Biomedical subjects

Jianming Tian

Publications and source records attributed to Jianming Tian.

3 recordsLinked to original sources

PubMed2004

Star algorithm: detecting the ultrasonic endocardial boundary automatically.

In clinical practice, interuser variability, high computational cost and low image quality are always big problems that puzzle the clinical application of computer-aided echocardiographic boundary detection. Star algorithm (StaA) is a new endocardial boundary detector that has been designed to overcome these problems. The purpose of the paper is to present the detection details of the algorithm and evaluate its clinical value. The main elements of StaA are radial search technique, cost function-driven system and self-designed edge detector. The algorithm has four main steps: image preprocessing, initial left ventricular chamber detection, left ventricular chamber center detection and left ventricular endocardial boundary detection. StaA was performed on 50 pairs of end-diastolic (ED) and end-systolic (ES) echocardiographic images, which were divided into high image-quality group (HImQ) and low image-quality group (LImQ). The results of the test were analyzed in two ways: 1. Compared with the manually-traced boundary, the mean relative radial error (MRRerr) of the computer-detected boundary was 12.07% and there is no significant difference of MRRerr between HImQ and LImQ. 2. The two-dimensional (2-D) ejection fraction calculated by the computer detected boundary (EFa) can be used interchangeably with that calculated by the manually-traced boundary (EFm). The test proves that simple and effective methods can also make the echocardiographic boundary detector automatic, quick and robust.

Algorithms↗

PubMed2003

Computerized tomography guided percutaneous ethanol injection for the treatment of hyperfunctioning pheochromocytoma.

PURPOSE: We validated the therapeutic efficacy of computerized tomography (CT) guided percutaneous ethanol injection (PEI) for hyperfunctioning pheochromocytoma. MATERIALS AND METHODS: Pheochromocytoma was treated with CT guided PEI in 41 patients, including 19 men and 22 women with a mean age of 42 years (range 31 to 59). Of the 41 patients 40 had a solitary adrenal benign pheochromocytoma (18 on the left and 22 on the right side), which was diagnosed by biopsy in 36 and by typical clinical manifestations, laboratory and CT findings in 4. The remaining patient with malignant pheochromocytoma, who underwent surgical resection 2 years ago, had 2 recurrent lesions along the right sympathetic chain. RESULTS: CT or magnetic resonance imaging followup 7 to 20 days after treatment showed that adrenal benign pheochromocytoma disappeared in 27 patients and became completely necrotic or shrank in 13. The 2 malignant recurrent lesions also disappeared completely. During the followup of 23 to 54 months the foci disappeared completely in 31 patients, and shrank and completely necrotized in 10. All patients showed normal blood pressure without intermittent vertigo, complexion pallor or numbness of the 4 extremities. Blood and urine catecholamine was also within the normal range. CONCLUSIONS: The therapeutic efficacy of CT guided PEI for hyperfunctioning pheochromocytoma is definite and worth widespread application because the procedure is safe, microtraumatic and less costly, and has low morbidity.

Adrenal Gland Neoplasms↗

PubMed2003

CT-guided percutaneous ethanol injection of the thymus for treatment of myasthenia gravis.

OBJECTIVE: This study was designed to validate the therapeutic effectiveness of CT-guided percutaneous ethanol injection of the thymus for the treatment of myasthenia gravis. SUBJECTS AND METHODS: The subjects were 45 patients with myasthenia gravis. The diagnosis was determined by the patients' histories, physical findings, neostigmine tests, and morphologic changes. According to the Osserman classification, the 45 patients with myasthenia gravis were classified as stage I (n = 26), stage III (n = 13), and stage IV (n = 6). A 21- or 22-gauge needle was inserted into the thymus under CT guidance, and then ethanol was injected step by step until it was distributed throughout the whole thymoma, the hyperplasia of the thymus, or the normal thymus. The amount of ethanol injected ranged from 2 to 13 mL, with a mean of 7 mL. RESULTS: CT follow-up at 3-4 weeks showed that the thymus or thymoma was completely or mostly necrotized. CT follow-up at 3 months showed that the vertical, transverse, and anteroposterior dimensions of the thymus in all 45 myasthenia gravis patients decreased by 59.2%, 68.6%, and 73.2%, respectively, compared with those before percutaneous ethanol injection treatment. The therapeutic effect was observable clinically 2 days after treatment in 44 patients, including 36 patients who were able to open their eyes after treatment. A 5-year follow-up study showed that the condition markedly improved in 35 patients, improved in nine patients, and failed to improve in one patient who did not respond to the treatment. After treatment, 37 patients presented with low-grade fever (range, 37.3-37.7 degrees C; mean, 37.5 degrees C), which resolved 3 days later without treatment; all 45 patients complained of mild retrosternal pain after ethanol injection. CONCLUSION: The therapeutic effect of CT-guided percutaneous ethanol injection into the thymus of patients with myasthenia gravis is definite. This procedure is safe and has low morbidity. CT-guided percutaneous ethanol injection is a minimally invasive alternative treatment for myasthenia gravis.

Adolescent↗