Nishikawa J

Reduced Myocardial Flow Reserve in Non–Insulin-Dependent Diabetes Mellitus

OBJECTIVES We analyzed myocardial flow reserve (MFR) in patients with non-insulin-dependent (type II) diabetes mellitus (NIDDM) without symptoms and signs of ischemia. BACKGROUND Diminished MFR in diabetes has been suggested. However, it remains controversial whether MFR is related to glycemic control, mode of therapy or gender in NIDDM. METHODS Myocardial blood flow (MBF) was measured at baseline and during dipyridamole loading in 25 asymptomatic, normotensive, normocholesterolemic patients with NIDDM and 12 age-matched control subjects by means of positron emission tomography and nitrogen-13 ammonia, after which MFR was calculated. RESULTS Baseline MBF in patients with NIDDM ([mean +/- SD] 74.0 +/- 24.0 ml/min per 100 g body weight) was comparable to that in control subjects (73.0 +/- 17.0 ml/min per 100 g). However, MBF during dipyridamole loading was significantly lower in patients with NIDDM (184 +/- 99.0 ml/min per 100 g, p < 0.01) than in control subjects (262 +/- 120 ml/min per 100 g), as was MFR (NIDDM: 2.77 +/- 0.85; control subjects: 3.8 +/- 1.0, p < 0.01). A significantly decreased MFR was seen in men (2.35 +/- 0.84) compared with women with NIDDM (3.18 +/- 0.79, p < 0.05); however, no significant differences were found in terms of age, hemoglobin a1c and baseline MBF. MFR was comparable between the diet (2.78 +/- 0.80) and medication therapy groups (2.76 +/- 0.77) and was inversely correlated with average hemoglobin A1c for 5 years (r = -0.55, p < 0.01) and fasting plasma glucose concentration (r = -0.57, p < 0.01) but not age or lipid fractions. CONCLUSIONS Glycemic control and gender, rather than mode of therapy, is related to MFR in NIDDM.

Reduced coronary flow reserve in hypercholesterolemic patients without overt coronary stenosis.

BACKGROUND Reduced coronary flow reserve (CFR) in hypercholesterolemic patients without evidence of ischemia has been reported. However, it remains uncertain whether this abnormality occurs without overt coronary atherosclerosis. This study aimed to clarify whether CFR is impaired even in anatomically normal coronary arteries in hypercholesterolemic patients and to compare CFR between familial hypercholesterolemic (FH) patients and secondary hypercholesterolemic (SH) patients. METHODS AND RESULTS Twenty-two patients with hypercholesterolemia (11 FH, 11 SH) and 11 control subjects were studied. Baseline myocardial blood flow (MBF) and MBF during dipyridamole loading were measured in segments perfused by angiographically normal coronary arteries with the use of positron emission tomography and 13N-ammonia, and CFR was calculated. Baseline MBF (mL/min per 100 g heart wt) in FH (81.3 +/- 31.4) and SH (70.0 +/- 20.7) patients was not different from that in control subjects (75.0 +/- 34.9). However, MBF during dipyridamole loading was significantly lower in FH patients (129 +/- 19.1) than in control subjects (322 +/- 174, P < .01) and SH patients (210 +/- 71.2, P < .01). CFR in FH patients (1.59 +/- 0.41) was also significantly lower compared with both control subjects (4.22 +/- 1.42, P < .01) and SH patients (3.00 +/- 0.96, P < .01). CFR in SH patients was also significantly lower than that in control subjects (P < .05). CFR correlated significantly with both plasma total cholesterol (r = .67, P < .01) and LDL cholesterol concentrations (r = .69, P < .01). CONCLUSIONS CFR was decreased even in anatomically normal coronary arteries in hypercholesterolemic patients. This abnormality was more prominent in FH patients.

Hyperglycemia Rather Than Insulin Resistance Is Related to Reduced Coronary Flow Reserve in NIDDM

To clarify if coronary flow reserve (CFR) is related to insulin resistance or hyperglycemia in normotensive NIDDM, myocardial blood flow (MBF) at baseline and during dipyridamole loading were measured with 13N-ammonia positron-emission tomography. CFR was significantly reduced in NIDDM patients compared with agematched control subjects. CFR in patients with well-controlled NIDDM was significantly higher than in those with poorly controlled NIDDM, whereas insulin resistance was comparable between the two groups. CFR in NIDDM patients was not related to the degree of insulin resistance. CFR correlated significantly with average fasting glucose concentration and average HbA1c, but not with insulin resistance, age, lipid parameters, or blood pressure. In conclusion, control of blood glucose concentration rather than insulin resistance is most likely related to the reduced CFR in NIDDM.

Congenital absence of the portal vein

Absence of the terminal portion of the portal vein and its intrahepatic branches was demonstrated in a 22-year-old woman with focal nodular hyperplasia (FNH) of the liver. Various imaging studies and angiography showed that the portal vein entered into the inferior vena cava just above the renal veins. The clinical and radiological features of this patient and nine previously reported cases of this entity are herein reviewed.

