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Biomedical subjects

K J Jung

Publications and source records attributed to K J Jung.

At least 19 recordsLinked to original sources
PubMed2001

Mediastinal interfaces and lines in children: radiographic-CT correlation.

BACKGROUND: Various mediastinal interfaces and lines are well known in adults, but not fully understood in children. OBJECTIVE: To review the mediastinal interfaces and lines on plain radiographs in the paediatric age group with CT correlation. MATERIALS AND METHODS: Soft copies of 195 sets of CT examinations and concurrent chest radiographs in 180 paediatric patients (age 1 month to 15 years) were retrospectively reviewed. The frequency of visualisation and the anatomical basis of the mediastinal interfaces and lines were assessed. The evaluated mediastinal interfaces and lines were superior vena cava interface, descending aorta interface, left paraspinal interface, azygoesophageal recess interface, right paratracheal stripe, anterior junction line and posterior junction line. RESULTS: Chest radiographs showed the SVC interface in 161, the descending aorta interface in 155, the left paraspinal interface in 98, the azygoesophageal recess in 94, the right paratracheal stripe in 53, the anterior junction line in 15 and the posterior junction line in 10. Non-visualisation of mediastinal interfaces and lines on plain radiographs was explained by normal anatomical difference compared with the adult and underlying intrathoracic abnormalities when they were correlated with CT. The frequency of visualisation of the SVC interface, descending aortic interface, left paraspinal interface and azygoesophageal recess fluctuated with age, while the frequency of the right paratracheal stripe, anterior junction line and posterior junction line increased with age. CONCLUSIONS: Awareness of the frequency of visualisation and the anatomical basis of the mediastinal interfaces and lines in paediatric patients may be helpful for interpretation of chest radiographs.

Adolescent↗
PubMed2001

Large cell neuroendocrine carcinoma of the lung: clinical, CT, and pathologic findings in 11 patients.

The purpose of this study was to describe the clinical, computed tomographic (CT), and pathologic findings of large cell neuroendocrine carcinoma (LCNEC) of the lung. CT and pathologic findings as well as clinical features of surgically proven LCNEC of the lung were reviewed retrospectively in 11 consecutive patients (eight men and three women; mean age, 63 years; range, 44-77 years). Chest CT showed peripheral mass or nodule (n = 8) and central mass with distal atelectasis (n = 3). Six tumors were accompanied by mediastinal (n = 3) and hilar (n = 3) lymph node enlargement at CT. On pathologic examination, all resected tumors showed necrosis of variable extent (mean: 38%, range; 10-70%). The areas of intrinsic lipoid pneumonia and tumor emboli in two patients appeared at CT as areas of ground-glass opacity surrounding the tumor. Mediastinal nodal metastases were seen in three (27%) patients. Pathologic staging of 11 patients was IB in six, IIA in one, IIB in one, IIIA in two, and IIIB in one. Follow-up data showed extrathoracic metastases in four patients at mean follow-up period of 15 months. One patient died of distant metastasis 5 months after the surgery. CT findings of LCNEC of the lung are nonspecific and similar to those of other non-small cell lung cancers and extrathoracic metastasis is seen in approximately one third of the patients with follow-up study.

Adult↗
PubMed2001

Malignant thymic epithelial tumors: CT-pathologic correlation.

OBJECTIVE: The purpose of our study was to describe and compare the CT and pathologic findings of atypical thymoma and thymic carcinoma. MATERIALS AND METHODS: Twenty-seven consecutive patients (14 men, 13 women ranging in age from 22 to 77 years [mean age, 52 years]) with pathologically proven atypical thymoma (n = 9) and thymic carcinoma (n = 18) constituted the study population. The chest CT findings in each of the 27 patients were reviewed retrospectively in consensus by two chest radiologists. These findings were correlated with pathologic findings. RESULTS: The tumors were located in the anterior mediastinum, and most tumors had a lobulated margin (24/27, 89%). Atypical thymomas were significantly smaller (mean, 4.7 cm) than thymic carcinomas (mean, 7.2 cm) (p = 0.041) on CT. The findings of invasion of the great vessels, lymph node enlargement, extrathymic metastases, and phrenic nerve palsy were seen only in patients with thymic carcinoma. The frequencies of necrosis, intratumoral calcification, pleural effusion, pleural implants, pericardial effusion, and obliteration of the mediastinal fat plane were not significantly different between atypical thymomas and thymic carcinomas (p > 0.05). Various histologic subtypes were included in thymic carcinoma. The tumor necrosis and calcification seen on CT were confirmed at pathologic examination. CONCLUSION: When a large thymic tumor appears with invasion of the great vessels, lymph node enlargement, phrenic nerve palsy, or extrathymic metastases on CT, thymic carcinoma rather than atypical thymoma should be considered.

