Degree Of Contrast Enhancement Research Articles

MAGNETIC RESONANCE IMAGING FINDINGS IN HISTOLOGICALLY CONFIRMED PUG DOG ENCEPHALITIS

The purpose of the study was to describe magnetic resonance (MR) imaging features of histologically confirmed necrotizing encephalitis in four Pugs and to compare those findings with MR imaging characteristics of necrotizing encephalitis in other breeds. All dogs had the following common findings: lesions restricted to the forebrain, both cerebral hemispheres diffusely but asymmetrically affected, lesions affected gray and white matter resulting in loss of distinction between both, most severe lesions in occipital and parietal lobes, lesions were irregularly T2-hyperintense and T1-isointense to slightly T1-hypointense, and no cavitation. There were various degrees of contrast enhancement of brain and leptomeninges. Asymmetry of lateral ventricles and midline shift was seen in one dog each. Two dogs had brain herniation, which may have contributed to the progression of neurologic signs. Hyperintensity on T2-weighted and fluid attenuated inversion recovery images in the hippocampus and piriform lobe was consistent with excitotoxic edema, whereas similar imaging features in other forebrain areas corresponded to areas of inflammation or liquefaction on histopathology. In comparison with necrotizing encephalitis in other canine breeds, Pug dog encephalitis has some unique MR imaging features. Therefore, these characteristics cannot be applied to other breeds, nor should imaging features of necrotizing encephalitis of other canine breeds be used for interpretation of MR images in Pug dogs.

Standardized uptake values of uterine leiomyoma with 18F-FDG PET/CT: variation with age, size, degeneration, and contrast enhancement on MRI

To assess the effect of age, size, the degree of degeneration, and contrast enhancement on magnetic resonance imaging (MRI) on 18F-fluoro-2-deoxyglucose (18F-FDG) uptake in uterine leiomyomas using quantitative standardized uptake values (SUVs). A total of 61 leiomyomas of 41 patients, who underwent combined positron emission tomography/computed tomography (PET/CT) using 18F-FDG and contrast-enhanced MRI were included in this study. Sixty-one leiomyomas were divided into two groups: "non-degenerated" leiomyomas showing distinct low signal intensity on T2-weighted images and intermediate signal intensity on T1-weighted images, and "degenerated" leiomyomas showing other types of signal intensity. Sixty-one leiomyomas were also divided into two groups of "strongly enhancing" leiomyomas and "weakly enhancing" leiomyomas in terms of their degree of contrast enhancement on MRI. The mean values of the maximum and average SUVs for the total of 61 leiomyomas were 2.34 +/- 0.75 (range 1.59-5.15) and 1.74 +/- 0.50 (0.66-3.95), respectively. There was a moderate negative correlation between the maximum and average SUVs and age (r = -0.43 and P = 0.00016, r = -0.31 and P = 0.029, respectively). Although there was a mild positive correlation between maximum SUV and size (r = 0.35 and P = 0.011), there was no significant difference between average SUV and size. Although there was no significant difference in average SUV between "degenerated" and "non-degenerated" leiomyomas, the maximum SUV of "degenerated" leiomyomas was significantly higher than that of "non-degenerated" leiomyomas (P = 0.0012). The degree of contrast enhancement on MRI was not significantly correlated with 18F-FDG uptake. Mild or moderate uptake of 18F-FDG is often observed in uterine leiomyoma and declines with age, and should not be confused with malignant accumulation.

MAGNETIC RESONANCE IMAGING OF FELINE HIPPOCAMPAL NECROSIS

The clinical, neuropathologic, and magnetic resonance (MR) imaging features in four cats with necrosis of the hippocampus and piriform lobe are described. All cats had acute generalized seizures and behavioral changes including aggression, salivation, polyphagia, and disorientation. Routine hematologic, serum chemistry, and cerebrospinal fluid analyses were normal. MR imaging abnormalities were restricted to the area of the hippocampus and piriform lobe. The lesions were T2-hyperintense, T1-hypointense, and were characterized by various degrees of contrast enhancement. Lesions were consistent with necrotizing encephalitis. Two cats were euthanized and underwent postmortem examination within a week after MR imaging due to the lack of response to antiepileptic drug therapy and progressive encephalopathy [corrected] The remaining two cats lived for about four months and were then euthanized because of persistent behavioral and neurologic signs; only one of these cats underwent postmortem examination with histopathologic examination. Histopathological findings were typical of severe, diffuse, bilateral symmetric necrosis, and degeneration of neurons in the hippocampus and piriform lobe, but an etiologic agent was not apparent. This apparently unique feline syndrome, now reported in Switzerland and Italy, has no known cause at this time.

