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Biomedical subjects

J K Han

Publications and source records attributed to J K Han.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

MR imaging of advanced gastric cancer: comparison of various MR pulse sequences using water and gadopentetate dimeglumine as oral contrast agents.

BACKGROUND: To evaluate clinical usefulness of oral contrast agents (gadopentetate dimeglumine and water) and to assess proper magnetic resonance (MR) imaging in evaluating advanced gastric cancer (AGC) by comparing different MR imaging techniques. METHODS: Fifteen patients with AGC were imaged with a 1.0-T MR imager and body-array coil. All patients underwent surgery or laparascopic biopsy. Fast low-angle shot (FLASH), half-Fourier single-shot turbo spin-echo (HASTE), and true fast imaging with steady-state precession time (FISP) images were obtained after ingestion of 900 mL tap water in each patient, followed by postcontrast FLASH images after additional ingestion of gadopentetate dimeglumine (Gd-DTPA). Qualitative analysis including T-staging of AGC and scoring of imaging quality and quantitative analysis were performed prospectively. RESULTS: In image quality and diagnostic accuracy of T-staging, FLASH imaging showed results slightly superior to those of other imaging modalities, and there was no great difference between using water and Gd-DTPA as an oral contrast agent. As for cancer-to-gastric lumen contrast-to-noise ratio (CNR), HASTE and true FISP imaging were superior to FLASH imaging with Gd-DTPA (p < 0.0001). In cancer-to-pancreas CNR, FLASH imaging without Gd-DTPA showed the best result. CONCLUSIONS: The use of Gd-DTPA as a positive contrast agent may not be imperative, and T1-weighted FLASH imaging in combination with true FISP imaging with ingestion of tap water can be very useful in evaluating AGC with MR imaging.

Administration, Oral↗
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Heterotopic pancreas of the stomach: CT findings correlated with pathologic findings in six patients.

BACKGROUND: The purpose of this study was to characterize the computed tomographic (CT) findings of heterotopic pancreas of the stomach. METHODS: CT scans of six surgically proven cases of heterotopic pancreas of the stomach were reviewed. Three were dynamic spiral CT scans, with both arterial dominant and late phase scans. In other three, both unenhanced and contrast-enhanced scans were obtained by using conventional techniques. Particular attention was given to the enhancement of the heterotopic pancreas. Pathologic and surgical findings were correlated with CT findings. RESULTS: The locations were in the gastric antrum in five cases and in the mid-body in one. Size ranged from 1 cm to 3 cm (mean = 2.1 cm). Three cases showed homogeneous, strong enhancement similar to the pancreas and consisted mainly of pancreatic acini with the same histologic features as the normal pancreas. Two cases showed poor enhancement and consisted mainly of ducts and hypertrophied muscle; pancreatic acini were a minor component. In one case appearing as a cystic lesion on CT, a pseudocyst was found with many ducts and some nests of pancreatic acini. CONCLUSIONS: Heterotopic pancreas of the stomach showed a diverse spectrum of CT findings. Good understanding of these CT findings may be helpful in making a correct diagnosis.

Adolescent↗
PubMedDate not supplied

Gastric adenoma with atypical appearance: findings on double-contrast barium study with histopathologic correlation.

BACKGROUND: To describe the radiologic findings of nonpolypoid gastric adenomas and to correlate them with pathologic findings. METHODS: During a 9-year period, we reviewed 49 pure gastric adenomas in 43 patients with positive radiologic findings. Of these adenomas, seven with atypical polypoid appearance were retrospectively included in the study. We reviewed these findings with double-contrast barium study and correlated them with the pathologic findings. RESULTS: Of seven nonpolypoid adenomas, four were depressed and three were flat at pathologic examination. All were diagnosed as early gastric carcinoma (five as type IIc, one as type IIb, one as type IIa + IIc) in upper gastrointestinal series. Three were located in the gastric angle, two in the lower body, and two in the antrum. Size ranged from 10 mm to approximately 25 mm (mean = 15 mm). Six lesions had nodular surface and five had convergency of the mucosal folds. A shallow depressed area was seen in six lesions. CONCLUSIONS: A considerable proportion of gastric adenomas presents as a depressed or flat lesion on double-contrast barium study because of histologic characteristics of decreased subjacent mucosa. Because the nonpolypoid adenoma has a greater potentional for malignancy, more precaution is needed during the follow-up of this uncommon lesion.

Adenoma↗
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Vascular complications in lumbar spinal surgery: percutaneous endovascular treatment.

