The true axial shoulder projection: Diagnostic aid for acromioclavicular joint dislocation?

INTRODUCTION

Acromioclavicular joint dislocations are common. Differentiating between horizontal and vertical instability is challenging, but possible to diagnose on axial radiographs. No clear consensus for axial radiograph parameters currently exists. We aim to establish a reproducible technique to assess whether an axial radiograph represents a true axial view of the shoulder.

METHODS

One hundred CT scans of normal uninjured shoulders were examined using multiplanar reformatting to assess the distance between the anterior glenoid (reference line) and anterior-most aspect of the acromion in the axial plane. Measurements were repeated and performed by multiple observers to give of intra- and inter-observer reliability.

RESULTS

The mean distance from the anterior acromion to the reference line was -2.6 mm (i.e. posteriorly placed) (SD = 5.8 mm, range -16.9-13.2 mm). Most (89%) of the measurements were between 9 and -9 mm to the reference line. Intra-observer reliability was high with Cronbach's α measurement as 0.997. Inter-observer reliability gave a Cronbach's α measurement of 0.959.

CONCLUSION

When the anterior aspect of the acromion lies within 10 mm either side of a line parallel to the scapula blade at the anterior aspect of the glenoid on an axial radiograph, it represents a true axial projection of the glenohumeral joint (GHJ).Level of evidence: IV, Case series.

A Dataset for Three-Dimensional Distribution of 39 Elements Including Plant Nutrients and Other Metals and Metalloids in the Soils of a Forested Headwater Catchment

Quantification and evaluation of elemental distribution in forested ecosystems are key requirements to understand element fluxes and their relationship with hydrological and biogeochemical processes in the system. However, datasets supporting such a study on the catchment scale are still limited. Here we provide a dataset comprising spatially highly resolved distributions of 39 elements in soil profiles of a small forested headwater catchment in western Germany () to gain a holistic picture of the state and fluxes of elements in the catchment. The elements include both plant nutrients and other metals and metalloids that were predominately derived from lithospheric or anthropogenic inputs, thereby allowing us to not only capture the nutrient status of the catchment but to also estimate the functional development of the ecosystem. Soil samples were collected at high lateral resolution (≤60 m), and element concentrations were determined vertically for four soil horizons (L/Of, Oh, A, B). From this, a three-dimensional view of the distribution of these elements could be established with high spatial resolution on the catchment scale in a temperate natural forested ecosystem. The dataset can be combined with other datasets and studies of the TERENO (Terrestrial Environmental Observatories) Data Discovery Portal () to reveal elemental fluxes, establish relations between elements and other soil properties, and/or as input for modeling elemental cycling in temperate forested ecosystems.

Future imaging techniques in aortic pathologies and clinical implications

Future imaging techniques in aortic pathology will be used to detect early subclinical pathological changes and to identify patients who would benefit from early surgical intervention. Current imaging for aortic pathology is mainly computed tomography (CT). This modality produces static images which are used as the basis to decide which patients require intervention. Subclinical disease can be detected experimentally by novel magnetic resonance (MR) techniques such as molecular imaging: measurement of the amount of elastin in the aortic wall has the potential to identify patients with low levels of elastin at risk of aortic dilatation. These patients could then be monitored in a more intensive aneurysm surveillance programme. Endothelial dysfunction can also be detected experimentally by MR techniques. Measurement of endothelial permeability will be used to tailor preventative medical treatment to individual patients. Aortic diameter is the main indication for treatment in both aortic aneurysms and chronic aortic dissection but may be prone to error. False lumen thrombosis detected on first-pass imaging is used as an outcome measure in randomized controlled trials. Blood pool contrast agent imaging is flow independent and is not subject to the significant error associated with current imaging methods. Four-dimensional phase contrast magnetic resonance (4D PC-MR) imaging can quantify flow in both the true and false lumens of aortic dissection. The amount and pattern of flow in the false lumen is related to the rate of aortic expansion. 4D PC-MR can demonstrate entry tears between the true and false lumens and this information can be used to guide endovascular treatment. Hybrid imaging techniques such as positron emission tomography (PET) combined with CT (PET-CT) can give information about the degree of inflammation in the aortic wall, and preliminary studies have shown that a positive scan can predict patients with dissection who are likely to have a poor outcome. These new techniques combine anatomical and functional data in a single acquisition. The richness of the data allows a greater understanding of the pathophysiology in each individual patient which will result in improved clinical outcomes.