New subtype of apical hypertrophic cardiomyopathy identified with nuclear magnetic resonance imaging as an underlying cause of markedly inverted T waves

OBJECTIVES The aim of this study was to elucidate the clinical importance of a new subtype of apical hypertrophic cardiomyopathy that could not be diagnosed with the classical diagnostic criteria. BACKGROUND Apical hypertrophic cardiomyopathy is recognized by a characteristic spade-shaped intraventricular cavity on the end-diastolic left ventriculogram in the right anterior oblique projection, often associated with giant negative T waves [negativity > or = 1.0 mV (10 mm)]. As an underlying cause of giant negative T waves, an additional new subtype of apical hypertrophic cardiomyopathy has been identified. METHODS In 40 patients with inverted T waves (negativity > or = 0.5 mV), including 26 patients with giant negative T waves, nuclear magnetic resonance (NMR) long-axis images corresponding to the left ventriculogram in the right anterior oblique projection and short-axis images at various levels, including the apical level, were obtained to define the site of hypertrophied myocardium. RESULTS Long-axis images indicated a spadelike configuration in 17 patients, whereas this diagnostic configuration was not present in the other 23 patients. Nine of these 23 patients had significantly hypertrophied myocardium at the basal level. In the 14 remaining patients, short-axis images indicated no hypertrophy at the basal level and proved that the area of hypertrophied myocardium was confined to a narrow region of the septum or the anterior or lateral wall at the apical level (nonspade apical hypertrophic cardiomyopathy). The hypertrophied myocardium of the nonspade type was so narrowly confined that the mass did not form a spadelike configuration or could not be detected on the long-axis image. CONCLUSIONS Nonspade apical hypertrophic cardiomyopathy was newly identified on NMR short-axis images, and this could be an additional, important underlying cause of moderately to severely inverted T waves.

Neural network mapping for nonlinear stereotactic normalization of brain MR images.

We present techniques of automatic nonlinear transformation of MR images (2D or 3D). A neural network automatically finds the corresponding parts between the subjects brain images and the standard images. By iterative operations, the network generates a set of image-shifting vectors to realize a plastic transformation. For precise matching, a set of markers can be placed manually before starting the transformation on landmarks of the images, e.g., on the anterior-posterior commissural line and on the central sulcus.

Scintigraphic manifestation of fibrous dysplasia

Scintigraphic manifestations of fibrous dysplasia were analyzed in 59 lesions of 26 patients (12 monostotic, 14 polystotic). Bone imaging with Tc-99m MDP revealed a high percentage of increased uptake of radioisotope in the lesions of fibrous dysplasia. Four (14%) of 29 cystic lesions and two (7%) of 30 lesions with the appearance of ground glass showed no increase in radioisotope uptake, although roentgenograms showed marked changes. Therefore, care must be taken in the diagnosis of fibrous dysplasia with bone imaging alone. Nuclear methods, however, are indispensable in evaluating the dynamic aspects of bone mineral behavior and in demonstrating disease where none was suspected, or in visualizing polyostotic involvement in those cases where only monostotic disease was suspected clinically. It is concluded that both scintigrams and roentgenograms are complementary procedures in the diagnosis of fibrous dysplasia.

Computed Tomography in the Evaluation of Hepatocellular Carcinoma

Computed tomography (CT) was used to evaluate 47 cases of hepatocellular carcinoma: it was definite in 37, equivocal in 5 and negative in 5 cases. No specific patterns of CT images were recognized. Pre- and postcontrast scans were necessary because several tumors could only be detected on one or the other scan. CT may reveal the exact extent of tumor and show additional tumors in case of multiple lesions. However, false negative results are possible in isodense or very small tumors.

Relationship between distribution of hypertrophy and electrocardiographic changes in hypertrophic cardiomyopathy

To assess the relationship between the distribution of hypertrophy and electrocardiographic changes in patients with hypertrophic cardiomyopathy, magnetic resonance imaging and ECG findings were correlated in 25 patients with apical hypertrophy (group I), 15 patients with both apical and basal hypertrophy (group II), and 11 patients with hypertrophy localized to the basal left ventricle (group III). The number of precordial leads with negative T waves (-0.5 mV or more) was greater in group I than in groups II and III (I = 3.0 +/- 1.5, II = 1.7 +/- 1.5, III = 0.3 +/- 0.6; p < 0.01). Giant negative T waves (-1.0 mV or more) in precordial leads were found in 13 patients (52%) in group I and five patients (33%) in group II but were not found in group III. In contrast, tall positive T waves (> or = 1.0 mV) in precordial leads were found in two patients (13%) in group II and five (45%) in group III but were not found in group I. These results suggest that the distribution of hypertrophy in patients with hypertrophic cardiomyopathy produces a particular T wave polarity in precordial leads.

Impaired Myocardial Vasodilation During Hyperemic Stress With Dipyridamole in Hypertriglyceridemia

OBJECTIVES This study sought to investigate the specific role of hypertriglyceridemia in the myocardial hyperemic stress with dipyridamole/rest flow ratio (MDR). BACKGROUND Reduced MDR has been reported in hypercholesterolemic patients without evidence of ischemia. However, the specific role of hypertriglyceridemia in MDR has not been studied. METHODS Fifteen nondiabetic normocholesterolemic hypertriglyceridemic patients and 13 age-matched control subjects were studied. Myocardial blood flow (MBF) during dipyridamole administration and baseline MBF in hypertriglyceridemic patients and control subjects were measured using positron emission tomography and nitrogen-13 ammonia, after which the MDR was calculated. RESULTS Baseline MBF (ml/min per 100 g heart weight) in hypertriglyceridemic patients (mean +/- SD 73.6 +/- 24.1) did not differ significantly from that in control subjects (81.6 +/- 37.2). MBF during dipyridamole loading in hypertriglyceridemic patients (198 +/- 106) was significantly reduced compared with that in control subjects (313 +/- 176, p < 0.05), as was the MDR (2.71 +/- 1.07 vs. 3.73 +/- 1.14, respectively, p < 0.05). Spearman rank-order correlation analysis showed a significant relation between plasma triglyceride concentration and MDR (r = -0.466, asymptotic SE 0.157, p = 0.0125); however, no such significant relation was seen between total plasma cholesterol concentration and MDR (r = -0.369, asymptotic SE 0.130, p = 0.059). CONCLUSIONS Impaired myocardial vasodilation was suggested in hypertriglyceridemic patients without symptoms and signs of ischemia.