Automatic left ventricular volume measurements on contrast-enhanced ultrafast cine magnetic resonance imaging.

To assess the accuracy of automatic extraction of the left ventricular inner contour on contrast-enhanced ultrafast cine magnetic resonance (MR) images, we compared the values obtained by this method with those obtained using intravenous digital subtraction left ventriculography. High-quality single breath-hold contrast-enhanced ultrafast cine MR images were obtained in all cardiac phases on horizontal and vertical long axis sections of the left ventricle. For ultrafast cine MR imaging, a phase-rewind gradient-echo (rewind-SMASH) sequence was used. Automatic extraction of the left ventricular inner contour on contrast-enhanced ultrafast cine MR images was performed in all cardiac phases. High-quality left ventricular images of the horizontal long axis section were obtained in 127 of 160 patients (79%). The automatic extraction of the left ventricular contour was easily performed on high-quality images with very short processing time (4 s/frame). The values for left ventricular volumes obtained with the automatic extraction method on contrast-enhanced ultrafast cine MR imaging were correlated well with those obtained with the manual extraction method and IV-DSA in high quality cardiac images. The biplane modified Simpson's method using automatic extraction is an accurate and highly reproducible method for evaluating left ventricular volumes.

[Left ventricular hemodynamics in patients with sick sinus syndrome: analysis by 99mTc-RBC cardiac pool scintigraphy with forward and backward multiple gated method (FBMG)].

The left ventricular (LV) systolic and diastolic functions in 31 patients with sick sinus syndrome (types I and II) were analyzed using LV time activity curves obtained by a 99mTc-RBC cardiac pool scintigraphy-forward and backward multiple gated study (FBMG) and compared with those in controls. On A-V sequential pacing (rate, 70 bpm; A-V delay, 150 msec), LV-peak ejection rate (PER) and peak filling rate (PFR) were significantly decreased compared to those in normal controls. As pacing rate was increased, PFR decreased significantly in patients in whom PER was decreased. The etiology of disturbed LV systolic and diastolic functions in patients with sick sinus syndrome remains unknown. No patient had significant organic coronary artery disease or other cardiac disorder. On the other hand, the frequency of vasospastic angina was higher in this group than in the controls. We suspect that sick sinus syndrome and vasospastic angina probably share a common pathophysiology. In patients with sick sinus syndrome, LV systolic and diastolic functions are impaired at rest and during A-V sequential pacing.

[Assessment of myocardial perfusion and cardiac sympathetic nerve dysfunction in patients with sick sinus syndrome--evaluation of coronary hemodynamics and 201TlCl/123I-MIBG myocardial SPECT].

To clarify the coronary hemodynamics, myocardial perfusion and cardiac sympathetic nerve function in patients with sick sinus syndrome (SSS), we performed left coronary digital subtraction angiography (DSA) in 41 patients, exercise 201TlCl-myocardial scintigraphy (planar and SPECT) in 69 patients, and 201TlCl/123I-MIBG myocardial dual SPECT in 13 patients without significant organic coronary stenosis. Coronary artery spasm was documented on coronary angiography in 25/43 (58%) patients with SSS by ergonovine provocation test. Compared with normals, patients with SSS demonstrated prolongation of left coronary circulation time (CCT) on own heart beats and right atrial pacing. We suspected that prolonged CCT may be induced by increased peripheral coronary vascular resistance and impaired coronary microcirculation in patients with SSS. Forty-two patients (60.9%) developed exercise-induced 201Tl-myocardial perfusion defect on SPECT images. On myocardial dual SPECT images, 11/13 (85%) patients showed localized myocardial low uptake in 123I-MIBG-SPECT images. In eight patients with normal findings on 201Tl-SPECT, six patients showed abnormality on 123I-MIBG-SPECT. We suspected that coronary vasospasm, impaired coronary micro-circulation and cardiac sympathetic nerve dysfunction are taken a part of pathophysiology in SSS (decreased beta-adrenergic receptor of peripheral coronary arteries?).

[Evaluation of coronary hemodynamics and exercise 201Tl-myocardial scintigraphy in patients with vasospastic angina].

