Coronary artery anomalies with a shunt: evaluation with electron-beam CT

PURPOSE

Our goal was to evaluate the role of electron-beam CT (EBT) in the diagnosis of patients with coronary artery anomalies with a shunt.

METHOD

We performed EBT in seven patients with coronary artery anomalies with a shunt. Four cases were coronary artery fistula (CAF) and three were an anomalous origin of the left coronary artery from the pulmonary artery (ALCA from PA). Serial single volume mode scanning was performed at end-diastole to evaluate the anatomical course of the anomalous coronary arteries. Cine mode scanning was done in all but one to examine the ventricular wall motion and volumetrics.

RESULTS

EBT could detect the course and drainage sites of all CAFs and ALCAs from PA. Cine mode scanning revealed reduced wall motion in one case with CAF and two cases with ALCA from PA.

CONCLUSION

EBT serves a useful role in the assessment of coronary artery anomalies with a shunt.

Increased bone mineral turnover without increased glucose utilization in sclerotic and hyperplastic change in fibrous dysplasia

Fibrous dysplasia is a benign bone disorder. It is diagnosed by distinctive X-ray radiography, CT, and MRI findings. Although bone scintigraphy helps to identify the tumor origin according to accelerated bone turnover, the glucose metabolism in fibrous dysplasia has not yet been investigated. We reported a case of fibrous dysplasia in craniofacial bone which showed signs of the acceleration of bone mineral turnover without elevated glucose utilization by Technetium-99m-HMDP SPECT and Fluorine-18-FDG PET. We concluded that the growth of fibrous dysplasia needed the acceleration of bone mineral turnover without an increase in glucose metabolism.

Complete sequence and gene organization of the genome of a hyper-thermophilic archaebacterium, Pyrococcus horikoshii OT3

The complete sequence of the genome of a hyper-thermophilic archaebacterium, Pyrococcus horikoshii OT3, has been determined by assembling the sequences of the physical map-based contigs of fosmid clones and of long polymerase chain reaction (PCR) products which were used for gap-filling. The entire length of the genome was 1,738,505 bp. The authenticity of the entire genome sequence was supported by restriction analysis of long PCR products, which were directly amplified from the genomic DNA. As the potential protein-coding regions, a total of 2061 open reading frames (ORFs) were assigned, and by similarity search against public databases, 406 (19.7%) were related to genes with putative function and 453 (22.0%) to the sequences registered but with unknown function. The remaining 1202 ORFs (58.3%) did not show any significant similarity to the sequences in the databases. Sequence comparison among the assigned ORFs in the genome provided evidence that a considerable number of ORFs were generated by sequence duplication. By similarity search, 11 ORFs were assumed to contain the intein elements. The RNA genes identified were a single 16S-23S rRNA operon, two 5S rRNA genes and 46 tRNA genes including two with the intron structure. All the assigned ORFs and RNA coding regions occupied 91.25% of the whole genome. The data presented in this paper are available on the internet at http:@www.nite.go.jp.

[Usefulness of ECG-gated 99mTc-MIBI myocardial SPECT in the follow-up study of patients with acute myocardial infarction]

To clarify the background of the scintigraphic improvement in non-gated myocardial perfusion imaging for patients with acute myocardial infarction, we performed serial ECG-gated 99mTc-MIBI myocardial SPECT in 17 patients with acute myocardial infarction (AMI) receiving successful reperfusion therapy. ECG-gated myocardial SPECT and left ventriculography were performed at 1 week (acute phase) and 1 month (subacute phase) after the onset of AMI. Regional %uptake (regional count x 100/maximal count) was determined for each of 8 myocardial segments of the Bull's eye map. We analyzed the data in 53 AMI segments out of total 136 myocardial segments, on the non-gated (NG), end-diastolic (ED), and end-systolic (ES) images. In addition, the delta %uptake (%uptake in subacute phase--%uptake in acute phase) was also determined as an index representing the improvement of myocardial tracer uptake on each image. In 17 segments (group A) with wall motion recovery assessed by serial left ventriculography, the %uptake on the NG image was significantly improved (61.6 +/- 10.0 to 75.7 +/- 10.1, p < 0.0001). However, in 36 segments (group B) without wall motion recovery, the change of %uptake on the NG image was small. There was no significant change in the %uptake on the ED image in groups A and B. On the contrary, the %uptake on the ES image showed a significant increase in group A (58.4 +/- 11.8 to 68.9 +/- 11.8, p < 0.001), but did not in group B. Thus, this change on the ES image reflects the wall motion recovery. Furthermore, in group A, there was a significant correlation between the delta %uptake on the NG image and those on the ES image (p < 0.02), but was not between those on the NG and the ED images. Thus, the change in the %uptake on the NG image was more related to those on the ES image which is more affected by the change in regional wall motion than those on the ED image which reflects improved myocardial perfusion. These results suggest that ECG-gated myocardial 99mTc-MIBI SPECT is more useful to assess the serial change in myocardial perfusion and contraction than the conventional non-gated SPECT in the follow-up study of patients with AMI.

Arrhythmogenic right ventricular cardiomyopathy underlies syndrome of right bundle branch block, ST-segment elevation, and sudden death

Right ventricular morphologic and/or histologic abnormalities were present in 5 of 6 Japanese men with the Brugada syndrome. Results indicate that arrhythmogenic right ventricular cardiomyopathy may underlie the cardiac manifestations in the Brugada syndrome.

Growth curve of ruptured aortic aneurysm

OBJECTIVE

We hypothesized that the aortic aneurysm might grow biexponentially. The object of this study was to determine the biexponential growth curve of aortic aneurysm.

DESIGN

A fifteen-year retrospective review of CT images of aortic aneurysm.

SETTING

Major cardiovascular referral center.

PATIENTS

Patients with true aortic aneurysm who were followed up with CT and performed CT at their aneurysmal ruptures.

MEASURES

The largest short-axial diameters of the outer contour of the aneurysms were measured. Aortic aneurysmal diameters were normalized by those at ruptures, and the plots were fitted to the biexponential curve.

