Acute Segmental Testicular Infarction at Contrast-Enhanced Ultrasound: Early Features and Changes During Follow-Up

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1 Genitourinary Imaging Original Research Bertolotto et al. Ultrasound of Testicular Infarction Genitourinary Imaging Original Research Michele Bertolotto 1 Lorenzo E. Derchi 2 Paul S. Sidhu 3 Giovanni Serafini 4 Massimo Valentino 5 Nicolas Grenier 6 Maria. Cova 1 Bertolotto M, Derchi LE, Sidhu PS, et al. Keywords: acute scrotal pain, contrast-enhanced ultrasound, infarction, testis DOI: /JR Received pril 17, 2010; accepted after revision September 19, Department of Radiology, Ospedale di Cattinara, University of Trieste, Strada di Fiume 447, 34149, Trieste, Italy. ddress correspondence to M. Bertolotto (bertolot@units.it). 2 Department of Radiology, University of Genoa, Genoa, Italy. 3 Department of Radiology, King s College Hospital, London, UK. 4 Department of Radiology, Ospedale S. Corona, Pietra Ligure, Italy. 5 Department of Emergency Radiology, Policlinico S. Orsola-Malpighi, Bologna, Italy. 6 Diagnostic and Interventional Radiology Service, Groupe Hospitalier Pellegrin, Bordeaux, France. JR 2011; 196: X/11/ merican Roentgen Ray Society cute Segmental Testicular Infarction at Contrast-Enhanced Ultrasound: Early Features and Changes During Follow-Up OBJECTIVE. The purpose of this retrospective study was to assess whether contrast-enhanced ultrasound is useful for characterization of acute segmental testicular infarction. MTERILS ND METHODS. Twenty men with acute scrotal pain and suspected segmental testicular infarction underwent contrast-enhanced ultrasound. Three patients underwent orchiectomy. For the other patients, the final diagnosis was based on the absence of tumor markers and a change in the size or shape of the tumor during follow-up. Forty-nine color Doppler ultrasound studies (16 within 24 hours of the onset of pain; 14, 2 17 days after pain onset; 19 after 1 month or more), and 38 contrast-enhanced ultrasound studies (13 within 24 hours after pain onset; nine, 2 17 days; 16 after 1 month or more) were performed. RESULTS. Fourteen of 16 lesions examined within 24 hours were oval, and two were wedge shaped. Eight lesions were isoechoic to the testis, six were hypoechoic, and two had mixed echogenicity. Twelve lesions were avascular and four were hypovascular at color Doppler examination. Contrast-enhanced ultrasound showed avascular parenchymal lobules in all cases and without perilesional rim enhancement in 12 of 13 studies. Two to 17 days after the symptoms appeared, contrast-enhanced ultrasound showed avascular lobules in all cases and perilesional rim enhancement in eight examinations. fter 1 month or more, contrastenhanced ultrasound depicted intralesional vascular spots in 12 of 14 infarcts. Perilesional enhancement was absent. CONCLUSION. Recognition of lobular morphologic characteristics and the presence of perilesional rim enhancement at contrast-enhanced ultrasound can increase confidence in the diagnosis of segmental testicular infarction compared with reliance on gray-scale and color Doppler findings. Changes in lesion features during follow-up confirm the differential diagnosis from other testicular lesions and allow conservative management. cute segmental testicular infarction is an uncommon clinical situation. The etiologic mechanism is largely considered idiopathic, but cases have been associated with hypercoagulability disorders, vasculitis, torsion, trauma, infection [1], and iatrogenic vascular injury [2 4]. Segmental testicular infarction usually presents with acute scrotal pain and may resemble epididymoorchitis or torsion. lthough surgery once was recommended, imaging has improved and increases confidence in assessment in many cases. If a firm diagnosis of segmental testicular infarction is reached on the basis of imaging features and negative tumor marker results, follow-up is advocated [1, 5]. Orchiectomy is not performed if symptoms subside and the lesion remains stable or shrinks. The appearance of acute segmental testicular infarction at gray-scale and color Dop- pler ultrasound may be variable but often helps establish the benign nature of the lesion