Biomedical subjects

M C Han

Publications and source records attributed to M C Han.

At least 235 records · Page 13Linked to original sources

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↗

PubMedDate not supplied

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↗

PubMedDate not supplied

Malignant schwannomas of the thorax: CT findings.

We reviewed CT of eight patients with malignant schwannomas arising in the thorax. Only one patient had neurofibromatosis. Five lesions occurred in the posterior mediastinum, one lesion was in the middle mediastinum, and two lesions were in the chest wall. Common CT findings were the presence of low-density areas (six of eight), compression of adjacent structures (six of eight), pleural abnormalities (six of eight), such as pleural effusion or pleural nodules, and metastatic pulmonary nodules (five of eight). Pleural abnormalities or pulmonary nodules were detected in seven of eight patients. These CT findings can help in differentiating malignant schwannoma from benign neurogenic tumor.

Adult↗

PubMedDate not supplied

Tuberculosis of the ribs: CT appearance.

Tuberculosis is the most common inflammatory lesion of the ribs, second only to metastatic neoplasm as a destructive cause of a rib lesion. We retrospectively analyzed CT findings of 13 lesions in eight patients with pathologically proven rib tuberculosis. The presenting symptoms were painful mass in five, chest pain in two, and nontender mass in one. Five patients had concomitant pulmonary tuberculosis. On CT, all showed a juxtacostal soft tissue mass with central low attenuation and peripheral rim enhancement (a so called "cold abscess"). Only 4 of 13 lesions demonstrated bone destruction: two were osteolytic expansile lesions with cortical disruption and two were mild cortical irregularities. Five lesions were located at the costochondral junction, five were in the rib shaft, two were in the sternochondral junction, and one was in the costovertebral joint. There was no evidence of direct extension into the lung parenchyma.

Adolescent↗

PubMedDate not supplied

Non-Hodgkin lymphoma of the central skull base: MR manifestations.

OBJECTIVE: The aim of this study was to demonstrate the MR characteristics of non-Hodgkin lymphoma of the skull base to help in the differential diagnosis of this neoplasm from other conditions. MATERIALS AND METHODS: MR of five patients, 7-64 years old, with pathologically proved lymphomas of the skull base were reviewed. Three cases had primary skull base lesions involving the sphenoid bone and the cavernous sinus. One case with a nasal cavity lesion involving the skull base and one with a relapsing skull base lesion of previously treated tonsillar lymphoma were included. RESULTS: The lesions had signal intensities that were similar to that of gray matter of brain on both T1- and T2-weighted imaging. Bilateral cavernous sinuses were involved with encasement of internal carotid arteries in every case. Postcontrast MR showed homogeneous enhancement of the tumor with dural infiltration along the planum sphenoidale, clivus, or tentorium. The clivus was destroyed or replaced by tumors in adult cases but in two children the clivus was preserved with intact sphenooccipital synchondrosis. In one case the tumor extended to the extracranial portion through the jugular foramen. CONCLUSION: The MR findings of a permeative lesion of the skull base, invasion of the cavernous sinus without arterial narrowing, infiltration along the dural surface, and an iso- or hypointensity with brain on T2-weighted imaging should suggest lymphoma.

Cavernous Sinus↗

PubMedDate not supplied

Milk of calcium pleural collections: CT findings.

OBJECTIVE: Chest radiography and CT findings of five patients with milk of calcium pleural collections are described. MATERIALS AND METHODS: The diagnosis was based on needle aspiration in four patients and the presence of a fat-calcium level on CT in the remaining one. Four patients had a prior history of pleurisy. RESULTS: Characteristic radiographic findings were homogeneous increased opacity with a double contour at the interface with the lung. Computed tomography showed that the lateral contour was the margin of the milk of calcium and the medial contour was the margin of the thickened visceral pleural facing the lung. On CT milk of calcium collection appeared as a homogeneous area of increased attenuation. CONCLUSION: Recognition of the characteristic double contour on plain radiography would help prevent or avoid an erroneous diagnosis of pleural or extrapleural solid mass.

Calcium Carbonate↗

PubMedDate not supplied

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↗

PubMedDate not supplied

Hepatic choriocarcinoma in a neonate: MR appearance.

We present the MR findings of hepatic choriocarcinoma in a 2-week-old infant. Two masses of heterogeneous signal intensity were evident; one was an extensive mass on the left side of the liver and the other was a "daughter" nodule in the right lobe. Peripheral portions of the masses were hyperintense on T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI) suggesting subacute hemorrhage. Central portions of the masses were hypointense on T1WI and bright on T2WI. T1-weighted postgadolinium imaging showed peripheral enhancement of both tumor nodules. The infant's mother had normal serum beta-human chorionic gonadotropin levels and pelvic CT.

