Death by Nondiagnosis: Why Emergent CT Angiography Should Not Be Done for Patients with Subarachnoid Hemorrhage

Abstract

musicians, and this increase correlated with the total duration of musical training. Although these changes may possibly be attributed to increased neuronal attenuation, increased NAA may also result from the increased size of neurons, alterations in synaptic attenuation, and changes in concentration of the other smaller metabolites under the NAA peak. In patients with impaired mathematic ability due to Gerstman syndrome or acalculia, spectroscopy demonstrated a focal decrease in NAA in the left posterior temporoparietal region, 8 indicating an alteration of neuronal attenuation or size. A decrease in creatine suggested impaired regional cellular energetics of the neurons or a decrease in glial cells. Diffusion-tensor imaging has also been used to evaluate brain changes resulting from learning tasks. In studies evaluating the effect of practicing piano on the brain, 9 a correlation was found between practicing and increased fiber tract organization. MR blood volume maps were also used to examine the effect of exercise on the brain. In a recent Proceedings of the National Academy of Science U S A publication, 10 exercise-induced neurogenesis was described and found to target the dentate gyrus, a subregion that is important for memory and implicated in cognitive aging.The exciting recent discovery that the brain can alter its shape and size during a period of weeks in response to the acquisition of new skills has led to valuable new insights on the structural response of the brain to learning and practice. New "functional" brain mapping techniques can now allow us to further evaluate morphologic brain changes in response to learning, development, disease, and recovery following injury. Future advances in imaging should also lead to a better understanding and use of the mechanisms underlying structural plasticity.

Coil Embolization of Very Small (2 mm or Smaller) Berry Aneurysms: Feasibility and Technical Issues

“…7 This is related to the lower resolution of CTA compared with DSA. 8 In our series, of the 3 cases in which CTA was performed, results were negative in 1 case, underlining the higher accuracy of 3DRA. 3DRA and DSA are of higher resolution than CTA and are better in the detection of aneurysms and in defining the morphologic features of the aneurysm.…”

“…The relationship with adjacent small vessels (as in Case 1) is also likely to be more accurately delineated by conventional angiography. Work-up of SAH with CTA versus conventional angiography is a frequently debated topic and, as pointed out by Kallmes et al, 8 CTA can result in false-negative results, and 3DRA probably remains the most accurate study in these patients. Van Rooij et al 9 have also reported that very small aneurysms can be commonly detected by 3DRA despite negative findings on DSA.…”

Multi-Detector Row CT Angiography with Direct Intra-Arterial Contrast Injection for the Evaluation of Neurovascular Disease: Technique, Applications, and Initial Experience

“…This prevents the dilution factor associated with IV-CTA, thus providing better bolus characteristics and, in turn, higher-quality imaging. 6 Intra-arterial CTA (IA-CTA) has previously been described by Nojiri et al 7 in describing the morphologic features of the artery of Adamkiewitz. Understanding the challenges of imaging small vascular lesions, we describe our technique of performing IA-CTA for the delineation of small cerebrovascular pathologic conditions as well as for treatment planning.…”

Use of CT Angiography and Digital Subtraction Angiography in Patients with Ruptured Cerebral Aneurysm: Evaluation of a Large Multihospital Data Base

“…[2][3][4][5] A recent meta-analysis concluded that CT angiography can be used as a primary examination tool in the diagnostic work-up of patients with SAH, 6 but that conclusion has been questioned because of weaknesses of CT angiography in the detection of small aneurysms and aneurysms adjacent to the skull base. [7][8][9] Whether the imaging method used is DSA or CT angiography, the imaging must identify the source of bleeding, most commonly an aneurysm. We evaluated a large, multihospital data base to determine how practice is evolving with regard to the use of CT angiography and DSA in patients with ruptured cerebral aneurysm.…”