and guide diagnosis. ccording to Bilagi et al. [1], a typical segmental testicular infarct appears as a solitary solid wedgeshaped or round area in the testis. It is hypoechoic or has mixed echogenicity and has markedly diminished or no vascularity. Differential diagnosis from a tumor less vascularized than the surrounding testicular parenchyma can be difficult if the lesion is rounded and when vascularity is not completely absent at color Doppler examination [6, 7]. lthough the presence of pain argues against tumor, patients with testicular cancer may have acute symptoms [8]. Contrast-enhanced MRI has been considered the best imaging modality for obtaining a firm diagnosis of segmental testicular infarction [5, 9 11]. The lesion is not enhancing after 834 JR:196, pril 2011

2 Ultrasound of Testicular Infarction gadolinium administration, and an enhancing perilesional rim can be seen. MRI, however, cannot be used without the collaboration of the patient, is expensive, and is not widely available in emergency departments. Moreover, patients with pacemakers cannot undergo MRI, and patients with renal failure may be at risk of nephrogenic systemic fibrosis. The use of contrast-enhanced ultrasound is opening perspective on the evaluation of intratesticular flow [12 15]. In 2005, Cochlin [14] presented the case of a patient with segmental testicular infarction evaluated with contrast-enhanced ultrasound, suggesting that microbubble contrast agents would be useful for differentiating this lesion from a hypovascular tumor. To the best of our knowledge, however, no systematic studies have been performed on this topic. In this retrospective study, the gray-scale, color Doppler, and contrast-enhanced ultrasound features in 20 cases of acute segmental testicular infarction were reviewed. The lesions were evaluated soon after the onset of symptoms and during followup with the purpose of investigating whether microbubble contrast injection improves characterization of the lesions and prevents unnecessary orchiectomy. Materials and Methods We reviewed the gray-scale, color Doppler, and contrast-enhanced ultrasound images of 20 men (age range, years; mean, 46 ± 16 [SD] years; median, 43 years) with acute segmental testicular infarction examined from March 2004 to November ll patients presented with acute scrotal pain. The right testis was involved in four patients and the left in 16. No lesion was palpable. Testicular infarction was considered idiopathic in 12 of the 20 patients: 11 without other remarkable pathologic conditions and one who had undergone orchiopexy at an early age and had ipsilateral testicular atrophy. Two of the other eight patients had scrotal trauma; one patient had Schönlein-Henoch purpura; two patients had undergone ipsilateral inguinal hernia repair that was complicated by inguinal hematoma compressing the spermatic cord; one patient had epididymoorchitis; one patient was at high risk of thromboembolism because of chronic atrial fibrillation, valvular heart disease, and anticoagulation therapy; and one had abdominal and bilateral enlarged inguinal lymph nodes associated with a mixed germinal testicular tumor. In this last patient, contrast-enhanced ultrasound depicted both a segmental infarct and a nonpalpable tumor in the same testis (Table 1). Tumor marker results were negative in all but in the patient with an associated testicular tumor. Institutional review board approval and informed consent from each patient were obtained before contrast ultrasound examination. Reference Standard for Diagnosis In three patients (one with testicular tumor, two who preferred surgical exploration with the agreement of the referring clinician), the diagnosis was confirmed at histologic examination. Two of these patients underwent emergency surgery, and the third underwent surgery 1 week after the onset of symptoms and repeated ultrasound before the operation. For the other 17 patients the final diagnosis was based on a combination of clinical findings (regression or cessation of symptoms, no tumor marker abnormalities, no palpable testicular mass) and ultrasound evidence of improvement (size reduction or shape change from oval to wedge) during a follow-up period of at