Acute retroperitoneal hemorrhage complicating a xanthogranulomatous pyelonephritis.
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Adult↗
Biomedical subjects
Alain Luciani
Publications and source records attributed to Alain Luciani.
Adenocarcinomas of unknown primary (ACUP) of the mediastinum mimicking lymphoma: CT findings at diagnosis and follow-up.
OBJECTIVE: To describe the computed tomography (CT) features at diagnosis and after treatment of adenocarcinoma of unknown primary (ACUP) mimicking lymphoma of the mediastinum. METHODS: Fifteen patients with pathologically proven ACUP and with primarily mediastinal involvement were initially referred to the Hematologic Department of our institution with a suspected diagnosis of lymphoma, and accounted for our study population. Presenting symptoms and baseline biological values were analyzed. All thoraco-abdominal CT studies were reviewed for the location and size of the mediastinal involvement and associated findings. Follow-up chest CT was performed in 14 patients after radiotherapy, chemotherapy or surgical treatment. RESULTS: The most frequent CT feature was a large anterior and middle mediastinal mass (67%), with no calcification. Associated findings included the presence of lung nodules (40%), compression of large mediastinal vessels (33%) and pleural effusion (27%). Follow-up CT, performed in 14 cases, suggested partial or complete responses in 7 patients (50%) 4 weeks after the treatment onset. CONCLUSIONS: Mediastinal ACUP is a differential diagnosis of large mediastinal masses and is frequently associated with lung nodules and mediastinal vascular compression.
Adenocarcinoma↗
Lymph node imaging: basic principles.
Lymph nodes are involved in a wide variety of diseases, particularly in cancer. In the latter, precise nodal staging is essential to guide therapeutic options and to determine prognosis. For long, imaging of the lymphatic system has been limited to lymph vessel,especially via the exclusive use of conventional lymphography, at the expense of invasive procedures and patient's discomfort. Three main technical advances, however, have recently completed the clinical armamentarium for lymph node imaging: first, the refinement of cross sectional imaging, i.e. CT and MRI, combined or not with dedicated contrast agents, has progressively replaced conventional lymphography in oncology situations; second, the development of intra-operative sentinel node mapping has profoundly modified the diagnostic and therapeutic procedures in several cancer situations, mostly melanoma and breast cancer; finally, the increased availability of functional imaging, especially through the use of FDG-PET, has greatly contributed to the accuracy improvement of nodal metastases identification. The aim of this review will thus be to briefly review the anatomy and physiology of the lymphatic systems and to overview the basic principles of up-to-date lymph node imaging.
Contrast Media↗
Quantitative CT analysis for assessing response in lymphoma (Cheson's criteria).
Standardized CT-based criteria used for lymphoma staging and follow-up and the current role of FDG-PET are reviewed. The current CT-based International Workshop Criteria (IWC) still have the main advantage of representing standardized criteria allowing comparability of clinical trials in patients with lymphoma. However, functional imaging with integrated IWC and FDG-PET provide more accurate response assessment, and challenge the current paradigm. Although integration of FDG-PET in IWC requires validation in a prospective trial with a large number of patients, new long-term clinical and therapeutic trials probably need to be designed using these new and hopefully standardized functional criteria. This potentially could allow a more risk-adapted approach to the treatment of aggressive lymphoma: intensive (reinforced) therapies for non-responders vs. less intensive therapies for good responders with the main goal of improved clinical outcome.
Fluorodeoxyglucose F18↗
MRI and PET in monitoring response in lymphoma.
The potential of FDG-PET and MRI in monitoring response to treatment in lymphoma is reviewed. Both FDG-PET and MRI can provide whole body imaging. Both also share the advantage of combining functional and anatomical information. At present, hybrid FDG-PET and MDCT is the best technique for monitoring response to treatment, especially early response to treatment. Early assessment of response to treatment has the potential to tailor therapy. MR imaging is useful especially in assessing bone marrow and central nervous system involvement.
Contrast Media↗
Placental perfusion MR imaging with contrast agents in a mouse model.
