Using Ultrasound Elastography for Making the Differential Diagnosis of Thyroid Nodules / 대한내분비외과학회지

PURPOSE: Ultrasound (US) elastography is a newly developed imaging technique for assessing tissue stiffness by measuring the degree of the tissue's deformation in response to the application of an external force. This technique has recently been applied for making the diagnosis of nodular thyroid disease. The purpose of this study was to evaluate the diagnostic utility of US elastography for differentiating benign thyroid nodules from malignant thyroid nodules. METHODS: A total of 63 consecutive patients with thyroid nodules and who were referred for surgical treatment were examined in this study. Seventy-five nodules in these patients were examined by US B-mode, color Doppler US and US elastography. The final diagnosis was obtained from the histologic findings. The tissue stiffness on ultrasound elastography was scored from 1 (elasticity in the whole nodule) to 5 (no elasticity in the nodule and in the posterior shadowing). RESULTS: On US elastography, 18 of 32 benign nodules (56.3%) had a score of 1 to 3, whereas 23 of 43 malignant nodules (62.8%) had a score of 4 to 5. With applying a US elastography score of 4-5 as an indicator for malignancy, the sensitivity, specificity, positive predictive value and negative predictive value of US elastography were 65.9%, 52.9%, 62.8% and 56.3%, respectively. Of the 14 follicular tumors, 12 were follicular adenoma and four were follicular carcinoma. The sensitivity and specificity of US elastography for diagnosing follicular carcinoma were 50.0% and 81% (56=69), respectively. The positive and negative predictive values were 55.2% (16=29) and 60.0%, respectively. The accuracy of the technique was 57.1%. The findings of US elastography were not significantly correlated with the histopathologic findings. CONCLUSION: This study has shown that US elastography may be not useful for differentiating between benign and malignant thyroid nodules. Further studies are needed to confirm the usefulness of US elastography for making the differential diagnosis of thyroid nodules.

Usefulness of MR Cholangiopancreatography after Intravenous Morphine Administration

PURPOSE: We wanted to assess the usefulness of MRCP after intravenous morphine administration in the evaluation of the hepatopancreatic pancreatico-biliary ductal system. MATERIALS AND METHODS: We studied 15 patients who were suspected of having disease of hepatopancreatic ductal system and they did not have any obstructive lesion on ultrasonography and/or CT. MRCP was acquired before and after morphine administration (0.04 mg/kg, intravenously). Three radiologists scored the quality of the images of the anatomic structures in the hepatopancreatic ductal system. We directly compared the quality of the images obtained with using the two methods and the improvement of the artifacts by pulsatile vascular compression. RESULTS: The MRCP images obtained after intravenous morphine administration were better than those obtained before morphine administration for visualizing the hepatopancreatic ductal system. On direct comparison, the MRCP images obtained after morphine administration were better in 12 cases, equivocal in two cases, and the images before morphine administration were better in only one case. In three patients, MRCP before morphine injection showed signal loss at the duct across the pulsatile hepatic artery. In two of three patients, MRCP after morphine injection showed no signal loss in this ductal area. CONCLUSION: MRCP after intravenous morphine administration enables physicians to see the hepatopancreatic ductal system significantly better and the artifacts caused by pulsation of the hepatic artery can be avoided.

Comparison of (18F)FDG PET/CT and CT/MRI for the Diagnosis of Recurrent or Metastatic Disease after Treatment: In Head and Neck Cancer Patients

PURPOSE: We evaluated the accuracy of 18FFDG PET/CT for the detection of recurrence or metastasis after treatment in patients with primary head and neck cancer, and compared the results with those of CT/MRI. MATERIALS AND METHODS: We studied 34 patients with the diagnosis of head and neck cancer, who underwent treatment and follow up with 18FFDG PET/CT and CT/MRI. The patients were divided into two subgroups based on the difference in follow-up time interval and the type of treatment. Accuracy was evaluated by follow-up information and histopathology findings. The results of the 18FFDG PET/CT and CT/MRI were compared by statistical analysis. RESULTS: For the 18FFDG PET/CT results, 19 FDG uptake lesions were detected in 17 patients. Among these lesions, 18 were confirmed as recurrent or metastatic lesions and one as an inflammatory reaction from radiation therapy. Four lesions that had high FDG uptake were not detected by the CT/MRI. The sensitivity and specificity were 100% and 94.4% for the 18FFDG PET/CT and 77.8% and 94.4% for the CT/MRI (p<0.05). For the subgroup that received radiation therapy, 18FFDG PET/CT was more sensitive than CT/MRI (sensitivity = 100% vs. 63.6%, p<0.05). CONCLUSION: The results of this study showed that 18FFDG PET/CT was a useful screening modality for detecting recurrent or metastatic disease after treatment of patients with head and neck cancer, especially post-radiation.

Malignant Nodular Hidradenoma: A Case Report

Malignant nodular hidradenoma is a rare skin appendageal tumor, and its imaging findings have not been previously described. We experienced the case of a large malignant nodular hidradenoma of the left upper arm in a 71-year-old woman. MRI revealed a large, lobular, poorly circumscribed, soft tissue mass at the left upper arm, and the mass showed homogeneous enhancement. 18F-FDG PET/CT showed hypermetabolic activity in the left upper arm mass with a maximal standard uptake value of 19.

