Image-guided management of complicated pleural fluid collections.

Percutaneous image-guided catheter drainage with adjunctive ICFT has become the mainstay in the treatment of complicated pleural fluid collections. There are six basic principles of image-guided drainage and ICFT that must be understood to maximize the efficacy and safety of the procedure. 1. There must be a basic understanding of why traditional nonguided thoracostomy drainage fails in a significant percentage of patients. Tube malposition relative to fluid loculations, fluid debris and viscosity, and the presence of a stage 3 pleural peel are the primary reasons for failure. Image-guided placement of drains addresses the issue of tube malposition and ICFT greatly facilitates drainage of fibrinous fluid. 2. Proper use of cross-sectional imaging is one of the keys to ultimate success. CT and ultrasound allow very accurate assessment of the underlying pathologic process and are crucial in planning the drainage procedure, guiding the actual placement of drains, and following the course and outcome of treatment. The added costs of cross-sectional imaging are more than compensated by the increase in success of the drainage procedure. 3. Aggressive catheter management is the single most important factor in success. Multiple loculations require multiple catheters for adequate drainage. Pleural adhesions may form quickly as drainage progresses leading to the formation of undrained loculations. Frequent cross-sectional imaging is needed to detect undrained loculations so that additional drainage catheters may be placed if needed. It is crucial that the drainage catheter always be properly positioned in relation to fluid loculations. 4. Intracavitary fibrinolytic therapy is a very powerful adjunctive therapy to aid in complete evacuation of fluid collections that contain fibrin nets and debris. It can also partially débride the pleural surfaces of fibrinous debris and facilitate complete re-expansion of the underlying lung. Intracavitary fibrinolytic therapy should not be used in an attempt to salvage success by a malpositioned chest tube. 5. The ultimate success of closed drainage for complicated pleural fluid collections is closely related to the age of the effusion at the time of drainage. A very high rate of clinical success may be expected when these techniques are used in the treatment of stage 2 fibrinopurulent effusions. If drainage is delayed until the third stage (fibrous pleural peel formation) then closed drainage likely will fail and a formal thoracotomy and decortication will be necessary. Experience in the literature suggests that effusions up to 4 to 6 weeks in duration may be drained successfully but those older than 6 weeks likely will have an associated pleural peel. Effective pleural drainage must be instituted early in the course of the disease process. 6. There may be significant residual pleural and parenchymal inflammatory changes after complete drainage of a stage 2 effusion. If the fluid in the pleural space has been adequately drained and the visceral and parietal pleural surfaces apposed, then the residual inflammatory pleural thickening and associated lung consolidation resolve over 2 to 4 months and pulmonary function returns to baseline. Imaging studies immediately after complete pleural drainage are not normal. These residual abnormalities should not be interpreted as evidence that open surgical drainage should have been performed. Effective closed drainage carries lower morbidity, mortality, and cost than does open surgical drainage. For radiologists and clinicians alike it does not suffice simply to place one or more thoracostomy tubes, round daily, and hope that the occasional use of fibrinolytic agents does the rest. Without a more aggressive approach to catheter position and management the efficacy is no greater than that historically seen with nonguided closed drainage and surgeons will continue to plead for earlier effective open drainage.

Image-guided drainage techniques.

The basic principles of empyema management center on the initiation of antibiotics and effective pleural space drainage. For patients with empyemas in the exudative or fibrinopurulent stage, image-guided chest tubes have markedly improved patient care. These catheters can be placed into ideal positions within the chest by the use of various imaging techniques to promote effective drainage. Because of a minimal need for tissue dissection, patients tolerate image-guided catheters well with only local anesthetics. Multiple techniques exist to augment tube drainage if necessary. Available approaches include tube exchange with placement of a larger-caliber catheter, tube manipulation, and fibrinolytic therapy. However, success of image-guided catheters depends on proper patient selection, the skills of the operator, and the ability to monitor daily chest tube function to ensure adequacy of drainage. Open surgical procedures can be avoided in most treated patients.

Rhenium-188(Sn)HEDP for treatment of osseous metastases.