To clarify the coronary hemodynamics and myocardial perfusion in patients with vasospastic angina, we performed exercise-201Tl-myocardial scintigraphy (planar and SPECT) in 72 patients and left coronary digital subtraction angiography (DSA) in 37 patients without significant organic coronary artery stenosis. Coronary artery spasm was documented by coronary angiography in all patients. Fifty-four patients (75%) developed exercise-induced 201Tl-myocardial perfusion defect on SPECT. 201Tl pulmonary uptake (L/H) was significantly increased in patients with vasospastic angina. Especially, L/H was higher in patients with multiple small perfusion defect on 201Tl-SPECT, so that exercise-induced left ventricular dysfunction existed in patients with vasospastic angina and especially in cases with multiple small perfusion defect on 201Tl-SPECT. The left coronary circulation time (CCT) was prolonged in patients with vasospastic angina. The mechanism of prolonged CCT is still unknown, but we suspected that prolonged CCT was induced by increased peripheral coronary vascular resistance in patients with vasospastic angina. It was concluded that the peripheral coronary circulation was disturbed in patients with vasospastic angina, but its abnormal coronary circulation had no relation to location of spasm-induced vessels. We concluded that impaired coronary microcirculation was taken a part of pathophysiology in vasospastic angina.

[The graft flow and 201Tl-myocardial scintigram in patients with saphenous vein graft or left internal thoracic artery graft].

To evaluate myocardial perfusion in patients with saphenous vein graft (SVG) or internal thoracic artery graft (ITA-G), we studied 38 patients (14: SVG, 10 males and 4 females, mean age 66 +/- 9 y-o; 24: ITA-G, 18 males and 6 females, mean age 64 +/- 7 y-o) by digital subtraction angiography (DSA) of ITA-G or SVG, and thallium-201 myocardial perfusion scintigraphy on exercise or dipyridamole stress. The grafting sites were left anterior descending artery (LAD) in all patients. Normal controls (n = 22) were defined by normal coronary angiogram and no evidence of myocardial ischemia. The graft flow and flow reserve on dipyridamole were measured by Rutishauser's formula. The basal blood flow of native normal ITA, SVG and ITA-G were respectively 72 +/- 24 ml/min, 51 +/- 23 ml/min, and 36 +/- 20 ml/min. The basal ITA-G flow was significantly lower than SVG-flow (p < 0.05). The flow reserves of SVG and ITA-G were respectively 2.32 +/- 0.65 and 1.78 +/- 0.59 (p < 0.02). The incidence of moderate hypoperfusion of thallium-201 SPECT was 14.3% in SVG and 12.5% in ITA-G on exercise stress, and 35% in SVG and 50% in ITA-G on dipyridamole stress. The incidence of reversible myocardial ischemia on dipyridamole stress was significant. The graft flow in patients with normal and abnormal thallium-201 SPECT were respectively 61 +/- 21 ml/min and 33 +/- 15 ml/min in SVG (p < 0.01), 46 +/- 19 ml/min and 27 +/- 16 ml/min in ITA-G (p < 0.02). The graft flow reserve were respectively 2.69 +/- 0.38 and 1.65 +/- 0.49 in SVG (p < 0.001), 2.25 +/- 0.40 and 1.31 +/- 0.28 in ITA-G (p < 0.001). We concluded that the basal blood flow and flow reserve of ITA-G were significantly lower than those of SVG. The myocardial ischemia was occasionally documented by the thallium-201 myocardial SPECT on dipyridamole stress in patients with patent ITA-G.

[Thyroid hormones and thyroid-stimulating hormone in patients with chronic heart failure--relationship between primary hypothyroidism with iodine organification defect and chronic heart failure].

Serum concentrations of triiodothyronine (T3), thyroxine (T4) and thyroid-stimulating hormone (TSH) were measured in 127 patients with chronic heart failure (CHF) (left ventricular ejection fraction; 40% < or = and NYHA; III-IV), and 1,079 patients without CHF (non-CHF) (left ventricular ejection fraction; 40% < or = and NYHA; I-II). Serum-T3, T4 and free-T4 were significantly decreased in patients with CHF. The prevalence of slight increase of serum TSH (5 < or = TSH < 15 microU/ml) were 20.5% in CHF and 4.08% in non-CHF. There was a statistically significant difference in the prevalence of slight increase of TSH (p < 0.01). In the patients with slight increase of serum TSH, the 123I-thyroid scintigraphy and perchlorate test were performed 12 patients with CHF and 19 patients with non-CHF. The incidences of iodine organification defect were 33.3% in CHF and 5.26% in non-CHF. There was a statistically significant difference in the incidence of iodine organification defect (p < 0.05). The histologic examination of thyroid biopsy specimen obtained 12 patients with CHF and primary hypothyroidism, these revealed only non-specific mild atrophic changes. Follicular damage and lymphocyte-infiltration were not evident. These findings suggest that the primary hypothyroidism were frequently complicated in CHF and associated with iodine organification defect by reduction of thyroid-peroxidase activity or decrease of hydrogen peroxidase. We conclude that the primary hypothyroidism with iodine organification defect was probably developed as a result of CHF.

