Third-trimester in utero fetal brain diffusion tensor imaging fiber tractography: a prospective longitudinal characterization of normal white matter tract development.

BACKGROUND: White matter is responsible for inter-neuronal connections throughout the brain that are a driving force in cognitive development. Diffusion tensor imaging (DTI) fiber tractography has been used to evaluate white matter development in the fetal brain; however, longitudinal studies of DTI fiber tractography to assess white matter development in the third trimester are lacking. OBJECTIVE: To characterize in utero longitudinal changes in the fetal brain DTI fiber tracts of normal third-trimester fetuses. MATERIALS AND METHODS: For this single-center prospective longitudinal observational pilot study, we recruited 28 pregnant females with normal third-trimester pregnancies who had routine prenatal ultrasound. MRI of the in utero fetal brain was performed with a Siemens 1.5-tesla (T) Espree scanner at 31 weeks, 33 weeks and 36 weeks of gestation, with 14 DTI tractography parameters quantified in 7 brain regions using DTI-studio version 2.4 (Johns Hopkins University, Baltimore, MD; n=98 measurements). We used multilevel mixed models to examine the relationship between longitudinal changes in DTI measurements and between 98 DTI measurements at 31 weeks and 4 routine fetal brain anatomical biometrics (n=392 assessments). RESULTS: We observed statistically significant decreases in radial diffusivity and apparent diffusion coefficient in 13 of 14 brain regions from 31 weeks to 36 weeks of gestation (P<0.001 for all regions except the genu of the corpus callosum). Significant decreases in radial diffusivity from weeks 33 to 36 and weeks 31 to 36 were seen in the corticospinal tracts, centrum semiovale, posterior limb of the internal capsule, and crus cerebri (P<0.001 for all). When considering all possible combinations of DTI fiber tract measurements and the routine morphological fetal brain biometrics, only 6% (24/392) had a significant association (P<0.05), indicating relative independence of the DTI fiber tract measurements from anatomical biometrics. CONCLUSION: In utero longitudinal changes in fetal brain DTI fiber tractography are quantifiable in normal third-trimester fetuses and are largely independent of morphological brain changes.

Multidetector CT Findings in the Abdomen and Pelvis after Damage Control Surgery for Acute Traumatic Injuries.

After experiencing blunt or penetrating trauma, patients in unstable condition who are more likely to die of uncorrected shock than of incomplete injury repairs undergo emergency limited exploratory laparotomy, which is also known as damage control surgery (DCS). This surgery is part of a series of resuscitation steps, with the goal of stabilizing the patient's condition, with rapid surgical control of hemorrhage followed by supportive measures in the intensive care unit before definitive repair of injuries. These patients often are imaged with multidetector CT within 24-48 hours of the initial surgery. Knowledge of this treatment plan is critical to CT interpretation, because there are anatomic derangements and foreign bodies that would not be present in patients undergoing surgery for other reasons. Patients may have injuries beyond the surgical field that are only identified at imaging, which can alter the care plan. Abnormalities related to the resuscitation period such as the CT hypoperfusion complex and ongoing hemorrhage can be recognized at CT. Familiarity with these imaging and clinical findings is important, because they can be seen not only in trauma patients after DCS but also in other patients in the critical care setting. The interpretation of imaging studies can be helped by an understanding of the diagnostic challenges of grading organ injuries with surgical materials in place and the awareness of potential artifacts on images in these patients. Online supplemental material is available for this article. ©RSNA, 2019 See discussion on this article by LeBedis .

Liver Surface Nodularity Score Allows Prediction of Cirrhosis Decompensation and Death.

