Transarterial Embolization of Renal Arteriovenous Malformations: Treatment Outcomes According to Angiographic Classification.

PURPOSE: To assess the different adjunctive catheter techniques required to achieve complete occlusion of renal arteriovenous malformations (rAVMs) of different angioarchitectural types. MATERIALS AND METHODS: Overall, data on 18 patients with rAVM (Type 1, n = 7; Type 2, n = 2; Type 3, n = 9; mean age, 53.8 years) who underwent 25 procedures between 2011 and 2022 were reviewed. The clinical presentations, endovascular techniques, arteriovenous malformation (AVM) occlusion rate, adverse events (including the incidence of renal infarction), and clinical symptoms and outcomes (including recurrence/increase of AVM) were analyzed according to the Cho-Do angioarchitectural classification. Posttreatment renal infarction was classified as no infarction, small infarction (<12.5%), medium infarction (12.5%-25%), and large infarction (>25%) using contrast-enhanced computed tomography or magnetic resonance imaging. RESULTS: Hematuria and heart failure were presenting symptoms in 10 and 2 patients, respectively. The embolic materials used were as follows: Type 1 rAVM, coils alone or with n-butyl-2-cyanoacrylate (nBCA); Type 2 rAVM, nBCA alone or with coils; and Type 3 rAVMs, nBCA alone. Fourteen patients underwent adjunctive catheter techniques, including flow control with a balloon catheter and multiple microcatheter placement, alone or in combination. Immediate postprocedural angiography revealed complete occlusion in 15 patients (83%) and marked regression of rAVM in 3 (17%). Small asymptomatic renal infarctions were observed in 6 patients with Type 3 rAVMs without any decrease in renal function. No major adverse events were observed. All symptomatic patients experienced symptom resolution. Recurrence/increase of rAVM was not observed during the mean 32-month follow-up period (range, 2-120 months). CONCLUSIONS: Transarterial embolization using adjunctive catheter techniques according to angioarchitectural types can be an effective treatment for rAVMs.

Extranodal NK/T-cell lymphoma with localized relapse in bone marrow of lower leg detected using PET-CT.

Extranodal natural killer (NK)/T-cell lymphoma (ENKTL) is a rare subtype of non-Hodgkin lymphoma (NHL) with poor prognosis, particularly in relapsed or refractory patients. Thus, timely detection of relapse and appropriate disease management are crucial. We present two patients with ENKTL, wherein positron emission tomography-computed tomography (PET-CT) with total-body coverage after induction therapy, detected newly relapsed regions in the bone marrow of the lower leg prior to progression. Case 1: A 47-year-old woman with nasal obstruction, showing 18F-fluoro-deoxyglucose (FDG) uptake in the nasal cavity (Lugano stage IE). After induction therapy (RT-2/3 DeVIC), PET-CT revealed abnormal uptake only in the right fibula. Case 2: A 68-year-old man with a skin nodule/ulcer and an enlarged right inguinal lymph node was diagnosed with advanced ENKTL. A PET-CT scan revealed abnormal uptake in the subcutaneous mass of the right medial thigh, lymph nodes, and descending colon (Lugano stage IV). After induction therapy, PET-CT revealed new abnormal uptake only in the left tibia. In both patients, CT-guided biopsy confirmed ENKTL recurrence. Moreover, PET-CT with whole-body coverage was useful for the timely assessment of relapse and detection of asymptomatic bone involvement. This approach allowed for modifications to treatment strategies in certain patients.

Lung-Optimized Deep-Learning-Based Reconstruction for Ultralow-Dose CT.