RESULTS

Eight patients out of 1481 had been followed up with CT scans. In regression analysis, the values fit well to the biexponential equation: d(t) = 0.8345 exp (0.0052 t) + 0.1653 exp (0.8275 t), r = 0.934 where d(t) is the normalized diameter, and t is months before rupture. The first part of the equation mainly expresses the slow growth, and the second expresses the rapid growth shortly before rupture.

CONCLUSIONS

Aortic aneurysm began to grow faster at about three months before rupture. It is important to find out the point that the growth of aortic aneurysm changes its rate faster than before, and once the point is observed, elective repair should be considered.

Subtraction CT angiography with controlled-orbit helical scanning for detection of intracranial aneurysms

PURPOSE

Our goal was to evaluate the utility of subtraction three-dimensional CT angiography for the detection of intracranial aneurysms.

METHODS

Thirty-six patients with intracranial aneurysms were examined using newly devised controlled-orbit helical scanning and conventional angiography. Three-dimensional CT angiograms and subtraction 3-D CT angiograms were compared with conventional angiograms for their characterization of intracranial aneurysms.

RESULTS

Fifty aneurysms were depicted on conventional angiograms, of which 48 (96%) were seen on the 3-D CT angiograms. Three-dimensional CT angiography was superior or equivalent to conventional angiography for depicting the shape, direction, and location of 33 (66%) of 50 aneurysms; however, it was often less useful than conventional angiography in delineating intracranial aneurysms adjacent to bone. Subtraction 3-D CT angiograms were obtained in 32 patients with a total of 46 aneurysms (in four cases, aneurysms were not depicted owing to excessive motion artifacts), and were superior or equivalent to conventional angiograms in all 46 cases.

CONCLUSIONS

Subtraction 3-D CT angiography with the use of controlled-orbit helical scanning is effective in the detection of intracranial aneurysms.

Plasma brain natriuretic peptide levels increase in proportion to the extent of right ventricular dysfunction in pulmonary hypertension

OBJECTIVES

This study sought to investigate the influence of right ventricular (RV) hemodynamic variables and function on the secretion of brain natriuretic peptide (BNP) in patients with isolated RV overload.

BACKGROUND

Plasma BNP is known to increase in proportion to the degree of left ventricular (LV) overload. However, whether BNP secretion is also regulated in the presence of RV overload remains unknown.

METHODS

Plasma BNP and atrial natriuretic peptide (ANP) levels in the pulmonary artery were measured in 44 patients with RV overload: 18 with RV volume overload (RVVO) due to atrial septal defect and 26 with RV pressure overload (RVPO) due to primary or thromboembolic pulmonary hypertension. Right heart catheterization was performed in all patients. RV and LV ejection fraction, myocardial mass and volume of the four chambers were determined by using electron beam computed tomography.

RESULTS

Although both plasma BNP and ANP levels were significantly elevated in patients with RV overload compared with values in control subjects, plasma BNP and the BNP/ANP ratio were significantly higher in patients with RVPO than with RVVO (BNP 294 +/- 72 vs. 48 +/- 14 pg/ml; BNP/ANP 1.6 +/- 0.2 vs. 0.8 +/- 0.2, both p < 0.05). Plasma BNP correlated positively with mean pulmonary artery pressure (r = 0.73), total pulmonary resistance (r = 0.79), mean right atrial pressure (r = 0.79), RV end-diastolic pressure (r = 0.76) and RV myocardial mass (r = 0.71); it correlated negatively with cardiac output (r = -0.33) and RV ejection fraction (r = -0.71). Plasma BNP significantly decreased from 315 +/- 120 to 144 +/- 54 pg/ml with long-term vasodilator therapy (total pulmonary resistance decreased from 23 +/- 4 to 15 +/- 3 Wood U).

CONCLUSIONS

Plasma BNP increases in proportion to the extent of RV dysfunction in pulmonary hypertension.

[Evaluation of the automatic quantification of left ventricular function using ECG gated 99mTc-MIBI myocardial SPECT]

We studied the accuracy of left ventricular (LV) volumes and ejection fraction (EF) derived from ECG gated 99mTc-sestamibi myocardial perfusion SPECT (G-SPECT) and the software for automatic data analysis (QGS program described by Germano G et al.). G-SPECT was performed in 29 patients with various cardiac diseases. LV end-diastolic and end-systolic volumes (LVEDV and LVESV), and LVEF determined by QGS program were compared to those by Simpson method in biplane left ventriculography (LVG). Interobserver reproducibility in measuring the G-SPECT parameters was excellent (LVEDV: r = 0.99, LVESV: r = 0.99, LVEF: r = 0.97). There was a good correlation between the values obtained from G-SPECT and LVG (LVEDV: r = 0.92, LVESV: r = 0.94, LVEF: r = 0.85), but G-SPECT tended to underestimate LVEDV and LVEF. In 17 patients with moderate to severe myocardial perfusion defects selected from the subjects, the correlation was maintained fairly high (LVEDV: r = 0.90, LVESV: r = 0.92, LVEF: r = 0.77). In conclusion, QGS program provides high accuracy and reproducibility in determining LV volumes and LVEF from G-SPECT.

Noninvasive identification of left ventricular involvements in arrhythmogenic right ventricular dysplasia: comparison of 123I-MIBG, 201TlCl, magnetic resonance imaging and ultrafast computed tomography

We examined the feasibility of myocardial 123I-MIBG, 201TlCl, magnetic resonance imaging (MRI) and ultrafast computed tomography (UFCT) for the early detection of left ventricular involvements in 15 patients with arrhythmogenic right ventricular dysplasia (ARVD). Radionuclide ventriculography (RNV) and myocardial imaging with 123I-MIBG, 201TlCl, MRI and UFCT were performed in all 15 patients and in 10 normal subjects. The patients' scans were visually interpreted by two nuclear medicine physicians taking into consideration the extent score (ES) and severity score (SS) calculated by using the bull's-eye view in relation to normal data derived from the normal subjects. The left ventricular ejection fraction (LVEF) was measured by RNV. Fourteen (93%) patients showed regional 123I-MIBG defects, while 12 (80%) patients showed regional 201TlCl defects. The ES and SS were higher in 123I-MIBG than 201TlCl (ES: 31.5 +/- 18.5 vs. 17.5 +/- 18.2, p < 0.01, SS: 34.8 +/- 42.2 vs. 16.9 +/- 37.5, p < 0.01). Abnormal UFCT and MRI findings suggesting fatty involvements of the LV myocardium were demonstrated in 7 patients (Group B), while 7 patients showed regional 123I-MIBG defects without abnormal UFCT and MRI findings (Group A). 123I-MIBG was significantly more sensitive than UFCT and MRI (p < 0.05), although one patient, an exception, showed abnormal UFCT findings for the apex of the LV myocardium without abnormal 123I-MIBG and MRI findings. The LVEF, as a measure of LV systolic function, was better preserved in Group A than in Group B (59.3 +/- 3.6 vs. 45.8 +/- 5.8, p < 0.01). The present findings indicated that myocardial imaging with 123I-MIBG sensitively detects myocardial damage in patients with ARVD in the early stage when cardiac systolic function is still preserved.

