Pulsatility Index in the Basal Ganglia Arteries Increases with Age in Elderly with and without Cerebral Small Vessel Disease

BACKGROUND AND PURPOSE

Cerebral small vessel disease contributes to stroke and cognitive impairment and interacts with Alzheimer disease pathology. Because of the small dimensions of the affected vessels, in vivo characterization of blood flow properties is challenging but important to unravel the underlying mechanisms of the disease.

MATERIALS AND METHODS

A 2D phase-contrast sequence at 7T MR imaging was used to assess blood flow velocity and the pulsatility index of the perforating basal ganglia arteries. We included patients with cerebral amyloid angiopathy (n = 8; identified through the modified Boston criteria), hypertensive arteriopathy (n = 12; identified through the presence of strictly deep or mixed cerebral microbleeds), and age- and sex-matched controls (n = 28; no cerebral microbleeds).

RESULTS

Older age was related to a greater pulsatility index, irrespective of cerebral small vessel disease. In hypertensive arteriopathy, there was an association between lower blood flow velocity of the basal ganglia and the presence of peri-basal ganglia WM hyperintensities.

CONCLUSIONS

Our results suggest that age might be the driving factor for altered cerebral small vessel hemodynamics. Furthermore, this study puts cerebral small vessel disease downstream pathologies in the basal ganglia region in relation to blood flow characteristics of the basal ganglia microvasculature.

Quantitative evaluation of prospective motion correction in healthy subjects at 7T MRI

PURPOSE

Quantitative assessment of prospective motion correction (PMC) capability at 7T MRI for compliant healthy subjects to improve high-resolution images in the absence of intentional motion.

METHODS

Twenty-one healthy subjects were imaged at 7 T. They were asked not to move, to consider only unintentional motion. An in-bore optical tracking system was used to monitor head motion and consequently update the imaging volume. For all subjects, high-resolution T₁ (3D-MPRAGE), T₂ (2D turbo spin echo), proton density (2D turbo spin echo), and T2∗ (2D gradient echo) weighted images were acquired with and without PMC. The images were evaluated through subjective and objective analysis.

RESULTS

Subjective evaluation overall has shown a statistically significant improvement (5.5%) in terms of image quality with PMC ON. In a separate evaluation of every contrast, three of the four contrasts (T₁ , T₂ , and proton density) have shown a statistically significant improvement (9.62%, 9.85%, and 9.26%), whereas the fourth one ( T2∗ ) has shown improvement, although not statistically significant. In the evaluation with objective metrics, average edge strength has shown an overall improvement of 6% with PMC ON, which was statistically significant; and gradient entropy has shown an overall improvement of 2%, which did not reach statistical significance.

CONCLUSION

Based on subjective assessment, PMC improved image quality in high-resolution images of healthy compliant subjects in the absence of intentional motion for all contrasts except T2∗ , in which no significant differences were observed. Quantitative metrics showed an overall trend for an improvement with PMC, but not all differences were significant.

Model-based iterative reconstruction for single-shot EPI at 7T

PURPOSE

To describe a model-based reconstruction strategy for single-shot echo planar imaging (EPI) that intrinsically accounts for k-space nonuniformity, Nyquist ghosting, and geometric distortions during rather than before or after image reconstruction.

METHODS

Ramp sampling and inhomogeneous B0 field-induced distortion cause the EPI samples to lie on a non-Cartesian grid, thus requiring the nonuniform fast Fourier transform. Additionally, a 2D Nyquist ghost phase correction without the need for extra navigator acquisition is included in the proposed reconstruction. Coil compression is also incorporated to reduce the computational load. The proposed method is applied to phantom and human brain MRI data.

RESULTS

The results demonstrate that Nyquist ghosting and geometric distortions are reduced by the proposed reconstruction. The proposed 2D phase correction is superior to a conventional 1D correction. The reductions of both artifacts lead to improved temporal signal-to-noise ratio (tSNR). The virtual coil results suggest that the processing time can be reduced by up to 75%, with a mean tSNR loss of only 3.2% when using 8-virtual instead of 32-physical coils for twofold undersampled data.

