Isao Umehara

Beat-to-beat evaluation of cardiac function during recovery from upright bicycle exercise in patients with coronary artery disease

The purpose of this study was to evaluate the time course of cardiac function during recovery from upright bicycle exercise in patients with coronary artery disease. Twelve patients with coronary artery disease performed a symptom-limited exercise test on a cycle ergometer. Left ventricular function was continuously monitored during exercise and recovery with a computerized cadmium telluride detector following the intravenous injection of technetium-labeled red blood cells. Although the end-diastolic volume (153.4 +/- 76.1 ml) and end-systolic volume (100.5 +/- 67.3 ml) at the end of exercise were significantly higher than the respective resting values, stroke volume (52.8 +/- 16.1 ml) and ejection fraction (38.0 +/- 12.2%) were not different from the respective resting values. The recovery of cardiac output was relatively slow compared with that of heart rate, because stroke volume rose sharply early in recovery. The rise in stroke volume was chiefly a result of a significant decrease in end-systolic volume between 1 and 4 minutes of recovery. These changes may result from an immediate afterload reduction coupled with a relatively slow decrease in sympathetic stimulation. The time course of cardiac function during recovery from exercise in cardiac patients is substantially different from that of normal subjects and may be a sensitive way to evaluate the peripheral vascular function and deteriorated cardiac function in cardiac patients.

Asymptomatic arteriovenous malformation of the pancreas. Demonstration by Doppler ultrasonography and magnetic resonance imaging.

SummaryWe reported a case of asymptomatic pancreatic AVM, incidentally found on routine ultrasonography and diagnosed noninvasively by means of Doppler ultrasonography and MRI. The diagnosis was confirmed by angiography. This is the first report to demonstrate the characteristics of pancreatic AVM by these two imaging techniques. They proved to be useful in identifying the vascular nature of AVM without the use of a contrast material, which is a definite advantage over DSA and CT. The quality of the image obtained was equivalent or superior to that obtained by DSA and contrast-enhanced CT. Doppler ultrasonography and MRI may serve as the primary imaging techniques of choice in suspected cases of AVM.

Diagnosis of aneurysmal bone cyst of the mandible. A report of two cases with emphasis on scintigraphic approaches.

Aneurysmal bone cyst is rarely found in the mandible, and roentgenographic diagnosis of this condition is not easily made. In this report, the diagnostic value of bone scintigraphy and radionuclide angiography and CT imaging in two cases of aneurysmal bone cyst of the mandible are discussed. Bone scintigraphy with Tc-99m MDP demonstrated ring-like or doughnut-pattern accumulation of radioactivity, which corresponded to the expansile character of the bony lesion. The accumulation of radioactivity was intensive in the peripheral region despite the fact that the lesion was benign. Furthermore, the central rarefaction showed that the lesion was cystic. Radionuclide angiography with Tc-99m HSA, including blood pool scan, did not detect radioactive concentration. Thus bone scintigraphy and radionuclide angiography were found to be essential in the differential diagnosis of aneurysmal bone cyst from other forms of tumor, especially hypervascularized tumor and central hemangioma of the mandible.

Comprehensive analysis of perfusion scintigraphy in Takayasu's arteritis.

One hundred eighty perfusion lung scans of 120 patients with Takayasus arteritis were retrospectively evaluated. Lung scans were abnormal in 76% of the patients. Lung scans could be classified into four groups, according to the pattern of perfusion defects. Early involvement occurred in the upper lobes, and the middle and lower lobes were involved at a later stage. The data obtained by physiological examination (spirography and arterial blood gas analysis) showed a weak relationship with the severity of perfusion lung scan findings. In addition, repeated lung scans were found to be easy and reliable in the follow-up period of pulmonary artery involvement.

F-18 FDG PET/CT of polymyalgia rheumatica.

Abstract:We performed F-18 FDG PET/CT on a 69-year-old woman with polymyalgia rheumatica. In this case, FDG accumulated not only in the major joints of the extremities but also in the lumbar region. The anatomic structure on the PET/CT fused images turned out to be intervertebral joints, interspinal

Is 18F-FDG PET/CT useful for distinguishing between primary thyroid lymphoma and chronic thyroiditis?