Popliteal artery entrapment syndrome: aberrant origin of gastrocnemius muscle shown by 3D CT

PURPOSE

The purpose of this report is to evaluate the usefulness of 3D CT in the diagnosis of popliteal artery entrapment (PAE) syndrome.

METHOD

Three patients (three men, 22-70 years old) with suspected PAE syndrome were examined using helical CT. 3D images were reconstructed to evaluate the relationship between the popliteal artery and the gastrocnemius muscle. 3D arteriograms were simultaneously reconstructed.

RESULTS

One patient had unilateral type 3 PAE syndrome. Bilateral PAE syndrome was seen in the other two cases: One had bilateral type 2 anomalies and the other had type 3 on the left and type 2 on the right. In all three cases the anomalous origin of the medial head of the gastrocnemius muscle and its relationship to popliteal artery were clearly visualized by 3D CT. In addition, CT arteriography could detect occlusion, deviation, or stenosis of the popliteal arteries.

CONCLUSION

3D CT is useful in the diagnosis and management of PAE syndrome.

Aortic arch operation using selective cerebral perfusion for nondissecting thoracic aneurysm

BACKGROUND

Risks of increasing mortality and disability in aortic arch operations using the selective cerebral perfusion method for nondissecting aneurysm have not yet been determined. A multicenter, retrospective study was employed.

METHODS

The subjects were 143 patients who were admitted to one of the nine cardiovascular centers between January 1988 and December 1993, including 15 with ruptured aneurysm. A graft replacement of the transverse aortic arch or distal arch was performed in 80 patients, extensive aortic reconstruction comprising simultaneous replacement of the ascending or descending thoracic aorta (or both) in 46, and patch repair of involved arch in 17. The mean postoperative follow-up period was 19 months.

RESULTS

Hospital mortality was 36/143 patients (25.2%). Univariate analysis revealed that age of 70 years or more, ruptured aneurysm, and renal dysfunction affected hospital mortality. Neurologic deficits were noted in 15 patients (10.5%). Reoperation was performed in 13 patients for residual distal aneurysm or false aneurysm. Late death occurred in 10 patients and were due to vascular complications in 6. Multivariate analysis confirmed that aneurysmal rupture and renal dysfunction were independent predictors for vascular death including hospital mortality.

CONCLUSIONS

The present study confirmed that age, aneurysmal rupture, and renal dysfunction were significant predictors for mortality and disability in the aortic arch operation using selective cerebral perfusion for nondissecting thoracic aneurysm.

Operation for nondissecting aneurysm in the descending thoracic aorta

BACKGROUND

Little is known about the risks of mortality and morbidity after descending thoracic aortic aneurysm repair using left heart bypass and temporary arterioarterial bypass.

METHODS

A multicenter, retrospective study was performed on 120 patients who were admitted to one of nine cardiovascular centers between January 1988 and December 1993 and underwent operation for nondissecting thoracic aortic aneurysm. The present series included 10 patients with ruptured aneurysm. Graft replacement was performed in 95 patients, patch repair in 22, and suture of the ruptured aorta in 3. Venoarterial bypass was used in 45 patients, left heart bypass in 56, and temporary arterioarterial bypass in 19 as circulatory support. The mean postoperative follow-up period was 30 +/- 21 months.

RESULTS

Hospital mortality occurred in 7 patients (5.8%). Univariate analysis revealed that only aneurysmal rupture was related to hospital mortality. Brain or cord injury was observed in 4. Of nine deaths that occurred after discharge, five were related to aneurysm and two were due to vascular event. No significant difference was noticed in probability of survival according to the circulatory supporting method. Only aneurysmal rupture affected probability of survival. Multivariate analysis revealed that aneurysmal rupture was the only independent predictor for vascular death including hospital mortality.

CONCLUSIONS

The present study confirms that aneurysmal rupture is a significant predictor for mortality and morbidity in aortic operations for nondissecting descending thoracic aneurysm, and that a similarly good outcome would be expected when using left heart bypass, temporary arterioarterial bypass, or venoarterial bypass.

[A case of DeBakey type IIIb acute aortic dissection extending through an atherosclerotic abdominal aortic aneurysm]

We report a case of DeBakey type IIIb aortic dissection which extended distally through a pre-existing fusiform abdominal aortic aneurysm. The concurrence of aortic dissection and atherosclerotic aortic aneurysm is unusual. Among the various types of this concurrence, aortic dissection extending through a pre-existing aneurysm is rare.

[Recent progress of diagnostic imaging for aortic dissection]

After advent newly developed imaging modalities, diagnosis for aortic dissection had been extremely easier as compared with at the time when we had diagnosed this lesion solely by angiography. Characteristics of intra-arterial digital subtraction angiography (DSA), computed tomography (CT), magnetic resonance imaging (MRI) and transesophageal echocardiography (TEE) for this lesion was reviewed. In particular, we described how much three dimensional reconstructed CT using ultrafast computed tomography (electron beam tomography: EBT) and helical computed tomography (HCT) contribute to diagnosis for this disease. Furthermore, it was commented upon how to diagnose for acute aortic dissection with modern diagnostic tools based on our praxis.