Four patients underwent endovascular treatment of vascular injuries complicating lumbar spinal surgery. In two patients with massive retroperitoneal hemorrhage, the extravasating lumbar arteries were successfully embolized with microcoils. Two patients with large iliac arteriovenous fistula (AVF) were treated, one with embolization using a detachable balloon and coils, which failed, and the other with placement of a stent graft after embolization of distal runoff vessels, which occluded the fistula. We conclude that acute arterial laceration or delayed AVF complicating lumbar spinal surgery can be managed effectively with selective embolization or stent-graft placement, respectively.

Adult↗
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Prediction of optimal injection protocol for tumor detection in contrast-enhanced dynamic hepatic CT using simulation of lesion-to-liver contrast difference.

The detection of hepatic lesions in computed tomography (CT) is improved when a contrasting material is administered intravenously, but it depends considerably on how this agent is injected. In this study, we constructed a compartment model for a liver containing a hepato-cellular carcinoma (HCC), and simulated the difference in lesion-to-liver contrast enhancement. Using this model, we simulated the effects of various injection factors on the detectability of a lesion and searched for the optimal injection protocol for detecting tumors in contrast-enhanced dynamic hepatic CTs. We found that the mass injection rate, or k-value (in mg/s), (which is the volume injection rate, in ml/s, multiplied by the contrast agent concentration, in mg/ml) plays a critical role in the injection protocol optimized for tumor detection, and has a unique value for a given body weight independent of the total injection dose.

Adult↗
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Superselective transcatheter arterial embolization with ethanol and iodized oil for hepatocellular carcinoma.

PURPOSE: The effectiveness of superselective transcatheter arterial embolization with a mixture of ethanol and iodized oil was evaluated for hepatocellular carcinoma. PATIENTS AND METHODS: The procedure was attempted in 14 male patients with hepatocellular carcinoma. The tumor was a single small (2-5 cm in diameter) hypervascular nodule in all patients, except in one patient with two nodules. Superselective catheterization was performed with use of coaxial technique into the third-order branch of the feeding hepatic artery. Under fluoroscopy, 1-4 mL of 75% ethanol mixed with iodized oil was infused. RESULTS: Complete segmental or subsegmental devascularization of the feeding arteries and tumor vascularities occurred in all patients. Follow-up CT or angiography after 9-37 months revealed decrease of tumor in six of nine nonsurgical cases. Subsequent segmentectomy or tumorectomy in five patients revealed total or near-total necrosis of the tumor and thickening of capsules, explaining the halo seen around the tumor on CT scans and the relatively intact surrounding parenchyma seen microscopically. CONCLUSION: Superselective transcatheter arterial embolization with ethanol and iodized oil is a safe method for treatment of small nodular hepatocellular carcinoma with a prominent feeding artery.

Adult↗
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Interventional management of benign obstruction of the hepatic inferior vena cava.

PURPOSE: The effectiveness of interventional treatment of benign obstruction of the hepatic segment of the inferior vena cava (IVC) was evaluated in a retrospective analysis. PATIENTS AND METHODS: Among 21 patients, 14 obstructions were membranous (type 1) and seven were segmental (type 2). IVC thrombosis was found proximal to the obstruction in five patients. Percutaneous transluminal angioplasty (PTA) was attempted in patients with type 1 obstruction with use of a double balloon technique in most cases (12 of 14 cases). For six of the seven patients with type 2 obstruction, metallic stent placement and PTA were performed with or without urokinase thrombolysis or percutaneous aspiration thrombectomy. Follow-up evaluation was performed with vena cavography, pressure measurement, and liver function tests. RESULTS: The overall initial success rate was 95% (20 of 21 cases). The mean pressure gradient across the obstruction decreased significantly from 14.1 mm Hg +/- 4.1 to 4.2 mm Hg +/- 3.7 (P < .01) in 10 patients with type 1 obstruction and from 15.7 mm Hg +/- 3.1 to 6.0 mm Hg +/- 3.3 (P < .05) in six patients with type 2 obstructions. During the follow-up period from 6 months to 6 years, patency was maintained in nine of 10 patients with type 1 obstruction. Among the seven patients with type 2 obstruction, restenosis developed in two. Intimal thickening inside the metallic stent was found on the follow-up vena cavogram for all six patients who underwent stent placement. CONCLUSION: For the interventional treatment of benign obstruction of the hepatic IVC, PTA with the double balloon technique is effective for the membranous type (type 1), and combined interventions including PTA, thrombolysis with urokinase, percutaneous aspiration thrombectomy, and metallic stent placements seem effective in the treatment of the segmental type (type 2). The long-term effects, including intimal thickening in cases involving the use of metallic stents, warrant further investigation.

