Parametric images of blood flow in oncology PET studies using [15O]water.

UNLABELLED: PET was used to measure tumor blood flow, which is potentially valuable for diagnosis and assessing the effects of therapy. To help visualize regional differences in blood flow and to improve the accuracy of region-of-interest placement, a parametric imaging approach was developed and compared with the standard region-of-interest method. METHODS: Five patients with renal cell metastases in the thorax were studied using [15O]water and dynamic PET. To assess the reproducibility of the blood flow measurements, multiple water studies were performed on each patient. Model fitting was done on a pixel-by-pixel basis using several different formulations of the standard single-compartment model. RESULTS: The tumors studied spanned a wide range of blood flows, varying from 0.4 to 4.2 mL/min/g. These values were generally high compared with those of most other tissues, which meant that the tumors could be readily identified in parametric images of flow. The different model formulations produced images with different characteristics, and no model was entirely valid throughout the field of view. Although tumor blood flow measured from the parametric images was largely unbiased with respect to a standard regional method, large errors were observed with certain models in regions of low flow. The most robust model throughout the field of view had only 1 free parameter and, compared with a regional method, gave rise to a flow bias of 0.3%+/-3.1% for tumor and 16%+/-11% for low-flow soft tissue (muscle plus fat). With this model, tumor blood flow was measured with an SD of 7.6%+/-4.0%. CONCLUSION: Parametric imaging provides a convenient way of visualizing regional changes in blood flow, which may be valuable in studies of tumor blood flow.

Hibernoma: distinctive light and electron microscopic features and relationship to brown adipose tissue.

Four hibernomas and samples of developing human brown and white adipose tissue were observed. Distinctive features of hibernomas were 1) lobules of closely apposed large polygonal cells and capillaries; 2) three principal cell types (granular eosinophilic, multivacuolated, and univacuolated) varying in prominence from case to case; 3) investment of each tumor cell by basal lamina; 4) an inverse relationship between lipid droplet size and the number of mitochondria per unit of cytoplasm; 5) pleomorphic mitochondria with dense matrixes or large, round mitochondria with transverse lamellar cristae; 6) undulating plasmalemmal invaginations; 7) micropinocytotic vesicles; 8) periodic short plasmalemmal densities; and 9) a conspicuous lack of cytoplasmic membrane systems. The frequent association of micropinocytotic vesicles and undulating plasmalemmal invaginations in proximity to capillaries strongly suggests that the invaginations represent a localized cell membrane adaptation for efficient endocytosis. In human fetal brown adipose tissue, which is first recognizable in fetuses of 21 weeks' gestational age, the most characteristic cell was the polygonal multivacuolated cell. Univacuolated cells were present in brown adipose tissue of older fetuses, and in infants and adults entire lobules containing univacuolated cells coexisted with lobules of multivacuolated cells and granular eosinophilic cells. The ultrastructure of human brown adipose tissue resembled that of hibernomas and was similar to previously described features of this tissue in animals. Developing white adipose tissue differed from brown adipose tissue by its loose plexiform arrangement of capillaries and spindle-shaped cells in less circumscribed lobules and by the absence of polygonal multivacuolated cells. The authors did not identify centripetal lobular maturation in white adipose tissue, but peripheral growth "caps" were a common finding in maturing brown adipose tissue. They consider brown adipose tissue to be a special form of adipose tissue, the variable cytologic composition of which is reflected in the histologic spectrum of hibernomas.

Expression of vascular endothelial growth factor in thoracic sarcomas.

BACKGROUND: A body of data indicates that vascular endothelial growth factor (VEGF) expression by carcinomas is closely related to the prognosis of carcinomas. However, the relationship between VEGF expression and the prognosis of sarcomas is contradictory. METHODS: Tissue from 27 cases of thoracic sarcoma was analyzed immunohistochemically for VEGF expression while tumor vascularity was quantified using an antibody directed against endothelial CD34. The relationship between VEGF expression and the prognosis of patients with sarcomas was then evaluated semiquantitatively. RESULTS: The microvessel count in sarcomas with strong VEGF expression was significantly higher than that in sarcomas with absent or faint VEGF expression. The disease-free survival rates of sarcomas with strong VEGF expression were significantly lower than those of sarcomas with absent or faint VEGF expression. We found that strong VEGF expression impacted on the disease-free survival in multivariate analyses. CONCLUSIONS: VEGF expression of thoracic sarcomas is directly related to angiogenesis and tumor vascularity, and our findings suggest that strong VEGF expression is an independent prognostic factor in patients with thoracic sarcomas.

Treatment of unresectable malignant abdominal, pelvic and thoracic tumors using abdominal pelvic and thoracic stop-flow chemotherapy.