Resected pancreatic neuroendocrine tumors: Patterns of failure and disease-related outcomes with or without radiotherapy

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Background: Pancreatic neuroendocrine tumors (NET) are rare with improved prognosis compared to adenocarcinomas. Surgical resection remains the standard of care although many patients present with unresectable/metastatic disease. While many resected patients will fail distantly, little is known regarding the use of adjuvant radiotherapy. To define this and establish specific patterns of failure, an analysis of resected patients from a single institution was performed.

Methods: From 1994 to 2009, 33 patients with NET of the pancreatic head underwent resection with curative intent at Duke University. Sixteen patients were treated with surgical resection alone, and an additional 17 underwent resection with adjuvant (n=10) or neoadjuvant (n=7) radiation therapy, usually with concurrent fluoropyrimidine-based chemotherapy (CMT). Median radiation dose was 50.4 Gy and median follow-up 28 months.

Results: Patients receiving radiation therapy were more likely to have involved nodes (47% vs 19%, p=0.09), more mitoses per high power field (p=0.10) and involved margins (47% vs 31%, p=0.20) compared to surgery alone patients. Median survival for the whole cohort was 52 months. Two-year survival was 68% for the CMT group and 93% for the surgery alone group (p=0.03). Two-year local control was 85% for the CMT and 90% for the surgery group (p=0.49). Two-year metastasis-free survival was 45% and 69% for the CMT and surgery patients, respectively (p=0.02).

Conclusions: Patients receiving CMT were more likely to have adverse pathologic features compared to surgery-alone patients. Survival outcomes were high in both groups, although less so in the CMT group. Distant metastasis development dominated patterns of failure. Local failure following resection of NETs is uncommon, and the role of adjuvant radiotherapy in this setting remains unclear.

No significant financial relationships to disclose.

Impact of positive pleural lavage cytology on survival in patients undergoing lung resection for non-small cell lung cancer: An international multicenter study

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Background: Pleural lavage cytology (PLC) is the instillation of saline into the chest during surgery for non-small cell lung cancer (NSCLC). The aims of this study were to collate multi-institutional individual patient data to determine independence as a prognostic marker and characterise impact of positive results on stage adjusted survival. Methods: We identified 31 publications from 22 centers/research groups that performed pleural lavage cytology during surgery for NSCLC and invited submission of individual patient data. Actuarial survival was calculated using Kaplan Meier methods and comparisons were performed using the log-rank test. Cox proportional hazards regression was utilised to ascertain the covariates associated with survival. Results: By 1 January 2008, submissions were received internationally from 11 centers with individual data from 8763 patients. In total, 511 (5.8%) patients had a positive pleural lavage cytology result, and this was shown to be an independent predictor of adverse survival associated with a hazard ratio of 1.465 (1.290 - 1.665; P<0.001). On statistical modelling, the best adjustment for patients with a positive PLC result was a single increase in the T category assigned to the case, up to a maximum of T4. Correction for differences in survival were obtained in stage IB (P=0.315) and IIB (P=0.453), with a degree of correction in stage IIIA (P=0.07). Conclusions: Pleural lavage cytology should be considered in all patients with NSCLC suitable for resection. A positive result is an independent predictor of adverse survival and the impact on survival suggests that it may be appropriate to upstage patients by one T category.

No significant financial relationships to disclose.

Timing and patterns of recurrences and deaths from prostate cancer following adjuvant pelvic radiotherapy for pathologic stage T3/4 adenocarcinoma of the prostate

To determine the timing and patterns of late recurrence after radical prostatectomy (RP) alone or RP plus adjuvant radiotherapy (RT). Between 1970 and 1983, 159 patients underwent RP for newly diagnosed adenocarcinoma of the prostate and were found to have positive surgical margins, extracapsular extension and/or seminal vesicle invasion. Of these, 46 received adjuvant RT and 113 did not. The RT group generally received 45-50 Gy to the whole pelvis, then a boost to the prostate bed (total dose of 55-65 Gy). In the RP group, 62% received neoadjuvant/adjuvant androgen deprivation vs 17% in the RT group. Patients were analyzed with respect to timing and patterns of failure. Only one patient was lost to follow-up. The median follow-up for surviving patients was nearly 20 years. The median time to failure in the surgery group was 7.5 vs 14.7 years in the RT group (P=0.1). Late recurrences were less common in the surgery group than the RT group (9 and 1% at 10 and 15 years, respectively vs 17 and 9%). In contrast to recurrences, nearly half of deaths from prostate cancer occurred more than 10 years after treatment. Deaths from prostate cancer represented 55% of all deaths in these patients. Recurrences beyond 10 years after RP in this group of patients were relatively uncommon. Despite its long natural history, death from prostate cancer was the most common cause of mortality in this population with locally advanced tumors, reflecting the need for more effective therapy.