Biomarkers, Tumor↗

PubMedDate not supplied

Adenoma malignum of uterine cervix in Peutz-Jeghers syndrome: CT and US features.

We report CT and ultrasound (US) features of adenoma malignum of the uterine cervix in a patient with Peutz-Jeghers syndrome (PJS) in whom bilateral ovarian mucinous cystadenomas and sex cord tumors with annular tubules were associated. Adenoma malignum was shown as a hyperechoic mass mixed with multiple cysts on US and a low attenuated endocervical mass on CT. We think that imaging demonstration of an endocervical mass is important for the correct diagnosis of adenoma malignum in a female with PJS.

Adenocarcinoma↗

PubMedDate not supplied

Sclerosing hemangiomas of the lung and interlobar fissures: CT findings.

OBJECTIVE: Sclerosing hemangioma is a rare pulmonary tumor. This article describes CT features of the tumor on the basis of CT-pathology correlation. MATERIALS AND METHODS: The CT features of eight patients with sclerosing hemangioma of the lung were studied retrospectively and were correlated with the pathologic findings of the resected specimens. All eight patients had an incidental lung mass found on chest radiographs. Seven patients were female. Contrast enhancement of the masses was assessed visually by two radiologists independently, and the density was measured before and after contrast enhancement by using a standard cursor in three patients. RESULTS: On CT, sclerosing hemangiomas appeared as well defined juxtapleural masses in all cases. The tumors enhanced by visual criteria in all but one patient with the smallest mass. The CT density of the enhancing mass ranged from 96 to 157 HU. Three patients had calcification and two had well defined areas of low attenuation. On CT-pathology correlation, the higher, iso-, and lower attenuation areas corresponded with angiomatous, solid and sclerotic, and cystic areas, respectively. CONCLUSION: A well defined juxtapleural mass with marked contrast enhancement coupled in select cases with foci of sharply marginated areas of low attenuation and calcification are characteristic CT findings of sclerosing hemangioma and should suggest this diagnosis especially in women with these findings.

Adult↗

PubMedDate not supplied

Mediastinal Castleman disease: CT findings.

OBJECTIVE: Our objective was to characterize the CT findings of mediastinal Castleman disease. MATERIALS AND METHODS: We reviewed the CT findings of mediastinal Castleman disease in 10 patients. RESULTS: In nine cases of hyaline-vascular type Castleman disease, lymph nodes were 2-7 cm in diameter and located in the hilum in six patients, superior mediastinum in two patients, and posterior mediastinum in one patient. On CT the tumors were well-demarcated round masses showing dense homogeneous enhancement after contrast medium injection. Dynamic CT in one case showed gradual centripetal enhancement of the mass. In one case of hyaline-vascular type Castleman disease, lumpy and irregular calcifications were noted in the center of the mass. In the one case of plasma cell type Castleman disease, multiple small homogeneously enhancing nodes were found in the mediastinal and supraclavicular area. CONCLUSION: CT findings may suggest the preoperative diagnosis of mediastinal Castleman disease.

Adolescent↗

PubMedDate not supplied

Entry tears of thoracic aortic dissections: MR appearance on gated SE imaging.

OBJECTIVE: The purpose of this study was to assess the ability of gated SE MR to demonstrate entry tears of thoracic aortic dissections and to elucidate their MR appearance. MATERIALS AND METHODS: Gated SE MR images of nine consecutive patients with nonthrombosed aortic dissection on aortography were retrospectively analyzed. RESULTS: Magnetic resonance consistently depicted an intimal flap and a double lumen in all nine patients. A focal intimal flap discontinuity suggesting an intimal tear was shown in eight patients. This intimal flap discontinuity was confirmed to be the entry tear by operation in five patients and by aortography in three. In five of eight patients with a focal intimal flap discontinuity, rapid influx of blood across an intimal defect produced a localized signal void area within the false lumen, which was surrounded by slow flow signal showing even-echo rephasing. This MR sign of a localized jet of flow void within the false lumen was very useful in determining the significance of a focal intimal flap discontinuity. CONCLUSION: Familiarity with these MR appearances of entry tears may enable their preoperative localization in a large proportion of aortic dissections on routine gated SE MRI.

Adult↗

PubMedDate not supplied

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↗

PubMedDate not supplied

Pulmonary nocardiosis: CT findings.

