Risks associated with magnetic resonance imaging and cervical collar in comatose, blunt trauma patients with negative comprehensive cervical spine computed tomography and no apparent spinal deficit.

INTRODUCTION: In blunt trauma, comatose patients (Glasgow Coma Scale score 3 to 8) with a negative comprehensive cervical spine (CS) computed tomography assessment and no apparent spinal deficit, CS clearance strategies (magnetic resonance imaging [MRI] and prolonged cervical collar use) are controversial. METHODS: We conducted a literature review to delineate risks for coma, CS instability, prolonged cervical collar use, and CS MRI. RESULTS: Based on our search of the literature, the numbers of functional survivor patients among those who had sustained blunt trauma were as follows: 350 per 1,000 comatose unstable patients (increased intracranial pressure [ICP], hypotension, hypoxia, or early ventilator-associated pneumonia); 150 per 1,000 comatose high-risk patients (age > 45 years or Glasgow Coma Scale score 3 to 5); and 600 per 1,000 comatose stable patients (not unstable or high risk). Risk probabilities for adverse events among unstable, high-risk, and stable patients were as follows: 2.5% for CS instability; 26.2% for increased intensive care unit complications with prolonged cervical collar use; 9.3% to 14.6% for secondary brain injury with MRI transportation; and 20.6% for aspiration during MRI scanning (supine position). Additional risk probabilities for adverse events among unstable patients were as follows: 35.8% for increased ICP with cervical collar; and 72.1% for increased ICP during MRI scan (supine position). CONCLUSION: Blunt trauma coma functional survivor (independent living) rates are alarming. When a comprehensive CS computed tomography evaluation is negative and there is no apparent spinal deficit, CS instability is unlikely (2.5%). Secondary brain injury from the cervical collar or MRI is more probable than CS instability and jeopardizes cerebral recovery. Brain injury severity, probability of CS instability, cervical collar risk, and MRI risk assessments are essential when deciding whether CS MRI is appropriate and for determining the timing of cervical collar removal.

Impact of three-phase bone scintigraphy on the diagnosis and treatment of complex regional pain syndrome type I or reflex sympathetic dystrophy.

OBJECTIVE: To determine the impact of three-phase bone scintigraphy (TPBS) on the diagnosis and management of complex regional pain syndrome type I (CRPSI) or reflex sympathetic dystrophy (RSD). SUBJECTS AND METHODS: Twenty consecutive patients with a recent clinical evidence of CRPSI were referred for TPBS as part of their routine management plan. All patients underwent neurological examinations with special attention to the evaluation of clinical features of vasomotor, sudomotor, motor and sensory dysfunction. Patients were followed prospectively. When both the clinical and TPBS results supported the diagnosis of CRPSI, patients were started on treatment. RESULTS: Of the 20 patients, TPBS supported the diagnosis of RSD in 9 who were treated with steroids and physiotherapy. Complete follow-up was available for 7 of them and all had a satisfactory response to treatment. For the remaining 11 patients RSD was diagnosed clinically but not confirmed by TPBS. On follow-up there was no evidence that TPBS failed to identify RSD in these 11 patients. CONCLUSION: The results indicate that TPBS confirmed the clinical diagnosis of RSD, and, more importantly, had a significant impact on its management.

Renography within 1 hour of renal transplantation: technical feasibility and clinical utility.

OBJECTIVE: Renographies obtained within 1 h of renal transplantation were studied prospectively to evaluate their technical feasibility and potential clinical impact on successful treatment of immediate posttransplantation complications such as arterial or venous thrombosis, which require prompt diagnosis and management. SUBJECTS AND METHODS: During December 1996 to December 1998, 127 renal transplants were performed. Ninety-four patients had complete renographic studies within 1 h of surgery. It was not possible to perform renography on 26 patients who were not sent to the Department of Nuclear Medicine within 1 h of transplant and 7 other patients who could not undergo a complete renogram because of their postoperative condition. RESULTS: There was no complication attributed to transporting patients to the Department of Nuclear Medicine for these studies so soon after surgery. Of the 94 renographies obtained immediately following transplant surgery 46 were abnormal. However, when compared with the usual policy of obtaining baseline renograms between 12 and 72 h after surgery, treatment was changed for only 2 patients. Radionuclide renography within 1 h of transplant surgery was technically feasible. CONCLUSION: Based on the results of this study the clinical utility of obtaining renography within 1 h posttransplant was minimal and hence we recommended that it should not be performed routinely but could be used on an individual basis when imminent intervention is highly likely.

Technical errors in planar bone scanning.

