Min-Chi Chen

Small Bowel Intussusception in Symptomatic Pediatric Patients: Experiences with 19 Surgically Proven Cases

Nineteen cases of surgically proven symptomatic pediatric small bowel intussusceptions (SBI) were retrospectively reviewed. Clinical presentations included vomiting (89.5%), abdominal pain and/or irritable crying (89.5%), fever (52.6%), bloody stools (26.3%), palpable abdominal masses (15.8%), hematemesis (10.5%), jaundice (5.3%), and seizures (5.3%). The duration between symptom onset and hospitalization ranged between 20 and 336 hours (average 75.8 hours). Two patients with suspected appendicitis and small bowel obstruction were operated on promptly. Sonograms revealed target lesions (average diameter 2.9 cm) suggestive of intussusception in 13 out of 17 patients, with 10 lesions located in the paraumbilical or left abdominal regions. Barium enemas in 12 of these 13 patients demonstrated no colonic lesions. Diagnosis and surgery were delayed in 16 patients (average delay = 32 hours). The remaining 1 patient with positive sonographic findings underwent early surgery after computed tomographic (CT) confirmation of SBI. Surgery revealed ileoileal intussusceptions in 11 patients, jejunojejunal in 4, jejunoileal in 3, and duodenojejunal in 1. Eight patients had lead points. Bowel complications (ischemia, necrosis, or perforation) occurred in 8 patients. The duration between symptom onset and surgery in patients with bowel complications was significantly longer than for patients without complications (p = 0.0026). In conclusion, delayed diagnosis and surgical treatment in symptomatic pediatric patients with SBI were common, leading to a high rate (42%) of bowel complications. Sonographic demonstration of a 2–3 cm target lesion, especially if paraumbilical or left abdominal, is suggestive of SBI and may obviate the need for a barium enema; however, CT is helpful for confirming SBI. In symptomatic SBI, once diagnosed, early surgical referral is strongly recommended.

Pretreatment evaluation of distant-site status in patients with nasopharyngeal carcinoma: accuracy of whole-body MRI at 3-Tesla and FDG-PET-CT

We sought to prospectively evaluate the accuracy of 3.0-Tesla whole-body magnetic resonance imaging (WB-MRI) and integrated fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) (FDG-PET-CT), and their combined interpretation for the assessment of distant-site status in 150 patients with untreated nasopharyngeal carcinoma (NPC). Eighteen (12%) patients were diagnosed as having distant malignancies (15 patients had distant metastases, and three distant synchronous tumours). On a patient-based analysis, WB-MRI and FDG-PET-CT showed similar sensitivity (77.8% vs 72.2%, P > 0.999), specificity (98.5% vs 97.7%, P > 0.999) and diagnostic capability (0.905 vs 0.878, P = 0.669). Combined interpretation of WB-MRI and FDG-PET-CT showed no significant benefit over either technique alone. In conclusion, 3.0-Tesla WB-MRI is a feasible, non-ionising technique that showed similar diagnostic capacity to FDG-PET-CT in assessing distant-site status in patients with untreated NPC and can be recommended as the first-line imaging technique for comprehensive evaluation of such patients.

Amplatzer Septal Occluder Closure of Atrial Septal Defect: Evaluation of Transthoracic Echocardiography, Cardiac CT, and Transesophageal Echocardiography

