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Ji Kang Park

Publications and source records attributed to Ji Kang Park.

11 recordsLinked to original sources
PubMed2005

Blood manganese concentration is elevated in iron deficiency anemia patients, whereas globus pallidus signal intensity is minimally affected.

OBJECTIVES: To determine whether blood manganese (Mn) concentration is elevated in patients with iron deficiency anemia (IDA), and whether this affects signal intensities in the globus pallidus. METHODS: Twenty-seven patients with IDA and 10 control subjects were tested for blood Mn, and brain magnetic resonance images (MRI) were also examined. Seventeen of the 27 patients were followed-up after iron therapy. RESULTS: IDA patients had a mean blood Mn concentration of 2.05 +/- 0.44 microg/dl, which was higher than controls. The mean pallidal index (PI) of anemic patients was not different from that of controls. There was a correlation between log blood Mn and PI (rho = 0.384, P = 0.048; n = 27) in IDA patients. None of the patients showed increased signals in the globus pallidus in T1-weighted MRI. Blood Mn levels decreased and hemoglobin levels increased after iron therapy (P < 0.05). CONCLUSION: Although blood Mn is elevated in IDA patients, there is no increase in globus pallidus MRI signal intensity. These findings stand in contrast to those of our other studies showing patients with chronic liver disease or occupational Mn exposure have elevated signal intensities remarkably.

Adult↗
PubMed2005

Low-dose and standard-dose unenhanced helical computed tomography for the assessment of acute renal colic: prospective comparative study.

PURPOSE: To compare the efficacy of low-dose and standard-dose computed tomography (CT) for the diagnosis of ureteral stones. MATERIAL AND METHODS: Unenhanced helical CT was performed with both a standard dose (260 mAs, pitch 1.5) and a low dose (50 mAs, pitch 1.5) in 121 patients suspected of having acute renal colic. The two studies were prospectively and independently interpreted for the presence and location of ureteral stones, abnormalities unrelated to stone disease, identification of secondary signs, i.e. hydronephrosis and perinephric stranding, and tissue rim sign. The standard-dose CT images were interpreted by one reviewer and the low-dose CT images independently by two reviewers unaware of the standard-dose CT findings. The findings of the standard and low-dose CT scans were compared with the exact McNemar test. Interobserver agreements were assessed with kappa analysis. The effective radiation doses resulting from two different protocols were calculated by means of commercially available software to which the Monte-Carlo phantom model was given. RESULTS: The sensitivity, specificity, and accuracy of standard-dose CT for detecting ureteral stones were 99%, 93%, and 98%, respectively, whereas for the two reviewers the sensitivity of low-dose CT was 93% and 95%, specificity 86%, and accuracy 92% and 94%. We found no significant differences between standard-dose and low-dose CT in the sensitivity and specificity for diagnosing ureter stones (P >0.05 for both). However, the sensitivity of low-dose CT for detection of 19 stones less than or equal to 2 mm in diameter was 79% and 68%, respectively, for the two reviewers. Low-dose CT was comparable to standard-dose CT in visualizing hydronephrosis and the tissue rim sign. Perinephric stranding was far less clear on low-dose CT. Low-dose CT had the same diagnostic performance as standard-dose CT in diagnosing alternative diseases. Interobserver agreement between the two low-dose CT reviewers in the diagnosis of ureter stones and alternative diseases, the identification of secondary signs, and tissue rim sign were high, with kappa values ranging from 0.769 to 0.968. On standard-dose CT scans, the calculated mean effective radiation dose was 7.30 mSv for males and 10.00 mSv for females. On low-dose CT scans, the calculated mean effective radiation dose was 1.40 mSv for males and 1.97 mSv for females. CONCLUSION: Compared with standard scans using 260 mAs, low-dose unenhanced helical CT using a reduced tube current of 50 mAs results in a concomitant decrease in the radiation dose of 81%. Although low-dose CT was limited in its ability to depict small-sized calculi less than or equal to 2 mm, it is still comparable to standard-dose CT for the diagnosis of ureter stones and alternative disease.

Acute Disease↗
PubMed2005

Whole blood and red blood cell manganese reflected signal intensities of T1-weighted magnetic resonance images better than plasma manganese in liver cirrhotics.

We examined whole blood (MnB), red blood cell (MnRBC), plasma (MnP) and urinary Mn (MnU) concentrations in 22 liver cirrhotics and 10 healthy controls to evaluate Mn concentration in which a fraction of biological samples best reflects pallidal signal intensities (pallidal index; PI) on T1-weighted magnetic resonance images (MRI) in liver cirrhotics. Increased signal intensity in the globus pallidus was observed in 18 (81.8%) of the 22 patients with liver cirrhosis. In a transplanted patient, increased pallidal signals also resolved as his liver function tests normalized after liver transplantation. There were significant correlations between MnB/MnRBC and PI (rho=0.529, rho=0.573, respectively) in liver cirrhotics, although no significant correlation was observed between MnP/MnU and PI. According to a multiple linear regression, MnB and MnRBC reflected the signal intensities of T1-weighted MRI better than MnP or MnU.

