(18)F-Fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) for the early detection of response to neoadjuvant chemotherapy for locally advanced rectal cancer.

PURPOSE: Early detection of a response to neoadjuvant chemotherapy for locally advanced rectal cancer may spare patients from additional toxic but ineffective chemotherapy. Using (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET), we evaluated tumor response prospectively in the early course of preoperative chemotherapy. METHODS: The subjects were 15 patients who received neoadjuvant chemotherapy (XELOX or XELOX plus bevacizumab) for locally advanced rectal cancer. Patients underwent (18)F-FDG PET before chemotherapy, at the end of the first cycle of chemotherapy, and before surgical resection. Magnetic resonance imaging (MRI) was performed before chemotherapy, after the second cycle of chemotherapy, and before resection. After resection, the SUVmax and diameter were compared and graded according to the tumor regression grade (TRG). RESULTS: The TRG was assessed as TRG1 in one patient, TRG2 in five patients, and TRG3 in nine patients. We divided the patients into two groups: non-responders (NR) included the TRG1 and TRG2 patients, and responders (R) included the TRG3 patients. The tumor size before surgery was significantly smaller in the R group than in the NR group. The SUVmax at the end of the first cycle of chemotherapy and before surgical resection was significantly lower in the R group than in the NR group. CONCLUSION: Performing (18)F-FDG PET at the end of the first cycle of chemotherapy allowed us to predict the pathological response of locally advanced rectal cancer.

Early pharmacodynamic assessment using ¹8F-fluorodeoxyglucose positron-emission tomography on molecular targeted therapy and cytotoxic chemotherapy for clinical outcome prediction.

Early prediction of therapeutic outcome is important in determining whether the ongoing therapy is beneficial. In addition to anatomical response determined using the Response Evaluation Criteria in Solid Tumors (RECIST) criteria, recent studies have indicated that change in tumor glucose use on or after treatment correlates with histopathologic tumor regression and patient outcomes. This Perspective discusses the use of (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) for pharmacodynamic evaluation in a very early phase of treatment to predict clinical outcomes in patients with advanced non-small-cell lung cancer. We conducted a study to assess whether early metabolic response determined using FDG-PET correlated with clinical outcomes in patients treated with gefitinib or those treated with carboplatin plus paclitaxel (CP). Early metabolic response to gefitinib, but not CP, correlated with the late metabolic response, anatomical response, progression-free survival, and even overall survival. A rapid effect of molecular targeted agents might not be aptly evaluated using the conventional criteria, eg, RECIST, in a very early phase of treatment before volumetric shrinkage of the tumor. Based on the findings of several studies, and on the findings from our study, use of FDG-PET might enable prediction of clinical outcomes at a very early stage of treatment, especially in patients treated with molecular targeted agents with rapid clinical efficacy.

Ivy signs on FLAIR images before and after STA-MCA anastomosis in patients with Moyamoya disease.

BACKGROUND: Leptomeningeal high signal intensity (ivy sign) on fluid-attenuated inversion-recovery (FLAIR) MR imaging is one of the features of Moyamoya disease. However, the correlation between ivy sign and cerebral perfusion status has not been fully evaluated. PURPOSE: To characterize ivy sign on FLAIR images in Moyamoya disease and compare this finding with hemodynamic alterations on perfusion single-photon emission CT (SPECT) obtained before and after bypass surgery. MATERIAL AND METHODS: Sixteen patients with angiographically confirmed Moyamoya disease who underwent superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis were included in the study. The presence of ivy sign on FLAIR images was classified as 'negative', 'minimal' and 'positive'. We evaluated the relationship between ivy sign and findings of SPECT, including cerebral vascular reserve (CVR) before and after surgery. RESULTS: Minimal or positive ivy sign was seen in 13 (81%) of 16 patients, and 21 (66%) of 32 hemispheres. CVR in the areas with positive or minimal ivy sign was lower than that in the areas with negative ivy sign. After STA-MCA anastomosis, ivy sign disappeared or decreased in all 21 hemispheres demonstrating ivy sign. SPECT demonstrated apparent hemodynamic improvement in areas demonstrating disappearance or decrease of ivy sign. CONCLUSION: Ivy sign on FLAIR image is seen in areas with decreased cerebral perfusion. The sign is useful for non-invasive assessment of cerebral hemodynamic status before and after surgery.

Imaging appearances and management of isolated spontaneous dissection of the superior mesenteric artery.

OBJECTIVE: The objective of our study was to report the clinical and imaging features of isolated dissection of the superior mesenteric artery (SMA) and describe our imaging classification of this disease entity. SUBJECTS AND METHODS: We retrospectively analyzed clinical presentation, imaging appearances and outcome of the 12 patients who were diagnosed as having spontaneous dissection of the SMA from 1991 to 2005 in our institution or its affiliated two hospitals. There were 11 males and 1 female with a mean age of 50 years (range, 43-61 years). The diagnosis of isolated dissection was established with CT within 24h of the onset. RESULTS: We categorized SMA dissection into the following four types based on imaging appearances: type I, patent false lumen with both entry and re-entry (four patients), type II, 'cul-de-sac' shaped false lumen without re-entry (one patient), type III, thrombosed false lumen with ulcer like projection (ULP), which is defined as a localized blood-filled pouch protruding from the true lumen into the thrombosed false lumen (five patients) and type IV, completely thrombosed false lumen without ULP (two patients). One patient with type II underwent urgent surgery because of small bowel ischemia. One patient with type III underwent urgent embolotherapy for the treatment of rupture of a branch of the SMA. The remaining 10 patients were initially managed conservatively. In one of the conservatively treated patient, ULP had progressively dilated, and it was treated with stent placement and coil packing 22 months after the onset. The remaining nine patients were conservatively managed without any event during the follow-up period of 7-72 months. CONCLUSION: Most of the patients with isolated SMA dissection can initially be managed conservatively if there are no clinical and imaging signs indicating ruptured SMA branches or bowel ischemia.