RATIONALE AND OBJECTIVES: To evaluate the image properties of lung-specialized deep-learning-based reconstruction (DLR) and its applicability in ultralow-dose CT (ULDCT) relative to hybrid- (HIR) and model-based iterative-reconstructions (MBIR). MATERIALS AND METHODS: An anthropomorphic chest phantom was scanned on a 320-row scanner at 50-mA (low-dose-CT 1 [LDCT-1]), 25-mA (LDCT-2), and 10-mA (ULDCT). LDCT were reconstructed with HIR; ULDCT images were reconstructed with HIR (ULDCT-HIR), MBIR (ULDCT-MBIR), and DLR (ULDCT-DLR). Image noise and contrast-to-noise ratio (CNR) were quantified. With the LDCT images as reference standards, ULDCT image qualities were subjectively scored on a 5-point scale (1 = substantially inferior to LDCT-2, 3 = comparable to LDCT-2, 5 = comparable to LDCT-1). For task-based image quality analyses, a physical evaluation phantom was scanned at seven doses to achieve the noise levels equivalent to chest phantom; noise power spectrum (NPS) and task-based transfer function (TTF) were evaluated. Clinical ULDCT (10-mA) images obtained in 14 nonobese patients were reconstructed with HIR, MBIR, and DLR; the subjective acceptability was ranked. RESULTS: Image noise was lower and CNR was higher in ULDCT-DLR and ULDCT-MBIR than in LDCT-1, LDCT-2, and ULDCT-HIR (p < 0.01). The overall quality of ULDCT-DLR was higher than of ULDCT-HIR and ULDCT-MBIR (p < 0.01), and almost comparable with that of LDCT-2 (mean score: 3.4 ± 0.5). DLR yielded the highest NPS peak frequency and TTF50% for high-contrast object. In clinical ULDCT images, the subjective acceptability of DLR was higher than of HIR and MBIR (p < 0.01). CONCLUSION: DLR optimized for lung CT improves image quality and provides possible greater dose optimization opportunity than HIR and MBIR.

CT-guided percutaneous radiofrequency ablation for lung metastases from colorectal cancer.

BACKGROUND: Radiofrequency ablation (RFA) can be a minimally invasive therapeutic option in patients with lung metastasis from colorectal caner. We aimed to elucidate the safety and survival benefit of computed tomography (CT)-guided percutaneous RFA for lung metastasis from colorectal cancer. METHODS: A total 188 lesions were ablated in 43 patients from 2005 to 2017. The clinicopathological and survival data of patients were collected retrospectively. The short- and long-term outcomes and prognostic factors were analyzed. RESULTS: Eight patients (18.6%) had viable extrapulmonary metastasis at RFA treatment. The median number of treated lung tumors was 2, and the median maximum diameter was 12 mm. Complications, such as pneumothorax, pleural effusion and subcutaneous emphysema, occurred in 24 (55.8%) patients. Although chest tube drainage for pneumothorax was needed in 6 patients (14.0%), there were no mortalities. Repeated RFA for lung recurrence after primary RFA was performed in 14 patients (32.6%). In a median follow-up of 24.3 months, the median progression-free and overall survival (OS) were 6.8 months and 52.7 months, respectively. The presence of extrapulmonary metastasis and a maximum tumors size of > 15 mm were independently associated with a worse disease-free survival and OS. The OS of patients who underwent repeated RFA was significantly better than that of patients who underwent RFA only once. CONCLUSION: CT-guided percutaneous RFA for lung metastasis from colorectal cancer is a safe and effective procedure in patients not eligible for surgery, particularly for lesions smaller than 1.5 cm without extrapulmonary metastasis.

Pulmonary Mucosa-associated Lymphoid Tissue Lymphoma with Spontaneous Regression after Computed Tomography-guided Needle Biopsy: A Case Report and Summary of 8 Reported Cases.

A 72-year-old woman was admitted to our hospital with a solitary right lung nodule. She had no symptoms and no abnormal physical findings except for bladder cancer. Tumor markers were mildly elevated but no other abnormal laboratory data were found. The nodule was diagnosed to be pulmonary mucosa-associated lymphoid tissue lymphoma on computed tomography-guided needle biopsy. Thereafter, she first underwent surgery for bladder cancer. The lung nodule was found to have slightly increased at three months and then disappeared at 15 months after the biopsy. The notable clinical course of this rare disease suggests the effectiveness of a non-interventional treatment strategy.