OBJECTIVE: To evaluate CT findings of pulmonary nocardiosis in immunocompromised patients. MATERIALS ALND METHODS: Five patients with bacteriologically confirmed pulmonary nocardiosis were evaluated. Four patients were receiving corticosteroids with or without other immunosuppressive drugs for lupus nephritis (two patients), idiopathic thrombocytopenic purpura (one patient), and renal transplantation (one patient), and one patient had long-standing diabetes. Nocardia asteroides was isolated from blood culture, bronchial washing, pleuropulmonary aspirates, or open lung biopsy. Plain chest radiography and CT were performed on all patients, and follow-up CT was performed on one patient. RESULTS: On CT there were pleural effusion (four patients), air-space consolidation with internal low attenuation with or without cavities (four patients), multiple noncavitating pulmonary nodules and subpleural pulmonary nodules (three patients), and chest wall extension (three patients). Follow-up CT after treatment showed marked improvement of the pleural and pulmonary lesions. CONCLUSION: In the immunocompromised and chronically debilitated host, pulmonary nocardiosis should be included in differential diagnosis if chest CT shows consolidation with low attenuation areas with or without cavitation, multiple pulmonary nodules, pleural effusion, and chest wall extension.

Adrenal Cortex Hormones↗

PubMedDate not supplied

Complications of Klebsiella pneumonia: CT evaluation.

OBJECTIVE: To evaluate the CT features of complicated Klebsiella pneumonia. MATERIALS AND METHODS: We retrospectively reviewed 15 CT examinations from 11 consecutive patients with complicated Klebsiella pneumonia with special attention to internal architecture of pneumonic consolidation and its changes on follow-up CT. On plain radiography, abscess or cavitation was suspected in all patients. The diagnosis was established by isolation of Klebsiella pneumoniae from blood in six patients, from sputum in two, and from both in three. Five patients underwent follow-up CT due to progression (one) or incomplete resolution (four) of the disease despite antimicrobial therapy. RESULTS: In all patients pneumonic consolidation was composed of two intermingled components: enhancing homogeneous areas and poorly marginated low-density areas with multiple small air cavities, suggesting necrotizing pneumonia. In nine patients scattered enhancing structures probably due to atelectatic lung and pulmonary vessels were noted within necrotic areas of consolidated lung. In eight patients pleural complications such as effusion (all) or diffuse pleural enhancement (five) were seen. In two patients with multilobar disease and delayed treatment, multiple small abscess cavities coalesced to form a large cavity with sloughing of lung tissue, suggesting pulmonary gangrene and lung abscess formation on 18 and 45 day follow-up CT, respectively. In three other patients necrotizing pneumonia resolved slowly from the periphery to the center with residual fibrosis on follow-up CT at 2-3 months. CONCLUSION: The most common CT manifestation of complicated Klebsiella pneumonia was necrotizing pneumonia associated with pleural abnormalities. In extensive cases, pulmonary gangrene or lung abscess was a rare complication.

Adult↗

PubMedDate not supplied

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↗

PubMedDate not supplied

Lobular low attenuation of the lung parenchyma on CT: evaluation of forty-eight patients.

PURPOSE: Our goal was to analyze patients with pulmonary lobular low attenuation (LLA) on thin section CT with regard to the underlying pulmonary diseases and the dynamic changes occurring in the low attenuation regions during respiration. METHOD: Forty-eight consecutive patients with LLA on thin section CT were analyzed retrospectively. Forty-six patients (95%) had symptoms related to respiratory disease, such as productive cough (n = 25) and hemoptysis (n = 18). Only two patients, one with chronic pulmonary embolism and one with Takayasu arteritis combined with bronchiectasis, had pulmonary vascular disease. Six patients, four with bronchiectasis and two with vascular disease, were studied with dynamic CT during forced vital capacity maneuver. Attenuation values for LLA areas and adjacent lung were measured and time-density curves were plotted. RESULTS: Forty-one (85%) patients had bronchiectasis, typically in other than the regions of the LLA. Areas with proximal bronchiectasis showed low attenuation but without notable lobular distribution. Pulmonary vessels in the LLA areas were smaller than those of adjacent normal lung (n = 45). Of 22 patients who underwent pulmonary function tests, 15 had obstructive pattern of impairment. Respiratory dynamic CT showed expiratory air trapping in LLA areas in all six patients. The mean attenuation values of LLA areas were lower than those of the adjacent normal lung by 67 HU at end-inspiration and by 165 HU at end-expiration (p = 0.002). CONCLUSION: The majority of the patients with LLA shown by thin section CT had bronchiectasis elsewhere in the lung, and evidence of air trapping in the LLA was clearly demonstrated. Bronchiolar obstruction may be the most prevalent cause for the development of LLA.

Adult↗