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Biomedical subjects

J B Kruskal

Publications and source records attributed to J B Kruskal.

At least 19 recordsLinked to original sources
PubMed2001

Multiphase contrast-enhanced helical CT of liver metastases from renal cell carcinoma.

The aim of this study was to evaluate whether in patients with metastatic renal cell carcinoma (RCC) multiphase liver studies would improve detection of metastatic liver disease. Forty-six consecutive patients with known metastatic RCC underwent standardized non-contrast and triphasic contrast enhanced hepatic CT examinations as part of their routine imaging studies. Once a liver abnormality was detected, it was characterized as metastatic by a panel of three radiologists who followed pre-set criteria. These criteria included change in size, biopsy results and lack of benign features. Presence and conspicuity of liver metastases were graded using a five-point scale by consensus of a panel of three radiologists. The highest number of lesions evaluated per patient was limited to ten. Seventy-two liver metastases were detected in 16 patients. Of these, 54 were seen on unenhanced scans; 47 in the hepatic arterial (HA) phase, at 25 s; 65 in the portal-venous (PV) phase, at 60 s; and 49 in delayed images, at 90 s. Scanning only during the PV phase would have missed seven lesions (10%), six of which were seen on unenhanced images and six were seen in HA phase. All patients with metastatic liver disease would have been identified by combination of unenhanced and PV phase or by HA and PV phase scanning. Forty-two lesions were graded more conspicuous on the PV phase, whereas 18 (25%) were more conspicuous on the HA phase. The combination of unenhanced, HA and PV scanning should be considered in the initial evaluation of patients with metastatic RCC for improved lesion detection and characterization. Subsequently, the combination of unenhanced and PV phase imaging is preferred.

Adult↗
PubMed2001

Intraoperative ultrasound.

Intraoperative ultrasound is an exciting arena for real-time depiction and evaluation of relevant anatomy and pathology. The information provided by this technique often is pivotal to the surgeon, and not infrequently impacts the nature and extent of the surgical procedure. As more radiologists develop an interest and become facile with IOUS, and as more surgeons appreciate the benefits of this modality, the numbers and applications for this technique will continue to expand. This, coupled with continued commercial and technical improvements, and increasing demand for minimally invasive surgery, ensures that the future of IOUS will be a bright one.

Equipment Design↗
PubMed2001

Dynamic intrahepatic flow and cellular alterations during radiofrequency ablation of liver tissue in mice.

PURPOSE: The purpose of this study was to identify microvascular and other associated changes that occur in the liver during focal heating with monopolar radiofrequency (RF). MATERIALS AND METHODS: Intravital video microscopy was performed on exteriorized transilluminated livers of 15 live mice during RF-induced heating of liver parenchyma. Microvascular flow parameters, flow reversibility, microbubble formation, phagocytic activity, and endothelial permeability were recorded throughout a range of tip temperatures (40 degrees C-95 degrees C). RESULTS: During RF application, five discrete zones extended outward from the electrode surface: (i) tissue coagulation, (ii) cellular edema/necrosis, (iii) sinusoidal stasis, (iv) parenchymal shunting, and (v) normal liver tissue. Reversal of stasis in sinusoids and small (<25 microm) vessels occurred at tip temperatures below 50 degrees C. This zone of stasis corresponded to the hyperemic zone on histologic analysis. Although alterations in permeability and phagocytic activity were first identified at 43 degrees C, tip temperatures higher than 55 degrees C always produced local endothelial leakiness to carbon microparticles at the periphery and always inhibited phagocytic activity. At tip temperatures higher than 95 degrees C, microbubble formation occurred with bubbles ultimately tracking through necrotic tissue into patent sinusoids. Larger peripheral vessels (>30 microm) limited extension of coagulation. CONCLUSION: Although coagulation occurs at tip temperatures higher than 50 degrees C, RF heating induced reversible microvascular stasis at temperatures lower than 50 degrees C. Increased sinusoidal endothelial permeability occurs at near-coagulative temperatures. Therefore, targeted endovascular microparticle delivery through this leaky endothelium may provide an additional and complimentary adjunct for RF ablation therapy.

Animals↗
PubMed2001

Imaging for right lobe living donor liver transplantation.

The authors describe their experience using multidetector, multiphase computed tomography (CT) for the preoperative evaluation of donors undergoing adult right lobe liver transplantation. The marked improvement in image resolution has been extremely valuable in delineating small hepatic arterial structures, including accessory and replaced vessels. Assessment of liver parenchyma is valuable in determining the presence of steatosis or other unexpected abnormalities. Measurement of total liver volume is highly accurate and reproducible. Virtual hepatectomy can be performed in an avascular plane between the right and left lobes, to the right of the middle hepatic vein. Knowledge of the resultant right and left lobe volumes is critical in patient selection. Multidetector, multiphase CT, as a single imaging modality, provides a minimally invasive comprehensive pre-operative evaluation that can be expected to have a major impact on patient selection and surgical planning.

