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Biomedical subjects

T C Winter

Publications and source records attributed to T C Winter.

53 records · Page 3Linked to original sources
PubMed1995

CT diagnosis of early hepatocellular carcinoma: sensitivity, findings, and CT-pathologic correlation.

OBJECTIVE: The purpose of this study was to determine the sensitivity of CT in detecting early hepatocellular carcinoma and to evaluate its CT appearance. An early hepatocellular carcinoma is a nodular lesion with no fibrous capsule composed of well-differentiated tumor histologically. It differs from a small hepatocellular carcinoma, which is an overt tumor that is moderately to poorly differentiated and has a fibrous capsule. Size is not a criterion for distinguishing between early and small hepatocellular carcinomas. MATERIALS AND METHODS: Thirty-one patients with 39 histopathologically proved early hepatocellular carcinomas (mean diameter, 1.7 cm) found by sonography, MR imaging, and/or intraoperative sonography were included in a retrospective study. We reviewed unenhanced CT scans of the entire liver in 30 patients (37 lesions) and early and late (35 sec and 5 min after the beginning of injection of contrast material) contrast-enhanced CT scans of the entire liver in all 31 patients (table incremental CT in 21; helical CT in 10; 39 lesions). Eighteen histologically proved small hepatocellular carcinomas (< or = 3 cm; mean diameter, 2.3 cm), present in the same patients, served for comparison. Histopathologically, nine patients had chronic hepatitis, and 22 had cirrhosis. RESULTS: The overall sensitivity of CT in detecting early hepatocellular carcinoma was 56%. These tumors were usually isodense with respect to surrounding liver on unenhanced, early enhanced, and late enhanced CT scans (iso-iso-iso). This pattern was seen in 17 (46%) of 37 lesions; thus, these 17 histologically proved early hepatocellular carcinomas were not detected with CT. An iso-iso-low density pattern was recognized in eight (22%), a low-low-low pattern in seven (19%), and several different patterns in five (13%) of the 37 lesions. Only two (5%) of 39 early hepatocellular carcinomas had a high-density appearance on early enhanced CT scans. In comparison, the most common pattern of small overt hepatocellular carcinomas on CT scans was low-high-low, seen in 17 lesions (94%) detected with CT. When the density of lesions on unenhanced CT scans was compared with the histopathologic appearance of the masses, low-density lesions showed mild to moderate fatty change and isodense lesions showed no or minimal fatty change (p = .006). CONCLUSION: The sensitivity of CT in detecting early hepatocellular carcinoma is poor (56%). However, the diagnosis of early hepatocellular carcinoma should be considered if CT scans show a small lesion with an iso-low or low-low density enhancement pattern on early and late contrast-enhanced CT scans, respectively, in patients with chronic liver disease.

Aged↗
PubMed1995

Association of sonographically detected subacromial/subdeltoid bursal effusion and intraarticular fluid with rotator cuff tear.

OBJECTIVE: Although an association between sonographically detected joint fluid and rotator cuff disease has been reported, the significance of sonographically detected subacromial/subdeltoid bursal effusion has not been studied. We examined a group of patients who had shoulder sonography and surgery to determine the association between bursal and joint effusion and surgically proved tears of the rotator cuff. MATERIALS AND METHODS: We retrospectively reviewed the preoperative shoulder sonography reports of 163 patients for the presence of fluid within the subacromial/subdeltoid bursa or glenohumeral joint. Surgical reports were obtained to determine the status of the rotator cuff. The sonographic reports of 232 asymptomatic shoulders were also reviewed to determine the prevalence of fluid within the subacromial/subdeltoid bursa or the glenohumeral joint. RESULTS: Sixty-seven (41%) of the 163 patients had a joint effusion, bursal fluid, or both. Joint effusion alone was seen in 35 patients. Fourteen of these had a normal rotator cuff at surgery, and 21 had a rotator cuff tear (sensitivity, 22%; specificity, 79%; positive predictive value, 60%). Bursal fluid alone was seen in 10 patients, seven of whom had a rotator cuff tear (sensitivity, 7%; specificity, 96%; positive predictive value, 70%). In 22 patients, fluid was seen in both the bursa and the joint; 21 had surgically proved rotator cuff tears (sensitivity, 22%; specificity, 99%; positive predictive value, 95%). Of the 232 asymptomatic shoulders, 16 (6.9%) had isolated joint effusions, eight (3.4%) had isolated bursal effusions, and four (1.7%) had both joint and bursal effusions. CONCLUSION: The sonographic finding of intraarticular fluid alone (without bursal fluid) has both a low sensitivity and a low specificity for the diagnosis of rotator cuff tears. However, the finding of fluid in the subacromial/subdeltoid bursa, especially when combined with a joint effusion, is highly specific and has a high positive predictive value for associated rotator cuff tears. Sonographically detected fluid in both the joint and the bursa is an uncommon finding in asymptomatic shoulders. The sonographic observation of fluid in the subacromial bursa, either isolated or combined with a joint effusion, should prompt a careful evaluation of the supraspinatus tendon for tear.