Successful retrieval of unexpanded Palmaz-Schatz stent from left main coronary artery

A 64-year-old patient with silent myocardial ischemia after anterior myocardial infarction was treated with directional coronary atherectomy, balloon angioplasty, and placement of Palmaz-Schatz stent. An unexpanded Palmaz-Schatz stent was retained in the left main coronary artery and was treated successfully with a nitinol goose-neck snare. After this procedure, another Palmaz-Schatz stent was successfully implanted without any complications.

Usefulness of electron-beam computed tomography in arrhythmogenic right ventricular dysplasia. Relationship to electrophysiological abnormalities and left ventricular involvement

BACKGROUND

Electron-beam computed tomography (CT) may be useful for detecting myocardial fat infiltration and diagnosing arrhythmogenic right ventricular dysplasia (ARVD). There are several characteristic electron-beam CT findings of ARVD. However, the incidence, their relation to electrophysiological abnormalities, and the usefulness of electron-beam CT for evaluating left ventricular involvement are unknown. This study aimed to clarify these issues.

METHODS AND RESULTS

Electron-beam CT was performed in 14 patients with ARVD (ARVD group), 16 age- and sex-matched patients with right ventricular enlargement and/or dysfunction without ARVD (RV enlargement group), and 13 control subjects (control group). The incidences of abnormal electron-beam CT findings in the three groups were examined. Furthermore, we examined the endocardial fat-infiltrated areas detected by electron-beam CT (CT-A) and electrophysiologically abnormal areas detected in the mapping electrophysiology study (EPS-A) and compared the relationship between them in the ARVD group. (1) The frequencies of abundant epicardial adipose tissue, low-attenuation trabeculations, scalloping of the right ventricular free wall, and intramyocardial fat deposits were 86%, 71%, 79%, and 50%, respectively, in the ARVD group, whereas these findings were not observed in the RV enlargement and control groups. (2) Three ARVD patients (21%) had adipose tissue involvement of the left ventricle. (3) The relationship between CT-A and EPS-A was as follows: CT-A > EPS-A, 71%; CT-A = EPS-A, 14%; and EPS-A only, 14%.

CONCLUSIONS

Characteristic electron-beam CT findings are frequently observed only in patients with ARVD. Electron-beam CT is useful for evaluating for left ventricular involvement and can estimate EPS-A.

[Significance of 123I-metaiodobenzylguanidine SPECT for detecting left ventricular involvement in patients with arrhythmogenic right ventricular dysplasia]

The right ventricle being primarily involved in ARVD, recent reports indicate the presence of histological and functional abnormalities in the left ventricle for some patients with ARVD. The aim of this study was to evaluate the significance of myocardial sympathetic dysfunction as an early sign of left ventricular (LV) involvement by 123I-MIBG (MIBG) SPECT and to compare the findings with those of 201TlCl (Tl) SPECT, radionuclide left ventriculography, ultrafast computed tomography (UFCT), magnetic resonance imaging (MRI) and echo-cardiography in 10 patients (pts) with ARVD. MIBG defects in LV regions were detected in 9 pts. Seven of the 9 pts showed MIBG defects in LV regions adjacent to RV. The subjects were divided into 2 groups based on left ventriculography, 5 with normal LVEF (> 55%) and 5 with reduced LVEF. In the normal LVEF group, 4 pts showed MIBG defects and 2 pts showed TI defects, and MIBG defects were larger than TI defects (ES: 14 +/- 6 vs. 5 +/- 7, p <0.05). In reduced LVEF group, all of 5 pts showed MIBG and TI defects, and MIBG defects were larger than TI defects (ES: 42 +/- 12 vs. 25 +/- 3, p <0.05). In comparison with normal LVEF group, reduced LVEF group showed larger and more severe MIBG defects (ES: 42 +/- 12 vs. 14 +/- 6, p <0.01, SS: 44 +/- 31 vs. 8 +/- 7, p <0.05). UFCT and MRI showed abnormal findings indicating LV fatty infiltration in only 3 of reduced LVEF group. Thus, MIBG showed abnormal distributions in the left ventricle with the highest frequency in all these modalities. These results suggest that MIBG SPECT provides a sensitive marker for detecting LV involvement in ARVD. Also, the extent of MIBG distribution abnormalities is helpful in assessing the severity of left ventricular involvement in patients with ARVD.

Intracranial calcification on gradient-echo phase image: depiction of diamagnetic susceptibility

PURPOSE

To differentiate calcification from hemorrhage on the basis of susceptibility at magnetic resonance imaging.

MATERIALS AND METHODS

Gradient-recalled echo (GRE) phase imaging was performed at 1.5 T in 101 calcified areas (15 in the basal ganglia, 86 out of the basal ganglia) and 39 uncalcified locations (13 choroid plexus and pineal glands, 26 old hemorrhages). Experiments with a small lead particle and a numerical simulation were also performed.

RESULTS

The majority of calcifications outside the basal ganglia (n = 63) revealed a phase shift that represents diamagnetic susceptibility and was similar to the phase shift in the lead particle and to the calculated phase shift for a diamagnetic sphere. All hemorrhages and almost all calcified basal ganglia revealed a phase shift that represents paramagnetic susceptibility. All uncalcified choroid plexus and pineal glands revealed no obvious phase shift. Any location without calcification did not reveal the diamagnetic phase shift.

CONCLUSION

GRE phase imaging differentiated paramagnetic from diamagnetic susceptibility, which was specific for calcification.

[Usefulness of palliative care for the patients with recurrent gastric cancer by home-IVH]

Depending upon the type of cancer involved, the period of the end stage varies greatly, and with it decreases the quality of life (QOL). In gastric cancer, for example, the terminal stage is usually short and the QOL diminishes abruptly. Thus, it takes time keeping this decrease in QOL to minimum, despite the complications, so that the patient's last days will be even somewhat more acceptable. Improvement in QOL for the patient who cannot eat due to recurrent gastric cancer can be effectively achieved by alleviation through IVH. With this in mind, the conditions consonant with the application of home IVH are as follows: 1) The patient's pain can be kept under control at home. 2) The patient wishes to remain. 3)There is sufficient human support at home. The caretakers in the family, and especially the key person(s) must exert much effort and labor and they need rest as well. Home medical care in the terminal stage presupposes a social environment involving day care, short stay, and hospice nursing facilities of all kinds. At present, public services of this kind differ with the community, much remains uninformed to public, and clinic-hospital networking will be needed more than ever. In this difficult situation, the home-care medical services provided by the private sector are effective. These services are only for the short term, of course, and there will be a financial problem. Various measures (tax deduction, public assistance) must be considered to support the patients and caretakers.

