Marc Coel

IMAGING OF STRESS INJURIES TO BONE: Radiography, Scintigraphy, and MR Imaging

Although conventional radiographs continue to be used as a primary method for the diagnosis of stress fractures, the limitations of radiography in early detection have been increasingly recognized. Advanced imaging techniques, including radionuclide methods, and more recently, MR imaging, have increasingly been employed in the assessment of stress fractures, and have provided valuable insights into the spectrum of stress-related changes to bone. This article reviews the diagnostic methods available to the clinician for detection of stress injuries to bone.

Reduction of Myocardial 2-Deoxy-2-[18F]Fluoro- D-Glucose Uptake Artifacts in Positron Emission Tomography Using Dietary Carbohydrate Restriction

PURPOSE The use of carbohydrate restriction prior to 2-deoxy-2-[18F] positron emission tomography (FDG-PET) to reduce image artifacts caused by myocardial FDG uptake was investigated. PROCEDURES Ninety-six whole-body FDG-PET scans were studied. Dietary intake of the meal prior to scanning was recorded. Coronal and transverse images were assessed visually and scored based on myocardial FDG uptake and the presence of associated image artifacts. RESULTS Of 49 patients who consumed carbohydrates prior to PET, 14 (28.6%) had a clinically significant image artifact versus only five (10.6%) of 47 patients who did not consume carbohydrates (P = 0.0275). A 3.36 times increased risk (confidence interval 1.00-12.97) for clinically significant image artifacts was calculated for patients who consume carbohydrates in their last meal prior to scanning. CONCLUSIONS With the rising use of FDG-PET in the evaluation of intra-thoracic malignancies, dietary carbohydrate restriction prior to scanning may play a role in increasing lesion detectability and reducing false negative scans.

1. Positron Emission Tomography of Thoracic Malignancies. Reduction of Myocardial Fluorodeoxyglucose Uptake Artifacts With a Carbohydrate Restricted Diet.

Purpose: To reduce the artifact caused by cardiac uptake of F-18 fluorodeoxyglucose (FDG); we investigated the change in myocardial FDG uptake after placing a group of patients on a carbohydrate-restricted diet.Methods: Case control study involving 130 whole body FDG PET scans. 73 scans were of patients on carbohydrate-restriction; the remaining 57 were without dietary restrictions. Dietary intake for the last meal prior to scanning was recorded for both groups. Coronal and axial images were assessed and scored based on myocardial FDG uptake the presence of associated image artifacts.Results: Of the 73 patients on the diet, 50 did not consume carbohydrates, while of the 57 patients without dietary restriction, 13 did not consume carbohydrates. Of the 67 patients from both groups who consumed carbohydrates prior to their PET scan, 17 (25.4%) had a clinically significant image artifact versus only 6 (9.5%) of the 63 patients who did not consume carbohydrates (P = 0.018) in their meals prior to scanning. The odds ratio was calculated to be 3.23 (confidence interval 1.09-10.00), indicating that the risk a clinically significant image artifact will occur is 3.23 times higher for patients who consume carbohydrates in their last meal prior to scanning.Conclusion: A substantial reduction in the prevalence of myocardial FDG uptake image artifacts among patients who did not consume carbohydrates was observed. A carbohydrate dietary restriction prior to scanning may play a significant role in increasing lesion detectability and in preventing false negative scans when imaging for thoracic neoplasm.

Current imaging and possible therapeutic management of glucagonoma tumors: a case report.

Glucagonomas, like other neuroendocrine tumors, express somatostatin receptors in more than 80% of cases. Unfortunately, because of the rarity of these tumors, the sensitivity and specificity of somatostatin analog (octreotide) imaging have not been established. Nonetheless, there have been limited reports in the literature supporting the use of indium In-111 DTPA N-terminal D-phenylalanine (D-PHE1) octreotide for glucagonoma imaging and may be most beneficial as an adjuvant to conventional imaging for tumor staging and therapeutic decision making. Current therapeutic applications of octreotide focus on stabilization of disease in tumors expressing somatostatin receptors, and tumor destruction, using beta-emitting isotopes. In this report, imaging of a glucagonoma with In-111 DTPA-D-PHE1 octreotide scintigraphy is described in a 51-year-old woman examined for a large palpable abdominal mass.

