Catherine Roy

Superselective Endo-Vascular Treatment of Renal Vascular Lesions

Embolization with platinum micro-coils delivered through the Tracker-18 micro-catheter was performed in 6 patients when peripheral selective catheterization with standard angiographic catheters was not possible. The patients had a total of 7 peripheral renal vascular lesions (3 arteriovenous fistulas, 2 false aneurysms, 1 direct vascular trauma and 1 arteriovenous malformation). In all patients we initially used platinum micro-coils as the embolic agent. Two patients required repeat embolization with glue. Endo-vascular treatment was technically successful in all cases and no complications were encountered. There was no renal parenchyma infarction in 3 patients and small peripheral infarctions (10 to 15% of the renal parenchyma) occurred in 3. Super selective endo-vascular treatment with a variable stiffness catheter is safe and useful technique when classical methods of embolization are not possible.

Assessment of painful ureterohydronephrosis during pregnancy by MR urography

The purpose of this study was to assess the value of the fast imaging sequence called RARE (rapid acquisition with relaxation enhancement) MR urography (or RMU) In pregnant women with painful ureterohydronephrosis. A total of 17 pregnant women with an acute flank pain were examined with RMU. Results were compared with those of US, X-rays and the evolution of symptoms. The gold standard techniques used to evaluate the results of MR urography were US when it showed the entire dilated urinary tract and the nature of the obstruction (9 cases), limited intravenous urography (IVU) when performed (3 cases) or endoscopic procedure (5 cases). The accuracy of RMU in the detection of urinary tract dilatation and the localization of the level of obstruction was excellent (sensitivity 100% in our series). The determination of the type of obstruction, intrinsic vs extrinsic, was always exact. The RMU technique alone could not specify the exact nature of the obstruction. The RMU technique is able to differentiate a physiological from a pathological ureterohydronephrosis during pregnancy. It could be considered as the procedure of choice when US failed to establish the differential diagnosis.

Natural History of Residual Renal Stone Fragments after ESWL

Objective: After extracorporeal shock wave lithotripsy (ESWL), residual fragments (RF) 4 mm or less are usually considered as clinically insignificant. We retrospectively reviewed the natural history and clinical significance of 97 noninfected and isolated RF (4 mm or less) observed 3 months after the last ESWL session on renal tomography.Patients and Methods: They represented 83 among 1,216 patients treated by ESWL over a 9–year period (1989–1997). These RF were mostly localized in the inferior calyx (62%). Median follow–up was 40.6 months (range: 7–96 months). Renal tomography was always performed at the end of follow–up.Results: Stone–free status, or a decreased, stable or increased amount of residual stone occurred in 27 (33%), 1 (1%), 24 (29%) and 31 (37%) of the 83 patients, respectively. During this study, 18 patients (22%) were proposed for a complementary treatment related to a size increase of the residual fragments (13 ESWL, 1 retrograde endoscopy, 3 percutaneous nephrolithotomy, and 1 polar inferior nephrectomy).Conclusion: The term clinically insignificant should not be employed to describe RF after ESWL. Efforts should be performed to obtain true stone–free status after ESWL.

Evaluation of RARE-MR urography in the assessment of ureterohydronephrosis

Objective The goal of this prospective study was to evaluate the value of the fast imaging sequence called RARE-MR urography (RMU) for the diagnosis of ureterohydronephrosis. Materials and Methods Sixty-nine patients underwent this procedure. The results were compared with those obtained by intravenous urography (IVU) and ultrasonography (US). Results The accuracy of RMU in the detection of urinary tract dilatation and the localization of the level of obstruction was excellent (100%). The determination of the type of obstruction, intrinsic versus extrinsic, was 80% by IVU and 60% for RMU. The RMU sequence alone could not specify the nature of the obstruction. Functional information about the obstructed collecting system could not be obtained. Conclusion The RMU technique may be considered in the following circumstances: contraindications to IVU (allergy to contrast medium, severe renal failure), impairment of renal excretion, and failure to locate the level of obstruction by US. The absence of ionizing radiations favors the promotion of this procedure to study ureterohydronephrosis during pregnancy.

MR urography in the evaluation of urinary tract obstruction

For a long time, conventional intravenous urography (IVU) has been considered the gold standard for the evaluation of the urinary tract. Over the years, the use of IVU has become somewhat less common as a result of the advent of cross-sectional imaging techniques, but it has remained in general use because of its low cost, availability, and ready acceptance by urologic surgeons. IVU has the disadvantage of requiring iodinated contrast media, which has a small risk and is undesirable in patients with previous reactions. IVU is of little use in patients with renal failure. The use of ionizing radiation may also be an issue, particularly in children, young adults, and obviously during pregnancy. Moreover, the clinical situation for most entities often dictate further imaging. Both ultrasound (US) and computed tomography (CT) have been advocated for evaluating urinary tract obstruction and other abnormalities. The concept of MR urography (MRU) is not new. In the past 10 years, this technique has been performed as a complementary tool to evaluate urinary tract abnormalities [1, 7]. The purpose of this paper is to discuss the technical aspect and the results of MRU and to give its potential applications.