CONCLUSION

The proposed reconstruction improves the quality (ghosting, geometry, and tSNR) of EPI without requiring calibration data for Nyquist ghost correction. Magn Reson Med 78:2250-2264, 2017. © 2017 International Society for Magnetic Resonance in Medicine.

[Long-term course of chronic polyarthritis under basic drug therapy]

A retrospective analysis was undertaken of 31 patients with classical or proven chronic rheumatoid arthritis (CRA) who had been on a regimen of basic medication (gold salts, D-penicillamine, chloroquine, azathioprine--alone or in combination). Disease activity was checked by clinical, biochemical, immunological and radiological criteria. The laboratory results could not be altered by the basal medication and there was no relationship with the clinical and radiological findings, except for immunological results. None the less, the clinical symptoms improved under basal medication, even though the functional index got worse. The degree of joint destruction at the beginning and end of the observation period was markedly higher for seropositive than sero-negative cases, without significant differences in the rate of progression of joint destruction. Thus, definite long-term remission was achieved regarding the inflammatory changes but not the progressing joint destruction.

[Immunomodulating therapy in chronic polyarthritis with thymopentin. A multicenter placebo-controlled study of 119 patients]

In a multicenter, placebo-controlled and randomized double-blind trial 119 patients with rheumatoid arthritis were treated with thymopentin, an immunoregulating drug. The data of 107 patients were complete enough to be evaluated: 51 were given intravenous injections over ten minutes of 50 mg thymopentin three times weekly, 56 were similarly treated with a placebo solution. Significant improvement of five among nine clinical criteria were obtained with thymopentin after the third week of treatment. The response rate (improvement of a clinical parameter by at least 40%) was significantly greater for all clinical parameters in the thymopentin group. Regression to a functionally more favourable class (Steinbrocker's classification) occurred in seven thymopentin-treated, but in none of the placebo-treated patients. The improvement gradually subsided over four weeks after the end of treatment. There were no changes during the trial with respect to immunological, biochemical or haematological findings. Except for one systemic allergic reaction there were no side effects.

[Follow-up study in chronic polyarthritis as represented in roentgen image]

Thirty-one patients with chronic polyarthritis under medical treatment had x-rays of their hands performed at the beginning of the illness and after seven years, on average. The findings were compared with clinical and biochemical data. Despite treatment, there was marked progression in the periarticular destructive changes, although the clinical features had improved. The extent of periarticular destruction was significantly greater amongst seropositive than amongst seronegative patients, both at the beginning and the end of the study, but there was no significant difference in the rate at which this progressed. It was not possible to demonstrate a statistically significant correlation between the radiological appearance of the joints and the clinical and laboratory findings.

[Right atrial and ventricular thrombus formation in advanced left-side hypernephroma]

Hypernephromas may give rise to extensive thrombus formation in the inferior vena cava. In a 70-year-old female patient, two-dimensional echocardiography revealed a well-defined mass (2 X 2 cm in dimension) in the right atrium with occlusion of the tricuspid valve and thrombo-embolic material spreading from the inferior vena cava to the right atrium. This finding was confirmed by computed tomography and cavography. Computed tomography of the abdomen detected a large left-sided renal tumour and thrombotic occlusion of the whole vena cava. The patient was not willing to undergo surgery and the masses of thrombo-tumorous material in the right atrium and ventricle spread rapidly. Meanwhile a spontaneous recanalization of the oval foramen occurred. The patient died from massive pulmonary embolism. Only the signs and symptoms of right heart failure with confirmed thrombus formation in the right atrium led to the diagnosis of hypernephroma.