Purpose This study aims to investigate the usefulness of 18F-FDG PET/CT for distinguishing between primary thyroid lymphoma (PTL) and chronic thyroiditis. Methods We retrospectively reviewed the data of 196 patients with diffuse 18F-FDG uptake of the thyroid gland and enrolled patients who were diagnosed as having PTL or chronic thyroiditis based on the medical records, pathological findings, and laboratory data. The enrolled patients comprised 10 PTL patients (M/F = 4:6) and 51 chronic thyroiditis patients (M/F = 8:43). Images had been acquired on a PET/CT scanner at 100 minutes after intravenous injection of 18F-FDG. Results The PTL group consisted of 7 patients with diffuse large B-cell lymphoma (DLBCL) and 3 with mucosa-associated lymphoid tissue (MALT) lymphoma. The maximum standardized uptake value (SUVmax) was significantly higher in the PTL group than that in the chronic thyroiditis group (25.3 ± 8.0 and 7.4 ± 3.2, P < 0.001). On the other hand, the CT density (Hounsfield unit: HU) was significantly lower in the PTL group than that in the chronic thyroiditis group (46.1 ± 7.0 HU and 62.1 ± 6.9 HU, P < 0.001). Within the PTL group, the SUVmax was significantly higher in the cases of DLBCL than in those of MALT lymphoma (29.0 ± 6.4 and 16.7 ± 2.3, P = 0.017). Conclusions The SUVmax was significantly higher and the CT density was significantly lower in PTL as compared with those in chronic thyroiditis. Thus, 18F-FDG PET/CT may be useful for distinguishing between PTL and chronic thyroiditis.

The Use of Three-phase Scintigraphy for Diagnosing Hemangiomas of the Extremities: A Clinical Evaluation

Five hemangiomas were found in four patients and were assessed by three-phase blood perfusion and blood-pool scintigraphy to determine the usefulness of this method for the imaging characteristics of different types of hemangiomas of the extremities. After injecting Tc-99m RBC or Tc-99m DTPA HSA, dynamic perfusion and early and delayed pool images were obtained and analyzed. The perfusion images of one cavernous hemangioma and two venous hemangiomas showed normal activity, but blood-pool imaging showed increased activity, whereas on perfusion imaging and early blood-pool imaging, another cavernous hemangioma showed a partial increase in activity in its periphery and on delayed blood-pool imaging, diffuse increase in activity. Further, the remaining hemangioma, a mixed-type hemangioma, showed, diffuse increase in activity on both perfusion and blood-pool imaging. Thus, three-phase scintigraphy was found useful in evaluating and achieving a diagnosis of a hemangioma of the extremities.

Tl-201 myocardial SPECT in patients with systemic arterial diseases.

We compared the results of Tl-201 myocardial SPECT of patients with arteriosclerosis obliterans (ASO), abdominal aortic aneurysm (AAA), and Takayasu arteritis (TA), so that coronary artery disease could be evaluated in them. Twenty-three patients (ASO, 9; AAA, 8; TA, 6) had Tl-201 myocardial SPECT with stress testing, and SPECT data was assessed qualitatively and quantitatively. Qualitative analysis showed that myocardial perfusion was decreased most in patients with ASO, followed by patients with AAA, and was minimally decreased in patients with TA. Quantitative analysis indicated that segmental uptake was significantly less in four segments in ASO compared with TA, less in two segments in AAA compared with TA, and less in two segments in ASO compared with AAA. Thus patients with ASO and AAA were found to have a marked abnormality in Tl-201 myocardial SPECT, indicating that this procedure should be performed in these patients. In patients with TA, however, because of minimal abnormality in myocardial perfusion, the role of SPECT is limited.

Bilateral renal angiomyolipoma in a patient with tuberous sclerosis treated with resection of one kidney and transarterial embolization of other kidney using CT during selective arteriography: a case report

Renal AML complicating tuberous sclerosis shows a rapid growth and its rupture is frequently associated with hemorrhagic shock as a result of profuse retroperitoneal bleeding, necessitating an aggressive therapeutic approach. This report describes the long-term clinical progress of 28 year-old woman with tuberous sclerosis with a ruptured giant AML that underwent unilateral nephrectomy, who has been followed up after treatment with concomitant application of computed tomography during selective arteriography to conserve the remaining normal renal parenchyma, and in whom the need for initiation of dialysis has been successfully avoided, with conspicuous reduction of the tumor size.

Scintigraphic Diagnosis of Rib Lesions in Patients with Lung Carcinoma

One hundred twenty-five patients with carcinoma of the lung received 171 pyrophosphate bone scans. Twentythree (18%) of these 125 patients had abnormal uptake only in the ribs. Of these 23 patients, 14 (61%) were diagnosed as having a benign lesion. Five showed direct invasion from the primary carcinoma and another four were diagnosed as having metastatic rib lesions. Benign rib lesions were also suspected in several patients with multiple metastases.