Comparative Sensitivities of Functional MRI Sequences in Detection of Local Recurrence of Prostate Carcinoma After Radical Prostatectomy or External-Beam Radiotherapy

OBJECTIVE The aim of this retrospective study was to determine the respective accuracies of three types of functional MRI sequences-diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE) MRI, and 3D (1)H-MR spectroscopy (MRS)-in the depiction of local prostate cancer recurrence after two different initial therapy options. MATERIALS AND METHODS From a cohort of 83 patients with suspicion of local recurrence based on prostate-specific antigen (PSA) kinetics who were imaged on a 3-T MRI unit using an identical protocol including the three functional sequences with an endorectal coil, we selected 60 patients (group A, 28 patients who underwent radical prostatectomy; group B, 32 patients who underwent external-beam radiation) who had local recurrence ascertained on the basis of a transrectal ultrasound-guided biopsy results and a reduction in PSA level after salvage therapy. RESULTS All patients presented with a local relapse. Sensitivity with T2-weighted MRI and 3D (1)H-MRS sequences was 57% and 53%, respectively, for group A and 71% and 78%, respectively, for group B. DCE-MRI alone showed a sensitivity of 100% and 96%, respectively, for groups A and B. DWI alone had a higher sensitivity for group B (96%) than for group A (71%). The combination of T2-weighted imaging plus DWI plus DCE-MRI provided a sensitivity as high as 100% in group B. CONCLUSION The performance of functional imaging sequences for detecting recurrence is different after radical prostatectomy and external-beam radiotherapy. DCE-MRI is a valid and efficient tool to detect prostate cancer recurrence in radical prostatectomy as well as in external-beam radiotherapy. The combination of DCE-MRI and DWI is highly efficient after radiation therapy. Three-dimensional (1)H-MRS needs to be improved. Even though it is not accurate enough, T2-weighted imaging remains essential for the morphologic analysis of the area.

Fast imaging MR assessment of ureterohydronephrosis during pregnancy

PURPOSE to assess the value of the fast imaging sequence called RARE-MR-Urography (RMU) for the diagnosis of pathologic ureterohydronephrosis during pregnancy. MATERIALS AND METHODS 15 pregnant women with an acute flank pain were examined with RMU. Results were compared with those of ultrasonography (US), X-rays, and the evolution of symptoms. RESULTS the accuracy of RMU in the detection of urinary tract dilatation and the localization of the level of obstruction was excellent (100%). The determination of the type of obstruction, intrinsic vs. extrinsic, was always exact. RMU alone cannot specify the exact nature of the intrinsic obstruction. Ultrasonography gave less sensitive information in terms of level (60%) and type of obstruction (53%). CONCLUSION RMU is able to differentiate a physiological from a pathologic ureterohydronephrosis during pregnancy. It could be considered as a procedure of choice for special cases when US failed to establish this differential diagnosis.

Small Pelvic Lymph Node Metastases: Evaluation With MR Imaging

The purpose of this study was to determine if lymph node asymmetry in small (< 1.0 cm) pelvic lymph nodes was a significant prognostic feature in determining metastatic disease. Two hundred and sixteen patients who presented with pelvic carcinoma underwent magnetic resonance imaging (MRI). They were correlated with pathological findings obtained at surgery. We considered the maximum diameter (MAD) of both round- or oval-shaped suspicious masses seen in the axial plane. Two different cut-off values were determined: lymph node diameter greater than 1.0 cm (criterion 1) and lymph node diameter greater than 0.5 cm with asymmetry relative to the opposite side for lymph nodes ranging from 0.5 cm to 1.0 cm (criterion 2). With criterion 1, MRI had an accuracy of 88%, a sensitivity of 65%, a specificity of 96%, a positive predictive value (PPV) of 88% and a negative predictive value (NPV) of 88% in the detection of pelvic lymph node metastasis. By considering criterion 2, MRI had an accuracy of 85%, a sensitivity of 75%, a specificity of 91%, a PPV of 71% and a NPV of 91%. Normal small asymmetric lymph nodes were present in 5.6% of cases. Normal asymmetry of pelvic lymph nodes is not uncommon. It cannot be relied on to diagnose metastatic involvement in cases of small suspicious lymph nodes.

Myocardial Tagging with MR Imaging: Overview of Normal and Pathologic Findings

Magnetic resonance tagging is used to evaluate the dynamic deformation of lines or grids superimposed on the myocardium during the cardiac cycle. From these data, a specific postprocessing procedure provides two kinds of metrics: (a) three orthogonal components of myocardial motion (longitudinal, circumferential, and radial), and (b) rotation and torsion. Strain expresses the local myocardial deformation and is prone to important physiologic heterogeneities. Peak systolic strain is in the range of -15% to -20% for the longitudinal and circumferential components (fiber shortening) and 30%-40% for the radial component (wall thickening). The helical arrangement of myofibers that run in opposite directions at the epicardium and endocardium explains systolic twist (~15°). This torsion may be enhanced during the early stage of several diseases (eg, hypertrophic cardiomyopathy) or in heart failure with a normal left ventricular ejection fraction. Strain is generally impaired in ischemic heart disease and cardiomyopathy, but the most diagnostically significant finding is the early identification of contractile dysfunction on the basis of longitudinal and circumferential strain reduction in patients with apparently preserved systolic function. Thus, strain impairment appears to be a sensitive and promising marker of subclinical disease, with the potential for improving patient management.

Acute torsion of uterine leiomyoma: CT features

Acute torsion of a subserosal leiomyoma is a rare acute condition that is infrequently diagnosed preoperatively. It is a recognized surgical emergency, especially when additional systemic symptoms are associated. There are two main differential diagnoses: ovary/adnexal torsion and massive infarct inside a common leiomyoma. The diagnosis can be established by computed tomographic features. Ultrasound examination is less sensitive.