Daniel Picard

Tc-99m sestamibi and other agents in the detection of metastatic medullary carcinoma of the thyroid.

The 10-year survival rate for medullary carcinoma of the thyroid (MCT) is 50%; thus, good tumor-seeking radiopharmaceuticals are needed to localize foci of recurrence and metastasis during follow-up. Two patients with metastatic MCT were studied with Tl-201, l-131 MIBG, Tc-99m (V)-DMSA, and Tc-99m MIBI. A SPECT study with the latter agent allowed the visualization and precise localization of a metastatic mediastinal lymph node. More studies need to be done to evaluate the role of Tc-99m MIBI in the detection of recurrence and metastases of MCT.

Normal Parathyroid Function with Decreased Bone Mineral Density in Treated Celiac Disease

Decreased bone mineral density (BMD) has been reported in patients with celiac disease in association with secondary hyperparathyroidism. The present study investigated whether basal parathyroid hormone (PTH) remained elevated and whether abnormalities of parathyroid function were still present in celiac disease patients treated with a gluten-free diet. Basal seric measurements of calcium and phosphate homeostasis and BMD were obtained in 17 biopsy-proven patients under treatment for a mean period of 5.7+/-3.7 years (range 1.1 to 15.9). In addition, parathyroid function was studied with calcium chloride and sodium citrate infusions in seven patients. Basal measurements of patients were compared with those of 26 normal individuals, while parathyroid function results were compared with those of seven sex- and age-matched controls. Basal results were similar in patients and controls except for intact PTH (I-PTH) (3.77+/-0.88 pmol/L versus 2.28+/-0.63 pmol/L, P<0.001), which was higher in the former group but still within normal limits. Mean 25-hydroxy vitamin D and 1,25-dihydroxy vitamin D values were normal in patients. Parathyroid function results were also found to be similar in both groups. Compared with a reference population of the same age (Z score), patients had significantly lower BMDs of the hip (-0.60+/-0.96 SDs, P<0.05) and lumbar spine (-0.76+/-1.15 SDs, P<0.05). T scores were also decreased for the hip (-1.3+/-0.9 SDs, P<0.0001) and lumbar spine (-1.4+/-1.35 SDs, P<0.0001), with two to three patients being osteoporotic (T score less than -2.5 SDs) and seven to eight osteopenic (T score less than -1 SDs but greater than or equal to -2.5 SDs) in at least one site. Height and weight were the only important determinants of BMD values by multivariate or logistical regression analysis in these patients. The results show higher basal I-PTH values with normal parathyroid function in treated celiac disease. Height and weight values are, but I-PTH values are not, an important determinant of the actual bone mass of patients. Normal parathyroid function in treated patients suggests a lack of previous severe secondary hyperparathyroidism and/or complete adaptation to prior changes in parathyroid function.

Localization of abnormal parathyroid gland(s) using thallium-201/iodine-123 subtraction scintigraphy in patients with primary hyperparathyroidism.

TI-201/1-123 subtraction scintigraphy was performed in 17 patients with clinical symptoms and biochemical measurements suggestive of primary hyperparathyroidism. Nineteen abnormal sites were identified. These results were correlated with PTH measurements and surgical findings. Three sites were considered unrelated to the parathyroid glands, two corresponding to palpable thyroid nodules and one to muscle uptake of unknown origin. One scintigram did not reveal either of two abnormal glands while two others were considered falsely positive in view of surgical failure. Fourteen sites corresponded to abnormal parathyroid gland at surgery; five glands, weighing more than 2000 mg, could be correctly located on the TI-201 scintigraphy prior to the subtraction procedure; six glands, weighing between 500 and 2000 mg, were easily localized after the subtraction procedure; three glands, weighing between 180 and 200 mg, were correctly localized after further manipulation of the subtraction procedure. In a patient with parathyroid hyperplasia, one gland, weighing 150 mg, was not located and another was not found upon surgery. Overall sensitivity was 87.5%. A positive correlation between PTH levels, tumor weight, and ease of detection on scintigraphy was found. This correlation was particularly useful in excluding large abnormal uptake related to thyroid disorder or artifact. The results suggest that TI-201/1-123 parathyroid scintigraphy could become an alternative to TI-201/Tc-99m parathyroid scintigraphy, with possibly improved detection of low weight abnormal parathyroid glands.

Gallium-67 imaging in pericarditis secondary to tuberculosis and histoplasmosis

In recent years, many case of Ga-67 uptake by the heart have been reported. One such case involved a patient with tuberculous pericarditis.1 Recently, a patient was referred to us for the investigation of a fever of unkown origin. A Ga-67 scan was performed and showed an intense uptake by the pericardium. The final diagnosis was pericarditis secondary to mediastinal lymph node involvement with tuberculosis and histoplasmosis.

Spinal cerebrospinal fluid leak demonstrated by radioisotopic cisternography.

Many conditions are known to cause a cerebrospinal fluid (CSF) fistula; one of them is lumbar puncture for contrast myelography. Reported here is the case of a man who underwent contrast myelography at the L2-L3 level and who presented with postural headaches and lumbalgia with radiation to the legs three weeks after the procedure. Tc-99m albumin isotopic cisternography at the L5-S1 level was performed and clearly depicted a functional CSF leak through the dura at the L2-L3 level and CSF suffusion along several rachidian roots. Scinticisternography may thus be used to localize accurately a CSF leak.

Vascular complication of a transjugular intrahepatic portacaval stent

The percutaneous transjugular intrahepatic portacaval stent shunt is a nonsurgical approach to portosystemic shunting. The case of a large defect seen on a radiocolloid liver-spleen scan is attributed to a hepatic infarct related to the shunting procedure.

Abdominal Patterns of lndium-111 Labeled Leukocyte Imaging

ln-111 oxine WBC abdominal scanning is now a widely accepted technique for the detection of abdominal infectious processes. High sensitivity and specificity are achieved, ln-111 labeled leukocyte accumulation, however, does not always suggest the diagnosis of abscess. Higher specificity could be obtained by the knowledge of the ln-111 leukocyte distribution pattern in the abdomen in other pathologic states like 1) inflammation of abdominal wounds, stoma; 2) surgical complication without abscess formation; 3) inflammatory or ischemic bowel disease; or 4) swallowing leukocytes which subsequently are visualized in the intestinal lumen. One hundred fifty-two consecutive WBC scans performed over 18 months were reviewed and classified according to their pattern of uptake: 96 cases showed no abdominal uptake, and 56 had accumulation of leukocytes in the abdomen. Twenty-eight of these patients had proven abdominal abscess, and the remaining 26 were positive due to other causes. This report briefly discusses the distribution pattern of ln-111 labeled leukocytes in the latter patients and compares the results obtained using different diagnostic criteria.

Noninvasive diagnosis of Caroli syndrome associated with congenital hepatic fibrosis using hepatobiliary scintigraphy.

A patient who was studied for portal hypertension had an enlarged liver and multiple hepatic cysts on abdominal CT scan. He underwent hepatobiliary scintigraphy using Tc-99m mebrofenin which documented communication of the cysts with the main biliary tree and allowed a noninvasive diagnosis of Caroli syndrome associated with congenital hepatic fibrosis.

Demonstration of abnormal peritoneal communication in patients with ascites.

Patients with ascites are known to have complications such as pleural effusions and hernias. Special diagnostic procedures are occasionally necessary to determine the nature of the abnormality and to determine the corrective medico-surgical approach. The two cases described illustrate the usefulness of intraperitoneal as well as intrapleural injection of a radionuclide in diagnosing the leakage of ascitic fluid.