least 1 month (Table 1). Ultrasound Studies Gray-scale and color Doppler ultrasound were performed within 24 hours from the onset of symptoms for 16 of the 20 patients. Five of these patients underwent one or more follow-up investigations 2 17 days after the onset of symptoms. The patient with Schönlein-Henoch purpura underwent the first ultrasound study 2 days after the onset of scrotal pain. The other three patients underwent the first ultrasound study 5, 7, and 10 days after the onset of scrotal pain. ll 17 patients who did not undergo surgery underwent follow-up examinations 1 month 4 years after the episode of acute scrotal pain. Contrast-enhanced ultrasound was performed with a variety of equipment and contrast-specific modes after bolus injection of ml aqueous suspension of phospholipid-stabilized microbubbles filled with sulfur hexafluoride (Sono- Vue, BR1, Bracco) through a 20-gauge cannula followed by 10 ml normal saline flush. The power of the ultrasound beam was set for minimum microbubble destruction. Images and movie clips of the entire study were stored digitally. Thirteen patients underwent microbubble injection within 24 hours of the onset of symptoms. One patient underwent three contrast-enhanced ultrasound studies during follow-up 4, 9, and 16 days after the onset of symptoms. Four- TBLE 1: Characteristics of Patients With cute Segmental Testicular Infarction Patient No. ge (y) Testis History Reference Standard Length of Follow-Up (mo) 1 29 Left Idiopathic Histology 2 30 Left Trauma Follow-up Left Trauma Follow-up Left Idiopathic Follow-up Left Idiopathic Follow-up Right Idiopathic Follow-up Left Idiopathic Follow-up Left Idiopathic Follow-up Left Idiopathic a Follow-up Right Idiopathic Follow-up Left Idiopathic Follow-up Left Idiopathic Follow-up Right Metastasis b Histology Left Epididymoorchitis Histology Right Iatrogenic c Follow-up Left Schönlein-Henoch purpura Follow-up Left Idiopathic Follow-up Left Idiopathic Follow-up Left Iatrogenic c Follow-up Left Embolization d Follow-up 11 Note Dash ( ) indicates no follow-up. a Hypotrophic testis from orchidopexy at early age. b Spermatic cord compression by metastatic nodes from mixed testicular tumor. Upper pole segmental infarction and a mixed testicular tumor in the viable portion of testis were confirmed histologically. c Compression of the spermatic cord by iatrogenic hematoma after inguinal hernia repair. d Systemic embolization in a patient with atrial fibrillation, valvular heart disease, and anticoagulant therapy. JR:196, pril

3 Bertolotto et al. teen of 17 patients who did not undergo surgery underwent both color Doppler and contrast-enhanced ultrasound 1 month or more after the onset of symptoms. Eventually, 49 color Doppler ultrasound and 38 contrast-enhanced ultrasound studies performed at different times from the episode of acute scrotal pain were reviewed. Images and cine clips were evaluated retrospectively in consensus by two radiologists. For the purpose of the study, the following characteristics were considered: lesion echogenicity, shape and size at gray-scale ultrasound examination, lesion vascularity, presence or absence of increased perilesional flows at color or power Doppler examination, lesion characteristics, vascularity, and presence of perilesional rim enhancement at contrast-enhanced ultrasound. In patients with isoechoic lesions, shape and size were determined by measuring the hypovascular area at color Doppler examination. Because the shape of some lesions changed and became elongated over time, average diameter was used to estimate size. Lesion size within 24 hours from the onset of symptoms and that after 1 month or more were compared by Wilcoxon signed rank test. The significance of lesion distribution to the left and right testes and to the upper pole, midportion, and lower pole of the testis was evaluated by chi-square test (GraphPad Prism version 4.03, GraphPad Software). value of p < 0.05 was considered to indicate a statistically significant difference. Vascularity of the lesion and of the adjacent parenchyma was assessed by a subjective comparison with both the vascularity of the unaffected portions of the parenchyma in the diseased testis and the parenchyma