Acromion↗
PubMed1994

A comparison between preoperative magnetic resonance and intraoperative ultrasound tumor volumes and margins.

A major obstacle in surgical neuro-oncology is differentiating the interface between tumor and normal brain. Twenty-two brain tumors were evaluated preoperatively with magnetic resonance imaging. Intraoperative ultrasonography was used to guide surgical resection of these tumors, and results were compared with surgical and pathologic findings. Ultrasound tumor volume estimates were larger than T1 gadolinium-enhanced and T1 non-gadolinium-enhanced volumes, but these differences did not reach statistical significance. Similarly T2 volumes were larger than the corresponding sonographic volumes, except for the subset of low-grade gliomas, and in that instance the difference was small, but again the differences were not statistically significant. Ultrasonography enhanced identification of infiltrating tumor cells beyond falsely underestimated tumor margins as defined by T1 images. Ultrasound images helped differentiate edema as seen on T2 images from solid tumor and normal brain. The information gained from ultrasound images can be used to enhance tumor resection and improve patient survival and quality of life.

Adolescent↗
PubMed1994

Utility of magnetization prepared GRE MRI for the detection of focal liver lesions.

We compared the efficacy of rapidly acquired magnetization prepared gradient-echo (MP-GRE) sequences with CT and standard MRI pulse sequences for the detection of focal liver lesions. Fourteen patients with 28 focal liver lesions were scanned. TI times of 300, 450, and 600 ms were used. MP-GRE lesion conspicuity was compared to corresponding CT, T1, T2, T2-post-superparamagnetic-iron-oxide (SPIO), and STIR images. It was found that the differences between MP-GRE and CT and MP-GRE and T1 MRI were not significant. However, overall anatomic detail was better with CT and T1 MRI than MP-GRE. Lesion conspicuity was significantly worse with the MP-GRE than with the T2, T2-post-SPIO, and STIR sequences (all p values = 0.00). Maximal liver signal nulling occurred at TI = 300 ms in 13 out of 14 patients. However, the T1 for optimal focal liver lesion conspicuity varied widely and could not be predicted before scanning. No new lesions were seen on the MP-GRE sequence that could not be seen on the CT or standard MRI sequences. As currently implemented, MP-GRE imaging offers no advantage in the detection of focal liver lesions over CT and standard MRI pulse sequences.

Adult↗
PubMed1994

Early advanced hepatocellular carcinoma: evaluation of CT and MR appearance with pathologic correlation.

PURPOSE: To determine the computed tomographic (CT) and magnetic resonance (MR) imaging appearances of early advanced hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Twenty-seven surgically resected cases of early advanced HCC were studied with CT, CT during arterial portography, CT arteriography, and MR imaging. RESULTS: The sensitivity of standard CT (unenhanced, early, and late CT combined) for the detection of early advanced HCC was 81%, while that of standard MR imaging (T1- and T2-weighted MR imaging combined) was 83%. A nodule-in-nodule appearance was identified in approximately one-third to one-half of cases. Signal behavior of early and advanced components of early advanced HCC followed the expected behaviors of isolated early HCC and isolated advanced HCC, respectively. Tumor size was accurately estimated with standard CT and standard MR imaging. CONCLUSION: More research must be performed to ascertain whether any relationship exists between the different types of HCC and the clinical outcome.

Aged↗
PubMed1994

Testicular microlithiasis: imaging appearances and pathologic correlation.

PURPOSE: To determine the spectrum of sonographic findings, clinical implications, and pathologic correlation in patients with testicular microlithiasis (TM). MATERIALS AND METHODS: The cases of 42 patients with the characteristic appearance of TM on sonograms were retrospectively evaluated for the number, pattern, and distribution of echogenic foci and for associated intratesticular abnormalities. Medical records and pathologic reports were reviewed. RESULTS: Considerable variation was found in the number and distribution of occurrences of TM (five to 60 echogenic foci per transducer field). In some patients, peripheral clustering was seen. Most patients demonstrated side-to-side symmetry, but asymmetric distribution was seen in eight patients and unilateral foci were seen in one patient. In 17 patients, a germ cell neoplasm was seen. One additional patient had a focal lesion that was proved to be an infarct. CONCLUSION: TM has a characteristic sonographic appearance. Because of the 40% occurrence of primary testicular neoplasm in association with it, TM cannot continue to be considered a benign finding.