A Case of Langerhans Cell Histiocytosis with Hypothalamic Mass / 대한소아혈액종양학회지

A 14-month-old girl presented with petechial skin lesions and polydipsia was diagnosed as Langerhans cell histiocytosis (LCH) and responded fairly well to multiple chemotherapies using vincristine, cyclophosphamide, and prednisone. 3 years later, relapses were more common with short periods of remissions in spite of using more intensive therapy with vinblatine and etoposide. At age of 4.5, sudden weight gain and abnormal behavior led to MRI study and revealed an hypothalamic mass. Radiation of 1, 800 cGy was given to the mass and followed by a 75% decrease in measuring and remission of the obesity. Although, there was no evidence of tumor progression in the hypothalamus, she died of sepsis due to systemic progression of the disease at age of 5. LCH commonly present with the symptoms of diabetes insipidus, but hypothalamic mass is not common. We report this case with a brief review of literatures.

Treatment of Malignant Gastroduodenal Obstruction with Using a Newly Designed Complex Expandable Nitinol Stent: Initial Experiences

PURPOSE: We wanted to evaluate the usefulness of a new type of a complex expandable nitinol stent that was designed to reduce the stent's propensity to migration during the treatment of malignant gastroduodenal obstructions. MATERIALS AND METHODS: Two types of expandable nitinol stent were constructed by weaving a single thread of 0.2 mm nitinol wire in a tubular configuration: an uncovered stent 18mm in diameter and a covered stent 16mm in diameter. Both ends of the covered stent were fabricated by coaxially inserting the covered stent into the tubular uncovered stent and then attaching the two stents together with using nylon monofilament. Under fluoroscopic guidance, the stent was placed in 29 consecutive patients (20 men and 9 women, mean age: 65 years) who were suffering with malignant gastric outlet obstruction (n=20), duodenal obstruction (n=6) or combined obstruction (n=3). Clinical improvement was assessed by comparing the food intake capacity before and after the procedure. The complications were investigated during the follow up period. RESULTS: Stent placement was successful in all the patients. After stent placement, the symptoms improved in all but one patient. During the follow up, stent migration occurred in one patient (3%) at 34 days after the procedure. Despite the stent migration, the patient was able to resume a soft diet. Six patients developed recurrent symptoms of obstruction with tumor overgrowth at a mean of 145 days after the procedure; all the patients underwent coaxial placement of an additional stent with good results. One patient showed recurrence of obstruction due to tumor in-growth, and this was treated by placement of a second stent. Two patients with stent placement in the duodenum suffered from jaundice 26 days and 65 days, respectively, after their procedures. CONCLUSION: Placement of the newly designed complex expandable nitinol stent seems to be effective for the palliative treatment of malignant gastroduodenal obstructions. The new stent also seems to help overcome the disadvantage of the increased migration observed for the covered stent.

CT Findings of Gastrointestinal Stromal Tumor versus Lymphoma of the Small Intestine

PURPOSE: To compare CT features of gastrointestinal stromal tumors (GIST) with those of lymphomas in the small intestine. MATERIALS AND METHODS: CT findings of 11 pathologically confirmed GIST patients and 10 lymphoma patients were retrospectively reviewed. CT findings were analyzed with regard to location, size, margin, growth patterns, internal character, enhancement, invasion, vascular encasement, lymphadenopathy, intestinal obstruction and ascites. RESULTS:An extraluminal mass was present in 82% (9/11) of the GIST patients versus 30% (3/10) of the lymphoma patients. Circumferential wall thickening was observed in 80% (8/10) of the lymphoma patients (p.05). CONCLUSION: Features revealed by CT scans are highly useful in differentiating GIST from lymphoma of the small intestine. Extraluminal growth and internal necrosis or gas are more common in patients with GIST compared with lymphoma. CT features of circumferential wall thickening and associated lymphadenopathy are more common in patients with lymphoma.

Radiologic Findings of Extraosseous Ewing's Sarcoma

PURPOSE: The purpose of this study is to evaluate the radiologic findings of the extraosseous Ewing's sarcoma. MATERIALS AND METHODS: Six patients with pathologically confirmed extraosseous Ewing's sarcoma were retrospectively reviewed. Patients included two men and four women with an average age of 21.5 years (age range 9-48 years). Plain radiographs (six patients), magnetic resonance (MR) images (five patients), computed tomographic (CT) scans (three patients) and whole body scintigraphy (two patients) were reviewed and analyzed. Images were evaluated with regard to lesion location, size, margin, muscle or bone involvement and intrinsic imaging characteristics on CT and MRI. RESULTS:The tumors were located in the thigh (three patients), back (two patients) and upper arm (one patient). The tumors ranged in size from 2.3 cm to 7.5 cm (mean, 5.2 cm), were mainly well circumscribed and showed no evidence of calcification prior to treatment. Margins were well defined in four out of the six patients. Four patients had subcutaneous lesions and the other two patients had intramuscular lesions. Muscle (two patients) and bone invasion (one patient) were present. The masses were heterogenous low signal intensity on T1 weighted images and heterogeneous high signal intensity on T2 weighted images compared with muscle. Heterogeneous enhancement within the lesion was observed in all patients on CT and MRI. Whole body scintigraphy using Tc-99 m MIBI showed increased uptake in the masses of two patients. CONCLUSION: Extraosseous Ewing's sarcomas were frequently seen as a well-circumscribed ovoid mass with nonspecific findings on CT and MRI. Despite being a relative rare tumor, it should be included in the differential diagnosis of a non-calcified soft-tissue mass, especially in subcutaneous tissue.