Upper extremity radionuclide bone imaging: the wrist and hand.

Bone scintigraphy of the hands and wrists represents an important adjunct imaging technique that complements plain film radiographic examination. The use of the three-phase bone scan provides clinical information not only regarding osseous uptake but the blood flow and extravascular distribution of the radiotracer as well. Scintigraphic evaluation of the hands and wrists is employed in acute and chronic conditions. In the event of an equivocal or negative plain film, the bone scan can identify occult fractures. Of particular concern is the identification of scaphoid fractures due to the higher incidence of osteonecrosis. Work related injuries represent a significant health issue. The bone scan can be a part of the algorithm for evaluating chronic pain syndromes including reflex sympathetic dystrophy. The complimentary roles of bone scanning and imaging with gallium-67 citrate or radiolabeled leukocytes has proven useful in the evaluation of acute or chronic osteomyelitis. In addition, the diphosphonates are useful in identifying solitary and multiple primary bone tumors. In the case of primary bone tumor, thallium-201 can be used to evaluate response to therapy. Although uncommon in the hand and wrist, the bone scan can identify metastatic tumors or tumor-related conditions such as hypertrophic osteoarthropathy. Finally, bone scintigraphy may be useful in identifying location and extent in a variety of conditions such as fibrous dysplasia, histiocytosis X, and Paget's disease.

Staging of non-small cell bronchogenic carcinoma. Relationship of the clinical evaluation to organ scans.

Organ scans are generally performed on patients with bronchogenic carcinoma only when clinical evaluation is suspicious for metastases. However, it is not clear whether the clinical abnormalities will direct attention to the single organ which should be scanned, or if all three organs (bone, brain, liver) should be evaluated if any clinical abnormality is present. We investigated the use of triple organ radionuclide scanning and computerized tomography (CT) of the brain in the initial staging of patients with non-small cell bronchogenic carcinoma with no obvious metastases. Of 122 patients with newly diagnosed lung cancer, 53 met our criteria for further study. Thirty-three (62 percent) of these had at least one clinical abnormality suggestive of metastasis. Bone scanning detected metastases in seven (21 percent) and head CT in two additional patients (6 percent). Brain and liver scanning had no yield. In only five of these nine patients did the clinical abnormality direct attention to the organ with detectable metastases. Twenty of the 53 (38 percent) patients had a negative routine clinical evaluation, yet bone scanning showed metastases in three (15 percent). We concluded that clinical abnormalities are not specific for the organ in which metastases may be detected, so three scans (bone, liver, CT of the brain) should be obtained if there is any suspicion of metastasis based on history, physical examination, and laboratory tests. The value of bone scanning in clinically normal patients deserves further study.

Mediastinal impressions on the dilated esophagus.

This article explores how the mediastinum accommodates a significantly dilated esophagus, using achalasia as an anatomic model. This accommodation introduces the concepts of vascular tethering and the paratracheal esophagus as part of a unifying theory of "the path of least resistance." Practical examples demonstrate the importance of understanding these concepts in any disease involving esophageal dilatation.

Detection of motion in hybrid PET/SPECT imaging based on the correlation of partial sinograms.

This paper describes a motion detection method specific to hybrid positron emission tomography/single photon emission computed tomography systems. The method relies on temporal fractionation of the acquisition into three data sets followed by an algorithm based on the cross correlation (CC) of partial sinograms from successive sets at different rotations of the camera. Spatial inconsistencies due to motion are detected by decreases in the CC between two sets. This permits to separate data into premotion and postmotion sets of consistent data that are reconstructed independently then registered and summed. Rigid motions greater than 1-cm translation or 10 degrees rotation were detected with this method from experimental data obtained by manually moving phantoms made of radioactive spheres as well as from a patient lung study corrupted by artificial motion. The different motion studies showed that the image contrast does not seem to be a limiting factor and that the motion is best detected when the gantry is parallel to the direction of motion. The registration and fusion of the reconstructed premotion and postmotion sets lead in all cases to a reduction of the motion artifacts and an increase in signal-to-noise ratio.

A prospective controlled study of diagnostic imaging for acute shin splints.

