Zones of increased perfusion (hot spots) on perfusion lung scans: correlation with pulmonary arteriograms

Perfusion lung scans are occasionally characterized by focal zones of apparent hyperperfusion ("hot spots"). To investigate the frequency and significance of this phenomenon, ventilation-perfusion lung scans and pulmonary arteriograms were reviewed in 72 patients who underwent both procedures for the evaluation of suspected pulmonary embolism. Hot spots were present in the scans of 13 patients and usually occupied less than one pulmonary segment. Most hot spots were detected within a region of atelectasis identified on chest radiographs (38%). A substantial number of the remaining hot spots were located in the lung adjacent to regions of embolus. In patients with massive embolus, hot spots actually represented normally preserved perfusion in the presence of globally reduced perfusion elsewhere.     

The implication of hot spots on bone scans within the irradiated field of breast cancer patients treated with mastectomy followed by radiotherapy

Objective  To analyze the implication of abnormal hot spots in the irradiated field of patients treated with mastectomy followed by radiotherapy for breast cancer. Methods  We reviewed 1842 consecutive bone scans performed on 292 patients treated with a modified radical mastectomy and followed by radiotherapy. If abnormal hot spots at the irradiated sites were detected in the bone scans, we evaluated further studies to determine whether bone metastases were present. Radiation was given using 4 or 6 MV X-rays at a dosage of 50.4 Gy during 5.5 weeks with a dosage per fraction of 1.8 Gy. The follow-up period was 25–136 months (median 57 months). Results  Sixty patients (20.6%) developed bone metastasis. Solitary rib metastases were identified in four patients; all were detected outside of the irradiated field. Of 232 patients who did not develop bone metastases, hot spots in the irradiated field were detected in 30 patients (12.9%). A simple rib facture at the site of a hot spot was demonstrated in four patients. The cumulative incidence of hot spots at 5 years was 12.9%. The cumulative incidence of hot spots was more common in postmenopausal women, patients who were less than 60 kg, patients who received adjuvant hormonal therapy and patients who had radiation that included the supraclavicular area. Conclusions  We confirmed that the hot spots within the irradiated fields might be benign, especially in patients who were postmenopause, had a low body weight, received adjuvant hormonal therapy and who had radiation that included the supraclavicular area.     

Clinical significance of solitary rib hot spots on bone scans in patients with extraskeletal cancer: correlation with other clinical manifestations

PURPOSE: Bone scans showing solitary hot spots in the ribs pose diagnostic problems in patients with proved extraskeletal cancers. The authors wanted to determine the importance of solitary rib lesions and their correlation with other clinical manifestations. MATERIALS AND METHODS: The study included 199 patients with solitary rib hot spots on their bone scans. The follow-up radiographic and scintigraphic images were reviewed to determine their origin. The correlation between the occurrence of a malignant rib lesion and clinical data were determined using Pearson chi-square tests. RESULTS: Ninety-three patients had an established cause of the rib hot spot. Eleven (11.8%) had a solitary malignant rib hot spot and 82 (88.2%) had a solitary benign rib hot spot. None of the hot spots at costochondral junctions were malignant. Of the 11 patients with proved metastatic rib hot spots, 1 of 11 (9.1%) had localized bone pain, 5 of 6 (83.3%) were concordant with primary tumors, 4 of 7 (57.1%) had elevated tumor markers, and 5 of 11 (45.5%) had concurrent extraskeletal metastases. For the 82 patients with benign rib hot spots, the figures were 2 of 82 (2.4%), 43 of 57 (75.4%), 26 of 69 (37.7%), and 19 of 82 (23.2%), respectively. Statistical analysis did not show a significant correlation between the incidence of metastases in solitary rib hot spots and clinical manifestations. CONCLUSIONS: Most solitary rib hot spots on bone scans were benign. The interpretation of a solitary hot spot in the ribs is difficult even with the help of these clinical manifestations. Follow-up bone scintigrams or radiographs are needed for further investigation of solitary rib hot spots.     

