Impact of stress and hypertension on the cerebrovasculature.

OBJECTIVES: Both stress and hypertension (HTN) are considered major health problems that negatively impact the cerebral vasculature. In this article we summarize the possible relationship between stress and HTN. METHODS: We conducted a systematic review of the literature using a database search of MEDLINE, PubMed, Scopus, and Web of Science. RESULTS: Psychological stress is known to be an important risk factor for essential hypertension. Acute stress can induce transient elevations of blood pressure in the context of the fight-or-flight response. With increased intensity and duration of a perceived harmful event, the normal physiological response is altered, resulting in a failure to return to the resting levels. These changes are responsible for the development of HTN. Genetic and behavioral factors are also very important for the pathogenesis of hypertension under chronic stress situation. In addition, HTN and chronic stress may lead to impaired auto-regulation, regional vascular remodeling, and breakdown of the blood brain barrier (BBB). The effects of both HTN and chronic stress on the cerebral blood vessels shows that both have common structural and functional effects including endothelial damage with subsequent increased wall thickness, vessel resistance, stiffness, arterial atherosclerosis, and altered hemodynamics. CONCLUSION: Most of the above mentioned vascular effects of stress were primarily reported in animal models. Further in-vivo standardization of pathological vascular indices and imaging modalities is warranted. Radiological quantification of these cerebrovascular changes is therefore essential for in depth understanding of the healthy and diseased cerebral arteries functions, identification and stratification of patients at risk of cardiovascular and neurological adverse events, enactment of preventive measures prior to the onset of systemic HTN, and the initiation of personalized medical management.

Correction to: CT angiograms of the neck in strangulation victims: incidence of positive findings at a level one trauma center over a 7-year period.

The original source of the flowchart in Fig. 3 has not been referenced and acknowledged correctly in the original article. This is now corrected.

An unusual vermiform giant arachnoid granulation.

Arachnoid granulations are outpouchings of arachnoid membrane which extend into the dural sinuses or calvarium, surrounded by a capsule of dense connective tissue. Within dural sinuses, these appear as well-defined, nodular, rounded, or ovoid structures of focal localization. However, it is important to be aware of their variability in presentation in order to correctly identify them and distinguish them from other dural sinus pathology, especially a misdiagnosis of venous sinus thrombosis with risks of unnecessary anticoagulation, intravascular thrombolysis/thrombectomy, or invasive intracranial pressure monitoring. Here we demonstrate a case of a previously unreported giant intrasinus arachnoid granulation of an unusual vermiform morphology, unduly elongated up to 6 cm in length, involving a significant segment of the superior sagittal sinus. The proof of this diagnosis was the radiologic appearance on multiple modalities and an unchanged appearance over the long-term.

CT angiograms of the neck in strangulation victims: incidence of positive findings at a level one trauma center over a 7-year period.

PURPOSE: To determine the incidence of acute findings diagnosed with computed tomography angiography (CTA) of the neck among emergency department patients presenting with strangulation injury. METHOD AND MATERIALS: This institutional review board-approved, HIPAA-compliant retrospective review was performed at our academic urban level 1 trauma center. The PACS database was queried for all consecutive patients who had CTAs of the neck performed for the exam indication of strangulation between January 1, 2009, and April 30, 2016, resulting in 142 included patients. Analysis of the individual cases was then performed, recording any positive results, with clinical findings classified using, when possible, standardized terminology found in the literature. Frequency of acute injury in the CTA neck examinations was determined with the calculation of 95% confidence interval (CI) and positive clinical findings were evaluated by calculation of prevalence. Additionally, two board certified radiologists with training in neuroradiology assessed the cases for vascular injury. RESULTS: There were 142 patients who met inclusion criteria (average age, 32.6 years) and 116 (81.7%) patients were female. CTA of the neck revealed 21 patients to have acute injuries (15.5%, 95% CI 9.5, 21.4) including 6 initially reported vascular injuries (4.2%, 95% CI 0.9, 7.5). Although neck pain (73, 51.4%), loss of consciousness (67, 47.2%), and headache (31, 21.8%) were frequently reported in the ROS, their predictive value of vascular injury was weak (4.1%, 4.5%, and 3.2%, respectively). On physical exam, redness/bruising of the neck (73, 51.4%) and neck tenderness (47, 33.1%) were both the most common and had the highest prevalence (19.2% and 12.8%, respectively), however, when selecting for vascular injuries alone were found to have low predictive yield (vascular injury 4.1% and 2.1%, respectively). The above statistics were based on the initial radiologist report and Emergency Department findings. After retrospective review, 3 Grade 1 BIFFL vascular injuries were identified (2.1%), with one false negative case (0.7%). CONCLUSION: Performing CTA of the neck after acute strangulation injury rarely identifies clinically significant findings, with vascular injuries proving exceedingly rare. As positive vascular injury could not be clinically predicted by history and physical examination, prospective validation of a clinical prediction rule in this population is warranted.