OBJECTIVE: The purpose of this prospective, observational study was to examine the relationship of clinical examination, plain radiograph (XR), triple-phase bone scan (TPBS), and magnetic resonance imaging (MRI) in the investigation of patients presenting with acute shin splints. METHODS: 23 subjects with exercise induced lower leg pain and diffuse tibial tenderness of less than 3 months' duration were recruited. Subjects were excluded if there was clinical evidence of compartment syndrome, muscle hernia, or stress fracture. Each subject underwent XR, TPBS, and MRI within 2 wk of physical examination. Four asymptomatic controls underwent TPBS and MRI. Clinical findings, XR, TPBS, and MRI findings were independently recorded using a consistent template and subsequently analyzed. A single consensus lesion was chosen that provided the greatest overlap and highest grade to allow comparison of clinical and imaging findings. Sensitivity and specificity were calculated from data relating to clinical findings and diagnostic imaging. RESULTS: Eighteen subjects had bilateral symptoms and five unilateral with a mean duration of symptom of 5.4 wk (+/- 3.5). Of 41 symptomatic lower legs, there were TPBS abnormalities in 36 and MRI findings in 34. Analysis of clinical findings to TPBS and MRI demonstrated a sensitivity and specificity of 84%, 33% and 79%, 33%, respectively. Assuming TPBS as the "gold-standard," MRI findings demonstrated a sensitivity of 95% and specificity of 67%. There was poor agreement between the grading of TPBS and MRI (k = 0.3). In the 5/46 asymptomatic limbs, 3/5 demonstrated uptake on bone scan and 4/5 signal change with MRI. Imaging abnormalities were similarly seen in the four control patients. CONCLUSIONS: MRI may be used rather than TPBS and radiographs for evaluating acute tibial pain in athletes where avoidance of radiation exposure is desirable. Similar sensitivity and specificity may be expected from both investigations; however, in the light of abnormal TPBS and MRI findings in control and asymptomatic limbs, we recommend further studies be performed to define the extent of nonpathological TPBS and MRI changes.

Computed radiography X-ray exposure trends.

RATIONALE AND OBJECTIVES: Computed radiography provides correct optical density on film, independent of the incident radiation exposure, but it can result in under- or overexposure of the imaging plate. In the current study, we evaluated the radiation exposure trends of computed radiography over a 2-year period for portable chest examinations to determine and compare the radiographic techniques of the computed radiography system relative to conventional screen-film detectors. METHODS: A Fuji computed radiography system was interfaced to a digital workstation to track system usage and examination demographics, including examination type and sensitivity number. Hard-copy films were used for diagnosis. The sensitivity number, a value inversely related to incident exposure on the imaging plate, was used to determine whether the proper techniques were used by the technologists. RESULTS: The initial use of the computed radiography system revealed a broad distribution of exposures being used; complaints regarding noisy films (e.g., underexposure) resulted in subsequent overexposure for a significant number of films. A quality-control audit indicating excessive exposure resulted in educational feedback and a tighter distribution of exposures within the optimal range as determined by our radiologists. The average technique was approximately equivalent to a 200-speed system. CONCLUSION: Computed radiography provides excellent dynamic range and rescaling capabilities for proper film optical density, and thus fewer repeat examinations. However, underexposure results in suboptimal image quality that is related to excessive quantum mottle. Overexposure requires film audits to limit unnecessary radiation exposure. In general, the optimal exposures are achieved with approximately 1.5-2 times the incident detector exposure of a 400-speed rare-earth system. The ability of computed radiography to reduce radiation exposure is unlikely when compared with a typical rare-earth screen-film combination (400 speed) in terms of adequate image quality for the diagnosis of subtle, low-contrast findings. For certain diagnostic procedures (e.g., nasogastric tube placement verification), lower exposures can be tolerated.

Iodinated nanoparticles for indirect computed tomography lymphography of the craniocervical and thoracic lymph nodes in normal dogs.

RATIONALE AND OBJECTIVES: We evaluated the imaging characteristics of an interstitially or intraperitoneally delivered iodinated particulate contrast agent for computed tomography (CT) lymphography of the craniocervical and thoracic lymph nodes. METHODS: We injected 2-4 ml of 15% wt/vol iodinated nanoparticle suspension subcutaneously, submucosally, or intraperitoneally in eight normal dogs. CT and plain radiographic images were obtained prior to contrast administration and 4 hr, 24 hr, and 7 days after injection. Correlation was made to detailed postmortem assessment. RESULTS: CT images showed enhancement of regional nodes draining injection sites. Mean attenuation of opacified nodes was 313 +/- 297 (mean +/- standard deviation), 536 +/- 453, and 492 +/- 372 Hounsfield units at 4 hr, 24 hr, and 7 days postinjection, respectively. Lymph node opacification on CT images correlated well with node location found at postmortem. CONCLUSION: Craniocervical and thoracic lymph nodes can be effectively opacified from interstitial or intraperitoneal delivery of this iodinated nanoparticulate contrast agent.

Zinner's Syndrome.

A 52-year-old male was subjected to an F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) study for the evaluation of newly diagnosed non-Hodgkin's lymphoma. An incidental non-FDG avid urinary bladder mass was detected, as well as an absent kidney. Ureterocele was suspected, but subsequently a seminal vesicle cyst was confirmed on a CT urogram.

Three-phase bone scan in osteomyelitis and other musculoskeletal disorders.