[Assessment of coronary hemodynamics and myocardial perfusion in patients with syndrome X by digital subtraction angiography and 201Tl-myocardial scintigraphy].

To evaluate coronary hemodynamics and myocardial perfusion, left coronary digital subtraction angiography (DSA) and Tl-201 myocardial scintigraphy were performed in patients with syndrome X. The coronary circulation time (CCT) was significantly prolonged after the injection of isosorbide dinitrate and contrast medium i.c. Apical T1/2 was also prolonged on ergonovine malate provocation test. We suspected that the vascular response of the coronary peripheral artery was impaired, and microvascular spasm probably existed in patients with syndrome X. The prevalence of abnormal myocardial perfusion defect on exercise Tl-201 SPECT in syndrome X was very high, and coronary hemodynamics was significantly disturbed in the group of syndrome X with abnormal Tl-201 SPECT. Tl-201 lung/heart count ratio significantly increased in syndrome X on treadmill test. Because of this, exercise induced left ventricular dysfunction was suspected. We concluded that the main pathophysiological finding of impaired coronary circulation in syndrome X was microvascular spasm.

[Coronary hemodynamics in vasospastic angina: quantitative analysis by digital subtraction angiography].

To evaluate the coronary circulation and myocardial perfusion dynamics, we performed left coronary digital subtraction angiography (DSA) in 35 patients with vasospastic angina. The left coronary circulation time (CCT) measured from the proximal left coronary artery to the coronary sinus was 5.77 +/- 0.86 sec, and the left epicardial conducting artery transmission time (CAT) measured from the proximal left coronary artery to the apical area was 2.65 +/- 0.82 sec in normal controls. The CCT and CAT were significantly prolonged in patients with vasospastic angina, indicating that the coronary peripheral vascular resistance is probably greater after the cessation of nitrates and Ca(++)-antagonists. After the intracoronary injection of ergonovine malate, the CCT was slightly shortened, but the apical T1/2 was significantly prolonged in patients with vasospastic angina. This suggested that coronary vasospasm is present not only in the epicardial arteries but also in coronary arteries with peripheral resistance. These phenomena were not observed in normal controls. We performed left coronary DSA after conventional left coronary cineangiography. When the CCT exceeded 6.7 sec, we considered that the coronary circulation was significantly impaired. We concluded that the coronary DSA is very useful for evaluating abnormal coronary circulation in patients with vasospastic angina during myocardial perfusion.

Determination of cardiac ejection fraction and left ventricular volume: contrast-enhanced ultrafast cine MR imaging vs IV digital subtraction ventriculography.

OBJECTIVE: To assess the accuracy of contrast-enhanced, single breath-hold cine MR imaging in the calculation of left ventricular volume and ejection fraction, we compared values obtained by using this method with those obtained by using IV digital subtraction angiography (IV-DSA). SUBJECTS AND METHODS: All patients (n = 28) had conventional cine and contrast-enhanced ultrafast cine MR imaging. For ultrafast cine MR imaging, a phase-rewind gradient-echo (rewind-SMASH) sequence was used: TR, 8 msec (standard excitation and acquisition block of 6 msec with phase rewind pulse of 2 msec); TE, 3.2 msec; a 128 x 96 matrix (pile encode factor, 6; k-space segment, 16); a 200-mm field of view; and one excitation. RESULTS: Values for left ventricular volume and ejection fraction obtained with ultrafast cine MR imaging correlated well with those obtained with IV-DSA (end-diastolic volume, y = 0.986x - 7.79, r = .985; end-systolic volume, y = 0.863x + 0.71, r = .984; ejection fraction, y = 0.877x + 6.44, r = .887). In the calculation of left ventricular volume by the area-length method, manual tracing of the left ventricular cavity was more difficult when the conventional cine method was used than when the enhanced ultrafast cine method was used. CONCLUSION: Our results show that cardiac multiphase study with horizontal long-axis, first-pass, contrast-enhanced, single breath-hold, cine MR imaging is an accurate and highly reproducible method of evaluating left ventricular volume and ejection fraction.