OBJECTIVE The purpose of this study was to compare transthoracic echocardiography (TTE), cardiac CT, and transesophageal echocardiography (TEE) in the evaluation of secundum atrial septal defect (ASD) for closure with an Amplatzer septal occluder in pediatric patients. SUBJECTS AND METHODS The cases of 28 children with ASD initially diagnosed with TTE who were scheduled for cardiac CT for evaluation for insertion of an Amplatzer septal occluder under TEE guidance were reviewed. The patients were divided into a group with small ASD (long axis < 1.5 cm) and a group with large ASD (long axis > or = 1.5 cm). Measurements of the ASD obtained at TTE, cardiac CT, and TEE were compared. Kappa statistics were used to correlate the diagnostic value of cardiac CT assessed by two independent reviewers. RESULTS After cardiac CT, six patients were excluded from occluder implantation; therefore, 22 patients (seven boys, 15 girls; mean age, 4.95 years; range, 2-11 years) were included in the study. There were no significant differences in the ages and sexes of the patients in the two groups, but pulmonary-to-systemic blood flow ratio in the large-ASD group was significantly greater than that in the small-ASD group (3.54 +/- 1.43 vs 1.89 +/- 0.36; p = 0.001). With respect to long- and short-axis lengths of the ASD, interatrial septum, and four rims and to detection of rim deficiency, neither group had a significant difference between cardiac CT findings at ventricular end-systole and TEE findings. The long axis of the ASD in the large-ASD group measured at cardiac CT at end-systole and TEE was significantly longer than the long axis measured at TTE (p = 0.012). A high diagnostic score with good interobserver correlation (kappa = 0.674-0.750) validated the feasibility of cardiac CT in the assessment of ASD for closure with an Amplatzer septal occluder. CONCLUSION The long axis of a large ASD can be underestimated at TTE. Cardiac CT seems comparable with TEE in the assessment of ASD and is helpful in noninvasive evaluation for Amplatzer septal occluder implantation, especially for large ASD.

MDCT Angiography for Evaluation of the Complete Vascular Tree of Hemodialysis Fistulas

OBJECTIVE The purpose of our study was to assess the clinical feasibility of MDCT angiography for evaluating hemodialysis arteriovenous fistulas (AVFs). MATERIALS AND METHODS MDCT angiography of the complete vascular trees of 36 failing AVFs or AVF-related complications (20 native and 16 polytetrafluoroethylene graft AVFs) was reviewed. The numbers and degrees of stenoses at the anastomoses, graft loops, and draining and central veins and the presence of aneurysms or thrombosis were recorded. Wilcoxons signed rank test was used to compare the findings of MDCT angiography with those of digital subtraction angiography (DSA) (n = 10), surgery (n = 22), or both (n = 4) performed within 2-6 days. Kappa statistics were used to correlate the clinical feasibility of MDCT angiography assessed by two reviewers. RESULTS Among the 14 AVFs examined with both MDCT angiography and DSA, no significant difference was seen in the detection and grading (p = 0.317 to > 0.999) of stenoses at various segments of the entire vascular tree. Among the 36 AVFs examined, MDCT angiography also showed no significant difference from DSA or surgery in revealing vascular stenoses, aneurysms, and thromboses from the supplying artery to central veins (p = 0.317 to > 0.999). Overall, the sensitivity, specificity, positive and negative predictive values, and accuracy of MDCT angiography in lesion detection were 98.7%, 97.5%, 98.8%, 97.2%, and 98.3%, respectively. High image quality with superb interobserver correlation (kappa = 0.809 to > 0.999) validated the clinical feasibility of MDCT angiography for assessing AVFs. CONCLUSION MDCT angiography is clinically feasible for evaluating the complete vascular tree of failing AVFs and in showing uncommon complications, including brachial aneurysms and central vein lesions.

Transcatheter Arterial Embolization in the Emergency Department for Hemodynamic Instability Due to Ruptured Hepatocellular Carcinoma: Analysis of 167 Cases

