Hepatic perfusional changes on CT and MRI: a radiology primer.

Hepatic perfusional changes are common in response to, or as a result of, a multitude of pathological processes. These can be neoplastic, inflammatory, fibrotic, or ischemic in origin, to name a few. The liver, having a dual blood supply, is a unique organ to study using contrast-enhanced CT and MRI imaging due to its varied appearance on multiphasic imaging. Knowledge of the CT and MRI appearance of hepatic perfusional changes, in addition to the clinical presentation, can often result in an accurate differential diagnosis. Many of the conditions that cause these changes in hepatic blood flow result in similar appearances on imaging. As a result, it is important that radiologists be aware of common pitfalls when dealing with hepatic perfusional changes to prevent misdiagnosis or delayed diagnosis. As such, this review will focus on some of the various causes of hepatic perfusional changes and how to accurately identify and diagnose them based on their CT and MRI appearance.

Prospective evaluation of the value of dynamic contrast enhanced (DCE) imaging for prostate cancer detection, with pathology correlation.

INTRODUCTION: The aim of this study was to evaluate the value of dynamic contrast enhanced (DCE) imaging in multi-parametric prostate MRI (mpMRI) for the detection and staging of prostate cancer in comparison with T2W and DWI images alone in biparametric MRI (bpMRI) in treatment naïve patients. MATERIALS AND METHODS: One hundred consecutive patients who underwent a prostate MRI at our institution from June-August 2017, as well as a systematic ultrasound-guided prostate biopsy or prostatectomy, were included. Strictly following PIRADSv2, the MRI studies were independently interpreted by a body radiologist and a body-imaging fellow on two different occasions 8-10 weeks apart. Initially, with all mpMRI sequences and then without the DCE sequence (bpMRI). The readers were blinded to the clinical information. Ethics approval was obtained. RESULTS: One hundred treatment-naïve patients were included (median age 64, age range 48-81, mean PSA 10.3). There was almost perfect intra-observer agreement for mpMRI versus bpMRI for both readers [Cohen's Kappa (k) 0.88-0.86] and substantial inter-observer agreement (k = 0.74 for mpMRI and 0.76 for bpMRI). The sensitivity and specificity did not significantly change between multi-parametric and bi-parametric MRI (Sensitivity 91.7% and 90%, Specificity of 85.5% and 85% for mpMRI and bpMRI, respectively). CONCLUSION: Based on our findings, prostate MRI without DCE (bpMRI) is of comparable diagnostic accuracy to mpMRI in treatment-naïve patients. Performing prostate MRI without DCE (bpMRI) will reduce acquisition time, decrease cost and potentially improve patient safety.

Parasitic Liver Infections: Imaging Findings and Strategies for Timely Diagnosis.

There are a number of parasitic infections that can affect the liver and biliary tree. These infections can be primarily related to the liver or can include secondary hepatic involvement. Imaging can narrow down the differential diagnosis in the appropriate clinical setting, and can even clinch the diagnosis with some pathognomonic findings. The various imaging modalities can also identify disease extent, help guide management, and demonstrate response to treatment. This pictorial essay will give an overview of parasitic liver infections, and will discuss the best imaging strategies and the key imaging features to help make a timely accurate diagnosis.

Cross-sectional pictorial review of IgG4-related disease.

Immunoglobulin G4-related disease (IgG4-RD) is an autoimmune disorder characterized by the infiltration of one or more organs with IgG4-positive plasma cells resulting in inflammatory lesions and fibrosis. Although the pancreas is the most commonly affected organ, involvement of extrapancreatic organs is an increasingly recognized manifestation of the disease. Patients may be asymptomatic and serum IgG4 concentrations may be elevated or normal. Treatment consists of glucocorticosteroid treatment, with excellent response. A definitive diagnosis requires histopathology with imaging playing a key role in avoiding treatment delays. This pictorial review will focus on the most current knowledge regarding IgG4-RD including its common and less common manifestations and the roles of multidetector CT, MRI and ultrasound in the diagnosis and management of suspected IgG4-RD. Knowledge of the varied imaging findings of this multi systemic disease is essential for radiologists to avoid misdiagnosis and assist with timely and effective treatment.

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.

Predicting Malignancy Risk of Screen-Detected Lung Nodules-Mean Diameter or Volume.

