Abdominal Wall Thickness at Palmer's Point and Distance to Adjacent Structures across the Body Mass Index Spectrum.

STUDY OBJECTIVE: Studies delineating left upper quadrant (LUQ) anatomy across a range of body mass indices are lacking. We aimed primarily to compare, between nonobese and obese women, abdominal wall thickness and the distance from the LUQ to key structures. In addition, we aimed to characterize LUQ anatomy in underweight women. DESIGN: A retrospective cohort study. SETTING: A tertiary academic medical institution. PATIENTS: Sixty women (30 nonobese, 30 obese) aged 18 years and older who underwent abdominal imaging from October 1, 2018, to December 31, 2018. INTERVENTIONS: Computed tomography imaging of the chest, abdomen, and pelvis. MEASUREMENTS AND MAIN RESULTS: Abdominal wall thickness at the LUQ was significantly greater in obese (4.3 ± 1.7 cm) than nonobese patients (2.4 ± 1.7 cm) (p <.001), as were distances to all key structures (aorta, vena cava, spleen, stomach, pancreas, liver, left kidney, and pelvis) (p ≤.02). On average, all structures, with the exception of stomach and liver, were >10 cm (the length of a typical insufflation needle) away from the LUQ insertion point in obese women. In underweight women, the aorta, spleen, stomach, pancreas, and liver were all within 10 cm of the LUQ insertion point. Within the obese and nonobese group, abdominal wall thickness at the LUQ was significantly greater than at the umbilicus (p <.001). Body mass index was more strongly correlated with abdominal wall thickness at the LUQ (r = 0.84; p <.001) than at the umbilicus (r = 0.69; p <.001) (p = .007 for comparison). CONCLUSION: This study highlights special anatomic considerations for LUQ access in obese and underweight patients. In obese women, abdominal wall thickness may be greater at this site than at the umbilicus and the liver and stomach remain within reach of an insufflation needle. The increased working distance from the LUQ to the pelvis in obese patients may necessitate specialized instruments if this site is used during surgery. In underweight women, the aorta, in addition to many other structures, is within reach of commonly used entry devices.

Brain Glucose Hypometabolism and Iron Accumulation in Different Brain Regions in Alzheimer's and Parkinson's Diseases.

The aim of this study was to examine the relationship between the presence of glucose hypometabolism (GHM) and brain iron accumulation (BIA), two potential pathological mechanisms in neurodegenerative disease, in different regions of the brain in people with late-onset Alzheimer's disease (AD) or Parkinson's disease (PD). Studies that conducted fluorodeoxyglucose positron emission tomography (FDG-PET) to map GHM or quantitative susceptibility mapping-magnetic resonance imaging (QSM-MRI) to map BIA in the brains of patients with AD or PD were reviewed. Regions of the brain where GHM or BIA were reported in each disease were compared. In AD, both GHM and BIA were reported in the hippocampus, temporal, and parietal lobes. GHM alone was reported in the cingulate gyrus, precuneus and occipital lobe. BIA alone was reported in the caudate nucleus, putamen and globus pallidus. In PD, both GHM and BIA were reported in thalamus, globus pallidus, putamen, hippocampus, and temporal and frontal lobes. GHM alone was reported in cingulate gyrus, caudate nucleus, cerebellum, and parietal and occipital lobes. BIA alone was reported in the substantia nigra and red nucleus. GHM and BIA are observed independent of one another in various brain regions in both AD and PD. This suggests that GHM is not always necessary or sufficient to cause BIA and vice versa. Hypothesis-driven FDG-PET and QSM-MRI imaging studies, where both are conducted on individuals with AD or PD, are needed to confirm or disprove the observations presented here about the potential relationship or lack thereof between GHM and BIA in AD and PD.