Cameron Hassani

Diabetic ketoacidosis in a child on FK506 immunosuppression after a liver transplant.

The use of immunosuppressive agents is becoming more widespread, especially in the context of organ transplantation. We report a child with a complication, new-onset diabetes mellitus with diabetic ketoacidosis, associated with the use of one such agent, FK506 (tacrolimus).

A case of multisystem endometriosis.

Catamenial pneumothorax is a rare complication secondary to pleural endometriosis. We present a case of a 37-year-old-female with a history of recurrent pneumothoraces with an associated temporal relationship to the onset of her menses. In addition to her recurrent pneumothoraces, on further evaluation, she was found to have multiple nodular masses within the omentum. A thoracoscopic biopsy was subsequently performed, which showed endometrial implants within the pleural space and within the omental cavity. The radiological features and pathogenesis of this rare disease are reviewed and discussed with reference to relevant literature.

Bochdalek Hernia With Obstructive Uropathy

Bochdalek hernias are postero-medial diaphragmatic defects that usually contain peritoneal fat and often remain asymptomatic. We present a unique case in which involvement of the adjacent ureter in the hernia defect resulted in obstructive uropathy.

Fibrous Skeleton of the Heart: Anatomic Overview and Evaluation of Pathologic Conditions with CT and MR Imaging

The fibrous skeleton is concentrated at the base of the ventricular mass. It provides electrical insulation at the atrioventricular level and fibrous continuity for the leaflets of the mitral, aortic, and tricuspid valves. Its components include the fibrous trigones, the fibrous area of aortic-mitral continuity, the subvalvar collar of the mitral valve, the membranous septum, the interleaflet triangles, the tendon of Todaro, and likely the conus ligament. The majority of the mitral annulus is fibrous, but the only true fibrous part of the tricuspid annulus is where the valvar leaflets are attached to the central fibrous body. At the aortic annulus, the fibrous elements support only the noncoronary aortic sinus and parts of the right and left coronary sinuses. The ring-shaped annulus of the arterioventricular valves as localized with imaging techniques (imaging annulus) differs from the crown-shaped hemodynamic annulus of the arterial valves. The imaging annulus corresponds to the plane passing through the nadirs of the hinge-lines of the leaflets. The hinges of the pulmonary valve are not part of the fibrous skeleton. Computed tomography (CT) and magnetic resonance (MR) imaging are excellent modalities for evaluation of the anatomy, physiologic variations, and pathologic conditions of the fibrous skeleton. The submillimeter isotropic three-dimensional datasets obtained with CT and the high contrast resolution of MR imaging are the main advantages of these modalities in assessing anatomy. The function of the valves and associated annuli can best be studied with MR imaging. Pathologic conditions involving the area, including paravalvar leaks, abscesses, perforation, and pseudoaneurysms, usually occur as a complication of infective endocarditis or extensive calcifications after valvar surgery. MR imaging and CT can demonstrate these lesions equally well. CT is the preferred technique for showing the extent of calcifications in the fibrous skeleton. Large calcifications involving the central fibrous body can cause heart block by interfering with the normal function of the His bundle and its branches. ©RSNA, 2017.

Computed Tomographic Diagnosis of Myocardial Fat Deposits in Sarcoidosis.

Objective Fat deposits in the left ventricle (LV) myocardium are uncommon and usually indicate scar due to chronic myocardial infarction. The purpose of this study was to determine the incidence of fatty lesions in the LV of patients with sarcoidosis. Materials and Methods Review of noncontrast computed tomographic images (2-mm thickness) in 133 patients with documented extracardiac sarcoidosis (age, 35–82 years, 55 ± 10 years, 67% female) with no history of significant coronary artery disease (clinical and coronary calcium) was performed. A control group included noncontrast computed tomographies with no coronary calcium in 133 patients with age/sex (59 ± 6 years, 73% female) similar to the sarcoid target group. Locations and morphology (linear vs bulky) of fat deposits (−30 to −180 Hounsfield units) and relevant intrathoracic findings were recorded. Results We found 35 fat deposits in 19 (14.3%) of sarcoid patients (target group: age, 59 ± 7 years, 78% female). Lesions were mainly at the LV apical level (n = 14). In the control group, 15 lesions in 13 (9.7%) patients were found. Numbers of fatty lesions in sarcoid targets were significantly higher than those in the control group (P = 0.015). The number of bulky lesions was significantly higher in sarcoid (n = 9) than in control (n = 1; P < 0.05). No significant difference was found for the rate of linear lesions. Interstitial lung disease was seen in 9 and enlarged lymph nodes in 9 of the sarcoid target group. There was no significant correlation between the severity of interstitial lung disease and the number of fatty lesions. Conclusions Sarcoid patients demonstrate a higher chance of having LV fat deposits with a characteristic bulky morphology.