Adult↗
PubMed2005

Operator-dependent techniques for graded compression sonography to detect the appendix and diagnose acute appendicitis.

OBJECTIVE: The objective of our prospective study was to evaluate the value of various operator-dependent techniques that allow graded compression sonography to detect normal or abnormal vermiform appendix. SUBJECTS AND METHODS: A total of 877 subjects were included in this study. This sample population consisted of two groups: 202 control subjects and 675 patients who were suspected of having acute appendicitis. If detection of the appendix failed after a sufficient number of trials using graded compression scanning, appropriate operator-dependent techniques were used to help graded compression scanning to increase the detectability of the appendix further. The detection rate for the appendix in both groups and the diagnostic accuracy for acute appendicitis were obtained. RESULTS: The initial graded compression sonography examination depicted the appendix in 170 (84%) of 202 subjects in the control group and 601 (89%) of the 675 patients in the patient group. We then added operator-dependent techniques to graded compression sonography for the remaining patients in whom the appendix could not be detected. The additional use of the posterior manual compression technique, low-frequency convex transducer, upward graded compression technique, or left oblique lateral decubitus change of body position allowed graded compression sonography to depict the appendix in an additional 10, eight, six, and four patients in the control group, respectively, and in an additional 27, 23, 11, and seven patients in the patient group. The number of identified appendixes was increased to 198 (98%) of the 202 patients in the control group and to 669 (99%) of the 675 patients in the patient group. Graded compression sonography with operator-dependent techniques in the patient group yielded a sensitivity of 99% (319/321 patients), specificity of 99% (350/354), and an accuracy of 99% (669/675) for acute appendicitis. CONCLUSION: The addition of various operator-dependent techniques to graded compression sonography is useful for allowing improved visualization of both normal and abnormal appendixes.

Acute Disease↗
PubMed2003

Calcification mimicking manganese-induced increased signal intensities in T1-weighted MR images in a patient taking herbal medicine: case report.

Characteristic high signal intensities confined to the globus pallidus on T1-weighted magnetic resonance image (MRI) can be observed in manganese (Mn)-exposed workers, however, these high signals should be differentiated from those due to other causes such as fat, hemoglobin breakdown products, melanoma, neurofibromatosis, and calcification. A 39-year-old woman was admitted with mutism and involuntary movements which had developed the day before. She had ingested two packs of liquid herbal medicine containing 0.53 mg of Mn daily for 4 months prior to visiting our hospital. Her MRI showed high signals, confined mainly to the globus pallidus on T1-weighted images. Follow-up brain MRI at an interval of 11 months showed no interval change. Brain computed tomography (CT) at the time of the second MRI showed symmetric calcification on both globus pallidus. Blood levels of liver function tests, calcium, phosphorus, and parathyroid hormone were within normal ranges. The increased signals, which were first presumed to be induced by Mn, were concluded to be due to calcification based on the following reasons. First, follow-up brain MRI at an interval of 11 months did not show any interval change. Second, the ingested amount of 1.06 mg Mn daily for 4 months is even less than that added to mineral supplements for adults. Third, Mn-induced high signals in T1-weighted MRI do not show any abnormal findings in brain CT. The present case report suggests that brain CT should be performed to rule out symmetric calcification on basal ganglia in patients showing increased signals in T1-weighted MRI, but who do not have a significant exposure history to Mn. The present report also showed that the amount of 1.06 mg Mn daily ingested for 4 months did not cause the high signal in brain MRI.

Adult↗
PubMed2003

Whole blood manganese correlates with high signal intensities on T1-weighted MRI in patients with liver cirrhosis.

We examined whole blood (MnB), plasma (MnP) and urinary Mn (MnU) concentrations in 33 cirrhotics and 11 healthy controls to clarify: (1) whether, in chronic liver diseases, MnB or MnP reflects pallidal signal intensities in magnetic resonance imaging (MRI); and (2) which factors in chronic liver diseases correlate with pallidal signal intensities in T1-weighted MRI. Increased signal intensity in the pallidum was observed in 27 (81.8%) of 33 patients with liver cirrhosis in T1-weighted MRI. There was a significant correlation between MnB and pallidal index (PI) (gamma = 0.559, P < 0.01) in the patients. However, no significant correlation was observed between MnP and PI (gamma = 0.353, P > 0.05). According to a multiple linear regression, MnB reflected the signal intensities of T1-weighted MRI better than MnP or MnU. Child/Pugh score and total bilirubin level also correlated with PI. However, the hemoglobin level did not correlate with PI significantly.

Adult↗
PubMed2003

"Ovarian vascular pedicle" sign revealing organ of origin of a pelvic mass lesion on helical CT.