Radiofrequency ablation for pulmonary metastases from gastrointestinal cancers.

The lung is one of the most common targets of metastases from gastrointestinal (GI) cancers. Surgical treatment (i.e., metastasectomy) is an accepted therapeutic option for pulmonary metastases from GI cancers. However, surgery may be contraindicated in advanced stages of cancer, compromised lung function, and/or comorbidities. This issue has prompted the search for innovative and less invasive ways of treating pulmonary metastases. Image-guided radiofrequency ablation (RFA) has attracted great interest as a minimally invasive approach against intrathoracic malignancies. In this technique, radiofrequency energy is applied via a needle electrode inserted into the target tissue. As the cells are agitated by the applied energy, they release heat, causing denaturation and cell death. Recently, this technique has been used on patients with pulmonary metastatic disease arising from GI cancers such as colorectal cancer, esophageal cancer, and hepatocellular carcinoma, as well as on patients with primary lung cancer. The present review updates the clinical outcomes and advances in RFA therapy of lung metastases from GI cancers.

Pain control in patients with hepatocellular carcinoma treated by percutaneous radiofrequency ablation: comparison of the efficacy of one-shot and continuous intravenous fentanyl delivery.

BACKGROUND: Hepatic percutaneous radiofrequency ablation (RFA) is usually performed with the patient under deep intravenous (i.v.) sedation or general anesthesia. Nonetheless, many patients report pain during and/or after the procedure. PURPOSE: To perform a prospective study of pain control obtained by the i.v. one-shot delivery and the continuous i.v. infusion of fentanyl in patients with hepatocellular carcinoma (HCC) treated by RFA. MATERIAL AND METHODS: Between April 2007 and March 2010, 83 patients with 106 HCCs underwent percutaneous RFA. All HCCs were addressed by computed tomography (CT)-guided percutaneous RFA performed within 5 h of embolization of the tumor vessels with iodized oil and gelatin sponges. Standard anesthesia consisted of 10 mL of 1% lidocaine injected locally. For conscious sedation, group one patients (n = 41) were injected i.v. with 100 µg of fentanyl before and 100 µg of fentanyl 30 min after percutaneous RFA. In group two (n = 42) we delivered fentanyl by continuous i.v. infusion at 100 µg/h during RFA. Upon request, patients in both groups also received 5 mg of diazepam i.v. for pain during the RFA procedure. The severity of pain experienced by all patients was evaluated on a visual analogue scale (VAS) and complications elicited by the anesthesia regimens were recorded. We also assessed the effectiveness of the treatment on sequential follow-up CT and/or magnetic resonance imaging (MRI) at 3-month intervals. RESULTS: Percutaneous RFA was technically successful in all 83 patients. Two patients in group one (4.8%) and one patient in group two (2.4%) manifested residual enhancement 3 months post RFA. There was no significant difference in the local recurrence rate between the two groups. At 4.0 ± 1.8 for group one and 3.4 ± 1.9 for group two, the VAS score was not significantly different. Major fentanyl or diazepam toxicity was recorded in 11 patients (24.4%) in group one and two patients (4.8%) in group two; the difference was statistically significant (P < 0.01). CONCLUSION: The continuous infusion of fentanyl provided effective and safe analgesia in HCC patients undergoing percutaneous RFA.

Comparison of CT-guided percutaneous biopsy with and without registration of prior PET/CT images to diagnose mediastinal tumors.

