Complication to consider: delayed traumatic hemothorax in older adults.

BACKGROUND: Emerging evidence suggests older adults may experience subtle hemothoraces that progress over several days. Delayed progression and delayed development of traumatic hemothorax (dHTX) have not been well characterized. We hypothesized dHTX would be infrequent but associated with factors that may aid prediction. METHODS: We retrospectively reviewed adults aged ≥50 years diagnosed with dHTX after rib fractures at two level 1 trauma centers (March 2018 to September 2019). dHTX was defined as HTX discovered ≥48 hours after admission chest CT showed either no or 'minimal/trace' HTX. Two blinded, board-certified radiologists reviewed inpatient chest imaging and classified injury patterns according to Chest Wall Injury Society (CWIS) taxonomy. Descriptive analysis was performed for demographic and hospitalization characteristics. RESULTS: We identified 14 patients with pooled dHTX rate of 1.3%. After initial chest CT negative for concerning hemothoraces, the patients did not undergo follow-up imaging until new symptoms (shortness of breath, chest pain) developed: eight (57%) were not diagnosed until after discharge from initial hospitalization (mean (range): 9 (2-20) days after discharge). Aspirin and/or anticoagulants were involved in fewer than half of cases (43%). According to CWIS taxonomy, all patients had a series of posterolateral fractures with at least one offset or displaced fracture, and an average of six consecutive rib fractures. All patients underwent tube thoracostomy and six patients (42%)-all aged <65-underwent operative interventions. DISCUSSION: Preliminary data suggest older adults with rib fractures may be at risk of experiencing delayed progression of trace hemothoraces or a delayed presentation of hemothoraces. Asymptomatic progression or readmission to other services/hospitals likely occurs and true dHTX rates are likely higher. Our preliminary findings suggest a possible anatomic explanation for severe chest wall injury patterns' association with dHTX. Further characterization and capturing the true incidence of dHTX first requires wider recognition of this complication.

Using Online Survey Software to Enhance Radiology Learning.

RATIONALE AND OBJECTIVES: Online educational modules can augment radiology learning by creating opportunities to interact with images in more dynamic ways than with static presentation of images in lectures or journal articles. Building these modules on an online survey platform allows for quantitative assessment and learner feedback, without requiring programming knowledge or need for new website creation. MATERIALS AND METHODS: Interactive online tutorials were built on a web-based survey platform (Qualtrics, Provo, Utah) accessible by computer or mobile device to teach radiology imaging findings of selected high-morbidity diagnoses. Topics included congenital-type internal hernias (module 1), acute appendicitis in the pregnant patient (module 2), and unintentionally retained surgical instruments (RSI; module 3). Modules consisted of pretest, educational module, and post-test components. For modules 1 and 2, graphics interchange formats were utilized to show CT and MRI image stacks for the diagnosis of congenital-type internal hernias and acute appendicitis in pregnant patients, respectively. For module 3, the "Heat Map" format was chosen to showcase intraoperative radiograph cases, which allowed participants to click on the potential RSI in the image. Pre- and post-test scores were evaluated. To determine statistical significance, an alpha level of 0.05 was utilized. RESULTS: Module 1 (Internal Hernia): Twenty-one radiology trainees completed the module. The mean pretest score was 3.66 (±1.13) points out of a total 6 possible points (61%), compared to 4.52 (±1.03) points on the post-test (75%). This was a statistically significant increase on the post-test of 0.87 points (95% CI [confidence interval] 0.36, 1.38), t(20) = 3.53, p= 0.002. Module 2 (MR Appendicitis): Seventeen radiology trainees completed the module. The mean pretest score was 3.18 (±1.42) points out of a total 6 possible points (53%), compared to 5.12 (±0.86) points on the post-test (85%). This was a statistically significant increase on the post-test of 1.94 points (95% CI 1.12, 2.76), t(16) = 5.00, p< 0.001. Module 3 (RSI): One hundred seven participants completed the module. The mean pretest score was 3.60 (±1.53) points out of a total 6 possible points (60%), compared to 4.54 (±1.36) points on the post-test (76%). This was a statistically significant increase on the post-test of 0.94 points (95% CI 0.67, 1.21), t(106) = 6.84, p< 0.001. CONCLUSION: An online survey platform can be used to build interactive education modules. Post-test scores significantly improved from pretest scores with these educational modules.

A review of internal hernias related to congenital peritoneal fossae and apertures.