Incremental value of color coding in 3D volume rendered CT images for interpretation of complex cardiothoracic vascular malformations

OBJECTIVES To evaluate the benefit of color coding of CT angiography images for the assessment of complex cardiovascular malformations by comparing the quality of 3D (dimensional) volume rendered (VR) images before and after vessel color coding. METHODS Cardiothoracic CT images of 34 patients with complex vascular malformations were retrospectively selected for post processing. 3D VR images were created without and after color coding of the target vessels. Source images as well as selected 3D VR images without and with color coding were reviewed independently by 4 observers and scores were recorded on a 4-point scale for overall image quality, visualization conspicuity of target vessels, and final interpretation of target structures. RESULTS Overall diagnostic advantages of color coded VR images compared with non-color coded VR images included; improved visualization of the anatomical course of vessels, improved visualization of the extent of abnormality, better understanding of the spatial relationship of structures (i.e. to right ventricle outflow tract), and improved overall quality of the images. For all comparisons the color coded score was statistically significantly better than the non-color coded score (p<0.0001). A trend showed that review speed was faster for color coded images (p=0.06). Good inter-observer agreement was achieved for the target conspicuity and final interpretation scores with weighted Kappa score of 0.66 (95% CI: 0.54, 0.79) and 0.71 (95% CI: 0.60, 0.81) respectively. CONCLUSION Color coded 3D VR images can optimize visualization of vascular structures and improve interpretation of complex vascular malformation in cardiothoracic CT studies.

Image Predictors of Treatment Outcome after Thoracic Aortic Dissection Repair

Treatment of thoracic aortic dissection remains highly challenging and is rapidly evolving. Common classifications of thoracic aortic dissection include the Stanford classification (types A and B) and the DeBakey classification (types I to III), as well as a new supplementary classification geared toward endovascular decision making. By using various imaging techniques, the extent of the dissection, the location of the primary intimal tear, the shape of the aortic arch, and the zonal involvement of the aortic arch-factors that affect the treatment strategy-can easily be identified. Thoracic endovascular aortic repair (TEVAR) is generally performed in two groups of patients: (a) those with a surgically repaired type A dissection, and (b) those with a complicated type B dissection. Several imaging findings can help predict the course of remodeling of the dissected aorta after a repaired type A dissection and TEVAR. A spectrum of imaging findings exist with regard to favorable (positive) or failing (negative) remodeling. A schematic model with imaging support allows the classification of important causes of failing remodeling into proximal and distal groups, on the basis of the origin of the refilling of the false lumen and the underlying pathophysiology of pressurization. Refilling of the false lumen of the aorta after repair of a type A dissection is usually secondary to a persistent intimal tear at the aortic arch, a leak of the distal graft anastomosis, or refilling from the false lumen of a dissected aortic arch vessel. After TEVAR, false lumen refilling is most commonly due to an incomplete seal of the proximal landing related to the aortic tortuosity, an arch branch stump, a supra-arch chimney stent, or the TEVAR technique. Online supplemental material is available for this article. ©RSNA, 2018.

Forward-Projected Model-Based Iterative Reconstruction in Screening Low-Dose Chest CT: Comparison With Adaptive Iterative Dose Reduction 3D

OBJECTIVE The objective of this study is to compare forward-projected model-based iterative reconstruction solution (FIRST), a newer fully iterative CT reconstruction method, with adaptive iterative dose reduction 3D (AIDR 3D) in low-dose screening CT for lung cancer. Differences in image noise, image quality, and pulmonary nodule detection, size, and characterization were specifically evaluated. MATERIALS AND METHODS Low-dose chest CT images obtained for 50 consecutive patients between December 2015 and January 2016 were retrospectively reviewed. Images were reconstructed using FIRST and AIDR 3D for both lung and soft-tissue reconstruction. Images were independently reviewed to assess image noise, subjective image quality (with use of a 5-point Likert scale, with 1 denoting far superior image quality; 2, superior quality; 3, equivalent quality; 4, inferior quality; and 5, far inferior quality), pulmonary nodule count, size of the largest pulmonary nodule, and characterization of the largest pulmonary nodule (i.e., solid, part solid, or ground glass). RESULTS Across all 50 cases, measured image noise was lower with FIRST than with AIDR 3D (lung window, 44% reduction, 41 ± 7 vs 74 ± 8 HU, respectively; soft-tissue window, 32% reduction, 11 ± 2 vs 16 ± 2 HU, respectively). Readers subjectively rated images obtained with FIRST as comparable to images obtained with AIDR 3D (mean [± SD] Likert score for FIRST vs AIDR 3D, 3.2 ± 0.3 for soft-tissue reconstructions and 3.0 ± 0.3 for lung reconstructions). For each reader, very good agreement regarding nodule count was noted between FIRST and AIDR 3D (interclass correlation coefficient [ICC], 0.83 for reader 1 and 0.78 for reader 2). Excellent agreement regarding nodule size (ICC, 0.99 for reader 1 and 0.99 for reader 2) and characterization of the largest nodule (kappa value, 0.92 for reader 1 and 0.82 for reader 2) also existed. CONCLUSION Images reconstructed with FIRST are superior to those reconstructed AIDR 3D with regard to image noise and are equivalent with regard to subjective image quality, pulmonary nodule count, and nodule characterization.

Diaphragm Appearance: A Clue to the Diagnosis of Pulmonary and Extrapulmonary Pathology

The diaphragm is often overlooked or incompletely evaluated when interpreting chest radiographs. Alterations in the appearance of the diaphragm on chest radiographs such as elevation, contour abnormalities, adjacent lucency, and calcifications can offer clues to pulmonary and extrapulmonary pathology. Familiarity with common causes of these alterations facilitates the appropriate selection of additional imaging and leads to the diagnosis of both benign and life-threatening processes. This article reviews normal variations in the appearance of the diaphragm as well as those associated with pulmonary and extrapulmonary pathology.