PURPOSE: To compare computed tomography (CT)-guided percutaneous biopsy with and without registration of prior positron emission tomography (PET)/CT images in the diagnosis of mediastinal tumors. METHODS: We performed clinically indicated percutaneous biopsy in 106 patients with mediastinal tumors in the anterior (n = 61), posterior (n = 21), middle (n = 16), and superior mediastinum (n = 8). The final diagnosis was based on surgical outcomes, or imaging findings and the results of at least 6-month follow-up. The patients underwent CT-guided percutaneous biopsy with (group 1, n = 56) or without (group 2, n = 50) registration of prior PET/CT images obtained no more than 22 days earlier. The registered images were used to plan the procedure and help target the tumors. RESULTS: CT-guided percutaneous needle biopsy yielded adequate samples in 101 of 106 (95 %) patients (group 1, n = 53; group 2, n = 48); in 95 patients (94 %), the diagnosis was confirmed by specific histological typing (group 1, n = 51; group 2, n = 44). The diagnostic accuracy of CT-guided percutaneous biopsy with and without the registration of prior PET/CT images was not statistically different (group 1, 96 %; group 2, 93 %, p = 0.324). CONCLUSION: CT-guided percutaneous biopsy is an easy and safe procedure that can provide a precise diagnosis in the majority of mediastinal tumors. PET/CT-guided biopsy yielded no special diagnostic advantages.

Radiofrequency ablation in a porcine kidney model: effect of occlusion of the arterial blood supply on ablation temperature, coagulation diameter, and histology.

BACKGROUND: Radiofrequency ablation (RFA) is susceptible to the cooling effect of flowing blood. The reduced efficacy of RFA in large tumors reflects the in vivo biophysiological limitations imposed by perfusion-mediated vascular cooling. PURPOSE: To compare the effects of RFA alone and of RFA combined with occlusion of the arterial blood supply on the tissue temperature, coagulation diameter, and histological changes in the acute phase. MATERIAL AND METHODS: The temperature at roll-off, the coagulated tissue diameter, and histologic tissue changes were compared in normal porcine kidneys subjected in situ to two pigs each were subjected to RFA alone (four kidneys) or to RFA plus balloon occlusion of the renal artery (four kidneys). The tissue temperature was measured at three sites: area I, the center of the RFA field; area II, the ischemic field 1 cm distant from the edge of the RFA field; and area III, the normal kidney. Tissue samples were stained with hematoxylin and eosin (H&E). Cell viability in the ablated zone was determined by nicotinamide adenine dinucleotide (NADH) staining of frozen sections. RESULTS: The tissue temperatures achieved by RFA in areas I, II, and III were 101°C, 58°C, and 40°C with and 92°C, 44°C, and 38°C without balloon occlusion, respectively. The maximal coagulation diameter was 31 mm with and 23 mm without occlusion. The coagulation diameter was significantly larger and the temperature in area II was significantly higher in kidneys subjected to RFA with renal artery occlusion. H&E staining showed preservation of the normal renal parenchymal structure outside the thermal lesion and an increase in eosinophilic cells with indistinct cell borders and nuclei within the thermal lesion. H&E and NADH staining demonstrated a sharp demarcation between the ablation and normal tissue area and showed that in area II the addition of balloon occlusion did not produce histologic changes different from those in kidneys subjected to RFA alone. CONCLUSION: A technique that combines RFA and partial renal artery occlusion may be useful in treatment of the non-resectable renal tumors with sizes appropriate for RF ablation.

Direct percutaneous embolization of an iatrogenic lumbar artery pseudoaneurysm following unsuccessful coil embolization.

A 56-year-old man with acute myeloleukemia was hospitalized for lumbar pain. Treatment with antibiotics failed to improve the symptoms. For the diagnosis of infiltration by leukemia we performed CT-guided percutaneous needle biopsy of the L2-L3 disc and the L3 vertebral body using a left posterolateral approach. His symptoms were improved by treatment with antibiotics and he was discharged 4 days later. He again experienced lumbar pain 4 days post-discharge and was readmitted. Unenhanced CT scans of the abdomen and pelvis revealed a giant hematoma in the left psoas muscle and we suspected lumbar arterial injury. A preoperative aortography and transcatheter arterial coil embolization was then performed for the diagnosis and treatment of a lumbar artery pseudoaneurysm. On the preoperative angiography, pseudoaneurysm arising from the left lumbar artery was shown. All feeders were shown by the selective catheterization of the lumbar arteries and they were completely embolized using coils. However, contrast-enhanced CT obtained on the next day still demonstrated a pseudoaneurysm in the left psoas muscle. Thus, additional percutaneous embolization using N-butyl-2-cyanoacrylate was performed. After this procedure, complete embolization of the pseudoaneurysm was obtained and his lumbar pain was relieved.