Purpose To determine whether use of the liver surface nodularity (LSN) score, a quantitative biomarker derived from routine computed tomographic (CT) images, allows prediction of cirrhosis decompensation and death. Materials and Methods For this institutional review board-approved HIPAA-compliant retrospective study, adult patients with cirrhosis and Model for End-Stage Liver Disease (MELD) score within 3 months of initial liver CT imaging between January 3, 2006, and May 30, 2012, were identified from electronic medical records (n = 830). The LSN score was measured by using CT images and quantitative software. Competing risk regression was used to determine the association of the LSN score with hepatic decompensation and overall survival. A risk model combining LSN scores (<3 or ≥3) and MELD scores (<10 or ≥10) was created for predicting liver-related events. Results In patients with compensated cirrhosis, 40% (129 of 326) experienced decompensation during a median follow-up period of 4.22 years. After adjustment for competing risks including MELD score, LSN score (hazard ratio, 1.38; 95% confidence interval: 1.06, 1.79) was found to be independently predictive of hepatic decompensation. Median times to decompensation of patients at high (1.76 years, n = 48), intermediate (3.79 years, n = 126), and low (6.14 years, n = 152) risk of hepatic decompensation were significantly different (P < .001). Among the full cohort with compensated or decompensated cirrhosis, 61% (504 of 830) died during the median follow-up period of 2.26 years. After adjustment for competing risks, LSN score (hazard ratio, 1.22; 95% confidence interval: 1.11, 1.33) and MELD score (hazard ratio, 1.08; 95% confidence interval: 1.06, 1.11) were found to be independent predictors of death. Median times to death of patients at high (0.94 years, n = 315), intermediate (2.79 years, n = 312), and low (4.69 years, n = 203) risk were significantly different (P < .001). Conclusion The LSN score derived from routine CT images allows prediction of cirrhosis decompensation and death. ©RSNA, 2016 Online supplemental material is available for this article.

Vascular Tumor Burden as a New Quantitative CT Biomarker for Predicting Metastatic RCC Response to Antiangiogenic Therapy.

Purpose To quantify initial changes in the vascular tumor burden (VTB), a measure of the area of vascularized tumor on computed tomographic (CT) images, and predict tumor response to antiangiogenic therapy in patients with metastatic renal cell carcinoma (RCC). Materials and Methods For this institutional review board-approved HIPAA-compliant secondary analysis of a prospective phase III trial, adult patients with digital CT images and metastatic clear-cell RCC treated with sunitinib were included (n = 275). Target lesions were selected by using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 guidelines, and the CT images obtained after one cycle of sunitinib therapy were evaluated in comparison with baseline images. Tumor-response software was created to quantify tumor metrics (length, area, VTB, and mean attenuation) and automate response assessment. Progression-free survival (PFS) in responders and nonresponders according to VTB criteria was compared by using the Cox proportional hazard ratio (HR). The intraclass correlation coefficient (ICC) was used to assess interobserver agreement among three readers evaluating 28 randomly selected patients. Results VTB criteria nonresponders (n = 120) according to the initial posttherapy CT study were 5.7 times more likely to experience progression of disease (HR = 5.70; 95% confidence interval [CI]: 4.07, 7.97; P < .001) than responders (n = 155). There was not a statistically significant difference in PFS between RECIST nonresponders (n = 255) and responders (n = 20; HR = 1.54; 95% CI: 0.85, 2.77; P = .148). In a patient-level analysis, interobserver agreement was very good for assessing percentage change in length, area, and VTB (ICC = 0.82 [95% CI: 0.67, 0.91], 0.89 [95% CI: 0.79, 0.94], and 0.88 [95% CI: 0.79, 0.94], respectively) but was very poor for assessing percentage change in mean attenuation (ICC = 0.17 [95% CI: -0.05, 0.45]). Conclusion A quantitative CT imaging biomarker designed to measure initial changes in the VTB separated patients into responders and nonresponders, each with significantly different PFS, and showed very good interobserver agreement in patients with metastatic RCC treated with sunitinib. © RSNA, 2016 Online supplemental material is available for this article.

Isolated unilateral absence of the right pulmonary artery.

Isolated unilateral absence of the right pulmonary artery is an uncommon congenital disorder that may remain undiagnosed for prolonged periods of time. A brief overview of isolated unilateral absence of the right pulmonary artery is presented with a description of the typical clinical and radiographic findings associated with this anomaly.

Multimodality Thoracoabdominal Imaging Findings in a Rare Case of Thoracic Endometriosis Syndrome.

