Examination of pattern of RI accumulation in thyroid cartilage on bone scintigraphy.

OBJECTIVE: In bone scintigraphy, abnormal RI accumulation in ossified thyroid cartilage is often noted. However, because similar accumulation is also seen in tumor-involved cartilage, distinction between these two lesions is sometimes difficult. We examined the differences in RI accumulation by ossification of the thyroid cartilage and cartilage invasion with anterior, posterior, and oblique views of bone scintigraphy in this study. METHODS: This study included 120 patients (104 men, 16 women; mean age 67.8 +/- 9.6 years; range 48-90 years) with laryngeal or lower pharyngeal carcinoma. The patients had exhibited abnormal accumulation of RI on thyroid cartilage on bone scintigraphy between February 1999 and March 2007. We evaluated accumulation of thyroid cartilage in the anterior, posterior, and oblique views on bone scintigraphy. The presence/absence of tumor invasion of the thyroid cartilage was checked by comparing the findings of enhanced computed tomography and magnetic resonance imaging (MRI) as well as evaluating operative records. RI accumulation in thyroid cartilage was divided into four types (diffuse accumulation, intense diffuse accumulation, slight inhomogeneous accumulation, and intense inhomogeneous accumulation). RESULTS: Tumor invasion of thyroid cartilage was noted in 2 of the 42 patients with diffuse accumulation, 1 of the 18 patients with intense diffuse accumulation, 1 of the 38 patients with slight inhomogeneous accumulation, and 17 of 22 patients with intense inhomogeneous accumulation. Because the degree of tumor invasion was highest in cases in which bone scintigraphy revealed intense inhomogeneous accumulation of RI in the thyroid cartilage, we judged this pattern of RI accumulation to be an indicator of tumor invasion. When diagnosis was based on this criterion, positive predictive value, negative predictive value, and accuracy were 77%, 96%, and 93%, respectively (P < 0.0001, Chi-square test). CONCLUSIONS: The findings of this study suggest that ossification of thyroid cartilage can be distinguished from tumor-involved thyroid cartilage on the basis of the pattern of abnormal RI accumulation in the thyroid cartilage in patients with head/neck cancer.

Evaluation of diagnostic abilities of Ga-SPECT for head and neck lesions.

OBJECTIVE: Single-photon emission computed tomography (SPECT) using gallium (Ga) has been frequently used for diagnosing head and neck tumors in patients. Although the usefulness of Ga-SPECT is well known, the degree of the increase in diagnostic ability with Ga-SPECT for head and neck tumors has not been reported. We compared the ability of the planar images of Ga scintigraphy, SPECT images of Ga scintigraphy, and CT images to diagnose head and neck primary tumors and neck metastases. METHODS: The subjects of this study were 167 patients with malignant head/neck lesions. For Ga scintigraphy, Ga-67-citrate (74 MBq) was injected via a cubital vein. Planar and SPECT images were taken 72 h after the Ga-67-citrate injection. The rate of detection of the primary lesions was compared first between SPECT and planar images then between SPECT and CT images. The rate of detection for each stage of disease according to the TNM classification was also analyzed. RESULTS: The rate of detection of primary lesions was 50% with planar imaging and 69% with SPECT. And similarly, regarding the rate of detection of lymph node metastases, there was a significant difference between planar imaging and SPECT. The rate of detection of primary lesions was 70% for both CT and SPECT. At T stage, the rates of detection of primary lesions with each imaging technique were 11% with planar imaging and 39% with SPECT, and 22% with CT for stage T1. CONCLUSIONS: This study revealed the marked superiority of SPECT images over planar images in terms of the ability to detect primary tumors and tumor metastasis to cervical lymph nodes. Furthermore, the primary T1 tumor detection rate of SPECT images was higher than that of CT images. On the basis of these results, the concomitant use of SPECT is highly recommended when Ga scintigraphy is performed to check for malignant head/neck tumors.

A case of cavernous hemangioma in which malignancy was preoperatively excluded by FDG-PET.

A contrast-enhanced mass was revealed by computed tomography and magnetic resonance imaging in the left pelvic cavity of a 71-year-old man. Although the mass appeared to be a cavernous hemangioma, malignancy could not be ruled out. Abdominal angiography was performed but failed to rule out malignancy because it revealed vascular dislocation and encasement. (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) was then performed, and suggested a benign tumor, with a standardized uptake value (SUV) of 1.7. Following this finding, because the tumor was large and rupture could not be ruled out, we decided to perform surgery. The resected tumor was a benign cavernous hemangioma, consistent with the result obtained by FDG-PET.

Gallium scintigraphy in a case of tuberculous trochanteric bursitis.

We report a 67-year-old woman with systemic lupus erythematosus and systemic disseminated tuberculosis affecting the femoral trochanteric bursae, a site rarely affected by tuberculosis. For quantification of the inflammation with gallium-67 scintigraphy, we calculated the radioisotope count ratio in the most inflamed areas, the right lateral thorax and bursa of the right greater trochanter. Systemic scanning with this modality allowed evaluation of the extent of lesions and simple quantitative determination of the severity of inflammation, yielding information useful for the follow-up of the patient during the course of tuberculosis treatment.

Detection of local residual tumor after laryngeal cancer treatment using FDG-PET.