Scintigraphic assessment of silent myocardial ischaemia after early infarction using myocardial SPET imaging with 201Tl and 123I-MIBG

To test the hypothesis that myocardial sympathetic denervation reflects silent myocardial ischaemia early after infarction, 12 patients with myocardial infarction but without post-infarction angina pectoris underwent single photon emission tomography (SPET) at rest with 201Tl and 123I-metaiodobenzylguanidine (MIBG) shortly after and 3 months after infarction. Short-axis SPET images at the basal, mid-ventricular and apical portions of the left ventricle were selected, and each short-axis image was divided into eight segments. Tracer uptake in each of the 24 segments was scored using a 4-point scale. The total score in each segment was calculated as the defect score for each image, and the difference between the total defect score for the 201Tl and 123I-MIBG images was calculated as the delta defect score. All 12 patients underwent exercise stress 201Tl scintigraphy 1 month after infarction, and they were divided into two groups: those patients with (Group A, n = 7) and those patients without (Group B, n = 5) transient perfusion defects in the peri-infarcted region without chest pain. For the 123I-MIBG defect score, a marked reduction at 3 months was observed in Group A (24 +/- 12 vs 13 +/- 6; P < 0.01), whereas the defect score remained unchanged in Group B (25 +/- 7 vs 23 +/- 8; N.S.). The delta defect score was significantly reduced in Group A (10 +/- 5 vs 6 +/- 4; P < 0.05), whereas it remained unchanged in Group B. The 123I-MIBG defect score early after infarction was higher than the exercise-induced 201Tl defect score (24 +/- 12 vs 20 +/- 9; P < 0.01), whereas at 3 months post-infarction it was lower than the exercise-induced 201Tl defect score (13 +/- 6 vs 20 +/- 9; P < 0.05). Moreover, effort chest pain during daily activities was noted in 5 of the 7 (71%) patients in Group A within 3 months post-infarction. The results of this study suggest that viable but denervated myocardium (mismatched 123I-MIBG defects) is present in peri-infarcted regions, and that myocardial sensory nervous disturbance, which may co-exist with sympathetic nervous denervation, may induce silent myocardial ischaemia in patients with myocardial infarction.

[Detection of myocardial 123I-BMIPP distribution abnormality in patients with ischemic heart disease based on normal data file in bull's-eye polar map]

Visual interpretation of 123I-BMIPP (BMIPP) myocardial images has difficulties in detecting mild reduction in tracer uptake. We studied the significance of the objective assessment of myocardial BMIPP maldistributions at rest by using a Bull's-eye map and its normal data file for detecting ischemic heart disease. Twenty nine patients, 15 with prior myocardial infarction and 14 with effort angina were studied. The initial 15-min BMIPP image was evaluated by visual analysis and by generating the extent Bull's-eye map which exhibits regions with reduced % uptake under mean-2SD of 10 normal controls. The sensitivity for determining coronary lesions in non-infarcted myocardial regions with the extent map was superior to that with visual analysis (67% vs. 33%). In the regions supplied by the stenotic coronary artery, those which showed visually negative but positive in the map and which showed positive in both had higher incidence of wall motion abnormalities and severe coronary stenosis than those with normal findings in both. These results suggest that the objective assessment based on the normal data file in a Bull's-eye polar map is clinically important for improving the limitation of the visual interpretation in 123I-BMIPP imaging.

Significance of dipyridamole loading in ultrafast x-ray computed tomography for detection of myocardial ischemia. A study in patients with Kawasaki disease

BACKGROUND AND RATIONALE

To examine the significance of dipyridamole loading as a stress in ultrafast computed tomography (CT) to improve the detection of left ventricular myocardial ischemia.

METHODS

Thirty-eight patients with coronary arterial involvement of Kawasaki disease and 18 control subjects received cardiac ultrafast CT with intravenous long-bolus iodinated contrast injection; dipyridamole was loaded in 40 examinations. Early (first-pass) and late (4 minutes) M/Ls (ratio of postcontrast incremental increases in the left ventricular myocardial [M] and luminal [L] CT number) were analyzed.

RESULTS

Dipyridamole induced a prominent increase in early M/L of the normal myocardium in control subjects (no loading: 26.8%, dipyridamole: 39.2%; P < 0.001) with small influence on late M/Ls. In ischemic or infarcted myocardium in Kawasaki disease, dipyridamole early M/Ls (20.4%, 16.0%) and late M/Ls showed no difference from corresponding values without loading. Using early M/L with dipyridamole, sensitivity and specificity for detection of ischemic abnormalities were 89% and 100%, respectively.

CONCLUSIONS

Dipyridamole-loaded first-pass contrast ultrafast CT was proven to have excellent detectability for myocardial ischemia comparable with stress thallium scintigraphy.

[Characteristics of regional sympathetic dysfunction in acutely ischemic myocardium assessed by 123I-metaiodobenzylguanidine imaging: impairment of myocardial norepinephrine uptake or retention]

To characterize regional cardiac sympathetic dysfunction due to myocardial ischemia, we examined 123I-metaiodobenzylguanidine (MIBG) myocardial distribution of initial 15-min and 4-hr delayed SPECT images in 14 patients with recent myocardial infarction (MI), 25 patients with vasospastic angina which was angiographically proven with elgonovine maleate (Gp VSAP) and 16 patients with chest pain syndrome and normal CAG findings (GpCP). In those with MI, the study was serially done at 2 weeks after (Gp MI-1) and at 3 months after the onset of MI (Gp MI-2). We estimated regional tracer uptake in 20 segments of tomographic images by using a 4-point scoring system (0 = normal, 1 = mild, 2 = moderate, 3 = severe reduction) and calculated the total defect score (IDS). In all patients with MI, the area of reduced MIBG uptake was more extensive than the 201Tl perfusion defect in the acute stage (Gp MI-1) indicating the presence of viable but denervated myocardial tissue. Also, the MIBG defect was persistently observed from initial (TDS: 24 +/- 13) to delayed imaging (TDS: 26 +/- 12). However, in the chronic stage (Gp MI-2), the initial MIBG uptake improved (TDS: 18 +/- 9) but the delayed uptake remained almost the same (TDS: 22 +/- 10) indicating high washout of MIBG from the ischemic myocardium. Fourteen in Gp VSAP and 14 in Gp CP showed the regional MIBG defect in the delayed image more extensively than in the initial image indicating high washout of MIBG in the involved myocardial regions. These results suggest that neuronal uptake of MIBG is impaired in the acute stage of MI although neuronal retention of MIBG is predominantly impaired in the chronic stage of MI or in Gps VSAP and CP.