Congenital-type internal hernias have the potential to cause small bowel obstruction well into adulthood. Congenital-type internal hernias include left paraduodenal, right paraduodenal, foramen of Winslow, pericecal, sigmoid mesocolon, transomental, small bowel mesentery, and broad ligament hernias. This review summarizes CT imaging features and complications of congenital internal hernias using a systematic approach based on abdominopelvic quadrants and key anatomic features. CT imaging will continue to be commonly used to evaluate abdominal pain. Anatomical landmarks and characteristic CT findings can help identify congenital internal hernias as a potential cause of abdominal pain.

Müllerian duct anomalies: embryological development, classification, and MRI assessment.

Müllerian duct anomalies (MDA) occur due to abnormal development of the uterus, cervix, and vagina, many times affecting a woman's ability to conceive and carry a pregnancy to term. The spectrum of possible abnormalities are related to the development of two separate Müllerian systems, which then fuse and subsequently undergo degeneration of the fused segments. This multiphasic development explains the multiple variations within the scheme of MDA classification. The purpose of this article is to review the embryologic development of the Müllerian ducts, relate the development to the most commonly used classification system, and review the magnetic resonance imaging (MRI) assessment of Müllerian duct anomalies. A brief review of the treatment options, as they relate to the imaging diagnosis, will be provided as well.

MRI of pregnancy-related issues: müllerian duct anomalies.

OBJECTIVE: Müllerian duct anomalies can adversely affect pregnancy outcomes and can result in clinical symptoms. This article will review the appropriate management of patients with müllerian duct abnormalities. CONCLUSION: Whereas uterine and vaginal septa, vaginal agenesis, and unicornuate uterus can be managed surgically, other uterine anomalies tend to be managed clinically. Hence, appropriate management depends on a reliable assessment of pelvic anatomy. MRI can accurately display female pelvic anatomy and is, therefore, useful in guiding therapy.

Symbiosis, morphology, and phylogeny of Hoplonymphidae (Parabasalia) of the wood-feeding roach Cryptocercus punctulatus.

Anaerobic cellulolytic flagellate protists of the hindguts of lower termites and the wood-feeding cockroach Cryptocercus are essential to their host's ability to digest lignocellulose. Many have bacteria associated with their surfaces and within cytoplasmic vesicles-likely important symbioses as suggested by molecular and other data. Some of the most striking examples of these symbioses are in the parabasalid family Hoplonymphidae, but little or no data exist on the structural aspects of their symbioses, their relationships with bacteria through different life-cycle stages, or their diversity and phylogenetic relationships in Cryptocercus. We investigated these areas in the hoplonymphid genera Barbulanympha and Urinympha from Cryptocercus punctulatus using light and electron microscopy, and analysis of small subunit rRNA. Microscopy reveals variation in density of bacterial surface symbionts related to life-cycle stage, a glyococalyx possibly important in bacterial adhesion and/or metabolite exchange, and putative viruses associated with bacterial surface symbionts. Patterning of surface bacteria suggests protists emerging from the resistant (dormant) stage are colonized by a small population of bacterial cells, which then divide to cover their surface. Additionally, cytoplasmic protrusions from the protist are covered by bacteria. Phylogenetic analysis rejects the monophyly of Hoplonymphidae, suggesting multiple origins or losses of these bacterial symbioses.

Computer-aided detection (CAD) of lung nodules in CT scans: radiologist performance and reading time with incremental CAD assistance.

OBJECTIVE: The diagnostic performance of radiologists using incremental CAD assistance for lung nodule detection on CT and their temporal variation in performance during CAD evaluation was assessed. METHODS: CAD was applied to 20 chest multidetector-row computed tomography (MDCT) scans containing 190 non-calcified > or =3-mm nodules. After free search, three radiologists independently evaluated a maximum of up to 50 CAD detections/patient. Multiple free-response ROC curves were generated for free search and successive CAD evaluation, by incrementally adding CAD detections one at a time to the radiologists' performance. RESULTS: The sensitivity for free search was 53% (range, 44%-59%) at 1.15 false positives (FP)/patient and increased with CAD to 69% (range, 59-82%) at 1.45 FP/patient. CAD evaluation initially resulted in a sharp rise in sensitivity of 14% with a minimal increase in FP over a time period of 100 s, followed by flattening of the sensitivity increase to only 2%. This transition resulted from a greater prevalence of true positive (TP) versus FP detections at early CAD evaluation and not by a temporal change in readers' performance. The time spent for TP (9.5 s +/- 4.5 s) and false negative (FN) (8.4 s +/- 6.7 s) detections was similar; FP decisions took two- to three-times longer (14.4 s +/- 8.7 s) than true negative (TN) decisions (4.7 s +/- 1.3 s). CONCLUSIONS: When CAD output is ordered by CAD score, an initial period of rapid performance improvement slows significantly over time because of non-uniformity in the distribution of TP CAD output and not to a changing reader performance over time.