FDG-PET/CT-based gross tumor volume contouring for radiation therapy planning: an experimental phantom study.

As there is continuing controversy over the role of F-18-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT-fused imaging in radiation therapy (RT) planning, we performed a phantom study to assess the feasibility of FDG-PET/CT-based gross tumor volume (GTV) contouring. The phantom set, consisting of an elliptical bowl and 6 spheres measuring from 10-37 mm in diameter, were filled with FDG to obtain 3 source-to-background ratios (SBRs) of 4, 8, and 16. The ratio to maximum intensity at 5% intervals was applied as the threshold for contouring. The ratio between contoured- and actual volumes (volume ratio) was calculated, and the threshold ratio was selected to provide a volume ratio close to 100%. To consider the clinical application, we applied the threshold value (maximum intensity × threshold ratio) for the largest 37-mm sphere to the 6 spheres. The threshold ratio and the volume ratio in 6 spheres with 3 SBRs were compared using the Friedman test. Threshold ratios ranged from 25-80%; they were higher for smaller spheres (p = 0.003) and lower SBRs (p < 0.001). The volume ratios with the threshold value for the largest 37-mm sphere were lower in smaller spheres (p = 0.010). These results suggest that smaller lesions and higher background activities require a higher threshold ratio and smaller lesions a lower threshold value. FDG-PET/CT-fused imaging should not be used as a single modality but rather to obtain supplemental information in RT planning. The contoured GTV should be adjusted based on clinical data including conventional images.

Sequential combination treatment (arterial embolization and percutaneous radiofrequency ablation) of inoperable renal cell carcinoma: single-center pilot study.

BACKGROUND: Potential drawbacks of percutaneous radiofrequency ablation (RFA) for renal cell carcinoma (RCC) include local recurrence after RFA due to a limited ablation area, massive hemorrhage induced by kidney puncture, and difficulty in visualizing the tumor at CT-guided puncture. PURPOSE: To evaluate retrospectively the technical success, effectiveness, and complications elicited in patients with unresectable RCC following single-session sequential combination treatment consisting of renal arterial embolization followed by RFA. MATERIAL AND METHODS: Ten patients (12 RCCs) who were not candidates for surgery were included in this pilot study. All tumors ranged from 18-66 mm in size (mean 31 ± 3.9 mm), and were percutaneously ablated several hours after embolization of the tumor vessels with iodized oil and gelatin sponges. We evaluated the technical success, effectiveness, effect on renal function, and complications of this treatment. Effectiveness was judged on CT and/or MR images obtained every three months after RFA. The effect on renal function was assessed based on the creatinine level and glomerular filtration rate (GFR) before, one week, and three months after the procedure. RESULTS: Renal arterial embolization followed by percutaneous RFA was technically successful in all patients. On contrast CT and/or MR images obtained one week and three months after RFA we observed necrosis in the embolized segment of all RCCs. There were no major complications during and after the procedure. All patients reported tolerable pain and a burning sensation during RFA. After the procedure, five patients (50%) experienced back pain, one each manifested fluid collection, subcapsular hematomas, hematuria, or nausea. There were no instances of recurrence during a mean follow-up period of 47 ± 3.8 months. We noted no significant difference in serum creatinine and GFR before and after treatment. CONCLUSION: Our pilot study suggests that sequential combination treatment by renal arterial embolization followed by percutaneous RFA is feasible in patients with inoperable RCC. The treatment complications were acceptable and excellent effects were obtained.

[A case of recurrent esophageal cancer with lymph node and lung metastases, successfully treated with systemic chemotherapy and radiofrequency-ablation].

