Correlation of skeletal muscle blood oxygenation level-dependent MRI and skin laser Doppler flowmetry in patients with systemic sclerosis.

PURPOSE: To investigate the origin of skeletal muscle BOLD MRI alterations in patients with systemic sclerosis (SSc) by correlating BOLD MRI T2* signal of calf muscles with microcirculatory blood flow of calf skin measured by laser Doppler flowmetry (LDF). MATERIALS AND METHODS: BOLD MRI (3T) and LDF measurements were performed in 12 consecutive SSc patients (6 women, 6 men; mean age 54.0 ± 10.0 years) and 12 healthy volunteers (4 men, 8 women; mean age 44.7 ± 13.1 years). For both modalities, the same cuff compression paradigm at mid-thigh level was used. LDF datasets were acquired using a PeriScan PIM II Imager (Perimed AB, Stockholm, Sweden) at the upper calf corresponding to the level of MR imaging. Cross-correlations of BOLD and LDF signal intensity changes depending on time lags between both time series were calculated. RESULTS: Maximal cross-correlations of BOLD T2* and LDF measurements were calculated as 0.93 (healthy volunteers) and 0.94 (SSc patients) for a BOLD time lag of approximately 10 s. Key parameter analysis suggested that in contrast to hyperemic BOLD signal loss at maximum value in SSc patients, ischemic T2* decrease cannot be explained by differences of tissue perfusion. CONCLUSION: Skeletal muscle BOLD T2* signal in SSc patients is closely correlated with changes of microperfusion as detected by LDF.

Impaired skeletal muscle microcirculation in systemic sclerosis.

INTRODUCTION: Muscle symptoms in systemic sclerosis (SSc) may originate from altered skeletal muscle microcirculation, which can be investigated by means of blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI). METHODS: After ethics committee approval and written consent, 11 consecutive SSc patients (5 men, mean age 52.6 years, mean SSc disease duration 5.4 years) and 12 healthy volunteers (4 men, mean age 45.1 years) were included. Subjects with peripheral arterial occlusive disease were excluded. BOLD MRI was performed on calf muscles during cuff-induced ischemia and reactive hyperemia, using a 3-T whole-body scanner (Verio, Siemens, Erlangen, Germany) and fat-suppressed single-short multi-echo echo planar imaging (EPI) with four different effective echo times. Muscle BOLD signal time courses were obtained for gastrocnemius and soleus muscles: minimal hemoglobin oxygen saturation (T2*min) and maximal T2* values (T2*max), time to T2* peak (TTP), and slopes of oxygen normalization after T2* peaking. RESULTS: The vast majority of SSc patients lacked skeletal muscle atrophy, weakness or serum creatine kinase elevation. Nevertheless, more intense oxygen desaturation during ischemia was observed in calf muscles of SSc patients (mean T2*min -15.0%), compared with controls (-9.1%, P = 0.02). SSc patients also had impaired oxygenation during hyperemia (median T2*max 9.2% vs. 20.1%, respectively, P = 0.007). The slope of muscle oxygen normalization was significantly less steep and prolonged (TTP) in SSc patients (P<0.001 for both). Similar differences were found at a separate analysis of gastrocnemius and soleus muscles, with most pronounced impairment in the gastrocnemius. CONCLUSIONS: BOLD MRI demonstrates a significant impairment of skeletal muscle microcirculation in SSc.

Contrast-enhanced ultrasound for assessing carotid atherosclerotic plaque lesions.

OBJECTIVE: Contrast-enhanced ultrasound that is used to assess atherosclerotic carotid plaques improves visualization of vessel wall irregularities and provides direct visualization of intraplaque neovascularization. This article illustrates the use of contrast-enhanced ultrasound in the assessment of carotid atherosclerotic lesions. CONCLUSION: Contrast-enhanced ultrasound is a new, noninvasive, and safe procedure for imaging carotid atherosclerotic lesions. It is a valuable tool for evaluating the vulnerable plaque at risk for rupture and for evaluating both the development and severity of systemic atherosclerotic disease.

Effect of silver-threads-containing compression stockings on the cutaneous microcirculation: a double-blind, randomized cross-over study.

Recently silver fiber-containing compression stockings for the use in patients with chronic venous insufficiency (CVI) were introduced to the market. In order to gain some first insight into the effects of these new fabrics on the cutaneous microcirculation, a double-blind, randomized cross-over trial was performed in 10 healthy volunteers. A 3 days run-in phase preceded the (2 x10 days) treatment phases and was used to assess the reproducibility of the primary endpoint, which was the transcutaneous partial oxygen pressure (tcpO(2)) measured at a probe temperature of 44 degrees C in the perimalleolar region of the reference leg in supine and dependent leg positions. Coefficients of variation for double measured tcpO(2) values were 4.2% (3.1 SD) and 5.8% (6.0 SD) for the leg in supine and dependent position. The intra-individual comparison of the effects from both treatment phases (value end of treatment - start of treatment) resulted in a negative tcpO(2) net balance for the regular hosiery (-0.93 (2.7 SD) mmHg, supine; -1.1 (3.5 SD) mmHg, dependent) but a positive net balance for the silver fibers containing stockings (0.25 (4.0 SD) mmHg, supine; 1.7 (3.9 SD) mmHg, dependent). The inter-treatment differences were statistically significant for the leg in a dependent position. The trial provides first evidence that interweaving silver threads into regular compression stockings may result in a positive effect regarding the nutritive skin perfusion.