[Pulsed Doppler echocardiography in prosthetic aortic and mitral valve replacement]

In 94 subjects with normally functioning heart valve prostheses (51 aortic and 43 mitral valve prostheses) and in 35 patients with intact aortic and mitral valves, blood flow velocity within the heart and the aortic root have been recorded using pulsed Doppler velocity studies in patients with diseased valves of the left heart. In addition, a further 7 patients were investigated using invasive catheter tip velocitometry, pre- and postoperatively. The preversus postoperative changes of maximum velocity and acceleration is characterized as follows: postoperative flow velocity tracings show approximately normal profiles comparable to normal valve function. Turbulence formation is diminished and the steep uptroke of the normal flow pattern is restituted. Differences in transprosthetic blood flow patterns dependent on the implanted prosthesis model can be defined. Bioprostheses, in particular the Carpentier-Edwards device, reliably approximate normal amplitude-time characteristics. This is also true for the St. Jude Medical prosthesis with central flow properties. Velocitometric signs of valve dysfunction were detected in 9 patients: sensitivity was 100%; specificity ranged from 76% in aortic to 96% in mitral prostheses. Pulsed Doppler echocardiography therefore is a useful complement in the non-invasive haemodynamic tools and can be repeatedly applied to a patient with prosthetic cardiac valve replacement.

[Reduction of regurgitation in aortic and mitral insufficiency by captopril in acute and long-term trials]

Afterload reduction is an accepted therapeutic principle in the management of acute aortic (Ai) and mitral insufficiency (Mi). The question whether acute and chronic converting-enzyme inhibition by captopril has a beneficial hemodynamic effect in chronic Ai and Mi has been investigated in 17 patients with Ai and 10 with Mi. Ejection and regurgitation fraction (RF) were measured by radionuclide ventriculography (RNV) before, after 25 mg captopril and after 3-5 months of long-term treatment. The humoral response of the renin-angiotensin system (RAS) was quantified by analysis of angiotensin I and II. Captopril lowered under acute and chronic treatment RF in Ai and Mi by 32%. Angiotensin II levels decreased by the same order of magnitude. Acute and chronic vasodilation was followed by a distinct but well tolerated fall in blood pressure, especially in patients with Mi. These favourable hemodynamic effects of captopril make this therapy an adjunct but not an alternative to valve replacement.

Captopril mediated decrease of aortic regurgitation

The effect of captopril mediated afterload reduction on aortic regurgitation was investigated in 10 patients. Regurgitation was quantitated by means of the regurgitation fraction and the relation of regurgitant volume to end diastolic volume. These variables were derived from gated radionuclide ventriculography. After captopril treatment the blood concentration of angiotensin I rose whereas that of angiotensin II fell significantly. The conversion of angiotensin I to II was reduced to about 50% of the control value. Whereas blood pressure and heart rate did not change significantly, the regurgitation fraction and the regurgitant volume, normalised to end diastolic volume, were significantly reduced by captopril treatment. The ejection fraction remained essentially unchanged. These findings suggest that captopril reduces aortic regurgitation by reducing afterload.

[Reduction of regurgitation in aortic insufficiency by inhibition of the renin-angiotensin converting enzyme]

The effect of captopril-mediated afterload reduction on regurgitation was investigated in 10 patients with aortic insufficiency. Regurgitation was quantitated by the regurgitation fraction and the relation of regurgitant volume to enddiastolic volume, which were derived from gated radionuclide ventriculography. 19 patients with coronary artery disease and no evidence of valvular heart disease served as controls. In patients with coronary artery disease no significant regurgitation was found. In patients with aortic regurgitation the blood concentration of angiotensin I increased whereas that of angiotensin II decreased significantly after captopril-medication; thus, the conversion of angiotensin I to II was reduced to about 50% of the control value. Whereas blood pressure and heart rate did not change significantly, the regurgitation fraction and the normalized regurgitant volume were significantly reduced. The ejection fraction remained essentially unchanged. These findings suggest a favorable influence of captopril-induced afterload reduction on hemodynamics in aortic regurgitation.