UNLABELLED: Rhenium-188 (tin) hydroxyethylidine diphosphonate [188Re(Sn)HEDP] is a new radiopharmaceutical that localizes in skeletal metastases and emits beta particles that may be therapeutically beneficial. METHODS: It was evaluated by in vitro and in vivo testing in the laboratory, in animals and in humans using 188Re from a variety of sources. It may be produced by a desk-top method developed previously for 186Re(Sn)HEDP using 188Re produced through neutron irradiation of either enriched 187Re or naturally occurring rhenium targets or the use of a 188W/188Re generator. RESULTS: So long as the mass of rhenium in the 188Re-perrhenate to be processed into 188Re(Sn)HEDP is at least 100 microg, satisfactory radiochemical yields and purity may be obtained by all methods. The 188Re(Sn)HEDP has biodistribution and radiation dosimetry characteristics that are similar to those noted previously for 186Re(Sn)HEDP and appears to result in similar benefits and toxicities in patients with skeletal metastases. External radiation exposure monitoring indicates that, only 4 hr after a therapeutic administration of 1110 MBq (30 mCi) of 188Re(Sn)HEDP, average exposure rates at 1 meter from the patient would be only 0.5 mR/hr. CONCLUSION: Same-day, on-demand, outpatient therapy of disseminated skeletal metastases appears to be feasible with 188Re(Sn)HEDP.

Primary hepatic pheochromocytoma?

We report a case of a single intrahepatic pheochromocytoma in the absence of an adrenal lesion and no evidence of metastatic disease. The patient had strong clinical and biochemical evidence of a pheochromocytoma. A CT scan was abnormal but nondiagnostic for pheochromocytoma. An 123I-metaiodobenzyl guanidine (MIBG) scan was falsely negative, but an MRI scan showed a definitive hepatic abnormality. After confirmation of endocrine activity by venous sampling, the tumor was surgically removed. The patient's symptoms have resolved and her plasma catecholamine levels as well as her 24-h urine catecholamine excretion have normalized. The case shows an unusual location of an isolated pheochromocytoma and provides an example of a false negative I-123 MIBG scan.

Treatment of complicated pleural fluid collections with image-guided drainage and intracavitary urokinase.

STUDY OBJECTIVE: We report the results of image-guided catheter drainage with adjunctive enzymatic pleural debridement in the treatment of empyemas and other complicated pleural fluid collections. DESIGN: Retrospective review. PATIENTS: One hundred eighteen patients with complicated pleural fluid collections were treated with image-guided drainage. There were 79 empyemas, 27 sterile loculated parapneumonic effusions, 10 sterile hemothoraces, and 2 sterile postoperative exudative effusions. Forty-one patients had failed prior large-bore thoracostomy drainage. The estimated age of the effusions at the time of image-guided drainage ranged from 1 to 175 days with a mean estimated age of 13 days. INTERVENTIONS: Patients were treated with image-guided placement of one or more 12F to 16F chest drains. Adjunctive urokinase instillation was used in 98 cases. Urokinase (100,000 to 250,000 U/mL) was instilled in 20 to 240-mL aliquots and reaspirated in 1 to 4 h. One to four instillations were performed per day until drainage was complete. MEASUREMENTS AND RESULTS: Drainage was successful in 111 cases (94%). Two patients died of sepsis with incomplete drainage. Five patients underwent decortication (three recovered and two died postoperatively). Fifty-three patients (45%) required placement of more than one drain. The mean duration of drainage was 6.3 days. Patients treated with pleurolysis required a mean of five instillations of urokinase. The mean total dose of urokinase used per case was 466,000 U. There were no complications. CONCLUSION: Image-guided drainage with adjunctive pleural urokinase therapy is a safe and effective method of closed thoracostomy drainage of complicated pleural fluid collections and can obviate surgery in most cases.