Adult↗
PubMed2001

Predictors for benign solitary pulmonary nodule in tuberculosis-endemic area.

BACKGROUND: Solitary pulmonary nodule (SPN) may show different presentation in tuberculosis (TB)-endemic countries. The aim of this study was to identify clinical and radiological predictors favoring benign or malignant SPN in TB-endemic region. METHODS: Two hundred one SPNs in 201 consecutive Korean patients were included (< 3 cm in diameter, all confirmed by pathology or bacteriology, 93 benign and 108 malignant diseases). For clinical parameters, age, sex, smoking status and amount, and past history of pulmonary tuberculosis and diabetes mellitus were investigated retrospectively. For radiological parameters, size, location, margin characteristics, presence of calcification, pleural tag, surrounding satellite nodule, cavitation, internal low attenuation, open bronchus sign, surrounding ground-glass opacity, enhancement pattern of the SPNs and mediastinal lymph node (LN) enlargement were analyzed on chest CT scans. RESULTS: Patients with a older age (60.7 +/- 9.6 vs 56.2 +/- 13.1, p = 0.008) and more than 40-pack years smoking (27.8% vs 14.0%, p = 0.017) were more frequently related with malignant than benign SPN. On chest CT scans, spiculated margin, contrast enhancement more than 20 Hounsfield unit and presence of pleural tag and mediastinal LN enlargement were more frequently observed in malignant than benign SPNs. In contrast to previous studies, satellite lesions (21.5% vs 1.9%, p < 0.001) and cavitation (20.4% vs 5.6%, p = 0.001) were more frequently seen in benign than malignant SPN. Positive predictive values of benignity were 90.9% and 76.0%, respectively, when satellite lesions and cavitation were found in cases of SPN. CONCLUSION: Satellite lesions and cavitation on chest CT scan could be useful predictors for benign SPN in TB-endemic areas.

Adult↗
PubMed2000

Development and characterization of a flavoring agent from oyster cooker effluent.

The general composition of concentrated oyster cooker effluent (OCE) was 80% moisture, 6.7% total nitrogen, 2.4% glycogen, and 8.5% ash. Optimum conditions for enzymatic hydrolysis of OCE were 50 degrees C, 2 h of reaction time, 0.1% amylase mixture (alpha-amylase plus glucoamylase), and 0.2% protease NP. Hydrolysis of OCE led to an increase in free amino acids, with taurine comprising approximately 20% of the total. Inosine monophosphate was predominant (456 mg/100 g) among nucleotides and related compounds. Enzyme hydrolysis increased extractable nitrogen by approximately 2-fold. Trimethylamine, trimethylamine oxide, and total creatinine levels were not affected by enzyme treatment. Predominant aroma-active components of enzyme-hydrolyzed OCE included 2-acetyl-1-pyrroline and 3-(methylthio)propanal. Results of this study may help alleviate the wastewater disposal problem currently caused by OCE.

Animals↗
PubMed2000

Low-dose, volumetric helical CT: image quality, radiation dose, and usefulness for evaluation of bronchiectasis.