Multiple-Detector Computed Tomographic Angiography of Pancreatic Neoplasm for Presurgical Planning

To evaluate the degree of contrast enhancement, image quality, and accuracy of predicting resectability of pancreatic neoplasm with 16-row multiple-detector computed tomography (MDCT) angiography using low- and high-concentration (300 and 370 mg of iodine per milliliter, respectively) contrast media (CMs). Forty patients who had undergone pancreatic CT angiography (CTA) on 16-MDCT scanner and had surgery were included. Contrast medium of 2 iodine concentrations (group A, 300 mg/mL, n = 20; group B, 370 mg/mL, n = 20) from the same vendor (Isovue; Bracco Diagnostics), with iodine dose of 550 to 600 mg/kg of body weight, was injected at a rate of 5 mL/s. Dual-phase 16-row MDCT was performed using 1.25- and 5-mm collimation for the arterial and portal phases, respectively. For the quantitative analysis, Hounsfield units values in the aorta, superior mesenteric artery, portal vein, and pancreas during arterial and venous phases were measured. Two readers subjectively rated the overall image enhancement, 3-dimensional image quality, and lesion and pancreatic duct conspicuity. Accuracy of lesion resectability was also established for each patient. The data were compared using Student t test for statistical analysis. The quantitative analysis for the degree of enhancement (Hounsfield unit) of the aorta, superior mesenteric artery, and pancreas during the arterial phase demonstrated similar values in groups A (low-concentration CM) and B (high-concentration CM), with no statistically significant difference with each other (P > 0.05). During the portal venous phase, we found superior enhancements in the superior mesenteric and portal veins in group A (P < 0.05). The qualitative assessments of the overall image enhancement and 3-dimensional image quality on a 5-point scale were 4.3 and 4.65, respectively (P < 0.05), in group A and 4.6 and 4.75, respectively, in group B, whereas on a 3-point scale, the pancreatic duct display and lesion conspicuity were 2.75 and 2.85, respectively, in group A and 2.9 and 2.9, respectively, in group B. The accuracy for lesion resectability was 95% (19/20) in group A and 100% (20/20) in group B (P > 0.05). Both CMs demonstrated comparable performance for 16-row MDCT of the pancreas for presurgical planning. However, high-concentration CM (370 mg of iodine per milliliter) provides higher overall enhancement and superior-quality 3-dimensional images with a shorter injection duration.

Splenic rupture as the presenting manifestation of primary splenic angiosarcoma in a teenage woman: a case report

IntroductionPrimary splenic angiosarcoma is a rare neoplasm of vascular origin carrying a very poor prognosis, partly due to its high metastatic potential. This disease presents frequently with splenic rupture and hemorrhage. We report the case of a 17-year-old woman who presented with rupture of a primary splenic angiosarcoma.Case presentationThe patient presented with diffuse abdominal pain and distention. Clinical examination revealed severe tenderness in the left upper abdominal quadrant, a palpable abdominal mass, and hemodynamic instability with a systolic arterial blood pressure of 75 mmHg and heart rate of 135 beats per minute. Blood tests revealed anemia (hemoglobin 7.0 g/dl) and thrombocytopenia (platelets 70 × 109/liter). After initial fluid resuscitation and stabilization, abdominal ultrasound and computed tomography were performed, revealing a large quantity of intraperitoneal free fluid, an enlarged spleen, and a heterogeneous low-density signal within the splenic parenchyma, which showed varying degrees of contrast enhancement. At laparotomy a huge (weight 1530 g, diameter 19 cm) actively bleeding spleen was identified and splenectomy was performed. Histopathology showed a primary splenic angiosarcoma. After an uneventful recovery, the patient was discharged on the sixth postoperative day.ConclusionPrimary splenic angiosarcoma is rare. Although this malignancy is usually encountered in advanced age, there have been a few reported cases among younger patients. The case reported here presented with splenic rupture, was treated by laparotomy and splenectomy, and the patient is disease free 16 months after surgery.

