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Radiologists will be at the center of the rapid technologic expansion of three-dimensional (3D) printing of medical models, as accurate models depend on well-planned, high-quality imaging studies. This article outlines the available technology and the processes necessary to create 3D models from the radiologist's perspective. We review the published medical literature regarding the use of 3D models in various surgical practices and share our experience in creating a hospital-based three-dimensional printing laboratory to aid in the planning of complex surgeries.

One-year outcomes following successful transseptal balloon-expandable transcatheter heart valve implantation in high-risk patients with degenerated mitral bioprostheses are excellent, characterized by durable symptom relief and prosthesis function. Although mitral valve in ring and valve in MAC have higher operative morbidity and mortality, 1-year outcomes after an initially successful procedure are favorable in carefully selected patients.

Florfenicol, a veterinary fluorinated analog of thiamphenicol, is approved for treatment of bovine respiratory pathogens in the United States. However, florfenicol resistance has recently emerged among veterinary Escherichia coli isolates incriminated in bovine diarrhea. The flo gene, which confers resistance to florfenicol and chloramphenicol, has previously been identified inPhotobacterium piscicida and Salmonella enterica serovar Typhimurium DT104. The flo gene product is closely related to the CmlA protein identified inPseudomonas aeruginosa. The cmlA gene confers nonenzymatic chloramphenicol resistance via an efflux mechanism. Forty-eight E. coli isolates recovered from calves with diarrhea, including 41 that were both chloramphenicol and florfenicol resistant, were assayed for the presence of both flo andcmlA genes. Forty-two of the 44 isolates for which florfenicol MICs were ≥16 μg/ml were positive via PCR for theflo gene. All E. coli isolates for which florfenicol MICs were ≤8 μg/ml were negative for the flogene (n = 4). Twelve E. coli isolates were positive for cmlA, and chloramphenicol MICs for all 12 were ≥32 μg/ml. Additionally, eight isolates were positive for bothflo and cmlA, and both florfenicol and chloramphenicol MICs for these isolates were ≥64 μg/ml. DNA sequence analysis of the E. coli flo gene demonstrated 98% identity to the published GenBank sequences of both serovar TyphimuriumfloSt and P. piscicida pp-flo. Theflo gene was identified on high-molecular-weight plasmids of approximately 225 kb among the majority of florfenicol-resistantE. coli isolates. However, not all of the florfenicol-resistant E. coli isolates tested contained the large flo-positive plasmids. This suggests that several of the E. coli isolates may possess a chromosomalflo gene. The E. coli flo gene specifies nonenzymatic cross-resistance to both florfenicol and chloramphenicol, and its presence among bovine E. coli isolates of diverse genetic backgrounds indicates a distribution much wider than previously thought.

Prognosis and therapeutic decisions are often based on left ventricular ejection fraction (LVEF), which means the LVEF needs to be accurately measured. Many imaging modalities can measure LVEF. Each of these modalities is subject to measurement errors that can lead to the inaccurate calculation of LVEF. This article reviews the most common non-invasive imaging modalities – i.e., echocardiography, magnetic resonance imaging (MRI), computed tomography (CT), radionuclide angiography, gated myocardial perfusion single-photon emission computed tomography (SPECT) and gated myocardial perfusion positron emission tomography (PET) – used to measure LVEF, as well as the common sources of error with each of them. It is important to understand these sources of errors in order to prevent them, and recognise them when they do occur so that they can be corrected if possible.