Hepatectomy↗
PubMed2001

Peroxide-enhanced anal endosonography: technique, image interpretation, and clinical applications.

Because current techniques for examination and imaging of perianal fistulas tend to underestimate the extent, location, and course of perianal fistulas--information essential for decisions about surgical management--the use of hydrogen peroxide was investigated as an image-enhancing contrast agent for confirmation of the presence of and improvement in the depiction of fistulas during endoanal ultrasonography (US). After conventional endoanal US was performed with a side-fire 7.5- or 10.0-MHz rotating endoprobe, external perianal openings were cannulated and approximately 1 mL of peroxide was administered. After reinsertion of the endoprobe, the entire course of the echogenic fistula, including its relation to the internal and external sphincters and the levator ani muscle, was depicted in real time in three dimensions. This depiction of fistulas permits accurate classification, which facilitates surgical planning. In experience with more than 60 patients, peroxide-enhanced endoanal US was found to be a useful technique for documentation of the presence, number, and internal course of perianal fistulas and for characterization of abnormalities seen at endosonography performed without use of contrast enhancement. In addition, the technique permitted surgeons to stratify patients into treatment groups and has been especially useful for planning surgical treatments.

Anal Canal↗
PubMed2001

Radio-frequency thermal ablation with NaCl solution injection: effect of electrical conductivity on tissue heating and coagulation-phantom and porcine liver study.

PURPOSE: To characterize the effects of NaCl concentration on tissue electrical conductivity, radio-frequency (RF) deposition, and heating in phantoms and optimize adjunctive NaCl solution injection for RF ablation in an in vivo model. MATERIALS AND METHODS: RF was applied for 12-15 minutes with internally cooled electrodes. For phantom experiments (n = 51), the NaCl concentration in standardized 5% agar was varied (0%-25.0%). A nonlinear simplex optimization strategy was then used in normal porcine liver (n = 44) to determine optimal pre-RF NaCl solution injection parameters (concentration, 0%-38.5%; volume, 0-25 mL). NaCl concentration and tissue conductivity were correlated with RF energy deposition, tissue heating, and induced coagulation. RESULTS: NaCl concentration had significant but nonlinear effects on electrical conductivity, RF deposition, and heating of agar phantoms (P<.01). Progressively greater heating was observed to 5.0% NaCl, with reduced temperatures at higher concentrations. For in vivo liver, NaCl solution volume and concentration significantly influenced both tissue heating and coagulation (P<.001). Maximum heating 20 mm from the electrode (102.9 degrees C +/- 4.3 [SD]) and coagulation (7.1 cm +/- 1.1) occurred with injection of 6 mL of 38.5% (saturated) NaCl solution. CONCLUSION: Injection of NaCl solution before RF ablation can increase energy deposition, tissue heating, and induced coagulation, which will likely benefit clinical RF ablation. In normal well-perfused liver, maximum coagulation (7.0 cm) occurs with injection of small volumes of saturated NaCl solution.

Animals↗
PubMed2001

Percutaneous tumor ablation: increased necrosis with combined radio-frequency ablation and intratumoral doxorubicin injection in a rat breast tumor model.

PURPOSE: To determine whether a combination of intratumoral doxorubicin injection and radio-frequency (RF) ablation increases tumor destruction compared with RF ablation alone in an animal tumor model. MATERIALS AND METHODS: R3230 mammary adenocarcinoma 1.2-1.5-cm- diameter nodules (n = 110) were implanted subcutaneously in 84 female Fischer rats. For initial experiments (n = 46), tumors were treated with (a) conventional, monopolar RF (250 mA +/- 25 [SD] at 70 degrees C +/- 1 for 5 minutes) ablation alone; (b) direct intratumoral doxorubicin injection (volume, 250 microL; total dose, 0.5 mg) alone; (c) combined therapy (doxorubicin injection immediately followed by RF ablation); (d) RF ablation and injection of 250 microL of distilled water; or (e) no treatment. In subsequent experiments, amount of doxorubicin (0.02-2.50 mg; n = 40 additional tumors) and timing of doxorubicin administration (2 days before to 2 days after RF ablation; n = 24 more tumors) were varied. Pathologic examination, including staining for mitochondrial enzyme activity and perfusion, was performed, and the resultant tumor destruction from each treatment was evaluated. RESULTS: Coagulation diameter was 6.7 mm +/- 0.6 for tumors treated with RF ablation alone and 6.9 mm +/- 0.7 for those treated with RF ablation and water (P =.52), while intratumoral doxorubicin injection alone produced only 2.0-3.0 mm of coagulation (P <.001). Increased coagulation was observed only with combined doxorubicin injection and RF therapy (P <.001). Coagulation was dependent on concentration and timing of doxorubicin administration, with greatest coagulation (11.5 mm +/- 1.1) observed for doxorubicin administered within 30 minutes of RF ablation. CONCLUSION: Adjuvant intratumoral doxorubicin injection increases coagulation in solid tumors compared with RF ablation alone. Increased tumor destruction is also seen when doxorubicin is administered after RF ablation, which suggests that RF ablation may sensitize tumors to chemotherapy. Such combination therapies may, therefore, offer improved methods for ablating solid tumors.