Iodized Oil Accumulation in Hypervascular Hepatocellular Carcinoma after Transcatheter Arterial Chemoembolization: Comparison of Imaging Findings with CT during Hepatic Arteriography

To compare the degree of tumor enhancement seen on computed tomography (CT) during hepatic arteriography (CT/HA) performed before transcatheter arterial chemoembolization (TACE) versus that determined based on the accumulation of iodized oil seen on CT images obtained after TACE in patients with hypervascular hepatocellular carcinoma (HCC) and evaluate the discrepancy in findings between the two imaging modalities (more or less oil accumulation after TACE compared with enhancement on CT/HA). CT/HA, TACE, and iodized oil CT after TACE were performed in 69 patients with 83 hypervascular HCCs with use of an interventional CT system. The degree of contrast enhancement of the lesion on CT/HA and the iodized oil accumulation on unenhanced CT after TACE were compared. Among 83 HCCs, the degree of enhancement on CT/HA before TACE corresponded to the iodized oil accumulation on CT in 56 (67.5%). Fifteen of 83 HCCs (18%) showed incomplete or poor accumulation of iodized oil despite good enhancement on CT/HA images. Twelve of 83 HCCs (14.5%) showed moderate or complete accumulation of iodized oil despite poor or no enhancement on CT/HA images. In particular, in two patients with occluded portal veins, iodized oil did not accumulate in the tumor despite good visualization on CT/HA. Although iodized oil accumulation in hypervascular HCCs correlates with the degree of lesion enhancement on CT/HA in most cases, a discrepancy may occur in a substantial number of cases, which likely affects the prediction of therapeutic effects in hypervascular HCCs.

MR T1-Weighted Inversion Recovery Imaging in Detecting Brain Metastases: Could It Replace T1-Weighted Spin-Echo Imaging?

T1-weighted inversion recovery (T1IR) imaging demonstrates higher brain tissue contrast and is more sensitive to contrast enhancement than T1-weighted spin-echo (T1SE) imaging. However, the effectiveness of the 2 imaging sequences in detecting brain metastases has not been studied. The objective of this report was to determine which sequence should be used for detecting brain metastases by comparing the effectiveness of T1IR imaging with that of T1SE imaging. Thirty-one patients with brain metastases underwent T1SE and T1IR with and without intravenous gadopentetate dimeglumine. T1SE and T1IR images were compared for the number of metastases, degree of contrast enhancement, volume and contrast-to-enhancement ratio (CER) of tumors, and contrast ratio (CR) of tumor to white matter (WM), tumor to gray matter (GM), and tumor to CSF. There were 352 metastases in 31 patients, among which 2 patients with 5 metastases were demonstrated only on postenhanced T1SE images. Pre-enhanced and postenhanced T1SE images detected 162 and 350 lesions, respectively, whereas pre-enhanced and postenhanced T1IR images only discovered 94 and 233 lesions. The degree of tumor contrast enhancement was higher on T1IR images than on T1SE images, whereas no difference in the CER of tumors was found between the 2 sequences. Before enhancement, all of the CRs on T1IR images were higher than on T1SE images. After contrast enhancement, CRs of tumor to WM and tumor to GM were higher on T1SE images than on T1IR images. On the contrary, the CR of tumor to CSF was higher on T1IR images than on T1SE images. Tumor volumes were 5.6 +/- 7.0 cm(3) on postenhanced T1SE images and 5.5 +/- 7.0 cm(3) on postenhanced T1IR images, and no significant difference was found between the 2 groups. T1SE, but not T1IR, should be used as T1-weighted imaging in detecting brain metastases, because T1SE imaging has a greater sensitivity than T1IR imaging both before and after contrast material administration.

Saline Flush Effect for Enhancement of Aorta and Coronary Arteries at Multidetector CT Coronary Angiography

To prospectively investigate the effect of the injection rate of a saline solution as a bolus chaser for the enhancement of the aorta and coronary arteries at multidetector computed tomographic (CT) coronary angiography. Institutional review board approved this study, and all patients gave informed consent. One hundred consecutive patients (59 men, 41 women; mean age, 58 years +/- 11 [standard deviation]) underwent 64-section CT coronary angiography for coronary artery disease. They were divided into five groups (each group, n = 20) according to the injection rate of saline solution (3, 4, 5, 6, and 7 mL/sec). Iodinated contrast medium (60 mL) was injected intravenously at a rate of 4 mL/sec, followed by 60 mL saline solution administered intravenously at a rate of 3-7 mL/sec, depending on the groups. Attenuation values of the aortic root, right coronary artery, left anterior descending artery, and left circumflex artery were measured. Analysis of variance with the Scheffé method was used to evaluate statistical significance of the differences in attenuation according to the injection rate of saline solution. The degree of contrast enhancement was affected by the injection rate of saline solution, and the attenuation values were higher as the injection rate increased up to 4-5 mL/sec (P < .05). The values plateaued at rates over 5 mL/sec in the aorta and over 4 mL/sec in the coronary arteries. An injection rate of 4-5 mL/sec as a saline solution chaser is optimal for achieving maximum attenuation values of the aorta or coronary arteries by using 64-section CT with 60 mL contrast material.