Anomalous Origin of the Anterior Choroidal Artery Proximal to an Ipsilateral Fetal Posterior Cerebral Artery: Case Report of an Extremely Rare Anatomic Variant and Discussion of its Clinical Implications.

The anterior choroidal artery (AChA) supplies important cerebral structures such as the internal capsule, optic tract, and lateral geniculate body. It is normally a branch of the communicating segment of the internal carotid artery (ICA) with significant neurological symptomatology if injured. Typically, the AChA originates distal to the posterior communicating artery (PCoA), but rare variants have previously been described. Such anatomical differences are particularly important entities, especially in the context of neuroendovascular procedures, as inadvertent damage to these arteries can have devastating consequences. In this case report, we present an unusual anatomical pattern of the right AChA arising proximal to an ipsilateral fetal PCA.

Clinico-radiologic factors in paraclinoid aneurysms associated with aneurysm rupture: A CTA study.

BACKGROUND AND PURPOSE: Paraclinoid aneurysms are commonly noted as incidental findings by computed tomography angiography (CTA), and there exists disagreement in the literature as to which patient and aneurysm characteristics predict subsequent rupture. This question is of particular significance given the complex anatomy of the paraclinoid region and the associated risks of aneurysm treatment. The purpose of this study was to determine significant associated risk factors for paraclinoid aneurysm rupture. MATERIALS AND METHODS: Medical records and CTA imaging from 179 patients with 205 paraclinoid aneurysms. Patient and aneurysm characteristics including aneurysm size, morphology, and multiplicity were gathered for analysis of rupture risk. Factors influencing the decision to treat or observe unruptured aneurysms were also evaluated. A Cox regression analysis was used, and results were corrected for multiple comparisons using the Bonferroni method. RESULTS: Aneurysm size, diameter:neck ratio, and multilobularity were significantly associated with increased rupture risk; however, only multilobularity remained significant after Bonferroni correction for multiple comparisons. Intervention for unruptured aneurysms was significantly more likely to occur among younger patients and multilobulated aneurysms, or those having a larger diameter, height, height:neck ratio, or diameter:neck ratio. CONCLUSIONS: Multilobularity constitutes a significant associated risk factor for rupture among paraclinoid aneurysms. Younger age, larger size and multilobulated aneurysms are characteristics that favored treatment over observation in this cohort.

Quantitative accuracy of PET/CT for image-based kinetic analysis.

Accuracy in quantification of activity concentrations (e.g., in Bq/ml) is essential for compartment modeling and kinetic analysis of dynamic reconstructed PET images. Dynamic PET data can be acquired in list-mode, and often are preferred over frame mode acquisitions due to the flexibility of reformatting the list-mode data into different dynamic image sequences after the acquisition is complete. However, most PET data are acquired as static frames. It therefore is important to evaluate the quantitative accuracy of list-mode or dynamic PET acquisitions prior to their use for clinical or research applications. The quantitative accuracy of list-mode acquisitions obtained with a Siemens Biograph 16 PET/CT scanner at our institution was evaluated; the image data were acquired from an anthropomorphic phantom (Data Spectrum, Hillsborough, NC) filled with an aqueous solution of 18F-fluorodeoxyglucose (FDG). PET data were acquired with the phantom for the following three different configurations: (1) with nonradioactive water in the body compartment and aqueous solution of 18F-FDG in only a fillable cylindrical insert to simulate the first several seconds of highly concentrated radioactivity within the field of view such as that in major venous or pulmonary vessels or in the cardiac ventricles, (2) with radioactivity throughout the entire body compartment and imaged with 3 min static frames and 12 min in list-mode that was reformatted into four 3-min frames, and (3) with radioactivity throughout the body compartment and imaged in list-mode and reformatted into sequential time frames having durations of 3, 10, 20, 30, 50, and 67 s, respectively (i.e., total of 180 s). All measured concentration values were compared against values acquired from static images or against the actual activity concentrations calculated from the calibrated activities dispensed into the phantom corrected for physical decay of 18F. These analyses demonstrated that the count rate limitation is minimal or negligible as long as there is no more than 370-440 MBq (10-12 mCi) activity entirely within the axial FOV and that list-mode acquisition yields accurate quantitation of activity concentrations over a clinically realistic range of activities. In addition, reformatting a single list-mode acquisition into frames of different durations retains quantitative accuracy with respect to static frame data and compared to the known radionuclide concentration in the phantom. Within these constraints, the list-mode data acquired with the Biograph 16 PET/CT system are quantitatively accurate for image-based kinetic analysis.