Thoracic endometriosis syndrome (TES) is an extremely rare disorder, and it is defined as the presence of functional endometrial tissue in pleura, airways, and lung parenchyma. We describe a rare case of a 29-year-old nulliparous female who presented with abdominal pain, dyspareunia, and shortness of breath. She complained of worsening of symptoms around the menstrual cycle. Initial workup showed markedly elevated CA-125 levels. A chest radiograph and CT of the chest, abdomen, and pelvis demonstrated large tension hydrothorax, ascites, and bilateral ovarian cysts. A chest tube was placed to decompress the tension hydrothorax, which drained copious amounts of blood. In view of the unexplained etiology of large hemothorax and elevated CA-125 levels, an MRI of the abdomen and pelvis was performed. This revealed advanced pelvic endometriosis, a right pleural nodule, and ipsilateral hydropneumothorax. Based on these findings, a diagnosis of TES was presumed. The patient was then referred to video-assisted thoracoscopy (VATS) and continuous estrogen suppression for optimal treatment. On early follow-up, she presented with recurrent hydropneumothorax, which was successfully managed with CT-guided chest tube placement and remained stable on further follow-ups. TES diagnosis is often challenging and delayed, demanding a high index of suspicion in patients with risk factors and characteristic clinical presentation. Radiologists should be aware of key imaging findings to help in early diagnosis for timely clinical and surgical management.

Complex Case of Aggressive Intra-abdominal Desmoid-type Fibromatosis Status Post Cholecystectomy.

Desmoid-type fibromatosis (DF), also known as desmoid tumor, is an extremely rare, benign, mesenchymal fibrous tumor with no potential for metastasis. It can arise from any part of the body, most commonly extra-abdominally. Intra-abdominal DF can present sporadically, in sites of previous trauma, surgical scars and irradiation, or in association with familial adenomatous polyposis and Gardner syndrome. Intra-abdominal DF is uncommon and especially rare after a common surgery like cholecystectomy. We report a rare case of a 67-year-old male who presented with a locally aggressive intra-abdominal DF in the gallbladder fossa, status post cholecystectomy. This progressively enlarging infiltrative enhancing solid mass in the gallbladder fossa on serial computed tomography and magnetic resonance imaging demonstrated gastric outlet obstruction, biliary obstruction, portal vein narrowing and encasement of hepatic artery. Diagnosis of DF in this postoperative setting was delayed and challenging due to uncharacteristic clinical presentation. Radiologists should be aware of this unusual diagnosis and spectrum of imaging findings to help in timely surgical management and planning.

Rupture of an Infected Renal Cyst Secondary to a Renocolic Fistula in Autosomal Dominant Polycystic Kidney Disease.

We present a rare case of retroperitoneal rupture of an infected renal cyst secondary to a renocolic fistula in a patient with autosomal dominant polycystic kidney disease (ADPKD). Intraperitoneal rupture of infected cysts in ADPKD resulting in peritonitis has been described, but to our knowledge, this is the first reported case of retroperitoneal rupture. Cyst infections are a common complication of ADPKD and are difficult to treat, potentially leading to sepsis and death.

Opportunistic bone density screening for the abdominal radiologist using colored CT images: a pilot retrospective study.

PURPOSE: The purpose of the study was to develop an accurate and reproducible method for detecting low spinal bone density on abdominal CT images. METHODS: For this IRB-approved HIPAA-compliant single-center retrospective study, nonenhanced CT images of the lower abdomen were obtained in 631 African-American participants. Mean attenuation of L3/L4 was associated with quantitative CT bone density (QCT) in a randomly selected training cohort (N = 511), and receiver operating characteristics analysis was used to identify the optimal mean attenuation threshold for differentiating normal from low bone density. Custom image processing software was used to generate grayscale and colored CT images of the midline spine, with green for normal and red for low bone density. Five radiologists independently assessed bone density at L3/L4 in a validation cohort (N = 120) using various methods: QCT, visual assessment of sagittal grayscale images (Grayscale), quantitative measurement of mean attenuation on a midline sagittal image (Attenuation), and visual assessment of a midline sagittal colored image (Color). Accuracy was calculated using the average QCT bone density as a reference standard. Inter-observer agreement was assessed using intraclass correlation coefficient (ICC). RESULTS: The optimal mean attenuation threshold for differentiating normal from low bone density at L3/L4 was 145 Hounsfield Units. The average accuracy of Grayscale, Attenuation, and Color methods was 58, 87, and 91% (p < 0.001), respectively. Inter-observer agreement was poor for Grayscale (ICC: 0.20; 95% CI 0.12, 0.28) and excellent for both Attenuation (ICC: 0.85; 95% CI 0.73, 0.91) and Color methods (ICC: 0.87; 95% CI 0.83, 0.90). CONCLUSION: Detection of low spinal bone density using colored abdominal CT images was highly accurate and reproducible.