Lateral ventricle gliomas and central neurocytomas in adults diagnosis and perspectives

Neuroimaging data of lateral ventricle gliomas and central neurocytomas diagnosed in one institution were reviewed and compared to the corresponding literature data. CT and MRI imaging characteristics of the two tumour types are rather different, both in reported cases as well as in our material. In our series ventricular ependymomas (eight cases) were mostly hyperdense with pronounced contrast uptake. Thirteen subependymomas were hypodense, mostly without enhancement, but occasionally mild or moderate enhancement was noted. Eight subependymal giant cell astrocytomas also displayed hypodense, rarely hyperdense or mixed imaging characteristics, and always showed significant degree of contrast enhancement. Nineteen central neurocytomas showed hypo- or mixed density, but mostly mild to moderate enhancement. Ependymomas and anaplastic astrocytomas and glioblastomas followed the characteristics of the similar extraventricular ones. In our series low-grade astrocytomas, WHO I–II [Louis DN, Ohgaki H, Wiestler OD, Canevee WK. WHO classification of tumours of the central nervous system. Lyon: International Agency for Research on Cancer; 2007] were hypodense without contrast uptake. Our data support those of previous studies in that MRI has been found to be superior to CT for a more precise imaging of lateral ventricle gliomas. However, it is of note that for the verification of an intraventricular tumour CT is also satisfactory. Survival data were available in 65 cases, which have confirmed a favourable outcome in most of the patients with subependymoma, subependymal giant cell astrocytoma, central neurocytomas or pilocytic astrocytoma. Survival of patients with other types of glial tumour was similar to that of patients with a similar tumour, but in an extraventricular localisation.

Differentiation of soft tissue lipoma from well-differentiated liposarcom on MRI

目的 评价MRI征象在诊断软组织脂肪瘤和分化良好型脂肪肉瘤中的价值.方法 回顾分析经病理证实的22例软组织脂肪瘤和8例分化良好型脂肪肉瘤患者的MRI资料,比较2类肿瘤在大小、脂肪成分所占比例、厚分隔、结节或片状非脂肪成分、边缘及强化情况方面的差异.结果 脂肪瘤和分化良好型脂肪肉瘤的直径分别为(64±35)和(138±44)mm(t=4.263,P＜0.01),脂肪成分所占比例分别为(94±6)%和(74±9)%(t=5.903,P＜0.01).3例脂肪瘤和所有分化良好型脂肪肉瘤有2个以上厚分隔(P＜0.01);结节或片状非脂肪成分见于4例脂肪瘤和全部分化良好型脂肪肉瘤(P＜0.01).行抑脂增强扫描的15例脂肪瘤中,仅有4例显示轻到中度强化,而分化良好型脂肪肉瘤中1例呈中度强化,7例呈明显强化(P＜0.01).脂肪瘤全部边界清楚,分化良好型脂肪肉瘤1例边界不清(P＞0.05).结论 MRI有助于鉴别软组织脂肪瘤和分化良好型脂肪肉瘤,与脂肪瘤相比,分化良好型脂肪肉瘤体积多较大,脂肪成分相对较少,多有2个以上的厚分隔以及结节和(或)片状非脂肪成分,且强化明显。

Has the Degree of Contrast Enhancement with MR Imaging in Laryngeal Carcinoma Added Value to Anatomic Parameters Regarding Prediction of Response to Radiation Therapy?

