The Utility of Short-Interval Follow-Up for Baseline High-Risk Screening Breast MRI.

OBJECTIVE: Patients with a high lifetime risk of developing breast cancer undergo annual screening magnetic resonance imaging (MRI) starting at age 30. A proportion of these patients are subsequently required to undergo short-interval follow-up MRI 6 months after their baseline examination. The purpose of this study was to evaluate the utility and outcome of these short-interval follow-up examinations in this population. METHODS: A retrospective review was performed of 523 patients who received their baseline high-risk breast screening MRI at our institution between 2013 and 2017. The proportion of patients who received a short-interval follow-up MRI at 6 months was recorded. The findings at baseline and follow-up MRI were recorded, as well as the outcomes and results of any interventions performed. RESULTS: Ninety-six (17.6%) patients (age range: 25-67, mean age: 41) received a short-interval follow-up MRI following their baseline screening examination. Indications for follow-up included moderate to marked background parenchymal enhancement, nonmass enhancement, and likely benign enhancing mass. Of the 92 patients, 5 (5.4%) went on to have a biopsy, with none revealing a malignant pathology. The remainder either returned to routine screening (91.3%) or received further imaging in the form of ultrasound or additional follow-up MRI (3.3%). CONCLUSION: Short-interval follow-up breast MRI in high-risk patients after a baseline screening study with likely benign findings is unlikely to yield clinically significant findings. This retrospective study can be considered a starting point for additional future work looking at the rate, indications, and yield of short-interval follow-up following baseline high-risk screening breast MRI studies.

Validation of Region of Interest Measurements for the Objective Assessment of Post-Contrast Enhancement of Renal Lesions on MRI.

OBJECTIVE: The aim of this study was to validate the use of region of interest (ROI) measurements in MRI to objectively assess for enhancement in suspected solid renal masses and to determine a minimum threshold value for true enhancement. METHODS: Contrast-enhanced renal MRI studies performed between January 2015 and December 2017 for patients with a known renal mass who had subsequent biopsy, or partial/radical nephrectomy were included. Two body imaging fellows independently measured the mean ROI values of renal masses, normal renal parenchyma, the ipsilateral psoas muscle and external air on the pre- and post-contrast sequences. The absolute and percentage changes in the mean ROI values were calculated. The readers were blinded to the pathology results. RESULTS: 104 patients were included in this study (mean age of 65 years; 58 males and 46 females). 74 patients (71%) had a diagnosis of renal cell carcinoma (RCC). Pathology showed clear-cell RCC in 55%, papillary RCC in 22%, and other RCC subtypes in 23%. There were 30 non-RCC renal lesions (29%), including oncocytoma, renal papillary adenoma, and renal metastasis.The minimum percentage change in ROI values in the pre- versus post-contrast images for all pathology-proven RCCs was 23% (range: 23-437%, mean: 143%); this represents relative enhancement and was referred to as the Signal Intensity Index (SII). The percentage change for normal renal parenchyma ranged from 32-317%. The maximum percentage change in ROI values for pathology proven renal cysts was 13% (range: -5-13%, mean: 3.5%). There was excellent inter observer agreement between the two readers [Intra-class correlation coefficient (r) 0.81]. CONCLUSION: The percentage change in ROI values (SII) can be a helpful tool in the objective assessment of true enhancement of renal masses and can supplement subtraction images. The minimum threshold for enhancement in our study was 23%. ADVANCES IN KNOWLEDGE: Enhancement of a renal lesion can be determined using the objective tool of ROI measurements in the pre- and post-contrast MR images with a percentage change of 20% or above indicating enhancement. This is an additional objective tool, which in conjunction with the subtraction images may improve detection and appropriate diagnosis of renal lesions. It could also be helpful in cases where the subtraction images are degraded by motion artefact.

Pelvic congestion syndrome due to agenesis of the infrarenal inferior vena cava.

The inferior vena cava (IVC) is the main conduit of venous return to the right atrium from the lower extremities and abdominal organs. Agenesis of the IVC has an incidence of <1% in the general population [1], although it has been reported in the literature as occurring in up to 8.7% of the population [2]. Patients with absent IVC may present with symptoms of lower extremity venous insufficiency [6], idiopathic deep venous thrombosis [7], or pelvic congestion syndrome. To our knowledge there have only been a few cases reported in the literature of agenesis of the IVC associated with pelvic congestion syndrome [3,10,11]. We present another interesting case of pelvic congestion syndrome due to absent IVC.

Magnetic resonance imaging findings in ovarian torsion post in vitro fertilization.

Patients who get pregnant after being treated with in vitro fertilization (IVF) are at significantly increased risk of ovarian torsion compared to the general population and also in comparison to patients who get pregnant normally [1,2]. The risk is further increased in patients who develop ovarian hyperstimulation syndrome [1]. This possibility should be considered in this group of patients presenting with acute abdominal pain and immediate management should be commenced. Here, we report 2 patients who received treatment for infertility with IVF and developed ovarian torsion and we discuss their management including the imaging workup. The first case is a 34-year-old woman at 11 + 3 weeks of gestation after IVF who presented with a 12-hour acute right lower abdominal pain with nausea and vomiting. She underwent an ultrasound examination and then further evaluated with magnetic resonance imaging which showed asymmetric enlargement of the right ovary and stromal edema and a diagnosis of ovarian torsion was made. The patient underwent laparoscopic detortion and the ovary was salvaged. The second case is a 33-year-old woman at 9 weeks of gestation after IVF who presented with intermittent abdominal pain, vaginal bleeding, and nausea and vomiting for 5 days but became worse on the fifth day. Ultrasound and subsequently magnetic resonance imaging were performed which confirmed hyperstimulation syndrome. Abnormal location of the left ovary anterior to the uterus with higher volume as well as the clinical progression raised the possibility of ovarian torsion and prompted a diagnostic laparoscopy which showed right ovarian torsion and detortion was performed.