Abnormalities of the hands during the blood-pool phase of skeletal scintigraphy

Abstract

A 12-year-old boy with renal adenocarcinoma presented for follow-up metastatic evaluation by skeletal scintigraphy. After nephrectomy, he had been treated with doxorubicin, dactinomycin, vincristine, and cyclophosphamide. He had been staged preoperatively and at one year postoperatively by bone scintigraphy; both previous studies were unremarkable. Incidental triplephase images of the hands were obtained subsequent to injection on the dorsum of the left hand, prompted by a futile search for accessible veins of both upper extremities (Fig 1). There are four possible explanations of the abnormal finding depicted in Fig 1. Three of the four considerations are: adherence of the radiopharmaceutical to chemically traumatized venous endothelium, secondary to chemotherapy; adherence of the radiopharmaceutical to mechanically traumatized venous endothelium, secondary to a recent indwelling venous catheter; or thrombophlebitis, secondary to one of the first two possibilities. Intravenous administration of doxorubicin, dactinomycin, and vincristine, the three chemotherapeutic agents which had been used to treat this patient, can be complicated by soft-tissue inflammatory reactions. 1'2 However, the patient had received none of these medicines for the past year. The patient had had no indwelling catheter for the past year and had no current symptoms or signs of thrombophlebitis. Hence, the probability that the abnormal finding could be attributable to an artifact from a catheter is unlikely. Having eliminated the first two possible explanations, the third explanation is likewise discounted. Because of the patient's generalized weakness, imaging began 15 seconds after the patient was injected while he was seated in a wheelchair with subsequent placing of hands on camera surface. An arterial-phase image was acquired, that initially and incidentally recorded the venous phase, which demonstrated gradual clearance by the basilic vein and slower clearance by the cephalic vein via the dorsal rete (Fig 2). The literature is replete with articles reporting blood-pool images of the hands subsequent to arterial-phase imaging. We are unaware of any reports of direct evaluation of venous drainage of the hands, which would of course require venipuncture of the hand. The recording of venous clearance in our patient was mere happenstance and provided an initially vexing blood-pool image. In the osseous-phase image in this patient, the venipuncture artifact persisted, but the curvilinear abnormality was no longer demonstrated. We conclude that the blood-pool image (Fig 1) represents normal venous clearance in the unfamiliar setting of hand injection. First-pass and osseous-phase imaging of various skeletal sites has been widely used in resolving a variety of clinical questions. However, image acquisition during the blood-pool phase was not widely employed until it was reported within the context of triple-phase scintigraphy, popularized recently in the differentiation of cellulitis from underlying osteomyelitis. Because osteomyelitis of the hands and wrists is infrequent in contrast to its more frequent suspicion involving the lower extremities and pelvis, few reports of blood-pool imaging of the hands have been generated. However, a wide variety of lesions of the hands, particularly neurovascular instability, have been reported, as reflected in the following gamut.