Optimal technique for planar bone scanning improves image quality, which in turn improves diagnostic efficacy. Because planar bone scanning is one of the most frequently performed nuclear medicine examinations, maintaining high standards for this examination is a daily concern for most nuclear medicine departments. Although some problems such as patient motion are frequently encountered, the degraded images produced by many other deviations from optimal technique are rarely seen in clinical practice and therefore may be difficult to recognize. The objectives of this article are to list optimal techniques for 3-phase and whole-body bone scanning, to describe and illustrate a selection of deviations from these optimal techniques for planar bone scanning, and to explain how to minimize or avoid such technical errors.

Nonosseous abnormalities on bone scans.

Although bone scanning is a test primarily concerned with skeletal abnormalities, important nonosseous findings are occasionally present on the images. To gauge the significance of such nonosseous uptake and, in particular, to determine whether these findings contain useful diagnostic information, the technical and medical staff in nuclear medicine must recognize the various patterns of nonbony uptake and understand their causes. The objectives of this article are to demonstrate the appearances of nonosseous uptake on bone scans, to categorize the forms of soft-tissue uptake, to emphasize technical artifacts leading to soft-tissue uptake, and to highlight the clinical significance of pathologic soft-tissue uptake.

Dextrose solutions yield radiochemical impurities: the "sweet" scans.

OBJECTIVE: If additional chemicals are inadvertently introduced in the preparation of radiopharmaceutical kits, radiochemical impurities may be formed. We report our experience with erroneously diluting (99m)Tc-pertechnetate eluate with 5% dextrose solution rather than normal saline during the preparation of (99m)Tc-tetrofosmin, (99m)Tc-methylene diphosphonate (MDP), (99m)Tc-stannous colloid, and (99m)Tc-mebrofenin. METHODS: Scintigrams for 3 of the 4 radiochemicals unintentionally prepared with 5% dextrose were found to have an altered biodistribution. Therefore, radiopharmacy procedures for the day were reviewed, and instant thin-layer chromatography (ITLC) was performed. RESULTS: Scintigrams showed an altered biodistribution consistent with an impurity. Review of procedures that day uncovered the error of using 5% dextrose to dilute the (99m)Tc eluate. The altered biodistribution on (99m)Tc-stannous colloid, (99m)Tc-MDP, and (99m)Tc-mebrofenin scintigrams consisted of cardiac blood-pool activity (possibly as a result of slow clearance of (99m)Tc-dextrose), soft-tissue background activity (possibly as a result of interstitial distribution of (99m)Tc-dextrose), renal and bladder activity (possibly as a result of renal elimination of (99m)Tc-dextrose), and gallbladder activity (possibly as a result of hepatobiliary excretion of (99m)Tc-dextrose). Both scintigrams and ITLC showed no evidence of impurities for the (99m)Tc-tetrofosmin prepared using 5% dextrose. CONCLUSION: Unintended preparation of radiochemicals with 5% dextrose rather than normal saline often results in the production of impurities, possibly (99m)Tc-dextrose. Because some but not all commercial radiochemical kits prepared with 5% dextrose will suffer this fate, nuclear medicine physicians reviewing the day's images will be confronted with a confusing combination of expected and grossly abnormal findings.

Heterotopic ossification.

Heterotopic ossification (HO) is the presence of bone in soft tissue where bone normally does not exist. The acquired form of HO most frequently is seen with either musculoskeletal trauma, spinal cord injury, or central nervous system injury. For example, patients who have recently undergone total hip arthroplasty or have paraplegia after spinal cord injury are at risk for HO. The fever, swelling, erythema, and occasional joint tenderness seen in early HO can be difficult to distinguish from cellulitis, osteomyelitis, or thrombophlebitis. Bone scanning and other imaging tests frequently are used to distinguish between these diagnostic possibilities. As treatment or prophylaxis for HO, either a nonsteroidal antiinflammatory drug (such as indomethacin), a diphosphonate (such as ethane-1-hydroxy-1,1-diphosphate), or local radiation therapy is recommended. Before therapy begins, bone scanning may be requested to confirm the diagnosis of HO. In addition, surgical resection of HO is used to preserve joint mobility; however, HO is likely to recur and possibly progress if resection is undertaken before the lesion has become mature. With a view toward avoiding recurrent HO and other operative complications, serial quantitative bone scans are used as an aid to time surgical intervention.

An Unusual Stress Fracture Site: Midhumerus.

In brief A bodybuilder who reported left shoulder and upper arm pain was found to have a midhumeral stress fracture. Stress fractures are uncommon in non-weight-bearing bones, but a careful history that includes type, frequency, and duration of exercise can raise suspicion, and a physical examination, x-ray, and bone scan can detect the defects when they occur. Technetium bone scan can confirm injuries that are usually only suggested by x-rays.