RATIONALE AND OBJECTIVES: The aim of our study was to assess the image quality, radiation dose, and clinical applicability of low-dose, volumetric helical CT in the evaluation of bronchiectasis. METHODS: Volumetric helical CT scans (120 kVp, 3-mm collimation, pitch of 2, and reconstruction interval of 2 mm) were obtained through the thorax at four levels of tube current: 150, 100, 70, and 40 mA. There were a total of 12 patients who underwent CT scan either for suspected bronchiectasis or for lung cancer screening, with three patients allocated to each current level. Five radiologists assessed and compared image quality of the helical CT scans obtained at the various exposure levels. Radiation doses of helical CT performed with four different current settings and of high-resolution CT (120 kVp, 170 mA, 1-mm collimation, and 10-mm intervals) were measured. The diagnostic usefulness of the 40-mA helical CT images was compared with that of high-resolution CT by two observers in 52 patients with known or suspected airway diseases. RESULTS: With helical CT, there was no significant difference in image quality among the four different levels of current (P > 0.05). Radiation doses associated with the 40-, 70-, 100-, and 150-mA helical techniques were 3.21 mGy (range, 3.02-3.57), 4.81 mGy (range, 3.89-5.93), 6.46 mGy (range, 6.01-7.31), and 10.4 mGy (range, 8.93-12.1), respectively, whereas that of high-resolution CT was 2.17 mGy (range, 1.90-2.67). Of 52 patients, 44.5 and 47 patients (the mean of positive interpretations by the five observers) were diagnosed with bronchiectasis at high-resolution and low-dose helical CT, respectively. Of 928 segments, bronchiectasis was seen in 152.5 segments on high-resolution CT and in 193.5 segments on helical CT. The interobserver agreement (k-values) was acceptable for both techniques. CONCLUSIONS: With acceptable images and similar radiation dose, low-dose volumetric helical CT at 40 mA may offer more information than does high-resolution CT in the evaluation of bronchiectasis.

Adult↗
PubMed1996

New double-quantum filtering schemes.

New double-quantum filtering (DQF) schemes are theoretically developed by reformulating the equations describing the double-quantum (DQ) signal. The equations describing the second- and third-rank DQ signals are simplified by restricting the RF phases as required for DQF. The equations are then factorized into two terms representing the separate contribution to the DQ signal from the RF pulses involved in the preparation and evolution times. This allows analysis of the DQ signal of a particular DQF scheme separately for each of these times in a concise manner. By use of the reformulated equations, the conventional DQF scheme is shown to be only one of four possible DQF schemes. The three new DQF schemes offer some desirable properties over the conventional DQF scheme. In the conventional DQF scheme, the third-rank DQ signal declines rapidly to null as the flip angles of the creation and readout RF pulses deviate from 90 degrees to 54.7 degrees or 125.3 degrees. In addition, the second- and third-rank DQ signals in the conventional DQF scheme are opposite in their polarities, resulting in attenuation of the total DQ signal due to destructive interference between them. In one of three new DQF schemes, the DQ signal does not vanish at 54.7 degrees and 125.3 degrees, but varies smoothly with the same functional dependence on the RF flip angles as the second-rank DQ and triple-quantum signals. Furthermore, in two of the three new DQF schemes, the second- and third-rank DQ signals have the same polarity so that the total DQ signal may be enhanced through constructive interference between them. These features of new DQF schemes have been confirmed experimentally.

Gels↗
PubMed1996

Superconducting receiver coils for sodium magnetic resonance imaging.

We present the results from sodium magnetic resonance imaging (MRI) experiments using high-temperature superconducting (HTS) receiver coils. Sodium imaging has been shown to have great potential for the assessment of cell integrity but suffers from a substantially lower signal-to-noise ratio (SNR) than that of a hydrogen imaging. The use of an HTS receiver coil was found to significantly increase the SNR relative to an equivalent copper receiver coil at room temperature. The SNR gains afforded by HTS coils can also be used to decrease the imaging time.

Copper↗
PubMed1995

Breakthrough of single-quantum coherence and its elimination in double-quantum filtering.

Breakthrough of single-quantum coherence is shown to occur after application of a double-quantum filter with the conventional four-step phase-cycling scheme. This single-quantum breakthrough is due to the intersequence stimulated echo which has been generated by the radiofrequency pulses in the preceding pulse sequence and appears at the same time as the double-quantum coherence signal in the current pulse sequence. Moreover, the phase of the intersequence stimulated echo is the same as the phase of the double-quantum coherence signal; i.e., the phase of the intersequence stimulated echo is twice the phase change of the radiofrequency pulses in the creation period when their phase is rotated in accordance with the conventional four-step phase-cycling scheme. Consequently, the intersequence stimulated echo passes through the double-quantum filtration in the conventional four-step phase-cycling scheme and gradient pulses. A new phase-cycling scheme which can filter out the single-quantum breakthrough signal is proposed here and its effectiveness is verified experimentally and by computer simulations.