We report a case of recurrent esophageal cancer with lymph node and lung metastases, successfully treated with systemic chemotherapy and radiofrequency-ablation(RFA). A 45-year-old man was diagnosed with thoracic esophageal cancer.Radical esophagectomy with three-field lymphadenectomy was performed.After 6 months, mediastinal lymph node recurrence occurred.Although the size of the recurrent mediastinal lymph nodes were reduced after 10 courses of systemic chemotherapy, two new lung metastatic nodules appeared in the right segments 8 and 9.CT -guided percutaneous RFA was successfully achieved for the 2 lesions.However, 6 months after the RFA, a local recurrence at the RFA site of segment 9 occurred, and an additional RFA was performed for this tumor.Five years and four months after the first operation, the tumor marker level remained within a normal range, and the patient is doing very well without any signs of recurrence. RFA appears to be an effective and minimally invasive technique for controlling local recurrence of esophageal cancer when combined with systemic chemotherapy.

Percutaneous radiofrequency ablation for pulmonary metastases from hepatocellular carcinoma: results of a multicenter study in Japan.

PURPOSE: To retrospectively evaluate technical success, effectiveness, complications, patient survival, and prognostic factors with percutaneous radiofrequency (RF) ablation for pulmonary metastases resulting from hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Thirty-two patients from six institutions were included, with a total of 83 pulmonary metastases treated in 65 sessions. RF ablation was always performed percutaneously with computed tomography (CT) guidance. Primary endpoints were technical success and technique effectiveness. Technique effectiveness was evaluated based on sequential follow-up CT images. Secondary study endpoints were complications, patient survival, and determination of prognostic factors. Complications were classified as major or minor. Prognostic factors were determined by analyzing multiple variables with the log-rank test. RESULTS: Technical success rate was 100%. Primary technique effectiveness rates were 92% each at 1, 2, and 3 years. Major and minor complications occurred after 16 (25%) and 23 (35%) of the 65 sessions, respectively. The median follow-up period was 20.5 months. Overall survival rates were 87% at 1 year and 57% each at 2 and 3 years (median and mean survival times, 37.7 mo and 43.2 mo, respectively). Significantly better survival rates were obtained in cases of (i) no viable intrahepatic recurrence (P < .001), (ii) Child-Pugh class A disease (P < .001), (iii) absence of liver cirrhosis (P < .001), (iv) absence of hepatitis C virus infection (P = .006), and (v) α-fetoprotein level of 10 ng/mL or lower (P = .007) at the time of RF ablation. CONCLUSIONS: RF ablation appears effective, with an acceptable safety profile, in selected patients with pulmonary metastases resulting from HCC.

Volume-doubling time of pulmonary nodules with ground glass opacity at multidetector CT: Assessment with computer-aided three-dimensional volumetry.

RATIONALE AND OBJECTIVES: To investigate the volume-doubling time (VDT) of histologically proved pulmonary nodules showing ground glass opacity (GGO) at multidetector CT (MDCT) using computer-aided three-dimensional volumetry. MATERIALS AND METHODS: We retrospectively evaluated 47 GGO nodules (mixed n = 28, pure n = 19) that had been examined by thin-section helical CT more than once. They were histologically confirmed as atypical adenomatous hyperplasia (AAH, n = 13), bronchioloalveolar carcinoma (BAC, n = 22), and adenocarcinoma (AC, n = 12). Using computer-aided three-dimensional volumetry software, two radiologists independently performed volumetry of GGO nodules and calculated the VDT using data acquired from the initial and final CT study. We compared VDT among the three pathologies and also compared the VDT of mixed and pure GGO nodules. RESULTS: The mean VDT of all GGO nodules was 486.4 ± 368.6 days (range 89.0-1583.0 days). The mean VDT for AAH, BAC, and AC was 859.2 ± 428.9, 421.2 ± 228.4, and 202.1 ± 84.3 days, respectively; there were statistically significant differences for all comparative combinations of AAH, BAC, and AC (Steel-Dwass test, P < .01). The mean VDT for pure and mixed GGO nodules was 628.5 ± 404.2 and 276.9 ± 155.9 days, respectively; it was significantly shorter for mixed than pure GGO nodules (Mann-Whitney U-test, P < .01). CONCLUSION: The evaluation of VDT using computer-aided volumetry may be helpful in assessing the histological entities of GGO nodules.