OBJECTIVE: In lung cancer screening practice low-dose computed tomography, diameter, and volumetric measurement have been used in the management of screen-detected lung nodules. The aim of this study was to compare the performance of nodule malignancy risk prediction tools using diameter or volume and between computer-aided detection (CAD) and radiologist measurements. METHODS: Multivariable logistic regression models were prepared by using data from two multicenter lung cancer screening trials. For model development and validation, baseline low-dose computed tomography scans from the Pan-Canadian Early Detection of Lung Cancer Study and a subset of National Lung Screening Trial (NLST) scans with lung nodules 3 mm or more in mean diameter were analyzed by using the CIRRUS Lung Screening Workstation (Radboud University Medical Center, Nijmegen, the Netherlands). In the NLST sample, nodules with cancer had been matched on the basis of size to nodules without cancer. RESULTS: Both CAD-based mean diameter and volume models showed excellent discrimination and calibration, with similar areas under the receiver operating characteristic curves of 0.947. The two CAD models had predictive performance similar to that of the radiologist-based model. In the NLST validation data, the CAD mean diameter and volume models also demonstrated excellent discrimination: areas under the curve of 0.810 and 0.821, respectively. These performance statistics are similar to those of the Pan-Canadian Early Detection of Lung Cancer Study malignancy probability model with use of these data and radiologist-measured maximum diameter. CONCLUSION: Either CAD-based nodule diameter or volume can be used to assist in predicting a nodule's malignancy risk.

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.

Hepatic epithelioid angiomyolipoma with renal metastasis: radiologic-pathologic correlation.

Epithelioid angiomyolipoma (EAML) is a rare subtype of angiomyolipomas. Unlike the conventional angiomyolipomas, EAML often contains minimal fat which usually precludes prospective diagnosis on imaging. The imaging findings of EAML may overlap with other benign and malignant hepatic neoplasms. We report a hepatic epithelioid angiomyolipoma in a 47-year-old female which metastasized to the right kidney and recurred after resection in the liver. We analyze the imaging findings of EAML on ultrasound, computed tomography, positron emission tomography and magnetic resonance imaging. Correlation between the imaging and histopathologic findings is made. The estimated annual growth and doubling time of the primary hepatic EAML are calculated. To the best of our knowledge, this is the first published report of positron emission tomography-computed tomography findings and annual growth rate for hepatic EAML.

Change in diffusion weighted MRI during liver cancer radiotherapy: preliminary observations.

PURPOSE: To evaluate diffusion weighted magnetic resonance imaging (DWI) in liver and liver cancers during and following conformal radiotherapy (RT). To determine the feasibility of using changes in apparent diffusion coefficients (ADC) as a potential surrogate for tumour control or normal tissue injury. MATERIALS AND METHODS: Patients on a six-fraction conformal liver RT protocol underwent DW-MRI at the time of treatment planning, during RT (week one and two) and one month following RT. Diffusion weighted MR images were acquired in exhale breath hold, using b-values of 0 and 600. Regions of interest (ROIs) corresponding to maximal tumour dose, high-dose peri-tumour liver, irradiated normal liver, non-irradiated liver, and spleen were analyzed on ADC maps. RESULTS: Eleven patients (four hepatocellular carcinoma, five liver metastases, two cholangiocarcinoma) were evaluated. The baseline median tumour ADC of 1.56 x 10(-3)mm(2)/sec increased to 1.89 x 10(-3)mm(2)/sec at RT week one, to 1.91 x 10(-3)mm(2)/sec during week two and to 2.01 x 10(-3)mm(2)/sec at one month following treatment (p < 0.0001). Early increases in mean ADC were correlated with higher dose and sustained tumour response, whereas RECIST and volume changes on T2 images were not. Peri-tumour mean ADC also increased, from 1.40 x 10(-3)mm(2)/sec (baseline) to 1.55 x 10(-3)mm(2)/sec (RT week 2) and 1.64 x 10(-3)mm(2)/sec (follow-up). Small ADC changes were seen in the irradiated liver, and no significant changes were seen in the un-irradiated liver. CONCLUSIONS: Changes in tumour ADC were seen during RT. Larger increases were correlated with higher doses and increased likelihood of response.

Serial repositioning of a Günther tulip retrievable inferior vena cava filter in a pediatric patient.

We report an 11-year-old boy who required inferior vena cava (IVC) filtration for a prolonged period of time. A retrievable IVC filter was placed and repositioned three times, providing a total of 60 days of IVC filtration. The filter was removed when his risk of pulmonary embolus had decreased substantially. This is a relatively uncommon practice in the pediatric population. The technique is presented, and the available literature is reviewed.