Perfusion lung scanning before and after percutaneous transvenous mitral commissurotomy--early estimation of lung congestion relief

Percutaneous transvenous mitral commissurotomy (PTMC) has recently been used to treat mitral stenosis. The aim of this study was to evaluate the usefulness of radionuclide perfusion lung scanning in assessing the effect of PTMC on the relief of lung congestion. We studied 30 patients (7 males and 23 females, mean age 55 years). Perfusion lung scannings were performed within 1 week before and after PTMC. We calculated the ratio of activity in the upper quarter to that in the lower quarter of the right lung (U/L) as an index of lung congestion. After PTMC, the mean mitral valve area increased from 1.1 +/- 0.3 to 1.9 +/- 0.4 cm2, the mean left atrial pressure decreased from 14.8 +/- 6.3 to 9.1 +/- 3.5 mmHg, the mean pulmonary artery pressure decreased from 22.7 +/- 8.6 to 17.4 +/- 6.3 mmHg, and the U/L ratio decreased significantly from 0.89 +/- 0.40 to 0.68 +/- 0.24 (p < 0.0001). The U/L ratio showed greater improvement (4.5%) in patients whose NYHA class improved (n = 19) than in those whose NYHA class did not improve after PTMC. The U/L ratio was closely related to mitral valve area, and left atrial and pulmonary artery pressures. The change in the U/L ration before and after PTMC also reflected symptomatic improvement. In conclusion, U/L ratios obtained from perfusion lung scannings before and after PTMC reflect mitral valve area and pressures, and can be used to assess lung congestion relief after PTMC.

I-123 iodoamphetamine lung scanning in patients with ventilation-perfusion mismatching

I-123 IMP is a nonparticulate agent and becomes trapped by endothelial membranes in the pulmonary capillaries. Using I-123 IMP, the authors studied six patients with ventilation-perfusion mismatch. Three of six patients had pulmonary thromboembolism, and three had pulmonary hypertension. In comparison with conventional perfusion lung scanning using Tc-99m MAA, defect sizes visualized by I-123 IMP were smaller in all patients. I-123 iodoamphetamine is a useful agent for assessing the perfusion of pulmonary arterial microvasculature which Tc-99m MAA fails to penetrate.

Predicting the growth of aortic aneurysms: a comparison of linear vs exponential models

The aim of the present study was to determine whether the growth curve of aortic aneurysms had a predictable pattern, specifically whether the growth pattern was better defined by a linear or exponential rate of growth. A twelve-year retrospective review was undertaken. The authors studied 59 patients with aortic aneurysm who have been followed up nonoperatively for more than three years with sequential computed tomographic (CT) scans. There was a total of 74 aortic aneurysms (thoracic aortic aneurysm [TAA]: 30, abdominal aortic aneurysm [AAA]: 44). The diameter of the aortic aneurysm was normalized by dividing by the initial diameter. Exponential (y = A exp [Bt]) and linear (y = C+Dt) regression curves of growth of aneurysmal diameters were calculated, where y is the normalized diameter and t is the time after first CT examination in months. In regression analysis, the values fit well to the exponential growth curves, giving high regression coefficients. Exponential regression equations of TAA and AAA were y = 1.0192 exp (0.0032t), r = 0.720 and y = 1.0129 exp (0.0045t), r = 0.789, respectively. The results in favor of the exponential curve analysis were slightly higher than those favoring the linear curve. This is the first study that showed the growth curves of aortic aneurysms. Aortic aneurysms may grow exponentially rather than linearly with time, and the growth curves might be useful for estimating the natural history or predicting the timing of surgery.

Sequential MR signal change of the thrombus in the false lumen of thrombosed aortic dissection

The evolution of thrombus in the false lumen was investigated in 14 patients with thrombosed aortic dissection, by reviewing the findings acquired at a total of 21 magnetic resonance imaging (MRI) examinations performed between 2 and 146 days after the onset. On electrocardiographic gated 1.5-Tesla MRI, T1-(TR/TE = 860 +/- 190 ms/17-40 ms) and T2-(TR/TE = 1620 +/- 240 ms/70-80 ms) weighted spin echo and gradient echo images were obtained, and the signal intensity of the thrombus on these images was evaluated independently by two observers. The density of the thrombus was also evaluated using computed tomography (CT) images obtained at a total of 54 examinations. On both T1- and T2-weighted images, the thrombus showed signal iso- or hypointensity compared to that of skeletal muscle during the first several days after the onset and, thereafter, showed signal intensity similar to that of fat tissue. It is suggested that the low signal intensity of the thrombus observed during the initial period after the onset was caused by the presence of deoxyhemoglobin and the high intensity observed thereafter was caused by methemoglobin. Focal discrepancy of the signal intensities within two parts of the lumen on spin echo images was observed in 7 patients, and a low-intensity layer on the surface of the thrombus inside the false lumen was observed on gradient echo images in 5 of these 7 patients. This characteristic MR signal change of the thrombus in the false lumen of thrombosed aortic dissection provides useful information concerning the age of the thrombus and in the differential diagnosis of the thrombus from a mural thrombus of aortic aneurysm.

