MG) and ultrasound (US). METHODS: Thirty-one patients with breast cancer underwent MRI before and after NC. Dynamic CE was measured using a turbo-FLASH sequence and quantified by a two-compartment model, where two parameters, k(ep) (distribution constant rate) and A (amplitude), were calculated and color mapped. RESULTS: When tumors had signs of histological regression in the operative specimen (n=17) decrease of the parameters A and k(ep) was significantly more marked compared to tumors without regression (n=12). The correlation between tumor size measured by dMRI and histopathology was 0.81 when areas of unspecific CE were included; when they were not included the correlation was 0.66 and tumor size was systematically underestimated. In 26 patients dMRI was retrospectively compared with MG (r=0.51; dMRI, r=0.80) and in 22 patients with US (r=0.60; dMRI, r=0.75). CONCLUSION: Changes in dynamic CE are associated with histological tumor regression. Quantitative dMRI enables a valid assessment of tumor residue and is superior to MG and US. Remaining unspecific CE within the original tumor site should be considered as potentially malignant.

Breast↗
PubMed2006

Applications of MRS in the evaluation of focal malignant brain lesions.

Magnetic resonance spectroscopy (MRS) has clinically been most extensively used for assessing brain disorders, particularly tumors. With 1-H spectroscopy at intermediate echo times, resonances from choline, creatine, N-acetyl-aspartate (NAA), lactate, and free fatty acids can be resolved well enough to assist in diagnosis under routine conditions. Generally, an increased concentration of choline is found in all primary and secondary brain tumors, and the degree of increase correlates with the degree of anaplasia. Further indicators of anaplasia are the presence of lactate, indicating hypoxia, and of fatty acids, indicating necrosis. According to literature, the sensitivity of a combination of proton spectroscopy with contrast-enhanced dynamic susceptibility-weighted imaging for high-grade components in gliomas is better than conventional contrast-enhanced imaging alone. Today, proton spectroscopy is clearly indicated for differentiating radiation-induced damage from recurrences of irradiated brain tumors.

Brain Neoplasms↗
PubMed2006

[Ultrasound contrast media--principles and clinical applications].

This article reviews the technical basics and the application of contrast-enhanced ultrasonography. Ultrasound contrast agents have been evaluated in various organs and have proven to be particularly useful in the detection and characterization of liver lesions. Experiences in small parts (such as breast, or lymph nodes) are so far limited, because only since recently are the technical prerequisites available for contrast-enhanced ultrasound high-frequency transducers. Ultrasound contrast media can be used for functional studies, e. g., of organ or tumor perfusion. Mathematical models were primarily developed for measuring myocardial perfusion and have recently been adapted for studying tumors. In animal experiments as well as in clinical applications, quantitative parameters of tumor perfusion have been evaluated as surrogate parameters for response to radiotherapy, chemotherapy, or treatment with anti-angiogenic agents.

Algorithms↗
PubMed2005

Monitoring of liver metastases after stereotactic radiotherapy using low-MI contrast-enhanced ultrasound--initial results.

The purpose of this study was to monitor liver metastases after radiotherapy using contrast-enhanced ultrasound (CEUS). In 15 patients, follow-up examinations after stereotactic, single-dose radiotherapy were performed using CEUS (low mechanical index (MI), 2.4-ml SonoVue) and computed tomography (CT). Besides tumor size, the enhancement of the liver and the metastases was assessed at the arterial, portal venous, and delayed phases. The sizes of the tumor and of a perifocal liver reaction after radiotherapy measured with CEUS significantly correlated with those measured at CT (r=0.93, p<0.001). CEUS found a significant reduction of the arterial vascularization in treated tumors (p<0.05). In the arterial phase, the perifocal liver tissue was hypervascularized compared to the treated tumor (p<0.001); in the late phase, it was less enhanced than the liver (p<0.001) and more than the tumor (p<0.01). The perifocal liver reaction was also seen in CT, but with a variable enhancement at the arterial (50% hyperdense compared to normal liver tissue), venous, or delayed phase (each with 70% hyperdense reactions). CEUS allows for the assessment of tumor and liver perfusion, in addition to morphological tumor examination, which was comparable with CT. Thus, changes of tumor perfusion, which may indicate tumor response, as well as the perifocal liver reaction after radiotherapy, which must be differentiated from perifocal tumor growth, can be sensitively visualized using CEUS.

Contrast Media↗
PubMed2005

[Vascular imaging with contrast-enhanced sonography for experimental use].