Our aim was to retrospectively investigate the prognostic significance of the degree of contrast enhancement in tumors and its additional value in previously considered MR imaging parameters with regard to local control of laryngeal cancer treated with radiation therapy (RT) alone. Pretreatment MR images of 64 consecutive patients (54 men and 10 women, 43-80 years of age) with supraglottic and glottic cancer were retrospectively reviewed on clinical and previously considered MR imaging parameters such as tumor involvement of specific laryngeal anatomic subsites, including laryngeal cartilages, tumor volume, extralaryngeal tumor spread, and, in addition, the degree of contrast enhancement. Clinical and MR imaging parameters were associated with regard to local control at 2 years by using the Cox regression model. "Local control" was defined as absence of primary tumor recurrence. When using a threshold of the mean average contrast enhancement of 77%, the 2-year local control rate in the groups of patients with a degree of enhancement below and above this threshold was 57% and 70%, respectively (P=.3). Enhancement of tumor tissue in pre-epiglottic space (PES) was low, most probably due to its adipose tissue and poor vascular content, whereas tumor tissue involving paraglottic space (PGS) did enhance. Results of multivariate analysis indicated that the degree of contrast enhancement yielded the prognostic information (P=.07) with 2 independent prognostic factors: primary tumor volume (P=.007) and subglottic extension (P=.002) with regard to local control. Using these previously mentioned 3 MR imaging parameters as potential risk factors, we defined 4 categories, resulting in the following local control rates respectively: 90% for the group without risk factors, 73% for the group with 1, 60% for the group with 2, and finally 0% for the group with 3 risk factors, which was significantly lower than the rates in previous risk groups (P < .001). PES has a lower degree of contrast enhancement than the PGS and may correlate with the worse outcome. Including a low degree of contrast enhancement as a parameter to primary tumor volume and subglottic extension may increase the predictive value of MR imaging for local outcome and may be helpful to identify a subset of patients whose tumors all recurred locally within 2 years after primary RT.

Treatment of gliomatosis cerebri with temozolomide: A retrospective study of the AINO (Italian Association for Neuro- Oncology)

2033 Background: The optimal management for patients with primary gliomatosis cerebri is unknown, and some recent studies suggest that temozolomide could be useful as an upfront treatment. Methods: Between 1999 and 2005, 46 patients with biopsy proven gliomatosis cerebri were treated with temozolomide either upfront or at progression after prior radiotherapy/chemotherapy. Histological diagnoses were as follows: glioblastoma in 3 patients, malignant glioma in 8, anaplastic astrocytoma in 8, gemistocytic astrocytoma in 2, astrocytoma in 13, anaplastic oligodendroglioma in 1, anaplastic oligoastrocytoma in 1, oligoastrocytoma in 1, oligodendroglioma in 4, glial proliferation consistent with GC in 5. Median age was 49 years (range 14–70), with 20 males and 26 females and a median KPS at diagnosis of 80 (range 50–90). Twenty-three out of 46 (50%) pre-treatment MRI demonstrated some degree of contrast enhancement. Twenty-three of 46 patients were treated upfront, while 23 had received prior radiation therapy or nitrosourea-based chemotherapy. All patients received temozolomide 200 mg/m2 die for 5 days every 4 weeks until progression or unacceptable toxicity. Response was evaluated, according to Macdonald criteria, on T1-weighted with Gadolinium and FLAIR images. Results: Two patients (4%) showed a CR of the contrast enhancing area, 2 patients (4%) a PR, 5 (11%) a minor response, 18 (39%) a SD and 19 (42%) a PD. Overall response rate (CR + PR + “minor response”) was 19%, while a clinical benefit was observed in 13/46 patients (28%). Median TTP was 9 months (range 1–27), and median survival 14 months (range 3–123). PFS at 6 months was 57%, at 12 months 35%. Oligodendroglial tumours showed a 38% response rate and a TTP of 11 months. Response rate was higher among patients treated at progression compared to those treated upfront (13% versus 26%). Grade III-IV haematological toxicity was mild. Conclusions: Temozolomide has some activity in primary GC (19% response rate), and is well tolerated. A significant neurological improvement can be observed in patients with either response or stable disease on MRI. To improve the efficacy of temozolomide in the upfront setting (in order to delay a large field RT), a phase II study with a dose-dense regimen is ongoing. No significant financial relationships to disclose.

Breast fibroadenoma: comparative study of pathological features with varied MRI findings

目的 观察乳腺纤维腺瘤的多种MRI表现,分析其病理基础,从而加深对纤维腺瘤的认识,提高MRI诊断准确率.方法 对33例乳腺纤维腺瘤患者(38个病灶),行常规MR平扫和动态增强检查.所有病例均经病理证实,分析比较病灶的MRI形态学、信号强度及其动态增强特点等.结果 33例38个乳腺纤维腺瘤的形态学表现以分叶状、类圆形为主,占89.5%(34/38).MRI显示内部信号多较均匀,T1 WI呈等、低信号,T2 WI信号多样化,高信号者的黏液样变明显(平均指数1.9),间质细胞丰富(平均指数2.2);呈低信号者间质多硬化,间质细胞分布稀疏.不同信号强度的2种指数差异有统计学意义(x2值分别为11.267、10.415,P值均＜0.05).肿瘤有完整的包膜,边界多清晰者占86.8%(33/38).增强后无或轻度强化(5/38)、明显强化(33/38);不同强化曲线的2种指数差异无统计学意义(x2=1.171、2.861,P＞0.05).强化程度与患者的年龄构成有一定的相关性,年龄较轻者,强化多明显.无强化分隔者(9/33),是由于瘤体内部间质纤维组织胶原化形成.结论 乳腺纤维腺瘤的MR T2 WI信号及强化程度表现多样化,和其瘤体内黏液硬化程度及间质细胞含量相关.认识纤维腺瘤的特征性MRI表现有助于鉴别诊断。