of the contralateral testis. Results The features of acute segmental testicular infarction at gray-scale, color Doppler, and contrast-enhanced ultrasound are summarized in Tables 2 and 3. The lesion was located in the upper pole of the testis in 13 patients, in the lower pole in two patients, and in the middle portion in three patients. In one patient the infarction involved the middle and upper portions, and in another patient it affected the middle and lower portions. Infarction was significantly more frequent on the left side and in the upper pole of the testis (chi-square test, p < 0.01). The lesion characteristics differed over time, depending on whether the ultrasound examination was performed soon after the onset of symptoms or during short- or long-term follow-up. Early Findings Within 24 hours after the onset of symptoms, eight of 16 lesions were nearly isoechoic to the testis, barely visible at gray-scale ultrasound owing to slightly inhomogeneous echotexture (Figs. 1 and 2). Six lesions were hypoechoic to testis, and two had mixed echogenicity with hypoechoic and hyperechoic portions. Fourteen lesions were oval, and two were wedge shaped. ll but two lesions had ill-defined borders. The average lesion size ranged from 1.1 to 3 cm (mean, 2.0 ± 0.6 [SD] cm). t color Doppler examination, 12 of 16 lesions evaluated within 24 hours after the onset of symptoms were avascular (Figs. 1 and 2). The other four lesions were hypovascular compared with adjacent parenchyma. Increased perilesional flow was appreciated in eight of 16 patients. Thirteen patients underwent contrast-enhanced ultrasound within 24 hours after the TBLE 2: Findings at Gray-Scale and Color Doppler Ultrasound Evaluation of Segmental Testicular Infarction Characteristic Time From Onset of Testicular Pain < 24 h 2 17 d 1 mo No. of patients 16 (16) 9 (14) 17 (19) Shape Oval 14 7 (10) 8 (10) Wedge 2 2 (4) 9 (9) Echogenicity Isoechoic 8 2 (3) 0 Hypoechoic 6 2 (5) 17 (19) Hyperechoic 0 1 (1) 0 Mixed 2 4 (5) 0 Size (cm) a 2.0 ± ± 0.6 (1.7 ± 0.5) 1.1 ± 0.4 (1.1 ± 0.4) Vascularity vascular 12 6 (8) 10 (12) Hypovascular 4 3 (6) 7 (7) Perilesional hypervascularity Present 8 6 (10) 0 bsent 8 3 (4) 17 (19) Note Except for size, values are number of patients with number of examinations in parentheses. For size, values in parentheses are mean ± SD among examinations. a Statistically significant reduction in lesion size from < 24 hours to 1 month after pain onset (Wilcoxon signed rank test, p < 0.002). TBLE 3: Findings at Contrast-Enhanced Ultrasound Evaluation of Segmental Testicular Infarction at Different Times From Onset of Testicular Pain Characteristic Time From Onset of Testicular Pain < 24 h 2 17 d 1 mo No. of patients 13 (13) 7 (9) 14 (16) Vascularity 1 avascular lobule 6 3 (3) 2 (2) > 1 avascular lobule a 7 4 (6) 0 (0) Hypovascular b (14) Perilesional rim of enhancement Present 1 6 (8) 0 bsent 12 1 (1) 14 (16) Note Values are number of patients with number of examinations in parentheses. a Normal testicular vessels or areas of viable parenchyma separate two or more ischemic parenchymal lobules that appear avascular at contrast-enhanced ultrasound. b Intralesional vascular spots within lesion hypovascular compared with adjacent parenchyma. 836 JR:196, pril 2011

4 Ultrasound of Testicular Infarction onset of scrotal pain. single avascular portion of parenchyma was identified in six of the 13 patients (Fig. 1). Seven lesions were formed by adjacent avascular parenchymal regions separated by patent centripetal arteries, consistent with ischemic lobules with intervening parenchymal vessels (Fig. 2). Contrast-enhanced ultrasound showed that all four hypovascular lesions and three avascular lesions found with color Doppler ultrasound consisted of more than one lobule. Perilesional rim enhancement was identified at contrast-enhanced ultrasound in one of 13 patients (8%). C Short-Term Follow-Up Nine patients underwent gray-scale and color Doppler examinations 2 17 days from the onset of acute scrotal pain. Seven of these patients also underwent contrast-enhanced ultrasound. The lesions had variable echogenicity; six were avascular and three hypovascular at color Doppler ultrasound; and perilesional