PURPOSE: To quantitatively analyze placental perfusion by using magnetic resonance (MR) imaging with contrast agents in a mouse model. MATERIALS AND METHODS: Study was conducted according to French law and in full compliance with National Institutes of Health recommendations for animal care. Thirty-six pregnant Balb/c mice at 16 days of gestation were injected intravenously with either a conventional or macromolecular gadolinium chelate, and 1.5-T single-section T1-weighted two-dimensional fast spoiled gradient-echo sequential MR imaging was then performed for 14 minutes. Images were analyzed qualitatively, and parametric map analysis was performed in the resultant 25 mice included in the study. Signal intensity was measured in maternal left ventricle (input function), placenta, and fetus on all images. After converting signal intensity into contrast agent tissue concentrations, a three-compartment model was developed with compartmental and numeric modeling software. Placental perfusion was calculated for conventional (n = 12) and macromolecular (n = 13) gadolinium chelates. Finally, placental and fetal gadolinium concentrations were assayed by means of atomic emission spectrophotometry (n = 15). Perfusion values and placental and fetal gadolinium concentrations for conventional and macromolecular chelates were compared by using an unpaired t test. RESULTS: Based on a constant transfer parameter, estimated placental perfusion did not differ between procedures with conventional and macromolecular gadolinium chelates (0.99 mL/min/g +/- 0.5 [standard deviation] and 1.28 mL/min/g +/- 0.6, respectively, P = .22). Likewise, mean placental gadolinium concentrations did not differ after injection of conventional and macromolecular chelates. In contrast, mean fetal gadolinium concentration was 9.83 micromol/L after conventional chelate injection and below detection limit after macromolecular chelate injection. CONCLUSION: Placental perfusion can be calculated by using dynamic contrast-enhanced MR imaging, as shown in this mouse model.
Animals↗
Assessment of critical limb ischemia in patients with diabetes: comparison of MR angiography and digital subtraction angiography.
OBJECTIVE: The purpose of our study was to evaluate the diagnostic accuracy of hybrid MR angiography by comparison with digital subtraction angiography (DSA) in diabetic patients with critical limb ischemia. SUBJECTS AND METHODS: Thirty-one patients prospectively underwent both hybrid MR angiography and DSA. The hybrid MR angiography study consisted of high-resolution MR angiography of a single calf and foot using a contrast-enhanced 3D gradient-echo volumetric interpolated breath-hold examination with surface coils, followed by three-station bolus chase MR angiography with a dedicated peripheral vascular coil. Two blinded reviewers separately analyzed maximum-intensity-projection hybrid MR angiograms and DSA images. The peripheral vessels were divided into 10 anatomic segments for review. The status of each segment was graded as normal, stenosis less than 50% in diameter, stenosis greater than 50%, or occluded. The sensitivity and specificity of hybrid MR angiography were determined using DSA as the gold standard. Treatment options were considered separately from the results of each examination. RESULTS: Among 310 analyzed segments, the sensitivities of hybrid MR angiography for stenosis and occlusion were, respectively, 95% and 95% for reviewer 1 and 96% and 90% for reviewer 2. The specificities of hybrid MR angiography for stenosis and occlusion were, respectively, 98% and 98% for reviewer 1 and 98% and 99% for reviewer 2. In 25 patients (81%), the quality of bolus chase MR angiography images was insufficient to assess runoff arteries. All treatments proposed on the basis of DSA findings were endorsed by hybrid MR angiography findings. Eleven more treatments were formulated on the basis of hybrid MR angiography findings. Of these, four were due to overestimation of stenosis on MR angiography and seven were due to the detection of patent infrageniculate arteries on hybrid MR angiography that were not detected on DSA. CONCLUSION: Hybrid MR angiography depicts runoff arteries not seen on DSA. Hybrid MR angiography may be useful for treatment planning in selected diabetic patients with critical limb ischemia.
Adult↗
Imaging the lymphatic system: possibilities and clinical applications.