[Pulsed Doppler echocardiography in aortic valve disease]

The diagnostic value of pulsed Doppler echocardiography (PDE) had not been sufficiently assessed up until now. Invasive catheter velocitometric measurements in the central vessels give quantitative information on the blood movement across the aortic and pulmonary valves. It is particularly useful in the quantification of aortic regurgitation. We successfully investigated 52 patients by means of PDE (ATL 500 A); 20 were suffering pure aortic incompetence, 11 pure stenosis and 21 had combined stenosis and regurgitation. Fifteen patients without aortic valvular disease served as controls. Our findings were compared with the results of cardiac catheterization and angiography in each case. In addition, 14 patients with aortic regurgitation were studied invasively by catheter velocitometry. The obtained regurgitation values were compared to the PDE method. In the PDE the underlying criteria for the assessment of the recordings were as follows: formal analysis of the analog signal and of the turbulence content during systole and diastole; in the flow velocity tracings aortic incompetence showed a steep increase with high peak to peak aortic velocities and scant turbulence formation; the reverse flow during regurgitation was accompanied by a high grade turbulent velocity pattern. The area under the diastolic (regurgitant) flow velocity curve (the time-amplitude integral) corresponded significantly with the angiographic severity of aortic insufficiency (r = 0.87). In aortic stenosis, turbulence formation leads to an approximately flat velocity profile across the ascending aorta, if the region in the vicinity of the valve is omitted. The flow velocity analog signals are considerably disturbed. However, the turbulence content which can be qualitatively estimated from the recordings, correlates well with the calculated valve area. In combined aortic valve stenosis and incompetence, the prevailing turbulent pattern does not always permit one to assess sufficiently the severity of the stenotic component, whereas the grade of incompetence can be, in general, evaluated. PDE complements the existing non-invasive techniques and probably essentially enriches non-invasive diagnostics.

Reduktion der Regurgitation bei Aorteninsuffizienz durch Hemmung des Renin-Angiotensin-Konversionsenzyms

Bei 10 Patienten mit Aorteninsuffizienz wurde der Einfluß der Nachlastsenkung durch Captopril-induzierte Hemmung des Angiotensin-Konversionsenzyms auf die Regurgitation untersucht. Als Maß für die Regurgitation diente die Regurgitationsfraktion und das Verhältnis des regurgitierten Volumens zum enddiastolischen Volumen; diese Parameter wurden mit Hilfe der Radionuklid-Ventrikulographie ermittelt. 19 Patienten mit koronarer Herzerkrankung ohne Herzklappenerkrankung dienten als Kontrollen. Bei Patienten ohne Klappenvitium wurde keine signifikante Regurgitation festgestellt. Bei Patienten mit Aorteninsuffizienz bewirkte Captopril eine signifikante Zunahme der Angiotensin I- und Abnahme der Angiotensin II-Konzentration im Blut; die daraus errechnete Konversionsrate von Angiotensin I und II nahm um 50% ab. Blutdruck und Pulsfrequenz wurden durch Captopril nicht signifikant beeinflußt. Im Gegensatz dazu fand sich eine signifikante Abnahme der Regurgitationsfraktion und des auf das enddiastolische Volumen normierten Regurgitationsvolumens; die Auswurffraktion wurde durch Captopril nicht signifikant verändert. Diese Befunde weisen auf eine Ökonomisierung der Herzarbeit bei Aorteninsuffizienz durch Captopril-induzierte Nachlast-Senkung hin.

[Clinical aspect and noninvasive diagnosis of cardiac myxomas]

The alteration of cardiac function in the presence of intracardiac tumors varies considerably according to their localization, size, and mode of insertion. Various cardiovascular diseases can be mimicked, e.g., primary valve dysfunction, cardiomyopathy, intracardiac shunts. Embolic events are frequent secondary symptoms. However, subtle noninvasive techniques such as M-mode and sector echocardiography, pulsed Doppler echocardiography, digital video subtraction angiography (DVSA), and computed tomography permit a thorough diagnosis of intracardiac tumorous masses without heart catheterization and catheter angiography. In this paper, myxomas within the left atrium (LA) and the right ventricle (RV) are described. Leading symptoms were systemic embolism and mitral stenosis (LA localization), low cardiac output and right to left shunt (RV localization). First suspicion of intracardiac tumor was raised by M-mode and sector echocardiography, whereas the diagnosis of LA myxoma was in one case missed by computed tomography and the RV myxoma was missed by right ventricular catheterization. In that case, only the four-chamber subxiphoidal sector echogram substantiated the diagnosis and explained the hemodynamic constellation of very low pulmonary pressures combined with right to left shunt. By the new technique of DVSA, all three tumors were plainly visualized. Nevertheless, echocardiography proved to be the most reliable technique of detecting intracardiac tumors.