Effects of dual-energy subtraction chest radiography on detection of small pulmonary nodules with varying attenuation: receiver operating characteristic analysis using a phantom study.

PURPOSE: The aim of this study was to investigate the detectability of simulated pulmonary nodules with different X-ray attenuation by flat-panel detector (FPD) chest radiography using a dual-exposure dual-energy subtraction (DES) technique. MATERIALS AND METHODS: Using a FPD radiography system, we obtained 108 sets of chest radiographs of a chest phantom. They consisted of 54 sets each of chest radiographs with and without simulated nodules. Each data set contained a standard and a corresponding dual-energy subtracted chest radiograph (DES image). The diameters of the simulated nodules were 8, 10, and 12 mm, respectively; nodules of each size manifested attenuation of -450, -200, and 30 Hounsfield units (HU). We performed receiver operating characteristic (ROC) analysis to compare the observers' performance in detecting nodules. RESULTS: For the -450 HU nodules the mean areas under the ROC curve (AUC) without and with DES images were 0.66 and 0.77, respectively; the difference was significant (paired t-test, P < 0.01). For nodules with -200 and 30 HU, there was no significant difference in the AUC value (0.79 vs. 0.77, P = 0.13; 0.92 vs. 0.94, P = 0.17, respectively). CONCLUSION: The addition of DES images to standard chest radiographs improved the performance of radiologists charged with detecting simulated nodules with an attenuation of -450 HU.

Estimation of 123I-IMP arterial blood activity from dynamic planar imaging of the chest using a graph plot method for the quantification of regional cerebral blood flow.

PURPOSE: I-123-labeled N-isopropyl-p-iodoamphetamine ((123)I-IMP) is used for the measurement of regional cerebral blood flow (rCBF). A continuous or single arterial blood sampling (ABS) is necessary to estimate an integral of arterial input function (AIF) for the measurement of rCBF by using a microsphere model analysis. Therefore, a method of measuring rCBF without any blood sampling is desired. The aim of this study was to establish a method to estimate the AIF from the time-activity curve of the lungs after an injection of (123)I-IMP, using a regression analysis for the measurement of rCBF without any blood sampling. MATERIALS AND METHODS: Thirty-seven prospective studies in 10 consecutive patients were enrolled. A chest planar dynamic imaging for 3 min and continuous ABS for 5 min after a bolus injection of 167MBq (123)I-IMP were performed in all studies. Data from the chest imaging were analyzed in comparison with ABS data (AIF(5)) in the first 10 studies, and an equation for estimation yielding accurate AIF(5) from the total counts cleared from the lungs, during 5 min after injection of (123)I-IMP (TCL(5)), was derived. The validity of the proposed method was evaluated in the subsequent 27 studies. RESULTS: A good correlation was obtained between the AIF and TCL by regression analysis in the first 10 studies (r = 0.94, P < 0.001). An equation for the estimation of AIF by the regression analysis in the first 10 studies was defined as follows: estimated AIF = 2147 + 4.174 x TCL(5). In the subsequent 27 studies, a good linear correlation was obtained between the measured and the estimated AIF(5) by using the equation (r = 0.79, P < 0.001). CONCLUSION: AIF(5) can be accurately estimated from TCL(5). Therefore, estimated AIF(5) can be used for the measurement of rCBF instead of ABS data.

Computer-aided volumetry of pulmonary nodules exhibiting ground-glass opacity at MDCT.

