Hypothalamic-pituitary dwarfism: Comparison between MR imaging and CT findings

Abstract

Magnetic Resonance (MR) imaging was carried out on 33 patients with idiopathic growth hormone deficiency, in 22 of whom CT scan had been carried-out previously. Twenty-one patients presented some complications at birth. Both MR and CT were positive in the evaluation of the sella. MR imaging exhibited a higher degree of accuracy than CT in the evaluation of pituitary gland, pituitary stalk and brain anomalies. On the basis of pituitary morphology demonstrated by MR imaging, and perinatal histories, a classification is proposed which divides our patients into three group: A) a first group of 13 patients presenting severe hypoplasia of the anterior pituitary lobe, hypoplasia of the stalk and ectopia of posterior lobe. The underlying cause of these anatomic defects might be developmental in origin, and date from early intrauterine life, probably worsened at birth. B) a second group of 10 patients presenting severe hypoplasia of the anterior pituitary lobe. A perinatal event and birth trauma might be responsible for pituitary damage. C) a third group of 10 patients with no morphological abnormalities of the pituitary gland. A derangement of the neuroendocrine mechanism which control the growth hormone secretion might account for these patients.

Investigação neurorradiológica de pacientes com deficiência idiopática de hormônio do crescimento

“…In our sample, 10 (62.5%) of the 16 patients in which CT findings disagreed with MRI exhibited a normal CT scan and it was MRI that found abnormalities (hypoplastic anterior pituitary and ectopic posterior pituitary). One of the motives for such a high level of disagreement between the results obtained by the two methods may have been the fact that an ectopic posterior pituitary is rarely diagnosed by CT and, because MRI gives a greater degree of accuracy in identifying pituitary tissues, 5 we find variations in anterior pituitary measurements when CT is compared with MRI. One further advantage of MRI is the fact that images are obtained in multiple planes in contrast with CT in which sagittal reconstructions are created form the images, which can lead to diagnostic confusion, in particular when non-helical tomographs are used and when sections are spaced more widely apart.…”

“…[1][2][3][4][5] In certain situations, as is observed with partial hormone deficiencies, GHD diagnosis may be problematic and require laboratory investigation that is expensive, complex, and often difficult to interpret. Images obtained by MRI offer greater accuracy compared with CT, and MRI is therefore considered a better method than CT for investigating patients with GHD.…”

“…Images obtained by MRI offer greater accuracy compared with CT, and MRI is therefore considered a better method than CT for investigating patients with GHD. 5 Recent studies of children with reduced height known to have GHD, resulting from causes other than tumors, demonstrate that the principal abnormality found with MRI is hypoplastic anterior pituitary associated with an interrupted stalk and ectopic posterior pituitary, [1][2][3][4]6 this last being rarely seen with CT. 5 It is, therefore, consensus that when investigating restricted stature, the observation of a hypoplastic anterior pituitary associated with an ectopic posterior pituitary on MRI can be a strong indication of GHD. 1,3,4,11,12 Among our patients, 54% presented abnormalities on MRI and, of the abnormalities observed, a hypoplastic anterior pituitary associated with an ectopic posterior pituitary was the most common finding, being present in 70% of our cases.…”

“…In such cases, images obtained by CT and/or MRI facilitate the detection of anatomic abnormalities, which, in the majority of cases are indicators of permanent growth hormone deficiency. [1][2][3][4][5] Magnetic resonance imaging is a non-invasive method which offers greater sensitivity than CT for identification of abnormalities in the hypothalamic-pituitary region 5 and is considered useful, not just in diagnosis, but also when making treatment decisions for patients with GHD.…”

“…Previously the majority of GHD cases were diagnosed as idiopathic, but with the advent of MRI it has been possible to observe in such patients a characteristic structural anomaly described as the pituitary stalk interruption syndrome, 3,4,6,7 which is more difficult to identify with CT. 5 A number of different publications 1,3,4,6,8 have tried to correlate the morphological alterations seen with MRI with isolated growth hormone deficiency (IGHD) or as multiple anterior pituitary deficiencies (MPHD). Studies have shown that children with MPHD exhibit a higher frequency of abnormalities on MRI when compared with those that have IGHD.…”