Too Much on Your "Plate"? Spectrum of Pathologies Involving the Tectal Plate.

The tectal plate comprises the posterior portion of the midbrain, borders the quadrigeminal cistern, and includes the superior and inferior colliculi. Benign and malignant pathologies occurring in this location may lead to aqueductal stenosis, obstructive hydrocephalus, and Parinaud syndrome. Both computed tomography and magnetic resonance imaging can be used to further characterize lesions involving the tectal plate. In this pictorial essay, we review various tectal plate lesions and their imaging features.

Discrepancy in fetal head biometry between ultrasound and MRI in suspected microcephalic fetuses.

Background Microcephaly is one of the most common fetal structural abnormalities, and prenatal microcephaly is considered a group I malformation of cortical development diagnosed according to ultrasound (US) skull measurements. Purpose To evaluate the agreement between fetal head US and magnetic resonance imaging (MRI) biometric measurements of suspected microcephalic fetuses. Material and Methods This institutional review board-approved retrospective study with waived informed consent included 180 pregnant women and was conducted at our medical center from March 2011 to April 2013. Biparietal diameter (BPD) and occipitofrontal diameter (OFD) results of fetal head US normograms were compared to normograms for MRI. We used Pearson and Spearman rho non-parametric correlation coefficients to assess the association between two quantitative variables, paired t-test for paired quantitative variables, and McNemar test for paired qualitative variables. Results The average BPD but not the average OFD percentiles in fetal head US differed significantly from the MRI results ( P < 0.0001). When looking at the accepted microcephaly threshold, both BPD and OFD percentiles differed significantly from MRI ( P < 0.0001 and P < 0.004, respectively). There was no correlation between US-measured skull biometry and MRI-measured brain biometry. Estimated cerebrospinal fluid volumes were significantly lower in the study group compared to 120 fetuses with normal findings in prenatal head US and MRI. Also, we have created a MRI-based normogram of fetal head circumference and gestational age. Conclusion The diagnosis of microcephaly by US alone may be insufficient and ideally should be validated by MRI before a final diagnosis is established.

Magnetic resonance imaging (MRI) evaluation of residual breast tissue following mastectomy and reconstruction with silicone implants.

PURPOSE: We present our use of magnetic resonance (MR) measurement to determine the amount of residual breast tissue (RBT) following total mastectomy with reconstruction. METHODS: Breast MR images of 45 women who underwent surgery between January and November 2011 were reviewed. The cohort included therapeutic and prophylactic mastectomies. RBT was evaluated at four points with a digital caliper assessing T2-weighted and T1-weighted images. RESULTS: Patients undergoing mastectomy for carcinoma tended to have less RBT than in prophylactic surgery. Greater age and recent surgery both correlated with larger RBT. CONCLUSIONS: Variable thickness of RBT is demonstrable following mastectomy and implant reconstruction using MR imaging.