Frequency and etiology of solitary hot spots in the pelvis at whole-body positron emission tomography/computed tomography imaging

PurposeTo determine the frequency and etiology of a single hypermetabolic focus within the pelvis with no other areas of increased 18-fluorodeoxyglucose (FDG) uptake in the reminder of the whole body in an oncological population.Method and MaterialsWe retrospectively examined the first 700 whole-body PET/CT scans performed at our institution for baseline staging or follow-up of cancer and identified all patients with a solitary focus of increased FDG uptake in the pelvis. All available medical records and imaging findings in these patients were reviewed in order to determine the etiology of increased FDG uptake.ResultsEight (1.1%) of the 700 patients had a solitary hot spot in the pelvis at positron emission tomography (PET)/computed tomography (CT) imaging, consisting of seven of 380 women and one of 320 men. In the seven women, increased FDG uptake was due to physiological endometrial uptake (n=2), leiomyoma (n=1), corpus luteum cyst (n=1), physiological ovarian uptake (n=1), urinary leak (n=1), and nonspecific colitis (n=1). In the man, uptake was due to recurrent rectosigmoid adenocarcinoma. None of the 700 patients was found to have metastatic disease in the pelvis.ConclusionIsolated pelvic hot spots at PET/CT imaging in an oncological population are not common and usually benign; physiological endometrial or ovarian uptake is the single commonest cause.     

Periportal contrast enhancement on CT scans of the liver

Periportal contrast enhancement relative to adjacent liver and portal blood has been reported on CT scans in cases of schistosomiasis and hepatic Kaposi sarcoma in AIDS patients. We observed this phenomenon in 10 (8%) of 130 consecutive, contrast-enhanced, nondynamic CT examinations of the abdomen. Thus, the occurrence is more common and less specific than previously reported. Seven of the 10 patients in our series were receiving chemotherapy for malignant disease, and three had abdominal pain with no definitive diagnosis. In four of the 10 patients, corresponding areas of periportal low attenuation or radiolucency were observed on initial dynamically enhanced scans. Periportal enhancement may be related to late diffusion of contrast material into periportal areas that were initially radiolucent. Such diffusion may occur because of endothelial insult. Periportal contrast enhancement appears to be a nonspecific finding on nondynamic contrast-enhanced CT scans of the abdomen. Periportal enhancement is important to recognize because it can mimic the appearance of portal vein thrombosis and may also be used to differentiate intrahepatic biliary dilatation from periportal radiolucency.     

Gold storage in the liver: appearance on CT scans

The authors present one case in which high attenuation values in the liver parenchyma on computed tomographic scans were found in a patient who had been previously treated with colloidal gold for rheumatoid arthritis. Reticuloendothelial storage of gold was proved by biopsy.     

IMRT fluence map editing to control hot and cold spots

Manually editing intensity-modulated radiation therapy (IMRT) fluence maps effectively controls hot and cold spots that the IMRT optimization cannot control. Many times, re-optimizing does not reduce the hot spots or increase the cold spots. In fact, re-optimizing only places the hot and cold spots in different locations. Fluence-map editing provides manual control of dose delivery and provides the best treatment plan possible. Several IMRT treatments were planned using the Varian Eclipse planning system. We compare the effects on dose distributions between fluence-map editing and re-optimization, discuss techniques for fluence-map editing, and analyze differences between fluence editing on one beam vs. multiple beams. When editing a beam’s fluence map, it is essential to choose a beam that least affects dose to the tumor and critical structures. Editing fluence maps gives an advantage in treatment planning and provides controlled delivery of IMRT dose.     

IMRT fluence map editing to control hot and cold spots

Manually editing intensity-modulated radiation therapy (IMRT) fluence maps effectively controls hot and cold spots that the IMRT optimization cannot control. Many times, re-optimizing does not reduce the hot spots or increase the cold spots. In fact, re-optimizing only places the hot and cold spots in different locations. Fluence-map editing provides manual control of dose delivery and provides the best treatment plan possible. Several IMRT treatments were planned using the Varian Eclipse planning system. We compare the effects on dose distributions between fluence-map editing and re-optimization, discuss techniques for fluence-map editing, and analyze differences between fluence editing on one beam vs. multiple beams. When editing a beam’s fluence map, it is essential to choose a beam that least affects dose to the tumor and critical structures. Editing fluence maps gives an advantage in treatment planning and provides controlled delivery of IMRT dose.     

