Using multiple images and contours for deformable 3D-2D registration of a preoperative CT in laparoscopic liver surgery.

PURPOSE: Laparoscopic liver resection is a challenging procedure because of the difficulty to localise inner structures such as tumours and vessels. Augmented reality overcomes this problem by overlaying preoperative 3D models on the laparoscopic views. It requires deformable registration of the preoperative 3D models to the laparoscopic views, which is a challenging task due to the liver flexibility and partial visibility. METHODS: We propose several multi-view registration methods exploiting information from multiple views simultaneously in order to improve registration accuracy. They are designed to work on two scenarios: on rigidly related views and on non-rigidly related views. These methods exploit the liver's anatomical landmarks and texture information available in all the views to constrain registration. RESULTS: We evaluated the registration accuracy of our methods quantitatively on synthetic and phantom data, and qualitatively on patient data. We measured 3D target registration errors in mm for the whole liver for the quantitative case, and 2D reprojection errors in pixels for the qualitative case. CONCLUSION: The proposed rigidly related multi-view methods improve registration accuracy compared to the baseline single-view method. They comply with the 1 cm oncologic resection margin advised for hepatocellular carcinoma interventions, depending on the available registration constraints. The non-rigidly related multi-view method does not provide a noticeable improvement. This means that using multiple views with the rigidity assumption achieves the best overall registration error.

Unprovoked piriformis myositis presenting in a pregnant patient.

A patient in her mid-30s presented to hospital at 25 weeks' gestation with acute onset of leg pain.Routine investigations were performed to rule out the common causes of leg and back pain in pregnancy, which were grossly normal. Piriformis pyomyositis was diagnosed on MRI and a collection was drained. Following an initial response to antibiotic therapy, the patient delivered by elective caesarean section, but the pain returned on postnatal day 2 and muscle inflammation was diagnosed again, requiring a repeat course of antibiotics.This case highlights a rare cause of leg pain in a pregnant patient, and the additional complexities of managing cases in the obstetric population.

Struma Ovarii: A Thyroxine-Producing Ovarian Tumor in Pregnancy.

Struma ovarii is a rare dermoid tumor that consists of more than 50% thyroid tissue. The incidence of struma ovarii is reported to be 1% of all ovarian tumors and 2-5% of all ovarian teratomas. The authors present a case of struma ovarii diagnosed during the first trimester of pregnancy in a primigravida patient and discuss the clinical presentation, diagnosis, and management options for such rare tumors, both in and outside of pregnancy.

Uterine didelphys: diagnosis, management and pregnancy outcome.

This report addresses and discusses two cases of uterine didelphys in pregnancy. The first case describes the diagnosis, management and subsequent pregnancies in a 28-year-old woman, para 2, with known didelphys uterus, left-obstructed hemi-vagina and ipsilateral renal agenesis. This uterine anomaly was diagnosed at 13 years of age, after pelvic imaging identified a haematocolpos and two uteri. To drain this haematocolpos, a hymenectomy was performed. In the second case, an incidental finding of uterine didelphys and vaginal septum in a 28-year-old primigravida is described. Both patients delivered healthy male infants at term via emergency and planned lower segment caesarean sections, indicating women with major uterine anomalies can have successful obstetric outcomes.