increased vascularity was found in six of nine patients. Contrast-enhanced ultrasound showed one (Fig. 3) or more (Figs. 2C, 2D, and 4) adjacent parenchymal areas consistent with ischemic lobules. Perilesional rim enhancement was appreciable in six of seven patients (86%). Long-Term Follow-Up The 17 patients who did not undergo surgery underwent follow-up gray-scale and color Doppler ultrasound 1 month 4 years after the episode of acute scrotal pain. During the follow-up study, 14 of these patients also underwent contrast-enhanced ultrasound. ll lesions were hypoechoic; nine of 17 were wedge shaped, and eight were oval. The size range was cm (average, 1.1 ± 0.4 cm). ll but four lesions had ill-defined borders. There was a statistically significant reduction in lesion size compared with earlier examinations (Wilcoxon signed rank test, p < 0.001). Ten of 17 lesions were avascular at color Doppler examination, and seven were hypovascular. t contrast-enhanced ultrasound, 12 of 14 lesions had intralesional vascular spots (Fig. 3), Fig year-old man with right acute testicular pain for less than 24 hours., Gray-scale ultrasound image shows inhomogeneous area (arrowheads) in upper pole of testis. B, Power Doppler ultrasound image shows avascular area (asterisk) surrounded by parenchyma with subjectively increased vascularization. C, Contrast-enhanced ultrasound image shows ischemic lobule (asterisk) without perilesional enhancement consistent with acute segmental infarction. and two were avascular. No lesion had a perilesional enhancing rim. Discussion The key factor that allows differential diagnosis between segmental testicular infarction and tumor is recognition that the lesion is formed by one or more ischemic testicular lobules. Identification of the lobular morphologic features and the ischemic nature is straightforward in cases of wedge-shaped hypoechoic lesions that are avascular at color Doppler examination. Segmental testicular infarction, however, can be round and appear not completely avascular at color Doppler examination [1, 6]. When intralesional color spots are present, infarction cannot be safely differentiated from a hypovascular tumor. Moreover, increased perilesional parenchymal flow signal may be present in segmental infarction that is difficult to differentiate from peripheral vascularization, especially in small lesions [14], or from the hypervascular rim often visible in testicular abscess- B JR:196, pril

5 Bertolotto et al. Fig year-old man with left acute testicular pain for 24 hours., Gray-scale ultrasound image shows inhomogeneous area (arrowheads) in lower pole of testis. B, Color Doppler ultrasound image shows avascular area (asterisk) surrounded by parenchyma with subjectively increased vascularization. C, Contrast-enhanced ultrasound image shows multiple ischemic lobules without perilesional enhancement separated by normal centripetal vessels (arrowheads) arising from capsular vessels (arrows). D, Color Doppler ultrasound image obtained 9 days after C shows hypoechoic wedge-shaped hypovascular lesion (asterisk). Vascularization of surrounding parenchyma is subjectively increased. E, Contrast-enhanced ultrasound image obtained 9 days after C shows ischemic lobules with intervening areas of viable parenchyma (arrows). Perilesional rim (arrowheads) of enhancement is evident. C es. In addition, small testicular tumors may appear avascular at color Doppler examination [7]. In these situations, differentiation of infarction from hypovascular tumor can be difficult or even impossible [1, 9]. Results during careful color Doppler investigation may suggest the correct diagnosis of segmental testicular infarction in many cases, but in clinical practice, diagnosis is often made after orchiectomy for a suspected tumor. In our series contrast-enhanced ultrasound improved characterization of acute testicular segmental infarction, showing the morphologic features of this lesion, which are different from those of hypovascular tumors. Infarction presents as one or more avascular areas separated by normal vessels, consistent with ischemic testicular lobules. Unlike color Doppler ultrasound, contrast-enhanced ultrasound shows vessels for a long time after injection of microbubbles, and differentiation B D E 838 JR:196, pril 2011

