Alexandra A. J. de Rotte

Objective To evaluate the detection of pituitary lesions at 7.0 T compared to 1.5 T MRI in 16 patients with clinically and biochemically proven Cushing’s disease. Methods In seven patients, no lesion was detected on the initial 1.5 T MRI, and in nine patients it was uncertain whether there was a lesion. Firstly, two readers assessed both 1.5 T and 7.0 T MRI examinations unpaired in a random order for the presence of lesions. Consensus reading with a third neuroradiologist was used to define final lesions in all MRIs. Secondly, surgical outcome was evaluated. A comparison was made between the lesions visualized with MRI and the lesions found during surgery in 9/16 patients. Results The interobserver agreement for lesion detection was good at 1.5 T MRI (κ = 0.69) and 7.0 T MRI (κ = 0.62). In five patients, both the 1.5 T and 7.0 T MRI enabled visualization of a lesion on the correct side of the pituitary gland. In three patients, 7.0 T MRI detected a lesion on the correct side of the pituitary gland, while no lesion was visible at 1.5 T MRI. Conclusion The interobserver agreement of image assessment for 7.0 T MRI in patients with Cushing’s disease was good, and lesions were detected more accurately with 7.0 T MRI. Key Points • Interobserver agreement for lesion detection on 1.5 T MRI was good; • Interobserver agreement for lesion detection on 7.0 T MRI was good; • 7.0 T enabled confirmation of unclear lesions at 1.5 T; • 7.0 T enabled visualization of lesions not visible at 1.5 T.

In the current study, the presence of cerebral cortical microinfarcts (CMIs) was evaluated in a series of 21 patients with a symptomatic high-grade > 50% stenosis of the carotid artery. A T₂-weighted fluid-attenuated inversion recovery sequence and a T₁-weighted turbo field echo sequence of the brain were obtained at 7.0 Tesla magnetic resonance imaging. Primary study endpoint was the number of CMIs and macroinfarcts. In total, 53 cerebral infarcts (35 macroinfarcts; 18 CMIs) were found ipsilateral to the symptomatic carotid artery, in 14 patients (67%). In four of these patients, both CMIs and macroinfarcts were visible. In the contralateral hemisphere, seven infarcts (five macroinfarcts and two CMIs) were found in five patients (24%). In the ipsilateral hemispheres, the number of CMIs and macroinfarcts were significantly correlated ( P = 0.02). Unpaired comparison of medians showed that the number of CMIs in the ipsilateral hemisphere was significantly higher than the number of CMIs in the contralateral hemisphere ( P = 0.04). No significant correlation was found between stenosis grade and the number of any infarct. The current study shows that in symptomatic patients with significant extracranial carotid artery stenosis, CMIs are part of the total cerebrovascular burden and these CMIs prevail with a similar pattern as observed macroinfarcts.

Since the pituitary gland measures 3-8 mm, imaging with the highest possible spatial resolution is important for the detection of even smaller lesions such as those seen in Cushing's disease. In the current feasibility study, we tested a multi-sequence MRI protocol to visualize the pituitary gland in high resolution at 7.0 Tesla (7.0 T).