OBJECTIVE: We evaluated the "ovarian vascular pedicle" sign as a way of differentiating ovarian from subserosal uterine lesions on single-detector helical CT. SUBJECTS AND METHODS: We prospectively evaluated 131 patients who had a pelvic mass suspected of originating in the ovary or subserosal zone of the uterus and had undergone helical CT before surgery. A total of 108 ovarian lesions and 23 subserosal uterine myomas were confirmed. CT images were analyzed prospectively by consensus of two radiologists who thoroughly evaluated the retrograde tracing of the gonadal veins to the ovary or pelvic mass. To assess the value of analyzing the ovarian vascular pedicle sign in identifying the organ of origin of a pelvic mass, we compared statistical proportions for the frequencies of the sign in ovarian tumors and subserosal uterine myomas by performing the chi-square test. The probabilities for the presence of the ovarian vascular pedicle sign as a positive finding for a pelvic mass of ovarian origin were calculated. RESULTS: The presence of the ovarian vascular pedicle sign was identified in 92% (99/108) of ovarian masses and in 13% (3/23) of subserosal uterine myomas. The sign was statistically significant (p < 0.01) for differentiating a mass of ovarian origin from a mass of subserosal uterine origin. When the ovarian vascular pedicle sign on helical CT confirmed the ovarian origin, the sensitivity, specificity, positive predictive value and negative predictive value, and diagnostic accuracy were 92% (99/108), 87% (20/23), 97% (99/102), 69% (20/29), and 91% (119/131), respectively. CONCLUSION: The presence of the ovarian vascular pedicle sign on helical CT is valuable for confirming the ovarian origin of a pelvic tumor and for differentiating an ovarian tumor from subserosal uterine myoma.

Adult↗
PubMed2003

Cervicofacial actinomycosis: CT and MR imaging findings in seven patients.

BACKGROUND AND PURPOSE: Cervicofacial actinomycosis is uncommon, but without proper treatment it causes extensive tissue destruction. Early diagnosis is critical but usually difficult with cultures or imaging. Our aim was to identify characteristic imaging features that facilitated diagnosis in seven patients with cervicofacial actinomycosis. METHODS: We retrospectively reviewed the CT and MR findings in seven patients with pathologically proved actinomycosis. Histologic diagnosis was made by means of surgical excision or biopsy in seven patients. Culturing was performed in two patients. Enhanced CT scans (n=7) and MR images (n=2) were evaluated for the location, margin, infiltrative nature, enhancement pattern, and presence of lymphadenopathy. RESULTS: CT and MR images showed either a well-defined (n=2) or ill-defined (n=5) mass. Involved areas included the nasal cavity (n=2), buccal space (n=1), pyriform sinus (n=1), aryepiglottic fold (n=1), oro- and hypopharynx (n=1) and tongue (n=1). Imaging confirmed the infiltrative nature, showing the tendency of the lesion to invade across tissue planes and boundaries (n=6). Moderate homogeneous contrast enhancement was seen on CT scans in six patients with several small low-attenuating foci (n=2). T1- and T2-weighted MR images showed intermediate signal intensity with moderate contrast enhancement (n=2). Reactive lymphadenopathy was associated in three patients. CONCLUSION: Although cervicofacial actinomycosis occurs infrequently, it should be included in the differential diagnosis when images show a soft-tissue mass with inflammatory changes and an infiltrative nature in the cervicofacial area.

Actinomycosis, Cervicofacial↗
PubMedDate not supplied

CSF flow quantification of the cerebral aqueduct in normal volunteers using phase contrast cine MR imaging.

OBJECTIVE: To evaluate whether the results of cerebrospinal fluid (CSF) flow quantification differ according to the anatomical location of the cerebral aqueduct that is used and the background baseline region that is selected. MATERIALS AND METHODS: The CSF hydrodynamics of eleven healthy volunteers (mean age = 29.6 years) were investigated on a 1.5 T MRI system. Velocity maps were acquired perpendicular to the cerebral aqueduct at three different anatomical levels: the inlet, ampulla and pars posterior. The pulse sequence was a prospectively triggered cardiac-gated flow compensated gradient-echo technique. Region-of-interest (ROI) analysis was performed for the CSF hydrodynamics, including the peak systolic velocity and mean flow on the phase images. The selection of the background baseline regions was done based on measurements made in two different areas, namely the anterior midbrain and temporal lobe, for 10 subjects. RESULTS: The mean peak systolic velocities showed a tendency to increase from the superior to the inferior aqueduct, irrespective of the background baseline region, with the range being from 3.30 cm/sec to 4.08 cm/sec. However, these differences were not statistically significant. In the case of the mean flow, the highest mean value was observed at the mid-portion of the ampulla (0.03 cm(3)/sec) in conjunction with the baseline ROI at the anterior midbrain. However, no other differences were observed among the mean flows according to the location of the cerebral aqueduct or the baseline ROI. CONCLUSION: We obtained a set of reference data of the CSF peak velocity and mean flow through the cerebral aqueduct in young healthy volunteers. Although the peak systolic velocity and mean flow of the CSF differed somewhat according to the level of the cerebral aqueduct at which the measurement was made, this difference was not statistically significant.

Adult↗