Evaluation of Renal Transplant Donors with 16-Section Multidetector CT Angiography: Comparison of Contrast Media with Low and High Iodine Concentrations

To compare the degree of contrast enhancement, image quality, and accuracy of renal computed tomographic (CT) angiography performed with a 16-detector row CT unit and equal iodine doses of low- and high-iodine-concentration contrast medium in the evaluation of renal transplant donors. Eighty donors scheduled to undergo renal CT angiography with 16-detector row CT were administered nonionic contrast media with two iodine concentrations. The first group (group A, n=40) received a contrast medium with 300 mg of iodine per milliliter, and the second group (group B, n=40) received a contrast medium with 370 mg of iodine per milliliter. An equal iodine dose of 550 mg per kilogram body weight was given to both groups. Contrast enhancement was quantified by measuring attenuation in the abdominal aorta and in both renal arteries. Subjective assessment of contrast enhancement, quality of reformatted images, and visualization of branch order of renal arteries were rated with a 5-point scale. The number of renal arteries and veins seen at CT was correlated with the results at surgery. The mean enhancement values in group B were significantly greater (P<.001) than those in group A. The mean HU (+/-standard deviation) in groups A and B were 298+/-76 and 344+/-75, respectively, in the aorta, 284+/-74 and 331+/-71 in the right renal artery, and 285+/-72 and 329+/-73 in the left renal artery. The mean enhancement, image quality, and branch orders visualized were rated better in group B than in group A (P<.01). The accuracies for correctly identifying renal arteries and veins, respectively, were 91% and 95% for group A and 96% and 96% for group B. Renal donor CT angiography with a contrast medium of 370 mg of iodine per milliliter provides greater enhancement and image quality compared with a contrast medium of 300 mg of iodine per milliliter. The diagnostic accuracies were similar.

Poorly Versus Moderately Differentiated Hepatocellular Carcinoma

To determine the vascularity of moderately and poorly differentiated hepatocellular carcinoma (mHCC and pHCC, respectively) as observed on and depicted by computed tomography during hepatic angiography and to perform pathological correlation. Eighty-seven consecutive patients with 89 hepatocellular carcinomas (61 mHCCs and 28 pHCCs) were surgically resected in our hospital. The degree of contrast enhancement on computed tomography during hepatic angiography of the tumors was classified into high attenuation (H), isoattenuation (I), and low attenuation (L). We also examined hepatocellular carcinomas measuring less than 4 cm in diameter. Pathologically, the number of unpaired arteries in the tumors was determined (x200 magnification). The number of mHCC and pHCC in each degree of enhancement (H/I/L) was 59:1:1 and 19:6:3, respectively. The number of mHCC and pHCC measuring less than 4 cm without portal invasion was 48 and 15, respectively; the number of these tumors in each degree of enhancement (H/I/L) was 47:1:0 and 11:3:1, respectively. The mean number of unpaired arteries was 8.9 +/- 4.4 in mHCC and 5.2 +/- 4.3 in pHCC, respectively. All results were statistically significant (P < 0.01). Our results indicated that the arterial blood supply of pHCC was lower than that of mHCC.

