High predictive value of F-18 FDG PET patterns of the spine for metastases or benign lesions with good agreement between readers.

Two nuclear medicine physicians retrospectively evaluated fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) spine abnormalities in patients with cancer with the purpose of identifying straightforward criteria for benign versus malignant spine abnormalities. Four hundred seventy-five consecutive patients with colon, breast, and lung cancer were evaluated with FDG. Thirty-two patients (32) had spine abnormalities, 30 of 32 patients had adequate follow up for a final diagnosis, and 29 of 30 patients' studies were available to both PET readers for this retrospective review. The readers categorized the FDG PET abnormalities as benign, metastatic, or equivocal using a straightforward set of criteria. A final diagnosis was made using magnetic resonance imaging (MRI), computed tomography (CT), plain films, bone scans, previous studies, and clinical follow up. A single spinal focus of increased FDG activity had a relatively high probability of being a spinal metastasis (71%); and the more foci, the higher the probability. Segmental decreased activity of the spine after radiation therapy indicated benignity. The only discrepancies were with 3 abnormalities, each called metastasis by 1 reader and equivocal by the other, with a final diagnosis of metastasis in each case. Equivocal patterns required CT or MR correlation, because these could be either malignant or benign. However, abnormal patterns fulfilling either the benign or metastatic criteria described here resulted in the correct diagnoses of benign spinal changes or spinal metastases, respectively, in 100% of cases with low interobserver variation. No study was interpreted as benign by 1 reader and metastasis by the other. The 2 nuclear medicine readers agreed in their interpretations in 90% of cases.

Single photon emission computed tomography radionuclide ventriculography in the noninvasive diagnosis and evaluation of a false left ventricular aneurysm (pseudoaneurysm).

An inferior wall false aneurysm (pseudoaneurysm) was diagnosed in a 77-year-old male by single photon emission computed tomography (SPECT) radionuclide ventriculography (RNV). This immediately followed routine planar RNV because the latter did not lead to definitive characterization of the type of aneurysm and did not ideally characterize the location and size of the aneurysm. RNV was followed by false-negative first-pass radionuclide ventriculography, routine echocardiography, and gated magnetic resonance imaging of the heart (cardiac MRI). A definitive diagnosis of a false aneurysm is found at surgery and pathology; however, the patient declined surgery and has done well for 1.5 years after these imaging studies. The first-pass study is limited with relatively small pseudoaneurysms, like in this case. Echocardiography is noninvasive and can show wall motion and aneurysm size. Cardiac MRI is the most expensive noninvasive study but, in addition to revealing the diameters of the neck and body of the aneurysm, MRI is able to characterize the surrounding myocardium. This case report suggests the critical information needed for a confident, noninvasive diagnosis of false aneurysm can be obtained with SPECT RNV. The location of the aneurysm is easily determined, and the relative diameters of the neck to the body of the aneurysm can be easily seen. SPECT RNV is superior to planar RNV and first-pass radionuclide ventriculography in making a diagnosis of false aneurysm. Although RNV might be unable to directly demonstrate the perfusion and thickness of the myocardium, it has an advantage over MRI in terms of ejection fraction (EF) and cost.