Adolescent↗
PubMed1994

Phase-contrast MR angiography of the portal venous system: preoperative findings in liver transplant recipients.

Sequential two-dimensional phase-contrast MR angiography can be used to accurately evaluate the anatomy, patency, and flow direction of the portal venous system and the presence, extent, and distribution of portosystemic collaterals. Its large field of view, insensitivity to the patient's body habitus, and graphic display format make this MR technique extremely useful for preoperative evaluation of patients with chronic liver disease and portal hypertension. This pictorial essay illustrates the spectrum of abnormalities seen on phase-contrast MR angiography of the portal venous system in patients with endstage liver diseases and portal hypertension.

Collateral Circulation↗
PubMed1993

Adverse reactions to intravenous contrast media in patients treated with interleukin-2.

Seventy patients consecutively admitted to a single institution were treated with high-dose interleukin-2 (IL-2) and analyzed for determining the incidence and risk factors associated with reactions to i.v. contrast media. Patients with metastatic renal cancer (n = 44) or melanoma (n = 26) received 74 cycles of IL-2 administered at 2 to 6 x 10(6) U/m2/d for 10-21 days either alone or with lymphokine-activated killer (LAK) cells or tumor-infiltrating lymphocytes (TILs). Seventy-four computed tomography (CT) scans were performed before administration of IL-2; and 74, 59, and 35 CT scans were performed, respectively, 2, 6, and 10 weeks after administration of IL-2. Of the 168 scans performed after therapy with IL-2, non-ionic media were used in 110 and ionic media were used in 58. There were no reactions before administration of IL-2, but there were nine reactions after therapy with IL-2. Reactions to contrast media occurred 1-4 hours after media infusion and included fever, chills, emesis, diarrhea, rash, wheezing, hypotension, edema, and oliguria. Hospitalization was required in seven cases, including intensive care unit support in four, but all patients recovered fully. Contrast reactions were more frequent 2 weeks after therapy with IL-2 (eight of 74 scans, 11%) compared with 6 weeks after IL-2 (one of 59 scans, 1.7%), but the difference was not statistically significant (McNemar's test). Six patients who reacted to contrast 2 weeks after IL-2 treatment received contrast 4 weeks later: five had no reaction and only one experienced a reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Hepatic teratoma in an adult. Case report with a review of the literature.

Teratomas of the liver in adults are rare. We believe this to be only the fifth such case reported, the first with CT correlation and with plain film documentation of the development and slow progression of the lesion from age 44 to 61. A review of the literature regarding hepatic teratomas is appended.

Calcification, Physiologic↗
PubMed1993

MR imaging with i.v. superparamagnetic iron oxide: efficacy in the detection of focal hepatic lesions.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of superparmagnetic iron oxide (SPIO) in the detection of focal hepatic lesions on MR images. SUBJECTS AND METHODS: The study included 21 patients with 115 focal hepatic lesions and eight patients without focal hepatic lesions. T1- and T2-weighted MR images were obtained at 1.5 T before and 60 min after the end of injection of an SPIO agent. Contrast-enhanced CT scans were obtained in all patients within 10 days after MR imaging. The effect of SPIO on the signal intensity of the liver and spleen was assessed by using quantitative analysis of the region of interest. Efficacy was evaluated by using multiple criteria and unenhanced and SPIO-enhanced images. Evaluations included subjective assessment of image quality, counting the number of lesions detected, and statistical analysis of quantitative changes in the signal intensity of lesions and of normal liver. RESULTS: By all criteria, SPIO-enhanced T2-weighted MR images were superior to unenhanced T2-weighted images and to contrast-enhanced CT scans. Conversely, by all criteria, SPIO-enhanced T1-weighted MR images were worse than unenhanced T1-weighted images and contrast-enhanced CT scans. The mean lesion-to-liver contrast on T2-weighted images was 317% on unenhanced images and 1745% on SPIO-enhanced images. For T1-weighted, the mean contrast was 26% on unenhanced images and 18% on SPIO-enhanced images. CONCLUSION: SPIO is an efficacious contrast agent for the detection of focal hepatic lesions when T2-weighted MR images are used.

Contrast Media↗
PubMed1983

The measurement of the kinetics of lipid phase transitions: a volume-perturbation kinetic calorimeter.

A volume-perturbation kinetic calorimeter to be used to study membrane phase transitions in lipid vesicles has been developed. In this instrument, the voltage-dependent extension of a stack of piezoelectric crystals is used to force the solution being studied to undergo a small adiabatic bidirectional volume change. This volume change induces a shift in the equilibrium position of the lipid gel to liquid-crystalline transition. The time course of the relaxation to the new equilibrium position is then monitored by observing the induced temperature and pressure changes as a function of time.

