Clinical impact of the callosal angle in the diagnosis of idiopathic normal pressure hydrocephalus

Abstract

The utility of measuring the corpus callosal angle (CA) for the diagnosis of idiopathic normal pressure hydrocephalus (INPH) was investigated. Three-dimensional magnetic resonance imaging (MRI) was performed in 34 INPH patients, 34 Alzheimer's disease (AD) patients, and 34 normal control (NC) subjects. Measurement of the CA on the coronal MR images of the posterior commissure perpendicular to the anteroposterior commissure plane was performed for all subjects. The CA of the INPH group (mean +/- SD, 66 +/- 14 degrees) was significantly smaller than those of the AD (104 +/- 15 degrees) and NC (112 +/- 11 degrees) groups. When using the threshold of the mean - 2SD value of the NC group (= 90 degrees), an accuracy of 93%, sensitivity of 97%, and specificity of 88% were observed for discrimination of INPH from AD patients. Measuring the CA helps in differentiating INPH patients from AD and normally aged subjects.

Preoperative Prognostic Value of MRI Findings in 108 Patients with Idiopathic Normal Pressure Hydrocephalus

“…5 The results in this and a previous study of a smaller callosal angle in patients who responded to shunt surgery further support its prognostic value. 3 The significant OR Ͻ 1 for the callosal angle can be interpreted as showing that patients with a larger angle are less likely to benefit from shunt surgery.…”

“…The callosal angle measured on MR imaging is the angle between the lateral ventricles on a coronal image through the posterior commissure, perpendicular to the anterior/posterior commissure plane (Fig 1B). 5 Compression of the medial and/or high convexity cortex sulci (narrow sulci) was evaluated on coronal and transverse images. 6 It was graded as the following: 0 ϭ normal or wider than normal, 1 ϭ slight compression, 2 ϭ definitive compression (Fig 1C, -D).…”

High-Convexity Tightness Predicts the Shunt Response in Idiopathic Normal Pressure Hydrocephalus

“…19 2) The callosal angle, the angle between the left and right corpus callosum, was measured on a coronal plane at the posterior commissure. 20 3) We evaluated the tightness of the high-convexity subarachnoid space on the 4 uppermost contiguous transverse sections and the 3 contiguous coronal sections on and anterior to the posterior commissure. The severity of the high-convexity tightness was visually rated as follows: 0, dilated; 1, normal; 2, mildly tight (tightness was observed over less than three-quarters of the high- convexity space); and 3, severely tight (tightness was observed over three-quarters or more of the high-convexity space).…”

The callosal angle measured on MRI as a predictor of outcome in idiopathic normal-pressure hydrocephalus

“…All measurements were performed digitally using a clinical picture archiving and communication system (PACS) (Carestream Health). Ishii et al 11 suggested that the CA should be measured between the lateral ventricles on a coronal MR image through the posterior commissure (PC), perpendicular to the anterior commissure (AC)-PC plane. Multiplanar reconstruction was performed interactively in the PACS for each patient to obtain such a coronal image (Fig.…”

“…16,23 Ishii et al presented a method for measurement of the CA on MRI. 11 They suggested that patients with iNPH could be distinguished from those with ventricular dilation due to Alzheimer's disease by a CA of less than 90°. However, no previously published studies have clarified the usefulness of the CA as an imaging biomarker for the selection of patients with iNPH for shunt surgery.…”