Subramanyam Padma, Sundaram P Shanmuga
Department of Nuclear Medicine and PET CT, Amrita Institute of Medical Sciences, Cochin, Kerala, India.
Indian J Nucl Med. 2018 Apr-Jun;33(2):105-111. doi: 10.4103/ijnm.IJNM_149_17.
Forced expiratory volume in one second (FEV) is an independent predictor for respiratory morbidity. Reports are varied and controversial substantiating the use of either lung perfusion (Q) or ventilation (V) scintigraphy as a single stage investigation to predict postoperative (ppo) FEV in patients scheduled for lung resection surgeries. It is said that there is no additional benefit by performing both V/Q scan. As per one of the recommendations, no further respiratory function tests are required for a lobectomy if the postbronchodilator FEV is >1.5 l. We wanted to study the ppo FEV in patients with FEV of <1.5 L scheduled for lung surgeries. Being a high-risk population, we wanted to assess (a) whether the ppo changes by this combined V/Q imaging and (b) whether the incidence of respiratory complication in the postoperative setting of this subgroup is different, (c) and study the short- and long-term clinical outcome.
Fifty-two high-risk patients (with comorbidities) and borderline preoperative FEV of 1.5 L or less planned for lung resection were enroled in this prospective study. V and Q scans were performed, and tracer uptake percentage was tabulated.
Tracer uptake in each lung was quantitated. Manual method of ROI drawing is preferred in high risk patients with reduced pulmonary reserve over the automatic method. Based on uptake patterns by V/Q scans, 4 different types of patterns were tabulated. Eighty-eight percentage of centrally placed tumors showed the difference in uptake patterns. Chronic obstructive pulmonary disease patients usually showed more modest ventilatory defects (categorised as type 2 or 3). Lung tumours produce erratic uptake patterns (Type 4) which depend heavily on their location and extent. The range of FEV predicted was 0.6-1.38 L/min.
We recommend that combined imaging should be performed in patients with borderline pulmonary reserve to derive the benefit of surgery as it provides a realistic ppo FEV in patients with moderate to severely damaged lung. Centrally placed hilar or bronchial tumors (even those <2 cm in size), produce discrepancies in V/Q distribution pattern. Patient who was thought ineligible for surgery due to low baseline FEV may be actually be operable by this combined imaging if uptake pattern is better in V or Q scan with a good outcome. Accurate estimation of postop FEV in fact helps the surgical team to implement measures to prepare high risk patients to reduce postoperative complications, enable faster weaning from ventilatory support and ensure favourable prognosis.
一秒用力呼气容积（FEV）是呼吸系统发病的独立预测指标。关于将肺灌注（Q）或通气（V）闪烁扫描作为预测肺切除手术患者术后（ppo）FEV的单阶段检查方法，相关报道各异且存在争议。据说进行V/Q扫描并无额外益处。根据其中一项建议，如果支气管扩张剂后FEV＞1.5L，则肺叶切除术后无需进一步进行呼吸功能测试。我们想研究计划进行肺手术且FEV＜1.5L的患者的ppo FEV。作为高危人群，我们想评估：（a）这种联合V/Q成像后ppo的变化情况；（b）该亚组患者术后呼吸并发症的发生率是否不同；（c）并研究短期和长期临床结局。
本前瞻性研究纳入了52例有合并症且术前FEV临界值为1.5L或更低、计划进行肺切除的高危患者。进行了V和Q扫描，并将示踪剂摄取百分比制成表格。
对每个肺的示踪剂摄取进行了定量分析。对于肺储备功能降低的高危患者，手动绘制感兴趣区（ROI）的方法比自动方法更可取。根据V/Q扫描的摄取模式，列出了4种不同类型的模式。88%的中央型肿瘤显示出摄取模式的差异。慢性阻塞性肺疾病患者通常表现出更适度的通气缺陷（分类为2型或3型）。肺肿瘤产生不稳定的摄取模式（4型），这在很大程度上取决于其位置和范围。预测的FEV范围为0.6 - 1.38L/分钟。
我们建议，对于肺储备功能临界的患者应进行联合成像，以获得手术益处，因为它能为肺中度至重度受损患者提供实际的ppo FEV。中央型肺门或支气管肿瘤（即使大小＜2cm）会导致V/Q分布模式出现差异。因基线FEV低而被认为不适合手术的患者，如果V或Q扫描摄取模式良好且预后良好，通过这种联合成像实际上可能适合手术。准确估计术后FEV实际上有助于手术团队采取措施，为高危患者做好准备，以减少术后并发症，使患者更快脱离通气支持并确保良好预后。