[Feasibility of the left ventricular volume measurement by acoustic quantification method: comparison with ultrafast computed tomography]

Acoustic quantification (AQ: the real-time automated boundary detection system) allows instantaneous measurement of cardiac chamber volumes. The feasibility of this method was evaluated by comparing the left ventricular (LV) volumes obtained with AQ to those derived from ultrafast computed tomography (UFCT), which enables accurate measurements of LV volumes even in the presence of LV asynergy, in 23 patients (8 with ischemic heart disease, 5 with cardiomyopathy, 3 with valvular heart disease). Both LV end-diastolic and end-systolic volumes obtained with the AQ method were in good agreement with those obtained with UFCT (y = 1.04 x - 16.9, r = 0.95; y = 0.87x + 15.7, r = 0.91; respectively). AQ was reliable even in the presence of LV asynergy. Interobserver variability for the AQ measurement was 10.2%. AQ provides a new, clinically useful method for real-time accurate estimation of the left ventricular volume.

Clinical studies on the sites of production and clearance of circulating adrenomedullin in human subjects

Adrenomedullin is a novel hypotensive peptide, newly discovered in pheochromocytoma. Because immunoreactive adrenomedullin is present in human plasma, adrenomedullin may play a role in regulating blood pressure. A recent report showed that human adrenomedullin mRNA is expressed not only in pheochromocytoma but also in the normal adrenal medulla, kidney, lung, and ventricle. However, whether or not these organs actually release adrenomedullin into the circulation remains unknown. To investigate the sites of production and degradation of adrenomedullin in human subjects, we obtained blood samples from various sites and measured immunoreactive adrenomedullin concentrations. In study 1, blood samples were obtained from the infrarenal inferior vena cava, suprarenal inferior vena cava, superior vena cava, right atrium, right ventricle, pulmonary artery, pulmonary capillary, left ventricle, and aorta during cardiac catheterization in 15 patients with ischemic heart disease (67 +/- 10 years). In study 2, blood samples were taken from the infrarenal inferior vena cava, suprarenal inferior vena cava, right and left renal veins, and left adrenal vein in 5 hypertensive patients (42 +/- 14 years) suspected of having renovascular hypertension. In study 3, peripheral venous blood samples were obtained in 2 patients (males, 45 and 36 years old) with pheochromocytoma at rest and during hypertensive attacks. Plasma adrenomedullin concentrations were measured by a newly developed radioimmunoassay. In study 1, there were no significant differences in plasma adrenomedullin concentrations in various sites of the right-side circulation. There was no step-up of plasma adrenomedullin levels in the coronary sinus. However, the plasma concentration of adrenomedullin in aorta was slightly but significantly lower than in pulmonary artery.(ABSTRACT TRUNCATED AT 250 WORDS)

[A case of inflammatory abdominal aortic aneurysm with associated inferior vena caval and bilateral ureteral obstruction]

One year ago, a 48-year-old man complained of dyspnea, and was diagnosed as mitral valve regurgitation and aortic dissection. He underwent mitral valve replacement and aortic arch grafting. He was also pointed out to have an inflammatory aortic aneurysm (IAAA) in the infrarenal abdominal aorta, but did not undergo surgery. At this admission, he had lumbago and low grade fever probably due to deterioration of the IAAA. On the preoperative radionuclide studies, inferior vena caval obstruction and bilateral ureteral obstruction or severe stenosis were demonstrated by 99mTc-MAA venography and 123I-OIH renogram, respectively. 67Ga scan showed faint abnormal accumulation at the IAAA. He underwent surgery. IAAA had a thick wall in white and hard fibrotic tissue adhered closely to duodenum, jejunum, inferior vena cava and bilateral ureters. After surgery, his renal function was improved. In this case, radionuclide studies were useful for detecting the inferior vena caval obstruction, assessing renal function and inflammatory activity.

Myocardial involvement in patients with sarcoidosis. An analysis of 75 patients

The authors studied 75 nonselected patients (30 men and 45 women; mean age 48 years) with sarcoidosis retrospectively to assess the applicability of nuclear examinations for detecting myocardial involvement. All patients were studied with Tl-201 myocardial perfusion scan (TMPS), Ga-67 myocardial scan (GMS), and left ventricular ejection fraction (LVEF) using ECG-gated radionuclide ventriculography. The positive GMS group had a significantly higher occurrence of abnormality on TMPS (100%) than the negative GMS group (41%). Patients with TMPS abnormality and positive GMS showed significantly lower LVEF (36.3%) than those of normal perfusion or negative GMS. When LVEF decreased, occurrences of TMPS abnormality and positive GMS increased. The authors demonstrate that in patients with sarcoidosis LVEF was closely related to TMPS and GMS, and LVEF reflected the progression of sarcoid heart disease and can be considered a reliable indicator of cardiac function. Patients with sarcoidosis with TMPS abnormality and positive GMS should be thought to have myocardial sarcoidosis and their cardiac functions can be assessed by ECG-gated radionuclide ventriculography, while the remaining patients should be examined with TMPS and GMS periodically for detection of myocardial involvement.

Myocardial damage in patients with dilated cardiomyopathy: CT evaluation

OBJECTIVE

The purpose of this study was to evaluate myocardial damage in patients with dilated cardiomyopathy (DCM) by ultrafast CT (UFCT) and estimate the improvement of DCM.

MATERIALS AND METHODS

Seventeen patients with DCM were examined with UFCT, cardiac catheterization, left ventriculography (LVG) with manometry, and thallium myocardial scintigraphy (SCINTI). The findings of each examination were compared with each other. Especially, UFCT findings were compared with LV function.

RESULTS

Late enhancement, focal wall thinning, and fatty component were detected by UFCT as focal abnormal findings. Left ventricular segments with these findings on UFCT correlated well with asynergy on LVG (p < 0.01) and perfusion defects on SCINTI (p < 0.05). Patients with these findings on UFCT showed significantly lower LV ejection fractions (p < 0.05), higher LV end-diastolic pressure (p < 0.05), and a higher incidence of ventricular tachycardia (p < 0.05).

CONCLUSION

The focal myocardial abnormalities in DCM patients were well depicted with UFCT. Ultrafast CT was useful in estimating the severity of DCM and classifying the DCM patients.

Quantitative evaluation of mitral regurgitation with ultrafast CT

OBJECTIVE

To quantify cardiac valvular regurgitation, ultrafast CT was performed in 44 patients (including 27 patients with mitral regurgitation).