Cancer screening with whole-body PET/CT for healthy asymptomatic people in Japan: re-evaluation of its test validity and radiation exposure.

The use of Positron Emission Tomography (PET) or PET/CT for voluntary cancer screening of asymptomatic individuals is becoming common in Japan, though the utility of such screening is still controversial. This study estimated the general test validity and effective radiation dose for PET/CT cancer screening of healthy Japanese people by evaluating four standard indices (sensitivity, specificity, positive/negative predictive values), and predictive values with including prevalence for published literature and simulation-based Japanese data. CT and FDG-related dosage data were gathered from the literature and then extrapolated to the scan parameters at a model PET center. We estimated that the positive predictive value was only 3.3% in the use of PET/CT for voluntary cancer screening of asymptomatic Japanese individuals aged 50-59 years old, whose average cancer prevalence was 0.5%. The total effective radiation dose of a single whole-body PET/CT scan was estimated to be 6.34 to 9.48 mSv for the average Japanese individual, at 60 kg body weight. With PET/CT cancer screening in Japan, many healthy volunteers screened as false positive are exposed to at least 6.34 mSv without getting any real benefit. More evaluation concerning the justification of applying PET/CT for healthy people is necessary.

Pediatric CT scan usage in Japan: results of a hospital survey.

PURPOSE: The aim of this study was to examine the usage parameters of diagnostic computed tomography (CT) in children because of concerns of possible overuse in Japanese hospitals, including the "technical" CT exposure settings and the "clinical" grounds for CT requests. MATERIALS AND METHODS: We examined the methodology at the radiology department to reduce radiation exposure to children and performed a retrospective study on pediatric CT requests during a 1-year period at Nagasaki University Hospital. The parameters of diagnostic CT usage for minor head trauma and acute appendicitis were studied in detail. RESULTS: CT radiation dose settings are adjusted for children based on guidelines issued by the Japan Radiological Society, with few limitations. CT requests were made for 62% of minor head trauma cases and 76% of cases clinically suspected to be acute appendicitis. These figures are considerably higher than those reported by studies in the United Kingdom, Canada, or the United States. No specific guidelines are advocated regarding CT usage for minor head trauma. The diagnosis of acute appendicitis in children is almost routinely referred for "confirmation" by CT. CONCLUSION: CT radiation risks to children at Japanese hospitals need to be considered more seriously. Physicians should be encouraged to follow diagnostic algorithms that help avoid unnecessary CT usage in children.

Quantification of the regional cerebral blood flow and vascular reserve in moyamoya disease using split-dose iodoamphetamine I 123 single-photon emission computed tomography.

OBJECTIVES: We quantified the rCBF and regional vascular reserve (CVR) in adult patients with moyamoya disease before and after surgery using IMP I 123 SPECT. METHODS: The patient population included 5 adult patients with ages at presentation ranging between 23 and 42 years. One patient had stroke, whereas 4 patients had transient ischemic attacks. RESULTS: Before surgery, the mean resting rCBF and mean CVR in the frontal, parietal, and temporal lobes of the surgically treated hemisphere were 40.09, 39.50, and 36.9 mL/100 g per minute and 15.39%, 27.09%, and 28.92%, respectively. After surgery, the rCBF increased significantly (P = .0002, .0005, and .0062), but in a CVR evaluation, only the frontal lobe increased significantly (P = .0055). In the unaffected hemispheres, the mean resting rCBF significantly increased only in the frontal lobe (P = 038) and no significant increase in the CVR was observed after surgery. In 2 patients who showed steal phenomenon induced by acetazolamide administration, CVR significantly increased not only in the frontal lobe but also in the parietal and temporal lobe after surgery, although the CVR in these areas significantly decreased both before and after surgery in comparison to the mean CVR in all patients. CONCLUSIONS: The frontal lobe showed severe hemodynamic ischemia. The cerebral hemodynamics in patients with moyamoya disease improved after surgical intervention, especially in severely damaged patients. Split-dose (123)I-IMP SPECT was therefore found to be a useful diagnostic modality for quantifying the hemodynamics of moyamoya disease.

Dramatic improvement in Down syndrome-associated cognitive impairment with donepezil.

OBJECTIVE: To report 2 cases of patients with Down syndrome and severe cognitive impairment who gained dramatic improvements in quality of life (QOL) upon donepezil treatment. CASE SUMMARIES: Case 1. A 38-year-old woman with Down syndrome, diagnosed with secondary progressive dementia when her mental state had deteriorated rapidly after graduation from junior high school, started donepezil treatment. The loading dose was 3 mg/day and was increased to 5 mg/day for maintenance. One month after the dose was increased, adverse effects such as soft stool and urinary incontinence appeared. These adverse effects disappeared when the dose was decreased again to 3 mg/day. Her QOL improved dramatically with this minimal dose. She recovered verbal and written communication skills that she had lost for the past 21 years. Case 2. A 22-year-old man with Down syndrome, who had been diagnosed as having severe mental retardation, was put on donepezil therapy. Both loading and maintenance doses were 3 mg/day. His QOL had also dramatically improved, with some recovery in verbal communication. Transient agitation/violence and transient muscle weakness appeared during the first few months of treatment. DISCUSSION: Patients with Down syndrome may be more sensitive to donepezil therapy than others and may benefit from this medicine, although they may also have adverse effects more frequently. CONCLUSIONS: Donepezil may be a useful medicine for some patients with Down syndrome with severe cognitive impairment or mental retardation if the adverse effects are manageable.