Adenocarcinoma↗
PubMed2001

Impact of multidetector CT on donor selection and surgical planning before living adult right lobe liver transplantation.

OBJECTIVE: This study was performed to document the impact of multidetector multiphase CT in facilitating patient selection and surgical planning in potential donors being evaluated for living adult right lobe liver transplantation. SUBJECTS AND METHODS: Forty consecutive potential donors were included in the study. There were 26 men and 14 women, (age range, 18-57 years; mean, 37 years) We performed CT using a multidetector scanner, after IV injection of 180 mL of contrast material at 5 mL/sec. Arterial phase images were acquired at 18 sec (collimation, 1.25 mm; table speed, 7.5) and portal phase images, at 60 sec (collimation, 2.5 mm; table speed, 15). Postprocessing was performed on a commercially available workstation. CT data included dual-energy assessment of liver parenchyma for fatty infiltration; depiction of arterial, portal venous, and hepatic venous anatomy and identification of important vascular variants; and determination of total and lobar liver volume. RESULTS: Of the 40 potential liver donors evaluated, 15 patients (37.5%) were excluded on the basis of CT findings, with most exclusions a result of portal vein anomalies (n = 8). Fatty infiltration resulted in four exclusions (10%), and small liver volume resulted in three exclusions (7.5%). CONCLUSION: Multidetector multiphase CT provided comprehensive parenchymal, vascular, and volumetric preoperative evaluation of potential donors undergoing living adult right lobe liver transplantation. This information had a major impact on patient selection because it was used to stratify patients. It allowed the surgeons to plan their surgical approach, and this planning may reduce postoperative complications.

Adolescent↗
PubMed2001

Accuracy of volumetric measurements after virtual right hepatectomy in potential donors undergoing living adult liver transplantation.

OBJECTIVE: The purpose of this study was to evaluate accuracy for determining the total and lobar liver volumes using a multidetector CT scanner in potential donors undergoing living adult right lobe liver transplantation. SUBJECTS AND METHODS: Fifty-two adult donors underwent CT using a multidetector scanner after IV injection of 180 mL of contrast material. For volumetric determination, portal venous phase images were acquired at 60 sec. Hand-tracing was used to isolate the entire liver, and a curved hepatectomy plane was then identified in a manner simulating the surgical incision. Two observers performed hand-tracing of the entire liver to calculate total liver volume, and of the right lobe to calculate expected graft volume. RESULTS: The mean volume of the entire liver, right lobe, and left lobe was 1807 mL, 990 mL, and 817 mL, respectively, for observer 1, and 1788 mL, 1007 mL, and 781 mL, respectively, for observer 2. There was significant agreement between the two observers in determining total and lobar liver volumes (r = 0.996, 0.977, and 0.965 for total, right lobe, and left lobe volumes, respectively; p< 0.0001). There was no statistically significant difference between the two observers in measuring total or lobar liver volumes (p< 0.0001). There was significant agreement between right lobe volume measured by each observer and graft weight obtained in 14 donors at surgery (r = 0.898 and 0.879, for observers 1 and 2, respectively; p <0.001). CONCLUSION: Total and lobar volume determinations after virtual right hemihepatectomy provides accurate and reproducible information that is critical in selecting potential living liver donors.

Adolescent↗
PubMed2001

State-of-the-art ultrasonography is as accurate as helical computed tomography and computed tomographic angiography for detecting unresectable periampullary cancer.