The possibility of employing contrast-enhanced ultrasound for sensitive detection of perfusion has resulted in new forms of application in fundamental medical biological research that go far beyond mere preclinical evaluation of these techniques. This contribution explains the methods for visualization and quantification of perfusion with contrast-enhanced sonography and provides an overview of how these functional examinations have been used to date. The procedure is generally considered indicated when information on tissue perfusion using ultrasound is required. This topic is also gaining increasing clinical interest, e.g., for assessment of myocardial, cerebral, and renal perfusion or for monitoring therapy. Among the various new treatment procedures that have been investigated in animal models with ultrasound, particularly pro-angiogenic and antiangiogenic therapy approaches predict promising new fields for application of contrast-enhanced ultrasound.

Animals↗
PubMed2005

[Teleradiology: economic research analysis of CT investigations in a small hospital].

PURPOSE: To evaluate, discuss and compare economic aspects of teleradiological applications in CT examinations in a small hospital. Scenario (1): CT examination by an extern institution including transport of a patient. Szenario (2): External consultation of an internal CT examination (teleradiology according to ROV). Scenario (3): Complete in-house radiology department. To evaluate economic aspects of teleradiology service providers. MATERIALS AND METHODS: Costs have been separated into fixed and variable costs in a model. Total costs of 500 CT examinations per year have been calculated for the three scenarios. A break-even analysis has been performed to determine the necessary/minimal number of CTs per year for economical advantages. The number of CT consultations for teleradiology service providers to make profit has been calculated. RESULTS: Scenario (1): This is the most cost-effective scenario for 500 CTs per year, but most time-consuming. Beyond 548 CTs per year using a single slice CT and 965 CTs per year using a multislice CT the teleradiology scenario [scenario (2)] is most cost-effective. Beyond 1065 CTs per year an in-house radiology department [scenario (3)] is economically reasonable. On the basis of 30 Euros per CT consultation a teleradiology service providing system will be profitable starting from 322 CT consultations per year. CONCLUSION: Teleradiology applications are economically reasonable in a wide range in small hospitals. CT teleradiology services can also be provided on a cost-effective basis at a reachable number of consultations.

Cost-Benefit Analysis↗
PubMed2005

[Correlation of MRI and histopathology of bone marrow in patients with multiple myeloma].

PURPOSE: To compare MRI findings and histological plasmacellular infiltration of the bone marrow in patients with multiple myeloma (MM). MATERIAL AND METHODS: Twenty-four patients with different stages of MM underwent 1.5T MRI of the pelvic bone before iliac crest punch biopsy. Precontrast T1wSE and STIR and postcontrast (Gd-DTPA) T1wSE-fatsat were acquired using axial slices. Immediately after the biopsy, T1wSE was repeated to locate the biopsy canal. The corresponding region in the examination before punch biopsy was assessed for bone marrow involvement using a three-point score (0: negative, 1: suspect, 2: definite). RESULTS: Two patients were not included because the location of the biopsy canal was unclear. Of 7 patients without histological plasmacellular infiltration, MRI was false positive in one case (suspect). Of 15 patients with histological infiltration, MRI was positive in 10 cases (4 suspect, 6 definite). The T1wSE was positive in 9 cases, STIR in 8 cases, and postcontrast T1wSE-fatsat in 7 cases. In 10 of the 15 patients, the infiltration was histologically graded as low (5 - 20 % of bone marrow). In this group, MRI was only positive in 5 cases (3 suspect, 2 definite). Of five patients with the infiltration histologically graded as high (> 20 % of bone marrow), MRI was positive in all cases (1 suspect, 4 definite). CONCLUSION: Only advanced bone marrow infiltration in MM can be reliably detected by MRI. None of the used sequences proved to be significantly superior or inferior.

Aged↗
PubMed2004

[Noninvasive measurement of relative cerebral blood flow with the blood bolus MRI arterial spin labeling: basic physics and clinical applications].

Knowledge of tumor blood flow is important for diagnosis and follow-up of brain tumors after therapy, especially to discriminate necrosis from tumor recurrence after radiation or chemotherapy. Meanwhile, perfusion and diffusion MRI, besides MR-angiography, are state of the art in stroke imaging. Until now, perfusion imaging was mostly performed using the first-pass dynamic susceptibility-weighted contrast-enhanced (DSC) MRI. The MRI-based arterial spin labeling technique (ASL) is a novel approach for measuring relative cerebral blood flow (rCBF) without using extrinsic contrast agents, by labeling spins of flowing arterial blood as intrinsic contrast agent. This article describes physical basics of ASL and shows clinical examples in neuroimaging such as in meningeoma, glioblastoma, oligodendroglioma, and cerebral ischemia, using the Q2TIPS ASL technique. Gray matter is clearly visible, while the observed white matter signal obtained by Q2TIPS is only slightly higher than background noise. Venous blood causes artefacts in the sagittal sinus and other large superficial veins in the subarachnoid space. Meningeoma and glioblastoma show elevated rCBF, whereas oligodendroglioma and cerebral ischemia have reduced rCBF values. Arterial-spin-labeling techniques are noninvasive tools for measuring rCBF within 5 min, using a standard MRI scanner.