Expression of Caveolin in Hepatocellular Carcinoma: Association with Unpaired Artery Formation and Radiologic Findings

Hepatocellular carcinoma (HCC) is becoming one of the common malignant tumors worldwide, and it is characterized by its high vascularity. Caveolin is the major structural protein in caveolae, which are small omega-shaped invaginations within the plasma membrane. Caveolin has been implicated in mitogenic signaling, oncogenesis and angiogenesis. The expression of caveolin-1 and -2 in HCC and its potential relationship with angiogenesis has not been examined. Paraffin sections of 35 HCC specimens were immunostained with caveolin-1, caveolin-2, alpha-smooth muscle actin, and CD34 antibodies. In addition, the expression of caveolin-1 and -2 mRNA in HCC was examined. The relationship between the radiological findings and the number of unpaired arteries and microvessel density (MVD) was also investigated. Caveolin-1 and -2 were expressed in the sinusoidal endothelial cells in 20 out of 35, and 18 out of 35 HCC specimens, respectively. Caveolin-1 and -2 were also expressed in the smooth muscle cells of the unpaired arteries in 26 out of 35, and 18 out of 35 HCC specimens, respectively. Increased expression of caveolin-1 and -2 mRNA was detected in 26.7% and 33.3% of the tumor specimens, respectively, compared with the corresponding non-tumorous adjacent liver tissues. There was a significant correlation between expression of caveolin-1, -2 in the smooth muscle cells of unpaired arteries and the number of unpaired arteries. The number of unpaired arteries in HCCs was found to be associated with the degree of contrast enhancement in the arterial phase imaging. However, it did not correlate with the degree of MVD. These findings suggest that the expression of caveolin-1, -2 is associated with the formation of unpaired arteries in HCC. In addition, there is a correlation between the degree of contrast enhancement of the HCC in the arterial phase image and the number of unpaired arteries.

A Clue for the Diagnosis of Lung Cancer Looking Lobar Consolidation with Emphasis on Thickness and Enhancement Pattern of Bronchial Wall on CT

Purpose: To differentiate between lung cancer and pneumonia for cases of lobar consolidation, with an emphasis on the thickness and enhancement pattern of the bronchial wall viewed by a CT. Materials and Methods: We retrospectively analyzed 17 patients with evidence of lobar consolidation, from a simple-chest radiograph, and divided them into groups by condition (lung cancer, n = 5; pneumonia, n = 12). CT scans were performed on all patients and bronchial wall thickness, which is the cranio-caudal length of the bronchial wall thickness and the enhancement pattern, were measured and analyzed at the mediastinal window setting. Results: The thickness of the bronchial wall in the lung cancer group (2.46±0.37 mm) was significantly greater than the pneumonia group (1.73±0.36 mm) (p = 0.002). Moreover, the bronchial wall thickness was greater than 2.0 mm for all patients in the cancer group. Further, if a diagnostic criterion was set to be larger than 2.0 mm, 100% sensitivity and 66.7% specificity would be achieved for the study subjects. The cranio-caudal length of the bronchial wall thickness in the cancer group was 37.5±16.4 mm, which was significantly greater than the pneumonia group (16.3±6.6 mm) (p = 0.001). We found no significant difference for the degree of contrast enhancement between the two groups. Conclusion: A CT scan measurement of the bronchial wall thickness greater than 2 mm in CT scans can be an indicator for diagnosing lung cancer in patients with lobar consolidation.

Correlation of Relative Permeability and Relative Cerebral Blood Volume in High-Grade Cerebral Neoplasms

The purpose of this study was to correlate the degree of contrast enhancement on dynamic contrast-enhanced T1-weighted MRI and the relative cerebral blood volume (rCBV) values on T2*-weighted MRI in patients with high-grade brain neoplasms. Ten patients with biopsy-proven high-grade gliomas underwent dynamic contrast-enhanced MRI using T1-weighted fast spoiled gradient-echo technique (TR/TE, 8.3/1.5) during i.v. infusion of 0.1 mmol/kg of MR contrast medium. This sequence was followed within 5 minutes by dynamic susceptibility contrast (DSC) imaging (1,500/80) during i.v. infusion of 0.2 mmol/kg of MR contrast medium. Dynamic contrast-enhanced analysis was performed using the maximum-signal-intensity algorithm, and DSC analysis was performed using the negative enhancement integral program. For each tumor, we performed two comparisons: first, the average dynamic contrast-enhanced and rCBV values within a region of interest drawn around the entire contrast-enhancing tumor on a single image through the center of the lesion and, second, the highest dynamic contrast-enhanced and highest rCBV values within each tumor. Statistical analyses of the first comparison were performed using Pearson's correlation coefficient, R2 correlation coefficient, and Spearman's rank correlation and for the second comparison using Kendall's tau correlation. The mean signal intensity values ranged between 3.48 and 7.16 SDs above baseline values (mean, 4.89 SDs). The mean rCBV values ranged between 57.9% and 122.7% of the normal lentiform nucleus (mean, 76.6%). The Pearson's correlation coefficient was 0.867, the R2 correlation coefficient was 0.752, and the Spearman's rank correlation was 0.794 (p = 0.001). Dynamic contrast-enhanced values from the region of highest signal intensity ranged between 7.7 and 48.6 SDs above baseline values (mean, 17.3 SDs). The highest rCBV values ranged between 105% and 400% of the normal lentiform nucleus (mean, 292%). The correlation was estimated to be 0.7778 and was statistically significant at the 0.01 level of statistical significance (p = 0.0035). We found a high correlation between degree of contrast enhancement on dynamic contrast-enhanced images and rCBV values in whole tumors and in regions having the highest degree of contrast enhancement in this small study. Our findings, which suggest that relative permeability and rCBV values may be correlated in high-grade glial neoplasms, deserve further study in a larger patient population.