OBJECTIVE: To compare the ability of state-of-the-art ultrasonography with that of helical computed tomography and computed tomographic angiography in detecting unresectable periampullary cancer. In most patients periampullary cancer is unresectable because of either distant metastasis or local vascular involvement. The advent of gray scale and color Doppler ultrasonography has improved the ability of ultrasonography to detect vascular involvement. METHODS: Twenty-three consecutive patients with periampullary cancer were enrolled for prospective staging of their disease by comparing helical computed tomography and computed tomographic angiography with gray scale and color Doppler ultrasonography of the abdomen. Portal vein, superior mesenteric vein, splenic vein, and superior mesenteric artery involvement was graded 0 to 4, grade 0 being no vascular involvement and grade 4 being total occlusion of the vessel. Agreement between ultrasonography and computed tomographic angiography for determining vascular involvement was measured by chi2 analysis. RESULTS: Two patients (9%) were excluded because excessive overlying bowel gas hampered the ability of ultrasonography to visualize the pancreas. For the remaining 21 patients, there was significant agreement between ultrasonography and computed tomographic angiography for detecting vascular involvement in all vessels (P < .001; portal vein, kappa = 0.67; superior mesenteric vein, kappa = 0.67; splenic vein, kappa = 0.85; and superior mesenteric artery, kappa = 0.59). Ultrasonography was in agreement with computed tomographic angiography in all cases of unresectability. Both modalities were equally poor in preoperatively showing lymphadenopathy and metastases. CONCLUSIONS: Provided that there is adequate visualization on ultrasonography of the head of the pancreas in the periampullary region, then state-of-the-art gray scale and color Doppler ultrasonography are as accurate as helical computed tomography and computed tomographic angiography for detecting the unresectability of periampullary cancer. If performed as the initial investigation and the region of the pancreatic head is clearly shown, and if vascular encasement or occlusion or distant metastasis is identified, further investigations are unnecessary.

Adult↗
PubMed2000

Role of virtual computed tomographic colonography in patients with colorectal cancers and obstructing colorectal lesions.

PURPOSE: The aim of this study was to assess the ability of computed tomographic colonography to diagnose colorectal masses, stage colorectal cancers, image the proximal colon in obstructing colorectal lesions, and evaluate the anastomoses in patients with previous colorectal surgery. METHODS: We prospectively performed computed tomographic colonography examinations in 34 patients (20 males; mean age, 64.2; range, 19-91 years): 20 patients had colorectal masses (defined at endoscopy as intraluminal masses 2 cm or larger), 7 patients had benign obstructing colorectal strictures, and 7 patients had a prior colorectal resection. Final tumor staging was available in all 16 patients who had colorectal cancers and 15 patients were referred after incomplete colonoscopy. The ability of computed tomographic colonography to stage colorectal cancers, identify synchronous lesions in patients with colorectal masses, and image the proximal colon in patients with obstructing colorectal lesions was assessed. RESULTS: Computed tomographic colonography identified all colorectal masses, but overcalled two masses in patients who were either poorly distended or poorly prepared. Computed tomographic colonography correctly staged 13 of 16 colorectal cancers (81 percent) and detected 16 of 17 (93 percent) synchronous polyps. Computed tomographic colonography over-staged two Dukes Stage A cancers and understaged one Dukes Stage C cancer. A total of 97 percent (87/90) of all colonic segments were adequately visualized at computed tomographic colonography in patients with obstructing colorectal lesions compared with 60 percent (26/42) of segments at barium enema (P < 0.01). Colonic anastomoses were visualized in all nine patients, but in one patient, computed tomographic colonography could not distinguish between local tumor recurrence and surgical changes. CONCLUSION: Computed tomographic colonography can accurately identify all colorectal masses but may overcall stool as masses in poorly distended or poorly prepared colons. Computed tomographic colonography has an overall staging accuracy of 81 percent for colorectal cancer and is superior to barium enema in visualizing colonic segments proximal to obstructing colorectal lesions.

Adult↗
PubMed2000

Hepatic colon cancer metastases in mice: dynamic in vivo correlation with hypoechoic rims visible at US.

PURPOSE: To use videomicroscopy of tumor-bearing livers of live mice to depict tumors directly to determine the exact nature of rims seen on corresponding ultrasonographic (US) scans. MATERIALS AND METHODS: Seventy-six hepatic colorectal cancer metastases were studied in exteriorized livers of 18 mice by using intravital microscopy, US, and histologic examination of the same tumors. RESULTS: Hypoechoic rims correlated with distended sinusoidal spaces in vivo. These spaces surrounded only locally invasive tumors (mean diameter, 0.85 mm) that had obstructed the supplying terminal portal venules. These spaces, containing adherent leukocytes and tumor cells, gave rise to new tumor vasculature. Results of histologic examination of rims (portal inflammation, congested or compressed sinusoids, cell atrophy) correlated with leukocyte endothelial adherence, occluded sinusoids, and new vessel formation in vivo. CONCLUSION: Unlike results from previous studies, dynamic in vivo observations of peritumoral rims demonstrated distended sinusoidal spaces giving rise to new tumor-penetrating vessels. These sinusoids arose around locally invasive tumors and were associated with more advanced intrahepatic disease. These dynamic observations provide a pathophysiologic explanation for previous histologic correlates of peritumoral rims.