MR imaging of soft-tissue masses: diagnostic efficacy and value of distinguishing between benign and malignant lesions.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of MR imaging in predicting the pathologic diagnosis of soft-tissue masses, both neoplastic and nonneoplastic, and in distinguishing benign from malignant lesions. MATERIALS AND METHODS: The imaging features of 225 soft-tissue tumors (179 benign, 46 malignant) in 222 patients were analyzed. Univariate analysis of multiple individual imaging features was done, along with stepwise logistic regression analysis of combinations of imaging features, to determine how useful these are for predicting malignancy or benignity. A subjective (group consensus) analysis of each case was done prospectively, and each tumor was placed into one of three diagnostic categories: (1) benign, diagnostic of a specific entity; (2) nonspecific, most likely benign; or (3) nonspecific, most likely malignant. Results were compared with the final diagnosis established by pathologic examination (n = 184) or imaging/clinical data (n = 41). RESULTS: By quantitative analysis, no single imaging feature or combination of features could reliably be used to distinguish benign from malignant lesions. For the subjective analysis, a correct and specific benign diagnosis could be made on the basis of MR imaging findings in 100 (44%) of the 225 tumors. For the entire cohort, the sensitivity was 78%, the specificity was 89%, the positive predictive value was 65%, and the negative predictive value was 94% for a malignant diagnosis. When the diagnostic benign tumors were excluded, the specificity and negative predictive value decreased to 76% and 86%, respectively, whereas the sensitivity and positive predictive value remained the same. CONCLUSION: Many benign soft-tissue masses can be correctly and confidently diagnosed with MR imaging. The prevalence of benign lesions among soft-tissue masses accounts for the relatively high specificity and negative predictive value that can be achieved with MR imaging for tissue characterization. However, the accuracy of MR imaging declines when these characteristic benign tumors are excluded from analysis. A significant percentage of malignant lesions may appear deceptively "benign" with the currently used criteria. For lesions whose imaging appearance is nonspecific, MR imaging is not reliable for distinguishing benign from malignant tumors, and these lesions warrant biopsy in most cases.

A Monte Carlo simulation model for radiation dose to metastatic skeletal tumor from rhenium-186(Sn)-HEDP.

UNLABELLED: A Monte Carlo model has been developed for simulation of dose delivery to skeletal metastases by the bone surface-seeking radiopharmaceutical 186Re (Sn)-HEDP. METHODS: The model simulates: (1) the heterogeneous small scale geometry of the soft tissue/bone-spicule structure in the lesions as determined by histomorphometric measurements of histologic specimens, (2) the small scale spatial distribution of the radiopharmaceutical on the lesion bone spicule surface as determined by autoradiography, and (3) the 186Re beta and conversion electron decay spectrum and the associated charged particle transport within the modeled geometries. The results are compared with the commonly employed uniform lesion model, which assumes: (1) homogeneous lesion morphology, (2) uniform distribution of radioactivity within the lesion, and (3) complete energy deposition by charged particles within the lesion due to decay of this activity. Gamma and x-ray photons from the 186Re spectrum were assumed to escape from the lesion volume in both models. RESULTS: Results show a significant dependence on the bone volume fraction and hence on the histology of the lesion (lytic, blastic or mixed). The uniform lesion model calculations underestimate the radiation dose to blastic lesions by as much as a factor of 1.8. However, for lytic lesions with low bone volume fractions, both models provide similar dose values. CONCLUSIONS: These new model calculations provide a mechanism for optimizing treatment planning and dose response evaluations of therapeutic bone-seeking radiopharmaceuticals.

Rupture of the distal biceps tendon: evaluation with MR imaging.

PURPOSE: To assess the usefulness of magnetic resonance (MR) imaging in the diagnosis of distal biceps tendon ruptures. MATERIALS AND METHODS: MR images of the elbow in 20 patients with suspected distal biceps injury were retrospectively reviewed along with those of eight asymptomatic volunteers. Surgical confirmation was obtained in nine cases. RESULTS: MR imaging helped diagnose 10 complete ruptures with depiction of the absence of the tendon distally (n = 10), a fluid-filled tendon sheath (n = 9), an antecubital fossa mass (n = 3), muscle edema (n = 3), and atrophy (n = 2). Six partial tears were depicted with high signal intensity within the tendon (n = 6), fluid in the biceps tendon sheath (n = 6), and thinning (n = 3) or thickening (n = 3) of the distal tendon. Of the remaining patients, one each had tendinosis, tenosynovitis, a biceps hematoma, and a brachialis contusion. CONCLUSION: MR imaging helped confirm distal biceps tendon ruptures because it distinguished complete from partial ruptures and other entities that may mimic ruptures.

Fibrosing mediastinitis causing nonvisualization of one lung on pulmonary scintigraphy.

An interesting case of fibrosing mediastinitis, which is a rare cause of total nonvisualization of one lung on pulmonary scintigraphy, is presented. Scintigraphy with Tc-99m MAA showed a severe deficit of perfusion in the right lung, with normal perfusion of the left lung. Ventilation images were normal. CT and MRI each demonstrated the mediastinal nodal enlargement and MRI demonstrated the "flow void" signal phenomenon in the right pulmonary artery indicating its patency. Confirmation of actual patency without pulmonary artery emboli and with poor venous opacification was documented with angiography. Multiple complementary imaging modalities were helpful in correctly diagnosing fibrosing mediastinitis from an extensive list of differential possibilities for unilateral non-visualization of the lung on perfusion scanning.

