Evolving radiological features of hypothalamo-pituitary lesions in adult patients with Langerhans cell histiocytosis (LCH).

Langerhans cell histiocytosis (LCH) is a rare, systemic disease caused by monoclonal expansion of dendritic cells that shows a particular predilection for the hypothalamic-pituitary system (HPS). We studied the function (anterior and posterior pituitary hormonal secretion) and morphology using magnetic resonance imaging (MRI) of the HPS in 17 adult patients (seven males, median age 35 years, range 18-59 years) with multisystem LCH. We also evaluated the evolution of structural HPS abnormalities in relation to pituitary function and response to treatment in 12 of these patients during a median follow-up period of 3.75 years (range 1.5-10 years). Of the 17 patients, 14 (82%) had abnormal HPS imaging, and 12 (70%) had more than one area involved. Lack of the bright spot of the posterior pituitary lobe was typically found in all patients with the diagnosis of diabetes insipidus (DI). Eight patients (47%) had infundibular enlargement, six (35%) pituitary infiltration, four (24%) partially or completely empty sella, three (18%) hypothalamic involvement, and two (12%) infundibular atrophy. DI was found in 16 patients (94%) and anterior pituitary hormonal deficiency (APHD) in 10 patients (59%); two patients had single (12%) and 8 (47%) multiple APHD. During the follow-up period there was improvement of the initially demonstrated HPS pathology in seven (47%) patients, and five (33%) of them had received at least one form of treatment. APHD and DI persisted in all patients except in one in whom established gonadotrophin deficiency recovered. In summary, DI and APHD are very common in patients with multisystem LCH and are almost always associated with abnormal HPS imaging.

MR urography in the diagnosis of urinary tract obstruction.

OBJECTIVE: To evaluate the efficiency of MR urography in depicting the urinary tract. METHODS: 33 patients with urinary tract abnormalities were additionally evaluated with MR urography. 25 had dilated upper urinary tracts because of urinary obstruction and 8 had normal tracts. MR urography was performed with a 1,5T magnet using a heavy T2w sequence (3D-IR-TSE) in the coronal plane. Images were post-processed using the MIP algorithm. Both reconstructed and source images were evaluated. The results of MR urography were compared with the final diagnosis, which was established surgically in 23 cases, and with multimodality imaging workup in 10 cases. RESULTS: MR urography correctly depicted the level of obstruction and the degree of dilatation of the urinary tract in all 25 patients with hydronephrotic kidneys (sensitivity 100%). Additionally, it succeeded in suggesting the underlying pathology in 25 cases (48%). Concerning the 8 patients without dilatation of the urinary tract, there was either no depiction or depiction was bad. CONCLUSION: MR urography, a new noninvasive technique, demonstrates 100% sensitivity in diagnosing urinary tract obstruction and also suggests the underlying pathology in many cases. In nondilated systems it is not possible to get good images because MR urography only depicts fluid in the urinary tract. Thus we believe that MR urography can provide a reliable alternative in selected cases as opposed to other more invasive modalities, such as retrograde or antegrade urography, and is without the risk of contrast media and radiation exposure.