The three-phase bone scan is very sensitive and is the study of choice in the evaluation of patients with suspected osteomyelitis and normal radiographs. If the underlying bone pathology, such as a healing fracture or degenerative disease, is detected on radiographs of the bone, the indium-111-labeled autologous leukocyte scan is the most cost-effective second study. When fracture of the long bones is clinically suspected but radiographs are normal and a delay in definitive diagnosis is acceptable, it is practical and economical to take follow-up films in 10 to 14 days. In cases requiring prompt diagnosis or when follow-up radiographic films are not diagnostic, the three-phase bone scan is the most cost-effective study. The three-phase bone scan is also used in the evaluation of occupational and sports injuries, including shin splints, stress and occult fractures, enthesiopathies and reflex sympathetic dystrophy.

Approach to pulmonary metastases.

The prognosis and response to therapy of metastases to the lungs are variable and highly dependent on the origin of the primary tumor and on the extent and pattern of spread. Due to the complex pathogenesis underlying the development of pulmonary metastases, specific tumor types often display characteristic clinical and radiographic patterns. Understanding these concepts is of paramount importance when planning a diagnostic work-up for patients with possible pulmonary metastases. This review presents state of the art strategies in imaging, medical therapy, and surgery. It should provide the busy pulmonologist with the information needed to devise safe and efficient diagnostic and treatment strategies for patients with pulmonary metastases of extrathoracic origin.

Mediastinal tumors.

Mediastinal tumors are comprised of various benign and malignant neoplasms that share the same anatomic location within the thorax. The mediastinum is traditionally divided into three compartments: the anterior, middle, and posterior mediastinum. This division, based on lateral chest radiographs, helps clinicians establish appropriate differential diagnoses and plan further imaging, diagnostic, and treatment strategies. With the continued and complex advances in imaging, medical treatment, and surgery, we recommend a multidisciplinary approach to the management of mediastinal tumors. This discussion is intended to guide the pulmonary specialist through this potentially complex approach.

Unusual primary lung neoplasms.

Bronchial carcinoids and hamartomas are, respectively, the most common malignant and benign unusual primary lung neoplasms. These tumors are often asymptomatic but can cause central airway obstruction. Helical computed tomographic and radionuclide scintigraphic advances in their detection and evolution, together with newer interventional bronchoscopy techniques such as neodymium:yttrium-aluminum-garnet laser phototherapy and cryotherapy, represent important improvements in the diagnosis and management of patients with such tumors.

The costal cartilages in health and disease.

The costal margin, although imaged in many routine radiologic examinations, has been ignored in the radiology literature. Calcification of the costal cartilages follows gender-related patterns and is generally not evident radiographically until after the age of 30 years. Diffuse enlargement of the costochondral junctions may alert the astute observer to the presence of systemic diseases such as acromegaly and rickets. Focal masses have a subtle appearance on plain radiographs and may be better imaged with computed tomography (CT) or magnetic resonance imaging. Chondrosarcoma of the costal margin typically appears as an expansile mass with coarse calcifications and an associated soft-tissue mass. Radiographic and CT features of costochondritis include chondral enlargement or destruction, low-attenuation cartilage at CT, associated soft-tissue swelling, and localized peripheral cartilage calcification. There appears to be an association between heavy premature costal cartilage calcification and certain systemic conditions, such as malignancy, autoimmune disorders, chronic renal failure, and thyroid disease, particularly Graves disease.

Needle aspiration lung biopsy: reevaluation of the blood patch technique in an equine model.

PURPOSE: To reexamine the blood patch technique in a laboratory model of lung biopsy free of confounding clinical variables. MATERIALS AND METHODS: An equine model of lung biopsy was developed with an excised lobe connected to an insufflation bulb and pressure monitor. Patched and control unpatched punctures were made in the lung surface, and the pressure within the lung was raised to the maximum achievable. Whether air leakage from the puncture sites could be induced was determined and, if so, at what pressure it occurred. RESULTS: At statistical analysis with the Kaplan-Meier test and the Cox proportional hazards regression model, the difference between failure of the patched and unpatched punctures was statistically significant (P < .0001). CONCLUSION: The blood patch technique is effective in the laboratory setting and deserves reevaluation in a clinical series with updated biopsy techniques.

Imaging findings in patients with-right lower quadrant pain: alternative diagnoses to appendicitis.

Patients with right lower quadrant (RLQ) pain referred for imaging studies with a clinical diagnosis of appendicitis may have other pathologic conditions mimicking appendicitis. Appropriate diagnostic imaging may establish other specific diagnoses and thereby play a significant role in determining proper medical or surgical treatment. In this pictorial essay, we present a spectrum of imaging findings in patients whose clinical features were suggestive of appendicitis, but the diagnoses of a broad spectrum of other diseases were established with the imaging studies. The differential diagnoses of diseases mimicking appendicitis are reviewed.