Posterior trans-mediastinal lung herniation in a postoperative Marfan's patient.

Thoracic hernias are defined as the protrusion of contents either into or outside of the thoracic cavity. These hernias can be acquired or congenital and occur in varying locations. Acquired thoracic hernias typically develop after surgery or trauma. The most common form is intercostal herniation due to thoracotomy. Trans-mediastinal herniation of the lung is even less common, typically seen in patients with sequestration, scimitar syndrome, or pneumonectomy, and, when present, commonly occurs across the anterior mediastinum. Here, we present to our knowledge the first known case of posterior trans-mediastinal lung herniation diagnosed on CT after thoracoabdominal aneurysm repair in a patient with Marfan's disease, highlighting the importance of evaluating for rare anatomic complications in the post-operative setting. (1).

Patency of vein graft anastomoses facilitated with the hexalon device.

PURPOSE: The Hexalon system (Castlewood Surgical, Inc, Dallas, TX) is a new device that facilitates a clampless, hand-sutured, vein-to-aorta anastomoses in no-touch off-pump coronary artery bypass surgery. Hexalon-facilitated anastomoses are structurally equivalent to traditional sutured anastomoses, but can be placed during off-pump coronary artery bypass surgery. It follows that these facilitated anastomoses would show similar patency rates to traditional sutured anastomoses. This is the first published data validating mid-term patency of Hexalon-facilitated anastomoses. DESCRIPTION: Evaluation of bypass grafts by cardiac computed tomography angiography is highly accurate and has increasingly been used to assess graft patency in anastomotic device feasibility trials. We studied 15 proximal Hexalon-facilitated anastomoses for patency in 10 patients at least 6 months after off-pump coronary bypass surgery using gated cardiac computed tomography angiography. EVALUATION: All 15 facilitated anastomoses were patent. All 10 CT studies were of sufficient quality for accurate interpretation. CONCLUSIONS: The Hexalon system is a new and potentially valuable tool in advancing off-pump coronary artery bypass surgery.

A computed tomography scan assessment of synthetic multiphase polymer scaffolds used for osteochondral defect repair.

PURPOSE: To evaluate the radiographic response of a synthetic multiphase implant at various intervals after implantation and assess the nature of bone ingrowth into the implant location. METHODS: Patients undergoing autologous osteochondral transplantation for full-thickness condylar defects with the donor sites filled by use of a synthetic implant were evaluated by computed tomography (CT) scan for the density at both donor and recipient sites. Hounsfield unit (HU) readings were obtained at the synthetic implant, transplanted autograft plug, soft-tissue, cancellous bone, and cortical bone sites. The implant site material was graded by an established ossification quality score (range, 1 to 4). RESULTS: Nine patients underwent CT scans at intervals ranging from 2 to 63 months after surgery. This sequence of images tracked the potential development of bone ingrowth activity. Postoperative imaging confirmed complete autograft bone plug healing. The synthetic implant site CT scans showed a drop in density from 84 HU at 4 months to 19 HU by 13 months (fibrous scar density). The ossification quality score for all synthetic implants was 1 (tract filled with soft-tissue density) instead of 4 (cancellous bone). The transplanted autograft plug densities were consistent with and completely incorporated into the adjacent cancellous bone. CONCLUSIONS: The synthetic multiphase implant showed no evidence of bone ingrowth, osteoconductivity, or ossification. The implant density declined over time to that of fibrous scar. This synthetic plug does not provide subchondral structural support for any tissue that grows over it. This study does not support the use of this implant for the primary repair of articular cartilage lesions. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Long-term absorption of beta-tricalcium phosphate poly-L-lactic acid interference screws.

PURPOSE: The purpose of this study was to evaluate the long-term in vivo degradation of biodegradable interference screws made of poly-L-lactic acid (PLLA) and beta-tricalcium phosphate (beta-TCP). METHODS: Twenty patients undergoing patellar tendon autograft anterior cruciate ligament reconstruction fixed at both the femur and tibia with beta-TCP-PLLA screws at least 44 months earlier were evaluated by physical, radiographic, and computed tomography (CT) evaluations. This study was approved by the institutional review board. Lysholm, Tegner, Cincinnati, and International Knee Documentation Committee scores were also obtained. CT data were measured in Hounsfield units. RESULTS: We evaluated 13 male and 7 female patients at a mean of 50 months after surgery (range, 44 to 56 months). CT scans and radiographs showed the bone plug fused to the tunnel wall with no beta-TCP-PLLA screw remaining. The screws were replaced with clearly calcified non-trabecular material, denser than soft tissue. Osteoconductivity was present in 75% of the tunnels and complete in 10%. No positive pivot-shift tests were found. Lysholm, Tegner, and Cincinnati scores improved from 60.4, 3.7, and 53.3, respectively, preoperatively to 90.8, 5.8, and 86.4, respectively, at follow-up. The mean side-to-side difference determined by use of the KT arthrometer (MEDmetric, San Diego, CA) was 0.4 mm. CONCLUSIONS: The beta-TCP-PLLA interference screw (Bilok; ArthroCare, Sunnyvale, CA) completely degraded, and no remnant was present 4 years after insertion. Osteoconductivity was confirmed by CT scans at 75% of the screw sites and completely filled the site in 10%. The addition of beta-TCP to PLLA results in a biocomposite interference screw that is osteoconductive. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Measurement of right ventricular volumes before and after atrial septal defect closure using multislice computed tomography.