Focal liver masses: enhancement patterns on contrast-enhanced images--concordance of US scans with CT scans and MR images

PURPOSE: To assess prospectively the concordance of enhancement patterns of focal liver masses on contrast material-enhanced ultrasonographic (US) scans with patterns on contrast-enhanced computed tomographic (CT) scans or magnetic resonance (MR) images. MATERIALS AND METHODS: This study was approved by the institutional review board; patients gave informed consent. Contrast-enhanced US and contrast-enhanced CT or MR imaging were performed in 135 patients (62 men, 73 women; mean age, 51 years) with 144 confirmed liver masses. Masses included 49 hepatocellular carcinomas, 13 metastases, 30 hemangiomas, 41 lesions of focal nodular hyperplasia, and 11 others. Randomized image sets from each modality were shown independently to three blinded readers, who answered identical questions about enhancement of the lesion and liver in the arterial and portal venous phases and changes with time. Concordance for modalities was calculated from answers of readers and consensus answers between readers, with 95% confidence intervals (CIs). The kappa values were calculated for interreader agreement. RESULTS: Features of arterial phase enhancement showed concordance of more than 76% for modalities. The highest concordance of 92% (132 of 144), with 95% CI of 86% and 95% (kappa>0.84), was for the presence of peripheral pools and centripetal progression. Concordance in the portal venous phase was lower, with agreement for predominant enhancement of the lesion in 61% (86 of 142), with 95% CI of 52% and 68% (kappa>0.83). Portal venous phase washout occurred in 75% (106 of 142), with 95% CI of 67% and 81% (kappa>0.81). The majority of discordances were for malignancies for which only US depicted no sustained enhancement in the portal venous phase. CONCLUSION: US shows high concordance with CT or MR imaging, especially for the arterial phase. Discordance in the portal venous phase may reflect the tendency of CT and MR contrast agents, unlike microbubbles, to diffuse into interstitium.     

Thyroid carcinoma m solitary hot thyroid lesions on Tc-99m sodium pertechnetate scans

Sixteen patients with nonsuppressible solitary hot thyroid lesions (SHTL) identified on T3 suppression images using Tc-99m sodium pertechnetate were studied over a period of 5 years. Of the 16 patients, 7 (44%) had papillary adenocarcinoma (PAC) and 9 (56%) had follicular adenoma (FA). Of the 7 patients with PAC, 3 were toxic and 4 nontoxic. Of the 9 patients with FA, 2 were toxic and 7 nontoxic. The Tl-201 chloride thyroid scans were useful in locating SHTL and revealing extranodular thyroid tissue. The echography was sensitive to visualization of the nodule structures. However, there were no significant differences between the clinical findings, radionuclide images, and echograms between for PAC and FA. All patients with PAC were treated by partial thyroidectomy and there were neither regional nor distant metastasis in any of them. In conclusion, our study provided the following extremely interesting result: SHTL in the present series have a higher incidence of malignancy than previously reported autonomously functioning thyroid lesions (AFTL). Histological examination is necessary for the diagnosis and management of SHTL and surgical treatment should be considered.     

编辑通量图控制调强治疗计划的剂量冷热点

目的 研究手动编辑通量图控制调强治疗计划靶区内外剂量冷热点的优势。方法选择5例头颈肿瘤患者，回顾性比较二次优化和编辑通量图两种方法对控制靶区内外冷热点剂量分布的差别。结果与第1次优化得到的凋强治疗计划相比，第2次优化使靶区内外冷热点剂量分别增加0．5％、减少1．1％，而编辑通量图使靶区内外冷热点剂量分别增加1．0％、减少4．2％。结论 编辑通量图，特别是二次优化后剂量改善不明显的计划．对改善靶区内外冷热点剂量分布很有效．