The lymphatic system is anatomically complex and difficult to image. Lymph ducts are responsible for the drainage of part of the body's interstitial fluid. Lymph nodes account for the enrichment of lymph fluid, and can be involved in a large variety of diseases, especially cancer. For a long time, lymphatic imaging was limited to the sole use of conventional lymphography involving invasive procedures and patient discomfort. New contrast agents and techniques in ultrasound, nuclear medicine, and MR imaging are now available for imaging of both the lymphatic vessels and the lymph nodes. The objective of this review is to discuss the different imaging modalities of the lymphatic system, with a special focus on the new possibilities of lymphatic imaging including enhanced MR lymphography, sentinel node and positron emission tomography imaging, and contrast-enhanced ultrasound.
Contrast Media↗
Glucose-receptor MR imaging of tumors: study in mice with PEGylated paramagnetic niosomes.
PURPOSE: To evaluate a magnetic resonance (MR) imaging contrast agent for tumor detection based on paramagnetic nonionic vesicles (niosomes) bearing polyethylene glycol (PEG) and glucose conjugates for the targeting of overexpressed glucose receptors. MATERIALS AND METHODS: Four gadobenate dimeglumine-loaded niosome preparations including nonconjugated niosomes, niosomes bearing glucose conjugates (N-palmitoyl glucosamine [NPG]), niosomes bearing PEG 4400, and niosomes bearing both PEG and NPG were tested. In vitro cellular uptake was measured at electron paramagnetic resonance (EPR) after incubation with human prostate carcinoma, PC3, cells. In vivo distribution was studied at MR imaging 6, 12, and 24 hours after injection, with assessment of tumor, brain, liver, and muscle signal intensity (SI) in 49 mice bearing PC3 cells. Efficiency of targeted contrast agents was assessed with tumor-to-muscle contrast-to-noise ratio (CNR). Testing for differences was performed with analysis of variance followed by a posteriori Fisher test. RESULTS: In vitro, gadolinium could be detected at EPR only in cell pellets incubated with niosomes bearing glucose conjugates or niosomes bearing both glucose conjugates and PEG (4.9. 10(-15) and 4.5. 10(-15) mol gadolinium per PC3 cell). In vivo, marked predominant tumor enhancement was demonstrated 24 hours after injection of glycosylated PEG niosomes (P <.01); no significant differences were observed following injection of nonconjugated niosomes, glycosylated niosomes, or PEG 4400 niosomes. Twenty-four hours after injection, sole presence of NPG or PEG 4400 on the surface of the niosome led to higher tumor-to-muscle CNR than that observed after injection of nonconjugated niosomes (CNR of 3.3 +/- 0.7 [SD], 3.4 +/- 2.2, and 0 +/- 1.9). Combination of NPG and PEG led to even higher tumor-to-muscle CNR (6.3 +/- 2.2). CONCLUSION: Combination of PEG and glucose conjugates on the surface of niosomes significantly improved tumor targeting of an encapsulated paramagnetic agent assessed with MR imaging in a human carcinoma xenograft model.
Animals↗
[Hepatocellular carcinoma without cirrhosis in a patient with nonalcoholic steatohepatitis].
All cases of hepatocellular carcinoma reported thus for in patients with nonalcoholic steatohepatitis have occurred on preexisting cirrhosis. We report the case of a 68-Year-old male patient with nonalcoholic steatohepatitis who developed hepatocellular carcinoma in the absence of cirrhosis. This observation suggests a possible relationship between nonalcoholic steatohepatitis and/or excess body weight, and hepatocellular carcinoma independent of cirrhosis. Further epidemiological studies are needed to evaluate the incidence of this association.
Aged↗
Comparison of in vitro and in vivo MRI of the spine using parallel imaging.
