Clinical relevance of diffusion and perfusion magnetic resonance imaging in assessing intra-axial brain tumors.

Advanced magnetic resonance (MR) imaging techniques provide physiologic information that complements the anatomic information available from conventional MR imaging. We evaluated the roles of diffusion and perfusion imaging for the assessment of grade and type of histologically proven intraaxial brain tumors. A total of 28 patients with intraaxial brain tumors underwent conventional MR imaging (T2- and T1-weighted sequences after gadobenate dimeglumine injection), diffusion imaging and T2*-weighted echo-planar perfusion imaging. Examinations were performed on 19 patients during initial diagnosis and on nine patients during follow-up therapy. Determinations of relative cerebral blood volume (rCBV) and apparent diffusion coefficient (ADC) were performed in the solid parts of each tumor, peritumoral region and contralateral white matter. For gliomas, rCBV values were greater in high-grade than in low-grade tumors (3.87+/-1.94 versus 1.30+/-0.42) at the time of initial diagnosis. rCBV values were increased in all recurrent tumors, except in one patient who presented with a combination of recurrent glioblastoma and massive radionecrosis on histology. Low-grade gliomas had low rCBV even in the presence of contrast medium enhancement. Differentiation between high- and low-grade gliomas was not possible using diffusion-weighted images and ADC values alone. In the peritumoral areas of untreated high-grade gliomas and metastases, the mean rCBV values were higher for high-grade gliomas (1.7+/-0.37) than for metastases (0.54+/-0.18) while the mean ADC values were higher for metastases. The rCBV values of four lymphomas were low and the signal intensity-time curves revealed a significant increase in signal intensity after the first pass of gadobenate dimeglumine. Diffusion and perfusion imaging, even with relatively short imaging and data processing times, provide important information for lesion characterization.

Acute hypertensive encephalopathy with widespread small-vessel disease at MRI in a diabetic patient: pathogenetic hypotheses.

We report unusual magnetic resonance imaging (MRI) findings in a diabetic patient with neglected hypertension and hyperglycemia, presenting with seizures and coma. Outcome was fatal despite intensive care. The MRI findings included bilateral insular and temporo-occipital grey and white matter involvement, and numerous, scattered, lacunar-like lesions involving the peripheral and deep white matter, basal ganglia grey matter, and brainstem. Lesions had a low apparent diffusion coefficient, and some enhanced following contrast injection. Hypertensive encephalopathy with widespread and severe acute small-vessel disease was considered. Pathophysiology is discussed.

[Correlation between cranial vault size and brain size over time: preliminary MRI evaluation]. / Evolution comparative de la voûte crânienne et du parenchyme cérébral avec l'âge: étude préliminaire en IRM.

OBJECTIVES: To correlate changes of cranial vault measurements of an adult population during the aging process with brain size using the maximum width of the third ventricle in the axial AC-PC plane. MATERIALS AND METHODS: Prospective study of 126 adult subjects (range: 20 to 80 years) with normal brain MRI and without history of neuropsychiatric disorder. MEASUREMENTS INCLUDED: Cranial vault (Maximum length: Glabella-Opisthocranion, Maximum width: euryon-euryon, and maximum height: Basion-Vertex) measurements and maximum width of the third ventricle in the A C-PC plane. RESULTS: Vault measurements (length, width, high) were similar for every age group, irrespective of gender. The variability of cranial vault measurements between individuals was low (<1 cm). Cranial vault measurements were larger for men, but this was not significant when adjusted for body height Comparatively, a gradual widening of the third ventricle, with an exponential behavior, was observed with advancing age. CONCLUSION: Our results indicate that cranial vault measurements are stable over time (between 20-80 years) comparatively to brain atrophy with advancing age. The low variability of cranial vault measurements and their stability over time should be taken into account during segmentation and normalization of brain parenchymal structures.

Diffusion-weighted magnetic resonance imaging in Marchiafava-Bignami disease: follow-up studies.

Marchiafava-Bignami disease (MBD), an acute toxic demyelination of the corpus callosum in alcoholics, is associated with poor evolution in the majority of patients. We report here the early and late diffusion magnetic resonance imaging (MRI) and apparent diffusion coefficient (ADC) studies of two patients suffering from MBD with favourable outcome. Diffusion and anatomical MRI changes were parallel to the clinical evolution, suggesting that MRI studies can be helpful for diagnosis and follow-up. Unlike in stroke, restricted diffusion on ADC maps does not seem to be a sign of irreversibility.

[MRI of central nervous system in a series of 58 systemic lupus erythematosus (SLE) patients with or without overt neuropsychiatric manifestations]. / Apport de l'IRM cérébrale dans une série de 58 cas de malade lupique avec ou sans manifestations neuropsychiatriques.