OBJECTIVE The purpose of this study was to analyze the prognostic factors associated with emergency transcatheter arterial embolization in the treatment of patients in hemodynamically unstable condition caused by rupture of hepatocellular carcinoma. MATERIALS AND METHODS An 8-year retrospective cohort study was conducted to evaluate emergency transcatheter arterial embolization in the treatment of 167 patients in unstable hemodynamic condition (systolic blood pressure < 90 mm Hg at presentation) due to rupture of hepatocellular carcinoma. The clinical, laboratory, and imaging findings of a group who died (survival period, < or = 30 days) were compared with those of a group who survived more than 30 days. RESULTS On arrival in the emergency department, the group who died (n = 52) were in significantly worse condition than the group who survived (n = 115). The group who died had a poorer Child-Pugh class, lower hemoglobin and serum albumin levels, higher demand for blood transfusion, higher incidence of acute respiratory failure, worse neurologic status (Glasgow Coma Scale score, < or = 12), greater prevalence of portal vein thrombosis, and higher serum total bilirubin and creatinine levels (p < 0.05, two-sample Students t test and Fishers exact or chi-square test). Multivariate logistic regression analysis showed that patients who did not have portal venous thrombosis (odds ratio, 0.241; p = 0.012) or a lower creatinine level (odds ratio, 0.458; p = 0.003) had better probability of survival. Successful hemostasis with transcatheter arterial embolization was achieved in 99% of patients (30-day mortality rate, 31%). Patients with coexistent acute respiratory failure or impaired neurologic status and marked hyperbilirubinemia (> 2.7 mg/dL) had exceptionally high mortality rate (> 70%). CONCLUSION Emergency transcatheter arterial embolization is effective for hemostasis of ruptured hepatocellular carcinoma in patients in hemodynamically unstable condition being treated in the emergency department. However, patients with portal venous thrombosis, a high serum creatinine level, acute respiratory failure, impaired neurologic status, and a high serum total bilirubin level continue to be at high risk of death.

Epidermal Cysts in the Superficial Soft Tissue Sonographic Features With an Emphasis on the Pseudotestis Pattern

The purposes of this study were to report the sonographic features of superficial epidermal cysts with an emphasis on the characteristic pseudotestis appearance and to highlight the spectrum of ancillary findings.

Anomalous systemic arterialization to normal basal segments of the left lower lobe: helical CT and CTA findings.

Purpose The purpose of this work was to evaluate the helical CT and CT angiography (CTA) findings of anomalous systemic artery (ASA) to the basal segments of the left lower lobe (LLL). Method Three patients (two had hemoptysis, one was asymptomatic) with blotchy nodular density in the LLL revealed on chest radiographs underwent helical CT and CTA. Bronchoscopy was performed in two of these patients. Angiography and surgery were performed in one patient. Results All three patients demonstrated characteristic helical CT and CTA findings including 1) a sigmoid-shaped ASA originating from the lower descending thoracic aorta, with a distal bulbous configuration and four arterial branches supplying the basal segments of the LLL; 2) absence of an interlobar pulmonary artery or presence of a small artery lateral to the truncus basalis; 3) engorged vascular markings in the basal segments of the LLL; and 4) normal tracheobronchial tree and lung parenchyma. Conclusion The findings in the present three cases suggest that the use of invasive studies such as angiography or bronchoscopy may be obviated in the diagnosis of ASA to the LLL because diagnosis can be provided through a clear set of criteria on helical CT and CTA.

Gallbladder carcinoma manifesting as acute cholecystitis: Clinical and computed tomographic features

BACKGROUND Gallbladder carcinoma is uncommon and may manifest as acute cholecystitis. An accurate diagnosis is helpful for operative planning and this study attempted to explore the distinctive clinical and computed tomographic (CT) features for differentiating acute cholecystitis alone from that with contemporaneous gallbladder carcinoma. METHODS This 20-year, retrospective study evaluated the CT features of 26 patients with surgically proven gallbladder carcinoma with clinical presentations of acute cholecystitis (carcinoma group). Thirty elderly patients with surgically proven simple acute cholecystitis were enrolled as age-matched controls (cholecystitis group). The clinical, laboratory, and CT findings were compared between the 2 groups. RESULTS The carcinoma and cholecystitis groups showed no significant differences with respect to clinical symptoms (abdominal pain, fever, and jaundice), serum total bilirubin level, leukocyte count, percentage of segmented leukocytes, presence of gallstones, and CT features of pericholecystic stranding/fluid and focally increased enhancement of adjacent liver. Fifteen of the 26 (57.6%) patients in the carcinoma group exhibited diffuse gallbladder wall thickening on CT and the other 11 exhibited focal thickening or intraluminal masses. Beside female predominance, the patients in the carcinoma group had significantly higher serum aspartate/alanine aminotransferase and alkaline phosphatase levels, a thicker gallbladder wall, smaller volume, lower frequency of triple-layer gallbladder wall enhancement pattern, and a higher frequency of enlarged regional lymph nodes than those in the cholecystitis group. CONCLUSION For elderly patients, especially women, presenting with acute cholecystitis and abnormal liver function, CT demonstration of focal gallbladder wall thickening, intraluminal masses, small gallbladder with diffuse wall thickening, and enlarged regional lymph nodes are suggestive of concurrent gallbladder carcinoma. Triple-layer gallbladder wall enhancement is suggestive of simple acute cholecystitis.