MATERIALS AND METHODS

Stroke volume of the left ventricle was calculated by modified Simpson's rule with cine mode scanning of ultrafast CT, and ventricular output was measured as the product of stroke volume and heart rate. Cardiac output was calculated in the ascending aorta by the formula of the indicator dilution method with flow mode scanning of ultrafast CT. The difference between the left ventricular output and cardiac output was defined as "mitral regurgitant volume." Left ventriculography was also performed at the same time, to estimate the degree of mitral regurgitation according to Sellers' classification.

RESULTS

There was significant correlation between regurgitant fraction, standardized regurgitant volume, and grade of mitral regurgitation estimated by left ventriculography.

CONCLUSION

CT can measure mitral regurgitant volume by the combination of volumetry and indicator dilution method.

Diastolic suction in the human ventricle: observation during balloon mitral valvuloplasty with a single balloon

Diastolic suction has been demonstrated experimentally as a ventricular negative pressure when the ventricle is allowed to relax completely in the absence of filling, but it has not been extensively studied in the in vivo human heart. In balloon mitral valvuloplasty with a single balloon, the mitral orifice is occluded and inflow is considered to be completely obstructed during a balloon inflation. To demonstrate diastolic suction in the human ventricle, we measured left ventricular pressure during valvuloplasty with a high-fidelity catheter tip manometer in 17 patients. Left ventricular pressure fell below zero during a balloon inflation in all patients (-2 to -12 mm Hg). The peak negative diastolic pressure showed significant correlations with end-systolic volume index (r = 0.53, p = 0.03) and with the ejection fraction (r = 0.80, p = 0.0001). Thus diastolic suction was demonstrated in the human beating heart, and the sucking effect was potent in the heart with small end-systolic volume and high-ejection fraction.

[Detectability of diagonal branch disease with other branch lesions by 201TlCl exercised myocardial scintigraphy]

The detectability of coronary diagonal (Dx) branch disease in 24 patients (16 with myocardial infarction, 8 with angina pectoris; mean age of 56) with other branch (left anterior descending branch [LAD], left circumferential branch [LCX], or right coronary artery [RCA]) diseases was reviewed with 201TlCl exercised myocardial planar and SPECT images. In Dx branch disease with LAD #7 lesion (n = 10), Dx perfusion abnormality was detected in planar and SPECT images in 3 (30%) and 8 patients (80%), respectively. In Dx branch disease with LCX lesion (n = 7), Dx perfusion abnormality was detected in planar and SPECT images in 3 (43%) and 4 patients (57%), respectively. In Dx branch disease with RCA lesion (n = 7), Dx perfusion abnormality was detected in only 1 (14%) and 2 patients (29%), respectively. In conclusion, SPECT is a useful modality for detecting Dx branch disease, but it is sometimes hard to detect Dx branch disease with LCX and RCA lesions.

Medium-term results of percutaneous transluminal balloon aortic valvuloplasty with Inoue balloon catheter for congenital aortic stenosis

Although percutaneous transluminal balloon aortic valvuloplasty (PTAV) has been performed for congenital aortic stenosis in infants and children for several years, its efficacy and the associated aortic regurgitation (AR) have not been widely discussed. Percutaneous transluminal balloon aortic valvuloplasty using an Inoue balloon catheter was performed for congenital aortic stenosis in 12 patients (4-16 years old) in this study. The systolic aortic valve pressure gradient ranged from 42 to 111 mmHg before PTAV and became < 50 mmHg immediately after PTAV in 10 cases (83%). Eight of these 10 patients had no increase in the gradient during subsequent observation for a period of 9-40 months. Aortic regurgitation increased immediately after PTAV in nine cases (75%). It increased from grade 1 to grade 2 in eight cases and from grade 1 to grade 3 in one patient; no significant enlargement of the left ventricular end-diastolic diameter and no significant change in the left ventricular end-diastolic pressure (LVEDP) or the cardiac index was observed during follow-up in these patients. There was a correlation between the diameter of the balloon and efficacy; an appropriate diameter was considered to be about 90% of the aortic annular diameter. Changes in the hemodynamic parameter after PTAV with an Inoue balloon were small in most patients and this procedure is considered to be a treatment that should be attempted prior to surgery for congenital aortic stenosis.

Detection of postural cerebral hypoperfusion with technetium-99m-HMPAO brain SPECT in patients with cerebrovascular disease

Seventeen of 19 patients (67 +/- 8 yr, 17 males and 2 females) had more than 75% unilateral stenosis or occlusion of the internal carotid or middle cerebral artery and two patients had carotid endarterectomy that previously had 90% stenosis of the internal carotid artery. They were studied during upright 99mTc-HMPAO brain SPECT. HMPA was injected immediately after arising from a supine position. Patients were classified into Group A (n = 10) with occlusion of the internal carotid or the middle cerebral artery or Group B (n = 9) with more than 75% unilateral stenosis of the internal carotid or the middle cerebral artery and with carotid endarterectomy. Additional cerebral blood flow perfusion abnormalities between upright and supine 99mTc-HMPAO brain SPECT were detected in seven patients in Group A and in only one patient in Group B. Semiquantitative analysis showed that the asymmetric ratios between upright and supine positions changed significantly in Group A from 0.82 +/- 0.15 to 0.89 +/- 0.10 (p < 0.01), but not in Group B, from 0.89 +/- 0.11 to 0.92 +/- 0.12 (ns). Additional perfusion abnormalities were relevant to occlusion of the internal carotid or middle cerebral artery indicated postural cerebral hypoperfusion. We conclude that upright 99mTc-HMPAO brain SPECT visualizes postural cerebral hypoperfusion possibly related to silent cerebral ischemia.

Species specificity of pharmacological characteristics of CCK-B receptors

Novel CCK-B receptor antagonists, tetronothiodin and L-156,586, showed different affinities for CCK-B receptors in brain membranes from human, rat, guinea pig and mouse. [125I]CCK-8 bound to these membranes with a similar affinity. However, tetronothiodin was most potent in rat (IC50 = 3.6 nM), followed by guinea pig (96 nM), human (210 nM) and mouse (280 nM). L-156,586 bound with highest affinity to membranes from guinea pig (11 nM), and with lowest affinity to membranes from mouse (220 nM). These results suggest the existence of species specificity of CCK-B receptors, and that these two compounds are useful tools for discrimination between these receptors.