OBJECTIVE: The purpose of this study was to investigate the accuracy and reproducibility of results acquired with computer-aided volumetry software during MDCT of pulmonary nodules exhibiting ground-glass opacity. MATERIALS AND METHODS: To evaluate the accuracy of computer-aided volumetry software, we performed thin-section helical CT of a chest phantom that included simulated 3-, 5-, 8-, 10-, and 12-mm-diameter ground-glass opacity nodules with attenuation of -800, -630, and -450 HU. Three radiologists measured the volume of the nodules and calculated the relative volume measurement error, which was defined as follows: (measured nodule volume minus assumed nodule volume / assumed nodule volume) x 100. Two radiologists performed two independent measurements of 59 nodules in humans. Intraobserver and interobserver agreement was evaluated with Bland-Altman methods. RESULTS: The relative volume measurement error for simulated ground-glass opacity nodules measuring 3 mm ranged from 51.1% to 85.2% and for nodules measuring 5 mm or more in diameter ranged from -4.1% to 7.1%. In the clinical study, for intraobserver agreement, the 95% limits of agreement were -14.9% and -13.7% and -16.6% to 15.7% for observers A and B. For interobserver agreement, these values were -16.3% to 23.7% for nodules 8 mm in diameter or larger. CONCLUSION: With computer-aided volumetry of ground-glass opacity nodules, the relative volume measurement error was small for nodules 5 mm in diameter or larger. Intraobserver and interobserver agreement was relatively high for nodules 8 mm in diameter or larger.

Diaphragm perforation after radio-frequency ablation for metastatic lung cancer.

A case of diaphragm perforation after radio-frequency ablation (RFA) for lung metastasis from uterine cervical cancer is reported. The patient developed pelvic recurrence and solitary lung metastasis after a radical hysterectomy for uterine cervical cancer. Pelvic radiation and RFA for lung metastasis were performed. Metastasis was located in the laterobasal segment of the lower lobe of the right lung. RFA was repeatedly performed in September 2005 and August 2006. In May 2008, ¹8F-fluoro-deoxy-glucose (FDG) positron emission tomography-computed tomography showed evidence of local recurrence of the lung metastasis. A solid lesion with FDG accumulation accompanying a cystic lesion was observed in the lung base. The patient underwent a wedge resection of the lung in June 2008, during which a perforated area of the diaphragm (3 cm in diameter) was identified under the cystic lesion, which was not herniated. The perforation in the diaphragm was closed with a simple continuous suture.

Difference of sentinel lymph node identification between tin colloid and phytate in patients with non-small cell lung cancer.

BACKGROUND: The advantages and disadvantages of technetium Tc 99m tin colloid and technetium Tc 99m phytate as tracers for sentinel node (SN) identification in patients with clinical stage I non-small cell lung cancer were examined retrospectively. METHODS: Sentinel node identification was conducted using tin colloid and phytate, respectively, in 73 and 74 patients with clinical stage I non-small cell lung cancer. We compared these two tracers in terms of identification rates, numbers of SNs, characteristics of patients whose SNs could not be identified, and the pathologic results of SNs. RESULTS: The tin colloid tracer identified SNs in 54 of the 73 patients (74%), which was significantly lower than the 89% (66 of 74 patients) in the phytate group (p = 0.02). The number of SNs per patient was 1.7 +/- 0.8 in the tin colloid group, which was significantly less than the 2.4 +/- 1.5 in the phytate group (p = 0.002). Although patients in the tin colloid group whose SNs could not be identified had a significantly lower forced expiratory volume in 1 second to forced vital capacity ratio than those whose SNs could be identified (p = 0.04), the phytate group did not show such a difference. Eleven of 120 patients whose SNs could be identified had pathologic N1 or N2 disease, but neither group showed any false-negative results for SN identification. CONCLUSIONS: Both tin colloid and phytate are reliable tracers for identifying SNs in non-small cell lung cancer. The advantage of phytate is that SNs can be detected more frequently than with tin colloid, even in patients with a low forced expiratory volume in 1 second to forced vital capacity ratio. However, tin colloid requires fewer nodes than phytate to identify SNs.