BACKGROUND: Stop-flow perfusion (SFP) has been recently used to enhance the effects of chemotherapy in patients with locally advanced tumors. PATIENTS AND METHODS: Over a 2-year period we performed abdominal, pelvic and thoracic SFP in 12 patients with unresectable or metastatic tumors, using balloon catheters inserted into the abdominal aorta and inferior vena cava. Blood flow was occluded and hypoxic extracorporeal perfusion or SFP was performed for advanced diseases. The chemotherapeutic agents were directly administered into the aorta and/or inferior vena cava for thoracic SFP. The procedure was repeated in each patient, with one-month interval between sessions. Haemofiltration was also applied in two patients with generalized abdominal disease in order to reduce systemic toxicity. RESULTS: At post-operative CT or MRI follow-up, tumor shrinkage of more than 50% was observed in six patients, while post-SFP chemotherapy surgical resection of the tumors became feasible in four cases. The relief of pain, wherever present, was dramatic in the immediate post-operative period. Overall clinical improvement was achieved in all 12 patients. Post-operative recovery was uneventful in all but two patients, who developed minor systemic toxicity. CONCLUSION: SFP appears to be a safe technique with low morbidity which improves the quality of life of cancer patients and allows satisfactory control of locally advanced tumors and metastatic carcinomatosis.

MRI of thoracic vascular lesions with emphasis on two-dimensional time-of-flight MR angiography.

MRI is a valuable method for evaluating thoracic vascular lesions by virtue of its non-invasiveness and multiplanar capability. In addition, ionizing radiation and iodinated contrast medium are not required. Electrocardiographically gated T1 weighted spin echo MRI remains the principal technique for demonstrating the anatomy and morphology of thoracic vascular diseases. Cine MRI allows dynamic evaluation of vascular flow, whereas MR angiography is particularly useful in the two-dimensional (2D) or three-dimensional (3D) display of vascular anatomy. This pictorial review illustrates the use of 2D time-of-flight MR angiography in the assessment of various thoracic vascular conditions including aortic arch and great vessel anomalies, heterotaxic syndromes, aortic dissection, aortic or arch vessel aneurysms, pulmonary embolism, pulmonary sequestration, axillofemoral bypass and tumour/vessel relationships.

Distal arteriovenous fistula to maintain patency of the venous drainage of a latissimus dorsi flap following subclavian vein repair.

Successful reconstructive surgery with muscle flaps depends on adequate arterial supply and undisturbed venous drainage. Combining such surgery with reconstructive vascular surgery of a large-caliber vein that is responsible for the venous drainage of the flap poses an additional challenge--the repaired vein's susceptibility to thrombosis. Every attempt must be made to prevent venous outflow obstruction following muscle flap surgery. Data from the vascular surgery literature demonstrate a low success rate for subclavian vein repair. The success rate with venous reconstructive surgery has been greater when a distal arteriovenous fistula accompanied the repair. The present case described the use of a temporary distal cephalic-brachial arteriovenous fistula to maintain the patency of the venous drainage of a pedicled latissimus dorsi muscle flap, following subclavian vein repair, for one-stage coverage of a large chest wall defect.

Giant tumors of the chest: preoperative embolization and resection.

Giant tumors of the chest are rare. These tumors comprise a spectrum of disease from benign lesions to highly aggressive malignant tumors with cells of origin in the pleura, pulmonary parenchyma, blood vessels, thymus, and connective tissues. We report four cases of giant tumors of the thorax treated with preoperative arterial embolization followed by complete surgical resection. Their diagnostic and treatment courses, imaging, and pathology are described.

Total excision of a giant angiolipoma of chest wall with A-V malformation and with the use of an autotransfusion system.

An 18 year old girl suffering from a giant angiolipoma of back and chest wall with A-V malformation underwent total excision of the tumor in 4 stages. The first two stages included surgical ligation of the arterial blood supply to the tumor. In the third and fourth stages the tumor was resected with the use of an autotransfusion system. The last stage was complicated with massive bleeding and disseminated intravascular clotting. Control of bleeding was achieved by the use of autotransfusion system, right thoracotomy and massive transfusion of blood and its components. After long convalescence period associated with renal and respiratory failure the patient recovered completely without sequellae. This case demonstrates the complexity associated with the treatment of these rare tumors.

Refractory bleeding from a chest wall sarcoma: a rare indication for palliative resection.

We report a case of a 57-year-old male who presented with an inoperable chest wall sarcoma due to numerous pulmonary metastases and was treated with chemotherapy and radiation therapy. The patient subsequently developed refractory bleeding from the chest wall tumor requiring palliative chest wall resection and reconstruction. The patient made an uneventful recovery however died from metastatic disease 8 months later. This case represents a very rare indication for palliative chest wall resection.

Oklahoma prosthesis: resection of tumor of clavicle and chest wall reconstructed with a custom composite graft.

