Mediastinal lymphoma: quantitative changes in gadolinium enhancement at MR imaging after treatment.

PURPOSE: To compare changes in gadolinium enhancement at magnetic resonance (MR) imaging with outcome in mediastinal lymphoma after treatment. MATERIALS AND METHODS: Thirty-one patients with bulky mediastinal lymphoma (17 with Hodgkin disease, 14 with non-Hodgkin lymphoma) underwent serial MR imaging before and up to 50 months after treatment, with routine follow-up (including computed tomography). Signal intensity ratios between masses and muscle were calculated on T1-weighted, T2-weighted, and contrast material-enhanced T1-weighted spin-echo MR images. The percentage enhancement and signal intensity ratios of mediastinal masses on T2-weighted MR images were calculated at diagnosis and during and after treatment. RESULTS: Twenty-one patients with persistent complete remission had a mean percentage enhancement of residual masses (4%; range, -26% to 40%) that was significantly lower than that of initial masses (78%; range, 41%-124%). Although the mean signal intensity ratio of residual masses on T2-weighted images was significantly lower than that of initial masses, an increase in this ratio was observed in four patients after treatment. In seven patients with relapse, the percentage enhancement value of the residual mass was as high as that of the initial mass. CONCLUSION: Gadolinium enhancement of lymphomatous masses of the mediastinum decreased markedly after treatment in patients in continuous complete remission but not in patients with relapse.

CT demonstration of the spontaneous regression of a hypervascular lesion in cirrhotic liver.

In patients with liver cirrhosis, arterial phase enhancement of nodular lesions on helical-CT is currently considered to be highly predictive of malignancy. We report the spontaneous regression of a hypervascular hepatic nodule in a patient with liver cirrhosis within 7 months demonstrated by helical-CT follow-up. This suggests that tumour angiogenesis known to be an obligatory step for acquisition of malignant properties could regress, and can be demonstrated by helical CT. Radiologists should be aware that CT detection of a hypervascular nodule in a cirrhotic liver is not always predictive of a malignant outcome.

Acute swelling of the limbs: magnetic resonance pictorial review of fascial and muscle signal changes.

OBJECTIVE: This pictorial review analyzes the magnetic resonance (MR) fascial/muscular changes in 69 patients referred as emergencies with acute swelling of the limbs (ASL) from various causes. METHODS AND MATERIAL: A prospective MR imaging (MRI) study of 69 patients referred as emergencies for ASL was performed. Our population consisted of 45 patients with skin and soft-tissue infections (cellulitis and necrotizing fasciitis, and pyomyositis), six patients with soft-tissue inflammatory diseases (dermatomyositis, graft-versus-host disease), 11 patients with acute deep venous thrombosis, three patients with rhabdomyolysis, one patient with acute denervation and three other patients with rare diseases. Hematomas, tumorous or infectious bone involvement and soft-tissue tumors were excluded. All studies included spin echo T1-weighted images and spin echo T2-weighted images. Gadolinium-enhanced spin echo T1-weighted images were obtained when an abscess was suspected on T2-weighted images. Selective fat-saturated T1- and T2-weighted sequences were also used. MRI analysis was performed to obtain a compartmentalized anatomical approach according to the location of signal abnormalities in subcutaneous fat, superficial and deep fascia and muscle. RESULTS: In all patients with ASL, MRI demonstrated soft-tissue abnormalities involving subcutaneous fat, superficial fascia, deep fascia, or muscle. Although MR findings were non-specific, MRI appears sensitive for detecting subtle fascial and muscle signal changes. CONCLUSIONS: In skin and soft-tissue infections, MRI can be helpful for therapeutic management by determining the depth of soft-tissue involvement, particularly within fasciae and muscles, which is partly related to the severity of cellulitis with severe systemic manifestations. MRI can also aid the surgeon in diagnosing abscesses. In inflammatory diseases, MRI can determine the best site for biopsy and also monitor therapeutic response.

[Role of magnetic resonance imaging in liver pathology]. / Place de l'imagerie par résonance magnétique en pathologie hépatique.

The increasingly common use of ultrasound examination of the liver has led to increased detection of hepatic tumours, showing a hitherto unsuspected prevalence. Improved techniques in MRI, such as dynamic sequences and new contrast media, are ameliorating the detection and characterization of the lesions, in particular with regard to computed tomography. In addition, since MRI is more sensitive to different components than in computed tomography, it permits better study of diffuse diseases such as haemochromatosis or fatty infiltration, particularly in pseudotumoural forms. The continuing progress in system improvement makes MRI an excellent method for diagnosis of bile duct disorders, especially in case of obstruction.

Prevention of thrombotic complications of the nephrotic syndrome by the low-molecular-weight heparin enoxaparin.