Reducing the influence of spatial resolution to improve quantitative accuracy in emission tomography: A comparison of potential strategies

The goal of this paper is to compare strategies for reducing partial volume effects by either minimizing the cause (i.e. improving resolution) or correcting the effect. Correction for resolution loss can be achieved either by modelling the resolution for use in iterative reconstruction or by imposing constraints based on knowledge of the underlying anatomy. Approaches to partial volume correction largely rely on knowledge of the underlying anatomy, based on well-registered high-resolution anatomical imaging modalities (CT or MRI). Corrections can be applied by considering the signal loss that results by smoothing the high-resolution modality to the same resolution as obtained in emission tomography. A physical phantom representing the central brain structures was used to evaluate the quantitative accuracy of the various strategies for either improving resolution or correcting for partial volume effects. Inclusion of resolution in the reconstruction model improved the measured contrast for the central brain structures but still underestimated the true object contrast (∼0.70). Use of information on the boundaries of the structures in conjunction with a smoothing prior using maximum entropy reconstruction achieved some degree of contrast enhancement and improved the noise properties of the resulting images. Partial volume correction based on segmentation of registered anatomical images and knowledge of the reconstructed resolution permitted more accurate quantification of the target to background ratio for individual brain structures.

Comparison of Enhancement, Image Quality, Cost, and Adverse Reactions Using 2 Different Contrast Medium Concentrations for Routine Chest CT on 16-Slice MDCT

To evaluate the degree of enhancement and image quality of chest computed tomographic (CT) examinations on 16-slice multidetector CT using low-concentration [300 milligrams of iodine per milliliter (mg I/mL)] and high-concentration (370 mg I/mL) contrast media; to assess the impact on cost and adverse reactions of the use of high-iodine concentration contrast medium. A total of 100 patients scheduled for routine chest CT examinations were administered nonionic contrast medium of 2 strengths: low-iodine concentration contrast medium (300 mg I/mL) [group A: n = 50; male-female ratio, 28:22; mean age, 58.4 years] and high-iodine concentration contrast medium (370 mg I/mL) (group B: n = 50; male-female ratio, 18:32; mean age, 57.6 years) with a constant amount of iodine (400 mg) injected per kilogram of body weight. Contrast media were injected using a dual injector at 2.5 mL/s followed by a 30-mL saline at 2.5 mL/s. The degree of enhancement was quantified by measuring Hounsfield unit values in different arteries and veins and was also rated on a 5-point scale for qualitative assessment. We also evaluated perivenous contrast-related artifacts. The data were compared using Mann-Whitney U test for both qualitative and quantitative enhancement ratings. A value of less than 0.05 was considered statistically significant. The value was adjusted using Bonferroni correction for statistical significance when multiple comparisons were performed. The difference in cost and the incidence of adverse reactions in both groups were calculated. The mean enhancement values in group B were significantly greater (P < 0.05) than those in group A. The mean Hounsfield units and standard deviation in groups A and B were aorta = 153 +/- 4, 216 +/- 20; pulmonary artery = 147 +/- 10, 208 +/- 20; superior vena cava = 155 +/- 27, 299 +/- 72; and pulmonary vein = 134 +/- 10, 215 +/- 30, respectively. The mean enhancement on a 5-point scale was greater in group B (4.2) than in group A (3.3) (P < 0.01). No significant difference between groups in perivenous artifacts was seen. Up to 5.5% savings in cost resulted from the use of a higher concentration of iodine, with no increase in adverse reactions. Use of higher-concentration contrast media provides a higher degree of contrast enhancement and image quality for a routine chest CT on a 16-slice multidetector CT. It also contributes to considerable cost savings with no increased risk of adverse reactions compared with low-concentration contrast media.