Tumors involving the clavicle by primary or metastatic growth may require clavicular resection often with rib resection. The resulting cosmetic and functional impairment of clavicular resection may be significant with a sloped appearing shoulder girdle and chronically impaired movement of the upper extremity. We report a 48-year-old woman presenting with a bulky metastatic renal cell mass of her left clavicle extending to the chest wall. We report en-bloc clavilculectomy and chest wall resection with a novel method of reconstruction using a single methyl methacrylate and prolene composite prosthesis in a configuration resembling the state of Oklahoma.

[MR angiography in intrathoracic masses: evaluation of the superior vena cava, its major branches and their relation to the mass].

MR angiography (MRA) of the thorax was evaluated in six healthy volunteers and 48 patients with an intrathoracic mass potentially infiltrating to the superior vena cava and/or its major branches. It was also compared with CT, spin echo MRI and X-ray venography. Three methods were used for MRA: sequential 2D-TOF MRA with presaturation band over the heart, 3D-MRA with bolus administration of Gd-DTPA in a single breath-hold and sequential 2D-TOF MRA with administration of Gd-DTPA. The major vessels themselves and their relation to the mass were clearly visualized on MRA in all volunteers and patients. Since original MRA demonstrated these vessels more clearly than projection MRA in our series, we considered that interpretation of MRA should be based mainly on original MRA. MRA generally could visualize the vessels as well as the other imaging modalities, and was sometimes superior to them. In conclusion, MRA is a non-invasive and effective method for the evaluation of major vessels and their relation to the mass in patients with an intrathoracic mass.

[MR angiography of thoracic blood vessels]. / MR-Angiographie der Thorakalgefässe.

Through the introduction of newly invented high-performance gradient systems to MRI, which enable for echoplanar imaging (EPI), also magnetic resonance angiography (MRA) has gained an entirely new field of applications and techniques. Ultrafast imaging techniques in MRA allow the investigation of larger vascular areas within a single breath-hold-period. Artifacts like motion induced signal misregistrations, dephasing or saturation of the vascular signal are minimized by extremely short echo times. The technique thus requires the intravenous application of a contrast media bolus, usually a gadolinium compound, which is in standard clinical use. Coordination of the bolus injection and the timing of the data acquisition is crucial for optimal results. The first pass evaluation of the contrast media resembles CTA to a certain extend. Due to the fast measurement and the high contrast in contrast-enhanced MRA (CE-MRA) new applications and indications are developed like MRA of the pulmonary vessels. The paper offers considerations and trials for optimization of thoracical CE-MRA. Besides parameter constellation also bolus-optimization is described with respect to the dedicated anatomical premises. Investigations on volunteers and on patients build a basis for suggestions of optimized CE-MRA procedures. To date, a final estimation of the clinical value of the new technique cannot be given since ongoing improvements change the optimal protocol frequently and the potential of further developments is high.

The angiographic features of extraabdominal desmoid tumors.

Extraabdominal desmoid tumors are nonencapsulated locally invasive neoplasms of fibrous tissue. The angiographic features include arterial stretching, neovascularity, and tumor staining (4 of 6 cases in this series). Although benign, these tumors are difficult to cure because they tend to recur locally.

Vascular spindle cell lipoma.

Spindle cell lipoma is a neoplasm of adipose tissue that primarily affects posterior necks and shoulders of men in their fifth to seventh decades. It consists of a mixture of adipose tissue and spindle-shaped cells that could be misinterpreted as sarcoma. A clinical and pathological study of two patients, both men, with vascular variants of spindle cell lipoma is presented. These tumors were unusual clinically, in that one caused pain on motion and the other was painful to palpation. On microscopic examination, their vascularity was augmented over previously described examples of spindle cell lipoma.

Use of Doppler sonography to differentiate AIDS-related intrathoracic lymphoma from tuberculosis.

We present a case of AIDS-related intrathoracic lymphoma in which the pulmonary lesions were evaluated with Doppler sonography. The presence of internal vascularity within such lesions may help to differentiate this entity from tuberculosis.

Complications of embolization treatment for problem cavernous hemangiomas.

Radiologists trained in selective angiography can now deliver sclerosing or occluding materials to the arterial supply of vascular tumors. Such skills require special training and there are limitations to the use of these materials. Specific obliteration can be carried out if this technique is quality controlled. Materials being used for embolization are continually being studied and are changing as new materials are developed. Radiologists can assist surgeons in managing some of these very difficult problems. A large series of patients with various vascular lesions treated at the Oregon Health Sciences University was reviewed. The complications of embolization used for cavernous hemangiomas have tempered our enthusiasm for it as an adjunct form of therapy. We do feel that this method of treatment remains useful in selected cases. The occlusion achieved caused a decrease in both symptoms and size of lesions treated. The decrease in size excluded the need for surgery in 3 cases, aided resection in 1, but caused significant complicating slough in 1. Five cases are presented to demonstrate problems of tissue necrosis encountered.