Computer Simulation↗
PubMed1993

Self-correction of proton spectroscopic images for gradient eddy current distortions and static field inhomogeneities.

A postprocessing method of correcting for gradient eddy current distortions and inter-voxel static field inhomogeneity in spectroscopic imaging is presented. Data is acquired normally and all spatial processing is performed. The FID in each voxel is then digitally filtered to extract the signal from a single reference line. Phase multiplying the original FID by the phase of this reference signal corrects for gradient eddy currents and static field offsets. Computer simulations show that the method is robust with respect to noise, filter bandwidth and the presence of small lines close to the reference line. The method is demonstrated on proton spectroscopic images of phantoms.

Computer Simulation↗
PubMed1991

Reduction of flow artifacts in NMR diffusion imaging using view-angle tilted line-integral projection reconstruction.

Most of the diffusion imaging techniques employ strong diffusion gradient pulses of long duration in order to achieve appreciable signal attenuation through the diffusion effect. However, these strong and long gradient pulses make the resultant images extremely sensitive to the motion or flow of the object. Fourier imaging, with which most of the current NMR imaging is performed, is especially sensitive to the fluctuating flow and the images are usually obscured by severe flow artifacts smeared in the phase-encoding direction. In this paper, we have proposed a diffusion imaging technique which reduces the flow artifacts by use of the line-integral projection reconstruction (LPR) imaging method. Furthermore, the inhomogeneity artifacts expected to occur in LPR imaging have been corrected by application of the view-angle tilting technique. The pulse sequence of the view-angle tilted LPR diffusion imaging is designed in such a way that it works for both isotropic and anisotropic diffusion. Experimental results are presented along with the experimental procedures.

Brain↗
PubMed1990

MR Fourier transform arteriography using spectral decomposition.

Reliable separation of arteries from other stationary tissues is accomplished through spectral decomposition by exploiting the pulsatile nature of the blood flow in the arteries. Fourier transformation of a series of projection images in the temporal direction along the cardiac cycle results in spectral images where the arteries are a part of the harmonic component images while stationary tissues and veins are represented as a de component image. From the magnitude of the spectral images an arteriogram can be obtained by summation of the harmonic component images excluding the de component image. This principle is applied to Fourier imaging in a cine mode data acquisition as well as line scan imaging. Since there is no need for the encoding of the flow-sensitive gradient, this technique is free from eddy current artifacts which have been one of the major obstacles to projection angiography using the flow-encoding gradient.

Arteries↗
PubMedDate not supplied

Halo sign on high resolution CT: findings in spectrum of pulmonary diseases with pathologic correlation.

The halo sign in a pulmonary nodule refers to the condition in which soft tissue attenuation of a pulmonary nodule is surrounded by peripheral ground glass attenuation on high resolution CT. The halo sign can be caused by several pathologic processes: hemorrhagic pulmonary nodules, tumor cell infiltration, and nonhemorrhagic inflammatory lesions. Hemorrhagic pulmonary nodules may occur in infectious diseases including invasive pulmonary aspergillosis, mucormycosis, and candidiasis and noninfectious diseases including Wegener granulomatosis and primary and metastatic hemorrhagic tumors. Tumor cell infiltration in bronchioloalveolar carcinoma, pulmonary lymphoma, and pulmonary metastatic neoplasm may appear with the halo sign. Eosinophilic lung disease and organizing pneumonia are representative of inflammatory lesions showing the sign.

Hemorrhage↗
PubMedDate not supplied

Primary tumors and mediastinal lymph nodes after neoadjuvant concurrent chemoradiotherapy of lung cancer: serial CT findings with pathologic correlation.