OBJECTIVE: Fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) is sometimes used as a means of follow-up after diagnosis and treatment of cancers of the head and neck region. The present study was undertaken to evaluate the ability of FDG-PET to detect local residual tumor after treatment of laryngeal cancer. METHODS: Thirty-six patients with laryngeal cancer underwent FDG-PET before and after initial treatment. Of these patients, 20 received FDG-PET before treatment and 28 received it after treatment. The relationship between standardized uptake values (SUV) and the presence or absence of local residual tumor was investigated by setting the cut-off value of the SUV using the receiver operating characteristics (ROC) curve. RESULTS: When the pre-treatment SUV threshold for laryngeal cancer was set at 7.20, the detection of local residual tumor after treatment using FDG-PET had a sensitivity of 77.78%, specificity of 81.82%, false positive rate of 18.18%, false negative rate of 22.22%, accuracy of 80% and a p value of 0.02. When the post-treatment SUV threshold for the larynx was set at 3.35, the test had a sensitivity of 93.75%, specificity of 91.67%, false positive rate of 8.33%, false negative rate of 6.25%, accuracy of 92.86% and a p value of 0.0001. CONCLUSIONS: FDG-PET was found to be useful for determining the presence of local residual tumor after treatment of laryngeal cancer.

Distinguishing benign from malignant gallbladder wall thickening using FDG-PET.

OBJECTIVE: Because thickening of the gallbladder wall is observed not only in patients with gallbladder cancer but also in those with benign diseases such as chronic cholecystitis and gallbladder adenomyosis, it is difficult to distinguish between benign and malignant gallbladder wall thickening by conventional techniques of diagnostic imaging such as computed tomography (CT), magnetic resonance imaging (MRI), and abdominal ultrasonography (US). In the present study, we attempted to distinguish between benign and malignant gallbladder wall thickening by means of fluorine-18-fluorodeoxyglucose (FDG)-Positron emission tomography (PET). METHODS: FDG-PET was performed in 12 patients with gallbladder wall thickening detected by CT or US, to determine whether it was benign or malignant. Emission scans were taken, beginning 45 minutes after intravenous administration of FDG, and SUV was calculated as an indicator of glucose metabolism. RESULTS: Of the 12 patients, 4 showed positive uptake of FDG in the gallbladder wall. Of these 4 patients, 3 had gallbladder cancer. The remaining one, who had chronic cholecystitis, had false-positive findings. The other 8 patients had negative uptake of FDG in the gallbladder wall. Two of these 8 underwent surgical resection, which yielded a diagnosis of chronic cholecystitis. The other 6 patients exhibited no sign of gallbladder malignancy and have been followed without active treatment. CONCLUSIONS: FDG-PET appears able to distinguish between benign and malignant gallbladder wall thickening.

A case of diffuse hepatic angiosarcoma diagnosed by FDG-PET.

A 76-year-old woman was admitted to our hospital with a 2-month history of increasing abdominal distension, leg edema, and dyspnea. The serum transaminase level was about twice the upper limit of normal. The CT showed no tumor. Fluorine-18 2-deoxy-2-fluoro-D-glucose (FDG)-positron emission tomography (PET) showed diffuse abnormal accumulation throughout the entire liver. She was diagnosed by histopathological examination as having hepatic angiosarcoma causing veno-occlusive disease (VOD). This is the first report of hepatic angiosarcoma with FDG-PET.

Natural history of major complications in hepatitis C virus-related cirrhosis evaluated by per-rectal portal scintigraphy.

AIM: To examine the correlation between the porto-systemic hypertension evaluated by portal shunt index (PSI) and life-threatening complications, including hepatocellular carcinoma (HCC), liver failure (Child-Pugh stage progression), and esophagogastric varices. METHODS: Two hundred and twelve consecutive subjects with HCV-related cirrhosis (LC-C) underwent per-rectal portal scintigraphy. They were allocated into three groups according to their PSI: group I, PSI< or =10%; group II, 10%

Splenic accumulation of Tc-99m HMDP in a patient with severe alcoholic cirrhosis of the liver.

The authors report unusual splenic accumulation of Tc-99m hydroxymethylene diphosphonate (HMDP) on bone scintigraphy of a patient with alcoholic cirrhosis of the liver. Laboratory studies showed hemolytic anemia and hemochromatosis resulting from alcohol abuse, both of which are thought to be related to the diffuse splenic uptake observed. When diffuse splenic accumulation by Tc-99m HMDP is seen, the existence of alcoholic hepatopathy might be considered.

A case of small cell carcinoma of the esophagus detected incidentally by FDG-PET.

Small cell carcinoma (SmC) of the esophagus is rare, and is sometimes impossible to detect by macroscopic inspection using an endoscope or histological examination of biopsied specimens. A 73-year-old man received F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) to evaluate the response to radiofrequency thermal ablation therapy for lung cancer. FDG-PET showed abnormal accumulation in the posterior mediastinum. Endoscopy disclosed ulcerous lesions with marginal elevation in the middle segment of the esophagus, but the biopsy specimen taken concurrently was not malignant histologically. FDG-PET, performed two months later, revealed abnormal accumulation in the suspect area, and the extent of accumulation was wider than previously. Histological examination of the specimen biopsied during the endoscopy led to a diagnosis of SmC. FDG-PET thus proved useful in the early detection of SmC.