[Pulsed Doppler-echocardiographic study of mitral valve dysfunction]

67 patients (pts)--20 with intact cardiac valve function, 15 with pure mitral stenosis, 20 with both mitral valve insufficiency and stenosis, 12 pts with pure mitral incompetence - have been investigated by non-invasive pulsed Doppler-echocardiography (PDE) previous to invasive right and left heart catheterization. The following criteria for evaluation of the PDE registrations are adopted: 1) Time-related correlation of ECG and flow velocity. 2) Formal analysis of the flow-velocity tracings. 3) Turbulence formation. 4) Maximum duration of flow. In pure mitral insufficiency, systolic turbulence formation is detected within the left atrium, which is present according to the severity only locally or throughout the entire left atrium. We calculated a specificity for the diagnosis of mitral incompetence of 94% and a sensitivity of 78%. In mitral stenosis a severity-dependent ventricular inflow velocity is prevalent - with an insidious onset until a dome-like or saw-tooth-like profile. Grading for severity of mitral stenosis can be performed as follows: the time from onset to maximum flow velocity of the diastolic inflows is measured and related to the time period of the cardiac cycle. A specificity of PDE for mitral stenosis of 88% and a sensitivity of 91% have been found. PDE is also being applied for assessment of hemodynamic efficacy of prosthetic mitral-valve replacement. In the evaluation of mitral valve dysfunction, PDE as a non-invasive technique is of high specificity and sensitivity as compared with the hemodynamic results of invasive procedures.

[Hydrops fetalis caused by isoimmunization against Kell factor (author's transl)]

The article reports on a case of hydrops fetalis caused by Kell antibodies, antibody formation having been triggered by pregnancy. Since the relative frequency of Kell (and rhesus sub-group) intolerance is increasing due to the successes achieved by anti-D-immunoglobulin prophylaxis, the question arises, on account of the possibly severe course of the disease, whether the Kell factor should be taken into consideration in all blood transfusions in girls during their childhood and in women of childbearing age.

Optimization of the regular frequency of the heart in atrial fibrillation in relation to the cardiac output

In atrial fibrillation an optimal frequency value has been derived to give the maximum cardiac output. A multiple, non-linear regression analysis of phasic aortic flow velocity in 12 patients with atrial fibrillation yields the parameters: (i) upper limiting frequency, fc; and (ii) 'optimal' frequency of the heart fo = fc/2. fo is defined at maximum cardiac output in resting conditions. An estimate of fc may be obtained from the carotid pulse tracing in a non-invasive way for the individual patient. The maximum cardiac output at fo ranges between 100% and 125% of the cardiac output was measured in the atrial fibrillatory state with irregular excitation of the ventricles. The greater the degree of irregularity of atrial fibrillation, the more expressed was the potential rise in cardiac output at the optimal regularization frequency. In chronic atrial fibrillation a regular excitation of the ventricles could be achieved by pharmacological agents, such as Verapamil or by ventricular pacing, without restitution of normal sinus rhythm. In critically ill patients with atrial fibrillation and the low cardiac output syndrome the heart rate should be adjusted to the individual cardiac output-related optimal frequency.

Lung function studies in a patient with diffuse pulmonary fibroleiomyomas

Diffuse pulmonary fibroleiomyomas were detected by open-lung biopsy in a 33-year-old male patient. Lung function studies revealed severe airflow obstruction, hyperinflation, grossly impaired single-breath-diffusing capacity and a decrease in PaO2 during exercise, i.e. data which are compatible with pulmonary emphysema. However, static lung compliance was within normal limits excluding the existence of pure emphysema. Additional special lung function tests confirmed the assumption that in diffuse fibroleiomyomas of the lung, functional patterns characteristic of obstructive and restrictive lung disease are present that are in agreement with the histological features of this disease.