6 Ultrasound of Testicular Infarction between normal centripetal testicular arteries originating from the capsular arteries and tumor neovascularization is straightforward. We found gray-scale and color Doppler features of segmental testicular infarction similar to those described in other studies [1, 5, 9, 11, 14 17]. The spectrum of findings differed depending on the time between the onset of testicular pain and the ultrasound examination. Lesions identified earlier were more often rounded and nearly isoechoic to testis and had ill-defined margins. They became more conspicuous and smaller over time and hypoechoic to testis and often were wedge shaped. s it was in the study by Bilagi et al. [1], in our series segmental infarction was more frequent in the upper pole of the testis (chisquare test, p < 0.01). Predisposition to partial infarction in the upper hemisphere of the testis can result from impairment of arterial flow due to vascular abnormalities [9]. Unlike other authors [1, 5, 9], we found segmental infarction had a statistically significant predilection for the left testis (chisquare test, p < 0.01). The explanation for this difference is not clear; it may be related to differences in patient populations. natomic factors also may explain our finding. The left-sided prevalence of varicocele is well known owing to differences in testicular venous drainage on the two sides. This condition may be associated with decreased testicular blood flow [18]. Slightly compromised left venous drainage associated with reduction in arterial flow may also be present in patients without varicocele, increasing the likelihood of finding infarcts in our series. C In eight of 16 patients in our series, slightly increased perilesional parenchymal flow was appreciable at color Doppler examination within 24 hours after the onset of pain; in 10 of 14 patients, this finding was made at examinations performed 2 17 days after pain onset. Perilesional hyperemia faded in chronic segmental infarction. This feature was described by Gianfrilli et al. [17] and may be due to perilesional inflammatory changes around the infarcted areas. ccording to Bilagi et al. [1], this finding can be interpreted as a mass effect due to intralesional edema in the infarcted area that displaces the surrounding testicular tissue and causes bundling of the perilesional parenchymal vessels. cute testicular segmental infarction presenting as a round lesion with perilesional hyperemia must be differentiated from testicular Fig year-old man examined 3 days ( and B) and 1 year (C and D) after onset of left acute testicular pain., Color Doppler ultrasound image shows avascular oval hypoechoic lesion (asterisk). Vascularization of surrounding parenchyma is subjectively increased. B, Contrast-enhanced ultrasound image shows oval avascular lesion (asterisk) with perilesional enhancing rim (arrowheads). C, Follow-up color Doppler ultrasound image shows hypoechoic avascular oval area (asterisk) in upper pole of testis markedly reduced in size compared with size in. D, Follow-up contrast-enhanced ultrasound image shows hypovascular lesion (asterisk) with no perilesional rim of enhancement and few intralesional vascular spots. B D JR:196, pril

7 Bertolotto et al. abscess [19, 20], which is usually anechoic or markedly hypoechoic and has irregular wall and low-level internal echoes and increased through transmission. Moreover, an abscess does not conform to lobular distribution [16]. We have found that the perilesional hyperemia observed in segmental testicular infarction usually is more pronounced than the hypervascular rim of an abscess. s in gray-scale and color Doppler ultrasound, after microbubble injection we found the spectrum of findings depended on the time between the onset of testicular pain and the contrast-enhanced ultrasound examination. Unlike perilesional hyperemia at color Doppler examination, which is identified within 24 hours from the onset of pain in 50% of patients, perilesional rim enhancement was observed early at contrast-enhanced ultrasound in only one of 13 (8%) patients. It was prevalent (6/7, 86%), however, in examinations