Validation of the soft tissue restraints in a force-controlled knee simulator

In vitro testing of total knee replacements (TKRs) is important both at the design stage and after the production of the final components. It can predict long-term in vivo wear of TKRs. The two philosophies for knee testing are to drive the motion by displacement or to drive the motion by force. Both methods have advantages and disadvantages. For force control an accurate simulation of soft tissue restraints is required. This study was devised to assess the accuracy of the soft tissue restraints of the force-controlled Stanmore knee simulator in simulating the restraining forces of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). In order to do this, human cadaver knee joints were subjected to the ISO Standard Walking Cycle. The resulting kinematics were monitored when the soft tissue structures were intact, when the ACL and PCL were resected, and when they were simulated by springs positioned anteriorly and posteriorly. The stiffness of the springs was determined from the literature. Two different stiffnesses of springs were used which were 7.24 N/mm (designated as soft springs) and 33.8 N/mm (designated as hard springs). All the intact knees showed displacements that were within the range of the machine. Cutting the ACL and PCL resulted in anterior and posterior motion and internal external rotation that were significantly greater than the intact knee. Results showed that when the ACL and PCL were cut hard springs positioned anterior and posterior to the knee returned the knee to near normal anterior-posterior (AP) motion. Using hard springs in the posterior position in any condition reduced rotational displacements. Therefore using springs in a force-controlled simulator is a compromise. More accuracy may be obtained using springs that are of intermediate stiffness.

Loss of heterozygosity of M6P/IGF2R gene is an early event in the development of prostate cancer

BACKGROUND

The genetic events leading to initiation and/or progression of prostate cancer are not well characterized. The gene coding for the mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R) has recently been identified as a tumor suppressor in several types of cancer. The purpose of the present study is to determine whether the M6P/IGF2R gene is inactivated in human prostate cancer, and if so, whether this is an early or late transformational event.

METHODS

In total, 43 patients with prostate cancer treated by radical prostatectomy, with archival material available for analysis, were assessed for loss of heterozygosity (LOH) in the M6P/IGF2R gene using six different gene-specific nucleotide polymorphisms. Regions of tumor, normal prostate and premalignant high-grade prostate intraepithelial neoplasia (PIN) were identified and cells were excised by laser capture microdissection (LCM). DNA segments were amplified using polymerase chain reaction (PCR).

RESULTS

The M6P/IGF2R gene was polymorphic in 83.7% (36/43) of patients, and 41.7% (15/36) of these informative patients had LOH in the tumor tissue. In 11/15 patients with LOH in malignant tissue, high-grade PIN could be identified, and 63.6% (7/11) also had LOH in this premalignant tissue.

CONCLUSIONS

This study is the first to find that the M6P/IGF2R gene is inactivated in prostate cancer. LOH in premalignant tissue as well suggests that mutation in the M6P/IGF2R gene is an early event in the development of prostate cancer, supporting the conclusion that it functions as a tumor suppressor gene in this disease.

Using plasma transforming growth factor beta-1 during radiotherapy to select patients for dose escalation

PURPOSE

The ability to prescribe treatment based on relative risks for normal tissue injury has important implications for oncologists. In non-small-cell lung cancer, increasing the dose of radiation may improve local control and survival. Changes in plasma transforming growth factor beta (TGFbeta) levels during radiotherapy (RT) may identify patients at low risk for complications in whom higher doses of radiation could be safely delivered.

PATIENT AND METHODS

Patients with locally advanced or medically inoperable non-small-cell lung cancer received three-dimensional conformal RT to the primary tumor and radiographically involved nodes to a dose of 73.6 Gy (1.6 Gy twice daily). If the plasma TGFbeta level was normal after 73.6 Gy, additional twice daily RT was delivered to successively higher total doses. The maximum-tolerated dose was defined as the highest radiation dose at which < or = one grade 4 (life-threatening) late toxicity and < or = two grade 3 to 4 (severe life-threatening) late toxicities occurred.

RESULTS

Thirty-eight patients were enrolled. Median follow-up was 16 months. Twenty-four patients were not eligible for radiation dose escalation beyond 73.6 Gy because of persistently abnormal TGFbeta levels. Fourteen patients whose TGFbeta levels were normal after 73.6 Gy were escalated to 80 Gy (n = 8) and 86.4 Gy (n = 6). In the 86.4-Gy group, dose-limiting toxicity was reached because there were two (33%) grade 3 late toxicities.