PURPOSE: Central nervous (CNS) involvement in SLE is common and can be evaluated with MRI. The primary goal of this study was to evaluate with high-field MRI the CNS involvement in a series of SLE patients with or without neuropsychiatric symptoms. The secondary goal was to detect a possible relationship between MRI and clinical or biological parameters in SLE. MATERIALS AND METHODS: We correlated the clinical and biological parameters of 58 patients with a lupus defined according to the American College of Rheumatology criteria, including 30 with neuropsychiatric manifestations with conventional and modern MRI (including diffusion weighted-images, high-resolution 3D T1 weighted-images). The population studied was compared to a group of 18 normal controls. RESULTS: In 69% of cases, MRI demonstrated involvement of the CNS both in asymptomatic patients (64.3%) and in patients with neuropsychiatric manifestations (73.3%): microembolic signals, cerebral infarctions (associated with the anti-phospholipid syndrome), atrophy, basal ganglia involvement, posterior leucoencephalopathy, subcortical calcification or hemosiderin deposits (T2*), dilated perivascular spaces. CONCLUSION: MRI with adapted sequences clearly demonstrated the cerebral involvement in approximately 70% of SLE patients with or without neuropsychiatric symptoms.

Patellar instability: assessment on MR images by measuring the lateral trochlear inclination-initial experience.

Lateral trochlear inclination (LTI) of the knee was compared on magnetic resonance (MR) images obtained in 30 patients with patellar instability (PI) and 30 patients with nonspecific internal knee derangement. Differences in LTI values between the two populations were significant (P <.001). Reproducibility of the measurement was judged excellent with an intraclass correlation superior to 0.98. Below a threshold value fixed at 11 degrees, LTI appears to be an excellent diagnostic test of PI with a sensitivity of 0.93 (28/30), a specificity of 0.87 (26/30), and an accuracy of 0.90 (54/60).

Three-dimensional phase contrast MR cerebral venography with zero filling interpolation in the slice encoding direction.

The purpose of this study was to evaluate the magnetic resonance (MR) cerebral venography findings of a three-dimensional phase contrast MR sequence with zero filling interpolation of the data in the slice encoding direction. Fifty volunteers were enrolled in the study. Images were obtained on a 1.5 MR imaging system with acquisition time of 12 min. MIP images were reconstructed throughout the entire imaging volume. A grading scale system was used to assess dural venous sinuses, major deep veins, cortical, and cortical eponymic veins. Inferior group of dural venous sinuses, inferior sagittal sinus, and cortical eponymic veins were poorly demonstrated. Score of the superior sagittal sinus, the straight sinus, the confluence of the superior sinus group, the right transverse and sigmoid sinuses, the internal veins, and the vein of Galen was excellent. The score of the left transverse and sigmoid sinuses was good. In conclusion, when using zero filling interpolation of the data in a three-dimensional phase contrast MR cerebral venography sequence, the superior group of dural venous sinuses and main major deep veins are demonstrated with good conspicuity.

Magnetic resonance imaging findings in idiopathic adhesive capsulitis of the shoulder.

OBJECTIVES: To describe magnetic resonance imaging findings in idiopathic adhesive capsulitis of the shoulder. PATIENTS AND METHODS: Twenty patients with idiopathic adhesive capsulitis of the shoulder underwent magnetic resonance imaging involving two spin-echo T2-weighted sequences with fat saturation and two spin-echo T1-weighted postgadolinium sequences; for all sequences, sections were obtained in the oblique coronal and transverse axial planes. Findings were compared to those obtained using the same imaging protocol in 15 patients with clinical manifestations of rotator cuff tear. RESULTS: Postgadolinium enhancement of the joint capsule and synovial membrane was seen in the rotator interval in all 25 adhesive capsulitis patients and in the axillary recess in 22 of the 25. Only one of the 15 rotator cuff tear patients had this finding. In both groups, postgadolinium enhancement occurred in the subacromial bursa, in the rotator cuff tendons, and in the acromioclavicular joint. No significant rotator cuff tears were found in any of the adhesive capsulitis patients. CONCLUSION: In difficult cases, magnetic resonance imaging with gadolinium injection can contribute to the diagnosis of idiopathic adhesive capsulitis of the shoulder.

Comparative assessment of digital and analog radiography: diagnostic accuracy, cost analysis and quality of care.

OBJECTIVE: The aim of this study was to compare digital and conventional radiography for diagnostic accuracy, direct costs, and quality of care. MATERIALS AND METHODS: Diagnostic accuracy was assessed by a critical review of the literature on sensitivity, specificity and ROC analysis of these imaging techniques and by a survey with a panel of radiologists. Direct costs and quality of care were evaluated with a before/after study of the implementation of digital radiography in a Department of Radiology in 'Hospices Civils de Lyon' (France). We included 292 patients and measured duration of examinations and direct costs of equipment, films, maintenance and depreciation. To evaluate any changes in working conditions and patient management, a questionnaire was filled out by the staff of the department. RESULTS: Diagnostic accuracy with digital radiography was equivalent to that of conventional radiography but there were wide variations depending on the type of examination. In 1993, although digital radiography resulted in savings of FF 18,000 including tax (US$ 3600) on film consumption for 1 year of examinations, there was a global additional cost of FF 253,000 (US$ 50,600) for maintenance and depreciation. Results showed a nonsignificant tendency to reduced procedure times for all examinations. Working conditions improved, including greater availability for the patient, improved safety, and increased job interest. CONCLUSION: Digital radiography can be introduced into a large hospital to improve patient and staff conditions, at a higher cost than analog radiography, and depending on the type of examinations performed by the radiology department.