The nephrotic syndrome (NS) carries one of the highest risks of thrombotic complications. Consequently, over the last 15 years, some nephrologists have treated patients risk (i.e. those with albuminemia < 20 g/l and membranous nephropathy) with anticoagulants: either subcutaneous heparin (Kakkar protocol) or antivitamin K. Low-molecular-weight heparin (LMWH) has a longer plasma half-life and better bioavailability than standard heparin and can thus be administered as a single daily injection. LMWH also carries a lower risk of hemorrhage. We prospectively studied the safety and efficacy of the LMWH Enoxaparin for preventive anticoagulation in NS. In a preliminary study, 10 adult nephrotic patients with biological markers of thrombosis risk (severe hypoalbuminemia and/or anomalies of the fibrinolytic pathway and/or deficiency in coagulation inhibitors) were given 40 mg (4,000 U) of Enoxaparin daily for at least 3 months; 3 patients were treated for 3 months, 1 for 6 months and 6 for 12 months. Patients were assessed for silent thrombosis, using renal vein Doppler ultrasonography, lower leg vein Doppler ultrasonography and lung ventilation-perfusion scintigraphy, before entry to the trial and subsequently at 3-month intervals. As LWMH caused no obvious side effects and no thrombosis was observed during the pilot study, we then placed 55 adult nephrotic patients free of thrombosis on the same treatment. Patients were seen according to the usual calendar required by their individual illnesses. At each examination, patients were assessed for clinical signs and symptoms of thrombosis and side effects; plasma D-dimer and urinary fibrin-fibrinogen degradation products were also measured at each visit.(ABSTRACT TRUNCATED AT 250 WORDS)

MR imaging in acute infectious cellulitis.

PURPOSE: To describe magnetic resonance (MR) imaging findings in acute infectious cellulitis and assess its value for the diagnosis of severe necrotizing forms. MATERIALS AND METHODS: Spin-echo (SE) T1- and T2-weighted imaging was performed in 36 patients with acute infectious cellulitis. T1-weighted SE images obtained after injection of a paramagnetic contrast agent were also obtained when an abscess was suspected on precontrast images. Sixteen patients underwent surgical débridement, along with fascial and muscle biopsy. RESULTS: Distinct MR imaging features were found in patients with necrotizing soft-tissue infections, that is, hyperintense signal on T2-weighted images at the deep fasciae, poorly defined areas of hyperintense signal on T2-weighted images within muscles, and peripheral enhancement on contrast material-enhanced T1-weighted images. In nonnecrotizing cellulitis, signal intensity abnormalities were seen only in the subcutaneous fat. CONCLUSION: The precise extent of acute cellulitis and the presence of necrotizing soft-tissue infections can be determined with MR imaging, particularly on T2-weighted images.

Sclerosed liver hemangioma mimicking malignant tumor at MR imaging: pathologic correlation.

This case report illustrates atypical magnetic resonance (MR) imaging findings in a liver hemangioma mimicking a malignant lesion--lower signal intensity than cerebrospinal fluid on T2-weighted spin-echo images and lack of early enhancement on dynamic contrast material--enhanced gradient-echo images. Pathologic analysis demonstrated nearly total replacement of the vascular cavities by dense fibrous tissue. In this rare, sclerosed form, this lesion could not be defined as a hemangioma with MR imaging.

[Massive rectal hemorrhage related to an isolated diverticulum of the right colon in an young patient]. / Rectorragie massive en rapport avec un diverticule isolé du côlon droit chez un sujet jeune.

We report a case of a 32-year-old man admitted for massive rectal bleeding related to a solitary diverticulum of the right colon. A superior mesenteric angiogram performed in emergency indicated the site of bleeding, but the correct diagnosis was only established at the histologic examination of the right colon that was surgically resected.

Detection of multiple myeloma involving the spine: efficacy of fat-suppression and contrast-enhanced MR imaging.

OBJECTIVE: To determine the efficacy of fat-suppressed sequences and contrast-enhanced MR imaging for the detection of focal spinal lesions caused by multiple myeloma, we obtained MR images in 32 patients with newly diagnosed myeloma who had back pain. SUBJECTS AND METHODS: All patients had biopsy-proved myeloma and had MR imaging at the painful level of the spine. Spin-echo T1-weighted, T2-weighted, and short TI inversion-recovery (STIR) images; dynamic ultrafast low-angle shot (turbo-FLASH) images after IV injection of a bolus of paramagnetic contrast material; and contrast-enhanced T1-weighted images were obtained. We qualitatively compared the signal intensities and contrast enhancement of focal lesions with those of the surrounding vertebral bodies. RESULTS: Multiple lesions were detected in all but two of the 32 patients. On T2-weighted and STIR images, all lesions had homogeneously high signal intensity. On T1-weighted images, the lesions were visible as hypointense areas compared with surrounding bone in all except four patients, in whom the lesions were isointense or hyperintense. All tumor nodules enhanced on turbo-FLASH images obtained in the arterial phase. No additional lesions were seen on STIR or contrast-enhanced images. MR findings resulted in a change in the staging of the disease in one patient and led to prompt treatment in five patients with epidural involvement. CONCLUSION: MR imaging appears to be helpful in detecting spinal involvement in patients with multiple myeloma. The diagnosis of spinal lesions is best achieved by using either fat-suppressed or T2-weighted images. Although myeloma lesions enhanced in all patients, contrast material appears to be of no value for the detection of additional lesions.