OBJECTIVE: The purpose of this study was to compare the image quality of two parallel-imaging methods applied to standard turbo spin-echo T2-weighted imaging of the lumbar spine. MATERIALS AND METHODS: Phantom imaging and lumbar spine studies of 15 healthy subjects were performed using T2-weighted turbo spin-echo sequences obtained with and without parallel imaging (generalized autocalibrating partially parallel acquisition [GRAPPA] and modified sensitive encoding [mSENSE]) on a 1.5-T magnet. The signal-to-noise ratio (SNR) and uniformity were measured in the phantom, and SNR and signal difference-noise ratio were evaluated in cerebrospinal fluid, vertebral bodies, and subcutaneous fat of the volunteers, using both techniques sequentially. Aliasing artifacts on GRAPPA and mSENSE images were visually evaluated. SNRs were compared using the Student's paired t test, with p values less than 0.05 considered significant. RESULTS: In the phantom study, when the same number of coil elements were used (n = 3), SNR and uniformity values obtained with standard T2-weighted turbo spin-echo sequences were higher than those obtained with parallel sequences. The GRAPPA SNR obtained with three coil elements was higher than the standard T2-weighted SNR obtained with one coil element. Similar findings were noted regarding uniformity. In the lumbar spine, GRAPPA SNR values for fat, cerebrospinal fluid, and vertebral bodies were significantly higher than mSENSE SNR values, with a p value less than 0.01, but were not significantly different from T2-weighted turbo spin-echo SNR values. GRAPPA signal difference-noise ratio values were significantly higher than mSENSE signal difference-noise ratio values, with a p value less than 0.01, but were not significantly different from T2-weighted turbo spin-echo signal difference-noise ratio values. GRAPPA produced fewer aliasing artifacts than mSENSE. CONCLUSION: In spine MRI, GRAPPA may be used to reduce scanning time and yields a higher SNR than mSENSE without any increase in aliasing artifacts and with an SNR similar to that obtained with standard T2-weighted turbo spin-echo.
Artifacts↗
Simultaneous bilateral breast and high-resolution axillary MRI of patients with breast cancer: preliminary results.
OBJECTIVE: The aims of this study were to develop a standardized one-step procedure for simultaneous high-resolution MRI of the axilla and bilateral breast MRI and to identify nodal features suggestive of metastatic involvement. SUBJECTS AND METHODS. We studied 16 women undergoing axillary lymph node dissection after combined bilateral breast MRI and high-resolution MRI of the axilla with a maximum in-plane resolution of 0.6 x 0.4 mm. MRI was performed using a standard double breast coil and a 15-cm round flexible surface coil adapted to the axilla. High-resolution axillary sequences, including inversion recovery T2- and spin-echo T1-weighted sequences, were performed before and after gadolinium chelates bolus injection. Axillary image analysis focused on nodal morphology including size, contour regularity, cortex and hilar appearance, signal intensity, and enhancement parameters. Axillary MRI findings were compared with the final pathogic results from axillary lymph node dissection in all patients. Patients were divided into groups according to the final pathologic axillary status. Differences in MRI lymph node features across the groups were tested using a t test for quantitative data and the chisquare test or Fisher's exact test for binary data. RESULTS: The features of the axilla on high-resolution MRI that best discriminated between patients with positive pathologic findings and those with negative pathologic findings were the presence of nodes with irregular contours (p < 10(-4)), high signal intensity on T2 sequences (p < 10(-3)), marked gadolinium enhancement (p < 10(-3)), and round hila and abnormal cortexes (p < 0.05). CONCLUSION: Breast tissue and axillary lymph nodes both can be analyzed on MRI in a one-step process using a bilateral breast coil combined with a surface coil. Morphologic features observed on high-resolution MRI of the axilla can improve the identification of metastatic nodes.
Adult↗
Internal abdominal herniations.
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Cecal Diseases↗
[Imaging in congenital fibrocystic diseases of the liver].
The identification of dilatations of the intrahepatic bile ducts in the absence of bile duct obstruction is rare. Imaging techniques, especially MR cholangio-pancreaticography, generally permit the distinction between fibrocystic liver diseases and polycystic liver diseases. The presence of dilated sacciform or tubular bile ducts on cholangio-pancreaticography associated with a centrally located fibrovascular bundle (central dot sign) suggests Caroli's syndrome. The presence of associated signs of liver dysmorphia including right lobe atrophy and hypertrophy of segment IV suggests associated congenital hepatic fibrosis. The findings on cholangio-pancreaticography, computerized tomography or Doppler ultrasonography correlate well with the pathogenesis of fibrocystic liver diseases, linked to an embryologic malformation of the ductal plate.
Biliary Tract↗