PURPOSE: The purpose of this work was to describe the changes of primary tumor and mediastinal lymph nodes on CT after neoadjuvant concurrent chemoradiotherapy and to correlate the CT findings with pathology. METHOD: Twenty-one consecutive patients [N2 disease (n = 19) or resectable T4 and N2 disease (n = 2)] with non-small cell lung cancer underwent neoadjuvant concurrent chemoradiotherapy. Changes of primary tumor and mediastinal nodes before and after the therapy were assessed using CT. The CT findings were correlated with pathologic findings. RESULTS: With neoadjuvant therapy, decrease in T stage was achieved in 9 of 21 (43%) patients on CT. On pathology, the remaining tumor consisted mostly of fibrosis and necrosis with little proportion of viable tumor cells (mean volume 17%, range 0-55%). Decrease in nodal stage was achieved in 14 of 21 (67%) patients on pathologic examination. Seven patients had cancer cells in mediastinal lymph nodes: in 6 of 9 (67%) patients with adenocarcinoma and 1 of 12 (8%) patients with squamous cell carcinoma (p = 0.016). CONCLUSION: With neoadjuvant concurrent chemoradiotherapy, the remaining tumor consists mostly of fibrosis or necrosis. Decreased nodal stage on pathology is achieved especially in patients with N2 disease of squamous cell carcinoma. The CT findings of the tumor and mediastinal nodes are not helpful in predicting the pathology after the therapy.

Adenocarcinoma↗
PubMedDate not supplied

Pulmonary tuberculosis: CT and pathologic correlation.

Typical CT findings of active postprimary pulmonary tuberculosis include centrilobular nodules and branching linear structures (tree-in-bud appearance), lobular consolidation, cavitation, and bronchial wall thickening. The CT findings of inactive pulmonary tuberculosis include calcified nodules or consolidation, irregular linear opacity, parenchymal bands, and pericicatricial emphysema. The typical appearance of primary tuberculosis on CT scans is homogeneous, dense, well-defined segmental or lobar consolidation with enlargement of lymph nodes in the hilum or the mediastinum. Miliary nodules may be seen in primary and postprimary tuberculosis. On CT, tuberculomas appear as a nodule with surrounding satellite nodules and internal cavitation on CT. Atypical radiologic manifestations of tuberculosis, encountered in as many as one third of the cases of adult-onset tuberculosis, are single or multiple nodules or masses, basilar infiltrates, miliary tuberculosis with diffuse bilateral areas of ground-glass opacity, and reversible multiple cysts. Underlying histopathologic findings of typical and atypical CT findings of tuberculosis are caseating granulomas or pneumonia in the active phase and fibrosis and dystrophic calcification in the inactive phase.

Adult↗
PubMedDate not supplied

T1 lung cancer on CT: frequency of extrathoracic metastases.

PURPOSE: To determine the frequency of extrathoracic metastases in T1 non-small-cell lung cancer. METHOD: Ninety patients with T1 lung cancer identified on CT were included. Extrathoracic metastases were evaluated at the time of initial diagnosis and during a 1-year follow-up study. The frequency of metastases was compared in terms of cell type (squamous or nonsquamous), size (<2 cm or >2 cm), and the initial CT findings of the tumor. RESULTS: Extrathoracic metastases were identified in 12 (13%) of 90 patients at the time of diagnosis and in 10 patients at the 1-year follow-up study (total, 22 of 90 [24%] patients). Tumors with ground-glass opacity on CT were associated with a significantly lower prevalence of metastases (p = 0.042). The area of ground-glass opacity was seen in 1 of 13 (85%) patients with bronchioloalveolar carcinoma and in 12 of 53 (23%) patients with adenocarcinoma other than bronchioloalveolar carcinoma (p < 0.001). There was no significant difference in the prevalence of metastases between squamous and nonsquamous cell carcinoma, between tumors smaller than 2 cm (n = 17) and larger than 2 cm in diameter (n = 73) and between tumors with or without mediastinal nodal metastases (p>0.05). CONCLUSION: Extrathoracic metastases were apparent at the initial examination in 13% of patients and at the 1-year follow-up examination in 11% of patients. The prevalence is significantly lower in tumors with ground-glass opacity.

Carcinoma, Non-Small-Cell Lung↗