Intracoronary infusion of autologous mononuclear cells from bone marrow or granulocyte colony-stimulating factor-mobilized apheresis product may not improve remodelling, contractile function, perfusion, or infarct size in a swine model of large myocardial infarction.

AIMS: In a blinded, placebo-controlled study, we investigated whether intracoronary infusion of autologous mononuclear cells from granulocyte colony-stimulating factor (G-CSF)-mobilized apheresis product or bone marrow (BM) improved sensitive outcome measures in a swine model of large myocardial infarction (MI). METHODS AND RESULTS: Four days after left anterior descending (LAD) occlusion and reperfusion, cells from BM or apheresis product of saline- (placebo) or G-CSF-injected animals were infused into the LAD. Large infarcts were created: baseline ejection fraction (EF) by magnetic resonance imaging (MRI) of 35.3 +/- 8.5%, no difference between the placebo, G-CSF, and BM groups (P = 0.16 by ANOVA). At 6 weeks, EF fell to a similar degree in the placebo, G-CSF, and BM groups (-7.9 +/- 6.0, -8.5 +/- 8.8, and -10.9 +/- 7.6%, P = 0.78 by ANOVA). Left ventricular volumes and infarct size by MRI deteriorated similarly in all three groups. Quantitative positron emission tomography (PET) demonstrated significant decline in fluorodeoxyglucose uptake rate in the LAD territory at follow-up, with no histological, angiographic, or PET perfusion evidence of functional neovascularization. Immunofluorescence failed to demonstrate transdifferentiation of infused cells. CONCLUSION: Intracoronary infusion of mononuclear cells from either BM or G-CSF-mobilized apheresis product may not improve or limit deterioration in systolic function, adverse ventricular remodelling, infarct size, or perfusion in a swine model of large MI.

Glucose and insulin variations in patients during the time course of a FDG-PET study and implications for the "glucose-corrected" SUV.

INTRODUCTION: 2-Deoxy-2[(18)F]fluoro-d-glucose (FDG) positron emission tomography (PET) has an established role in the evaluation of cancer. Generally, tumor uptake and response to treatment are evaluated using the standardized uptake value (SUV). Some authors have proposed correcting SUV for glucose levels. Insulin is also thought to influence tumor uptake by changing uptake in other tissues. However, little attention has been paid to understanding the variability of glucose or insulin during a single PET study. METHOD: We studied the biological and instrumental variability of glucose and insulin measurements in 71 nondiabetic patients undergoing FDG-PET studies. Multiple glucose measurements were obtained in all 71 subjects, and in 69 of these 71 subjects, multiple serum insulin measurements were made. We determined the coefficient of observed variation (CV(ow)) and the coefficient of variation attributable to biological variability (CV(bv)) for both glucose and insulin. RESULTS: The mean glucose concentration was 78.9+/-13.5 mg/dl. The mean insulin value was 6.49+/-5.92 microU/ml. The weighted mean CV(ow) and CV(bv) was 5.0% and 3.6%, respectively, for glucose and 14.2% and 8.3%, respectively, for insulin. CONCLUSIONS: Variations in the range of 3.6% are observed in glucose measurements during the time course of an FDG scan even after accounting for analytical error; larger variations of 8.3% are observed in insulin levels. Therefore, corrections of SUV for blood glucose, especially if obtained from single measurements, can introduce additional errors of at least this much.

Correcting tumour SUV for enhanced bone marrow uptake: retrospective 18F-FDG PET/CT studies.