performed 2 17 days after the onset of pain. No patient examined longer from the episode of acute scrotal pain presented with perilesional rim enhancement. This temporal evolution suggests a different pathologic basis. Because radiologic-pathologic correlation was not performed in our series, we can only speculate on the anatomic basis of perilesional rim enhancement. Histologic studies of the heart have shown that vessels bordering an infarcted area actively proliferate to form new channels under the influence of several hypoxia-inducible peptides, such as vascular endothelial growth factor [21]. Other experimental studies have shown that vascular endothelial growth factor also mediates angiogenesis in ischemic testis [22]. It is conceivable that the perilesional rim enhancement observed at contrast-enhanced ultrasound represents histologic evidence of granulation tissue, including inflammatory cells, fibroblasts, and neovasculature, in response to ischemia, which is not present either during the early phase or in old infarcts [23, 24]. If this interpretation is correct, perilesional rim enhancement at contrast-enhanced ultrasound may be a sign of subacute segmental testicular infarction. Intralesional vascular spots were identified at contrast-enhanced ultrasound in 12 of 14 patients with segmental testicular infarction examined 1 month or more after the onset of symptoms. Differential diagnosis between chronic segmental infarction and hypovascular testicular tumor based on imaging findings alone can be difficult in the care of these patients, especially if the lesion is rounded [7]. The diagnosis of chronic segmental infarction, however, is possible on the basis of the combination of a history of testicular pain, imaging features, and changes in shape, size, and characteristics from previous ultrasound examinations. possible explanation for the presence of intralesional vessels in chronic segmental infarction is found in heart studies showing that scar is living, dynamic tissue with a neovasculature [25]. This study had several limitations. First, the number of patients with segmental testicular infarction evaluated was relatively low, reflecting the rarity of this pathologic condition. Second, in our series, segmental testicular infarction was first suspected at conventional sonography and then studied with contrast-enhanced ultrasound, limiting falsepositive and false-negative results. Moreover, no other pathologic conditions that present with similar findings, hypovascular and infarcted tumors in particular, were considered. Therefore, our data cannot be used to extrapolate into clinical practice the importance of contrast-enhanced ultrasound in the characterization of testicular lesions in the general population of patients. Third, histologic correlation was not obtained in most of the cases. Orchiectomy, however, is not currently indicated in the management of segmental testicular infarction if a firm diagnosis is reached with clinical and imaging findings [1, 5]. Fourth, color Doppler and contrast-enhanced ultrasound were the only imaging modalities available in this series because MRI was not performed. lthough according to Bilagi et al. [1], MRI is not needed to characterize segmental testicular infarction [1], other authors [5, 9 11, 26] suggest that this technique is excellent for establishing the diagnosis in equivocal cases. We conclude that acute segmental testicular infarction often presents with typical features at ultrasound, but differentiation from tumors can be difficult. Moreover, approximately one half of infarcts are nearly isoechoic to testis within 24 hours after the onset of pain and are identified mainly as a hypovascular region at color Doppler examination. In our series, contrast-enhanced ultrasound improved lesion conspicuity and depicted the anatomic characteristics. s in gray-scale and color Doppler examinations, Fig year-old man with 2-day history of left acute testicular pain., Color Doppler ultrasound image shows avascular inhomogeneously hypoechoic lesion (asterisk). Vascularization of surrounding parenchyma is subjectively increased. B, Contrast-enhanced ultrasound image shows ischemic lobules with intervening viable parenchyma (arrow). Perilesional rim of enhancement is present. B 840 JR:196, pril 2011