Adult↗
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Renal angiomyolipoma: embolotherapy with a mixture of alcohol and iodized oil.

PURPOSE: To evaluate the efficacy of superselective embolotherapy of renal angiomyolipomas with a 1:3 mixture of iodized oil and absolute ethanol as embolic material. MATERIALS AND METHODS: Fifteen patients with 21 symptomatic renal angiomyolipomas were treated with embolization. The sizes of tumors ranged from 6 cm to 15 cm (mean, 8.6 cm). Six of 15 patients were diagnosed with tuberous sclerosis. The diagnoses of renal angiomyolipoma were made from characteristic computed tomographic findings. All angiomyolipomas were successfully embolized with a 1:3 mixture of iodized oil and absolute ethanol (2-20 mL; mean, 8.5 mL). Patients were followed up from 5 months to 8 years (mean, 35.6 months). The efficacy of embolotherapy was evaluated by symptom-free period, immediate and late complications, and follow-up imaging findings, including changes in tumor size. RESULTS: Thirteen patients showed no symptom recurrence during follow-up periods from 3 months to 8 years. Two patients with incomplete embolization required repeated embolization because of the recurrence of perinephric hematoma or other symptoms. Twelve patients experienced mild postembolization syndrome, which subsided with conservative management. A moderate amount of pleural effusion developed in one patient and was managed with percutaneous drainage. No patients developed any severe late complications, hypertension, or renal failure. During the follow-up period, 12 tumors decreased in size, whereas there was no change in eight tumors, and in one tumor imaging follow-up was not available. CONCLUSION: Embolization with a 1:3 mixture of iodized oil and absolute ethanol is an effective method of treatment in renal angiomyolipoma with favorable results. But incomplete embolization of angiomyolipoma results in a high incidence of recurrent symptoms due to bleeding.

Adolescent↗
PubMedDate not supplied

Transcatheter oily chemoembolization of the inferior phrenic artery in hepatocellular carcinoma: the safety and potential therapeutic role.

PURPOSE: To evaluate the efficacy and safety of transcatheter oily chemoembolization therapy (TOCE) via the inferior phrenic artery (IPA) in hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Fifty patients with HCC underwent a total of 82 procedures of TOCE of the IPA, as well as of the hepatic artery. In 16 patients, additional extrahepatic collaterals were depicted and were also embolized in 10 patients. TOCE was performed with an emulsion of iodized oil and doxorubicin hydrochloride, and gelatin sponge particle embolization was added in 32 patients. RESULTS: Initial response showed complete or partial remission of the tumor in 31 patients. The cumulative survival rates after combined TOCE of the hepatic artery, IPA, and other extrahepatic arteries were 89% (6 months), 78% (1 year), 46% (2 year), and 30% (3 year), when calculated from the time of IPA chemoembolization. Liver abscess and empyema developed in one case of combined IPA and multiple intercostal artery chemoembolization. There were no serious complications after IPA chemoembolization alone. CONCLUSION: TOCE of the IPA has a potential therapeutic role as a safe adjunct to TOCE of the hepatic artery in the management of HCC supplied by the IPA.

Adult↗
PubMedDate not supplied

Direct invasion of urinary bladder from sigmoid colon cancer: CT findings.

Radiological findings in three cases of sigmoid colon carcinoma invading the urinary bladder are reported. An irregular spiculated margin or nodular indentations in region of bladder dome were seen on intravenous urography. A soft tissue mass contiguous with an irregularly thickened urinary bladder wall and a circumferentially thickened sigmoid colon wall were demonstrated on CT and sonography and led to the correct diagnosis.

Adenocarcinoma↗
PubMedDate not supplied

Infarction of the kidney: role of contrast enhanced MRI.

Magnetic resonance imaging was performed on nine kidneys in six patients with renal infarction caused by renal arterial embolism secondary to cardiac valvular disease. The time interval between the onset of the symptoms attributable to renal infarction and the date of MRI was 2-23 days. On both T1- and T2-weighted images the signal intensity of the infarcted area was lower than that of the noninfarcted area in six kidneys and higher in three kidneys. Postcontrast T1-weighted images demonstrated the extent of the infarction except in the kidney in which the infarcted areas had high signal intensity on precontrast T1-weighted images.