Morphology, phylogeny, and diversity of Trichonympha (Parabasalia: Hypermastigida) of the wood-feeding cockroach Cryptocercus punctulatus.

Trichonympha is one of the most complex and visually striking of the hypermastigote parabasalids-a group of anaerobic flagellates found exclusively in hindguts of lower termites and the wood-feeding cockroach Cryptocercus-but it is one of only two genera common to both groups of insects. We investigated Trichonympha of Cryptocercus using light and electron microscopy (scanning and transmission), as well as molecular phylogeny, to gain a better understanding of its morphology, diversity, and evolution. Microscopy reveals numerous new features, such as previously undetected bacterial surface symbionts, adhesion of post-rostral flagella, and a distinctive frilled operculum. We also sequenced small subunit rRNA gene from manually isolated species, and carried out an environmental polymerase chain reaction (PCR) survey of Trichonympha diversity, all of which strongly supports monophyly of Trichonympha from Cryptocercus to the exclusion of those sampled from termites. Bayesian and distance methods support a relationship between Trichonympha species from termites and Cryptocercus, although likelihood analysis allies the latter with Eucomonymphidae. A monophyletic Trichonympha is of great interest because recent evidence supports a sister relationship between Cryptocercus and termites, suggesting Trichonympha predates the Cryptocercus-termite divergence. The monophyly of symbiotic bacteria of Trichonympha raises the intriguing possibility of three-way co-speciation among bacteria, Trichonympha, and insect hosts.

Split-bolus MDCT urography with synchronous nephrographic and excretory phase enhancement.

OBJECTIVE: Our purpose was to evaluate the utility of CT urography performed using a split contrast bolus that yields synchronous nephrographic and excretory phase enhancement. MATERIALS AND METHODS: Five hundred consecutive patients referred for evaluation of possible urinary tract abnormalities (327 for painless hematuria) underwent CT urography with unenhanced scanning of the abdomen and pelvis and scanning during concurrent nephrographic and excretory phase enhancement produced by administration of a split contrast bolus. The enhanced abdomen scan was obtained with abdominal compression; the enhanced pelvis scan was obtained after release of compression. Findings from axial sections and coronal maximum intensity projections were correlated with clinical follow-up and, as available, with laboratory and other imaging studies including cystoscopy, ureteroscopy, urine cytology, surgery, and pathology. Follow-up management for each patient was determined by the clinical judgment of the referring physician. RESULTS: CT urography identified 100% of pathologically confirmed renal cell carcinomas (n = 10) and uroepithelial malignancies involving the renal collecting system or ureter (n = 8). An additional nine renal masses were identified for which no pathologic proof has yet been obtained, including eight subcentimeter solid renal masses and one multiloculated lesion. Fourteen of 19 confirmed cases of uroepithelial neoplasm involving the bladder were identified. CT urography yielded one false-positive for bladder tumor, two false-positives for ureteral tumor, and one patient with a bladder mass who refused further evaluation. CT urography yielded sensitivity and specificity of 100% and 99% and 74% and 99% and positive predictive value and negative predictive value of 80% and 100% and 93% and 99% for the renal collecting system and ureter and bladder, respectively. CT urography was ineffective in identifying 11 cases of noninfectious cystitis. CT urography also depicted numerous other congenital and acquired abnormalities of the urinary tract. CONCLUSION: Split-bolus MDCT urography detected all proven cases of tumors of the upper urinary tract, yielding high sensitivity and specificity. The split-bolus technique has the potential to reduce both radiation dose and the number of images generated by MDCT urography.

Vascular mapping of the leg with multi-detector row CT angiography prior to free-flap transplantation.

