Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.
Example: Abstract: Some patients converted from ventricular fibrillation to organized rhythms by defibrillation-trained ambulance technicians (EMT-Ds) will refibrillate before hospital arrival. The authors analyzed 271 cases of ventricular fibrillation managed by EMT-Ds working without paramedic back-up. Of 111 patients initially converted to organized rhythms, 19 (17%) refibrillated, 11 (58%) of whom were reconverted to perfusing rhythms, including nine of 11 (82%) who had spontaneous pulses prior to refibrillation. Among patients initially converted to organized rhythms, hospital admission rates were lower for patients who refibrillated than for patients who did not(53% versus 76%, P = NS), although discharge rates were virtually identical (37% and 35%, respectively). Scene-to-hospital transport times were not predictively associated with either the frequency of refibrillation or patient outcome. Defibrillation-trained EMTs can effectively manage refibrillation with additional shocks and are not at a significant disadvantage when paramedic back-up is not available.
Example solution: Refibrillation managed by EMT-Ds
Example explanation: The abstract is about refibrillation and it is also mentioned in the abstract that it is managed by EMT-Ds. So it is an apt title.

Problem: Abstract: Digital subtraction angiography is a new imaging technique that uses a computer to subtract background distractions and to enhance contrast and density. The intravenous administration of contrast material permits safe outpatient screening for arterial disease. The exact role of intravenous digital subtraction angiography in cerebrovascular disease is still in evolution and remains the subject of debate. The value of intravenous digital subtraction angiography in screening for renovascular hypertension is less controversial, but selection of patients remains a subject for further study. Intra-arterial digital subtraction angiography has become a standard imaging technique that offers both the inherent safety produced by reduction of the volume of contrast material and the added safety afforded by reduction of both the size of the catheter and the time required to perform complex arterial interventional procedures. With the evolution of more sophisticated computed technology and radiographic equipment, the impact of both intravenous and arterial digital subtraction angiography will become even more dramatic.
Solution: Digital subtraction angiography.