Volumetric measurements of the right ventricle are helpful in patients with atrial septal defects (ASDs) in estimating the degree of right ventricular (RV) failure. They also may be important in following patients postoperatively after ASD closure. Traditional imaging modalities used to obtain such measurements have had limitations in measuring the complex shape of the right ventricle. Multislice computed tomography (MSCT) is a technique that provides excellent spatial resolution of the moving heart. This study was conducted to assess whether MSCT could be used to evaluate RV end-diastolic volume (EDV) before and after the closure of an ASD. From June 2004 to March 2006, 10 patients with ASDs underwent MSCT to calculate their RV volumes. The patients then had their ASDs closed by either a percutaneous or a surgical approach. Three months later, the patients' MSCT scans were repeated, and RV volumes were recalculated. EDV was approximated using 3-dimensional volume-rendered models of the right ventricle. At a mean follow-up of 3 months, a significant reduction in mean RV EDV, indexed for body surface area, was demonstrated, from 131 +/- 31 to 83 +/- 22 cm(3)/m(2) (p = 0.0007). In conclusion, this report is the first to describe the utility of MSCT to demonstrate RV EDV reduction after ASD closure.

Use of multislice computed tomographic coronary angiography for the diagnosis of anomalous coronary arteries.

The accurate diagnosis of anomalous coronary arteries by invasive angiography is limited by the inability to define the anatomic course in relation to surrounding structures. Computed tomographic coronary angiography has recently emerged as a noninvasive method to visualize the coronary arteries. Multislice computed tomography with up to 64 detector arrays, along with 3-dimensional rendering, has further improved the temporal and spatial resolution of noninvasive coronary imaging. In this series of cases, the investigators describe their institution's experience with computed tomographic coronary angiography as a complement to invasive coronary angiography in determining the origin and course of different anomalous coronary arteries in 16 patients. With the aid of 3-dimensional volume rendering, 6 anomalous right coronary arteries, 4 anomalous left circumflex coronary arteries, 4 single coronary arteries, and 2 anomalous left main coronary arteries were all clearly defined with regard to their origin and course. It is proposed that computed tomographic coronary angiography is the diagnostic test of choice in the evaluation of such anomalies.

Computed tomographic coronary angiography: experience at Baylor University Medical Center/Baylor Jack and Jane Hamilton Heart and Vascular Hospital.

Noninvasive cardiac computed tomographic imaging using multislice or electron beam technology has been shown to be highly specific and sensitive in diagnosing coronary heart disease. It is about a fifth of the cost of coronary angiography and is particularly well suited for evaluating patients with a low or low to moderate probability of having obstructive coronary atherosclerosis. In addition, it offers more information than calcium scoring: because of the intravenous contrast used, it temporarily increases the density of the lumen and allows differentiation of soft plaque from calcified plaque. The Baylor Hamilton Heart and Vascular Hospital now uses this modality to define coronary atherosclerosis in patients who would otherwise have needed invasive coronary angiography; several research protocols with the technique are also under way. Baylor has recently upgraded to the 64-slice scanner. It is expected that computed tomographic coronary angiography will replace a significant percentage of invasive cardiac catheterizations.

Pseudohypocalcemia after magnetic resonance imaging with gadolinium in patients with cirrhosis.

Hypocalcemia in patients with cirrhosis may be due to a number of causes. We noted a relationship between injection with gadodiamide, a particular gadolinium chelate, during magnetic resonance imaging of the liver and the development of a falsely low serum total calcium level in a patient with cirrhosis. A cross-reference and retrospective chart review identified 10 additional patients in whom this phenomenon was noted. We describe the temporal relationship and clinical characteristics of these patients. Pseudohypocalcemia following magnetic resonance imaging with gadodiamide contrast should be considered in the differential diagnosis of hypocalcemia in patients with cirrhosis.