Blood Flow Velocity↗
PubMed2004

[Breast cancer. Sonography and magnetic resonance mammography].

Breast cancer is the most common malignant tumor in women: Almost 10% will suffer from breast cancer during their life; almost half of these will die of it. The spectrum of radiologic methods for diagnosing breast cancer is wide, including X-ray mammography, ultrasound, magnetic resonance mammography, and minimally invasive biopsies. This second part of two covers ultrasound of the breast and magnetic resonance mammography.

Biopsy, Needle↗
PubMed2004

Rings, slings and other vascular abnormalities. Ultrafast computed tomography and magnetic resonance angiography in pediatric cardiology.

Ultrafast CT and MR angiography are noninvasive, accurate and robust techniques for preoperative diagnosis and planning of congenital heart disease and vascular abnormalities in pediatric patients. While they seem to be equivalent to conventional catheter angiocardiography for detecting vascular abnormalities, they are more accurate for the diagnosis of potentially life-threatening complications, such as tracheal, bronchial or esophageal compression. The value of ultrafast CT and MR angiography is demonstrated in 22 pediatric patients with vascular rings, slings and other vascular abnormalities.

Angiography↗
PubMed2004

[Dynamic MRI of the bone marrow for monitoring multiple myeloma during treatment with thalidomide as monotherapy or in combination with CED chemotherapy].

PURPOSE: To quantify changes of bone marrow microcirculation in multiple myeloma (MM) using contrast enhanced dynamic MRI (dMRI) during thalidomide as antiangiogenic monotherapy or in combination with chemotherapy (cyclophosphamide, etoposide, dexamethasone). MATERIALS AND METHODS: The study includes 63 patients with refractory or relapsed MM, who underwent dMRI with high temporal resolution (T1w-turboFLASH) of the lumbar spine before and following treatment. The contrast uptake was quantified using a two compartment model with the output parameters amplitude and k (ep) (exchange rate constant). The evaluation considered the initial dMRI finding (pathological or non-pathological) and the clinical therapeutic response (response or no response). RESULTS: During monotherapy with thalidomide (n = 38), no significant changes of the dMRI parameters were found, even when considering the initial dMRI finding (positive n = 22) and the therapeutic response (responder n = 14). The combination with chemotherapy (n = 25) had a significant reduction of k (ep) (p = 0.01) in 18 patients with positive initial dMRI finding and therapeutic response. Reduction of the amplitude was seen in most cases, but in the end without any significance (p = 0.09). CONCLUSION: dMRI can quantify significant changes of bone marrow microcirculation solely during treatment with thalidomide combined with chemotherapy, not with thalidomide alone.

Administration, Oral↗
PubMed2004

[Diagnosis and staging of pancreatic carcinoma: MRI versus multislice-CT -- a prospective study].

PURPOSE: To evaluate multislice-CT versus MRI in the diagnosis and staging of pancreatic carcinoma in a prospective multi-reader analysis. MATERIALS AND METHODS: Fifty patients with suspected pancreatic carcinoma underwent both multislice-CT (4-Row, "hydro-technique") and state-of-the-art MRI (two 1.5 T units). In correlation with histopathologic findings or in case of a non-lesion diagnosis by follow-up (6-month interval), we evaluated MRI versus CT in a multi-reader analysis (2 reader pairs) for: 1. diagnostic quality; 2. examination time; 3. accuracy of potential resectability; 4. kappa analysis of observer variations; and 5. overall diagnostic reliability. RESULTS: A total of 28 lesions (n = 22 malignant, n = 6 benign) were present in the cohort group versus 22 patients without a focal lesion (n = 10 pancreatitis, n = 12 no tumor). For lesion detection, CT had a sensitivity of 100/89 % (reader pair 1/2) and specificity of 77 %, and MRI had a sensitivity of 75/89 % and specificity of 77/73 %. For the subgroup of adenocarcinomas of the pancreas (n = 17), we found a sensitivity of 100 % and a specificity of 61 % for CT versus a sensitivity of 82/94 % and a specificity of 67/61 % for MRI. The accuracy for determining the resectability was 91/82 % for CT and 90/82 % for MRI. The kappa analysis showed a good correlation for CT (0.71) and a moderate correlation of both groups for MRI (0.49). CONCLUSION: CT and MRI showed comparable results in the detection of pancreatic carcinomas as well as in the determination of resectability. Chronic pancreatitis as a "tumor-like-lesion" was the major factor of a missed diagnosis. The results of multi-reader analysis for both reading groups were almost identical with a moderate to good kappa correlation. There is no reason to prefer MRI (more expensive) over CT for patients with the presumptive diagnosis of pancreatic cancer.