CONCLUSION

It is feasible to use plasma TGFbeta levels to select patients for RT dose escalation for non-small-cell lung cancer. The maximum-tolerated dose using this approach is 86.4 Gy.

Predicting the risk of symptomatic radiation-induced lung injury using both the physical and biologic parameters V(30) and transforming growth factor beta

PURPOSE

To correlate the volume of lung irradiated with changes in plasma levels of the fibrogenic cytokine transforming growth factor beta (TGFbeta) during radiotherapy (RT), such that this information might be used to predict the development of symptomatic radiation-induced lung injury (SRILI).

METHODS AND MATERIALS

The records of all patients with lung cancer treated with RT with curative intent from 1991 to 1997 on a series of prospective normal tissue injury studies were reviewed. A total of 103 patients were identified who met the following inclusion criteria: (1) newly diagnosed lung cancer of any histology treated with RT +/- chemotherapy with curative intent; (2) no evidence of distant metastases or malignant pleural effusion; (3) no thoracic surgery after lung RT; (4) no endobronchial brachytherapy; (5) follow-up time more than 6 months; (6) plasma TGFbeta1 measurements obtained before and at the end of RT. The concentration of plasma TGFbeta1 was measured by an enzyme-linked immunosorbent assay. Seventy-eight of the 103 patients were treated with computed tomography based 3-dimensional planning and had dose-volume histogram data available. The endpoint of the study was the development of SRILI (modified NCI [National Cancer Institute] common toxicity criteria).

RESULTS

The 1-year and 2-year actuarial incidence of SRILI for all 103 patients was 17% and 21%, respectively. In those patients whose TGFbeta level at the end of RT was higher than the pre-RT baseline, SRILI occurred more frequently (2-year incidence = 39%) than in patients whose TGFbeta1 level at the end of RT was less than the baseline value (2-year incidence = 11%, p = 0.007). On multivariate analysis, a persistent elevation of plasma TGFbeta1 above the baseline concentration at the end of RT was an independent risk factor for the occurrence of SRILI (p = 0.004). The subgroup of 78 patients treated with 3-dimensional conformal radiotherapy, who consequently had dose-volume histogram data, were divided into groups according to their TGFbeta1 kinetics and whether their V(30) level was above or below the median of 30%. Group I (n = 29), with both a TGFbeta1 level at the end of RT that was below the pre-RT baseline and V(30) < 30%; Group II (n = 35), with a TGFbeta1 level at the end of irradiation that was below the baseline but a V(30) > or = 30% or with a TGFbeta1 level at the end of RT that was above the pre-RT baseline but V(30) < 30%; Group III (n = 14), with both a TGFbeta1 level at the end of RT that was above the baseline and V(30) > or = 30%. A significant difference was found in the incidence of SRILI among these three groups (6.9%, 22.8%, 42.9%, respectively, p = 0.02).

CONCLUSIONS

(1) An elevated plasma TGFbeta1 level at the end of RT is an independent risk factor for SRILI; (2) The combination of plasma TGFbeta1 level and V(30) appears to facilitate stratification of patients into low, intermediate, and high risk groups. Thus, combining both physical and biologic risk factors may allow for better identification of patients at risk for the development of symptomatic radiation-induced lung injury.

Survival of patients with diabetes and multivessel coronary artery disease after surgical or percutaneous coronary revascularization: results of a large regional prospective study. Northern New England Cardiovascular Disease Study Group

OBJECTIVES

We sought to assess survival among patients with diabetes and multivessel coronary artery disease (MVD) after percutaneous coronary intervention (PCI) and after coronary artery bypass grafting surgery (CABG).

BACKGROUND

The Bypass Angioplasty Revascularization Investigation (BARI) demonstrated that diabetics with MVD survive longer after initial CABG than after initial PCI. Other randomized trials or observational databases have not conclusively reproduced this result.

METHODS

A large, regional database was linked to the National Death Index to assess five-year mortality. Of 7,159 consecutive patients with diabetes who underwent coronary revascularization in northern New England during 1992 to 1996, 2,766 (38.6%) were similar to those randomized in the BARI trial. Percutaneous coronary intervention was the initial revascularization strategy in 736 patients and CABG in 2,030. Cox proportional hazards regression was used to calculate risk-adjusted hazard ratios (HR) and 95% confidence intervals (CI 95%).