Transplanted renal artery: detection of stenosis with color Doppler US.

PURPOSE: To evaluate the influence of various parameters on peak systolic velocity in the transplanted renal artery and to define the normal range of peak systolic velocity. MATERIAL AND METHODS: Color Doppler ultrasonographic (US) findings in 105 patients were reviewed. There were no clinical or biologic findings suggestive of a stenosis in the transplanted renal artery in these patients. The peak systolic velocity in the transplanted renal and external iliac arteries and the renal resistive index were measured. RESULTS: A large range of peak systolic velocities was noted in the transplanted renal artery. Peak systolic velocity in the renal artery was statistically significantly correlated with that in the external iliac artery when there was no pronounced vessel curvature. There was no relationship between peak systolic velocity and resistive index or time between transplantation and US. High peak systolic velocity was associated with a pronounced vessel curvature. CONCLUSION: The normal range of peak systolic velocity in the transplanted renal artery has considerable variability. Because of the strong correlation, the ratio of velocity in the renal artery to that in the external iliac artery may be useful in detection of stenosis.

Bilateral emphysematous pyelonephritis resolving to medical therapy: demonstration by US and CT.

Emphysematous pyelonephritis (EPN) is an uncommon and life-threatening necrotizing infection of the renal parenchyma occurring mostly in diabetic patients. It is usually unilateral. Nephrectomy is the current therapeutic procedure. We report the plain radiograph, US and CT findings in a 26-year-old diabetic woman who presented with bilateral EPN and was cured by medical treatment alone.

Transplant renal artery stenosis. Evaluation of diagnosis with magnetic resonance angiography compared with color duplex sonography and arteriography.

The goal of this study was to assess the value of a three-dimensional phase contrast magnetic resonance angiography (3D PC MRA) for diagnosing transplant renal artery stenosis (TRAS). Twelve consecutive patients clinically suspected of having TRAS were prospectively enrolled during a period of 18 months. Delays from transplantation varied from 3 months to 4 years (mean: 18.3 months). Patients first had color Doppler sonography, then MRA-and, on the following day, intraarterial digital subtraction angiography (IADSA). The site of the maximum peak systolic velocity was noted when doing the report of each color Doppler sonogram. On MRA images, any signal cutoff or any vascular narrowing of more than 50% of the diameter of the vessel was considered to be a significant stenosis. Eight patients were considered to have TRAS on MRA, but only two stenoses were noted on IADSA. The six false-positive results of MRA (due to major intravoxel phase dispersion) were observed when elevated peak systolic velocities were noted on doppler sonograms (mean: 214 cm/sec). These elevated peak systolic velocities were noted in the proximal part of the renal artery when there was a tortuous vessel or a sharp angle between the renal artery and the parent vessel. It is our opinion that 3D PC MRA is of limited value for the diagnosis of renal transplant artery stenosis because of a high number of false-positive results.

[Postpartum mesenteric-portal thrombosis of pseudotumor presentation]. / Thrombose mésentérico-portale du post-partum à présentation pseudotumorale.

Portal thrombosis complicating delivery has not been reported to date. We report on a 28-year-old woman who presented 15 days after abdominal delivery with an abdominal mass. US, color Doppler and CT showed thrombosis of the superior mesenteric and portal veins. Percutaneous thrombolysis was unsuccessful. US and Doppler follow-up showed progressive portal hypertension with recanalization of the left portal vein.

Late MR follow-up of hypothalamic hamartomas.

The absence of changes over time in the diagnostic features of suspected hypothalamic hamartomas is of paramount importance. Since magnetic resonance (MR) imaging is very sensitive to modifications in the brain parenchyma, a late MR follow-up study was performed in five children. In all cases, the diagnosis of hypothalamic hamartoma has been suspected on the basis of the association of central precocious puberty and the presence of a mass in the inferior aspect of the hypothalamus, demonstrated on previous MR studies. Late MR evaluation (after a mean of 39 months) demonstrated stability of the lesions in shape, size, and signal intensity. In three cases the lesions demonstrated a rim of isointense signal with a hyperintense center on T2-weighted sequences. In two cases a Chiari I malformation was found in association with the hypothalamic malformation. In one case a pineal cyst was demonstrated. These unusual findings are discussed. Late MR follow-up showed the absence of changes in the lesions over time, allowing the diagnosis to be confirmed.

Sclerosing hemangioma of the lung: radiological findings and pathological diagnosis.

We present a case of sclerosing hemangioma of the lung, revealed as a solitary round mass on routine chest radiography in a 14-year-old patient. CT and MRI findings were consistent with a solid neoplasm but no specific characteristics were identified. Analysis of the surgical biopsy material led to a cytological diagnosis of adenocarcinoma. Definitive diagnosis of sclerosing hemangioma of the lung was established on pathological examination of the whole surgical specimen.