Adenocarcinoma↗
PubMed2004

Morpho-functional visualization of dynamic MR-mammography.

In view of an increasing use of breast MRI supplementing X-ray mammography, the purpose of this study was the development of a method for fast and efficient analysis of dynamic MR image series of the female breast. The image data sets were acquired with a saturation-recovery-turbo-FLASH sequence facilitating the detection of the kinetics of the contrast agent concentration in the whole breast with a high temporal and spatial resolution. In addition, a morphological 3D-FLASH data set was acquired. The dynamic image data sets were analyzed by tracer kinetic modeling in order to describe the physiological processes underlying the contrast enhancement in mathematical terms and thus enable the estimation of functional tissue specific parameters, reflecting the status of microcirculation. To display morphological and functional tissue information simultaneously, a multidimensional real-time visualization system (using 3D-texture mapping) was developed, which enables a practical and intuitive human-computer interface in virtual reality. The spatially differentiated representation of the computed functional tissue parameters superimposed on the anatomical information offers several possibilities: improved discernibility of contrast enhancement, inspection of the data volume in 3D-space and localization of lesions in space and thus fast and more natural recognition of topological coherencies. In a feasibility study, it could be demonstrated that multidimensional visualization of contrast enhancement in virtual reality is practical. Especially, detection and localization of multiple breast lesions may be an important application

Breast Neoplasms↗
PubMed2003

[Diagnosis of hyperparathyroidism].

AIM: To preoperatively localize enlarged parathyroid glands in patients with hyperparathyroidism (HPT). METHODS: Besides clinical and biochemical workup, high-resolution ultrasonography (US) is the most commonly used imaging method.Additionally,Tc-99m-MIBI scintigraphy in subtraction or biphasic technique, computed tomography (CT) and magnetic resonance imaging (MRI) are used. RESULTS: US fails to detect a minimum of 10% of enlarged parathyroid glands,most commonly due to ectopic location, or difficult examination conditions, such as nodular goiter or previous surgery. If attempted US localization is unsuccessful, multiphase scintigraphy, using Tc-99m-sestamibi, can help to locate ectopic adenomas in the mediastinum. With SPECT, ademomas can be found which escape detection on planar scans due to their small size. With combined use of US and scintigraphy, a correct localization of parathyroid adenomas is possible in up to 90%. CT and MRI are of limited value due to their low specificity. CONCLUSION: For newly diagnosed hyperparathyroidism, high-resolution US is the method of choice for localizing parathyroid adenomas. If ultrasound fails to detect a lesion, Tc-99m-MIBI scintigraphy is recommended. In patients scheduled for re-operation for recurrent or persistent HPT, a preoperative detection of a parathyroid adenoma should be attempted whenever possible, in order to minimize the extent of surgery. The role of CT or MRI is mainly to help to better anatomically localize a suspected adenoma previously detected with scintigraphy.

Adenoma↗
PubMed2003

[Monitoring of irradiated brain metastases using MR perfusion imaging and 1H MR spectroscopy].

PURPOSE: In follow-up examinations of irradiated brain metastases conventional contrast-enhanced morphological MR imaging is often unable to distinguish between transient radiation effects, radionecrosis,and tumor recurrence. To evaluate changes of relative cerebral blood flow (rCBF) in irradiated brain metastases arterial spin-labeling techniques (ASL) were applied and compared to the outcome of (1)H MR spectroscopy and spectroscopic imaging ((1)H MRS, SI). PATIENTS AND METHODS: In 2 patients follow-up examinations of irradiated brain metastases were performed on a 1.5-T tomograph (average single dose: 20 Gy/80% isodose). Relative CBF values of gray matter (GM), white matter (WM),and metastases (Met) were measured by means of the ASL techniques ITS-FAIR and Q2TIPS. (1)H MRS was performed with PRESS 1500/135. RESULTS: In both patients with initially hyperperfused metastases (Met/GM >1) the reduction of rCBF after stereotactic radiosurgery indicated response to treatment--even if the contrast-enhancing region increased--while increasing rCBF values indicated tumor progression. The findings were confirmed by (1)H MRS, SI and subsequent follow-up. CONCLUSION: The ASL techniques ITS-FAIR and Q2TIPS are able to monitor changes of rCBF in irradiated brain metastases. The two cases imply a possible role for ASL-MR perfusion imaging and (1)H MR spectroscopy in differentiating radiation effects from tumor progression.

Aged↗