RESULTS

Patients who underwent PCI were younger, had higher ejection fractions and less extensive coronary disease. After adjusting for differences in baseline clinical characteristics, patients with diabetes treated with PCI had significantly greater mortality relative to those undergoing CABG (HR = 1.49; CI 95%: 1.02 to 2.17; p = 0.037). Mortality risk tended to increase more among 1,251 patients with 3VD (HR = 2.02; CI 95%: 1.04 to 3.91; p = 0.038) than among 1,515 patients with 2VD (HR = 1.33; CI 95%: 0.84 to 2.1; p = 0.21).

CONCLUSIONS

In this analysis of a large regional contemporary database of patients with diabetes selected to be similar to those enrolled in the BARI trial, five-year mortality was significantly increased after initial PCI. This supports the BARI conclusion on initial revascularization of patients with diabetes and MVD.

Loss of heterozygosity at the mannose 6-phosphate insulin-like growth factor 2 receptor (M6P/IGF2R) locus predisposes patients to radiation-induced lung injury

PURPOSE

To investigate the relationship between loss of heterozygosity (LOH) at the mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R) gene locus and the development of radiation-induced lung injury.

MATERIAL AND METHODS

Thirty-five lung cancer patients with both stored plasma for Transforming Growth Factor beta1 (TGFbeta1) analysis and sufficient quantities of archival pathology tissue to screen for LOH were studied. All patients had been treated with thoracic radiotherapy for their malignancy and had radiographically detectable tumor present before beginning radiotherapy. Tumor and normal cells were microdissected from archival lung cancer pathology specimens. Two polymorphisms in the 3' untranslated region of the M6P/IGF2R were used to screen for LOH. Plasma TGFbeta1 levels were measured using acid-ethanol extraction and an ELISA. TGFbeta1 and M6P/IGF2R protein expression was estimated by immunofluorescence and immunohistochemical staining. Symptomatic radiation pneumonitis was scored according to National Cancer Institute Common Toxicity Criteria without knowledge of the results of TGFbeta or LOH analyses.

RESULTS

Of the 35 patients, 10 were homozygous for this polymorphism (noninformative) and were excluded. Of the 25 informative patients, 13 had LOH. Twelve of 13 patients with LOH had increased pretreatment plasma TGFbeta1 levels, vs. 3/12 patients without LOH (p < 0.01). A decrease or loss of M6P/IGF2R protein in the malignant cell accompanied by increased latent TGFbeta1 protein in extracellular matrix and tumor stroma was found in tumors with LOH, suggesting that this mutation resulted in loss of function of the receptor. Seven of 13 (54%) LOH patients developed symptomatic radiation-induced lung injury vs. 1/12 (8%) of patients without LOH (p = 0.05).

CONCLUSION

Loss of the M6P/IGF2R gene strongly correlates with the development of radiation pneumonitis after thoracic radiotherapy (RT). Furthermore, patients with LOH (in the setting of measurable tumor) are much more likely to have elevated plasma TGFbeta, suggesting an inability to normally process this cytokine. Thus, loss of the M6P/IGF2R gene may predispose patients to the development of radiation-induced lung injury.

Risks of morbidity and mortality in dialysis patients undergoing coronary artery bypass surgery. Northern New England Cardiovascular Disease Study Group

BACKGROUND

Although dialysis patients are undergoing CABG with increasing frequency, large studies specifically comparing patient characteristics and procedure-related risks in this population have not been performed.

METHODS AND RESULTS

We conducted a regional prospective cohort study of 15,500 consecutive patients undergoing CABG in northern New England from 1992 to 1997. We used multiple logistic regression analysis to examine associations between preoperative dialysis-dependent renal failure and postoperative events and to adjust for potentially confounding variables. The 279 dialysis-dependent renal failure patients (1.8%) were 4.4 times more likely to experience in-hospital mortality than were other CABG patients (12.2% versus 3.0%, respectively; P:<0.001). Dialysis-dependent renal failure patients were older and had more comorbidities and more severe cardiac disease than did other CABG patients. After adjusting for these factors in multivariate analysis, however, dialysis-dependent renal failure patients remained 3.1 times more likely to die after CABG (adjusted odds ratio [OR] 3.1, 95% CI 2.1 to 4.7; P:<0.001). Dialysis-dependent renal failure patients compared with other CABG patients also had a substantially increased risk of postoperative mediastinitis (3.6% versus 1.2%, respectively; adjusted OR 2.4, 95% CI 1.2 to 4.7; P:=0.011) and postoperative stroke (4.3% versus 1.7%, respectively; adjusted OR 2. 1, 95% CI 1.1 to 3.9; P:=0.016), even after controlling for potentially confounding variables. Risks of reexploration for bleeding were similar for patients with and without dialysis-dependent renal failure.

