Increased hippocampal tail volume predicts depression status and remission to anti-depressant medications in major depression.

Studies of patients with major depressive disorder (MDD) have consistently reported reduced hippocampal volumes; however, the exact pattern of these volume changes in specific anatomical subfields and their functional significance is unclear. We sought to clarify the relationship between hippocampal tail volumes and (i) a diagnosis of MDD, and (ii) clinical remission to anti-depressant medications (ADMs). Outpatients with nonpsychotic MDD (n=202) based on DSM-IV criteria and a 17-item Hamilton Rating Scale for Depression (HRSD17) score ⩾16 underwent pretreatment magnetic resonance imaging as part of the international Study to Predict Optimized Treatment for Depression (iSPOT-D). Gender-matched healthy controls (n=68) also underwent MRI scanning. An automated pipeline was used to objectively measure hippocampal subfield and whole brain volumes. Remission was defined as an HRSD17 of ⩽7 following 8 weeks of randomized open-label treatment ADMs: escitalopram, sertraline or venlafaxine-extended release. After controlling for age and total brain volume, hippocampal tail volume was larger in the MDD cohort compared to control subjects. Larger hippocampal tail volume was positively related to clinical remission, independent of total hippocampal volume, total brain volume and age. These data provide convergent evidence of the importance of the hippocampus in the development or treatment of MDD. Hippocampal tail volume is proposed as a potentially useful biomarker of sensitivity to ADM treatment.

Motion-compensation techniques in neonatal and fetal MR imaging.

SUMMARY: Fetal and neonatal MR imaging is increasingly used as a complementary diagnostic tool to sonography. MR imaging is an ideal technique for imaging fetuses and neonates because of the absence of ionizing radiation, the superior contrast of soft tissues compared with sonography, the availability of different contrast options, and the increased FOV. Motion in the normally mobile fetus and the unsettled, sleeping, or sedated neonate during a long acquisition will decrease image quality in the form of motion artifacts, hamper image interpretation, and often necessitate a repeat MR imaging to establish a diagnosis. This article reviews current techniques of motion compensation in fetal and neonatal MR imaging, including the following: 1) motion-prevention strategies (such as adequate patient preparation, patient coaching, and sedation, when required), 2) motion-artifacts minimization methods (such as fast imaging protocols, data undersampling, and motion-resistant sequences), and 3) motion-detection/correction schemes (such as navigators and self-navigated sequences, external motion-tracking devices, and postprocessing approaches) and their application in fetal and neonatal brain MR imaging. Additionally some background on the repertoire of motion of the fetal and neonatal patient and the resulting artifacts will be presented, as well as insights into future developments and emerging techniques of motion compensation.