Diagnosis and interventions of vascular complications in lung transplant.

Though rare, pulmonary vascular complications after lung transplantation carry high morbidity and mortality. Knowledge of the normal and abnormal appearance of lung transplant vasculature is essential for timely and appropriate diagnosis and management of complications. Appropriate selection of surgical and endovascular treatments depend on the availability of expertise and requires a multidisciplinary approach to ensure the best outcomes.

Precision analysis of a quantitative CT liver surface nodularity score.

PURPOSE: To evaluate precision of a software-based liver surface nodularity (LSN) score derived from CT images. METHODS: An anthropomorphic CT phantom was constructed with simulated liver containing smooth and nodular segments at the surface and simulated visceral and subcutaneous fat components. The phantom was scanned multiple times on a single CT scanner with adjustment of image acquisition and reconstruction parameters (N = 34) and on 22 different CT scanners from 4 manufacturers at 12 imaging centers. LSN scores were obtained using a software-based method. Repeatability and reproducibility were evaluated by intraclass correlation (ICC) and coefficient of variation. Using abdominal CT images from 68 patients with various stages of chronic liver disease, inter-observer agreement and test-retest repeatability among 12 readers assessing LSN by software- vs. visual-based scoring methods were evaluated by ICC. RESULTS: There was excellent repeatability of LSN scores (ICC:0.79-0.99) using the CT phantom and routine image acquisition and reconstruction parameters (kVp 100-140, mA 200-400, and auto-mA, section thickness 1.25-5.0 mm, field of view 35-50 cm, and smooth or standard kernels). There was excellent reproducibility (smooth ICC: 0.97; 95% CI 0.95, 0.99; CV: 7%; nodular ICC: 0.94; 95% CI 0.89, 0.97; CV: 8%) for LSN scores derived from CT images from 22 different scanners. Inter-observer agreement for the software-based LSN scoring method was excellent (ICC: 0.84; 95% CI 0.79, 0.88; CV: 28%) vs. good for the visual-based method (ICC: 0.61; 95% CI 0.51, 0.69; CV: 43%). Test-retest repeatability for the software-based LSN scoring method was excellent (ICC: 0.82; 95% CI 0.79, 0.84; CV: 12%). CONCLUSION: The software-based LSN score is a quantitative CT imaging biomarker with excellent repeatability, reproducibility, inter-observer agreement, and test-retest repeatability.

Sirenomelia: Mermaid deformity on fetal MR imaging.

This case involves the rare congenital disorder Sirenomelia, a diagnosis initially suspected during prenatal ultrasound and later confirmed by prenatal MRI. Sirenomelia, or mermaid syndrome, is mainly characterized by variable fusion of the lower limbs and by genitourinary anomalies. The vast majority of cases of this disease result in death secondary to associated renal agenesis or hypoplasia. Imaging findings from the disease are discussed, in addition to the clinical implications and suspected etiologies of this entity.

Ectopic intracaval liver.

Congenital abnormalities of the liver are rare with prior descriptions of lobar or segmental agenesis, Reidel's lobe, and ectopic hepatic lobes. Intrathoracic ectopic hepatic lobes have been reported in many instances; however, there is only one documented case of abnormally positioned liver tissue within the inferior vena cava (J Chapman-Fredricks, R Birusingh, M Ricci, M Rodriguez, Intracaval liver with cardiac extension. A new developmental anomaly? Fetal and Pediatric Pathology. 2010; 29:401-406). We report a second case of an ectopic intracaval liver defined as a mass in an adult who presented for abdominal pain and review the radiological findings.