CONCLUSIONS

Preoperative dialysis-dependent renal failure is a strong independent risk factor for in-hospital mortality and mediastinitis after CABG.

Radiotherapy for a rising prostate-specific antigen after radical prostatectomy: the first 10 years

PURPOSE

To determine the results of radiotherapy (RT) to the prostate bed for a presumed local recurrence heralded by a rising prostate-specific antigen (PSA) after radical prostatectomy (RP) for adenocarcinoma of the prostate.

METHODS AND MATERIALS

From 1987 to 1997, 89 patients were treated by the senior author (M.S.A.) with RT to the prostate bed for a rising PSA after RP. No patients had clinical or radiographic evidence of local or distant disease. The RT technique was usually a 4-field box with fields shaped to protect normal tissues. Of the 89 patients, 36 (40%) were treated using three-dimensional conformal RT (3DRT) using beam's eye view technique; the remaining 53 patients (60%) were irradiated using a standard two-dimensional approach. The median dose was 66 Gy. Patients were followed at 3- to 6-month intervals after completing RT with a history, physical examination, and PSA. Late normal tissue toxicity was scored using Radiation Therapy Oncology Group (RTOG) criteria. An undetectable PSA was required to be considered free of prostate cancer (NED).

RESULTS

Eighty-seven percent of patients had pathologic stage III/IV disease. Three patients had lymph node involvement. The median PSA prior to RT was 1.4 ng/mL. The median Gleason score was 7. Of the 89 patients, 64 (72%) became NED. Of these 64 patients, 47 (73%) remain NED at last follow-up (median follow-up = 48 months). The estimated 4-year disease-free survival (DFS) for all patients is 50%. The DFS at 4 years was 61% for the 3DRT patients vs. 41% for those treated without 3DRT (p = 0.006). Late complications (Grade 1/2 only), however, were significantly more common in the 3DRT group. On multivariate analysis, only dose > 65 Gy predicted for better DFS.

CONCLUSIONS

Pelvic RT may achieve sustained remission of prostate cancer for about half of patients with a rising PSA after RP, at least in the intermediate term. Doses > 65 Gy are recommended. 3DRT may offer improved disease-free survival over non-3D approaches, however, this issue requires further study.

The role of lung perfusion imaging in predicting the direction of radiation-induced changes in pulmonary function tests

BACKGROUND

The aim of this study was to determine whether preradiation (pre-RT) single photon emission computed tomography (SPECT) lung perfusion scans can be used to predict RT-induced changes in pulmonary function tests (PFTs).

METHODS

Ninety-four patients irradiated for thoracic tumors had pre-RT SPECT lung perfusion scans. The presence of SPECT hypoperfusion distal to a central mediastinal tumor was qualitatively assessed visually without knowledge of PFT changes. Patients were grouped based on whether the diffusion capacity (DLCO) ever increased post-RT. Comparisons of patient groups were performed using 1-tailed Fisher exact tests. Patient follow-up was 6-56 months (mean, 30 months). To assess SPECT hypoperfusion objectively, the average dose to the computed tomography (CT)-defined lung was compared with the weighted-average dose (based on relative perfusion) to the SPECT-defined lung. The ratio between the CT- and SPECT-defined mean lung dose provided a quantitative assessment of hypoperfusion. The mean ratio for patients with central tumor and adjacent hypoperfusion was compared with that of the others (Wilcoxon rank-sum one-sided test).

RESULTS

In patients with central tumors, 41% (9 of 22) with adjacent hypoperfusion had improvements in DLCO following radiation, versus 18% (3 of 17) of those without hypoperfusion (P = 0.11). In patients with lung carcinoma, the corresponding ratios were 40% (8 of 20) and 10% (1 of 10), respectively (P = 0.10). The mean ratio of CT dose to SPECT dose was 1.35 for patients with central tumors and adjacent hypoperfusion versus 1.16 for others (P = 0.017).

CONCLUSIONS

The presence of SPECT hypoperfusion adjacent to a central mediastinal mass may identify patients likely to have improved PFTs following RT. Thus, SPECT imaging may be useful in models for predicting radiation-induced changes in PFTs.