Analysis of Variance↗
PubMed2000

Percutaneous tumor ablation: increased coagulation by combining radio-frequency ablation and ethanol instillation in a rat breast tumor model.

PURPOSE: To determine if percutaneously applied radio frequency (RF) combined with percutaneous ethanol instillation (PEI) can increase the extent of ablation in rat breast tumors. MATERIALS AND METHODS: R3230 mammary adenocarcinoma was implanted bilaterally in the mammary fat pads of 18 female rats. The tumor nodules measured 1. 2-1.5 cm. Eight tumors each were treated with (a) conventional, monopolar RF (96 mA +/- 28; 70 degrees C for 5 minutes); (b) PEI (250 microL of ethanol infused over 1 minute); (c) combined therapy of PEI immediately followed by RF ablation; or (d) combined therapy of RF ablation immediately followed by PEI. Four tumors were not treated and served as controls. Histopathologic examination included staining for mitochondrial enzyme activity. Resultant coagulation necrosis was compared between treatment groups. RESULTS: Coagulation necrosis was observed only within treated tumors. Tumors treated with RF alone had 6.7 mm +/- 0.6 of coagulation surrounding the electrode, and those treated with PEI alone had 6.4 mm +/- 0.6 of coagulation around the instillation needle (not significant). Significantly increased coagulation of 10.1 mm +/- 0.9 (P: <.001) was observed with the combined therapy of PEI followed by RF. RF followed by PEI did not increase coagulation (6.4 mm +/- 0.8 around the needle; not significant). CONCLUSION: PEI followed by RF ablation therapy increases the extent of induced coagulation necrosis in rat breast tumors, as compared with either therapy alone.

Administration, Cutaneous↗
PubMed2000

Utility of intravenously administered contrast material at CT colonography.

PURPOSE: To determine if intravenously administered contrast material improves overall reader confidence in the assessment of the colon, large-bowel wall conspicuity, and diagnostic accuracy in the detection of colorectal polyps and cancers at computed tomographic (CT) colonography. MATERIALS AND METHODS: Two hundred patients underwent CT colonography in both supine and prone positions. A five-point scale was used to assess the effect of contrast enhancement on overall reader confidence and bowel wall conspicuity. Eighty-one patients underwent CT colonography with complete colonoscopic or surgical correlation; diagnostic accuracy was compared in 48 patients who received contrast material and 33 who did not. RESULTS: Bowel preparation was ideal in 38 (19%) of 200 patients. Enhanced prone CT images had significantly better scores for reader confidence (4.9 +/- 0.1 vs 4.6 +/- 0.1, P: <.005) and bowel wall conspicuity (4.6 +/- 0.2 vs 4.2 +/- 0.2, P: <.005) compared with those of nonenhanced prone images despite no significant difference in bowel distention (3.8 +/- 0.2 vs 3.9 +/- 0. 1, P: =.8). Enhancement significantly improved the ability to depict medium (6-9-mm) polyps (75% vs 58%, P: <.05). Three large (10-19-mm) polyps were detected only with contrast enhancement; two remained submerged despite dual positioning. CONCLUSION: The use of intravenously administered contrast material significantly improved reader confidence in the assessment of bowel wall conspicuity and the ability of CT colonography to depict medium polyps in suboptimally prepared colons.

Adult↗
PubMed2000

Radiologic features of complications arising from dropped gallstones in laparoscopic cholecystectomy patients.

OBJECTIVE: Because laparoscopic cholecystectomy has become the accepted treatment for symptomatic cholelithiasis, radiologists frequently encounter patients who have had this surgery. Although the radiologic features of postoperative bile duct injury are well documented, the imaging features of less well-known complications remain poorly described. One such unusual complication is abscess formation caused by dropped gallstones. CONCLUSION: Although the incidence of dropped gallstones is an uncommon complication of laparoscopic cholecystectomy, it should be recognized as a potential source of both intraabdominal and intrathoracic abscess formation in any patient presenting months to years after undergoing laparoscopic cholecystectomy. These abscesses are not necessarily confined to the right upper quadrant.

Abdominal Abscess↗