Overview of diagnostic imaging in sepsis.

This article discusses available imaging modalities with an emphasis on patient preparation and techniques to optimize image quality. Appropriate imaging of localized sepsis is then discussed, with a description of imaging features of common causes of sepsis. Finally, an imaging approach is discussed in the septic patient without localizing features.

Percutaneous abscess drainage in the management of sepsis.

Image-guided percutaneous drainage has become the procedure of choice for a wide variety of abscesses and other fluid collections, and is an invaluable therapeutic alternative for the management of septic patients. Growing experience, along with technical advances, has significantly broadened the potential applications of percutaneous abscess drainage. Important considerations include the use of modern imaging techniques to identify and characterize sources of sepsis, appropriate patient selection and definition of therapeutic goals, and dedicated involvement by the interventional radiology team. The current methods and applications of percutaneous abscess drainage are reviewed, both in general, and in terms of specific anatomic locations and disease processes.

Coaxial percutaneous biopsy technique with automated biopsy devices: value in improving accuracy and negative predictive value.

Three hundred percutaneous biopsies were performed in 267 consecutive patients by means of a coaxial technique with use of 18- and 20-gauge automated cutting biopsy devices and 22-gauge aspiration needles. Thoracic, hepatic, renal, pancreatic, adrenal, splenic, retroperitoneal, and musculoskeletal soft-tissue masses were sampled. For malignant masses (229 cases), the sensitivity was 79% for cytologic analysis, 88% for histologic analysis, and 92% for both combined. In benign disease (71 cases), a correct specific diagnosis was made with cytologic analysis in 38%, with histologic analysis in 97%, and with both combined in 97%. The negative predictive value was 60% for cytologic analysis, 72% for histologic analysis, and 80% for both combined. When only cancer-negative results in which a specific benign diagnosis was made were considered, the negative predictive value was 100% for cytologic analysis, 97% for histologic analysis, and 97% for both combined. The positive predictive value was 100% for both cytologic and histologic analysis. Bleeding complications occurred in 3% of biopsies, including in one patient who died.

Rhenium-186 hydroxyethylidene diphosphonate for the treatment of painful osseous metastases.

Rhenium-186 (tin)hydroxyethylidene diphosphonate (HEDP) is a new radiopharmaceutical that localizes in skeletal metastases in patients with advanced cancer. A single intravenous administration of approximately 34 mCi (1,258 MBq) resulted in significant improvement in pain in 33 of 43 evaluable patients (77%) following the initial injection, and in 7 of 14 evaluable patients (50%) following a second treatment. Patients responding to treatment experienced an average decrease in pain of about 60%, with one in five treatments resulting in a complete resolution of pain. The only adverse clinical reaction was the occurrence after about 10% of the administered doses of a mild, transient increase in pain within a few days following injection. Statistically significant but clinically unimportant decreases in total white blood cell counts and total platelet counts were observed within the first 8 weeks following the injection; no other toxicity was apparent. Rhenium-186(Sn)HEDP is a useful new compound for the palliation of painful skeletal metastases.

Rhenium-186(Sn)HEDP for treatment of painful osseous metastases: results of a double-blind crossover comparison with placebo.

Rhenium-186 (tin) hydroxyethylidene diphosphonate (HEDP) is a new radiopharmaceutical that simultaneously localizes in multiple skeletal metastases in patients with advanced cancer. A single intravenous administration of 30-35 mCi (1110-1295 MBq) is associated with a prompt, significant relief of osseous pain in about 80% of such patients. The efficacy of this new compound was evaluated further by utilizing a double-blind crossover comparison with 99mTc-methylene diphosphonate (MDP) as a radioactive placebo. The new rhenium compound resulted in a significantly (p less than 0.05) greater decrease in pain than did treatment with the radioactive placebo. Rhenium-186(Sn)HEDP appears to be a useful new compound for the palliation of painful skeletal metastases.

Diagnosis of segmental necrosis in a pancreas transplant by thallium-201 perfusion scintigraphy.

Thallium-201 was used to image a patient with a pancreatic transplant. Incomplete visualization of the graft on the 201Tl scan, compared to CT, led to the diagnosis of segmental necrosis of the tail of the graft. Due to the low background and favorable target-to-non-target ratio, 201Tl pancreas scintigraphy may be useful in the follow-up of pancreatic transplants.