PURPOSE: The concentration of F-FDG in the bone marrow is usually low. One common cause of high uptake is due to bone marrow stimulating drugs administered in conjunction with chemotherapy or radiation therapy. It has been hypothesized that the sequestration of F-FDG to the bone marrow may reduce the standardized uptake value (SUV) of a tumour. We tested this hypothesis by quantifying total F-FDG uptake in the bone marrow of patients with visibly enhanced bone marrow uptake and computing its effect on tumour SUV. METHODS: Total F-FDG in bone marrow was measured in two groups of PET/CT studies: one (n=19) with visibly enhanced bone marrow, the other (n=5), a baseline group with 'normal' levels of uptake. To measure the F-FDG in bone marrow, the entire skeleton in the CT was segmented from surrounding tissue, and the resulting volume applied to the PET image. Using kinetic analysis we show that the predicted correction factor to tumour SUV is given by (1-q0/Q)/(1-q/Q), where Q is the injected dose, and q and q0 are enhanced and baseline bone marrow uptake (MBq). RESULTS: The enhanced bone marrow uptake averaged 8.9+/-3.2% of injected dose (15.2% max) vs. 4.2+/-0.4% (4.6% max) at baseline. This resulted in a predicted artificial decrease in tumour SUV of up to 11.5% (4.9+/-4.3%, on average). CONCLUSION: Enhanced bone marrow uptake is predicted to reduce tumour SUVs by as much as 11.5% in our patient group and is a potential confounding factor in using SUV for monitoring tumour response to therapy.

The effects of carbidopa on uptake of 6-18F-Fluoro-L-DOPA in PET of pheochromocytoma and extraadrenal abdominal paraganglioma.

UNLABELLED: 6-(18)F-fluoro-l-3,4-dihydroxyphenylalanine ((18)F-DOPA) PET is a useful tool for the detection of certain neuroendocrine tumors, especially with the preadministration of carbidopa, an inhibitor of DOPA decarboxylase. Whether carbidopa also improves (18)F-DOPA PET of adrenal pheochromocytomas and extraadrenal paragangliomas is unknown. The aim of this study was to investigate the sensitivity of (18)F-DOPA PET in the detection of paraganglioma and its metastatic lesions and to evaluate whether tracer uptake by the tumors is enhanced by carbidopa. METHODS: Two patients with nonmetastatic adrenal pheochromocytoma, and 9 patients with extraadrenal abdominal paraganglioma (1 nonmetastatic, 8 metastatic), underwent whole-body CT, MRI, baseline (18)F-DOPA PET, and (18)F-DOPA PET with oral preadministration of 200 mg of carbidopa. The dynamics of tracer uptake by these lesions and the physiologic distribution of (18)F-DOPA in normal tissues were recorded. RESULTS: Seventy-eight lesions were detected by CT or MRI, 54 by baseline (18)F-DOPA PET (P = 0.0022 vs. CT/MRI), and 57 by (18)F-DOPA PET plus carbidopa (P = 0.0075 vs. CT/MRI, not statistically significant vs. baseline). In reference to findings on CT and MRI, the sensitivities of baseline (18)F-DOPA PET were 47.4% for lesions and 55.6% for positive body regions, versus 50.0% (lesions) and 66.7% (regions) for (18)F-DOPA PET plus carbidopa (neither is statistically significant vs. baseline). Compared with baseline, carbidopa detected additional lesions in 3 (27%) of 11 patients. Carbidopa increased the mean (+/-SD) peak standardized uptake value in index tumor lesions from 6.4 +/- 3.9 to 9.1 +/- 5.6 (P = 0.037). Pancreatic physiologic (18)F-DOPA uptake, which may mask adrenal pheochromocytoma, is blocked by carbidopa. CONCLUSION: Carbidopa enhances the sensitivity of (18)F-DOPA PET for adrenal pheochromocytomas and extraadrenal abdominal paragangliomas by increasing the tumor-to-background ratio of tracer uptake. The sensitivity of (18)F-DOPA PET for metastases of paraganglioma appears to be limited.

Brown fat imaging with (18)F-6-fluorodopamine PET/CT, (18)F-FDG PET/CT, and (123)I-MIBG SPECT: a study of patients being evaluated for pheochromocytoma.