[Echocardiographic diagnosis of malfunction of the Björk-Shiley prosthetic heart valve in the mitral position (author's transl)]

In patients with mitral valve replacement an acute cardiac decompensation most often signalizes malfunction of the prosthesis. Echocardiography proves to be of great value in the noninvasive diagnostic to detecting valve dysfunction. The echocardiogram of two patients few weeks after cardiac surgery was strongly suggestive of perivalve leak with severe regurgitation: enlarged left atrium and left ventricle, hyperactive septal motion and hyperkinetic motion of the left ventricular posterior wall, unique "hump" in early diastole with normal excursion, opening and closing velocity of the disc. The echocardiogram of one patient exhibited the pattern of mitral stenosis: large left atrium, decreased amplitude of excursion of the opening of the disc with a slowing and "rounded" opening upstroke as well as a slowed and "rounded" downstroke with prolonged opening and closing rates of the disc. One patient with aortic and mitral valve replacement showed no echocardiographic signs of abnormal disc motion. The reason for the cardiac decompensation was an acute malfunction of the left ventricle. The echocardiographic findings were confirmed by cardiac catheterization, left ventricular cineangiography or direct inspection during open heart surgery.

[Exercise capacity and physical activity following prosthetic valve replacement in relation to cardiovascular function (author's transl)]

31 patients (Pt) with Mitral Valve Repacement (MVR), 22 Pt with Aortic VR (AVR) and 10 Pt with Double VR (DVR) are investigated hemodynamically and by ergometry. Normal working capacity (100% WC) has been achieved in 59% of Pt with AVR, in 34% with MVR and in 22% with DVR. Pulmonary artery mean pressure (PAMP) in this group was 19.5 mmHg, in a second group with a WC of 80% PAMP was 22.2 mmHG. 77% OF Pt with AVR are working regularly, in MVR 58% and in DVR 50%. In the average of these Pt, 7 months after VR professional occupation is started again. PAMP and pulmonary vascular resistance (APR) is significantly lower in the working vs. the non working group: PAMP 19.8/23.7 mmHg; APR 115/145 dynes sec cm-5, respectively. In MVR, the transprosthetic pressure gradient at rest was 4.1 (working PPT) and 7.5 mmHg (other); in AVR statistically no significant difference in the gradient could be found. In general, 68% of the working Pt are employed in a preferably sedentary job. The mean duration of daily work was estimated to 6.7 hours. It is concluded that AVR yields more favourable results in terms of regaining normal working activity than MVR. Cardiovascular function and physical capability in Pt with DVR are approximately comparable to MVR.

[Pseudodystrophic muscle glycogenosis in adults. (Acid maltase deficiency syndrome) (author's transl)]

A 40-year-old man suffered for 5 years from a progressive proximal myopathy mimicking an atypical limb-girdle dystrophy. A "myopathic" pattern with myotonic and pseudomyotonic discharges was determined by electromyography. Enzyme histochemical and ultrastructural investigations of muscle and liver biopsies pointed to a glycogenosis. Biochemical investigations of muscle and liver samples confirmed this diagnosis, disclosing an acid maltase deficiency. Glycogen filled lysosomes were also revealed electron optically in skin fibroblasts but not in white blood cells. The literature concerning the late onset forms of acid maltase deficiency (type II glycogenosis) has been reviewed, and the clinical course has been compared with that of the infantile form (Pompe's disease). In early infancy the disease has a short and fatal course, with involvement of many organs. primarily skeletal muscules, liver and heart. In the late infantile and juvenile forms the course of the disease is slower, the organ involvement beeing not as severe; muscular symptoms begin to prevail. In adults, type II glycogenosis mimics muscular dystrophy with its prolonged course and the almost exclusive clinical involvement of proximal muscles. Biochemical and ultrastructural investigations have nevertheless demonstrated that other organs and tissues are also involved. The reasons for the variability of organ involvements in different ages are as yet unknown.