Adult↗
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Hypointense boundary layer between slow flow and mural thrombus on spin-echo MR.

To evaluate the ability of spin-echo MRI to differentiate between slow flow and mural thrombus in aortic diseases, we reviewed the spin-echo MRI of 10 patients with intraaortic thrombus that had been documented by CT in 8 patients and aortography in 2 patients. Six patients had aortic aneurysms with mural thrombi, and four had aortic dissections with adherent mural thrombi within the false lumen. Five of seven gated oblique sagittal or coronal T1-weighted studies demonstrated hyperintense slow flow signal within the residual lumen. This hyperintense slow flow signal was accompanied by a parallel hypointense rim due to a boundary layer dephasing phenomenon. Eight axial T2-weighted MR studies demonstrated a hypointense zone due to fresh clot at the edge of a mural thrombus on even-echo images consistently. The hypointense boundary layer between slow flow and mural thrombus on either gated T1-weighted MRI or second-echo T2-weighted MRI not only predicted the presence of flow within the residual lumen but also clearly separated the area of slow flow from that of mural thrombus in 9 of 10 patients. Proper interpretation of spin-echo images may obviate the need for phase display imaging or gradient-echo imaging in differentiating between slow flow and mural thrombus.

Adult↗
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Preoperative staging of uterine cervical carcinoma: comparison of CT and MRI in 99 patients.

OBJECTIVE: The aim of this study was to compare CT and MRI at 0.5 T in the preoperative staging of uterine cervical cancer in a large series of patients. MATERIALS AND METHODS: Ninety-nine patients with uterine cervical carcinoma underwent CT, MRI, and surgical exploration. RESULTS: Both CT and MR findings were compared using surgical-pathologic findings as gold standards. Magnetic resonance imaging was superior to CT in tumor detection (sensitivity 75 vs. 51%, p < 0.005), in parametrial evaluation (accuracy 87 vs. 80%, p < 0.005), in overall tumor staging (accuracy 77 vs. 69%, p < 0.025), and in pelvic lymph node evaluation (accuracy 88 vs. 83%, p < 0.01). Magnetic resonance imaging had an accuracy of 76% in assessment of the thickness of cervical stromal invasion. CONCLUSION: Magnetic resonance imaging was superior to CT in preoperative staging of uterine cervical carcinoma and MRI should be used instead of CT for preoperative staging of this disease.

Carcinoma↗
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MR findings of secondary hemochromatosis: transfusional vs erythropoietic.

OBJECTIVE: The aim of this study was to demonstrate the MR characteristics of secondary hemochromatosis (transfusional versus erythropoietic). MATERIALS AND METHODS: Magnetic resonance images of five patients with transfusional (n = 3) or erythropoietic (n = 2) hemochromatosis were reviewed. RESULTS: The liver of all patients had low signal intensity in all pulse sequences. The spleen had low signal intensity in all patients with transfusional iron overload, but normal signal intensity in erythropoietic hemochromatosis, which had similar MR findings to idiopathic hemochromatosis. However, the pancreas had variable signal intensity. CONCLUSION: On MRI the signal intensity of the spleen may allow distinction between transfusional and erythropoietic hemochromatosis.

Adult↗
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Intraperitoneal drop metastases from hepatocellular carcinoma: CT and angiographic findings.

UNLABELLED: Our goal was to describe the radiological manifestations of intraperitoneal drop metastases (IPDMs) from hepatocellular carcinoma (HCC). METHODS: Seven patients with clinically (n = 4) or pathologically (n = 3) proven IPDMs from HCC were retrospectively analyzed. Medical records, CT scans (n = 7), and angiographic findings (n = 5) were reviewed. RESULTS: On CT scans, all seven patients had single or multiple nodular masses in the liver. In six patients, the hepatic masses showed an exophytic growth. Single (n = 4) or multiple (n = 3) discrete omental masses, 3-10 cm in diameter, were also demonstrated in all patients. Intratumoral necrosis in the omental mass and engorgement of adjacent omental vessels were demonstrated in five and three patients, respectively. On angiography, the omental masses showed hypervascularity supplied by omental branches (n = 4) and superior mesenteric (n = 2) and inferior mesenteric (n = 1) artery and also showed prominent draining veins. CONCLUSION: The radiological manifestations of IPDM from HCC are single or multiple discrete hypervascular masses in the omentum. These are quite different from those of usually carcinomatosis peritonei.

Adult↗