Blood oxygenation level-dependent magnetic resonance imaging of the skeletal muscle in patients with peripheral arterial occlusive disease.

BACKGROUND: Blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) has been used to measure T2* changes in skeletal muscle tissue of healthy volunteers. The BOLD effect is assumed to primarily reflect changes in blood oxygenation at the tissue level. We compared the calf muscle BOLD response of patients with peripheral arterial occlusive disease (PAOD) to that of an age-matched non-PAOD group during postischemic reactive hyperemia. METHODS AND RESULTS: PAOD patients (n=17) with symptoms of intermittent calf claudication and an age-matched non-PAOD group (n=11) underwent T2*-weighted single-shot multiecho planar imaging on a whole-body magnetic resonance scanner at 1.5 T. Muscle BOLD MRI of the calf was performed during reactive hyperemia provoked by a cuff-compression paradigm. T2* maps were generated with an automated fitting procedure. Maximal T2* change (deltaT2*(max)) and time to peak to reach deltaT2*(max) for gastrocnemius, soleus, tibial anterior, and peroneal muscle were evaluated. Compared with the non-PAOD group, patients revealed significantly lower deltaT2*(max)-values, with a mean of 7.3+/-5.3% versus 13.1+/-5.6% (P<0.001), and significantly delayed time-to-peak values, with a mean of 109.3+/-79.3 versus 32.2+/-13.3 seconds (P<0.001). CONCLUSIONS: T2* time courses of the muscle BOLD MRI signal during postocclusive reactive hyperemia revealed statistically significant differences in the key parameters (deltaT2*(max); time to peak) in PAOD patients compared with age-matched non-PAOD controls.

Infragenual cuff-compression reduces venous contamination in contrast-enhanced MR angiography of the calf.

PURPOSE: To reduce venous contamination at the calf level in three-dimensional contrast-enhanced MR angiography (CE-MRA) by applying continuous infragenual cuff-compression. MATERIALS AND METHODS: Ten patients with clinically relevant peripheral arterial occlusive disease (PAOD) underwent dynamic three-dimensional CE-MRA of the calf. Six consecutive measurements were acquired with the first measurement serving as mask. Cuff-compression of 50 mmHg was attached below the knee. To allow intra-individual comparison, compression was applied unilaterally. The cuff was inflated three minutes before scanning and was continued throughout the MRA session. Venous contamination and arterial visualization scores were ranked using a five-point rating scale. Contrast-to-noise ratios (CNRs) of superficial enhancing calf-veins on the uncompressed and compressed calf sides were evaluated. An asymmetry index (AI) defined by CNR(mean) (uncompressed)/CNR(mean) (compressed) was introduced to describe the ratio in venous contrast agent supply between both sides quantitatively. RESULTS: Three-dimensional CE-MRA of the calves demonstrated significantly lower superficial venous contamination scores (P < 0.004) and clearly improved arterial visualization (P < 0.009) on the compressed side. Additionally, AI values were larger than 1 (P < 0.02), indicating a higher contrast agent supply in the superficial veins on the uncompressed side. CONCLUSION: Infragenual cuff-compression minimizes venous overlay in three-dimensional CE-MRA at calf level by reduction of contrast agent supply in the superficial veins.

Great saphenous vein stripping with liberal use of subfascial endoscopic perforator vein surgery (SEPS).

This study is based on a unique registry of 632 patients who underwent great saphenous vein (GSV) stripping and liberal use of subfascial endoscopic perforator vein surgery (SEPS) for minimal to severe lower limb venous insufficiency. Clinical examinations and color-coded duplex scanning were performed on a randomly selected, manageable sample of 170 limbs to assess the affect of early SEPS on junctional (saphenofemoral [SFJ] and/or saphenopopliteal [SPJ]) and perforator vein (PV) insufficiencies and superficial varicosities at a median of 6.5 years. PV incompetence was present in 68 legs (40%), as the sole transfascial insufficiency in 28 limbs and combined with SFJ or SPJ incompetence in 40 limbs. Junction incompetence alone characterized an additional 38 limbs, bringing the total transfascial insufficiency prevalence to 62%. Superficial varicosities affected 46% of limbs. Overall CEAP clinical class was unimproved beyond preoperative values. PV incompetence was associated with higher CEAP and clinical venous severity scores than were junctional insufficiencies alone. We concluded that PV incompetence alone or combined with junctional insufficiency is associated with increased symptoms and disease progression. The prevalence of SFJ, SPJ, and PV incompetence (62%) and recurrent varicosities (46%) suggests that early use of SEPS does not prevent disease progression and offers no benefit over GSV stripping in the absence of deep vein insufficiency or threatened ulceration.