Calorimetry↗
PubMedDate not supplied

Low-attenuation oral GI contrast agents in abdominal-pelvic computed tomography.

BACKGROUND: We designed and evaluated a low-attenuation oral contrast agent for abdominal-pelvic computed tomography (CT). METHODS: In vitro studies, were performed initially to evaluate the imaging characteristics of multiple solutions. These studies resulted in two solutions being compared with the presently accepted oral CT agents of dilute iodinated contrast and water. Ninety-eight consecutive subjects already scheduled for routine outpatient abdominal-pelvic CT were enrolled. Subjects were randomized to water (n = 30), fiber solution (n = 32), polyethylene glycol (PEG; n = 11), or dilute iodinated solution (DI; n = 25). Examinations were then evaluated for gastric distention, small bowel distention, small bowel wall visualization, and colonic transit. A questionnaire was given to the study subjects for feedback concerning taste and potential side effects from these agents. RESULTS: PEG tended to provide better bowel distention, wall visualization, and colonic transit compared with water, fiber solution, and DI. Areas of statistical significance included: (1) average bowel diameter in the left upper quadrant for water was 17.50 mm, whereas that for PEG was 21.88 mm (p < 0.05); (2) average bowel diameter in the pelvis for water was 14.79 mm, that for fiber was 15.67 mm, and that for PEG was 18.48 mm (p < 0.05); (3) wall visualization was better with PEG than with fiber (p < 0.05); (4) successful transit of contrast to the colon occurred in every subject who received PEG compared with only 20% of those received water and 39% of those who received fiber (p < 0.05). Similar trends for the superiority of PEG over DI were noted, although many of these did not reach statistical significance. CONCLUSION: PEG solution has imaging characteristics related to bowel wall visualization, luminal distention, and colonic transit that make it an effective oral agent for abdominal pelvic CT examination.

Adolescent↗
PubMedDate not supplied

Impact of double helical CT and three-dimensional CT arteriography on surgical planning for hepatic transplantation.

BACKGROUND: To assess the impact of preliver transplant double helical computed tomography (DHCT) and three-dimensional computed tomography arteriography (3D-CTA) on surgical planning for hepatic transplantation. METHODS: Vascular findings detected on DHCT/3D-CTAs of 80 patients were shown to the transplant surgeon in a blinded fashion. These findings included hepatic arterial anatomy, diameters of the major vessels that supplied the liver, celiac axis stenosis, splenic artery (SA) aneurysms, and portal vein thrombosis (PVT). The surgeon was asked to state the "planned" surgical approach for each case based on scan findings. These results were subsequently compared with what "actually" occurred at transplantation by review of surgical records. RESULTS: Fifty-five patients had conventional and 25 patients had nonconventional hepatic arterial anatomy. Three patients had PVT, three patients had celiac axis stenosis, and three patients had SA aneurysms. Correlation between the "actual surgical technique" and the "planned surgical approach" was seen in 50/55 (91%) patients with conventional and in 23/25 (92%) patients with nonconventional anatomy. Five patients requiring aortohepatic interposition grafts for arterial anastomoses had either severe celiac axis stenoses or arterial inflow vessels that were 3 mm or smaller. Three patients with PVT underwent successful surgical resection of the thrombosed segment and standard PV anastomoses as planned. Patients with complete replacement of hepatic arterial supply to the superior mesenteric artery required alteration of the sequence of the vascular anastomoses. Patients with SA aneurysms had surgical ligation of the splenic artery. CONCLUSIONS: DHCT/3D-CTA provides noninvasive means to identify findings that have significant impact on surgical planning for hepatic transplantation including celiac axis stenosis, diameter of inflow arterial vessel </= 3 mm, complete replacement of hepatic arterial supply, PVT, and SA aneurysms.

Hepatic Artery↗
PubMedDate not supplied

Three-dimensional CT angiography of spontaneous portosystemic shunts.

Spontaneous portosystemic shunts (varices) are a well-known complication of severe liver disease and portal hypertension. Computed tomographic (CT) angiography was used to image the hepatic vasculature of 198 patients with end-stage liver disease in anticipation of liver transplantation. Performance of a delayed acquisition during the portal phase of enhancement enables evaluation of portal and variceal anatomy without the need for an additional injection of contrast material. Three-dimensional (3D) reconstruction of portal-phase CT angiograms enhances the perception of the courses and anatomic relationships of varices. This information is valuable for surgical planning. Common varices include the left gastric vein, short gastric veins, paraumbilical veins, and splenic vein; in cases of more unusual, complex shunts, 3D rendering is indispensable. By precisely demonstrating the courses of varices, CT angiography allows the surgeon to plan the operative approach and determine the need for surgical varix ligation or preoperative interventional embolization.

Angiography↗