31P MR Spectroscopic Assessment of Muscle in Patients with Myasthenia Gravis before and after Thymectomy: Initial Experience

PURPOSE To prospectively assess muscle metabolism in myasthenia gravis (MG) patients before and after thymectomy by using phosphorus 31 (31P) magnetic resonance (MR) spectroscopy. MATERIALS AND METHODS With institutional review board approval and informed consent, resting and dynamic (31)P MR spectroscopy were performed in 14 healthy volunteers (five men, nine women; mean age, 33 years; range, 23-48 years) and 16 MG patients (six men, 10 women; mean age, 37 years; range 18-50 years) before and after thymectomy. Patients were stratified into groups according to the modified Osserman classification: mild-MG group (classes I-IIA) and moderate-to-severe-MG group (classes IIB-IV). Variables compared among the three groups (Kruskal-Wallis test) included the inorganic phosphate (P(i))-adenosine triphosphate (ATP) (P(i)/ATP) ratio, phosphocreatine (PCr)-ATP (PCr/ATP) ratio, P(i)/PCr ratio, muscle pH at resting and at end-exercise ( 31)P MR spectroscopy, rate constant for PCr recovery (k(PCr)), and maximum oxidative capacity (V(max)). These variables were also compared in MG patients before and after thymectomy (Wilcoxon signed rank test). RESULTS There were no significant differences in resting P(i)/ATP, PCr/ATP, and P(i)/PCr ratios and resting muscle pH among the three groups (control group, 14; mild-MG group, nine; moderate-to-severe-MG group, seven). Comparison of the control group with the mild-MG group and comparison of the mild-MG group before thymectomy with the mild-MG group after thymectomy showed no significant differences in end-exercise P(i)/ATP, PCr/ATP, and P(i)/PCr ratios; end-exercise muscle pH; k(PCr); and V(max). Compared with the control and mild-MG groups, the moderate-to-severe-MG group had significantly higher end-exercise P(i)/ATP and P(i)/PCr ratios and significantly lower end-exercise muscle pH, k(PCr), and V(max) before thymectomy (P < or = .001), but these values showed significant restoration to normal after thymectomy (P = .018). CONCLUSION Mild-MG group patients have muscle oxidative metabolism similar to that of healthy control subjects, whereas moderate-to-severe-MG group patients have impaired V(max) during exercise and a noticeable shift to glycolytic metabolism, but these abnormalities are reversible after thymectomy.

Sudden cardiac arrest during computed tomography examination: clinical findings and "dense abdominal veins" on computed tomography.

We report imaging findings in five patients who had sudden cardiac arrest during contrast-enhanced computed tomography (CT). We observed strikingly dense abdominal veins, variable degrees of arterial enhancement, and poor abdominal visceral enhancement. Comparison with a control group of 30 patients revealed a statistically significant increase in mean enhancement of the abdominal veins (including the inferior vena cava, bilateral renal veins, and major tributaries of the hepatic vein) (Kruskal–Wallis test, P < 0.05). These patients lacked any clear cause of cardiac arrest, and the arrest may have been related to an adverse reaction to contrast medium. Despite resuscitation, two patients died and three convalesced. In summary, sudden cardiac arrest is characterized by “dense abdominal veins” on CT in the absence of the cardiac pump function. This effect was presumably the result of forced reflux and stagnation of contrast medium in the abdominal veins without any dilution with the circulating blood, leading to a markedly dense appearance of these venous structures.