UNLABELLED: Several radiopharmaceuticals such as (18)F-FDG, (123)I-metaiodobenzylguanidine (MIBG), and (99m)Tc-tetrofosmin have demonstrated uptake in brown adipose tissue (BAT). It is important to recognize these normal variants so that they are not misinterpreted as a significant pathologic state. In addition, these radiopharmaceuticals may shed light on BAT physiology. (18)F-6-fluorodopamine (F-DA) is being used as a PET radiopharmaceutical to image adrenergic innervation and suspected pheochromocytoma. Past reports have suggested that BAT is increased in pheochromocytoma patients. METHODS: The images of 96 patients evaluated with (18)F-F-DA or (18)F-FDG PET/CT for known or suspected pheochromocytoma were reviewed retrospectively to determine whether localized uptake of a pattern typically associated with BAT was present. When available, contemporaneous images obtained using (123)I-MIBG were also reviewed for the presence of BAT. RESULTS: Of 67 patients imaged with (18)F-F-DA, BAT was found in 17.9%. Of 83 patients imaged with (18)F-FDG, 19.2% had BAT. Discordant findings related to uptake in BAT were often seen in patients studied with (18)F-FDG, (18)F-F-DA, or (123)I-MIBG. Overall, 26 (27.0%) of 96 patients showed BAT on at least 1 of the 3 imaging modalities. CONCLUSION: (18)F-F-DA can image BAT, most likely by localizing to sympathetic innervations in a manner similar to (123)I-MIBG. Patients with pheochromocytoma may have a greater BAT tissue mass or activation because of elevated levels of circulating catecholamines. Quantitative PET with (18)F-FDG and (18)F-F-DA may have a role in in vivo studies of BAT physiology in humans or animal models.

Reproducibility of regional left ventricular wall thickening obtained by gating resting and redistribution 201Tl myocardial SPECT studies.

BACKGROUND: We have assessed the reproducibility of the estimates of regional left ventricular wall thickening between resting and redistribution Tl gated single photon emission computed tomography (SPECT) studies. METHODS: Thirty patients (28 males, two females) aged between 38 and 72 years (57.0 +/- 8.4 years) underwent resting and redistribution Tl gated SPECT. Perfusion was assessed semi-quantitatively using scores of 0-4. The assessment of wall thickening was performed both visually and by using automated software using scores of 0-3. The assessment of reproducibility was performed in 20 individual segments and 37 pairs of contiguous segments in each patient. RESULTS: In resting studies, mean global left ventricular ejection fraction (LVEF), end diastolic volume and end systolic volume were 34.2 +/- 11.7%, 180.5 +/- 70.6 ml and 123.3 +/- 60.0 ml, respectively. The corresponding values for the redistribution studies were 32.7 +/- 10.1%, 179.7 +/- 70.6 ml and 125.5 + 63.0 ml, respectively. There was good correlation between the resting and redistribution LVEFs (r=0.88), end diastolic volumes (r=0.90) and end systolic volumes (r=0.933). Reproducibility of visual wall thickening was 66% in individual segments and 82% in pairs of contiguous segments, and that of automated wall thickening was 48.0% in individual segments and 68% in pairs of contiguous segments. CONCLUSION: In conclusion, global left ventricular functional parameters obtained by resting Tl gated SPECT studies are highly reproducible in patients with impaired resting left ventricular function and large areas of scarred myocardium. Wall thickening and wall motion data are more reproducible in contiguous segments than in individual segments.

Recurrent osteoid osteoma: a case report with imaging features.

We present a case of a 14-year-old boy, who presented with pain in the left thigh region for 1 year. The pain exacerbated at night, waking up the child and was relieved by salicylates. On the basis of clinical history, conventional radiography, computerized tomography and bone scintigraphy, a diagnosis of osteoid osteoma was made. The tumor was completely excised, and there was complete remission of symptoms. Six months following surgery, the pain recurred in the same region. Conventional radiography revealed dense sclerosis at the surgical site. Three-phase skeletal scintigraphy showed a focal area of increased blood pool activity followed by intense focal uptake in delayed images, characteristic of osteoid osteoma. Computerized tomography confirmed the findings of skeletal scintigraphy.

Hemoptysis demonstrated on Tc99m-sulfur colloid scanning: a rare complication of amoebic liver abscess.

We report the finding of bleeding into right lung from a ruptured amoebic liver abscess. A 25-year-old male presented with pain in the right lower chest and cough associated with expectoration of chocolate-colored sputum. Radiographs of chest showed right-sided pleural effusion. Serial images of Tc99m-sulfur colloid study revealed progressive accumulation of radiotracer in the upper photopenic area extending into the right lung region suggestive of active bleeding from the abscess cavity.