8 Ultrasound of Testicular Infarction lesion changes over time are important for confirming a diagnosis with contrast-enhanced ultrasound. In particular, perilesional rim enhancement is evident within 2 17 days after the onset of symptoms. Later in followup, the appearance of the lesion is not characteristic because the perilesional enhancing rim disappears, and intralesional vascular signal often is identified. Comparison with results of previous examinations, however, shows a reduction in lesion size and changes in vascular features that lead to a firm diagnosis of segmental testicular infarction that prevents unnecessary orchiectomy. References 1. Bilagi P, Sriprasad S, Clarke JL, Sellars ME, Muir GH, Sidhu PS. Clinical and ultrasound features of segmental testicular infarction: six-year experience from a single centre. Eur Radiol 2007; 17: Magill P, Jacob T, Lennon GM. rare case of segmental testicular infarction. Urology 2007; 69:983e7 983e8 3. Mincheff T, Bannister B, Zubel P. Focal testicular infarction from laparoscopic inguinal hernia repair. JSLS 2002; 6: Secil M, Kocyigit, slan G, et al. Segmental testicular infarction as a complication of varicocelectomy: sonographic findings. J Clin Ultrasound 2006; 34: Madaan S, Joniau S, Klockaerts K, et al. Segmental testicular infarction: conservative management is feasible and safe. Eur Urol 2008; 53: Chin SC, Wu CJ, Chen, Hsiao HS. Segmental hemorrhagic infarction of testis associated with epididymitis. J Clin Ultrasound 1998; 26: Horstman WG, Melson GL, Middleton WD, ndriole GL. Testicular tumors: findings with color Doppler US. Radiology 1992; 185: Guthrie J, Fowler RC. Ultrasound diagnosis of testicular tumours presenting as epididymal disease. Clin Radiol 1992; 46: Fernandez-Perez GC, Tardaguila FM, Velasco M, et al. Radiologic findings of segmental testicular infarction. JR 2005; 184: Kodama K, Yotsuyanagi S, Fuse H, Hirano S, Kitagawa K, Masuda S. Magnetic resonance imaging to diagnose segmental testicular infarction. J Urol 2000; 163: Ruibal M, Quintana JL, Fernandez G, Zungri E. Segmental testicular infarction. J Urol 2003; 170: Paltiel HJ, Kalish L, Susaeta R, Frauscher F, O Kane PL, Freitas-Filho LG. Pulse-inversion US imaging of testicular ischemia: quantitative and qualitative analyses in a rabbit model. Radiology 2006; 239: Thierman JS, Clement GT, Kalish L, O Kane PL, Frauscher F, Paltiel HJ. utomated sonographic evaluation of testicular perfusion. Phys Med Biol 2006; 51: Cochlin D. cute testicular pain. Imaging 2005; 17: Stewart VR, Sidhu PS. The testis: the unusual, the rare and the bizarre. Clin Radiol 2007; 62: Ledwidge ME, Lee DK, Winter TC 3rd, Uehling DT, Mitchell CC, Lee FT Jr. Sonographic diagnosis of superior hemispheric testicular infarction. JR 2002; 179: Gianfrilli D, Isidori M, Lenzi. Segmental testicular ischaemia: presentation, management and follow-up. Int J ndrol 2009; 32: Tarhan S, Gumus B, Gunduz I, et al. Effect of varicocele on testicular artery blood flow in men: color Doppler investigation. Scand J Urol Nephrol 2003; 37: Bhatt S, Rubens DJ, Dogra VS. Sonography of benign intrascrotal lesions. Ultrasound Q 2006; 22: Dogra VS, Gottlieb RH, Rubens DJ, Liao L. Benign intratesticular cystic lesions: US features. RadioGraphics 2001; 21:S273 S Shinohara K, Shinohara T, Mochizuki N, et al. Expression of vascular endothelial growth factor in human myocardial infarction. Heart Vessels 1996; 11: Hashimoto H, Ishikawa T, Yamaguchi K, Shiotani M, Fujisawa M. Experimental ischaemia-reperfusion injury induces vascular endothelial growth factor expression in the rat testis. ndrologia 2009; 41: Jordan GH. Segmental hemorrhagic infarct of testicle. Urology 1987; 29: Li M, Fogarty J, Whitney KD, Stone P. Repeated testicular infarction in a patient with sickle cell disease: a possible mechanism for testicular failure. Urology 2003; 62: Wang B, nsari R, Sun Y, Postlethwaite E, Weber KT, Kiani MF. The scar neovasculature after myocardial infarction in rats. m J Physiol Heart Circ Physiol 2005; 289:H108 H Parenti GC, Feletti F, Brandini F, et al. Imaging of the scrotum: role of MRI. Radiol Med 2009; 114: JR:196, pril