Preoperative lymphoscintigraphy in the evaluation of squamous cell cancer of the vulva

PURPOSE A pilot study was undertaken to determine the lymphatic drainage of vulvar cancer using cutaneous lymphoscintigraphy. METHODS Six patients with biopsy-proved T1 squamous cell cancer of the vulva were studied using 0.4 to 0.6 mCi Tc-99m HSA. Planar imaging was performed after patients received intradermal injections of Tc-99m HSA in a total volume of 0.4 ml at four sites around the vulvar lesion. RESULTS Tumor locations included two midline lesions and three anterior third lesions. One tumor was located in the midthird of the labia majora. There was no clinically suspicious inguinal adenopathy in any patient. Based on classic anatomic descriptions of cutaneous lymphatic drainage, all but one patient would have been predicted to have drainage to both inguinal nodal basins. Cutaneous lymphoscintigraphy was successful in all six patients. Unilateral drainage was shown in five of six patients. Only one patient had bilateral inguinal drainage, and her tumor was located in the left anterior third of the labia minora. CONCLUSIONS Cutaneous lymphoscintigraphy with Tc-99m HSA is easily performed and may be potentially useful in defining lymphatic basins at risk in squamous cell cancer of the vulva.

Pulmonary embolism from a popliteal vein aneurysm

This is the first report of a venous aneurysm detected by radionuclide venography. Aneurysms of the popliteal vein are very rare. Described here is a case of a saccular popliteal venous aneurysm that presented as dyspnea secondary to pulmonary embolism. In this case, there was recurrent PE despite anticoagulant therapy. Almost all such aneurysms are associated with PE, about half of which are recurrent. This report demonstrates another useful aspect of obtaining a simultaneous radionuclide venogram when performing a perfusion lung scan with Tc-99m MAA.

Detection of synchronous primary breast and prostate cancer by F-18 fluorocholine PET/CT.

Abstract:There is growing experience with F-18 fluorocholine (FCH) for positron emission tomography/computed tomography (PET/CT) imaging of prostate cancer, but limited experience in breast cancer. We report the PET detection of synchronous cancers of the breast and prostate. A 68-year-old man with

Heat-damaged red cell scan for intraoperative localization of the accessory spleen

Destruction of platelets by the reticuloendothelial system in immune thrombocytopenia purpura (ITP) is enhanced by platelet-associated IgG. Relapse after splenectomy may result from IgG produced in the accessory spleen. These structures may be located at any site between Gerotas fascia and the left ovary or testicle as well as adjacent to the spleen. The heat-damaged red cell scan (HDRCS) has been demonstrated to be an accurate method for identifying accessory spleens. HDRCS using semi-in vitro labeling of the patients red blood cells with technetium 99m pertechnetate delineated accessory splenic tissue as the etiology of post-splenectomy relapse three times in two patients 3 to 9 months postoperatively. A labeled intraabdominal probe and HDRCS were subsequently used by the surgical team for identification and excision of the accessory spleen. Four additional patients underwent splenectomy for ITP between 1989 and 1992; heat-damaged red blood cells were injected after the major splenic tissue was removed. Accessory spleens were identified in two patients. All patients were discharged within 6 days, without perioperative complications. Two patients currently require steroids. The techniques of intraoperative HDRCS allow rapid localization and removal of the accessory spleen at the time of laparotomy. Evidence of growth of accessory splenic tissue postsplenectomy was demonstrated.

Correlation of single photon emission computed tomography parameters as a noninvasive alternative to liver biopsies in assessing liver involvement in the setting of HIV and hepatitis C virus coinfection: A multicenter trial of the adult aids clinical trials group

Performing a liver biopsy in patients infected with HIV and hepatitis C virus (HCV) is considered the standard of practice to assess hepatic involvement but carries risks to patients. This pilot study was designed to identify single photon emission computed tomography (SPECT) parameters that correlate with liver disease stage. HIV-coinfected and HCV-coinfected individuals undergoing a liver biopsy had a SPECT scan performed. The results showed that a number of SPECT parameters were associated with histologic changes in architecture, fibrosis, and cirrhosis, of which two SPECT parameters, the minimum pixel count for spleen region of interest and maximum pixel count for right hepatic lobe, correctly classified 39 of 46 SPECT/biopsy pairs. In conclusion, this pilot trial identified SPECT parameters that correlated with liver histology changes. A larger study is needed to demonstrate whether SPECT parameters alone or with other markers can provide information on fibrosis with the clinical significance obtained through liver biopsy.

Two meningiomas detected incidentally by Tc-99m HDP bone scintigraphy during a work-up for breast cancer.

A 64-year-old woman was diagnosed with infiltrating ductal carcinoma of the left breast by needle biopsy. Results of a Tc-99m HDP bone scan were normal, except for two areas of increased uptake in the head-one in the left posterior frontal bone and the other in the left sphenoid wing. These findings were investigated further. A plain film study showed a blastic abnormallty in the left posterior frontal area. An MRI confirmed two contrast-enhancing lesions adjacent to bone, corresponding to the abnormalities on the bone scans. The findings are consistent with benign meningiomas. The patient subsequently underwent a left modified radical mastectomy. If the lesions on bone scan had not been further evaluated, the patients cancer would have been categorized stage IV instead of stage I (T1N0M0), which carries a much better prognosis. The patient continues to remain free of neurologic symptoms, so surgery is not being considered at this time.