PURPOSE: To retrospectively evaluate multi-detector row computed tomographic (CT) angiography in determining donor- and recipient-site arterial suitability for successful vascularized free-flap transplantation. MATERIALS AND METHODS: The institutional review board granted approval; informed consent was waived, and the study was HIPAA compliant. Lower extremities of 20 (12 male, eight female; mean age, 51 years; range, 10-84 years) patients undergoing vascularized free-flap procedures were examined at multi-detector row CT angiography. In five patients, legs were assessed as potential fibular free-flap donors for mandibular, maxillary, or radial reconstruction. In 15 patients, legs were assessed as recipient sites for free flaps. Vascular maps obtained with volume rendering, maximum intensity projections, and curved planar reformations were generated, and assessment was made in the depiction of calf vessels and presence of stenosis, occlusion, and anatomic anomaly. Findings of CT angiography, physical examination, and surgery were compared, where applicable, and successful CT-based prediction of the surgical intervention was assessed. Immediate and long-term (>70 days) viability of the graft was assessed in all patients. RESULTS: CT angiography depicted the entirety of all four major calf arteries in 29 of 32 legs scanned. In three legs, external-fixation hardware obscured some segments. There were no discrepancies between CT findings and those identified at the time of surgery. Arterial abnormalities, including stenosis, occlusion, and variant anatomy, were seen in 12 lower extremities in 10 patients. Only two were suspected on the basis of physical examination findings. In five of 20 patients, CT findings resulted in changes to the surgical plan. There was a 100% immediate viability of all grafts, which remained well vascularized between 70 days and 37 months after the procedure. CONCLUSION: Multi-detector row CT angiography provides a noninvasive means of preoperatively assessing lower extremity arteries for abnormalities, which could jeopardize graft viability or pedal arterial supply after free-flap procedures.

Measurement of renal extraction fraction with contrast-enhanced CT.

Study was approved by the institutional review board, and informed patient consent was waived. A method for minimization of sources of variability in measuring single-kidney extraction fraction (EF) was determined retrospectively with contrast material-enhanced computed tomography (CT). Ten adults underwent CT of the kidneys; precontrast scans were obtained, followed by postcontrast scanning 2 minutes after contrast material injection. Single-kidney EF was then calculated for each patient with the formula EF = (CT(A) - CT(V))/(CT(A) - CT(PRE)), where CT(A) and CT(V) are the postcontrast CT values (in Hounsfield units) of the systemic blood and renal venous blood, respectively, and CT(PRE) is the precontrast CT value of the blood. Both conventional two-dimensional and volumetric three-dimensional regions of interest were used for determining mean CT values of the blood. By using the volumetric regions of interest, left and right renal EF values averaged 17.3% and 18.0%, respectively, for two observers, compared with the accepted value of 15%-20%. This latter technique also minimized right-left kidney and interobserver variability in the measurement of EF.

Estimation of renal extraction fraction based on postcontrast venous and arterial differential T1 values: an error analysis.

An error analysis for quantifying single kidney extraction fraction (EF) via differential T1 measurements in the renal vein (RV) and renal artery (RA) is presented. Sources of error include blood flow effects, the effect of a short repetition time (TR), and the impact of uncertainties in the T1 estimates on the final EF calculations. Blood flow effects were investigated via simulation. For a range of blood velocities in the renal vein that may be found in kidney disease, incomplete refreshment of blood between readouts results in significant errors in T1 estimation. For a .5-cm slice, 110-ms sampling interval, and T1 of 600 ms, T1 estimation to within 5% of true T1 requires an average through-plane velocity of 6.75 cm/s for parabolic flow, and 3.5 cm/s for plug flow. Improvement can be achieved by accurately estimating the fraction of blood that has not refreshed between readouts (f(old)), while the quality of the T1 estimate varies with the accuracy of f(old) estimation. Shortening of the TR was investigated using phantom and in vivo studies. T1 was estimated to within 3% of the true value on phantoms, and within 5% of the true value for flowing blood for TR = 2T1. The estimated EF is shown to be very sensitive to the difference between T(1RA) and T(1RV). To achieve 10% or 20% uncertainty in the EF estimate, T1 in the renal vein and renal artery must be estimated to within approximately 1% or 2%. Because of limitations on measurement accuracy and precision, this method appears to be impractical at this time.

The sonographic features of papillary thyroid carcinomas: pictorial essay.

Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy in children and adults, with an incidence of 22,000 cases per year in the United States. Differentiating PTC from more frequently occurring benign thyroid nodules has proved challenging as there may be significant overlap in their clinical presentation and sonographic appearance. That said, high-resolution ultrasound provides a safe and affordable way of identifying and characterizing thyroid nodules and guiding percutaneous biopsies. Although no single sonographic feature is pathognomonic for PTC, certain features should raise suspicion and the combination of several features may be even more suggestive. In this pictorial essay, we describe the high-resolution sonographic features of pathologically proven PTCs. The nodule number, echo texture, internal architecture, calcifications, margins, contours, vascularity, and lymph nodes are considered. While the classic sonographic description of PTC is a solitary, hypoechoic solid nodule with microcalcifications and intrinsic vascularity, in practice, PTC may manifest with a myriad of sonographic appearances making biopsy necessary for a definitive diagnosis.

Pulmonary nodules on multi-detector row CT scans: performance comparison of radiologists and computer-aided detection.

PURPOSE: To compare the performance of radiologists and of a computer-aided detection (CAD) algorithm for pulmonary nodule detection on thin-section thoracic computed tomographic (CT) scans. MATERIALS AND METHODS: The study was approved by the institutional review board. The requirement of informed consent was waived. Twenty outpatients (age range, 15-91 years; mean, 64 years) were examined with chest CT (multi-detector row scanner, four detector rows, 1.25-mm section thickness, and 0.6-mm interval) for pulmonary nodules. Three radiologists independently analyzed CT scans, recorded the locus of each nodule candidate, and assigned each a confidence score. A CAD algorithm with parameters chosen by using cross validation was applied to the 20 scans. The reference standard was established by two experienced thoracic radiologists in consensus, with blind review of all nodule candidates and free search for additional nodules at a dedicated workstation for three-dimensional image analysis. True-positive (TP) and false-positive (FP) results and confidence levels were used to generate free-response receiver operating characteristic (ROC) plots. Double-reading performance was determined on the basis of TP detections by either reader. RESULTS: The 20 scans showed 195 noncalcified nodules with a diameter of 3 mm or more (reference reading). Area under the alternative free-response ROC curve was 0.54, 0.48, 0.55, and 0.36 for CAD and readers 1-3, respectively. Differences between reader 3 and CAD and between readers 2 and 3 were significant (P < .05); those between CAD and readers 1 and 2 were not significant. Mean sensitivity for individual readings was 50% (range, 41%-60%); double reading resulted in increase to 63% (range, 56%-67%). With CAD used at a threshold allowing only three FP detections per CT scan, mean sensitivity was increased to 76% (range, 73%-78%). CAD complemented individual readers by detecting additional nodules more effectively than did a second reader; CAD-reader weighted kappa values were significantly lower than reader-reader weighted kappa values (Wilcoxon rank sum test, P < .05). CONCLUSION: With CAD used at a level allowing only three FP detections per CT scan, sensitivity was substantially higher than with conventional double reading.

Parallel imaging of the abdomen.

Parallel imaging holds great potential for improving the quality of diagnostic abdominal MRI. The increased imaging speed afforded by parallel imaging can be translated into the obvious benefits of reduced scan time with set resolution and coverage, improved spatial resolution with set imaging time and coverage, increased anatomic coverage for a set imaging time and resolution, or some combination of the above. Additionally, the reduction in scan time can also allow some sequences that normally require multiple breath-holds to be performed with only one, or simply make breath-hold imaging possible for more patients. The decreased echo-train length allows for truer T2-weighting, less magnetic susceptibility artifact, and less blurring with echo-train imaging. Dynamic contrast-enhanced sequences can be acquired with improved temporal or spatial resolution. All of these potential advantages come with the trade-off of decreased signal-to-noise ratio, but for many patients, the benefits far outweigh the drawbacks and can vastly improve the diagnostic quality of abdominal MRI.

Measurement of renal extraction fraction using contrast-enhanced computed tomography.

Renal extraction fraction (EF) is the percentage of plasma entering the glomerulus which is filtered. Contrast agents which are freely filtered and neither secreted nor reabsorbed, may be used as markers for renal filtration, allowing EF to be calculated from computed tomography (CT) measurements of systemic vessels and renal veins. CT scans of 10 adult patients having no known renal disease were studied in this manner, giving EF values averaging 12.6% and 12.3% for the right and left kidneys, respectively, compared to the accepted value of 15%-20%. EF measurement using CT may provide noninvasive evaluation of renal function, complementing CT-derived morphologic information.